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1
Chen, Chuan Sheng, e Hong Bin Xiao. "Liquefaction Potential of Clayey Soils from Wenchuan Earthquake-Induced Landslides". Advanced Materials Research 639-640 (gennaio 2013): 850–53. http://dx.doi.org/10.4028/www.scientific.net/amr.639-640.850.
Testo completoAbstract (sommario):
It is commonly considered that liquefaction of sandy soils is the important reason for earthquake-induced landslides,but it has been reported liquefaction phenomenon can also occur in clayey soils in the recent research. In order to clarify liquefaction potential in clayey soils ,a deeper study was conducted on the basis of field investigation and a series of laboratory tests including undrained cyclic ring-shear tests on the clayey soil samples collected from the sliding zone of the Wenchuan earthquake-induced landslides. Results show that the liquefaction potential of clayey soils is lower than that of sandy soils given the same void ratio; the soil resistance to liquefaction rises with an increase in plasticity for clayey soils; It is useful to estimate the liquefaction potential of soil by means of plasticity index and the liquefaction potential of soil in practical engineering applications.
2
Xu, Qing, Fei Kang e Jun Jie Li. "A Neural Network Model for Evaluating Gravel Liquefaction Using Dynamic Penetration Test". Applied Mechanics and Materials 275-277 (gennaio 2013): 2620–23. http://dx.doi.org/10.4028/www.scientific.net/amm.275-277.2620.
Testo completoAbstract (sommario):
Evaluation of liquefaction potential of soils is important in geotechnical earthquake engineering. Significant phenomena of gravelly soil liquefaction were reported in 2008 Wenchuan earthquake. Thus, further studies on the liquefaction potential of gravelly soil are needed. This paper investigates the potential of artificial neural networks-based approach to assess the liquefaction potential of gravelly soils form field data of dynamic penetration test. The success rates for occurrence and non-occurrence of liquefaction cases both are 100%. The study suggests that neural networks can successfully model the complex relationship between seismic parameters, soil parameters, and the liquefaction potential of gravelly soils.
3
Nategh, Mehrdad, Abdullah Ekinci, Anoosheh Iravanian e Siavash Salamatpoor. "Determination of Initial-Shear-Stress Impact on Ramsar-Sand Liquefaction Susceptibility through Monotonic Triaxial Testing". Applied Sciences 10, n. 21 (3 novembre 2020): 7772. http://dx.doi.org/10.3390/app10217772.
Testo completoAbstract (sommario):
Liquefaction risk assessment is critical for the safety and economics of structures. As the soil strata of Ramsar area in north Iran is mostly composed of poorly graded clean sand and the ground water table is found at shallow depths, it is highly susceptible to liquefaction. In this study, a series of isotropic and anisotropic consolidated undrained triaxial tests were performed on reconstituted specimens of Ramsar sand to identify the liquefaction potential of the area. The specimens are consolidated isotropically to simulate the level ground condition, and anisotropically to simulate the soil condition on a slope and/or under a structure. The various states of soil behavior are studied by preparing specimens at different initial relative densities and applying different levels of effective stress. The critical state soil mechanics approach for identifying the liquefaction susceptibility is adopted and the observed phenomena are further explained in relation to the micro-mechanical behavior. As only four among the 27 conducted tests did not exhibit liquefactive behavior, Ramsar sand can be qualified as strongly susceptible to liquefaction. Furthermore, it is observed that the pore pressure ratio is a good indication of the liquefaction susceptibility.
4
Stewart, Jonathan P., Daniel B. Chu, Raymond B. Seed, Jiann-Wen Ju, William J. Perkins, Ross W. Boulanger, Yao-Chung Chen, Chang-Yu Ou, Joseph Sun e Ming-Shan Yu. "Soil Liquefaction". Earthquake Spectra 17, n. 1_suppl (aprile 2001): 37–60. http://dx.doi.org/10.1193/1.1586192.
Testo completo
5
Alqawasmeh, Hasan, Yazan Alzubi e Ali Mahamied. "State-of-the-Art Review: Fiber-Reinforced Soil as a Proactive Approach for Liquefaction Mitigation and Risk Management". Journal of Engineering 2023 (26 settembre 2023): 1–22. http://dx.doi.org/10.1155/2023/8737304.
Testo completoAbstract (sommario):
Soil liquefaction is a phenomenon that occurs in which the behavior of soils changes from solid to viscous liquid due to the effect of earthquake intensity or other sudden loadings. The earthquake results in excess pore water pressure, which leads to saturated loose soil with weaker characteristics and potentially causes large ground deformation and lateral spreading. Soil liquefaction is a dangerous event that can lead to catastrophic outcomes for humans and infrastructures, especially in countries prone to earthquake shaking, where soil liquefaction is considered one of the most prevalent types of ground failure. Hence, precautions to reduce and/or prevent soil liquefaction are essential and required. One of the countermeasures to avoid soil liquefaction is the introduction of fibers in the soil since fibers can act as reinforcement by enhancing the soil’s strength and resistance to liquefaction. The process of including fibers into the soil is known as soil stabilization and is considered one of the ground improvement techniques. Therefore, this paper aims to summarize and review the consequences of adding fiber as a reinforcement technique to overcome the issue of soil liquefaction.
6
Anderson, Donald J., Kevin W. Franke, Robert E. Kayen, Shideh Dashti e Mahir Badanagki. "The Over-Prediction of Seismically Induced Soil Liquefaction during the 2016 Kumamoto, Japan Earthquake Sequence". Geosciences 13, n. 1 (27 dicembre 2022): 7. http://dx.doi.org/10.3390/geosciences13010007.
Testo completoAbstract (sommario):
Following the M7.0 strike-slip earthquake near Kumamoto, Japan, in April of 2016, most geotechnical engineering experts believed that there would be significant soil liquefaction and liquefaction-induced infrastructure damage observed in the densely populated city of Kumamoto during the post-event engineering reconnaissance. This belief was driven by several factors including the young geologic environment, alluvially deposited soils, a predominance of loose sandy soils documented in publicly available boring logs throughout the region, and the high intensity ground motions observed from the earthquake. To the surprise of many of the researchers, soil liquefaction occurred both less frequently and less severely than expected. This paper summarizes findings from our field, laboratory, and simplified analytical studies common to engineering practice to assess the lower occurrence of liquefaction. Measured in situ SPT and CPT resistance values were evaluated with current liquefaction triggering procedures. Minimally disturbed samples were subjected to cyclic triaxial testing. Furthermore, an extensive literature review on Kumamoto volcanic soils was performed. Our findings suggest that current liquefaction triggering procedures over-predict liquefaction frequency and effects in alluvially deposited volcanic soils. Volcanic soils were found to possess properties of soil crushability, high fines content, moderate plasticity, and unanticipated organic constituents. Cyclic triaxial tests confirm the high liquefaction resistance of these soils. Moving forward, geotechnical engineers should holistically consider the soil’s mineralogy and geology before relying solely on simplified liquefaction triggering procedures when evaluating volcanic soils for liquefaction.
7
Chen, Jian, Tomohide Takeyama, Hideyuki O-Tani, Kohei Fujita, Hiroki Motoyama e Muneo Hori. "Using High Performance Computing for Liquefaction Hazard Assessment with Statistical Soil Models". International Journal of Computational Methods 16, n. 05 (28 maggio 2019): 1840005. http://dx.doi.org/10.1142/s0219876218400054.
Testo completoAbstract (sommario):
Conventional methods for liquefaction assessment using engineering indices such as Factor of safety against Liquefaction (FL) tend to overestimate liquefaction hazards. The soil dynamics analysis-based assessment with automatic modeling is more rational and robust. Soil properties are known for large uncertainties. Rather than deterministic soil models, statistical models for soil parameters should be considered. With automatic modeling, a large number of statistic models can be generated without difficulty. The problem becomes how to assess liquefaction hazard with statistic models in an efficient way. Using high performance computing, we develop an efficient liquefaction assessment method for statistical modeling of soils. A high parallel efficiency can be achieved and a large number of statical models of the order of 104 can be simulated within a reasonable time span. The method developed in this paper can be used as an efficient tool for unravelling critical parameters of soil liquefaction.
