Journal articles: 'Soil Nails'

1

Sharma, M., M. Samanta, and S. Sarkar. "Laboratory study on pullout capacity of helical soil nail in cohesionless soil." Canadian Geotechnical Journal 54, no. 10 (October 2017): 1482–95. http://dx.doi.org/10.1139/cgj-2016-0243.

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Helical nails are a new alternative to conventional soil nails or tie-backs for stabilization of slopes, excavations, and embankments due to ease of installation, minimal site disturbance, and immediate loading capability. Pullout capacity of helical nails is a critical parameter for their design. This study investigates the pullout behaviour of helical soil nails installed in dry dense sand through a series of laboratory tests. The tests were performed on seven different types of helical nails in a displacement-controlled manner. The paper describes the test procedure, results and highlights the influence of different parameters on the pullout capacity. Results show that roughness of the nail shaft significantly influences the peak pullout capacity of helical soil nails. A linear relationship between peak pullout force and overburden pressure is observed for different types of helical soil nails, indicating that it satisfies the Mohr–Coulomb failure criteria. A helical soil nail having a double helix of unequal diameter and the same interspacing shows higher pullout capacity than a helical soil nail having a double helix of the same diameter. The position of the helix and spacing-to-diameter ratio of the soil nail with a double helix of unequal diameter plays a significant role on the peak pullout capacity.

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Liu, Zhong Yu, Chong Wu Ma, and Zhuo Zhao. "Laboratory Experimental Study on Pullout Behavior of Mortar Grouted GFRP Soil Nails." Advanced Materials Research 168-170 (December 2010): 1069–72. http://dx.doi.org/10.4028/www.scientific.net/amr.168-170.1069.

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A large-scale laboratory apparatus has been built to study the pullout behavior of mortar grouted glass fiber reinforced polymer (GFRP) soil nails. The axial strain along the nail length and the displacement of the nail head under different pullout loads are measured, and the ultimate pullout load under the overburden pressure is obtained. Then, the influence of the overburden pressure on the ultimate value of the interface friction force is investigated. The experimental results illustrate that the pullout behavior of mortar grouted GFRP soil nails is similar to that of mortar grouted steel soil nails, and the relation between the displacement and the pullout load can be described with the hyperbolic function. In addition, the dilatancy effect of the soil near the nail during pull out should be taken into account in estimating the pullout resistance of soil nails in dense fills.

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Cheuk, C. Y., K. K. S. Ho, and A. Y. T. Lam. "Influence of soil nail orientations on stabilizing mechanisms of loose fill slopes." Canadian Geotechnical Journal 50, no. 12 (December 2013): 1236–49. http://dx.doi.org/10.1139/cgj-2012-0144.

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Soil nailing has been used to upgrade substandard loose fill slopes in Hong Kong. Due to the possibility of static liquefaction failure, a typical design arrangement comprises a structural slope facing anchored by a grid of soil nails bonded into the in situ ground. Numerical analyses have been conducted to examine the influence of soil nail orientations on the behaviour of the ground nail–facing system. The results suggest that the use of steeply inclined nails throughout the entire slope could avoid global instability, but could lead to significant slope movement especially when sliding failure prevails, for instance, due to interface liquefaction. The numerical analyses also demonstrate that if only subhorizontal nails are used, the earth pressure exerted on the slope facing may cause uplift failure of the slope cover. To overcome the shortcomings of using soil nails at a single orientation, a hybrid nail arrangement comprising nails at two different orientations is proposed. The numerical analyses illustrate that the hybrid nail arrangement would limit slope movement and enhance the robustness of the system.

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Wu, Jason Y., and Jr Min Chang. "Effect of Wetting on the Pullout Resistance of Grouted Soil Nails." Applied Mechanics and Materials 226-228 (November 2012): 1304–7. http://dx.doi.org/10.4028/www.scientific.net/amm.226-228.1304.

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In this research, laboratory pullout tests were conducted on grouted soil nails to study the effect of wetting on the interface shear resistance between nail and soil during pullout. Deformed bars with equal size to the true soil nails were used as model nails. The soil used was silty fine sand collected at the site and prepared to a very dense condition. Rainfall infiltration was simulated using duplicated soil nails inundated by water for different periods. Test results indicated that the peak pullout resistance strongly decreases upon wetting, with a reduction of about 60% after soaking for 28 days. However, the experiments showed that there is a threshold water content (or soaking time) beyond which the effect of infiltration on the pullout resistance is reduced. The laboratory protocols developed in this study offered an easy scheme for the prediction of the pullout capacity of a grouted soil nail upon wetting.

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Vojtasik, Karel, Milan Chodacki, and Tomas Hochsmann. "Ground Improvement by a Nonparallel Layout of Soil Nails." Advanced Materials Research 1020 (October 2014): 447–50. http://dx.doi.org/10.4028/www.scientific.net/amr.1020.447.

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Soil nails are components retaining a ground to give it support particular in cases when the ground doesn’t satisfy fully the requirements and it is expected an excessive deformation or the worst a collapse. Today in all geotechnical applications the soil nails are arranged in the simplest way i.e. they are all parallel and almost perpendicular the boundary face of the ground body to be bound. Submitted article is a feasibility study on application the soil nails in another a nonparallel scheme of nails arrangement. The nails are located in two closely adjacent parallel plains. The nails are inclined in each plain with regard to a boundary face of the ground body and the nail inclination heads in opposite direction in each plain. This way the nails build up a quasi-web scheme in the ground. Article analyzes the effect of the quasi-web scheme nails arrangement on the ground and looks for an exact solution to evaluate effect on ground strength and strain behavior. The force balance approach is employed for the exact analysis.

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Yu, Jung-Doung, Ki-Hong Kim, and Jong-Sub Lee. "Nondestructive health monitoring of soil nails using electromagnetic waves." Canadian Geotechnical Journal 55, no. 1 (January 2018): 79–89. http://dx.doi.org/10.1139/cgj-2017-0043.

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The installed length and grouted length of a soil nail should be evaluated to prevent construction disasters and landslides. The objective of this study is the development and application of a nondestructive method for evaluating the installed length and grouted length of soil nails using electromagnetic waves. Experiments are conducted on steel bars, partially grouted steel bars, fully grouted steel bars, and soil nails. Electromagnetic waves are generated and detected by a time-domain reflectometer. The experimental results show that the respective round-trip travel times increase with an increase in the length of the steel bar, grouted steel bar, and soil nail. The velocities are greatest and lowest for steel bars and soil nails installed in soil, respectively. For partially grouted steel bars, multiple reflections are detected at the interface between the nongrouted sections and grouted sections. The velocity decreases with an increase in the grouted ratio of the soil nail. This study demonstrates that electromagnetic waves can be effectively applied for the evaluation of the installed length and grouted length of the soil nail for health monitoring.

