The K & uuml;& ccedil;& uuml;k & ccedil;ekmece-Avc & imath;lar corridor of the D100 highway constitutes a critical component of Istanbul's transportation infrastructure. Given its strategic importance, ensuring its operational continuity following the anticipated major Istanbul earthquake is imperative. The aim of this study was to investigate the liquefaction-induced geotechnical risks threatening the K & uuml;& ccedil;& uuml;k & ccedil;ekmece-Avc & imath;lar segment of the D100 highway. Initially, the study area's liquefaction susceptibility was assessed through Liquefaction Potential Index mapping. Subsequently, post-liquefaction ground displacements were quantified using semi-empirical methodologies and advanced numerical analyses focused on representative critical sections. Numerical simulations incorporated various constitutive models for liquefiable soils, enabling a comparative assessment against semi-empirical estimations. The results revealed that semi-empirical approaches systematically overestimated the lateral displacements relative to numerical predictions. Moreover, the analyses highlighted the sensitivity of model outcomes to the selection of constitutive parameters, underscoring the necessity for careful calibration in modeling liquefiable layers. Despite considering the most conservative displacement values from numerical analyses, findings indicated that the D100 highway is likely to experience substantial damage, potentially leading to extended service disruptions following the projected seismic event.

The 2020 Mw 6.4 Petrinja, Croatia, earthquake triggered widespread liquefaction along the Kupa, Glina, and Sava rivers. The locations of liquefaction ejecta and lateral spreading were identified through a combination of field reconnaissance and interrogation of aerial photographs. Superimposing those locations on the regional geologic map revealed the liquefaction vulnerability of Holocene terrace and flood deposits, Holocene deluviumproluvium, and Pleistocene loess deposits. Liquefaction caused damage to the land and structures, with ejecta observed both near and far from residential structures. In the free field, the ejection of silty and sandy soil accompanied the extensive ground fracturing. At residential properties, ejecta led to differential settlement, cracks in foundations, walls, and floors, and contamination of water wells. Lateral spreading resulted in the formation of ground and building cracks, house sliding and tilting, pipe breakage, and pavement damage. This article documents these observations of liquefaction and draws conclusions regarding the patterns of liquefaction observed in this earthquake. These observations will be a valuable addition to liquefaction triggering databases as there are relatively few earthquakes with magnitudes less than 6.5 that triggered extensive liquefaction, and they provide additional case histories of liquefaction in Pleistocene deposits.

At 4:17 am (1:17 UTC) on Feb. 6, 2023, an earthquake with Mw=7.8 struck near Pazarc & imath;k City in south-central Turkey, followed by a 7.5 Mw event about 9 h later. The subsequent earthquakes can cause severe damage which might not be the case for single earthquakes. In this study, a series of shake table tests on level ground with a sloping base model were conducted to investigate the effects of subsequent liquefactions on two 2 x 2 pile groups with a minor fixity in the caps. Adequate time intervals for complete dissipation of excess pore water pressure in the liquefiable layer were permitted at the end of each shaking. For this purpose, the free field soil and the piles were sufficiently instrumented to measure various parameters during and after the shakings. In this paper, the results of one of the shakings are reported and discussed in detail, and the results of other shakings are compared. The reported results contain time histories of acceleration, displacement, pore water pressure, bending moment, shear force, and lateral pressure on the piles. The ground settlements due to subsequent earthquakes are also measured and reported. The findings reveal that in a level ground liquefiable layer overlying a sloping base, lateral spreading may also occur and affect the piles behaviour especially in subsequent earthquakes. In addition, a practical relationship is proposed from the experimental results to estimate the residual shear strength of the liquefied soil.