8
Xu, Binhua, Ning He e Denghua Li. "Study on the treatments and countermeasures for liquefiable foundation". MATEC Web of Conferences 272 (2019): 01012. http://dx.doi.org/10.1051/matecconf/201927201012.
Testo completoAbstract (sommario):
This paper summarizes the current treatments and countermeasures for liquefiable foundations, and divides the existing anti-liquefaction countermeasures into two categories. One of the ideas is proceeding from the properties of liquefiable foundation soils, by the means of improvement for the soil’s qualities to enhance the capacity of soil’s anti-liquefaction in the early stage. The other idea is considering from the stress conditions of liquefiable foundation soils, and to reduce the liquefaction-induced disasters by changing the stress conditions of the soil. The advantages and disadvantages of various anti-liquefaction measures were analysed by verifying the effectiveness of field applications of anti-liquefaction measures against ground liquefaction hazards, and the applicable conditions of various anti-liquefaction measures were classified. This paper provides experience for resisting soil liquefaction disasters.
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Rahman, Arif. "Effect of grain shape to potential liquefaction". E3S Web of Conferences 156 (2020): 02014. http://dx.doi.org/10.1051/e3sconf/202015602014.
Testo completoAbstract (sommario):
Earthqueke is one of the most frequent disaster in Indonesia, Earthqueke have caused losses both in terms of life and material. An earthquake also can trigger to soil liquefaction. Attention to liquefaction in Indonesia has raised after the Palu Earthquake in 2018. Liquefaction may happen in sandy soil in certain condition. Here, a series laboratory tests to study potentially liquefied in sandy soils is conducted. The liquefaction potential of sand are analyzed with the effect of the shape of the soil particles. The sandy sample is made up by special selected in three different shapes that are sharp, angular and round. Finally, it can be seen the effect of the shape of the soil grain on the liquefaction potential. The results of this study can be used to further investigation in order to mitigate the liquefaction.
10
Chien, Lien-Kwei, Yan-Nam Oh e Chih-Hsin Chang. "Effects of fines content on liquefaction strength and dynamic settlement of reclaimed soil". Canadian Geotechnical Journal 39, n. 1 (1 febbraio 2002): 254–65. http://dx.doi.org/10.1139/t01-083.
Testo completoAbstract (sommario):
In this study, the reclaimed soils in the Yunlin area of west Taiwan are adopted as test samples. The specimens were prepared by moist tamping at different relative densities and fines contents. Triaxial liquefaction tests were performed to evaluate the liquefaction strength and liquefaction-induced settlement. The test results show that the liquefaction strength of reclaimed soil increases as the relative density increases. In addition, under constant relative density, the liquefaction strength decreases as the fines content increases. Based on the test results and one-dimensional consolidation theory, the volumetric strain and settlement can be evaluated by dry density and fines content of the reclaimed soil. The results show that the settlement ratio decreases as the relative density increases. The figures and results can be references for the evaluation of liquefaction strength and liquefaction-induced settlement. The results are useful for liquefaction strength and settlement analysis for planning, design, and related research on land reclamation engineering.Key words: reclaimed soil, liquefaction resistance, fines content, settlement.
11
Fei-hong, Gu. "Evaluation of Soil Liquefaction in Harbor District in Tianjin City". Open Civil Engineering Journal 10, n. 1 (25 maggio 2016): 293–300. http://dx.doi.org/10.2174/1874149501610010293.
Testo completoAbstract (sommario):
The liquefaction of soils in the harbor district in Tianjin City near Tangshan, where a great earthquake occurred is a very important issue related to the soil’s compaction, grain composition and content of clay particle. This problem has not been fully considered due to the complexity and uncertainty of the soil properties data, since none of the previous investigations has been concerned about the liquefaction characteristics of this new harbor district. The evaluation of soil liquefaction has been made based on related data of the standard penetration test (SPT) from 26 investigation bore holes and 105 sieving tests. The results show that the liquefaction index of silt sand gradually decreases with the increase of the buried depth; soils less than 10.6 m in depth are of bad gradation identically. Soil less than 10.6 m in depth can be defined as liquefied soil which is further verified by sieving tests. Both the buried depth and particle grading have primarily significant influences on silt sands’ liquefaction. The results from sieve tests based on liquefied soils were found to fit well with the Tsuchida curves. It is believed that even without the in-suit SPT tests, Tsuchida boundary curves can be directly utilized to judge the liquefaction of soils in the harbor district.
12
Jakka, Ravi Sankar, Amit Shiuly e Ranjit Das. "Liquefaction Potential for Kolkata City". International Journal of Geotechnical Earthquake Engineering 4, n. 2 (luglio 2013): 18–33. http://dx.doi.org/10.4018/ijgee.2013070102.
Testo completoAbstract (sommario):
This paper presents the liquefaction potential of densely populated Kolkata city, which is situated on the world's largest delta island with very soft and thick alluvial soil deposits. Due to presence of soft alluvium deposits at shallow depths, soil resistance against liquefaction is expected to be less. Additionally, large thickness of soil layers may amplify the ground shaking resulting in high seismic demand on the soil. Here in this study, variation of factor of safety against liquefaction is evaluated with depth at different locations in Kolkota city. The study founds striking results that the Kolkata city soils are less prone to liquefaction even though there is significant ground amplification due to presence of thick soil deposits.
13
Morgunov, K. P., e M. A. Kolosov. "Soil Liquefaction Problems in the Foundations Hydraulic Structures". Science & Technique 21, n. 3 (1 giugno 2022): 201–10. http://dx.doi.org/10.21122/2227-1031-2022-21-3-201-210.
Testo completoAbstract (sommario):
An analysis of the probability and conditions for the occurrence of soil liquefaction at the base and in the vicinity of hydraulic structures is presented in the paper. As a rule, hydraulic structures are erected in the valleys of watercourses, the structure of the soil in which contributes to the occurrence of liquefaction processes. These soils are fine-grained, non-cohesive, usually consisting of fine- and medium-grained or silty sands, sandy loams, interspersed with layers of loams. Massifs under pressure hydraulic structures are quite water-saturated. Soil liquefaction occurs as a result of the destruction of structural bonds between particles in water-saturated dispersed soils under the action of stresses of various types. An external dynamic or static load applied to a water-saturated massif composed of weak, finely dispersed soils can lead to a complete or partial loss of soil bearing capacity and its transition to a fluid state. The magnitude of soil resistance to shear is determined by the degree of its water saturation; at a moisture content of about 20 %, the angle of repose of sandy soils is significantly reduced. The restoration of the strength properties of soils is prevented by the pore water pressure, the process of compaction (consolidation) of the soil mass occurs after the water is squeezed out of the pores, the flow time of which depends on the filtration properties of the massif. Liquefaction of soils leads to a disruption in the normal functioning of a hydraulic structure, the creation of emergency situations. The paper provides examples of accidents at hydraulic structures in Russia caused by liquefaction phenomena. It is noted that the main directions of protecting the structures of hydraulic structures from dangerous liquefaction are to prevent the possibility of liquefaction and the reduction of its harmful effects. In this regard, several methods are considered – compaction and strengthening of soils at the base of structures; filtering surcharge device using geotextiles and geogrids; creation of an effective drainage system.
14
Robertson, P. K., e CE (Fear) Wride. "Evaluating cyclic liquefaction potential using the cone penetration test". Canadian Geotechnical Journal 35, n. 3 (1 giugno 1998): 442–59. http://dx.doi.org/10.1139/t98-017.
Testo completoAbstract (sommario):
Soil liquefaction is a major concern for structures constructed with or on sandy soils. This paper describes the phenomena of soil liquefaction, reviews suitable definitions, and provides an update on methods to evaluate cyclic liquefaction using the cone penetration test (CPT). A method is described to estimate grain characteristics directly from the CPT and to incorporate this into one of the methods for evaluating resistance to cyclic loading. A worked example is also provided, illustrating how the continuous nature of the CPT can provide a good evaluation of cyclic liquefaction potential, on an overall profile basis. This paper forms part of the final submission by the authors to the proceedings of the 1996 National Center for Earthquake Engineering Research workshop on evaluation of liquefaction resistance of soils.Key words: cyclic liquefaction, sandy soils, cone penetration test
15
Li, Heng, Zhao Duan, Chenxi Dong, Fasuo Zhao e Qiyao Wang. "Impact-Induced Liquefaction Mechanism of Sandy Silt at Different Saturations". Advances in Civil Engineering 2021 (29 marzo 2021): 1–14. http://dx.doi.org/10.1155/2021/6686339.