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7

Mohamed, Mahmoud H., Mohd Ahmed, Javed Mallick, and Pham V. Hoa. "An Experimental Study of a Nailed Soil Slope: Effects of Surcharge Loading and Nails Characteristics." Applied Sciences 11, no. 11 (May 25, 2021): 4842. http://dx.doi.org/10.3390/app11114842.

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The earth nailing system is a ground improvement technique used to stabilize earth slopes. The behavior of the earth nailing system is dependent on soil and nailing characteristics, such as the spacing between nails, the orientation, length, and method of installation of nails, soil properties, slope height and angle, and surcharge loading, among others. In the present study, a three-dimensional physical model was built to simulate a soil nailed slope with a model scale of 1:10 with various soil nail characteristics. The simulated models consist of Perspex strips as facing and steel bars as a reinforcing system to stabilize the soil slope. Sand beds in the model were formed, using a sand raining system. The performance of nailed soil slope models under three important nails characteristics, i.e., length, spacing and orientation, with varying surcharge loading were studied. It was observed that there is a reduction in the lateral movement of slope and footing settlements with an increase in length. It was found that the slope face horizontal pressure is non-linear with different nail characteristics. The increase in length and inclination of the soil nails decreased the vertical, horizontal stress and footing settlement, while the increase in spacing of the nails increased the vertical and horizontal stress behind the soil mass.

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Mohamed, Mahmoud H., Mohd Ahmed, and Javed Mallick. "Pullout Behavior of Nail Reinforcement in Nailed Soil Slope." Applied Sciences 11, no. 14 (July 12, 2021): 6419. http://dx.doi.org/10.3390/app11146419.

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The pullout resistance and displacement performance of reinforcement have significant effects on the safe and economic design of a reinforced-soil system. In this study, the nail pullout tests are conducted to assess the pullout behavior of soil nail reinforcement at different levels in the soil slope of granular materials. The similitude laboratory models of a reinforced soil system with a scale of 1:10 are prepared. The construction sequence used in a full scale slope was precisely followed in the laboratory model. The models consist of a Perspex wall box filled with sand and steel bars as a reinforcement. The models of sand beds are formed using an automatic sand raining system. Devices and instruments are installed to record the nails pullout resistance and displacement. The tests are carried out at variable footing pressures to get the pullout force of the nails based on a strain control technique. The finite element models of nailed soil slope are also analyzed to validate the laboratory model results. It infers from the numerical model results that the laboratory models underestimate the pullout behavior of nail reinforcement in nailed soil slope. The pull-out force in nail reinforcement increases as the displacement increases and then decreases slightly and becomes constant with an increase in displacement in the case of deeper placed nails, but it becomes constant immediately for upper nails.

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9

Pham, Nhan Thi, Pan Bing, and Nghia Viet Nguyen. "Study on the effect of some parameters of soil nails on the stability of vertical slopes." Journal of Mining and Earth Sciences 61, no. 6 (December 31, 2020): 30–37. http://dx.doi.org/10.46326/jmes.2020.61(6).04.

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Soil nailing is one of the soil reinforcement techniques that has been used worldwide in geotechnical engineering. In Viet Nam, soil nailing technology applied in a number of transportation investments such as Ha Long - Van Don, Bac Giang - Lang Son highways, and some of the hydropower plants in the central provinces of Viet Nam. Soil nailing is a system consisting of reinforced concrete piles and rebars or composite rods installed in an inclined direction into the slope. The research and applications of soil nailing technology to reinforceslopes in Viet Nam have not been widespread. The authors only considered construction technologies, processes, requirements for the materials, equipment, quality - check of soil nails, etc. The optimal geometries of soil nails for the stability of slope are inadequate and analyzed thoroughly. These lead to inaccurate prediction of the construction stabilization effect and the safety of designed structures. In the present study, numerical simulations were conducted to investigate the effects of the inclined angle and the length of soil nail Patterns and subjected to surcharge loads on stability improvement of soil - nailed slopes and facing deformation in a staged - excavation. The research results show that the soil nail reinforcement efficiency could be affected by inclinations and length Pattern s of soil nails. The general conclusion is that the more soil is nailing inclinations, the more the reinforcing forces in the soil nails. The soil nail length Patterns have also influenced displacement characteristics of slopes.

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Benamara, Fatima Zohra, and Lazhar Belabed. "Stability of the Walls in Nails Soil." Advanced Materials Research 324 (August 2011): 380–83. http://dx.doi.org/10.4028/www.scientific.net/amr.324.380.

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Developed as from the seventies, the nailing of the soils is a technique, which makes it possible to carry out a retaining wall of excavation by using the soil in place and installing the passive bars called nails. The main object of this work is to study the stability of the walls in soil nailed lived overall rupture facing-soil-nail. In order to find the mechanism or the mechanical model most unstable. Give a general aspect to our studies; we also studied a title comparative the classical circular failure model. We have repeatedly determined for each case the maximum shear soil force in the nails Tm. The most unfavourable mechanism (less stable) among all the mechanisms is that for which, the shear force Tm reached a maximum. Another analysis of the stability of wall in nailed soil was made by means of the software Geo4 and compared with the kinematics method.

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11

Su, Li Jun, Jian Hua Yin, and Hong Jian Liao. "Influence of Soil Dilatancy on Soil Nail Pull-Out Resistance in Completely Decomposed Granite Fill." Key Engineering Materials 340-341 (June 2007): 1237–42. http://dx.doi.org/10.4028/www.scientific.net/kem.340-341.1237.

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Soil nailing, developed from the New Austrian Tunnelling Method, has been widely used in many countries and regions in the world since the 1970’s. This technique is used to stabilize in situ soil mass by installing a large number of closely spaced unstressed inclusions into the soil mass to increase its strength and stability. Since the mid 1970’s, several design methods have been proposed based on laboratory and field tests. Among the design criteria in these methods, the pull-out resistance of a soil nail is a key parameter that controls the stability assessment of soil nail structure. In the previous investigations, the soil dilatancy was found to be an important factor that influences the soil nail pull-out resistance especially for drill-and-grout soil nails. In order to study the influence of soil dilatancy on soil nail pull-out resistance, laboratory pull-out tests and numerical parametric studies have been carried out for soil nails in Completely Decomposed Granite (CDG) fill. The results show that the soil dilatancy has a significant influence on the soil nail pull-out resistance.

