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Journal articles on the topic 'Pile foundations'
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1
Wang, Cheng Hua, and Jian Guo An. "A Nonlinear Numerical Analysis of Vertical Bearing Behavior of Bored Pile Foundations Including Defective Piles with Stem Shrinkage." Advanced Materials Research 374-377 (October 2011): 2071–77. http://dx.doi.org/10.4028/www.scientific.net/amr.374-377.2071.
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In order to investigate the influence of the defective piles with stem shrinkage on the working behavior of pile foundations under vertical loadings, a numerical model was set up for the analysis of pile foundations. A series of contrastive analyses were made to a group piled foundations including a pile with defect of stem shrinkage in a shallow or a deeper depth and a pile foundation with normal piles with a three dimensional nonlinear finite-infinite element method. The basic working behavior of the pile foundation with a defective pile of stem shrinkage was initially revealed by the results of the analyses; and the basic rules of the affects of pile stem shrinkage defect on the distribution of axial forces among piles and the bending moments in pile caps were obtained. The results of this research are not only helpful for the understanding and rational judgment of the working mechanism, but also of practical importance in the assessment of the bearing behavior of pile foundations including defective piles with stem shrinkage and in the structural designs of piles and pile caps.
2
Dhage, Amit, and S. S. Solanke. "Comparative Analysis of Raft, Pile & Piled Raft Foundation using Designing Software." IOP Conference Series: Earth and Environmental Science 1193, no. 1 (June 1, 2023): 012006. http://dx.doi.org/10.1088/1755-1315/1193/1/012006.
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Abstract Raft foundations are essentially a slab that extends the entire length of the building, sustaining and dispersing its mass to the earth. A pile foundation is a collection of columns that are erected or inserted into the ground to distribute weight to the subsoil underneath. A pile is a long, cylindrical construction made made of a sturdy substance such as concrete. Building loads are transferred to hard strata, rocks, or high-bearing-capacity soil using piles. Pinned raft foundations are a combination of a pile and a raft slab. They’re frequently used for large structures and when the soil is insufficient to avoid excessive settling. As a result of this, the soil is less strained. Pile foundations are necessary in areas where buildings are large and heavy, yet the soil beneath them is weak. In areas where settlement. Deep foundations with pile rafts can help move strata Adding piles to a raft increases the effective size of the foundation and can help it sustain horizontal loads. On a G+20 residential structure, the research of raft, pile, and stacked raft foundations was conducted using structural software safe 16. For a zone factor II earthquake, a building’s seismic study is completed. The pile raft foundation has less upward soil carrying load and less settling than the raft foundation, according to a study of the G+20 structure for pile, raft, and piled raft foundations.
3
Sharma, V. J., S. A. Vasanvala, and C. H. Solanki. "Behaviour of Load-Bearing Components of a Cushioned Composite Piled Raft Foundation Under Axial Loading." Slovak Journal of Civil Engineering 22, no. 4 (December 1, 2014): 25–34. http://dx.doi.org/10.2478/sjce-2014-0020.
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Abstract In the last decade piled raft foundations have been widely used around the world as intermediate foundation systems between piles and rafts to control the settlement of foundations. However, when those piles are structurally connected to rafts, relatively high axial stresses develop in relatively small numbers of piles, which are often designed to fully mobilize their geotechnical capacities. To avoid a concentration of stress at the head of piles in a traditional piled raft foundation, the raft is disconnected from the piles, and a cushion is introduced between them. Also, to tackle an unfavourable soil profile for a piled raft foundation, the conventional piled raft has been modified into a cushioned composite piled raft foundation, where piles of different materials are used. In the current study the behavior of cushioned foundation components, which transfer the load from the structure to the subsoil, are analyzed in detail, i.e., the thickness of the raft, the length of a long pile and the modulus of a flexible pile.
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Ahmed, Danish, Siti Noor Linda Bt Taib, Tahar Ayadat, and Alsidqi Hasan. "Numerical Analysis of the Carrying Capacity of a Piled Raft Foundation in Soft Clayey Soils." Civil Engineering Journal 8, no. 4 (April 1, 2022): 622–36. http://dx.doi.org/10.28991/cej-2022-08-04-01.
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Piled raft foundations are a common type of foundation for high-rise buildings. Unlike shallow foundations, deep foundations (piles) pass through weak or soft soil deposits and can reach stiff soil or bedrock to support the weight of the structure. In this paper, the performance of a medium embedment depth piled raft foundation in soft soil is presented. A numerical model was developed and a parametric study was conducted in order to simulate the case of such a foundation system and to investigate its performance in soft clay. This parametric study investigated the effect of the geometry of a piled raft foundation and the stiffness ratio between the pile material and clay on the performance of the foundation system in soft soil. Additionally, the failure mechanism of such a foundation system under load was examined. An analytical model was developed to predict the ultimate carrying capacity based on the observed failure mechanism. A semi-empirical model is proposed for determining the Improvement Factor (IF) of a given soil, pile, and geometric condition. Findings of the study indicate that the performance of piled raft foundations on soft soils is significantly affected by the piles’ spacing. As the ratio S/D increases, the ultimate carrying capacity of a piled raft foundation decreases. However, when this ratio exceeds 10 (S/D> 10), piles have little or no effect on the ultimate carrying capacity of this foundation system. A piled raft foundation system fails by bearing at the base of the piles and also by shear at the side of the pile group on hyperbolic plans. Doi: 10.28991/CEJ-2022-08-04-01 Full Text: PDF
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Negara, M. Iqbal Surya, Nasyiin Faqih, and Agus Juara. "Comparison of Structure Design Between Bored Pile Foundations and Pile Foundations (Case Study: Industrial Worker I Batang Flower House Construction Project)." Civilla : Jurnal Teknik Sipil Universitas Islam Lamongan 8, no. 1 (March 15, 2023): 59–68. http://dx.doi.org/10.30736/cvl.v8i1.1028.
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Field surveys and laboratories found dense soil layers up to a depth of 14 m, so an alternative to drilled pile or pile foundations was used. This study aims to compare the pile and drilled pile foundation plans with the same soil data, loads, and dimensions. Analysis by calculating the pile foundation plan compared to the drilled pile foundation so that the planning results are obtained, soil bearing capacity, pile group efficiency, number of piles and drilled piles, RAB (budget plan), and drilled pile plans. Compared to 50cm square piles and 40×40cm square piles, the bearing capacity of a single pile (Qult) is 44.5 tons, and the bored pile foundation is 54.72 tons. The pile resistance (f) is 38.79 tons for piles with a diameter of 40 x 40 cm and 38.79 tons for drilled piles with a diameter of 50 cm. One pile's allowable pressure-bearing capacity (Pa) is 14.48 tons, and one drilled pile is 17.48 tons. The permissible tensile strength (Pta) for one pile is 11.64 tons, and for one drilled pile is 14.46 tons. The pile foundation requires 263 piles, and the bored pile foundation requires 258 piles.
6
Ding, Zu De, Li Min Peng, and Cheng Hua Shi. "Numerical Analysis of Deformation Effect on Adjacent Piles Due to Excavation." Applied Mechanics and Materials 256-259 (December 2012): 1258–62. http://dx.doi.org/10.4028/www.scientific.net/amm.256-259.1258.
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Combined with the project of an open cut metro tunnel passing through a viaduct, three- dimensional finite element method is applied to study the lateral deformation law of viaduct pile foundations induced by adjacent excavation in the pile foundations reinforcement and un-reinforcement conditions. The results show that the lateral deformation of pile foundations increases with the increasing of excavation depth. The closer distance and the larger deformation, the influence of pile foundations on excavation will be more obvious. The pile foundations deformation is significantly reduced when taking protection measures such as adding new piles, expanding the pile cap and strengthening stratum. Compared with the maximum deformation of the un-reinforcement condition, the reinforcement condition is only 27% to 30%, and the reinforcement measure is remarkably effective. In addition, the length of the piles, the depth of foundation pit, as well as the relative positions of walls and piles have significant influences on piles deformation forms, and it should be taken into account in the design and construction of foundation pit.
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Ahmed, Huda Hussein, and Salah Rohaima Al-Zaidee. "Experimental Investigation for Effects of Mini-piles on the Structural Response of Raft Foundations." Civil Engineering Journal 5, no. 5 (May 21, 2019): 1084–98. http://dx.doi.org/10.28991/cej-2019-03091313.