Testo completoAbstract (sommario):
Landslide-induced liquefaction has received extensive attention from scholars in recent years. In the study of loess landslides in the southern Loess Plateau of Jingyang, some scholars have noted the liquefaction of the near-saturated sandy silt layer that is caused by the impact of loess landslides on the erodible terrace. The impact-induced liquefaction triggered by landslides is probably the reason for the long-runout landslides on the near-horizontal terrace. In order to reveal the mechanism of impact-induced liquefaction, this paper investigates the development of pore pressure and the impact-induced liquefaction of sandy silt under the influence of saturation through laboratory experiments, moisture content tests, and vane shear tests. It has been found that both the total pressure and pore water pressure undergo a transient increase and decrease at the moment of impact on the soil, which takes 40–60 ms to complete and only about 20 ms to arrive at the peak. Moreover, silty sand with a saturation of more than 80° was liquefied under the impact, and the liquefaction occurred in the shallow layer of the soil body. The shear strength of the liquefied part of the soil is reduced to 1.7∼2.8 kPa. Soils with lower saturation did not liquefy. The mechanism of the impact-induced liquefaction can be described as follows: under impact, the water in the soil gradually fills the pores of the soil body as the pore size decreases, and when the contact between the soil particles is completely replaced by pore water, the soil body loses its shear strength and reaches a liquefied state. Soils in the liquefied state have a very high permeability coefficient, and the water inside the soil body migrates upward as the particles settle, resulting in high-moisture content in the upper soil.
16
Nakano, Takayuki. "Semi-automated landform classification for hazard mapping of soil liquefaction by earthquake". Proceedings of the ICA 1 (16 maggio 2018): 1–6. http://dx.doi.org/10.5194/ica-proc-1-80-2018.
Testo completoAbstract (sommario):
Soil liquefaction damages were caused by huge earthquake in Japan, and the similar damages are concerned in near future huge earthquake. On the other hand, a preparation of soil liquefaction risk map (soil liquefaction hazard map) is impeded by the difficulty of evaluation of soil liquefaction risk. Generally, relative soil liquefaction risk should be able to be evaluated from landform classification data by using experimental rule based on the relationship between extent of soil liquefaction damage and landform classification items associated with past earthquake. Therefore, I rearranged the relationship between landform classification items and soil liquefaction risk intelligibly in order to enable the evaluation of soil liquefaction risk based on landform classification data appropriately and efficiently. And I developed a new method of generating landform classification data of 50-m grid size from existing landform classification data of 250-m grid size by using digital elevation model (DEM) data and multi-band satellite image data in order to evaluate soil liquefaction risk in detail spatially. It is expected that the products of this study contribute to efficient producing of soil liquefaction hazard map by local government.
17
Ghunake, Mr Shubham. "Analysis of Soil Liquefaction Potential through Field Tests Based Method". International Journal for Research in Applied Science and Engineering Technology 11, n. 6 (30 giugno 2023): 2779–84. http://dx.doi.org/10.22214/ijraset.2023.54144.
Testo completoAbstract (sommario):
Abstract: Liquefaction is the phenomena when there is loss of strength in saturated and cohesion-less soils because of increased pore water pressures and hence reduced effective stresses due to dynamic loading. It is a phenomenon inwhich the strength and stiffness of a soil is reduced by earthquake shaking or other rapid loading. The recent increase in Landslides and the repeated evidence of ground failure due to liquefaction motivated this research project. Liquefaction is a soil mechanics problem that often impacts structures that are supported on saturated sanddeposits. The large deformations of the foundation soils typically cause major failures of civil engineering structures. This project involved research of the liquefaction phenomena and the impact experienced on select recent landslides
18
CHE, AILAN, XIANQI LUO, JINGHUA QI e DEYONG WANG. "STUDY ON CORRELATION BETWEEN SHEAR WAVE VELOCITY AND GROUND PROPERTIES FOR GROUND LIQUEFACTION INVESTIGATION OF SILTS". International Journal of Modern Physics B 22, n. 31n32 (30 dicembre 2008): 5705–10. http://dx.doi.org/10.1142/s0217979208051042.
Testo completoAbstract (sommario):
Shear wave velocity (V s ) of soil is one of the key parameters used in assessment of liquefaction potential of saturated soils in the base with leveled ground surface; determination of shear module of soils used in seismic response analyses. Such parameter can be experimentally obtained from laboratory soil tests and field measurements. Statistical relation of shear wave velocity with soil properties based on the surface wave survey investigation, and resonant column triaxial tests, which are taken from more than 14 sites within the depth of 10 m under ground surface, is obtained in Tianjin (China) area. The relationship between shear wave velocity and the standard penetration test N value (SPT-N value) of silt and clay in the quaternary formation are summarized. It is an important problem to research the effect of shear wave velocity on liquefaction resistance of saturated silts (sandy loams) for evaluating liquefaction resistance. According the results of cyclic triaxial tests, a correlation between liquefaction resistance and shear wave velocity is presented. The results are useful for ground liquefaction investigation and the evaluation of liquefaction resistance.
19
Zango, Muttaqa Uba, Khairul Anuar Kassim e Abubakar Sadiq Mohammed. "Bio-desaturation and bio-sealing techniques for mitigation of soil liquefaction: a review". MATEC Web of Conferences 250 (2018): 01018. http://dx.doi.org/10.1051/matecconf/201825001018.
Testo completoAbstract (sommario):
Biogeotechnology is a recent area of study that deals with the improvement of engineering properties of soils in an eco-friendly and sustainable approach through the use of microorganisms. This paper first, reviewed the concept of bio-mediated soil improvement technique, components involved and the roles they played. Two processes of bio-mediation soil improvement techniques i.e. microbial-induced calcite precipitation (MICP) for producing bio-cement via ureolysis and bio-desaturation for generating specifically biogenic nitrogen gas via denitrification, their mechanisms of occurring and factors influencing them were described in details. An overview study was done on soil liquefaction. Conventional methods employed for mitigations of liquefaction hazards were reviewed and their limitations were drawn. The use of the de-saturation process for mitigation of soil liquefaction was adequately addressed. Mitigation of liquefaction using biological processes, in particular, MICP and/or bio-desaturation were introduced. The findings from the previous works have shown that both the two techniques are capable of improving liquefaction resistance of soils. Most of the results have shown that presence of biogenic nitrogen gas in soils treated with denitrifying bacteria is able to induce partial desaturation in the soil which consequently increases the cyclic shear strength, reduces pore water pressure and changes the soil behaviour from compressive to dilatant. Finally, potentials, challenges, and recommendations for future studies were identified.
20
Ahmad, Mahmood, Xiao-Wei Tang, Jiang-Nan Qiu e Feezan Ahmad. "Interpretive Structural Modeling and MICMAC Analysis for Identifying and Benchmarking Significant Factors of Seismic Soil Liquefaction". Applied Sciences 9, n. 2 (10 gennaio 2019): 233. http://dx.doi.org/10.3390/app9020233.
Testo completoAbstract (sommario):
Seismic soil liquefaction is considered as one of the most complex geotechnical earthquake engineering problems owing to the uncertainty and complexity involved in soil parameters, seismic parameters, and site condition factors. Each one of these parameters contains a variety of factors that trigger liquefaction and have varying degrees of importance. However, estimating accurate and reliable liquefaction-induced hazards requires identification and benchmarking of the most influential factors that control soil liquefaction. Seismic soil liquefaction factors were identified by Systematic Literature Review (SLR) approach and analyzed through Interpretive Structural Modeling (ISM) and the Cross-Impact Matrix Multiplication Applied to Classification (MICMAC) methodologies. The ISM model presented the relationships between fifteen seismic soil liquefaction factors and their benchmarking position from higher to lower-level significant factors in hierarchy. MICMAC is used to examine the strength of the relationship between seismic soil liquefaction significant factors based on their driving and dependence power. This research characterizes the identification and benchmarking of the seismic soil liquefaction factors and their relationships. The results show that the factors—duration of earthquake, peak ground acceleration, drainage condition, and standard penetration test (SPT) blow counts—influence seismic soil liquefaction directly and soil type is the governing factor that forms the base of the ISM hierarchy and consequently triggers seismic soil liquefaction. The results provide a more accurate way of selecting significant factors for establishment of seismic soil liquefaction potential and liquefaction-induced hazards risk assessment models.