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12

Liao, Shu-Tao, Chin-Kuo Huang, and Chung-Yue Wang. "Sonic echo and impulse response tests for length evaluation of soil nails in various bonding mediums." Canadian Geotechnical Journal 45, no. 7 (July 2008): 1025–35. http://dx.doi.org/10.1139/t08-034.

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The objective of this paper is to present the results of research for evaluating the installed lengths of soil nails with nondestructive testing methods. Two closely related methods, the sonic echo test and the impulse response test, both of which had been widely applied to assess the integrity of drilled shafts and driven piles, were evaluated to test their capabilities on soil nails. To carry out this study, soil nails of various lengths were embedded in different surrounding materials in the laboratory and then tested with both methods to predict their lengths. The surrounding materials studied in this research included soil and cement grout. Finally, field tests for in situ soil nails were carried out. The results indicated that the relative stiffness of the soil nail to the bond material plays a very important role in the success of testing. It is hoped that through this kind of study, the capability and limitation of using these nondestructive testing techniques to determine the installed lengths or to evaluate the bonding conditions of soil nails can be better understood.

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13

Hong, Cheng-Yu, Jian-Hua Yin, Hua-Fu Pei, and Wan-Huan Zhou. "Experimental study on the pullout resistance of pressure-grouted soil nails in the field." Canadian Geotechnical Journal 50, no. 7 (July 2013): 693–704. http://dx.doi.org/10.1139/cgj-2012-0103.

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The pullout behaviour of cement-grouted soil nails, particularly in field conditions, is not yet fully understood. In this study, a series of tests was conducted to evaluate the pullout response of grouted soil nails in a field slope. A new innovative grouting packer system was developed to control the grouted length and maintain the cement grout pressure of the grouted part. By using the grouting packer system, a total of 10 soil nails placed at different soil depths were grouted with different pressures in the field. The pullout results of present field tests and a number of past laboratory tests indicate that the apparent coefficient of friction (ACF) decreases with the increase of overburden stress even though grouting pressure is applied. In addition, when the overburden stress is unchanged, the obtained ACF values in the field tests appear to increase almost linearly with the increase of grouting pressure. After the soil nails were completely pulled out of the ground, the surfaces of the soil nails and surrounding soil were examined. It is found that the water content of the soil samples at the soil–nail interfaces decrease substantially compared to the water content of soil samples in drill holes. Measurement results also show that the failure surfaces of soil nails shifted about 16 mm on average into the surrounding soil due to the application of grouting pressure.

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14

Zhou, Yuan-de, Kai Xu, Xinwei Tang, and Leslie George Tham. "Three-Dimensional Modeling of Spatial Reinforcement of Soil Nails in a Field Slope under Surcharge Loads." Journal of Applied Mathematics 2013 (2013): 1–12. http://dx.doi.org/10.1155/2013/926097.

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Soil nailing has been one of the most popular techniques for improving the stability of slopes, in which rows of nails and a structural grillage system connecting nail heads are commonly applied. In order to examine the spatial-reinforcement effect of soil nails in slopes, a three-dimensional (3D) numerical model has been developed and used to back-analyze a field test slope under surcharge loading. Incremental elastoplastic analyses have been performed to study the internal deformation within the slope and the development of nail forces during the application of top surcharge loads. Different treatments of the grillage constraints at nail heads have been studied. It is shown that the numerical predictions compare favorably with the field test measurements. Both the numerical and the field test results suggest that soil nails are capable of increasing the overall stability of a loose fill slope for the loading conditions considered in this study. The axial force mobilization in the two rows of soil nails presents a strong dependence on the relative distance with the central section. With the surcharge loads increased near the bearing capacity of the slope, a grillage system connecting all the nail heads can affect the stabilizing mechanism to a notable extent.

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15

Zamiran, Siavash, Hadi Ghojavand, and Hamidreza Saba. "Numerical Analysis of Soil Nail Walls under Seismic Condition in 3D Form Excavations." Applied Mechanics and Materials 204-208 (October 2012): 2671–76. http://dx.doi.org/10.4028/www.scientific.net/amm.204-208.2671.

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Typically, temporary soil nailing systems are not required to provide for design level earthquake occurrences consistent with the building or structure being constructed inside the excavation. However, the seismic response of the permanent soil nail walls during the earthquakes should be evaluated. On the other hand, evaluation of 3D response of soil nailing walls have some strange manners that should be considered in the numerical analysis. In this paper, numerical simulations of soil nail walls under vibrational input have been carried out, and the results are compared with the function of soil nail walls under ordinary statistical loading. The behaviour of geometry of nails are mentioned under static and seismic analysis. After that some investigations are carried out to find respond of soil nailing walls in some 3D excavation forms. The analysis is performed with finite difference software called FLAC3D. The results are prepared as lateral displacement of the walls and normalized maximum tensile forces for nails. These results can demonstrate the behavior of external and internal resistance of soil nail walls under seismic and static analysis. The deformation of wall under the static and dynamic manner varies in a wide range. On the other hand, tensile loads that are produced in nails under the static manner are namely 50% less than the dynamic manner.

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Menkiti, Christopher O., and Michael Long. "Performance of soil nails in Dublin glacial till." Canadian Geotechnical Journal 45, no. 12 (December 2008): 1685–98. http://dx.doi.org/10.1139/t08-084.

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Soil nailing is being used in many projects in glacial tills in Ireland, particularly to provide temporary support to steep slopes. Little design guidance is available for such materials, and it is known that the application of design procedures developed for other material is conservative. Detailed nail instrumentation and field monitoring has been undertaken during large-scale soil nailing works for the Dublin Port Tunnel project. It was found that the short-term behaviour of nails was the reverse of that assumed in current design methods. Most of the load was induced as a results of drilling and nailing the lift immediately below the nail being monitored rather than due to excavation-induced stress relief. The highest forces were developed in the upper nails where the largest ground movements occurred. This is the reverse of most current design methods where the highest soil–nail bond is assigned to the deepest nails. It seems that the observed short-term, prefailure behaviour of nailed slopes is governed more by the deformation pattern of the slope than by large-scale development of failed wedges. Current design procedures should be reviewed. Despite this, the trial confirmed that the currently used procedures are highly conservative for Dublin glacial till.

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Su, Li-Jun, Terence C. F. Chan, Y. K. Shiu, Tony Cheung, and Jian-Hua Yin. "Influence of degree of saturation on soil nail pull-out resistance in compacted completely decomposed granite fill." Canadian Geotechnical Journal 44, no. 11 (November 2007): 1314–28. http://dx.doi.org/10.1139/t07-056.

