The occurrence of settlements induced by soil liquefaction will exert a substantial influence on buildings situated in earthquake-prone regions. Previous studies integrated the viscous-damping force into the governing equation to characterize building settlements and considered the apparent viscosity as an important parameter. The existing equation can be utilized to predict the settlement magnitude in the final stage as well as its evolution. However, due to the insufficient description of apparent viscosity, it is commonly regarded as a constant during the process of evaluating settlement. When adopting this mechanism, the evolution of building settlement often proves inadequate in fully capturing actual conditions. The aim of this study is to propose a prediction model for estimating liquefaction-induced settlement of shallow-founded buildings, which is formulated by an analytically differential equation. The proposed model incorporates the time-dependent viscosity of liquefied soil and introduces the concept of a soil column submerged in liquefied soil during seismic shaking. The evolution of settlement and the final settlement magnitude induced by soil liquefaction is evaluated through the analytical estimation, and these findings are subsequently compared with the results obtained from centrifuge experiments and numerical simulations. Furthermore, the proposed model is employed to investigate the correlation between building settlement and the geometric characteristics of shallow foundations. The proposed methodology shows considerable promise as an intermediate tool for assessing building settlement, offering practical simplicity in real scenarios.

Drag embedded anchors (DEA) are widely used in offshore engineering. The anchor foundations are installed in the seabed through the drag force applied by the mooring line and provide holding capacity to marine structures. Offshore wind farms in Taiwan are located in active earthquake zones, where a considerable amount of sandy soil at the upper layer of seabed results in a high potential for soil liquefaction. Since DEA are a promising option for floating wind turbines, this study conducted a shaking table test on two 1/30-scale anchors in medium dense sand to investigate the dynamic behavior of DEA during earthquakes and after excess pore water pressure dissipation. The test results reveal no significant impact on the orientation of the anchors, which could be due to the uplift force from the excess pore water pressure acting on the fluke. After the excess pore water pressure dissipates, the soil density increases, and the fluke angle becomes favorable, thus increasing the anchor's holding capacity when subjected to additional drag.

Tabriz is located in one of the important seismic areas of the world and has witnessed severe earthquakes in the past centuries. Earthquake is associated with multiple risks including geotechnical risks which affected many cities around the world. One of these important risks is the phenomenon of soil liquefaction. Soil liquefaction is the reason for many damages caused by earthquakes which can cause lots of damage to vital arteries of cities, mines, pipe lines and the buried structures in the soil. One of the recent challenges in dealing with liquefaction is utilizing intelligent tools for predicting the effects of this phenomenon in soil layers. For this purpose, a total number of 100 soil samples are collected, while an empirical approach is also developed for achieving Liquefaction Potential Index (LPI) by means of the depth of the soil layers, SPT values, penetration indices, fines content percentages, ground acceleration, and water level of the soil samples. For prediction purpose, the recently developed configuration of the Gradient Boosting (GB) methods is utilized as the main approach while the Artificial Neural Network (ANN) and the Decision Tree (DT) approaches are utilized for comparative investigations. For validation process, 10% of the samples are utilized in a stochastic way to intelligently evaluate the capability of the GB method in contrast to the alternative approaches. The results demonstrate the capability of the GB approach in providing efficient predictive results in dealing with the LPI prediction problem. Regarding the training phase, GB provided the maximum absolute error of 3.44 x 10-8 while the DT's result is partially competitive with maximum absolute of 3.15. Based on the test phase, GB can provide the lowest Mean Squared Error (MSE) of 0.09 while the DT with 0.11 and ANN with 3.25 have the other ranks. The GB is capable of reaching to lowest Mean Absolute Percentage Error (MAPE) of 3.64 in this phase while the DT with 3.07 and DT and ANN with 4.97 and 26.05 have second and third ranks respectively. 0.98 with 2% inaccuracy rate.

The study area, located in Martil, northern Morocco, lies in a region with high seismic risk, near a subduction zone. As a result, loose soils, such as sands, lose their shear strength under seismic loads due to an increase in pore water pressure, leading to deformations. The objective of this study is to assess the risk of soil liquefaction at the site where the Lalla Khadija High School will be constructed. The method used to evaluate the liquefaction risk is based on in-situ test results, as proposed by Seed and Idriss (J Soil Mech Found Div 97(9):1249-1273, 1971. https://doi.org/10.1061/JSFEAQ.0000981). Specifically, the liquefaction potential is assessed using data from the cone penetration test (CPT). This methodological approach combines a qualitative evaluation of susceptibility, which identifies the presence of fill materials and Plio-Quaternary sands-potentially liquefiable materials. At this stage, a quantitative evaluation of susceptibility is performed by calculating the safety factor, defined as the ratio between the normalized cyclic resistance ratio of the soil and the normalized cyclic stress ratio induced by the earthquake. The results of the CPT indicate that the normalized penetration resistance (qc1Ncs) consistently exceeds 160, which reflects sufficient soil strength. Consequently, the analysis confirms the absence of liquefaction risk in the sandy layers between depths of 1.8 m and 14 m. Therefore, the studied site has no liquefaction potential. This study has certain limitations. It relies solely on the method of Seed and Idriss (1971) to assess liquefaction risk, thereby restricting comparisons with alternative approaches. Additionally, the analysis focuses exclusively on the Lalla Khadija High School site, preventing extrapolation to the entire Martil plain. Nevertheless, by confirming the absence of liquefaction risk at this site, the study enables optimized foundation design, ensuring the stability of the infrastructure in the event of an earthquake. This contributes to occupant safety and improved seismic risk management in the region.

