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Adaptive sampling strategy for characterizing spatial distribution of soil liquefaction potential using cone penetration test

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Journal of Rock Mechanics and Geotechnical Engineering 2022年第4期14卷 1221-1231页

作者： Zheng Guan Yu Wang Tengyuan Zhao Department of Architecture and Civil Engineering City University of Hong KongTat Chee AvenueKowloonHong KongChina School of Human Settlements and Civil Engineering Xi’an Jiaotong UniversityXi’an710049China

Characterizing spatial distribution of soil liquefaction potential is critical for assessing liquefactionrelated hazards(*** damages caused by liquefaction-induced differential settlement).However,in engineering practice,soil liquefaction potential is usually measured at limited locations in a specific site using in situ tests,*** penetration tests(CPTs),due to the restrictions of time,cost and access to subsurface *** these cases,liquefaction potential of soil at untested locations requires to be interpreted from limited measured data points using proper interpolation method,leading to remarkable statistical uncertainty in liquefaction *** underlines an important question of how to optimize the locations of CPT soundings and determine the minimum number of CPTs for achieving a target reliability level of liquefaction *** tackle this issue,this study proposes a smart sampling strategy for determining the minimum number of CPTs and their optimal locations in a selfadaptive and data-driven *** proposed sampling strategy leverages on information entropy and Bayesian compressive sampling(BCS).Both simulated and real CPT data are used to demonstrate the proposed *** examples indicate that the proposed method can adaptively and sequentially select the required number and optimal locations of CPTs.

关键词： liquefaction potential Information entropy Cone penetration test(CPT) Site characterization Compressive sampling

Application of machine learning to the Vs-based soil liquefaction potential assessment

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Journal of Mountain Science 2023年第8期20卷 2197-2213页

作者： SUI Qi-ru CHEN Qin-huang WANG Dan-dan TAO Zhi-gang State Key Laboratory for GeoMechanics and Deep Underground Engineering China University of Mining and Technology(Beijing)Beijing 100083China School of Mechanics and Civil Engineering China University of Mining and Technology(Beijing)Beijing 100083China

Earthquakes can cause violent liquefaction of the soil, resulting in unstable foundations that can cause serious damage to facilities such as buildings, roads, and dikes. This is a primary cause of major earthquake disasters. Therefore, the discrimination and prediction of earthquake-induced soil liquefaction has been a hot issue in geohazard research. The soil liquefaction assessment is an integral part of engineering practice. This paper evaluated a dataset of 435 seismic sand liquefaction events using machine learning algorithms. The dataset was analyzed using seven potential assessment parameters. Ten machine learning algorithms are evaluated for their ability to assess seismic sand liquefaction potential, including Linear Discriminant Analysis(LDA), Quadratic Discriminant Analysis(QDA), Naive Bayes(NB), KNearest Neighbor(KNN), Artificial Neural Network(ANN), Classification Tree(CT), Support Vector Machine(SVM), Random Forest(RF), e Xtreme Gradient Boosting(XGBoost), Light Gradient Boosting Machine(Light GBM). A 10-fold cross-validation(CV) method was used in the modeling process to verify the predictive performance of the machine learning models. The final percentages of significant parameters that influenced the prediction results were obtained as Cyclic Stress Ratio(CSR) and Shear-Wave Velocity( VS1) with 56% and 38%, respectively. The final machine learning algorithms identified as suitable for seismic sand liquefaction assessment were the CT, RF, XGBoost algorithms, with the RF algorithm performing best.