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The nail–soil interface shear strength is a key parameter in the design and stability assessment of soil nailing systems. A number of factors will influence the nail–soil interface shear strength. Among these factors, the degree of saturation (Sr) of the soil is an important one especially for permanent soil nail structures. To study the influence of Sr on soil nail pull-out shear resistance, a series of laboratory pull-out tests have been conducted on soil nails in compacted completely decomposed granite (CDG) fill prepared to different Sr. The tests were conducted using two specially designed pull-out boxes (with same specifications). In the near-saturated tests, a high Sr (about 98%) was achieved using two special features of the apparatus: a waterproof front cap and back-water pressure pipes at the bottom of the pull-out box. Test results showed that the nail–soil shearing plane migrated outwards into the soil when the Sr of the soil increased. Also, peak pull-out strengths of soil nails were strongly influenced by the Sr of the soil. Among the tested Sr, the highest values of peak pull-out shear strength were obtained at Sr values between 50% and 75%.

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Hong, Yung-Shan, Cho-Sen Wu, and Shang-Heng Yang. "Pullout resistance of single and double nails in a model sandbox." Canadian Geotechnical Journal 40, no. 5 (October 1, 2003): 1039–47. http://dx.doi.org/10.1139/t03-048.

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Pullout tests on single and double soil nails were conducted in a model sandbox. The test parameters included variations in the surface roughness, the ratio of nail length to nail diameter, the overburden pressure, and the distance between two nails. The characteristic of a single asperity, the asperity number per unit length, and the ratio of the thread depth to the soil particle size were used to define the surface roughness factor. The test results showed that the apparent friction coefficients at the soilnail interface were dependent upon the surface roughness of the nail. Group efficiency was used to evaluate the effectiveness of a nail when installed within a group. The test results showed that the group efficiency of a double-nail system was dependent upon the surface roughness factor and has a linear relationship with the nail distance until 100% efficiency is reached. The minimum required distance for 100% efficiency also varied with the surface roughness factor.Key words: apparent friction coefficient, group efficiency, pullout test, surface roughness factor.

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19

Tokhi, H., G. Ren, and J. Li. "Laboratory pullout resistance of a new screw soil nail in residual soil." Canadian Geotechnical Journal 55, no. 5 (May 2018): 609–19. http://dx.doi.org/10.1139/cgj-2017-0048.

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The ultimate shear strength at the interface between the soil nail and surrounding soil is of practical importance in the design and performance of a soil nail system. The most commonly adopted method of measuring this interface shear strength is by soil nail pullout testing. This study introduces a novel soil nail system in the form of a screw nail and compares its performance with a conventional grouted soil nail. Both types of soil nails are tested in a controlled laboratory setting using residual soil in a large purpose-made pullout box. The development of the screw nail and the laboratory testing procedures are briefly discussed first, followed by presentation and discussion of the results of the interface shear behaviour measured from pullout tests. It is shown that the screw nail offers many advantages in terms of pullout load–displacement behaviour and the interface shear mechanism than that of the conventional grouted soil nail.

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Cheng, Y. M., S. K. Au, and Albert T. Yeung. "Laboratory and field evaluation of several types of soil nails for different geological conditions." Canadian Geotechnical Journal 53, no. 4 (April 2016): 634–45. http://dx.doi.org/10.1139/cgj-2015-0267.

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For steep slopes with difficult access or slopes in a corrosive environment, there are various problems associated with the use of conventional steel reinforcement bars as soil nails. For loose-fill slopes or clay slopes, the development of adequate nail bond strength is another practical issue that should be considered. Carbon fiber–reinforced polymer (CFRP) and glass fiber–reinforced polymer (GFRP) in several forms and installation methods have been studied as the alternatives to the classical steel bar. Extensive laboratory tests on the materials and field tests on different types of soil nails with various methods of installation have been carried out in Hong Kong, Korea, and Australia. Test results support the use of these materials with an innovative installation method as soil nails under different geological conditions, and the suitability and performance of these materials under different conditions are assessed in the present study.

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Hirschmüller, Sebastian, Roman Marte, and Alexander Englberger. "Applicability of finger jointing to circular laminated veneer hollow sections for temporary soil nailing." European Journal of Wood and Wood Products 78, no. 5 (August 6, 2020): 879–89. http://dx.doi.org/10.1007/s00107-020-01577-y.

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Abstract This paper investigates the strength properties of circular laminated veneer lumber hollow sections made of beech wood and loaded in tension. These tubular, hollow wooden poles are intended for an innovative geotechnical approach, which utilizes the high tensile strength of beech wood and its limited durability as soil nails for temporary geotechnical slope stabilisation. Due to the standardized design approaches of soil nail walls that prevent a rigid soil body from sliding by using nails as reinforcement elements, primary tension loads will be aligned to the structural elements. Depending on the height of the soil nail wall, nails with a length up to 10 m may be necessary, demanding for high-performance longitudinal section joints due to the natural length limitations of the wood veneer. This paper discusses the applicability of finger jointing to tubular, laminated beech wood veneer poles and presents the results of large-scale tensile tests. Depending on the joint arrangement, the median tensile strength is reduced by 37–43% compared to the unjointed sections of a similar geometry. Thus, finger jointing has been found to be an efficient method of a longitudinal load-carrying connection in combination with a minimized cross section reduction at the joint. However, due to the low sample size of the tests, further improvements are necessary.

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Li, Feng, Yuan Cheng Guo, Gang Shi, and Hui Qian. "The Time History of Axial Force of Soil Nail in Deep Excavation Course." Advanced Materials Research 243-249 (May 2011): 2259–65. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.2259.

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This paper presents a theoretically study on the time-dependent characteristic of soil-nail axial force in the whole construction process of foundation pit. Firstly, the time-varying performance of axial forces of soil nails is analyzed according to the measured lateral deformation curves of pile-anchor and soil-nail composite supporting deep foundation pit. Then combined with a soil rheological model, a time-dependent formula of soil nail axial force is put forward, and the simulated results are compared to the back-analyzed ones. Finally, a formula to predict the time-dependent axial force of soil nail in the whole construction process of foundation pit is established and an example is investigated to validate the method.

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Liu, Huifen, Liansheng Tang, and Peiyuan Lin. "Maximum Likelihood Estimation of Model Uncertainty in Predicting Soil Nail Loads Using Default and Modified FHWA Simplified Methods." Mathematical Problems in Engineering 2017 (2017): 1–14. http://dx.doi.org/10.1155/2017/7901918.