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Mini-piles made their debut as a cost-effective way to stabilize the historical structures. Recently, mini-piles have increased in popularity all over the world and are being used for bridges, buildings, slope stability, antenna towers, and residential construction. This paper presents the preparing, executing, data acquisition, and result presentation for an experimental work concerns with five scale-down mini-piled raft foundation models. All models were prepared to study the effectiveness of the mini-piled raft foundation in reducing the settlement and the bending moments. Five tests have been achieved. The reference first test includes a raft foundation with 15mm thickness. Second, third, and fourth tests are mini-piled raft foundations with five mini-piles and with thicknesses of 15 mm, 10 mm, and 8mm respectively. Finally, the fifth test dealt with a single mini-pile 178mm in length and 6mm in diameter. It has been adopted to investigate the reference behavior of the single mini-pile. When they were used, the piles have 42 mm center to center distances. A scale-down factor of , a sandy soil with with of , and relative density of 60% have been considered in all tests. Test results indicated a 45% decrease in settlement for 15mm mini-piled raft foundation comparing with the reference 15mm raft foundation. Moreover, there is no significant difference in settlement between 15mm mini-piled raft foundation comparing with the 10mm and 8mm thick mini-piled raft foundations. Regarding to the bending moments, they decrease at the mid and edge of the 15mm mini-piled raft foundation comparing to those of the reference raft foundation. It has also been noted that the moments are inversely proportional to the thickness of the piled raft foundations. With respect to the mini-piles, it has been found that most of the pile axial loads are transferred to the underneath soil through friction and this friction increases as the raft thickness decreases.
8
Bralović, Nemanja, Iva Despotović, and Danijel Kukaras. "Experimental Analysis of the Behaviour of Piled Raft Foundations in Loose Sand." Applied Sciences 13, no. 1 (December 30, 2022): 546. http://dx.doi.org/10.3390/app13010546.
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This paper presents the experimental analysis that was conducted on small-scale 1g physical models of piled raft foundation structures with a group of 2 × 2 piles in loose sand. The purpose of the piles was to reduce the settlement of the raft. The test program included twelve experiments, three of which were conducted on a raft alone and nine on piled rafts at pile distances of 3d, 4d, and 5d and pile lengths of 10d, 20d, and 40d, where d is pile diameter. The test results show that the current conventional approach to design of piled raft foundations, at a high safety load factor in piles that assume to take the whole external applied load, is very conservative. Instead, it is more economical to apply a low bearing capacity factor for piles as settlement reducers and maximize use of raft bearing capacity to carry part of the external load.
9
Cui, Kai, Jun Feng, and Chengyong Zhu. "A Study on the Mechanisms of Interaction between Deep Foundation Pits and the Pile Foundations of Adjacent Skewed Arches as well as Methods for Deformation Control." Complexity 2018 (2018): 1–19. http://dx.doi.org/10.1155/2018/6535123.
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The construction of deep foundation pits is characterized by heavy loads on pile foundations, complex interactions between the foundation pit and pile foundations, and stringent requirements for deformation control. In this work, FLAC3D was used to perform computational analyses on the displacement responses of pile caps and the retaining walls of foundation pits in a variety of cases and reinforcement schemes. The computational results indicate that the piles of skewed arches interact with the retaining walls of the foundation pits through soil masses. We also revealed the mechanism by which deep foundation pits interacted with the pile foundations of adjacent skewed arches. Based on the mechanisms of interaction between foundation pit excavations and the piles of skewed arches, we proposed three reinforcement schemes for controlling the deformations associated with these interactions. The arched wall reinforcement scheme could provide a satisfactory result in terms of the control of horizontal displacements in the pile foundations and project costs.
10
de Freitas Neto, Osvaldo, Renato P. Cunha, Olavo Francisco Santos, Paulo J. R. Albuquerque, and Jean R. Garcia. "Comparison of Numerical Methods for Piled Raft Foundations." Advanced Materials Research 838-841 (November 2013): 334–41. http://dx.doi.org/10.4028/www.scientific.net/amr.838-841.334.
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The methodologies used to calculate piled raft foundations are normally more complex than conventional foundations due to the large number of variables involved in the problem. In the conventional block, the interaction variables considered are only between the pile and the soil. In the piled raft, all the interaction effects must be considered, as follows: plate-soil, plate-piles and piles-soil, simultaneously. The Finite Element Method (FEM) has proven to be a useful tool in analyzing these types of problems. This study aims at assessing the behavior of piled rafts using the Cesar-LCPC numerical tool, version 4.0, which is based on the finite element method. Literature cases of rafts supported by 9, 15 and 16 piles were analyzed. The results obtained were compared with analysis methods presented in the bibliography. The following parameters were assessed: relative spacing (S/D), relative length (L/D), relative stiffness between piles and the soil (KPS), and settlement of piles and the raft. The spacing between piles has a significant influence on load distribution between piles and the raft. Very small spacing provides stiffness to the foundation, which then functions as a conventional pile foundation, in which only the piles absorb the load from the superstructure. The larger the L/D ratio, the lower the settlement and for a given modulus of elasticity of the pile, the increase in relative stiffness (KPS) causes an increase in settlement. In all analyses, the data obtained corroborated the results presented by other methods published in the literature.
11
Xie, Yunfei, and Shichun Chi. "Optimization Method of Reducing the Differential Settlements of Piled Raft Foundations Based on Pile-to-Pile Interaction Theory." Advances in Civil Engineering 2020 (August 10, 2020): 1–14. http://dx.doi.org/10.1155/2020/1521876.
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In order to reduce the differential settlement of piled raft foundations, an optimization method based on pile-to-pile interaction theory is proposed in this paper, which translates the problem of pile-to-pile interaction (PPI) in pile groups into that in single piles using the interaction factor method. The pile lengths were adjusted via the relationship between load, settlement, and the length of single piles during the optimization design. ANSYS software, in conjunction with nonlinear elastic soil model, is used to analyze piled raft foundation models. Two cases with different safety factors that suffer different kinds of surface loads (uniform load and nonuniform load) are used to verify this method. The differential settlements of the raft in different cases are all reduced by nearly or more than 80% after optimization design. The results show that the optimization method proposed in this paper has high efficiency and stability. This study can help practicing engineers optimize the pile lengths in pile groups to satisfy higher differential settlement requirements.
12
Rahman, Arief, Ferry Fatnanta, and Syawal Satibi. "Analysis of the capability of pile assembly foundations in soft soil in physical modeling of variationsiin laboratory scale distances." astonjadro 12, no. 1 (January 4, 2023): 136. http://dx.doi.org/10.32832/astonjadro.v12i1.8139.
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<p>The capacity of raft foundations, pile foundations and pile rafts on soft soil with variations in the distance between the piles. Perform analysis of the carrying capacity and settlement of each foundation test and then compare the results of the theoretical carrying capacity research with the analysis of carrying capacity calculations. The implementation of the test prepares the test along with samples of the raft foundation, pile foundation and pile raft foundation. The test were carried out using a gradual load then a dial gauge is placed at both ends of the sample raft and the load reading is taken. The pile foundation was tested with a decrease of 10 cm while the settlement on the raft foundation and the pile raft foundation was 3 cm, the carrying capacity of the raft foundation was 24 kg, the pile foundation varied 4D distances; 6D and 8D, namely 7.5 kg and the foundation of the pile raft with variations in 4D distance; 6D and 8D are 26 ; 32 and 32 kg. In the interpretation method, the pile raft foundation with various distances increased from 4D to 6D but decreased in 8D. Pile raft foundations with various distances between pile have not a significant effect where raft foundations are more dominant in supporting resistance than pile foundations.</p>
13
Ahmed, Danish, Siti Noor Linda Bt Taib, Tahar Ayadat, and Alsidqi Hasan. "A Review on the Behaviour of Combined Stone Columns and Pile Foundations in Soft Soils when Placed under Rigid Raft Foundation." ASM Science Journal 16 (July 15, 2021): 1–8. http://dx.doi.org/10.32802/asmscj.2021.709.
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In the last few decades, it has been observed that raft foundations are very commonly used as a foundation solution for moderate to high rise structures either by resting on stone columns or on piles in soft soils. It is believed that, combining stone columns and piles in one foundation system is the more suitable foundation for medium rise structures. The combined foundation system provides a superior and more economical alternative to pile, and a more attractive alternative to stone columns in respect to ground improvement. This paper presents the review of existing studies reported in the literature in the last two decades about the behaviour of stone columns under raft foundations and piled raft foundation in soft soil, notably the failure mechanism and the bearing capacity. Also, a limited work from the literature concerning the performance of combined (pile/stone columns) foundation system in soft soil is comprised. Furthermore, very extensive ongoing research work regarding the investigation and study on the performance of combined (pile/stone columns) foundation system in soft soils is discussed. The main goals and methodology to study the performance of the combined (pile/stone columns) foundation systems in soft soil are also addressed.
