The presence of frozen soil layers leads to stratification in soil stiffness, thereby influencing the dynamic response of pile foundations in seasonally frozen soil regions. This study investigated the dynamic response of pile-soil interaction (PSI) systems in such regions. A reduced-scale (1/10) model of a pile group with an elevated cap in railway bridges was subjected to shake-table testing. During these tests, measurements were taken of soil and pile accelerations, displacement time histories, and pile strain. The acceleration amplification factor (AMF) and response spectrum of the soil and pile foundation were analyzed based on these data. Additionally, the pile-soil interaction and the dynamic shear stress-strain relationship of the soil were investigated. The experiment indicated that the presence of a frozen soil layer alters the energy dissipation order of the pile-soil interaction system. This leads to a weakened dynamic response of the pile foundation. Furthermore, the seasonally frozen soil layer acts as a filter for high-frequency ground motion, thereby mitigating resonance between ground motion and the pile foundation, ensuring the protection of the pile foundation. However, the significant stiffness contrast induced by the seasonally frozen soil can pose a threat to structural safety under increasing peak ground acceleration (PGA). As PGA increases, there is a transition from linear to nonlinear interaction between the pile and soil, initially affecting the unfrozen soil layer, then the frozen-unfrozen transition layer, and ultimately impacting the seasonally frozen soil layer.

The earthquakes in Pazarc & imath;k (Mw 7.7) and Elbistan (Mw 7.6), occurring along the East Anatolian Fault Zone (EAFZ) on February 6, 2023, caused significant damage and destruction to the built environment within the affected area. In this study, the preliminary site investigations were conducted in the G & ouml;lba & scedil;& imath; district, where the impacts of both earthquakes were severely felt, offering scientifically valuable information regarding the soil damage. Comprehensive liquefaction analyses were performed using the geotechnical laboratory test data on soil specimens collected from the G & ouml;lba & scedil;& imath; district. These analyses confirmed the liquefaction-induced ground failures observed immediately after the two earthquakes. Furthermore, microzonation data collected in the G & ouml;lba & scedil;& imath; district were consolidated, and seismic site response analyses were conducted. Simulations showed that local soils in the region could amplify seismic waves by a factor of two. Utilizing the calculated Peak Ground Acceleration (PGA) and amplification factors, GIS-based distribution maps of the entire area were developed. These maps serve as practical resources for practitioners and local planners, aiding in spatial settlement decisions and urban transformation planning. They contribute significantly to enhancing the understanding of earthquake hazards in the region.