The present study documents coastal processes of movement and subsidence that affect the clayey sediments of the exposed mudflats ('mudflat sediments') on the receding western shore of the Deep Dead Sea ('western Dead Sea shore') and the formation of subsidence features: subsidence strips and clustered sinkholes. The properties of the clayey sediments that promote movement and subsidence and the development of the subsidence features in the exposed mudflats are the unconsolidated fine-particle texture composed of clay and carbonate minerals, their being dry near the surface and wet at the subsurface, their soaking with saline water and brine and the abundance of smectitic clays saturated with sodium and magnesium. Field observations indicate that narrow subsidence strips with/without clustered sinkholes were developed by movement and subsidence in mudflat sediments via lateral spreading. Wide subsidence strips with clustered sinkholes were developed via increased subsidence in mudflat sediments due to the progress of dissolution within a subsurface rock-salt unit. The emergence of sinkholes occurs via subsidence of mudflat sediments into subsurface cavities resulting from dissolution within a subsidence rock-salt unit. The coastal processes on the receding Dead Sea shore and the formation of the subsidence features are part of the adjustment of the Dead Sea periphery to the lowering of the base level. A contribution of slow mass movement seaward to the coastal processes on the receding Dead Sea shore is indicated.

This paper employs three-dimensional parallel finite elements to assess the seismic response and resilience of various pile group configurations. The numerical model was verified in the literature through two large-scale shaking table tests. A parametric study was conducted to depict the influences of pile number (N), position within a pile group, pile nonlinearity, and frequency content on the seismic response in sloping liquefiable soils. The result showed that the importance of these factors on the analysis and design for the pile groups, while they are not considered in the current design codes including Japan Road Association (JRA) 2002 and American Petroleum Institute (API). Furthermore, the API method most likely underestimates P-y at shallow depths rather than numerical analysis results, while it overestimates at deeper burial depths. In addition, JRA code overestimates the monotonic soil pressure in the infinite pile group and underestimates it in the finite pile group. In other words, the difference between the computed soil pressure from JRA and the numerical model decreases with N. The asymmetry ratio (AR) is also important for the acceleration response, since AR decreases with N. Also, it has been shown that the seismic responses increase in corner piles with the N due to the increasing stiffness. Subsidence at the downslope side of the pile group and heave at the upslope side of the one occurs and increases with N. Nonlinear pile behavior increases maximum displacements, especially in central piles, while reducing internal forces in corner piles. Corner and side piles yield earlier, requiring middle piles to sustain greater forces under continued lateral spreading.

The liquefaction-induced lateral spreading of the fluvial terraces can cause tremendous physical damage to the natural and built environments in the lower reaches of Yangtze River. This paper presents an integrated nonlinear site response analyses method to characterize the large-scale lateral spreading behavior in the wide river valley of Yangtze River at the scale of several kilometers in the Abaqus/Explicit code, incorporating the main features such as the spatial variability of liquefiable deposit, the liquefaction initiation and cyclic mobility at the post liquefaction stage and the geometric nonlinearity induced by the extensively large deformation. In particular, the large-deformation behavior in the numerical model is simulated by the plasticity-based model at the element level and the arbitrary Lagrange-Euler (ALE) method at the model mesh level. The key factors influencing lateral spreading behavior are investigated, involving the ground motion characteristics, the slope angle of fluvial terraces, and the spatial variability of site condition. The numerical results indicate significant spatial variation characteristics of the lateral spreading of the fluvial terraces, triggered in the slightly inclined slope. Three generation stages of lateral spreading could be identified in the time-history curve of lateral displacement, i.e. swing stage, slip stage and creep stage, respectively. Finally, the model performance of the proposed modelling method is evaluated against the widely-used empirical formula, and the difference between each other is interpreted, which provides new insights into the mechanism of liquefaction-induced lateral spreading of the fluvial terraces in the wide river valley.

Two disastrous earthquakes, named Pazarc & imath;k (Mw7.8) and Ekin & ouml;z & uuml; (Mw7.6), occurred on February 6, 2023 in the southeast part of T & uuml;rkiye and were collectively named Kahramanmara & scedil; earthquakes. These seismic events were caused by a left lateral strike-slip faults, and resulted in significant loss of life, severe damage to infrastructures and buildings, and geotechnical damages such as mainly large-scale slope failures, rockfalls, and ground liquefaction. The main goal of this study is to assess the extend and impact of widespread ground liquefaction, particularly on built environment. Additionally, the ranges of amount of settlement and tilting of buildings due to ground liquefaction were briefly discussed and liquefaction caused by Kahramanmara & scedil; earthquakes were compared with those others occurred in T & uuml;rkiye. The site observations indicated that except a village, a short of a highway, a few bridges and two settlements, widespread liquefaction was mainly observed in agricultural non-urbanized fields. The maximum amount of settlement at some liquefaction locations reached up to 2 m and high-raise buildings tilted 7-8 degrees from the vertical reaching up about 20 degrees. Observations indicated that single-storey and two-storeys buildings with a basement to a certain depth, a lower center of gravity and raft foundation should be considered suitable on soils susceptible to liquefaction in earthquake-prone regions without taking any counter-measures against ground liquefaction. Mass movements along the shoreline of the G & ouml;lba & scedil;& imath; Lake were unlikely to be caused by lateral spreading resulting from ground liquefaction and they were rather due to planar sliding along a weak layer dipping towards the lake with progressive failure.