14
Xie, Yunfei, and Shichun Chi. "Optimization Method for Irregular Piled Raft Foundation on Layered Soil Media." Advances in Civil Engineering 2019 (May 20, 2019): 1–15. http://dx.doi.org/10.1155/2019/5713492.
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Important buildings such as nuclear power plants always require stricter control of differential settlement than ordinary buildings. Therefore, it is necessary to provide an optimized design for the piled raft foundations of important buildings. In this paper, a new optimization method (using different pile diameters and different pile spacing) was proposed for the design of piled raft foundations. This method adjusts the pile diameters and pile spacing according to the stress distribution at the pile top of the initial design to achieve a more uniform settlement of the raft and stress distribution on top of piles, which can solve the differential settlement problems caused by uneven loads of the superstructure. After optimized design, the differential settlement and integral bending moment of the raft decreased more than 64% and 52%, respectively, and the differential stress on top of piles decreased by at least 63%. The new method proposed in this paper could be applied to large-scale piled raft foundations with complex superstructure loads.
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Omer, Joshua, and Hasan Haroglu. "Tests on Model Piled Rafts in Sand: Measured Settlements Compared with Finite Element Predictions." Geotechnical and Geological Engineering 39, no. 4 (February 2, 2021): 3271–83. http://dx.doi.org/10.1007/s10706-020-01664-0.
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AbstractLaboratory tests were carried out on non-piled rafts, single piles, surface contacting and non surface-contacting piled rafts which were made of aluminum and instrumented with strain gauges and deflection gauges. The foundations were installed in dry sand contained in a large metal tank to minimize boundary effects. Maintained loads were applied to each foundation until failure was closely approached. In parallel, analyses were performed using PLAXIS™ 3-D finite element program to compare the calculated and measured load-settlement trends hence assess the influence of soil stiffness on the foundation behaviour. The results confirmed that group efficiency of non-surface contacting piled increased with increasing pile–pile spacing and approached unity at a spacing equivalent to 8D (D = pile diameter). The data obtained from the strain gauges provided valuable insight into the load-transfer characteristics of different foundations and subsequently proved that the capacity of a surface contacting piled raft is significantly enhanced compared to that of either a non-piled raft or a non-surface contacting piled raft.
16
Fellenius, Bengt H. "Observations and analysis of wide piled foundations." Canadian Geotechnical Journal 56, no. 3 (March 2019): 378–97. http://dx.doi.org/10.1139/cgj-2018-0031.
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Available case histories on observations on full-scale piled rafts show that the settlement response to applied load can be modeled as that for an Equivalent Pier due to compression of the piles and the soil matrix plus that of an Equivalent Raft for compression of soil layers below the pile toe level. Interior piles engage the soil from the pile toe level upward in contrast to a single pile, which engages it from the ground downward. Piles and soil, combined as a pier, have strain compatibility, which determines the distribution of load between the piles, the contact stress, and the load-transfer movement of the piles. The responses between the interior and perimeter piles differ. Particularly so in non-subsiding and subsiding environment, because perimeter piles can be subjected to downdrag and drag forces, while neither downdrag nor drag force will affect the interior piles. In non-subsiding environment, it is advantageous to make perimeter piles shorter, while in subsiding environment perimeter piles best be longer. The load distribution across the raft is also governed by the degree of rigidity of the raft and by the difference in dishing at the pile toe level and in the dishing of the actual raft.
17
Shakirov, Ildus. "Bearing capacity of piles in a reinforced by pressure cementation soil massif." E3S Web of Conferences 274 (2021): 03023. http://dx.doi.org/10.1051/e3sconf/202127403023.
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Studies of the piles bearing capacity after strengthening soil by cement mortar pressure injection were carried out to determine pile foundations bearing capacity increasing patterns in a result of soils cementation. Depending from the volume and cement mortar technological injection parameters, the soil stress state around the pile changes, additional pile-soil compression occurs and the friction along the lateral surface increase, as well as the soil resistance under the pile bottom end. Cementation effect on the pile bearing capacity for different injectors location and the number of piles in the foundation were determined by tests. The research results can be used in the pile foundations reinforcement design in conditions of reconstruction with increasing loads on the foundations.
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Zhou, Ke Feng, and Yu Zhi Li. "Computer Modeling for the CFG Pile in Highway Soft Foundation." Applied Mechanics and Materials 84-85 (August 2011): 421–25. http://dx.doi.org/10.4028/www.scientific.net/amm.84-85.421.
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In past 10 years, composite foundations, especially multipile composite foundations have been extensively used. Multi-pile composite foundation is a method of ground improvement that involves using different pile types with different lengths and diameters beneath the same raft. The CFG piles are generally much stiffer than lime piles and they are used in a manner similar to that used for conventional piles; that is, to mobilize bearing capacity from the deeper soil strata. This paper presents the results of a series of three dimensional (3D) finite element analyzes on CFG–lime composite pile foundations. The parameters investigated are the spacing of CFG pile and cushion thickness.
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Kravchenko, Pavel, Maxim Paramonov, Konstantin Slivets, and Sergey Metelkin. "Methodology for calculating the settlement of pile-raft foundations and foundations strengthened with piles." E3S Web of Conferences 371 (2023): 02021. http://dx.doi.org/10.1051/e3sconf/202337102021.
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In the case of using pile technology in the construction and reconstruction of buildings and structures, the issue of assessing the settlement of foundations arises quite sharp-ly. Modern regulatory documents do not reflect reliable methods for calculating the settlement of pile-raft foundations, especially if short piles are used (with a pile length of 3-10 m). The ar-ticle provides a calculation methodology that makes it possible to assess the settlement of foundations, taking into account the distribution of loads between the piles and the raft (strengthened foundation), not only for cases of pile-raft foundations with a low raft, but also for cases of strengthening existing foundations with piles. The proposed technique allows the use of standard (including those reflected in the normative documentation) methods for calcu-lating the settlement, resulting in deformations close to the real ones.
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Gao, Yong Tao, Qing Liang Wu, Shun Chuan Wu, Mao Wei Ji, Ai Ping Chen, and Chen Ye Wan. "Numerical Analysis of Tunneling Influence on Settlement of Existing Pile Foundations Based on Orthogonal Design." Applied Mechanics and Materials 170-173 (May 2012): 1419–26. http://dx.doi.org/10.4028/www.scientific.net/amm.170-173.1419.
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Because of the Limited urban space and the development of transport, underground space development, especially the metro construction, is vigorously developed in many cities. Subway passing through the existing building inevitably may cause the settlement and deformation of the buildings and their foundations. Therefore, research on the influence of tunneling on existing buildings has important significance. In order to study the influence of tunneling on settlement of existing pile foundations, soil elastic modulus, cohesion, friction angle, tunneling sizes, distance between tunnel opening boundaries and existing pile foundation etc. are discussed as analysis factors in this paper. The calculation schemes are designed based on orthogonal design, and then the influence of tunneling on existing buildings is researched according to the numerical calculation model which is established by the finite element software. Finally, the sensitivity of pile foundation settlement to various factors is analyzed according to the results of simulation analysis. we can draw the conclusions: the influence of tunneling on settlement of existing pile foundation is positively correlated with tunneling sizes, and is negatively correlated with soil parameters and distance between tunnel opening boundaries and existing pile foundations; The settlement of pile foundations can be effectively controlled by application of composite anchor isolation piles around the existing buildings piles, but with the increase of soil parameters and distance between tunnel opening boundaries and existing pile foundations, the strengthening effects are decreased; soil elastic modulus and excavation sizes are the key impact-factors of pile settlement within the distance of 5m between tunneling boundaries and existing pile foundations, which have extremely remarkable effect on the subsidence of pile foundations.
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Kannaujiya, Pratish, and Vijay Kumar Srivastava. "Behavior of Different Configuration of Piled Raft Foundation for a High-Rise Building by using FEM." IOP Conference Series: Materials Science and Engineering 1236, no. 1 (April 1, 2022): 012006. http://dx.doi.org/10.1088/1757-899x/1236/1/012006.
