Liquefaction-induced Lateral Displacements Research Articles

Fluvial geomorphic factors affecting liquefaction-induced lateral spreading

Liquefaction-induced lateral displacements represent a major geohazard in earthquake-prone regions, yet the uncertainty associated with their prediction remains notoriously high. Documented observations after recent earthquakes provide evidence that depositional environment-specific geologic conditions play a crucial role in liquefaction susceptibility, and in the severity and spatial extent of liquefaction-induced ground deformations. However, this evidence is largely qualitative in nature, which limits the potential to incorporate the effects of depositional processes and environments in the next generation of lateral spreading predictive models. This study provides a framework to quantitatively assess the relationship between depositional environment-specific geologic factors and lateral spreading by means of simple fluvial geomorphic facies models, geotechnical engineering data (e.g. Cone Penetration Test data), and geospatial analytics. Three hypotheses are introduced and tested using lateral spreading ground deformations observed following the 2011 Christchurch earthquake along the Avon and Heathcote rivers in New Zealand. The results from this study indicate that the presence of an active (i.e. with active sediment deposition) compared to inactive (e.g. abandoned) channels is the most important fluvial geomorphologic variable out of the three tested. The other two are associated with the location relative to the meander bend position, including location within the point bar (inside) or the cut bank (outside), and upstream versus downstream within a given point bar. Findings from this study show that more lateral spreading occurs within point bars, and upstream (within a given point bar) in simple meander bends. However, the presence of geomorphic complexities (e.g. cut banks connected to an incised channel or tributary and/or channel confinement) can challenge the unbiased quantification of the contribution of a single geomorphic variable to the observed lateral displacements. These findings can be applied to other fluvial environments outside of New Zealand, and the proposed framework can be implemented for other non-fluvial depositional settings.

Liquefaction-Induced Lateral Displacement and Settlement Mapping for Yogyakarta-Bawen Toll Road Section I & II, Indonesia

The liquefaction-induced ground displacement (the lateral displacement and ground settlement) study in the Yogyakarta-Bawen toll road, Indonesia, is not yet conducted as the importance of this project, the project needs to be mapped. In this study, the mapping is conducted using two methods for lateral displacement, Gillins & Bartlett’s method and Zhang et al.’s method, while the mapping of ground settlement using Tokimatsu & Seed’s method and Yoshimine’s method. For Gillins & Bartlett’s method, the lateral displacement map in Yogyakarta-Bawen is dominated by moderate to high categories in section I but relatively low in section II. Meanwhile, Zhang et al.’s map in the I & II sections of the toll road is relatively dominated by the moderate category. Furthermore, the ground settlement map in I & II sections with Tokimatsu & Seed is mostly categorized as very high meanwhile Yoshimine’s map is predominately classified as low to moderate.

Response of soil–pile–superstructure–quay wall system to lateral displacement under horizontal and vertical earthquake excitations

The excess pore water pressure generated under the combined vertical and horizontal earthquake excitations is generally greater than that under the unidirectional excitation, which may further affect the dynamic response of soil-pile-superstructure-quay wall (SPSQ) system. This study conducted a coupled effective-stress analysis for the response of SPSQ system to liquefaction-induced lateral displacement under horizontal and vertical earthquake excitations. To accurately describe the lateral displacement behind the quay wall, the liquefaction behavior of soils was described by a modified generalized plasticity model with parameters properly determined from laboratory tests. The numerical model of the SPSQ system was validated against the previously reported centrifuge model tests. The results show that the earthquake excitation with abundant low-frequency component causes greater residual lateral displacements of pile cap (ux,RC) and quay wall (ux,RQ) than that with abundant high-frequency component. The ux,RC and ux,RQ tend to increase as the peak vertical acceleration increases for both vertical and inclined piles. Increasing the fixity of the quay wall significantly reduces the influence of vertical ground motion on the ux,RC and ux,RQ. The polarity reversal of the vertical ground motion also has a significant effect on the ux,RC and ux,RQ and should be considered in the analyses. In addition, the lateral displacement of liquefied ground causes an amount of rotation of the cap of the inclined pile, probably leading to the potential shear failure at the head of piles. Special consideration should be given to the earthquake-induced shear force at deeper location because the shear force could be significantly greater than that at the head of both inclined and vertical piles in certain cases.