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Accuracy evaluation of the default Federal Highway Administration (FHWA) simplified equation for prediction of maximum soil nail loads under working conditions is presented in this study using the maximum likelihood method and a large amount of measured lower and upper bound nail load data reported in the literature. Accuracy was quantitatively expressed as model bias where model bias is defined as the ratio of measured to predicted nail load. The maximum likelihood estimation was carried out assuming normal and lognormal distributions of bias. Analysis outcomes showed that, based on the collected data, the default FHWA simplified nail load equation is satisfactorily accurate on average and the spread in prediction accuracy expressed as the coefficient of variation of bias is about 30%, regardless of the distribution type. Empirical calibrations were proposed to the default FHWA simplified nail load equation for accuracy improvement. The Bayesian Information Criterion was adopted to perform a comparison of suitability between the competing normal and lognormal statistical models that were intended for description of model bias. Example of reliability-based design of soil nail walls against internal pullout limit state of nails is provided in the end to demonstrate the benefit of performing model calibration and using calibrated model for design of soil nails.

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Huang, Jian Hua, Guang Song, and Er Xaing Song. "Optimization Simulations of Support System by Composite Soil-Nail Retaining Structure." Applied Mechanics and Materials 166-169 (May 2012): 863–68. http://dx.doi.org/10.4028/www.scientific.net/amm.166-169.863.

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Mechanism of composite pre-reinforced micro pile soil-nail and pure soil-nail retaining structure in foundation-pit engineering are analyzed in this paper through general three dimension nonlinear numerical simulation software. Research contents include whole construction process simulation of construction such as excavation by steps, piles and soil-nail installation and panel manufacture etc. By the comparison of mechanical characteristics between the pure soil-nail and composite soil-nail retaining structures in the same slope engineering example, differences of tension distribution range of soil layer, deformation features, mechanical characteristics of support and axial force distribution along nails etc. are analyzed. Research results are verified by in-site projects and measured data. The action mechanism and working performance of composite soil-nail retaining support are also systematically studied and theoretical basis can be provided in the similar application.

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Junaideen, S. M., L. G. Tham, K. T. Law, C. F. Lee, and Z. Q. Yue. "Laboratory study of soilnail interaction in loose, completely decomposed granite." Canadian Geotechnical Journal 41, no. 2 (April 1, 2004): 274–86. http://dx.doi.org/10.1139/t03-094.

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The technique of soil nailing is seldom used in stabilizing loose fill slopes because there is a lack of understanding of the interaction behaviour of nails in loose fills. A large-scale laboratory apparatus has been built to study the soilnail interaction in loose fill materials. Pullout tests were performed in a displacement-rate-controlled manner on steel bars embedded in loose, completely decomposed granitic soils. The loaddisplacement curves have distinct peak values followed by a sharp decrease in the pullout force. The test results also show that the normal stress acting on the nail changes because of the volume-change tendency and arching effect of the soil being sheared around the nail. The post-peak decrease in the pullout force is mainly due to the reduction in the normal stress caused by the arching effect of soil around the nail. The conventional method of analysis tends to give a low interface friction angle and high interface adhesion. The correct interface parameters can be determined by taking the changes in the normal stress acting on the nail into account.Key words: arching effect, interface friction angle, laboratory test, loose fill, pullout resistance, soilnail interaction.

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Pei, Hua-Fu, Chao Li, Hong-Hu Zhu, and Yu-Jie Wang. "Slope Stability Analysis Based on Measured Strains along Soil Nails Using FBG Sensing Technology." Mathematical Problems in Engineering 2013 (2013): 1–5. http://dx.doi.org/10.1155/2013/561360.

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In the past few decades, slope stability analysis using numerical methods is becoming a hot issue, but it is based on extremely ideal assumptions. Soil nailing technique, as one of the most cost-effective reinforcing methods, has already been widely used for reinforcing slopes. In this study, to evaluate the safety factor of a slope, the strains on soil nails were measured by fiber Bragg grating (FBG) sensor. Strains along soil nails in the same cross section of a slope can be computed using the measured wavelength shifts of FBG sensors. In order to evaluate the stability of a slope, an optimal model was proposed to search the potential slip surfaces based on measured strain values. Maximum sum of strains on soil nails at different elevations of the same cross section was taken as the objective. Positions of soil nails, circular slip surface, and boundary conditions of the soil nails were summarized and taken as constraints. Finally, safety factors can be computed using the searched slip surface regarding the axial stress of soil nails. This method combines the limit equilibrium methods with measured axial strains on site which can reflect the actual condition of field slopes.

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Wikurendra, Edza Aria, Merry Crismiati, and Globila Nurika. "Relation of Parasites in Soil with The Existence of Parasites on Farmer's Nails." Indonesian Journal of Medical Laboratory Science and Technology 3, no. 1 (April 27, 2021): 47–55. http://dx.doi.org/10.33086/ijmlst.v3i1.1850.

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Worms is an infectious disease caused by parasitic worms that can endanger health. Worms that often infect and have a very detrimental impact are soil-borne worm infections or Soil-Transmitted Helminths. Soil-Transmitted Helminths still considered insignificant because it is considered not to cause harm or cause death. This study aims to determine the relationship of parasites in the soil with the presence of parasites on the nails of farmers Sumber Urip 1 Village Wonorejo, East Java, Indonesia. The research method was used observational analytic with a cross-sectional study design which involved 18 Sumber Urip 1 farmers in Wonorejo Village. The sampling technique used was Total Sampling. The bivariate analysis uses Pearson correlation with decision making using significant <0.01. The identification of parasites using the floating method in 18 soil samples contained 12 flattering pieces of hookworm larvae and roundworm eggs. While the results of parasite identification with sedimentation method in 18 nail samples of farmers, there are 11 positive hookworm larvae samples, i.e. Ancylostoma duodenale. The correlation test result showed a relationship between parasites in the soil and nails of Sumber Urip 1 farmers in Wonorejo village (significant as P < 0.01). The use of gloves and footwear (shoes) when working on agricultural land, wash hands with soap and brush nails so that dirt is lost, and consume worm medicine can prevent worms infection.

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Cheng, Zhihe, and Yousheng Deng. "Bearing Characteristics of Moso Bamboo Micropile-Composite Soil Nailing System in Soft Soil Areas." Advances in Materials Science and Engineering 2020 (August 12, 2020): 1–17. http://dx.doi.org/10.1155/2020/3204285.