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Abstract In this paper, the numerical simulation is performed on two piled raft configurations having uniform loading on a piled raft foundation. To investigate the interaction between various parameters of pile soil foundation with varying components of its length of pile, diameter and raft thickness. These components are critical for increasing the foundation’s bearing capacity. It’s important aspect to achieve a reliable design to optimize piled raft foundations subjected to uniformed load- settlement behaviors of the curves. These load – settlements are basically depending on the changing of their components piled raft foundation. These component of piled raft foundations to choose an optimal selection of embedded length of pile (L/dP), normalized diameter of pile (L/dP) and normalized raft thickness (tR/dP). The effect of load-settlement on distributions of shear force and bending moments is also investigated. In this study, a finite elements methods based on numerical tools ELPLA software is used for numerical simulation. The study’s findings validate the numerical analysis for the calculation of proper pile configuration arrangement, as a result of settlements. It will be generated as formation of contours patterns as shear stress and bending moments on the rafts, may be minimized with the total pile length. The conclusion drawn from the study validates the numerical analysis for the computation of proper pile arrangement can results in total and differential settlements, as well as generated shear stress and bending moments on the rafts, are all being reduced, with identical total pile length. Moreover, it captures the contours patterns of different behaviors of piled raft settlements, maximum shear force and maximum moments.
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Zhou, Mingru, Lijun Xing, Yiming Chen, and Hongxia Qiao. "Settlement Characteristics of Split Grouting Pile Composite Foundation in Loess Areas." Advances in Civil Engineering 2022 (November 23, 2022): 1–14. http://dx.doi.org/10.1155/2022/8627124.
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Loess foundations often affect the stability of superstructures due to their insufficient bearing capacities; thus, reinforcement measures are crucial for mitigating the uneven settlement of foundations. This study aims to investigate the settlement characteristics of composite foundations for loess foundations reinforced by splitting grouting piles. First, split grouting tests were carried out on loess foundations. After the test piles reached the design strength, static load tests and geotechnical tests were carried out to obtain the Q-s curves of the test piles. The pile-forming mechanism was analyzed via excavations at an on-site test pile. Furthermore, the traditional settlement calculation method of composite foundations was used to calculate the settlement of split grouting pile composite foundations, and the results were compared with field test results to explore a suitable settlement calculation method of split grouting pile composite foundations. Finally, the numerical model of split grouting pile composite foundations was established according to the pile forming mechanism, and the settlement deformation characteristics of single pile and pile group composite foundations were analyzed. The relative errors of the composite modulus method and the stress correction method for calculating the settlement of the composite foundations were 6.4% and 32.8%, respectively, and the composite modulus method was closer to the test values. The calculated curves of the numerical model were in good agreement with the measured curves and relevant literature research results, demonstrating the rationality of the modeling method; the findings of this study provide theoretical guidance for designing loess foundation splitting grouting reinforcement and for predicting settlement during later construction periods.
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Yuan, Chenyang, Yunfei Xie, and Mang Ou. "Adaptive Optimization Method for Piled Raft Foundations Based on Variable Pile Spacing." Applied Sciences 13, no. 3 (January 28, 2023): 1648. http://dx.doi.org/10.3390/app13031648.
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Stricter control of the differential settlement is always required in important buildings more than in ordinary buildings. It becomes a necessity to find a simple and efficient optimum design method for pile foundations in terms of performance and economy. In this paper, an adaptive optimization method (AOM) is proposed to reduce the differential settlement of the pile group and piled raft, in which the piles are located in appropriate locations according to the settlement characteristic of the raft. Piled raft foundations with different types of load and different raft shapes are optimized using this method; soil inhomogeneity and nonlinear characteristic are considered during this process. The optimization results show that the reductions of the differential settlement are more than 80%. The overall foundation performances are improved as the maximum settlements of the foundations are reduced. The maximum bearing capacity of the pile group is no more than its ultimate bearing capacity after optimization design, and part of the excess bearing capacity can be translated into economic savings (AOM-ES). By keeping a good optimization effect of the differential settlement, the number of piles can be reduced by AOM-ES compared with the initial design. The AOM is robust and can be applied to the piled foundations of various raft shapes in layered soils under complex vertical loads with no significant impact on optimization efficiency.
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Wu, Chuan-Sheng, Man Ge, Ling-Ling Qi, De-Bing Zhuo, Jian-Qiang Zhang, Tian-Qi Hao, and Yang-Xia Peng. "Multi-Defect Identification of Concrete Piles Based on Low Strain Integrity Test and Two-Channel Convolutional Neural Network." Applied Sciences 13, no. 6 (March 9, 2023): 3530. http://dx.doi.org/10.3390/app13063530.
Full textAbstract:
Defects in different positions and degrees in pile foundations will affect the building structure’s safety and the foundation’s bearing capacity. The efficiency and accuracy of using traditional methods to identify multi-defect types of pile foundations are very low, so finding suitable methods to improve their related indicators for pile foundation safety and engineering applications is necessary. In this paper, under the condition of secondary development of finite element software ABAQUS to obtain the time-domain signal database of six kinds of multi-defect pile foundations, a multi-defect type identification method of pile foundations based on two-channel convolutional neural network (TC-CNN) and low-strain pile integrity test (LSPIT) is proposed. Firstly, simulated time-domain signals of the dynamic measurements that match the experimental results performed wavelet packet denoising. Secondly, the 1D time-domain signals before and after denoising and the corresponding 2D wavelet time–frequency maps are inputs to retain more data information and prevent overfitting. Finally, TC-CNN achieved the multi-defect type identification of concrete piles. Compared with the single-channel convolutional neural network, this method can effectively fuse 1D and 2D features, extract more potential features, and make the classification accuracy reach 99.17%.
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Fioravante, Vincenzo, and Daniela Giretti. "Contact versus noncontact piled raft foundations." Canadian Geotechnical Journal 47, no. 11 (November 2010): 1271–87. http://dx.doi.org/10.1139/t10-021.
Full textAbstract:
In the last few decades there has been a rapid increase in the number of piled foundations where the piles have been employed as settlement reducers; in some recent projects, the piles have been separated from the raft by a granular layer, which creates a more uniform pressure distribution on the raft bottom and reduces constraint reactions in the soil, foundation, and superstructure. A series of centrifuge model tests has been performed to investigate the load transfer mechanisms between a square rigid raft and a group of instrumented piles jacked in dry dense sand, in direct contact with the raft or separated from the raft by an interposed granular layer. The test results have shown that contact piles act as settlement reducers by diffusing the load applied to their heads to greater and deeper volumes of soil. The insertion of a deformable layer between a raft and pile heads does not ensure displacement compatibility, and the pressure diffused by the granular fill acts partly on the pile heads and partly produces shallow soil settlements, which mobilize negative skin friction on the upper part of the pile shaft. Noncontact piles act mainly as soil reinforcement.
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Zhu, Bin, Kai Wen, Tao Li, Lujun Wang, and Deqiong Kong. "Experimental study on lateral pile–soil interaction of offshore tetrapod piled jacket foundations in sand." Canadian Geotechnical Journal 56, no. 11 (November 2019): 1680–89. http://dx.doi.org/10.1139/cgj-2018-0292.
Full textAbstract:
Recently, tetrapod piled jacket (TPJ) foundations have shown considerable promise in offshore developments, due to the increases in power capacity and water depth for offshore wind turbines. This paper presents a set of centrifuge tests to look into the lateral loading behaviour of TPJ foundations in sand, with the overall load–displacement responses of the foundation as well as the soil resistance and internal forces on or within individual piles being examined carefully. Test results show that the back-row piles are more likely to be pulled out when the TPJ foundation is loaded laterally along the diagonal direction compared to when loaded along the orthogonal direction. The lateral soil resistance per unit length on the back-row pile(s) is approximately 60% of that on the front-row one(s) in the orthogonal loading case, and only about 40% in the diagonal loading case. Moreover, although the TPJ foundation is in its form a special case of pile groups, it is highlighted in the present study that the former case exhibits distinct loading behaviour from the latter case due to the typically large overturning moment encountered by the foundations for offshore wind turbines. Finally, the p-multipliers of the piles are demonstrated to be dependent on pile deflections, but independent on soil depths, and as a result, a modified pm model is proposed to provide guidance for the design of TPJ foundations in sand.
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T, Aruna, K. V. S. B. Raju, and Swathi Gowda. "Experimental Investigation of piled raft foundation on Cohesionless Soil." International Journal of Research and Scientific Innovation 09, no. 02 (2022): 113–18. http://dx.doi.org/10.51244/ijrsi.2022.9207.