21
Torres, Emerzon, e Jonathan Dungca. "Prediction of Soil Liquefaction Triggering Using Rule-Based Interpretable Machine Learning". Geosciences 14, n. 6 (6 giugno 2024): 156. http://dx.doi.org/10.3390/geosciences14060156.
Testo completoAbstract (sommario):
Seismic events remain a significant threat, causing loss of life and extensive damage in vulnerable regions. Soil liquefaction, a complex phenomenon where soil particles lose confinement, poses a substantial risk. The existing conventional simplified procedures, and some current machine learning techniques, for liquefaction assessment reveal limitations and disadvantages. Utilizing the publicly available liquefaction case history database, this study aimed to produce a rule-based liquefaction triggering classification model using rough set-based machine learning, which is an interpretable machine learning tool. Following a series of procedures, a set of 32 rules in the form of IF-THEN statements were chosen as the best rule set. While some rules showed the expected outputs, there are several rules that presented attribute threshold values for triggering liquefaction. Rules that govern fine-grained soils emerged and challenged some of the common understandings of soil liquefaction. Additionally, this study also offered a clear flowchart for utilizing the rule-based model, demonstrated through practical examples using a borehole log. Results from the state-of-practice simplified procedures for liquefaction triggering align well with the proposed rule-based model. Recommendations for further evaluations of some rules and the expansion of the liquefaction database are warranted.
22
Pamuk, Ahmet, Patricia Gallagher e Korhan Adalier. "Soil Grouting as Seismic Liquefaction Countermeasure". Advanced Materials Research 1025-1026 (settembre 2014): 1035–40. http://dx.doi.org/10.4028/www.scientific.net/amr.1025-1026.1035.
Testo completoAbstract (sommario):
This paper presents a series of centrifuge tests studying the performance of colloidal silica grouted soil layers during permanent lateral ground deformations due to earthquake induced lateral spreading. Two centrifuge tests were conducted to study liquefaction resistance of liquefiable soil deposits stabilized with colloidal silica, and then the results were compared with the tests conducted on similar soil deposits without any soil remediation. The testing results on remediated soils showed excellent resistance against the liquefaction and associated lateral and vertical ground deformations.
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Donavalli, Jahnavi, T. S. Ram Babu e Chukka Sandhya Rani. "Probability based Assessment of Soil Liquefaction Potential in Vijayawada Region (CRDA)". IOP Conference Series: Earth and Environmental Science 1130, n. 1 (1 gennaio 2023): 012036. http://dx.doi.org/10.1088/1755-1315/1130/1/012036.
Testo completoAbstract (sommario):
Abstract Risks of liquefaction are commonly related to saturated cohesionless soils that have low plasticity and density. As liquefaction causes severe destruction to structures and risk of losing lifeline it is important to study the liquefaction potential for CRDA region because for the development of AP capital heavy structures are being constructed and a population increase is being expected in this region. In the current investigation, soil resistance to liquefaction was analyzed in each bore log in consideration of significant soil characteristics such as grain size, fines content, unit weight, saturation percentage, SPT N-value, and soil origin. The safety factor for liquefaction is evaluated using data from several bore holes that were collected and used for this purpose. The approach recommended by Seed and Idriss was utilized to assess the safety factor for liquefaction. The obtained results from the semi-empirical calculations are further compared to the results obtained from Software for more reliability.
24
Touijrate, Soukaina, Khadija Baba, Mohamed Ahatri e Lahcen Bahi. "Validation and Verification of Semi-Empirical Methods for Evaluating Liquefaction Using Finite Element Method". MATEC Web of Conferences 149 (2018): 02028. http://dx.doi.org/10.1051/matecconf/201814902028.
Testo completoAbstract (sommario):
Liquefaction is a hazardous and temporary phenomenon by which a soil saturated with water loses some or all of its resistance. The undrained conditions and a cyclic load increase the pores water pressure inside the soil and therefore a reduction of the effective stress. Nowadays many semi-empirical methods are used to introduce a proposition to evaluate the liquefaction's potential using the in-situ test results. The objective of this paper is to study their ability to correctly predict the liquefaction potential by modelling our case using finite element methods. The study is based on the data of Cone Penetration Tests experimental results of the Casablanca-Tangier High-Speed Line exactly between PK 116 + 450 and PK 116 + 950 and near of Moulay-Bousselham city. It belongs to the Drader-Soueir basin region which is located in the North-West of Morocco. This region had a specific soil’s formation, the first 50 meters are characterised by the existence of sand layers alternating with layers of clay. These formations are very loose and saturated which suggests the possibility of soil liquefaction. We present and discuss the results of applying the Olsen method [1], the Juang method [2] and the Robertson method [3], in the evaluation of liquefaction susceptibility. Apart from the previous empirical analysis to evaluate the liquefaction potential, numerical modelling is performed in this study.
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Maulana, Arif, Rifa’i Ahmad e Faris Fikri. "Liquefaction potential analysis on runway construction based on soil engineering properties". E3S Web of Conferences 156 (2020): 02003. http://dx.doi.org/10.1051/e3sconf/202015602003.
Testo completoAbstract (sommario):
The term of liquefaction refers to a liquefied soil phenomenon during an earthquake causing the loss of soil bearing capacity. In general, liquefaction occurs in loose sandy soil with saturated condition triggered by an earthquake with Peak Ground Acceleration greater than 0.25 g. This research aim to analyze the liquefaction potential of runway construction which located on loose sandy soil area. The analysis of liquefaction potential is based on borelog data, grain size distribution, soil physical properties, and earthquake risk map. The liquefaction potential was obtained by calculating the liquefaction probability in one dimension analysis determined as safety factor. Settle 3D is also applied in this research. The results show that the liquefaction potentially occurs in sand soil layer at 0-6 meters depth with safety factor 0.11-1.06 from manual calculation and 0.19-1.1 from Settle 3D. This result represents high probability of liquefaction at runway construction area, so that the liquefaction prevention method is needed.
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Yuliet, R., A. L. Silvy, A. Hakam, Fauzan, M. Mera e S. Syuhada. "The influence of various parameters of physical and mechanical properties on susceptibility to liquefaction of sandy soils". IOP Conference Series: Earth and Environmental Science 1173, n. 1 (1 maggio 2023): 012021. http://dx.doi.org/10.1088/1755-1315/1173/1/012021.
Testo completoAbstract (sommario):
Abstract On September 30, 2009, there was liquefaction in the sandy soils around the coast of Padang city, which was triggered by an earthquake measuring 7.6 SR. Liquefaction causes land subsidence and lateral displacement of many buildings in Padang. The level of liquefaction vulnerability of Padang city is in the moderate zone based on qualitative methods; on the contrary, quantitative methods obtained a very high level of vulnerability to liquefaction. Based on this, quantitative methods by conducting geotechnical investigations in the field and laboratory tests are needed to determine the liquefaction potential. This study aims to determine the potential for liquefaction using quantitative methods based on testing the physical properties and mechanical properties of sandy soils in the laboratory. The standard for laboratory testing is the Indonesian National Standard (SNI), and soil sampling was carried out in seventeen areas. The results of the physical and mechanical properties, i.e., relative density (Dr), the particle size of the soil, and internal friction angle, showed that the sandy soils along the coast in Padang are poorly graded sand (SP). The sandy soils are dominated by fine sand with a very loose consistency, which has potential liquefaction.
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Bacic, Bozana, e Ivo Herle. "Soil liquefaction as an identification test". E3S Web of Conferences 92 (2019): 08008. http://dx.doi.org/10.1051/e3sconf/20199208008.
Testo completoAbstract (sommario):
Time-consuming and complicated investigations of soil liquefaction in cyclic triaxial tests are the most common way of laboratory analysis of this phenomenon. Moreover, the necessary equipment for the performance of cyclic triaxial tests is very expensive. Much simpler method for laboratory testing of the soil liquefaction has been developed at the Institute of Geotechnical Engineering at the TU Dresden. This method takes into account the pore water pressure build-up during cyclic shearing within a short time period. During the test, the soil sample is subjected to horizontal cyclic loading and the generated pore water pressure is measured. In the first series of these experiments, a dependence of the pore water pressure buildup on the initial density of soil could be observed, as expected. When comparing different soils, it is shown that the tendency to liquefaction depends also on the granulometric properties (e.g. grain size distribution) of the soil. The aim of the further development is to establish a simple identification test for laboratory testing of the soil liquefaction.