Assessment of liquefaction-induced lateral spread using soft computing approaches

Lateral spread is a common ground deformation induced by soil liquefaction, which has caused extensive damage to buildings and lifelines in past earthquakes. At present, several empirical methods for assessing lateral displacement have been proposed. Due to the complexity of the problem, it is difficult for traditional methods to predict the lateral spread displacement with high accuracy. In this study, a new database of 522 lateral spreading case histories was established based on the databases developed by Youd et al., Chu et al., and NGL (Next Generation Liquefaction). The confidence ellipse was used to evaluate the similarity between parameters of liquefiable soil layers for two site conditions (free face and gently sloping ground). Then, based on the new database, predictive models for assessing liquefaction-induced lateral displacement were developed by different soft computing approaches including Ridge Regression, Lasso & Lasso CV, Random Forest Regression (RF), eXtreme Gradient Boost (XGBoost), and Multivariate Adaptive Regression Splines (MARS). The MARS model showed good predictive performance (the R2 values were 0.583 and 0.555 on testing set, respectively) and can generate explicit expressions. The results of SHAP investigation showed that log(T15) is the most important feature variable in RF model, where T15 is the thickness of liquefiable soil layer. Further analysis showed that thicker liquefiable soil layers, smaller epicentral distances, larger magnitudes, and unfavorable topographical conditions will increase the possibility of lateral displacement, while larger grain sizes and more fines contents will reduce the probability of lateral displacement.

Identification of optimal ground-motion intensity measures for assessing liquefaction triggering and lateral displacement of liquefiable sloping grounds

This article aims at identifying the optimal scalar- and vector-valued intensity measures (IMs) for predicting liquefaction triggering and the consequence of liquefaction (i.e. permanent deformation of sloping grounds), respectively. A total of 169 ground motions were selected from the NGA-West2 database. Using the selected ground motions as input, one-dimensional dynamic analyses were conducted for generic sloping ground soil profiles consisting of a loose-sand liquefiable layer implemented in OpenSees. The excess pore water pressure ratio and the liquefaction-induced lateral displacement were regarded as the engineering demand parameters (EDPs) of interest. A total of 20 scalar-IMs and 21 vector-IMs representative of various characteristics of seismic loading were evaluated as candidate IMs. The criteria for identifying optimal IMs include consideration for the efficiency, sufficiency, and predictability of the given IMs. An error propagation approach was employed to evalute the overall uncertainty of EDPs under scenario earthquakes using different IMs as predictor variables. Based on the results of extensive comparative analyses, acceleration spectrum intensity (ASI), and the vector of peak ground acceleration and spectral acceleration at 0.3 s (peak ground acceleration (PGA) and Sa(0.3 s), respectively) are identified as the optimal scalar- and vector-IM for liquefaction triggering evaluation, respectively. However, Arias intensity ( Ia) and vectors of [ Ia, cumulative absolute velocity] and [PGA, Ia] are identified as the optimal scalar- and vector-IM for predicting the liquefaction-induced lateral displacements. The optimal IMs identified could be used in performance-based liquefaction hazard evaluations, to assess the liquefaction triggering and consequence of liquefiable sites.

Prediction of Liquefaction-Induced Lateral Displacements Using Gaussian Process Regression

During severe earthquakes, liquefaction-induced lateral displacement causes significant damage to designed structures. As a result, geotechnical specialists must accurately estimate lateral displacement in liquefaction-prone areas in order to ensure long-term development. This research proposes a Gaussian Process Regression (GPR) model based on 247 post liquefaction in-situ free face ground conditions case studies for analyzing liquefaction-induced lateral displacement. The performance of the GPR model is assessed using statistical parameters, including the coefficient of determination, coefficient of correlation, Nash–Sutcliffe efficiency coefficient, root mean square error (RMSE), and ratio of the RMSE to the standard deviation of measured data. The developed GPR model predictive ability is compared to that of three other known models—evolutionary polynomial regression, artificial neural network, and multi-layer regression available in the literature. The results show that the GPR model can accurately learn complicated nonlinear relationships between lateral displacement and its influencing factors. A sensitivity analysis is also presented in this study to assess the effects of input parameters on lateral displacement.