Post-earthquake investigations have shown that piles in liquefiable soils are highly susceptible to damage, especially in sloping sites. This study examines the seismic performance of pile groups with lateral spreading through advanced numerical modeling. A three-dimensional finite element model, validated against large-scale shaking table test results, is implemented to capture the key mechanisms driving the dynamic response of pile groups under both inertial and kinematic loading conditions. Parametric seismic response analyses are conducted to compare the behavior of batter and vertical piles under varying ground motion intensities. The results indicate that batter piles experience increased axial compressive and tensile forces compared to vertical piles, up to 70% and 20%, respectively. However, batter piles provide enhanced lateral stiffness and shear resistance compared to vertical piles, reducing horizontal displacements by up to 20% and tilting the cap by 85% under strong ground motion. The results demonstrate that batter piles not only enhance the overall seismic stability of the structure but also mitigate the risk of liquefaction-induced lateral spreading in the near-field through pile-pinning effects. While vertical piles are more commonly used in practice, the distinct advantages of batter piles for seismic stability highlighted in this study may encourage using more advanced numerical modeling in engineering projects.

Liquefaction-induced lateral spreading poses a significant threat to buried structures during earthquakes occurring on gentle slopes. This study investigates the influence of ground slope and soil relative density on liquefaction-induced lateral spreading using shaking table experiments. Two physical models with varying ground slopes (2%, 5%, and 8%) and soil relative densities (20%, 40%, 60%, and 80%) were constructed, and seven tests were conducted using a rigid box configuration with Plexiglas sides for visual observation and image processing. Particle Image Velocimetry (PIV) was employed to analyze soil layer deformations. The findings indicate that higher soil relative density leads to increased soil stiffness and acceleration amplitudes across all soil layers, while steeper slopes induce higher acceleration spikes before liquefaction. Moreover, an increase in soil relative density significantly reduces excess pore water pressure (EPWP) buildup, thereby mitigating lateral spreading. Conversely, variations in gentle ground slope shows a minimal impact on EPWP. The PIV analysis indicates that the maximum horizontal displacements occur in the middle layer for 20% relative density, gradually shifting towards the upper third with increasing density. The study observed two displacement phases: localized shear rupture, which were uniform across densities, and lateral spreading, which were dominant at 20% and 40% densities. Higher soil density leads to reduced lateral movement and settlement. The ground slope causes a minor increase in localized lateral movement but has minimal impact on overall settlement.

Lateral spreading is one of the most common secondary earthquake effects that cause severe damage to structures and lifelines. While there is no widely accepted approach to predicting lateral spread displacements, challenges to the existing empirical and machine learning models include obscurity, overfitting, and reluctance of practical users. This study reveals patterns in the available lateral displacement database, identifying rules that describe the significant relationships among various attributes that led to lateral spreading. Seven conditional attributes (earthquake magnitude, epicentral distance, maximum acceleration, fines content, mean grain size, thickness of liquefiable layer, and free -face ratio) and one decision attribute (horizontal displacement) were considered in modeling a binary class rough set machine learning. There are eighteen rules generated in the form of if -then statements. The decision support system reveals that the severity of lateral spreading clearly comes from the combinations of relevant attributes. Moreover, five clusters of rules were also observed from the generated rules. Useful information regarding the different lateral spreading case scenarios emerges from the results. Statistical validation and interpretation of rules using principles of soil mechanics and related studies were also performed. The output of this study, a decision support system, can be very useful to decision -makers and planners in understanding the lateral spreading phenomena. Recommendations for the model improvement and for further studies were discussed.