Full textAbstract:
The combination of piles and raft foundation is known as piled raft foundation. Piled raft foundations have proven to be more cost-effective and capable of meeting safe bearing capacity and serviceability norms in the case of high-rise buildings on cohesionless soil. The behavior of a stacked raft foundation is influenced by the piles, raft, and soil. The stacked raft system’s bearing capacity is improved and settlement is minimized when the ground beneath the raft foundation bears the burden of supporting the applied loads. The piled raft foundation minimizes total settlement and improves bearing capacity more than the raft foundation. When isolated footings cover more than 70% of the building area under a superstructure, raft foundations are used, and the present study focuses on the vertical load bearing capability of piled raft foundation systems on cohesionless soil for concentric loading. The use of strategically positioned piles increases the load capacity of the raft while reducing differential settlement. The present study sheds some light on the use of piles as raft foundation settlement reducers, as well as the behavior of a piled raft in sand. A series of small-scale model experiments were carried out. The present investigation studies by varying pile length and alignment on the ultimate load of piled raft foundation. The results indicate that for a 10mm raft thickness, installing 4 piles, 6 piles, and 9 piles by varying L/D ratios of 5,10,15,20 carries significant load. In this present work for a 50mm length of pile, and the value of load improvement ratio increases by 36 percent, 60 percent, and 68 percent, respectively, when compared to plain raft.
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Yu, Enbo, Sen Ren, Haojun Tang, Yongle Li, and Chen Fang. "Improvement on Structural Forms of Pile Group Foundations of Deepwater Bridges." Shock and Vibration 2019 (August 14, 2019): 1–15. http://dx.doi.org/10.1155/2019/7381852.
Full textAbstract:
As long-span cross-sea bridges extend to deeper sea areas, the bridge pile tends to increase in its slenderness ratio and becomes more susceptible to waves. To improve the structural stability at the construction stage, this study analyses wave-induced response of foundations. The wave theory and the method used for computing wave forces on foundations are first introduced. Then, a pile group foundation is taken as the research object, and different pile lengths ranging from 16 m to 46 m are considered. The wave-induced response of the piles and the cap is calculated. After understanding the effect of the pile length, three optimized foundations are proposed with the aim of reducing the free length of the pile, and the corresponding finite element models are established to compare their wave-induced response. The results show that the displacement at the top of the foundation increases with the increase in the pile length until the cap partly emerges from water and so does the internal force at the bottom. Setting a constraint in the middle of the piles can reduce their free lengths and is favourable to the wave-induced response of the foundation except for the shearing force. A stronger constraint shows better effects on improvement of the stability of the foundation. The conclusions provide reference for optimization on pile foundations of deepwater bridges.
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Jamil, Irfan, Irshad Ahmad, Wali Ullah, Mahmood Ahmad, Mohanad Muayad Sabri Sabri, and Ali Majdi. "Experimental Study on Lateral and Vertical Capacity of Piled Raft and Pile Group System in Sandy Soil." Applied Sciences 12, no. 17 (September 2, 2022): 8853. http://dx.doi.org/10.3390/app12178853.
Full textAbstract:
In deep foundations, the pile group and the pile raft are generally used. To date, the contribution of the raft is not taken into account in the design, even when the raft is in contact with the soil and the whole system is therefore considered to work as a pile group foundation. In a combined pile raft system, the raft takes a considerable portion of the applied load, depending upon the number of piles, the spacing to diameter ratio of the piles, and the length to diameter ratio. In this paper, an experimental investigation is carried out to study the response of small-scale pile group and piled raft models with a varying number of piles subjected to both vertical and lateral loads. Additionally, the response mechanism of these models to both types of loads is also studied. A comparison was made between these models. It was found that, unlike the pile group, the piled raft provides considerably high stiffness to both types of loads, and the difference between the stiffness of both systems decreases as the number of piles increases. By comparing the response of the piled raft and the pile group with the same number of piles under the same vertical and lateral load, it was concluded that the piled raft response to the lateral and vertical loads was much stiffer than the pile group response. The lateral deflection and the vertical settlement of the piled raft were less than those of the pile group with the same pile configuration. This effective response of the piled raft to the vertical and lateral loads was due to the raft contribution in resisting the vertical and lateral loads. Moreover, with the increase in the number of piles, the vertical and lateral contribution of the raft decreases.
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Li, Zheming, Malcolm D. Bolton, and Stuart K. Haigh. "Cyclic axial behaviour of piles and pile groups in sand." Canadian Geotechnical Journal 49, no. 9 (September 2012): 1074–87. http://dx.doi.org/10.1139/t2012-070.
Full textAbstract:
Piled foundations are often subjected to cyclic axial loads. This is particularly true for the piles of offshore structures, which are subjected to rocking motions caused by wind or wave actions, and for those of transport structures, which are subjected to traffic loads. As a result of these cyclic loads, excessive differential or absolute settlements may be induced during the piles’ service life. In the research presented here, centrifuge modelling of single piles and pile groups was conducted to investigate the influence of cyclic axial loads on the performance of piled foundations. The influence of installation method was investigated and it was found that the cyclic response of a pile whose jacked installation was modelled correctly is much stiffer than that of a bored pile. During displacement-controlled axial load cycling, the pile head stiffness reduces with an increasing number of cycles, but at a decreasing rate; during force-controlled axial load cycling, more permanent settlement is accumulated for a bored pile than for a jacked pile. The performance of individual piles in a pile group subjected to cyclic axial loads is similar to that of a single pile, without any evident group effect. Finally, a numerical analysis of axially loaded piles was validated by centrifuge test results. Cyclic stiffness of soil at the base of pre-jacked piles increases dramatically, while at base of jacked piles it remains almost constant.
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Darjanto, Helmy. "FLOATING RAFT-PILE FOUNDATIONS ANALYSIS USING NUMERICAL SIMULATION." Jurnal Rekayasa Sipil (JRS-Unand) 7, no. 2 (October 15, 2011): 40. http://dx.doi.org/10.25077/jrs.7.2.40-46.2011.
Full textAbstract:
The numerical simulation of raft-pile foundations subjected to vertical load is presented in this paper. For comparison study, numerical models of single raft and pile groups are completed. The numerical models are adopting the elastic constitutive law for the materials. The stresses and
vertical displacement of the models are observed. The behaviour of the raft-pile foundation compared to the pile-group is then investigated. The results using the same external load show that the raft-pile foundation has smallest displacement compared to the others. In terms of stresses, the
raft shows contribution of the load transfer to the underneath soil as well as the piles. Moreover, the behaviour of the raft-pile system appears to be a combination of the pile-group and the single raft. In order to estimate the bearing capacity of the raft-pile system, it is suggested that the contribution of the raft should be included in addition of the piles’.
Keywords: raft-pile foundation, soil-structure interaction, floating foundation
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Leung, C. F,, C. W. Ong, and K. Y. Yong. "Effect of Tunneling on Adjacent Piled Foundation in Clay." Journal of Civil Engineering and Construction 8, no. 1 (February 15, 2019): 19–24. http://dx.doi.org/10.32732/jcec.2019.8.1.19.
Full textAbstract:
Soil movements arising from tunnel excavation may induce severe stresses on adjacent piled foundations. This paper investigates the behavior of piles due to nearby tunneling in soft clay using centrifuge modeling technique. Centrifuge modeling has an advantage that the consolidation time of the clay under forced gravity field can be expedited significantly to study the long term performance of a pile due to tunneling. The types of piles investigated in the present study include floating pile, socketed pile and end bearing piles with different pile head conditions. The test results on the induced axial and lateral pile responses due to tunneling are presented in this paper and the implications of the findings to engineering practice are highlighted.
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Cunha, Renato P., and Ary F. Cordeiro. "Numerical Assessment of an Imperfect Pile Group with Defective Pile both at Initial and Reinforced Conditions." Soils and Rocks 33, no. 2 (May 1, 2010): 81–93. http://dx.doi.org/10.28927/sr.332081.
