This study quantifies the seismic fragility assessment of shallow-founded buildings in liquefiable and treated soils, enhanced by drainage and densification, considering both short-and long-term behaviors. A conceptual framework is proposed for developing seismic fragility curves based on engineering demand parameters (EDPs) of buildings subjected to various earthquake magnitudes. The framework for establishing seismic fragility curves involves three essential steps. First, nonlinear dynamic analyses of soil-building systems are performed to assess both the short-term response, which occurs immediately following an earthquake, and the longterm response, when excess pore water pressure completely dissipates, and generate a dataset of building settlements. The seismic responses are compared in terms of excess pore water pressure buildup, immediate and residual ground deformation, and building settlement to explore the dynamic mechanisms of soil-building systems and evaluate the performance of enhanced drainage and densification over short-and long-term periods. Second, 38 commonly used and newly proposed intensity measures (IMs) of ground motions (GMs) are comprehensively evaluated using five statistical measures, such as correlation, efficiency, practicality, proficiency, and sufficiency, to identify optimal IMs of GMs. Third, fragility curves are developed to quantify probability of exceeding various capacity limit states, based on structural damage observed in Taiwan, for both liquefaction-induced immediate and residual settlements of buildings under different levels of IMs. Overall, this study proposes a rapid and straightforward probabilistic assessment approach for buildings in liquefiable soils, along with remedial countermeasures to enhance seismic resilience.

The utilization of cone penetration test (CPT & CPTu) results to assess the bearing capacity of deep foundations stands as a crucial application in geotechnical engineering. This study focuses on leveraging the outputs of the CPT test, considering the distinctive features of piles and the abundance of reliable information, coupled with the rapidity of the test. The CPT test outcomes can be employed both directly and indirectly to ascertain the capacity of the toe and shaft resistance of piles. In seismic conditions, applying earthquake acceleration to sensitive and liquefiable soils induces an increase in pore water pressure Delta u, leading to a subsequent reduction in soil strength. Thus, investigating changes in excessive pore water pressure serves as a key dynamic load indicator in seismic scenarios. This research initially determines the bearing capacity of deep foundations through common methods using CPT data. Subsequently, key parameters influencing the development and dissipation of Delta u, such as soil sensitivity (St), undrained shear strength (Su), and dimensionless parameters of pore water pressure 1-Bq\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\left( {1 - B_{q} } \right)$$\end{document} and 1-u2qt\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\left( {1 - \frac{{u_{2} }}{{q_{t} }}} \right)$$\end{document}, are meticulously evaluated. This study proceeds to investigate the impact of these parameters on the bearing capacity of deep foundations, drawing insights from a comprehensive database encompassing CPT & CPTu data from 18 diverse sites worldwide. Comparative analysis between the proposed method and conventional approaches reveals a significant reduction in the aforementioned parameters' influence on the bearing capacity of deep foundations. Consequently, this finding underscores the necessity of incorporating such considerations in geotechnical bearing capacity calculations for projects situated on soils prone to liquefaction.

Large diameter shield tunnels traversing liquefiable soil-rock strata are highly susceptible to seismic hazards, as earthquake-induced soil liquefaction significantly reduces soil strength and stiffness. Therefore, it is crucial to accurately assess the seismic performance of these tunnels. This study first establishes a numerical model for tunnel seismic response analysis, considering soil liquefaction, segment nonlinearity, and joint deformation. The validity of the model is affirmed through experimental, theoretical, and additional numerical simulations. The probabilistic seismic demand models are established employing the seismic database consisting of 120 ground motion records. Subsequently, a quantitative selection method for the optimal Intensity Measure (IM) based on fuzzy comprehensive evaluation is proposed, identifying Velocity Spectrum Intensity (VSI) as the most suitable among 29 commonly used IMs, and the IMs related to duration exhibit poor performance. The study then categorizes tunnel damage into three states: minor, moderate, and extensive, using joint opening as the damage measure. Finally, seismic fragility analysis is employed to assess seismic performance of tunnel, and fragility curves derived using VSI and Peak Ground Acceleration (PGA) is compared. The results indicate that PGA, a commonly used IM, significantly underestimates the probability of damage to the tunnel, with a maximum underestimation of 22.4%.

Historical data has shown that soil-structure systems exhibit increased severity when subjected to earthquake sequences, attributed to the accumulated instability of soil deposits and the cumulative damage of structures. This study analyzes seismic responses of multi-story buildings and mechanical behavior of liquefiable soil deposits under repeated shake-consolidation process. This is achieved through a series of numerical simulations using a finite element-finite difference (FE-FD) code, namely DBLEAVE-X. Sequential earthquakes are obtained from the NGA-West2 PEER ground motion database and recalibrated relied on various aspect ratios, including peak ground acceleration ratios (rPGA) and consolidation time (Tgap). The numerical results reveal that shearinduced and residual settlements of buildings during sequential earthquakes might be notably larger than that during single earthquakes. The repeated shake-consolidation process has a significant impact on development and dissipation of excess pore water pressure (E.P.W.P), notably influencing the deformation response of both buildings and ground deposits. The findings also provide valuable insights into effects of both complete and partial consolidation processes on seismic mechanisms of entire liquefiable soil-structure systems. Numerical observations suggest that multi-story buildings under sequential earthquakes might be more vulnerable, underscoring the necessity of integrating sequential earthquakes into earthquake-resistant building design.

The typical undrained behaviour observed in brittle non-plastic soil is ruled by the combination of density and stress levels. Some specific silty and sandy mining waste with particles morphologies that generate high small-strain stiffness to strength ratios when increasing deviatoric stress (q) in stress paths that tend to decrease mean effective stress (p ') may drop down the deviatoric stress before reaching the frictional critical sate. The ratio between the peak (or yield) value (S-u=q/2) and the corresponding p ' is usually associated with a locus in q-p ' that is commonly associated to a straight Instability Line (IL) with a unique ratio (eta(IL)) and for an initial state parameter. However, this is not the case if an induced anisotropy is installed differently while the at rest stress ratio (hereby defined as initial, K-0) is achieved by continuous rate the principal stresses consolidated in lab prior to loading with distinct values. This fabric effect is decisive for design and in stability assessment of earth structures, like dams or piles of mine tailings where non-plastic fines are dominant, even if the prevailing stress-path is in compression. In a thorough and quite complete program varying these conditions on iron ore tailings from Minas Gerais state in Brazil, reconstituted in lab with differentiated state parameters, and its relation to the induced anisotropy effect.