28
Johari, Ali, Jaber Rezvani Pour e Akbar Javadi. "Reliability analysis of static liquefaction of loose sand using the random finite element method". Engineering Computations 32, n. 7 (5 ottobre 2015): 2100–2119. http://dx.doi.org/10.1108/ec-07-2014-0152.
Testo completoAbstract (sommario):
Purpose – Liquefaction of soils is defined as significant reduction in shear strength and stiffness due to increase in pore water pressure. This phenomenon can occur in static (monotonic) or dynamic loading patterns. However, in each pattern, the inherent variability of the soil parameters indicates that this problem is of a probabilistic nature rather than being deterministic. The purpose of this paper is to present a method, based on random finite element method, for reliability assessment of static liquefaction of saturated loose sand under monotonic loading. Design/methodology/approach – The random finite element analysis is used for reliability assessment of static liquefaction of saturated loose sand under monotonic loading. The soil behavior is modeled by an elasto-plastic effective stress constitutive model. Independent soil parameters including saturated unit weight, peak friction angle and initial plastic shear modulus are selected as stochastic parameters which are modeled using a truncated normal probability density function (pdf). Findings – The probability of liquefaction is assessed by pdf of modified pore pressure ratio at each depth. For this purpose pore pressure ratio is modified for monotonic loading of soil. It is shown that the saturated unit weight is the most effective parameter, within the selected stochastic parameters, influencing the static soil liquefaction. Originality/value – This research focuses on the reliability analysis of static liquefaction potential of sandy soils. Three independent soil parameters including saturated unit weight, peak friction angle and initial plastic shear modulus are considered as stochastic input parameters. A computer model, coded in MATLAB, is developed for the random finite element analysis. For modeling of the soil behavior, a specific elasto-plastic effective stress constitutive model (UBCSAND) was used.
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Akhila M., Rangaswamy K. e Sankar N. "Liquefaction Susceptibility of Silty Sands and Low Plastic Clay Soils". International Journal of Geotechnical Earthquake Engineering 10, n. 2 (luglio 2019): 1–17. http://dx.doi.org/10.4018/ijgee.2019070101.
Testo completoAbstract (sommario):
The present study evaluates the liquefaction susceptibility of non-plastic silty sands and low plastic clay soils at different cyclic stress levels under undrained triaxial loading conditions. Six different types of soil combinations were prepared after blending the silt and clay fractions into the fine sand. Silty sands contain up to 40% non-plastic fines and low plastic clays comprise 10-20% clay fraction. The cylindrical soil specimens were constituted at the medium relative density and isotropically consolidated at 100 kPa pressure. The consolidated specimens were subjected to cyclic stress amplitudes of 0.127, 0.152 and 0.178 using sinusoidal wave loading at a frequency of 1 Hz. Results were presented in terms of pore pressure build-up and axial strain propagation with load cycles, and liquefaction resistance curves. It was found that the non-plastic silty sands and soil mixtures with plasticity indices up to 15 are more susceptible to liquefaction than the fine sands. The criterion on liquefaction susceptibility of low plastic soil mixtures shows that the soil mixtures with plasticity indices up to 15 containing 20% plastic fines exhibit a sand-like behavior and show higher liquefaction susceptibility than fine sands. It is worthy to note that the low plastic soil mixtures with PI ≥ 10 are more resistant to liquefaction than the silty sands (those contain up to 40% non-plastic fines).
30
Bziaz, Mohamed, Lahcen Bahi, Latifa Ouadif, Anas Bahi, Hamou Mansouri, Abdelhalim Douiri e Mimoun Abbach. "Evaluation of post liquefaction settlement and treatment and reinforcement of the soil by stone columns". International Journal of Innovative Research and Scientific Studies 6, n. 1 (26 dicembre 2022): 102–14. http://dx.doi.org/10.53894/ijirss.v6i1.1113.
Testo completoAbstract (sommario):
During earthquakes, the shear strength and bearing capacity of saturated sandy soils decreases; this is related to an increase in pore pressure. In the ultimate state, the pore pressure becomes equal to the initial effective stress, at which time the material loses all its resistance and liquefaction occurs. Thus, the prediction of the post-liquefaction settlement of the soil is an important step to reduce the seismic risk. Several methods have been developed for the prediction of Seismic-Induced Settlement, the most widely used is that based on the results of in-situ tests SPT, and Several soil reinforcement techniques can be considered, the choice depends mainly on the grain size of the soil to be treated. This article presents a comparative study of the methods for evaluating Seismic-Induced Settlement based on the experimental results of the in situ SPT tests, applied to an earthquake-prone area in northern Morocco which had specific soil formations characterized by the existence of layers of sand over several meters, which suggests the possibility of soil liquefaction and proposes a method of reducing the risk of liquefaction. The analysis of existing SPT data leads to interesting conclusions both in terms of the comparative analysis of methods for the prediction of the post-liquefaction settlement and the understanding of the effect of Soil treatments by Stone Columns to mitigate the risk of liquefaction.
31
Dief, Hesham M., e J. Ludwig Figueroa. "Liquefaction assessment by the unit energy concept through centrifuge and torsional shear tests". Canadian Geotechnical Journal 44, n. 11 (novembre 2007): 1286–97. http://dx.doi.org/10.1139/t07-059.
Testo completoAbstract (sommario):
The fundamentals of the energy concept to assess the liquefaction potential of cohesionless soils have been formulated in recent years. To examine the validity of this procedure, a series of centrifuge liquefaction tests were carried out using the same soils that were tested previously as part of extensive research conducted on the subject at Case Western Reserve University. A total of 30 liquefaction tests at accelerations of 50g and 60g were conducted on scaled pore fluid saturated models, prepared in a laminar box, representing a prototype soil deposit. The influence of relative density and effective confining pressure, as well as the effect of different grain size distribution on the energy per unit volume required for liquefaction, is studied. Generalized relationships were obtained by performing regression analyses between the energy per unit volume at the onset of liquefaction and liquefaction affecting parameters. These equations are compared with similar ones that were developed previously using torsional shear tests. A rational procedure to determine site response to earthquake loading and liquefaction susceptibility of a soil deposit is verified.
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Ahmad, Mahmood, Xiao-Wei Tang, Feezan Ahmad e Arshad Jamal. "Assessment of Soil Liquefaction Potential in Kamra, Pakistan". Sustainability 10, n. 11 (15 novembre 2018): 4223. http://dx.doi.org/10.3390/su10114223.
Testo completoAbstract (sommario):
In seismically active regions, soil liquefaction is a serious geotechnical engineering problem that mainly occurs in saturated granular soils with a shallow groundwater table. Significant seismic hazards are present in Kamra, Pakistan. With the rapid increase in construction in recent years, the evaluation of liquefaction is now considered to be more important for land use planning and development. The intent of this study is to highlight soil liquefaction susceptibility that will eventually support the national authorities in developing guidelines for sustainable development and the mitigation of liquefaction. The typical subsoil profile of Kamra consists of silty gravel (GM) overlain by silty sand (SM), poorly graded sand (SP), and fill layers. Kamra is close to the active Ranja–Khairabad fault with a peak ground acceleration of 0.24g. The river Sehat and the Ghazi Brotha canal pass through the study area. In this study, the soil liquefaction potential in Kamra was assessed at 10 different sites (50 boreholes) by using a stress-based procedure for calculating the factor of safety against soil liquefaction. The results revealed that the middle layers, i.e., poorly graded sand and silty sand in the subsoil profile, are extremely susceptible to liquefaction during earthquakes with magnitudes between 7.5 and 8.0 in Kamra. The correlation between the factor of safety and the equivalent clean-sand-corrected standard penetration test (SPT) blow counts according to the earthquake magnitudes was developed and can also be utilized for areas adjoining Kamra that have the same subsoil profile.