Full textAbstract:
The assessment of problems of imperfect, damaged, pile groups is scarce in the geotechnical literature. Besides, techniques of assessing the performance of the foundation system once a defect is found are seldom presented, as well as real examples of the behavior of large scale imperfect foundations after their remediation. Therefore, this paper has extended the design philosophy of “piled raft” foundations to predict the numerical behavior of imperfect pile group foundations at pre and post-remediated conditions. Focus will be given to the problem of groups with either defective shorter length or lower stiffness piles, caused by natural or man-made sources. The remediation of the group is considered via added reinforcement piles with either similar or dissimilar characteristics (length, diameter, stiffness) compared to the original undamaged piles. Although the results are limited, they allow preliminary generalizations of the overall group behavior at working conditions, once a pile flaw is noticed and after the remediation has taken place. Among other results the paper highlights the load sharing mechanism between foundation elements, which relates to the position and magnitude of damage of the defective pile, as well as to the overall characteristics of reinforcement one. It was concluded that a defect caused by an unwanted pile length variation can be more detrimental to the foundation system than an unexpected low structural stiffness for the constructed pile. The derived factor of safety (SF) of the system (overall value) and of its distinct components (individual values) are also influenced by aforementioned variables, leading to questions on how the reinforcement can be made in such manner to obtain well optimized SFs. As noticed throughout the analyses, defective piles share its load with system components, once a defect appears. Nevertheless, even when imperfect such piles continue to absorb some load, although to a lesser degree than the original value. The reinforcement piles tend to absorb (or retain) some of the load spread by the defective ones, in a proportion which depends to its general characteristics (size, position, stiffness). Again, questions about an optimization procedure have to be made in order to wisely and economically use this particular observed feature on the remediation design.
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Naghibi, Farzaneh, and Gordon A. Fenton. "Target geotechnical reliability for redundant foundation systems." Canadian Geotechnical Journal 54, no. 7 (July 2017): 945–52. http://dx.doi.org/10.1139/cgj-2016-0478.
Full textAbstract:
Geotechnical support systems (e.g., deep and shallow foundations) generally involve at least some redundancy. For example, if a building is supported by np separate foundations, then failure (e.g., excessive settlement) of a single foundation will generally not result in failure of the building if the building is able to shed the load from the failed foundation to adjacent foundations. This load-shedding ability lends the foundation system redundancy — system failure only occurs if multiple foundations fail. This paper investigates the relationship between the level of geotechnical redundancy, individual foundation reliability, and system reliability for deep foundations (piles). In the particular case where the pile resistance remains constant after achieving its ultimate capacity (at a certain displacement), the relationship between individual and system reliabilities is computed theoretically. The more general case, where the load carried by the pile reduces after exceeding its ultimate capacity, is investigated by Monte Carlo simulation. Charts relating system and individual reliability indices are presented, which can be used to aid in the design of individual piles as part of a pile support system.
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Guo, Yuancheng, Chenyu Lv, Siqiang Hou, and Yunlong Liu. "Experimental Study on the Pile-Soil Synergistic Mechanism of Composite Foundation with Rigid Long and Short Piles." Mathematical Problems in Engineering 2021 (May 4, 2021): 1–15. http://dx.doi.org/10.1155/2021/6657116.
Full textAbstract:
The rigid long-short-pile composite foundation has been increasingly used as an effective and low-cost reinforcement method. The pile-soil interaction in this foundation type is more complicated than that in the equal-length pile composite foundation. In this study, several physical model tests were conducted to investigate the pile-soil synergistic mechanism of the rigid long-short-pile composite foundation. A comparative analysis was conducted of the static load test data of single-pile and long-short pile composite foundations to assess the load-bearing characteristics and stiffness evolution of the composite foundation and pile-soil unit. The result indicated a positive correlation between the pile length and the overall bearing capacity of the single-pile composite foundation. The overall stiffness of the four-pile composite foundation was lower than that of the single-pile composite foundation due to an increase in the areas of the soil stress and the pull-down effect caused by multiple piles. The long pile exerted a greater influence on the overall settlement than the short pile. In addition, the correction coefficients were obtained to determine the pile-soil stiffness of the four-pile composite foundation based on that of the single-pile composite foundation, providing a theoretical reference for the optimal design of composite foundations.
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Qiu, Hongsheng, Yihui Zhou, and Mo’men Ayasrah. "Impact Study of Deep Foundations Construction of Inclined and Straight Combined Support Piles on Adjacent Pile Foundations." Applied Sciences 13, no. 3 (January 31, 2023): 1810. http://dx.doi.org/10.3390/app13031810.
Full textAbstract:
An inclined straight combination support pile can play a better role in deep foundation pit support, especially for the protection of adjacent structural pile foundations. We take a section of the construction of a deep foundation pit project in Wuhan City, Hubei Province as the research object. This paper studies the influence of inclined and straight combination support piles on the bending moment and displacement behavior of adjacent pile foundations during the construction of foundation pits under the influence of different factors such as distance from the excavation surface, pit angle effect, inclined pile tilt angle, pit depth to width ratio, and construction conditions on the adjacent pile foundation using a three-dimensional finite element model. According to the research results, as the distance from the excavation surface increases, the bending moment of the adjacent pile foundation decreases, and the closer the pile is to the foundation pit, the greater the horizontal displacement of the pile; the bending moment and displacement of the pile foundation are supported by the pit angle effect. Moreover, the pile bending moment increases with the increase of the pit depth–width ratio, and the maximum displacement point of the pile body gradually moves down from the middle of the pile body to the bottom of the pile foundation as the excavation depth of the pit increases. In addition, the minimum displacement of the adjacent pile foundation is at the top of the pile, and the maximum displacement is at the middle of the pile. Finally, compared with the static analysis, the whole process of dynamic simulation can reflect the dangerous working conditions in the project construction process, and make a more complete safety control construction plan for the project construction process.
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Liu, Kaifu, Yiguo Yang, Lei Wang, Jiapei Xu, and Xinyu Xie. "Experimental Investigation of Geosynthetic-Reinforced Pile-Supported Composite Foundations under Cyclic Loading." Advances in Civil Engineering 2020 (December 17, 2020): 1–11. http://dx.doi.org/10.1155/2020/8886131.
Full textAbstract:
A series of model tests were conducted in this study to investigate the deformation characteristics of geosynthetic-reinforced pile-supported (GRPS) composite foundations under cyclic loading. The effects of the applied load, the number of geogrid layers, and types of piles on the performance of the GRPS composite foundation were studied through 1g physical models of composite foundation with well-planned instrumentation. Furthermore, a numerical fitting method was used to assess the relationship between the foundation settlement and the number of load cycles. The results show that with the increase in the magnitude of cyclic load and the number of load cycles, the settlement of GRPS composite foundations and the strain of the pile and geogrid increased accordingly. Adding rigid piles and increasing the number of geogrid layers both could reduce the settlement of GRPS composite foundations, while adding rigid piles was more effective. The relationship between the foundation settlement and the number of load cycles can be expressed by an exponential regression function. The pile strain varied from place to place that the strain of the upper part of the pile was greater than that of the lower part. The geogrid showed a significant impact on the load transfer mechanism of the composite foundation as the geogrid closer to piles endured larger strain. It is critical to consider the variation of the pile strain and the geogrid strain under cyclic loading in the geotechnical practice of composite foundation. The model test results also suggest that the use of GRPS system can effectively reduce the composite foundation settlement. This paper can provide useful references for developing the theoretical framework and design guides for GRPS composite foundations under cyclic loading.
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Kolesnikov, Aleksei O., Tatiana N. Kostiuk, and Vladimir N. Popov. "Calculation of foundation vertical stiffness with the piles mutual influence effect." Structural Mechanics of Engineering Constructions and Buildings 15, no. 3 (December 15, 2019): 229–36. http://dx.doi.org/10.22363/1815-5235-2019-15-3-229-236.
Full textAbstract:
Aims of research. Studies to determine the effect of the distance between the piles in group with vertical oscillations of pile foundations on the value of dynamic stiffness are carried out and the results obtained in full-scale tests, within the wave model and according to SP 26.13330.2012 are compared. Methods. The eigenfrequency changes of the foundation of nine piles with a diameter ( d ) with a high pile cap are calculated depending on the distances between the piles - 2 d , 3 d and 5 d . The obtained results are compared with the data obtained after a series of pulse dynamic loads performed under semi-natural conditions on foundation models. The values of the transverse wave velocities were determined directly at the test site. Results. It is found that the reduction of the distance between the piles in the bush leads to a decrease in the natural vibration frequencies of pile foundations. Reducing the distance between piles from 5 to 2 diameters of piles leads to reduce the frequency of vertical vibrations of pile foundations by 1. times. It is shown the advantage of the results of calculations in the frame-work of the wave model in comparison with the method of SP 26.13330.2012. Also shown their high coincidence with the values obtained in the course of experiments, which allows to accurately determine the amplitude-frequency characteristics of the foundations. The results determined according to SP 26.13330.2012 have significantly lower values of natural frequencies and do not fully reflect the change in the distance between the piles. The maximum discrepancy with the experimental data is 2.7 times for the vertical oscillations of the pile foundation.