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Based on the characteristics of moso bamboo including high short-term strength, stable performance, and ability to provide temporary support for shallow foundation pits in soft soil, the stress characteristics and supporting effects of the ecological composite supporting system have been explored through model tests and numerical calculation analysis of the moso bamboo micropile-composite soil nailing structure. The results showed that the bamboo pile can effectively control the horizontal deformation of the side wall of the foundation pit and the ground surface settlement, achieving a relatively satisfactory supporting effect. Furthermore, the bamboo pile has visibly bent in middle and lower parts, where the regional shear point is most likely to appear, the axial force of the soil nail is distributed in an oval pattern with a smaller force on both sides and a larger force in the middle part, the maximum axial strain is 447.3 με, and the axial force of the soil nails in each row follows a similar trend. The synergy of piles and soil nails can delay the formation of the slip surface, therefore enhancing the overall bearing capacity of the foundation pit. These results can shed light on the support mechanism and engineering design of bamboo piles in shallow soft soil foundation pits.

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Nowroozi, Vahid, Hamid Hashemolhosseini, Mohammad Afrazi, and Ehsan Kasehchi. "Optimum Design for Soil Nailing to Stabilize Retaining Walls Using FLAC3D." Journal of Advanced Engineering and Computation 5, no. 2 (June 30, 2021): 108. http://dx.doi.org/10.25073/jaec.202152.329.

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The behavior of a reinforced soil system depends on parameters such as the structural geometry, execution steps, density and mechanical properties of the soil, density of reinforcement materials, deformation, and flexural stiffness of reinforcement materials. A critical parameter in the design of a soil-nailed system is the optimal use of materials with respect to cost. It is necessary to find an optimal design that is cost-effective within the parameters affecting the behavior of the nailed system. A common problem in nailed excavations is an increase in the excavation depth beyond the initial design of the wall, which will require more reinforcements. In this research, we used one approach not used before the method is placing one and two rows of long nails placed at the appropriate depth. In this study, a comparison between safety factor, horizontal displacement, and lateral pressure behind the wall has been made at two nail placement depths using FLAC3D finite difference software that reveals the optimal depth for efficiency is approximately at the middle of the finished wall height. When the number of reinforcement nails with the same lengths was considered, the installation of two rows of nails in comparison with 5 or 3 rows of nails reduced the maximum wall displacement to a greater extent. A greater factor of safety was achieved. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium provided the original work is properly cited.

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Chen, Zhi, Mengke Que, Lifei Zheng, Xiaoqinq Li, and Yang Sun. "Effect of Mortar Constraint Conditions on Pullout Behavior of GFRP Soil Nails." Advances in Materials Science and Engineering 2020 (January 10, 2020): 1–11. http://dx.doi.org/10.1155/2020/4170363.

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Glass fiber reinforced polymer (GFRP) bars are safe, light, and environmentally friendly and, hence, have emerged as desirable alternatives to traditional steel reinforcements in soil nailing wall reinforcement. The loads experienced by GFRP soil nails are transmitted through bonding with mortar and the surrounding soil mass. Constraints of the soil mass on mortar affect the pullout performance of the nails. This paper presents a laboratory test study on the influence of different mortar constraint conditions on the pullout behavior of GFRP soil nails. The results indicated that single loading or cyclic loading has a negligible effect on the failure modes of specimens under different constraints. Therefore, all specimens underwent the same mode of failure, i.e., splitting failure of the mortar. The ultimate pullout force associated with single loading under strong constraint conditions was 77% higher than that under unconstrained conditions, and the anchorage depth increased from 0.6 m to 1.0 m. The load-slip curves obtained for unconstrained conditions and strong constraint conditions were approximately straight lines and double broken lines, respectively. The ultimate tensile stress of GFRP soil nails exceeds the tensile strength of ordinary steel bars, indicating that these nails have sufficient strength reserve.

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Gong, Jie, Priyantha W. Jayawickrama, and Yajai Tinkey. "Nondestructive Evaluation of Installed Soil Nails." Transportation Research Record: Journal of the Transportation Research Board 1976, no. 1 (January 2006): 104–13. http://dx.doi.org/10.1177/0361198106197600112.

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Wang, Hui, Jianhua Cheng, Hujun Li, Zhilin Dun, and Baoquan Cheng. "Full-Scale Field Test on Construction Mechanical Behaviors of Retaining Structure Enhanced with Soil Nails and Prestressed Anchors." Applied Sciences 11, no. 17 (August 27, 2021): 7928. http://dx.doi.org/10.3390/app11177928.

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Soil nailing combined with prestressed anchors has a good workability and is relatively cheap in constraining the horizontal displacement. Current research on the technique, whether theoretical analyses, numerical simulations, or model tests, was conducted under ideal working conditions. However, in fact, external disturbances, such as tensioning-lagging of the anchor, are very common and play an important role on stress and displacement. Therefore, it is of great significance to carry out a field test considering the effects of external disturbances, which can obtain real and reliable data through real-time monitoring. In this paper, the impacts of the construction conditions on practical engineering are discussed based on in situ tests, and some reasonable suggestions for the upgrading of misbehaviors in the current construction situation are put forward. In particular, the influence features of soil predisturbance, excessive excavation, unloading on the surface of edges, tensioning-lagging of the anchor, and continuous rainfall on the stress–time curve of soil nails under practical working conditions are analyzed. Behaviors of three different retaining structures enhanced with (i) soil nails; (ii) soil nails and prestressed anchors without unbonded parts; and (iii) soil nails and prestressed anchors with a 2.5 m unbonded part were monitored during staged excavation to investigate the influences of (i) the prestressing force and (ii) the unbonded part of the prestressed anchors on the performance of the entire retaining system. Results show that (i) the prestressing force is the main factor affecting the stress and deformation of the composite retaining system, which is consistent with the existing literature; (ii) the variation of the magnitude and distribution of the soil nail force responding to the anchor prestressing force, however, showed no systematic trend; and (iii) the unbonded part of anchors, which was validated to be the main factor affecting the structural stability in dense materials in the existing literature, is found to have a minor influence in loose fill materials used in this study.

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Arêdes, Ana Carolina Nascimento de Barros, Eduardo Antonio Gomes Marques, and Angelo Henrique Cruz Oliveira. "Pullout Testing of Soil Nails in Gneissic Residual Soil." Soils and Rocks 43, no. 1 (March 31, 2020): 85–96. http://dx.doi.org/10.28927/sr.431085.

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Zhu, Chang Zhi, and Quan Chen Gao. "On Numerical Simulation of the Stepped Soil-Nail Wall." Applied Mechanics and Materials 353-356 (August 2013): 692–95. http://dx.doi.org/10.4028/www.scientific.net/amm.353-356.692.

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Based on an Engineering Example which was supported by the stepped soil-nail wall, a numerical analysis model was established by FLAC3D,and the process of the excavation and supporting was simulated, and the numerical results of the soil nails internal force and foundation pit deformation were obtained. The simulated result was consistent with the measured results. It shows that the method of FLAC3D numerical analysis can be used to the numerical analysis of foundation pit excavation and supporting, and it will provide the basis for the design and construction of practice project.