关键词： Seismic soil liquefaction Machine learning Assessment liquefaction potential shear wave velocity

Dynamic characterization of tailing dam using fully coupled dynamic analysis with different boundary conditions-a case study

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Earthquake Engineering and Engineering Vibration 2023年第4期22卷 995-1013页

作者： Thanikella Vijayasri Department of Civil Engineering Indian Institute of ScienceBangaloreKarnataka 560012India

The seismic response analysis of a tailing dam is studied using a fully coupled effective stress approach in conjunction with an advanced multi yield surface plastic constitutive model for tailing *** controlled static and cyclic triaxial tests were carried out to obtain the constitutive model for the tailing *** tailing materials were collected from the Rampura Agucha tailing dam(Rajasthan State,India).A 2D nonlinear finite element(FE)model was then developed using different boundary conditions from the tailing embankment constructed using the downstream and upstream method of rising using OpenSees *** first case,the model boundary was fixed in both the X and Y directions,and in the second case,viscous dashpots were introduced for both side and horizontal *** model was validated with experimental results on tailing *** were carried out considering five different earthquake motions,which were applied at the *** of the different boundary conditions in terms of displacement flow vectors,pore pressure and stress-strain curves during shaking are *** the analysis,it was observed that the viscous boundary condition replicates the actual field conditions more accurately than the fixed boundary *** addition,it was found that the tailing embankment constructed by the downstream and upstream method of rising is not susceptible to liquefaction and lateral spreading for earthquake motions,even for a magnitude>5.5.

关键词： tailing embankment cyclic triaxial test seismic analysis liquefaction potential transmitting and fixed boundary conditions

Dynamic properties and liquefaction behaviour of cohesive soil in northeast India under staged cyclic loading

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Journal of Rock Mechanics and Geotechnical Engineering 2018年第5期10卷 958-967页

作者： Shiv Shankar Kumar A.Murali Krishna Arindam Dey Department of Civil Engineering Indian Institute of Technology Guwahati

Estimation of strain-dependent dynamic soil properties, e.g. the shear modulus and damping ratio, along with the liquefaction potential parameters, is extremely important for the assessment and analysis of almost all geotechnical problems involving dynamic loading. This paper presents the dynamic properties and liquefaction behaviour of cohesive soil subjected to staged cyclic loading, which may be caused by main shocks of earthquakes preceded or followed by minor foreshocks or aftershocks, respectively. Cyclic triaxial tests were conducted on the specimens prepared at different dry densities （1.5 g/cm3 and 1.75 g/cm3） and different water contents ranging from 8% to 25%. The results indicated that the shear modulus reduction （G/Gmax） and damping ratio of the specimen remain unaffected due to the changes in the initial dry density and water content. Damping ratio is significantly affected by confining pressure, whereas G/Gmax is affected marginally. It was seen that the liquefaction criterion of cohesive soils based on single-amplitude shear strain （3.75% or the strain at which excess pore water pressure ratio becomes equal to 1, whichever is lower） depends on the initial state of soils and applied stresses. The dynamic model of the regional soil, obtained as an outcome of the cyclic triaxial tests, can be successfully used for ground response analysis of the region.

关键词： Cohesive soil Dynamic soil properties liquefaction potential Cyclic triaxial tests Staged cyclic loading

liquefaction Assessment in Golem Area, Albania, by Means of In-situ Tests

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Journal of Civil Engineering and Architecture 2015年第5期9卷 547-553页

作者： Shpresa Gashi Neritan Shkodrani Department of Civil Engineering Faculty of Civil Engineering Polytechnic of Tirana Tiran 1000 Albania

The liquefaction is a very significant phenomenon in clayey silty soils, silty sands and also sands. The high potential of liquefaction is generally recognized when these types of soils are laid under the hydrostatic water table. Low plasticity silts, silty sands and sands are found as recent alluvial deposits in the western coastal part of Albania, especially in the sandy beaches of Adriatic Sea near Durres City. The aim of this study is to evaluate the soil liquefaction potential in the area of Golem. Ten CPTUs （cone penetration test with pore pressure measurements） are carried out for the site investigation of soils. In this paper, results of the CPTU based liquefaction analysis are presented. The data of two CPTUs （10 in total） are analyzed and factor of safety was found by considering different levels of hazard and ground water. The results of liquefaction potential analysis show that the soils in the area of Golem have a high risk of liquefaction.

关键词： Cone penetration test liquefaction potential cyclic resistance ratio cyclic stress ratio safety factor.