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Sailauova, Dilnura, Zhamilya Mamesh, Dichuan Zhang, Deuckhang Lee, Chang-Seon Shon, and Jong R. Kim. "Group Pile Effect on Temperature Distributions inside Energy Storage Pile Foundations." Applied Sciences 10, no. 18 (September 21, 2020): 6597. http://dx.doi.org/10.3390/app10186597.
Full textAbstract:
Energy storage pile foundations are being developed for storing renewable energy by utilizing compressed air energy storage technology. Previous studies on isolated piles indicate that compressed air can result in pressure and temperature fluctuations in the pile, which can further affect safety of the pile foundation. Meanwhile, the temperature changes and distributions for the pile and surrounding soil also are influenced by adjacent piles in typical group pile constructions. Therefore, dynamic thermal transfer simulations were conducted in this paper to investigate the temperature changes and distributions in the concrete pile and surrounding soil for group pile construction. The main parameter in this study is the spacing of the piles. The analysis results show that the group pile effect significantly increases the temperature up to more than 100 °C depending on the location and changes its distribution in both concrete and soil due to the heat transferred from the adjacent piles. The final stabilized temperature can be as high as 120 °C in the concrete pile and 110 °C in the soil after numerous loading cycles, which is about 4 times higher than typical thermo-active energy pile applications. Thus, it is important to include the group pile effect for design and analysis of the energy storage pile foundation.
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Utkin, Vladimir S., and Sergey A. Solovyev. "Development of improved models for pile load bearing capacity, settlement and reliability analysis." Vestnik MGSU, no. 6 (June 2020): 789–823. http://dx.doi.org/10.22227/1997-0935.2020.6.789-823.
Full textAbstract:
Introduction. Safety of operation and durability of pile foundations and structures as a whole depend on the values of load bearing capacity of piles and reliability in the foundation soils. The key problem of pile analysis consists in reliable determination of its load bearing capacity values according to all performance criteria of the first and second groups of limit states, in revealing of reliable values of reliability (operation safety), economic efficiency and profitability.
Materials and methods. One of the difficulties in detecting the value of the load bearing capacity of friction piles is to determine the values of friction and cohesive forces and their distribution over the side surface of the pile in the foundation soil when the loaded pile is immobilized (at rest).
Results. Absence of reliable information on actual friction and cohesive force and, consequently, on actual load bearing capacity of a pile in the conditions of immobility does not allow to estimate its quality taking into account assurance of trouble-free operation (reliability) in real operating conditions at the pre-set operating load, it is impossible to predict the durability of a pile, to make a reasonable choice of pile shape and dimensions, etc. Another pile analysis problem is determining the value of pile settlement. The value of pile settlement is in some cases the most important indicator of the facility performance.
Conclusions. New approaches to the operation of piles in the foundation soil on the basis of modern methods of reliability calculations with limited statistical information about controlled parameters are proposed. Improvement and development of pile calculation methods can be found in the calculation of deep trencher foundations, in the calculation of open caissons and caissons, the development of new statutory documents on pile foundations; as well as during training process of various universities and as a source for advanced training of specialists.
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Ma, Tianzhong, Yanpeng Zhu, Xiaohui Yang, and Yongqiang Ling. "Bearing Characteristics of Composite Pile Group Foundations with Long and Short Piles under Lateral Loading in Loess Areas." Mathematical Problems in Engineering 2018 (November 12, 2018): 1–17. http://dx.doi.org/10.1155/2018/8145356.
Full textAbstract:
It is very necessary to research the bearing characteristics of composite pile group foundations with long and short piles under lateral load in loess areas, because these foundations are used widely. But few people researched this problem in loess areas up to now worldwide. In this paper, firstly, an indoor test model of a composite pile foundation with long and short piles is designed and then employed to explore the vertical load bearing characteristics and load transfer mechanisms of a single pile, a four-pile group, and a nine-pile group under different lateral loads. Secondly, ANSYS software is employed to analyze the load-bearing characteristics of the test model, and for comparison with the experimental results. The results demonstrate the following. (1) The lateral force versus pile head displacement curves of the pile foundation exhibit an obvious steep drop in section, which is a typical feature of piercing damage. A horizontal displacement limit of the pile foundation is 10 mm and 6mm for the ones sensitive to horizontal displacement. (2) The axial force along a pile and frictional resistance do not coincide, due to significant variations and discontinuities in the collapsibility of loess; a pile body exhibits multiple neutral points. Therefore, composite pile groups including both long and short piles could potentially maximize the bearing capacity and reduce pile settlement. (3) The distribution of stress and strain along the pile length is mainly concentrated from the pile head to a depth of about 1/3 of the pile length. If the lateral load is too large, short piles undergo rotation about their longitudinal axis and long piles undergo flexural deformation. Therefore, the lateral bearing capacity mainly relies on the strength of the soil at the interface with the pile or the horizontal displacement of the pile head.
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Wu, Chuan-Sheng, Jian-Qiang Zhang, Ling-Ling Qi, and De-Bing Zhuo. "Defect Identification of Concrete Piles Based on Numerical Simulation and Convolutional Neural Network." Buildings 12, no. 5 (May 17, 2022): 664. http://dx.doi.org/10.3390/buildings12050664.
Full textAbstract:
Defects in pile foundations, such as neck defects, bulge imperfections, weak concretes, cracks, and broken piles, can cause a decrease in the bearing capacity and the structural stability of the foundation. Identification of the type of defect is vital in formulating a reasonable repair plan for the pile foundation. In this study, the authors proposed a scheme to identify the types of defects in concrete piles based on a convolution neural network and a low-strain pile integrity test (LSPIT). A batch modeling method of defective pile foundations using Python script was also proffered. The different degrees of signals of five types of defective pile foundations were simulated by this method. The original data were decomposed and reconstructed by wavelet packet decomposition (WPT). To prevent the data from losing too much information after WPT, the data of 400 × 1 after decomposition and reconstruction were processed by dimension-raising to obtain the data of 20 × 20 × 1. Then, the multidimensional feature index of 20 × 20 × 2 was generated by index fusion with the original data. Finally, the data were input onto convolutional neural network (CNN) as a training parameter. Following an improvement of the dataset, the recognition accuracy of the type of defect in the pile foundation by the proposed identification scheme reached 94.4%.
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Kang, Gichun, Seong-Kyu Yun, Tae-Hyung Kim, and Jiseong Kim. "Lateral and Overturning Resistance of Wind Turbine Foundations Reinforced with Piles on Bedrock by Modelling Experiments." Journal of Marine Science and Engineering 9, no. 9 (August 24, 2021): 919. http://dx.doi.org/10.3390/jmse9090919.
Full textAbstract:
This study evaluated the lateral and overturning resistance of wind turbine foundations reinforced with piles on bedrock through model experiments. In particular, changes in lateral and overturning resistance of wind turbine foundations were analyzed according to cross-sectional size and the presence of piles of wind turbine foundations. As a result, by reducing the cross-section, the lateral resistance of the pile-reinforced wind turbine foundation was compared to the existing wind turbine foundation with large cross-sections and was shown to be 1.68 times greater. In the case of vertical displacements affecting overturning, the safety of overturning was also greater, as the vertical displacement of the pile-reinforced wind turbine foundation was 36% smaller than the existing wind turbine foundation. As a result of the unidirectional cyclic load on a pile-reinforced wind turbine foundation, lateral resistance value was similar to that of the static load in target displacement value, and it showed that the elastic resilience was very large due to pile reinforcement. According to the bending moment measurement of piles embedded in wind turbine foundations and bedrock, bending moments were large in the order of the front row, the right-hand row, and the back row, while the maximum bending moment generation was found on the boundary surface of the wind turbine foundation and the rubble mound layer for the front row, as well as on the boundary surface of the rubble mound layer and bedrock for the right-hand row and back row.
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Zhu, Rui, Feng Zhou, Zhihui Wan, Shengjun Deng, Xin Dong, Zekun Zhou, and Wei Xing. "Improving the Performance of Piled Raft Foundations Using Deformation Adjustors: A Case Study." Buildings 12, no. 11 (November 6, 2022): 1903. http://dx.doi.org/10.3390/buildings12111903.