Soil liquefaction is a major contributor to earthquake damage. Evaluating the potential for liquefaction by conventional experimental or empirical methods is both time-intensive and laborious. Utilizing a machine learning model capable of precisely forecasting liquefaction potential might diminish the time, effort, and expenses involved. This research introduces an innovative predictive model created in three phases. Initially, correlation analysis determines essential elements affecting liquefaction. Secondly, predictions are produced using Convolutional Neural Networks (CNN) and Deep Belief Networks (DBN), verified by K-fold cross-validation to guarantee resilience. Third, Ant Colony Optimization (ACO) improves outcomes by increasing convergence efficiency and circumventing local minima. The suggested EC + ACO model substantially surpassed leading approaches, such as SVM-GWO, RF-GWO, and Ensemble Classifier-GA, attaining a very low False Negative Rate (FNR) of 2.00 % when trained on 90 % of the data. A thorough performance evaluation shown that the model achieved a cost value of 1.133 % by the 40th iteration, exceeding the performance of other models such SVMGWO (1.412 %), RF-GWO (1.305 %), and Biogeography Optimized-Based ANFIS (1.7439 %). The model exhibited significant improvements in convergence behavior, with a steady decline in cost values, especially between the 20th and 50th iterations. Additional validation using empirical data from the Tohoku-oki, Great East Japan earthquake substantiated the EC + ACO model's enhanced accuracy and dependability in mirroring observed results. These findings underscore the model's resilience and efficacy, providing a dependable method for forecasting soil liquefaction and mitigating its seismic effects.

Despite over six decades of field and laboratory investigations, theoretical studies, and advances in constitutive modeling, questions remain on the fundamental issues concerning liquefaction mechanisms, the collective influence of multiple factors on excess pore water pressure (EPWP) generation, and liquefaction triggering criteria. This paper presents the general apparent viscosity-and average flow coefficient-based methodology for quantifying the solid-liquid phase-change process of liquefiable soil under undrained cyclic loading. The analysis reveals that the evolution of the soil particle-fabric system is the fundamental physico-mechanical mechanism behind EPWP generation in a liquefiable soil, with the accompanying change in soil physical state serving as the intrinsic mechanism driving EPWP generation. The study further identifies the physico-mechanical foundations of EPWP generation, as well as the inherent causes and a unified quantitative characterization of the coupled influences of multiple factors on EPWP generation. This work presents the novel observation that the marginal peak excess pore pressure ratio (ru,pm) between the solid-liquid mixed phase and the liquid phase of liquefiable soil can be identified accurately and that ru,pm is characterized by its inherent robustness. A ru,pm value of 0.90 can be used as a liquefaction triggering criterion for soils both in laboratory element tests and in the field. Another original finding is that the liquefaction triggering resistance curve is the threshold state curve between solid-liquid mixed phase and transiently liquid phase of a liquefiable soil and is unique for a specific initial physical state. The definitions of liquefaction triggering and corresponding liquefaction triggering resistance are clear and unambiguous and have the same physico-mechanical basis. The insights obtained in this paper will potentially enable the scientific and engineering communities to reinterpret the liquefaction mechanism, its evaluation, and liquefaction mitigation strategies.

Selecting the optimal intensity measure (IM) is essential for accurately assessing the seismic performance of the submarine shield tunnels in the layered liquefiable seabed. However, current research relies on simplistic ranking or filtering methods that neglect the different contributions of each evaluation criterion on IM's overall performance. To address this, this study begins by developing a numerical simulation method for nonlinear dynamic analysis, considering joint deformation, ocean environmental loads, and soil liquefaction, which is validated by experimental and theoretical methods. Subsequently, a fuzzy multiple criteria decision-making (FMCDM) method based on fuzzy probabilistic seismic demand models (FPSDM) is proposed, which integrates the fuzzy analytical hierarchical process (FAHP) for calculating weights and the fuzzy technique for order preference by similarity to ideal solution (FTOPSIS) for ranking IM alternatives. Finally, tunnel damage is classified into four states employing joint opening as the index for measuring damage, then the seismic fragility analysis is conducted. The results indicate that the optimal IM of a submarine shield tunnel situated in layered liquefiable seabed is sustained maximum velocity (SMV). Furthermore, the comparison between the fragility curves established using SMV and peak ground acceleration (PGA) reveals PGA, a frequently employed IM, notably undervaluing the seismic hazard.