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Umar, Sujeet Kumar, Pijush Samui e Sunita Kumari. "Reliability Analysis of Liquefaction for Some Regions of Bihar". International Journal of Geotechnical Earthquake Engineering 9, n. 2 (luglio 2018): 23–37. http://dx.doi.org/10.4018/ijgee.2018070102.
Testo completoAbstract (sommario):
There are many deterministic and probabilistic liquefaction assessment measures to classify if soil liquefaction will take place or not. Different approaches give dissimilar safety factor and liquefaction probabilities. So, reliability analysis is required to deal with these different uncertainties. This paper describes a reliability technique for predicting the seismic liquefaction potential of soils of some areas at Bihar State. Here a reliability approach has been presented in order to find the probability of liquefaction. The proposed approach is formulated on the basis of the results of reliability analyses of 234 field data. Using a deterministic simplified Idriss and Boulanger method, factor of safety of soil has been accessed. The reliability index as well as corresponding probability of liquefaction has been determined based on a First Order Second Moment (FOSM) method. The developed method can be used as a robust tool for engineers concerned in the estimation of liquefaction potential.
34
Pham, Tuan Anh. "Application of Feedforward Neural Network and SPT Results in the Estimation of Seismic Soil Liquefaction Triggering". Computational Intelligence and Neuroscience 2021 (18 ottobre 2021): 1–14. http://dx.doi.org/10.1155/2021/1058825.
Testo completoAbstract (sommario):
Soil liquefaction is a dangerous phenomenon for structures that lose their shear strength and soil resistance, occurring during seismic shocks such as earthquakes or sudden stress conditions. Determining the liquefaction and nonliquefaction capacity of soil is a difficult but necessary job when constructing structures in earthquake zones. Usually, the possibility of soil liquefaction is determined by laboratory tests on soil samples subjected to dynamic loads, and this is time-consuming and costly. Therefore, this study focuses on the development of a machine learning model called a Forward Neural Network (FNN) to estimate the activation of soil liquefaction under seismic condition. The database is collected from the published literature, including 270 liquefaction cases and 216 nonliquefaction case histories under different geological conditions and earthquakes used for construction and confirming the model. The model is built and optimized for hyperparameters based on a technique known as random search (RS). Then, the L2 regularization technique is used to solve the overfitting problem of the model. The analysis results are compared with a series of empirical formulas as well as some popular machine learning (ML) models. The results show that the RS-L2-FNN model successfully predicts soil liquefaction with an accuracy of 90.33% on the entire dataset and an average accuracy of 88.4% after 300 simulations which takes into account the random split of the datasets. Compared with the empirical formulas as well as other machine learning models, the RS-L2-FNN model shows superior performance and solves the overfitting problem of the model. In addition, the global sensitivity analysis technique is used to detect the most important input characteristics affecting the activation prediction of liquefied soils. The results show that the corrected SPT resistance (N1)60 is the most important input variable, affecting the determination of the liquefaction capacity of the soil. This study provides a powerful tool that allows rapid and accurate prediction of liquefaction based on several basic soil properties.
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Monde, A., B. E. Somba e A. Rahman. "The condition of chemical properties in the soil on the liquefied land in Jono Oge Village, Sigi Regency, Central Sulawesi". IOP Conference Series: Earth and Environmental Science 1253, n. 1 (1 ottobre 2023): 012112. http://dx.doi.org/10.1088/1755-1315/1253/1/012112.
Testo completoAbstract (sommario):
Abstract Liquefaction is an event in which the soil loses shear strength due to increased pore water stress by the presence of cyclic loading. As a result of this incident, a number of paddy fields and housing estates in Jono Oge village experienced liquefaction. There is mud vomiting and the movement of a number of soils, causing eroded areas and some of them experiencing hoarding Research aims to identify the chemical properties of soils affected by liquefaction. The study was conducted using the survey method, soil sampling was carried out by purposive sampling. Soil samples were taken on three categories of affected land: eroded land, landfilled land, and surrounding land that was not liquefied. The results showed that the areas affected by liquefaction in the three categories of land had a soil pH relative to the same criteria, namely neutral (pH 6.52-6.77). Then C-organic levels in both eroded and hoarding fields are moderate status (2.50-2.70%) and in non-liquefied lands is low status (1.52%), while N-Total all three have low status (0.12-0.19%). Sodium content is generally medium status (0.41-0.60 me/100g), Calcium is generally high status (11.88-13.42 me/100g) and Magnesium is generally moderately. This research was conducted after more than 2 years of liquefaction and the most affected soil chemical properties in the respected area is the increasing of C-organic content.
36
SHE, Dongcheng, e Quangxiang JIANG. "Study on Sand Liquefaction in the Anning River Area of Youjun Town". Chinese Earth Sciences Review 2, n. 1 (28 marzo 2023): 1–7. http://dx.doi.org/10.48014/cesr.20230310001.
Testo completoAbstract (sommario):
In order to find out the structural characteristics of the substance of the Quaternary, the liquefaction grade of sandy soil, the distribution of sandy soil liquefaction and the influence on the buildings and fields in the liquefaction area in the Anning River valley within the map area of Youjun Town, the liquefaction of sandy soil and pulverized soil layers distributed in the Anning River Valley is judged according to the requirements of relevant specifications. The main research means include collecting relevant engineering data in the region, arranging exploration holes on both sides of the river valley, hydrogeological investigation, etc. , obtaining the regional distribution and grade of sand and soil liquefaction through in-situ tests, indoor experiments and analysis, and drawing the sandy soil liquefaction contour sheet. The results show that the distribution of surface sandy soil in the region is mostly lenticular and interbedded, most of the sandy soil is buried deeper than 10m, and the distribution of sandy soil layers is regional from north to south. It is also ascertained that there is less sandy soil on the north side and no sandy soil layer in most of the area, the distribution of sandy soil layer on the south side is obviously concentrated, most of them are buried deeper; and the liquefaction area and the area with serious liquefaction grade are mainly concentrated in the southern part of the river valley (Yangjiaheba-Lisuo area) , which is oval-shaped and distributed along the Anning River Valley, while the liquefaction grade in the rest of the area is in the range from slight to moderate. The study of sand and soil liquefaction in this area will provide the theoretical basis for the subsequent engineering construction planning in this area.
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Fauzan, Nadia Milla Hanifah, Willy Peratundhika E, Mutia Putri Monika e Zev Al Jauhari. "Structural evaluation of 3-story dormitory reinforced concrete building considering soil liquefaction potential". E3S Web of Conferences 156 (2020): 05015. http://dx.doi.org/10.1051/e3sconf/202015605015.
Testo completoAbstract (sommario):
The liquefaction phenomenon is the increase in water pressure in the soil, which will reduce the soil strength in supporting the load and loss of binding power between its grains. Soil liquefaction usually occurs when there is a seismic movement in the soil layer due to seismic (earthquakes) loads. Therefore, the building constructed in the soil liquefaction prone area should be designed according to the standard code. However, many design consultants do not pay attention to this condition and the building still was designed as usual even the building is located on soil liquefaction prone area. In 2018, a 3-story dormitory building structure of Hamka’s boarding school was constructed on soil liquefaction prone area in Padang city. After reviewing the design document, it was found that the consultant did not consider the soil liquefaction in its structural analysis. In this study, an evaluation of the building structure was carried out to investigate the capacity of the building in resisting the loads. From the soil evaluation using the soil Cone Penetration Test (CPT) result, it was found that the location of the dormitory building has a liquefaction potential at a depth of 1.2 - 8 meters. Considering the soil liquefaction potential in the building, the structural analysis results show that the capacity of the dormitory building, especially column, beam and foundation were not strong enough to resist the combination loads acting on the structures. Therefore, the building structure should be strengthened to face the further big earthquake that will cause the soil liquefaction.
38
Ozcelik, Mehmet. "The Effects of Vertical Stress on the Liquefaction Potential Originated from Buildings in The Urban Areas". International Journal of Geotechnical Earthquake Engineering 8, n. 1 (gennaio 2017): 38–57. http://dx.doi.org/10.4018/ijgee.2017010103.