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Wang, Qiong, Xinyu Ye, Shanyong Wang, Scott William Sloan, and Daichao Sheng. "Experimental investigation of compaction-grouted soil nails." Canadian Geotechnical Journal 54, no. 12 (December 2017): 1728–38. http://dx.doi.org/10.1139/cgj-2017-0063.

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An innovative compaction-grouted soil nail was designed by injecting grout into a special latex balloon (grouting bag) to avoid bleeding and penetration of grout into the surrounding soil. A series of large-scale model tests was performed to study the surrounding soil responses due to grouting and the subsequent pull-out resistance of the soil nail. The experimental results show that grouting pressure plays an important role in the enhancement of the density and (or) strength of the surrounding soil. In addition, during the pull-out process, the compaction-grouted soil nail exhibits a strain-hardening behaviour without a yield point. This is a significant advantage of this new soil nail, indicating that it can enable soil masses to remain stable against a relatively large deformation before ultimate failure. The main factors behind the improvement of the pull-out resistance of the new soil nail are, first, the compaction–densification of the soil near the grouting bag due to grouting, resulting in the enhancement of the shear strength of the soil, and, second, the enlargement of the grouting bag, causing the increase of the interface shear and end resistance to the pull-out of the soil nail.

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Sharma, Mahesh, Deepankar Choudhury, Manojit Samanta, Shantanu Sarkar, and V. S. Ramakrishna Annapareddy. "Analysis of helical soil-nailed walls under static and seismic conditions." Canadian Geotechnical Journal 57, no. 6 (June 2020): 815–27. http://dx.doi.org/10.1139/cgj-2019-0240.

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The present study investigates the behaviour of helical soil-nailed wall in a dry cohesionless medium under static and seismic conditions. Initially, results from laboratory pullout tests are used to develop a pullout capacity equation, which is subsequently used for stability analysis of helical soil-nailed wall. A detailed parametric study is conducted to evaluate the effect of angle of internal friction of soil, nail inclination, vertical spacing of nails, number of nails, helix size, number of helices, and the face angle on the stability of the soil-nailed wall. Results from the present method are compared and validated with similar existing methods available in the literature. The results suggest that for the given input parameters, the factor of safety (FoS) values from the present method are lower than the pseudo-static and pseudo-dynamic values. Further, the study clearly highlights the significance of input excitation frequency on the FoS of helical soil-nailed walls. In addition, the effects of strain-dependent dynamic properties (shear modulus and damping ratio) on the stability of helical soil-nailed walls are studied using the newly proposed equivalent linear analysis approach. The results computed from the proposed linear and equivalent linear analysis are also compared and discussed in detail.

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Wang, Deng Qun, and Yan Peng Zhu. "Prestressed Anchor Bolt Impact on the Deformation of Composite Soil Nailing." Applied Mechanics and Materials 353-356 (August 2013): 11–15. http://dx.doi.org/10.4028/www.scientific.net/amm.353-356.11.

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Finite element software was employed to establish a model to simulate the compound soil nailing. The model simulates the process of constructing prestressed compound soil nailing. Compared the condition prestressed with no prestress, analyzed the Impact of prestress anchor on the deformation in the process of construction and the effect on axial force of soil nail. Applying prestress is able to control the horizontal displacement obviously, but has not obvious effect on vertical displacement, especially place the anchor bolt at the lower part of the slope. In the process of construction, prestress has an advance effect on the deformation of foundation pit and the axial force of soil nails near the anchor bolt.

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38

Han, Wei, Genxiao Li, Zhaohui Sun, Hengjie Luan, Chuanzheng Liu, and Xianlong Wu. "Numerical Investigation of a Foundation Pit Supported by a Composite Soil Nailing Structure." Symmetry 12, no. 2 (February 6, 2020): 252. http://dx.doi.org/10.3390/sym12020252.

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In special geology conditions such as silt-soil, foundation pits are prone to instability and severe deformation. In this paper, a composite soil nailing structure was studied and its effect on a silt-soil symmetrical foundation pit investigated. The factors affecting the stability of the pit as well as its deformation characteristics were also explored. The results show that excavation depth of the foundation pit has a significant impact on its stability. The soil outside the foundation pit is in the form of a parabola, and the uplift of the soil mainly occurs at the bottom. The horizontal displacement of soil on the side wall of the foundation pit presents a “bulk belly” form. In addition, the axial force of soil nails is larger in the middle part, and smaller at both ends in the shape of a spindle. Moreover, the horizontal displacement is positively correlated with the inclination and spacing of the soil nails, but negatively correlated with the diameter and depth of the mixing pile inlay. Furthermore, the inclination and spacing of the soil nails, the diameter, and embedded depth of the mixing pile have their own critical values for stability of the foundation pit. Specifically, in this paper, with respect to soil nails, inclination should be below 30° and prestress value should not exceed 20 kN. With respect to the mixing pile, the diameter should be less than 1.5 m; when the embedded depth of the mixing pile exceeds the critical depth, the limiting effect of the mixing pile on horizontal displacement is not significant. This research provides important takeaways for the design of a composite soil nailing structure for symmetrical foundation pits.

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Wang, Yong Sheng, and Li Hua Wu. "The Engineering Application of New Method for Calculating Seismic Active Earth Pressure of Soil-Nailing Retaining Structures." Advanced Materials Research 915-916 (April 2014): 86–89. http://dx.doi.org/10.4028/www.scientific.net/amr.915-916.86.

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Based on the method for calculating seismic active earth pressure of soil-nailing retaining structures literature [ , the effect of horizontal seismic coefficient on seismic active earth pressure and the most dangerous sliding are analyzed in connection with practical engineering projects, and compared with the result which is not considered the seismic action. Results show that The existence of soil nails can effectively reduce the lateral pressure of supporting structures under earthquake ground motions and make the sliding surface slowly move to the wall back; Increased along with the height of soil nailing wall;With the increase of the height of soil nailing wall ,facing wall the sliding movement amplitude increase under the action of earthquake, and the soil nail length is growing.

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Zhang, Cheng-Cheng, Hong-Hu Zhu, Qiang Xu, Bin Shi, and Guo-Xiong Mei. "Time-dependent pullout behavior of glass fiber reinforced polymer (GFRP) soil nail in sand." Canadian Geotechnical Journal 52, no. 6 (June 2015): 671–81. http://dx.doi.org/10.1139/cgj-2013-0381.