Given the likelihood of future M9 Cascadia Subduction Zone (CSZ) earthquakes, various estimates of the resulting, regional ground motions have been made, including a suite of 30 physics-based simulations that reflect key modeling uncertainties. However, because the last CSZ interface rupture occurred in 1700 CE, the shaking expected in such an event is especially uncertain, as are the impacts to the built and living environments. Like other coseismic impacts, soil liquefaction poses a significant threat and must be considered by any scenario study used to inform planning and response, or to focus mitigation resources. Liquefaction is also notable for its potential to ground truth ground-motion estimates, given that its presence or absence in the geologic record can provide constraint on the intensities of shaking in past events. It is thus an important phenomenon looking both forward and backward. Accordingly, using recent physics-based simulations, this study (1) predicts liquefaction in M9 CSZ ruptures at 400 locations in Oregon, Washington, and British Columbia (BC) using an array of cone-penetration-test based models and (2) uses paleoliquefaction evidence at ten sites spanning from Southern Oregon to Vancouver, BC to constrain possible ground-motion intensities experienced in the 1700 CE earthquake. The forward predictions indicate that liquefaction in M9 events could be pervasive in the region and affect numerous population hubs, with the potential for damage across hundreds of square kilometers. The backward analyses suggest that 1700 CE ground-motion intensities may have been less than expected from M9 simulations in some northern portions of the CSZ (e.g. Seattle), given the paucity of 1700 CE liquefaction evidence in these areas. Ultimately, further discovery and analysis of CSZ paleoliquefaction, or lack thereof, will confirm or modify this possibility and the conclusions drawn herein.

Revetment breakwaters on reclaimed coral sand have demonstrated vulnerability to seismic damage during strong earthquakes, wherein soil liquefaction has been identified as a substantial contributor. Based on the results of three centrifuge shaking table tests, this study investigates the characteristic seismic response of revetment breakwater on reclaimed coral sand and the influence of soil liquefaction. The basic mechanical properties of reclaimed coral sand were measured using undrained triaxial and hollow cylinder torsional shear tests. The centrifuge test results indicate that liquefaction of coral sand can result in significant displacement and even failure of revetment breakwaters, encompassing: (a) tilting, horizontal displacement, and settlement of the crest wall; (b) seismic subsidence in the foundation and backfill. The liquefaction consequence of the reclaimed coral sand increased with a decrease in soil density and rise in sea water level (SWL). Post-earthquake rapid reinforcement measure via sandbags is found to be effective in limiting excess pore pressure buildup in foundation soil and structure deformation under a second shaking event. Based on the test results, the effectiveness of current simplified design procedures in evaluating the stability and deformation of breakwaters in coral sand is assessed. When substantial excess pore pressure generation and liquefaction occur within the backfill and foundation coral sand, the pseudo-static and simplified dynamic methods are inadequate in assessing the stability and deformation of the breakwater.

Two earthquakes, Mw = 7.8 Kahramanmaras,-Pazarcik, and Mw = 7.6 Elbistan, occurred on February 6, 2023, approximately 9 h apart. These earthquakes caused devastating effects in a total of 11 nearby cities on the east side of T & uuml;rkiye (Adana, Adiyaman, Diyarbakir, Elazig, Gaziantep, Hatay, Kahramanmaras,, Kilis, Malatya, Osmaniye, and S,anliurfa) and the north side of Syria. These earthquakes provided an outstanding prospect to observe the effects of liquefaction in silty sand and liquefaction-like behavior in clays (cyclic softening) on the stability of structures. This paper specifically presents the post-earthquake reconnaissance at three sites and evaluations of four buildings within these sites in Adiyaman Province, Golbas, i District. First, important role of post-earthquake piezocone penetration test (CPTu) in characterizing the subsurface conditions was presented. Then, the effect of soil liquefaction and cyclic softening on the performance of four buildings during the earthquakes was evaluated. These structures represent the typical new reinforced concrete buildings in T & uuml;rkiye with 3 to 6-story, situated on shallow (raft) foundations, and demonstrated diverse structural performances from full resilience to moderate and extensive damage during the aforementioned earthquakes. Based on the interim findings from these sites, the potential factors that caused moderate to severe damage to buildings were inspected, and preliminary-immediate insights were presented on the relationship between structural design, soil properties, and the performance of buildings with shallow foundations.