Testo completoAbstract (sommario):
Main purpose of this paper is to study the influence of vertical stress on soil liquefaction in urban areas. The literature provides limited information on vertical stress analysis of multiple footings, and, as a result, there is no accurate way to account for the effect of the foundation depth on liquefaction. Additionally, practical methods do not exist for considering the interaction between the neighboring foundations vertical stress and seismic forces in the urban area. Vertical stress distribution was calculated in examining the soil liquefaction potential exhibited by building foundations as a case study. The vertical stresses were chosen randomly for some buildings with foundation depths of 3.00 m; 4.50 and 6.00 m at the Burkent site (Burdur-Turkey). The influence of 5-storey buildings on the liquefaction potential of sandy soils was evaluated in terms of the safety factor (FS) against liquefaction along soil profile depths for different earthquakes. Standard Penetration Test (SPT) results were used based on simplified empirical procedure.
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Shi, Ming, Lianjin Tao e Zhigang Wang. "Study on the Influence of Deep Soil Liquefaction on the Seismic Response of Subway Stations". Applied Sciences 14, n. 6 (9 marzo 2024): 2307. http://dx.doi.org/10.3390/app14062307.
Testo completoAbstract (sommario):
Subway systems are a crucial component of urban public transportation, especially in terms of safety during seismic events. Soil liquefaction triggered by earthquakes is one of the key factors that can lead to underground structural damage. This study investigates the impact of deep soil liquefaction on the response of subway station structures during seismic activity, aiming to provide evidence and suggestions for earthquake-resistant measures in underground constructions. The advanced finite element software PLAXIS was utilized for dynamic numerical simulations. Non-linear dynamic analysis methods were employed to construct models of subway stations and the surrounding soil layers, including soil–structure interactions. The UBC3D-PLM liquefaction constitutive model was applied to describe the liquefaction behavior of soil layers, while the HS constitutive model was used to depict the dynamic characteristics of non-liquefied soil layers. The study examined the influence of deep soil liquefaction on the dynamic response of subway station structures under different seismic waves. The findings indicate that deep soil liquefaction significantly increases the vertical displacement and acceleration responses of subway stations compared to non-liquefied conditions. The liquefaction behavior of deep soil layers leads to increased horizontal effective stress on both sides of the structure, thereby increasing the horizontal deformation of the structure and posing a potential threat to the safety and functionality of subway stations. This research employed detailed numerical simulation methods, incorporating the non-linear characteristics of deep soil layer liquefaction, providing an analytical framework based on regulatory standards for evaluating the impact of deep soil liquefaction on the seismic responses of subway stations. Compared to traditional studies, this paper significantly enhances simulation precision and practical applicability. Results from this research indicate that deep soil layer liquefaction poses a non-negligible risk to the structural safety of subway stations during earthquakes. Therefore, the issue of deep soil liquefaction should receive increased attention in engineering design and construction, with effective prevention and mitigation measures being implemented.
40
Kuo, Yu-Shu, Kai-Jun Chong, Shang-Chun Chang, Juin-Fu Chai e Hui-Ting Hsu. "A Hybrid Method to Evaluate Soil Liquefaction Potential of Seabed at Offshore Wind Farm in Taiwan". Energies 14, n. 7 (26 marzo 2021): 1853. http://dx.doi.org/10.3390/en14071853.
Testo completoAbstract (sommario):
This paper undertakes liquefaction analysis with simplified procedures with standard penetration test (SPT) data and cone penetration test (CPT) data obtained from an offshore wind farm in the Changhua area. The soil liquefaction resistance calculated by the SPT-based simplified procedure suggested by the Japan Railway Association was in agreement with the laboratory results. The CPT is widely used in the site investigation of offshore wind farms. However, Taiwan’s registered professional engineers are still familiar with soil liquefaction analysis for offshore wind farms using SPT-based methods. Hence, a hybrid method that incorporates an SPT–CPT correlation into the New Japan Road Association (NJRA) method is proposed to evaluate the soil liquefaction potential for offshore wind farms in Taiwan. In the case studies of soil liquefaction with five groups of adjacent boreholes in Changhua’s offshore wind farms, the hybrid method shows that the soil liquefaction potential with CPT data is consistent with the results calculated with SPT-based simplified procedures. To quantify the risk of soil liquefaction, Monte Carlo simulation is used to calculate the uncertainty of CPT–qc for estimating the probability of soil liquefaction with the hybrid method.
41
Zhang, Yubin. "Risk analysis of soil liquefaction in earthquake disasters". E3S Web of Conferences 118 (2019): 03037. http://dx.doi.org/10.1051/e3sconf/201911803037.
Testo completoAbstract (sommario):
China is an earthquake-prone country. With the development of urbanization in China, the effect of population aggregation becomes more and more obvious, and the Casualty Risk of earthquake disasters also increases. Combining with the characteristics of earthquake liquefaction, this paper analyses the disaster situation of soil liquefaction caused by earthquake in Indonesia. The internal influencing factors of soil liquefaction and the external dynamic factors caused by earthquake are summarized, and then the evaluation factors of seismic liquefaction are summarized. The earthquake liquefaction risk is indexed to facilitate trend analysis. The index of earthquake liquefaction risk is more conducive to the disaster trend analysis of soil liquefaction risk areas, which is of great significance for earthquake disaster rescue.
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Alva Hurtado, Jorge Elias Domingo, e Carmen Eleana Ortiz Salas. "Updating the Occurrence of the Soil Liquefaction Phenomenon in Peru". TECNIA 30, n. 2 (26 novembre 2020): 6–17. http://dx.doi.org/10.21754/tecnia.v30i2.756.
Testo completoAbstract (sommario):
We present the information available on the phenomenon of soil liquefaction in Peru due to the seismic action and its representation in a map of soil liquefaction areas. The map of soil liquefaction areas is drawn to the scale 1: 5'000,000 and presents distinctions between liquefaction and probable liquefaction cases, according to the interpretation of the information available in the literature. All the documentation that presents evidence of the phenomenon of liquefaction, such as the formation of small volcanoes of mud and sand, the violent expulsion of water from the soil, the presence of intense cracking and the differential settlements due to the seismic action, has been detailed in this article.
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Rakhman, Heryawan Kurnia, Sito Ismanti e Trias Aditya. "Liquefaction potential analysis based on standard penetration test in coastal area (Case study: Loh Buaya, Rinca Island, Indonesia)". IOP Conference Series: Earth and Environmental Science 1314, n. 1 (1 marzo 2024): 012123. http://dx.doi.org/10.1088/1755-1315/1314/1/012123.
Testo completoAbstract (sommario):
Abstract An area has liquefaction potential when it has a shallow groundwater level, loose sandy soil, and is prone to earthquakes. There are several areas with such criteria that have not been analysed for liquefaction potential. This study aims to analyse and plot the liquefaction potential in the coastal area of Loh Buaya, Rinca Island, East Nusa Tenggara Province. Soil investigation data, such as SPT, sieve analysis, and groundwater level, as well as earthquake history that occurred from 1922-2022, served as the main data for liquefaction potential analyses. The methods used were Ground Motion Equation Prediction (GMPE) to calculate Peak Ground Acceleration (PGA), Simplified Procedure, and Liquefaction Severity Index (LSI) to make a liquefaction hazard assessment. LSI scores were used to provide micro-zonation of liquefaction potential with Inverse Distance Weighted (IDW) interpolation in QGIS. The result obtained is very dense gravel has no liquefaction potential whereas loose sandy soil has very high in LSI classification because loose sandy soil has liquefaction potential up to 20 meters of depth. The applying of micro-zonation LSI by IDW interpolation method can estimate the potential level of liquefaction hazard on Loh Buaya, Rinca Island with limited soil investigation data.
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Ajamnorouzi, M., e E. S. Hosseininia. "The impact of initial fabric anisotropy on cyclic liquefaction behavior with polygonal particles using the discrete element method (DEM)". IOP Conference Series: Earth and Environmental Science 1330, n. 1 (1 maggio 2024): 012020. http://dx.doi.org/10.1088/1755-1315/1330/1/012020.