Seismic Responses of a Large Unequal-span Underground Subway Station in Liquefiable Soil Using Shaking Table Test

ABSTRACT Sand liquefaction is considered to be one of the main causes of severe earthquake damage. The seismic response of large-scale underground structures is mainly controlled by the deformation of surrounding soils, and the large liquefaction-induced lateral displacement poses a serious threat to large underground structures. In this paper, a large-scale shaking table test is performed to simulate the dynamic interaction between liquefiable foundation, diaphragm wall and underground subway station. The results indicate that the interaction mode between soil and underground structure changes significantly with the different liquefaction states of surrounding soil. The underground structure improves the liquefaction resistance of adjacent lateral soils, but significantly reduces the liquefaction resistance of soils located directly below the structure. The development of dynamic pore pressure is related to the seismic intensity, and a significant dissipation of dynamic pore pressure usually occurs after the end of a strong seismic excitation. Moreover, the acceleration response law along the vertical direction has changed significantly within the buried depth of the underground structure. Specifically, the acceleration response of the lateral foundation is inhibited in the absence of liquefaction, but is enhanced in the complete liquefaction. In addition, the liquefaction states of model site also affect the spatial strain response of the underground structure.

Evaluation of liquefaction-induced lateral displacement using Bayesian belief networks

Liquefaction-induced lateral displacement is responsible for considerable damage to engineered structures during major earthquakes. Therefore, an accurate estimation of lateral displacement in liquefaction-prone regions is an essential task for geotechnical experts for sustainable development. This paper presents a novel probabilistic framework for evaluating liquefaction-induced lateral displacement using the Bayesian belief network (BBN) approach based on an interpretive structural modeling technique. The BBN models are trained and tested using a wide-range case-history records database. The two BBN models are proposed to predict lateral displacements for free-face and sloping ground conditions. The predictive performance results of the proposed BBN models are compared with those of frequently used multiple linear regression and genetic programming models. The results reveal that the BBN models are able to learn complex relationships between lateral displacement and its influencing factors as cause-effect relationships, with reasonable precision. This study also presents a sensitivity analysis to evaluate the impacts of input factors on the lateral displacement.

A multilateral analysis of slope failure due to liquefaction-induced lateral deformation using shaking table tests

Liquefaction-induced lateral displacement can cause substantial deformations and trigger failure in the saturated sandy slopes. This study elaborates on the results of a shaking table experiment performed on a saturated sandy slope model. A transparent Plexiglass container was used to allow visualization of the time-dependent ground displacements at different grid points. Using colored sand grid along with the video-tracking analysis technique provided an excellent opportunity for instant monitoring of the model deformation in both the time and space domains. Furthermore, the pore pressure buildup and dissipation in the soil medium and acceleration time histories of the model were recorded and analyzed. Detailed and comprehensive analyses of the high-resolution recorded data streams resulted in the determination of the onset of liquefaction and the induced subsidence, acceleration response, deformation behavior, and shear strain progress through time and depth at different slope sections. It was also found that the shear strain rate was different in the on-slope and free field locations, and its value was proportional to the liquefaction duration. It was also observed that the variation of the shear strain rate at different depths in the free field led to a localized sliding event.

Evaluation of liquefaction-induced lateral displacement using a GMDH-type neural network optimized by genetic algorithm

Liquefaction-induced lateral spreading is known to be a significant type of damage for engineering structures. This research introduces an evolutionary algorithm by using a combination of the group method of data handling (GMDH)–type neural network and genetic algorithm for predicting liquefaction-induced lateral displacements. A new and comprehensive database containing 526 case histories from 18 significant earthquakes is compiled and analyzed to develop a new predictive model. Also, the developed equation evaluated the results of previously published experimental studies and showed an acceptable performance. The obtained results show a more accurate performance of the proposed model compared with previous models. Since the presented model has been developed based on numerous seismic events and site conditions, it is more general and reliable than other models.

Pile group response to liquefaction-induced lateral spreading: E-Defense large shake table test

This paper presents the results of a large-scale shake table test at E-Defense facility on a pile group located adjacent to a gravity-type quay wall and were subjected to liquefaction-induced large ground displacements. Extensive liquefaction-induced large ground lateral spreading displaced the quay wall about 2.2m and damaged the pile foundation. The pile foundation consisted of a six-pile group which supported a footing and a superstructure model. Large lateral soil displacements were measured by several sensors such as inclinometers and the results favorably agreed with the directly observed deformations. Soil lateral displacement decreased as the distance from the quay wall increased landward. The piles were densely instrumented and the measured bending strain records were able to explain the damage to the piles. Lateral pressures of the liquefied soil exerted on the piles were measured using earth pressure (EP) sensors. The application of two design guidelines (JRA [1] and JSWA [2]) for estimation of liquefaction-induced lateral pressure on piles is discussed and their advantages and shortcomings are addressed. Furthermore, two simplified methods (Shamoto et al. [3] and Valsamis et al. [4]) are employed to predict the extent of liquefaction-induced large ground displacements and they are compared to the measured deformations. Finally, their accuracy for predicting the liquefaction-induced lateral displacements is evaluated and practical recommendations are made.