Full textAbstract:
Complicated soil conditions are direct difficulties for high-rise building projects. A new device called a deformation adjustor, which is used to optimize the stiffness distribution in the piled raft system, has achieved good results for this challenge. This paper presents a case study on the application of deformation adjustors to improve the performance of a piled raft foundation. This case study describes the preliminary design of pile-raft foundations with deformation adjustors, followed by numerical analysis. Based on the numerical study, the potential savings are demonstrated due to the good performance of soil bearing capacity. Comparing the numerical results with the monitoring results in raft settlements, earth pressures, deformation amount of deformation adjustors, pile top reactions, and load-sharing ratios between soils and piles, the accuracy of the design schemes with an aided numerical analysis is verified. Through a long-term monitoring, soils below the raft carried 63% of the total applied loads, while the piles bear 37% of the loads. This case study proved that a piled raft foundation with deformation adjustors was an effective and economical design scheme, which can make full use of the soil bearing capacity. It is of great significance to facilitate the design and construction of piled raft foundations in complicated soil conditions.
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Vu, Anhtuan, Ducphong Pham, Tuonglai Nguyen, and Yu He. "3D Finite Element Analysis on Behaviour of Piled Raft Foundations." Applied Mechanics and Materials 580-583 (July 2014): 3–8. http://dx.doi.org/10.4028/www.scientific.net/amm.580-583.3.
Full textAbstract:
This paper highlights settlement behaviour of piled raft foundation by 3D finite element analysis through Plaxis 3D Foundation program. The effects of pile number, pile length, pile layout and pile spacing on the behaviour of piled raft foundation were studied. The numerical results show that: Piled raft foundation has much more efficency to reduce settlement than that of traditional raft foundation. The value of vertical defomation decreases as the result of the increase of pile number, pile length, pile spacing and vice versa. Pile layout has significant effect on both value and location of maximum settlement of piled raft foundation.
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Ye, Chao Liang, Huai Ping Feng, and Yao Jun Liu. "In Situ Study on Reinforced Effect of Silt by Ram-Compaction Gravel Pile with End Expansion." Advanced Materials Research 446-449 (January 2012): 3428–31. http://dx.doi.org/10.4028/www.scientific.net/amr.446-449.3428.
Full textAbstract:
Ram-compaction gravel pile with end expansion is widely adopted in the treatment of silty clay foundations. In this paper, the bearing properties of rammed gravel pile reinforced foundations and soil between piles were investigated by use of static load tests and heavy-duty dynamic penetration test. It is demonstrated that the settlement curves (P-S curve) of ram-compaction gravel pile with end expansion reinforced foundation and soil between piles were monotonic, without turning point being observed. With the increases of pile length, the bearing capacity of pile increases. According to the experimental results from heavy dynamic penetration tests and static load test, the strength of soil between piles is improved, which also have effects on the elimination of the uneven settlements. Comparison the results between heavy-duty dynamic penetration tests and over-heavy dynamic penetration tests shows that the later one is suitable on testing of the soil properties between piles. In addition, from in-situ measurements of uplift deformation of different depths, it is found that uplift behavior occurs with depth more than 0.5m, whit largest uplift value of 21cm. The result provides a reference for the design and construction of rammed gravel pile reinforced foundation.
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Zhu, Xiao-jun, Kang Fei, and Sheng-wei Wang. "Horizontal Loading Tests on Disconnected Piled Rafts and a Simplified Method to Evaluate the Horizontal Bearing Capacity." Advances in Civil Engineering 2018 (September 16, 2018): 1–12. http://dx.doi.org/10.1155/2018/3956509.
Full textAbstract:
Disconnected piled raft (DPR) foundations have been widely adopted as an effective foundation system where the piles are separated from the raft by a granular layer, which can limit the shear forces and moments transmitted between the raft and the piles. Thus, DPR foundations may avoid the problem of horizontal forces, such as those from an earthquake or dynamic loads, which damage the structural connection between the pile head and raft. A series of static horizontal loading tests were carried out on three types of foundation models, i.e., piled raft, disconnected piled raft, and raft alone models, on fine sand using a geotechnical model in a 1 g field. In this paper, the influences of vertical loading and interposed layer thickness were presented and discussed. The results showed that most of the horizontal force was carried by raft/interposed layer friction in the DPR foundation type, and the shear force and moment of the piles were greatly reduced due to the gap between the raft and the heads of the piles. The tested foundations were simulated using a simplified method with theoretical equations derived by making several approximations and assumptions. The simulated results agreed well with the test results.
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Huang, Ting, Yinghui Tian, Guoliang Dai, and Ao Jiao. "Experimental Study of Wave-Induced Response of Piles in Seabed with Various Permeability." Applied Sciences 12, no. 5 (March 4, 2022): 2698. http://dx.doi.org/10.3390/app12052698.
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Subjected to continuous wave loading, the responses of pile foundations and seabed develop gradually, severely affecting the serviceability of piled structures. This paper presents the results of a series of flume experiments on pile foundations in fine sandy and silty seabed under regular wave loading. Pile-head displacement and pore water pressure were measured and the effects of pile diameter, cross-section, pile stiffness and wave height were investigated. The experimental results indicate that the pore pressure in fine sandy seabed varied only slightly even under 640 s of wave loading but showed an increase of 15.7–25.9% around a pile. In silty seabed with much lower permeability, pore pressure accumulated quickly due to piles and oscillated impressively at the depth of soil liquefaction. Based on the comparison between the calculated and measured pile-head displacement, we found that the response of smaller-diameter piles in lower-permeability seabed was much more easily magnified by the induced pore pressure. Increasing the pile diameter and attaching fins could lead to a smaller response of piles. Wave height was a major factor in the experiments that affected the development of response.
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Mangnejo, Dildar Ali, and Naeem Mangi. "The Responses of an End-Bearing Pile to Adjacent Multipropped Excavation: 3D Numerical Modelling." Civil Engineering Journal 5, no. 3 (March 18, 2019): 552. http://dx.doi.org/10.28991/cej-2019-03091267.
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It is well recognised that superstructure load is transferred to surrounding soil through piled foundation. Consequently, the high stress regime (stress bulb) is generated surrounding of the pile. On the other hand, the excavation in the ground inevitably results in the ground movement due to induced-stress release. These excavations are sometimes inevitable to be constructed adjacent to existing piled foundations. This condition leads to a big challenge for engineers to assess and protect the integrity of piled foundation. This research presents three-dimensional coupled consolidation analyses (using clay hypoplastic constitutive model which takes account of small-strain stiffness) to investigate the responses of an end-bearing pile due to adjacent excavation at different depths in soft clay. The effects of excavation depths (i.e., formation level) relative to pile were investigated by simulating the excavation near the pile shaft (i.e., case S) and next to (case T). It was revealed that the maximum induced bending moment in the pile after completion of excavation in all the cases is much less than the pile bending moment capacity (i.e. 800 kNm). Comparing the induced deflection of the end-bearing pile in the case T, the pile deflection in case S is higher. Moreover the piles in cases of S and T were subjected to significant dragload due to negative skin friction.
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Janda, Tomás, Renato P. Cunha, Pavel Kuklík, and Gérson M. Anjos. "Three Dimensional Finite Element Analysis and Back-analysis of CFA Standard Pile Groups and Piled Rafts Founded on Tropical Soil." Soils and Rocks 32, no. 1 (January 1, 2009): 3–18. http://dx.doi.org/10.28927/sr.321003.
Full textAbstract:
This paper deals with Plaxis 3D finite element simulations of the mechanical response of deep foundations founded in a collapsible tropical soil. Main attention is initially paid to differences between single continuous flight auger (CFA) pile behavior and the behavior of CFA piles in standard groups. The numerically computed load-settlement curves are compared to field load test data obtained at the experimental research site of the University of Brasília (UnB), leading to conclusions about the appropriateness of adopting laboratory, in situ or back calculated parameters as input of numerical programs that simulate 3D foundation systems. Further, the contribution of the contact surficial soil/top raft is numerically examined by simulating the behavior of identical “piled raft” systems founded in the same site. The numerical simulated results of “piled raft” and standard pile group systems are then compared in terms of load capacity, system stiffness, load share between pile tip, shaft and raft, and mean developed lateral pile shaft friction. Having the results at distinct loading stages, as at working and failure levels, the analyses show the differential behavior, and design obtained responses, one may expect from conventional pile groups and “piled rafts” of CFA floating piles when founded in tropical soils. It is a mixed theoretical/experimental paper with practical interest for foundation designers and constructors.