Testo completoAbstract (sommario):
Abstract Liquefaction is one of the most significant phenomena that can occur in soil during an earthquake. The destructive effects of this phenomenon on earth structures have captured the attention of many geotechnical engineers. Additionally, the gradual increase in pore water pressure during the cyclic loading induced by the propagation of earthquake waves, known as cyclic liquefaction, is a crucial factor that might lead to the complete loss of shear strength in soils. A better understanding of cyclic liquefaction is essential for improving earthquake hazard analysis and mitigating structural damage. Factors influencing liquefaction behavior include particle size, particle grading, and soil fabric. By “soil fabric,” we refer to the arrangement and positioning of particles with each other, particle shape, and the shape of voids among particles. This research aims to focus on the effects of fabric anisotropy on cyclic liquefaction of granular soils with angular particles. To carry out this investigation, the discrete element method has been employed. In the discrete element method, the geometry of particles and, generally, the soil fabric can be considered. In this research, specimens with varying particle orientation angles were produced and subjected to cyclic loading tests under undrained conditions. By examining the stress paths of specimens during cyclic loading, it is observed that the initial fabric and inherent anisotropy significantly influence the behavior of the specimens. Inherent anisotropy leads to varying numbers of cycles required for the initial liquefaction of each specimen. Furthermore, it is observed that as the particle orientation angle increases, the localization of axial strains shifts from tensile to compressive directions. The effect of inherent anisotropy plays a substantial role in the initial liquefaction (ru = 1). If the liquefaction of specimens is of interest at lower values of ru, the effect of inherent anisotropy can be disregarded.
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Tsai, Y. T., e W. G. McDougal. "Random Wave-Induced Pore Pressure Accumulation in Marine Soils". Journal of Offshore Mechanics and Arctic Engineering 112, n. 4 (1 novembre 1990): 285–89. http://dx.doi.org/10.1115/1.2919868.
Testo completoAbstract (sommario):
Random wave-induced pore pressure is examined using linear superposition, Miner’s method and a single representative wave. Solutions are developed for deep and shallow soils. A deep soil has a higher liquefaction potential than a shallow soil for the same wave conditions. Linear superposition, Miner’s method and using the rms wave height are in general agreement for the deep soil. The significant wave overestimates the liquefaction potential and should not be used. There was poor agreement among the methods for a shallow soil.
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Liu, Fu Sheng, e Han Bing Bian. "Influence of Soil Saturation on the Free Field Response of Liquefiable Soils". Advanced Materials Research 378-379 (ottobre 2011): 237–40. http://dx.doi.org/10.4028/www.scientific.net/amr.378-379.237.
Testo completoAbstract (sommario):
Free field response of partially saturated sands to cyclic loading, with a particular attention to soil liquefaction has been studied. The study has been conducted using a numerical model elaborated for the liquefaction of partially saturated soils together with a cyclic elastoplastic constitutive relation implemented in a finite element program. The numerical model and the analysis of the influence of soil saturation on the free field response, for different positions of the water table have been investigated respectively. The result shows that the soil saturation degree largely affects the free field response to cyclic loading, with a decrease in soil saturation leading to a decrease in the rate of generation of excess pore-water pressure, and consequently to a reduction in the liquefaction risk.
47
Chou, Jui-Ching, Hsueh-Tusng Yang e Der-Guey Lin. "Calibration of Finn Model and UBCSAND Model for Simplified Liquefaction Analysis Procedures". Applied Sciences 11, n. 11 (7 giugno 2021): 5283. http://dx.doi.org/10.3390/app11115283.
Testo completoAbstract (sommario):
Soil-liquefaction-related hazards can damage structures or lead to an extensive loss of life and property. Therefore, the stability and safety of structures against soil liquefaction are essential for evaluation in earthquake design. In practice, the simplified liquefaction analysis procedure associated with numerical simulation analysis is the most used approach for evaluating the behavior of structures or the effectiveness of mitigation plans. First, the occurrence of soil liquefaction is evaluated using the simplified procedure. If soil liquefaction occurs, the resulting structural damage or the following mitigation plan is evaluated using the numerical simulation analysis. Rational and comparable evaluation results between the simplified liquefaction analysis procedure and the numerical simulation analysis are achieved by ensuring that the liquefaction constitutive model used in the numerical simulation has a consistent liquefaction resistance with the simplified liquefaction analysis procedure. In this study, two frequently used liquefaction constitutive models (Finn model and UBCSAND model) were calibrated by fitting the liquefaction triggering curves of most used simplified liquefaction analysis procedures (NCEER, HBF, JRA96, and T-Y procedures) in Taiwan via FLAC program. In addition, the responses of two calibrated models were compared and discussed to provide guidelines for selecting an appropriate liquefaction constitutive model in future projects.
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Pillai, V. S., e R. A. Stewart. "Evaluation of liquefaction potential of foundation soils at Duncan Dam". Canadian Geotechnical Journal 31, n. 6 (1 dicembre 1994): 951–66. http://dx.doi.org/10.1139/t94-110.
Testo completoAbstract (sommario):
A comprehensive program of field, laboratory, and analytical investigations was carried out to evaluate the potential of liquefaction for the foundation soils at Duncan Dam. Duncan Dam was completed in 1967 under the Columbia River Treaty in southeastern British Columbia. The 39 m high zoned embankment dam is founded on a sequence of sands, silts, and gravels. Some of the foundation soils may liquefy during earthquake loading and this would affect the stability and performance of the dam. The liquefaction studies were carried out in two phases to characterize the engineering properties of the foundation soils and to assess its potential for triggering liquefaction using the total stress approach. This paper describes methods of assessment of liquefaction potential using soil parameters based on field penetration data (Seed's method) and laboratory testing of undisturbed soil samples obtained in situ after freezing the ground (Lab method) and presents the results of triggering analysis. Influence of confining stress (Kσ) and initial static shear stress (Kα) on liquefaction were investigated and site-specific Kσ and Kα curves were developed.For the design earthquake (M 6.5, PGA = 0.12g) both the Lab method and Seed's method predict a significant extent of liquefaction of the foundation soils under the downstream slope in the right half of the dam. Key words : sand, liquefaction, confining stress, density, cyclic resistance ratio.
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Rani, Ch Sandhya, T. S. Ram Babu e Jahnavi Donavalli. "Analysis of Liquefaction Potential of Soils in Guntur Region (CRDA)". IOP Conference Series: Earth and Environmental Science 1130, n. 1 (1 gennaio 2023): 012037. http://dx.doi.org/10.1088/1755-1315/1130/1/012037.
Testo completoAbstract (sommario):
Abstract In earthquake-prone areas that are susceptible, liquefaction is a severe natural hazard. Due to a rise in pore water pressure, soil liquefaction happens Due to the reduction in strength and stiffness of saturated and cohesion-less soil. By being rapidly loaded or shaken during an earthquake, soil can occasionally lose part of its strength. Liquefaction results in soil failures, which severely harm buildings supported on such grounds and incur large economic losses. Regarding the protection of both life and property, study of liquefaction potential is crucial. The aim of the study is to assess the liquefaction potential in the Guntur region. Understanding the liquefaction mechanism is necessary for a methodical approach to the improvement of capacities to evaluate the liquefaction potentiality of soil deposits & earth structures. So, utilizing the information from the (SPT), liquefaction analysis is done utilizing the strategy of the simplified approach described by Seed and Idriss. It is possible to determine a number of parameters, including reduction factor, cyclic stress ratio (CSR), cyclic resistance ratio (CRR), and liquefaction potential index. More detailed studies can be done by using software to acquire more accuracy.
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Vongchavalitkul, Sanguan. "Probabilistic Safety Factor of Soil Liquefaction". Applied Mechanics and Materials 217-219 (novembre 2012): 2414–18. http://dx.doi.org/10.4028/www.scientific.net/amm.217-219.2414.
Testo completoAbstract (sommario):
The most widely used method of liquefaction prediction are perform in deterministic process. The deterministic method according to seismic Chinese code is introduced by Z. CAO et al (2008). The deterministic method used the standard penetration test (SPT) to evaluate the liquefaction of soil. With this method, liquefaction of soil is predicted to occur if the factor of safety(FS), which in the ratio of critical SPT-N value(Resistance) over the actual measurement SPT-N(Load), is less than or equal to one. If the factor of safety greater than one, no soil liquefaction is predicted. Because the significant uncertainties in variable involved in the deterministic factor of safety, the probability method need to use. because the significant uncertainties in the random variables involved, the probabilistic method is needed to predict liquefaction. Probability of failure may be performed in which the liquefaction potential is assessed in term of probability safety factor (central safety factor). The study case is shown that the probabilistic method given the much more information for engineering decision than the deterministic method that given only the safety factor..