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Glass fiber reinforced polymer (GFRP) materials are gaining increasing use in geotechnical engineering applications in recent years. The long-term performance of reinforced geostructures may be influenced by the rheological properties of GFRP soil nails or anchors. However, a clear understanding of this effect is lacking. This work aims to investigate the interaction between GFRP soil nail and sand under pullout conditions considering the time-dependent effect. A time-dependent model was proposed to describe the load–deformation characteristics of a GFRP soil nail during pullout. Laboratory pullout tests were performed using a load-controlled pullout apparatus to verify the effectiveness of the proposed model. Quasi-distributed fiber Bragg grating (FBG) optical fiber sensors were adhered on the pre-grooved GFRP soil nail to capture the variations of axial strain during testing. The test results are presented, interpreted, and discussed. It is shown that there is good agreement between the simulation results and the experimental data under low stress levels. Additionally, the impacts of model parameters on the predicted time-dependent pullout behavior of a GFRP soil nail were examined through parametric studies. The results indicate that the distributions of tensile force and GFRP–sand interfacial shear stress along the nail length are highly time dependent. The creep displacement of a GFRP soil nail is significantly influenced by the rheological parameters of the proposed model.

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41

Lin, Peiyuan, Pengpeng Ni, Chengchao Guo, and Guoxiong Mei. "Mapping soil nail loads using Federal Highway Administration (FHWA) simplified models and artificial neural network technique." Canadian Geotechnical Journal 57, no. 10 (October 2020): 1453–71. http://dx.doi.org/10.1139/cgj-2019-0440.

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This study compiles a broad database containing 312 measured maximum soil nail loads under operational conditions. The database is used to re-assess the prediction accuracies of the default Federal Highway Administration (FHWA) nail load model and its modified version previously reported in the literature. Predictions using the default and modified FHWA models are found to be highly dispersive. Moreover, the prediction accuracy is statistically dependent on the magnitudes of the predicted nail load and several model input parameters. The modified FHWA model is then recalibrated by introducing extra empirical terms to account for the influences of wall geometry, nail design configuration, and soil shear strength parameters on the evolvement of nail loads. The recalibrated FHWA model is demonstrated to have much better prediction accuracy compared to the default and modified models. Next, an artificial neural network (ANN) model is developed for mapping soil nail loads, which is shown to be the most advantageous one as it is accurate on average and the dispersion in prediction is low. The abovementioned dependency issue is also not present in the ANN model. The practical value of the ANN model is highlighted by applying it to reliability-based designs of soil nails against internal limit states.

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42

Drumm, E. C., M. Mauldon, and C. R. Tant. "Stabilization of coal mine waste with soil nails." Proceedings of the Institution of Civil Engineers - Ground Improvement 2, no. 4 (October 1998): 147–56. http://dx.doi.org/10.1680/gi.1998.020401.

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Sivakumar Babu, G. L., and Raja Jaladurgam. "Rehabilitation of distressed retaining walls using soil nails." Proceedings of the Institution of Civil Engineers - Ground Improvement 168, no. 1 (February 2015): 22–32. http://dx.doi.org/10.1680/grim.12.00036.

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Mickovski, Slobodan B., Fraser M. Lindsay, and Martyn J. Smith. "Construction and testing of self-drilled soil nails." Proceedings of the Institution of Civil Engineers - Geotechnical Engineering 169, no. 6 (December 2016): 541–53. http://dx.doi.org/10.1680/jgeen.15.00149.

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Babu, G. L. Sivakumar, and Vikas Pratap Singh. "Adequacy of field pullout testing of soil nails." Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards 4, no. 2 (June 2010): 93–98. http://dx.doi.org/10.1080/17499510903439388.

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Babu, G., and Vikas Singh. "Soil nails field pullout testing: evaluation and applications." International Journal of Geotechnical Engineering 4, no. 1 (January 2010): 13–21. http://dx.doi.org/10.3328/ijge.2010.04.01.13-21.

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Milligan, G. W. E., and Kouji Tei. "The Pull-Out Resistance of Model Soil Nails." Soils and Foundations 38, no. 2 (June 1998): 179–90. http://dx.doi.org/10.3208/sandf.38.2_179.

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Zhang, L. L., L. M. Zhang, and W. H. Tang. "Uncertainties of Field Pullout Resistance of Soil Nails." Journal of Geotechnical and Geoenvironmental Engineering 135, no. 7 (July 2009): 966–72. http://dx.doi.org/10.1061/(asce)gt.1943-5606.0000014.

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Shoari Shoar, S. Mohammad, Ali A. Heshmati, and Hossein Salehzadeh. "Prefailure Deformation of Nailed Deep Excavations under Surcharge by Centrifuge Model Test." Advances in Civil Engineering 2021 (August 25, 2021): 1–13. http://dx.doi.org/10.1155/2021/5569797.

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To study prefailure deformations in nailed deep vertical excavations under various surcharges, four centrifuge tests were used to explain the lateral deformation of facing, the fracture mechanism of cement facing, and the settlement profile of the ground surface. The soil used in this research was Firoozkooh sand No. 161. Both surcharge applying and excavation were performed at 40 g acceleration. The depth of the excavation was 30 cm, the length of the nail varied from H/3 to 2H/3 (H: excavation depth), and the nails were installed horizontally. The nails were made of brass pipes and then sand coated. The results showed that the effect of surcharge on the lateral deformation of the facing as well as the fracture mechanism of facing is obvious. Also, it was seen that the ground settlement profile is two-line or three-line at the moment of facing fracture and is affected by surcharge.

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Wang, Bing. "Study on Composite Soil Nailing Wall in Soft Soil Area of Complex Condition with Emphasis on Analysis by Finite Element Analysis." Applied Mechanics and Materials 174-177 (May 2012): 2020–23. http://dx.doi.org/10.4028/www.scientific.net/amm.174-177.2020.

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Based on a typical projects, the horizontal displacement in depth, horizontal displacement and vertical subsidence of pile top, and settlements of surrounding buildings are monitored with the process on digging of deep foundation pit. The study on digging process of foundation pit is analyzed by using finite element software. Using mapped meshing method, from mixing the pile near the semi-circular area (radius = 50m), the meshing appropriate encryption in order to improve the accuracy of the external semi-circular area (radius = 65m) mesh is less appropriate sparse.Layer by layer to kill the layers of the soil unit and activate the soil nails (spring element), the simulated excavation and synchronization of soil nails construction.Verify the arc form of failure surface in side of deep foundation pit in soft soil area. Which is valuable for reference to similar structure engineering of foundation pit.

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Journal articles on the topic 'Soil Nails'

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