Probabilistic Performance-Based Procedure to Evaluate Pile Foundations at Sites with Liquefaction-Induced Lateral Displacement

Liquefaction-induced ground deformation has caused major damage to bridge and wharf structures in past earthquakes. Large lateral ground displacements may induce significant forces in the foundation and superstructure, which may lead to severe damage or even collapse. A performance-based earthquake engineering (PBEE) approach can provide an objective assessment of the likely seismic performance, so that agencies can evaluate bridge or wharf structures, compare retrofit strategies, and rank them within their overall system. In this paper, a probabilistic PBEE design procedure that incorporates findings from recent research on this problem is presented. The proposed approach can provide answers in terms that are meaningful to owners, such as expected repair costs and downtimes. The methodology is validated through its application to a well-documented case history. Results show that the proposed approach provides a good estimate of the seismic performance of pile-supported structures at sites with liquefaction-induced lateral displacement.

A simplified numerical approach for lateral spreading evaluation

Los desarrollos ocurridos en las últimas décadas, tanto en los métodos numéricos de solución de problemas de ingeniería geo-sísmica, como licuación y sus efectos, así como en la tecnología computacional, ha permitido que el uso de técnicas rigurosas de modelado matemático sean más frecuentes en ingeniería aplicada. Sin embargo, para el caso particular de la estimación de desplazamientos laterales inducidos por sismos, (asociados a la licuación de áreas extensas de terreno), resulta complicado para llevar a cabo análisis detallados que involucren modelos bi y tridimensionales. Es común el recurrir a estimaciones estadísticas, o inclusive a predicciones obtenidas con sistemas neurodifusos. En este artículo, se introduce un enfoque simplificado para calcular los desplazamientos laterales inducidos por sismos cuando se presenta licuación. La respuesta dinámica de un perfil de suelo es simulada a través de elementos finitos unidimensionales acoplados a un esquema de generación de presiones de poro. La ecuación de movimiento se resuelve en el dominio del tiempo y con base en cada incremento de presión de poro. Los parámetros de resistencia y dinámicos del suelo se modifican, permitiendo la estimación de los desplazamientos del suelo que ocurren durante el evento dinámico. La formulación propuesta se aplica al análisis de varios casos de estudio en donde se realizaron mediciones de desplazamientos laterales.

Empirical models for estimating liquefaction-induced lateral spread displacement

Existing empirical models for estimating liquefaction-induced lateral spread displacement ( D LL) have been derived from a dataset poorly distributed with respect to earthquake magnitude and source distance, and also produced from different tectonic source types and faulting mechanisms. Both the poor distribution and mixed tectonic source types and faulting mechanisms of the data have an adverse impact on the reliability of the empirical models. To overcome these problems in the development of empirical models, we replace the direct use of magnitude and source distance with pseudo-displacement derived from spectral acceleration attenuation models that are well supported by earthquake data, and use a modification factor to account for effects of the non-linear soil response. Attenuation models derived from very large and reasonably well-balanced datasets have been selected, one being a Japanese attenuation model and other being a combination of the Sadigh et al. model and the Youngs et al. model. These models are capable of accounting for the effects of earthquake tectonic source type and faulting mechanism. We determined the model coefficients by selecting the pseudo-displacements calculated for a number of spectral periods to achieve an unbiased distribution of residuals with respect to earthquake magnitude and source distance. Sensitivity analyses have been carried out based on the new and existing models, and show that the new model is more robust than the existing models. Comparison with a limited number of data from the 1997 Kocaeli, Turkey earthquake suggests our model provides comparable liquefaction-induced lateral displacement D LL estimates.

Estimating Liquefaction-Induced Lateral Displacements Using the Standard Penetration Test or Cone Penetration Test

A semiempirical approach to estimate liquefaction-induced lateral displacements using standard penetration test (SPT) or cone penetration test (CPT) data is presented. The approach combines available SPT- and CPT-based methods to evaluate liquefaction potential with laboratory test results for clean sands to estimate the potential maximum cyclic shear strains for saturated sandy soils under seismic loading. A lateral displacement index is then introduced, which is obtained by integrating the maximum cyclic shear strains with depth. Empirical correlations from case history data are proposed between actual lateral displacement, the lateral displacement index, and geometric parameters characterizing ground geometry for gently sloping ground without a free face, level ground with a free face, and gently sloping ground with a free face. The proposed approach can be applied to obtain preliminary estimates of the magnitude of lateral displacements associated with a liquefaction-induced lateral spread.