Deformation and failure mechanism of overlying soil lavers under strike-slip fault action

With the advancement of the western development, engineering projects inevitably need to traverse fault zones. However, fault zones are typically characterized by frequent seismic activities and rock layer dislocations, which bring certain challenges to both construction and resource development. To explore the sensitivity factors affecting the sensitivity of cross-fault engineering structures, this study investigates the effects of different bedrock dislocation amouts, bedrock dislocation rates, fault-crossing angles, different types of soil at the site, and varying soil thicknesses on the deformation, failure, and vertical stress mechanisms of overlying soil layers. The results show that bedrock dislocation can lead to stress concentration, fractures, sliding, and other destructive phenomena in overlying soil layers. These damages may cause soil displacement, potentially triggering geological hazards such as landslides, ground slides, and ground deformations. This poses a high risk of damage and destruction of the underground pipelines, roads, bridges, and other engineering facilities. This paper focuses on issues such as ground settlement deformation and collapse caused by rock dislocation, revealing that with an increase in rock dislocation amount, different types of soil at the site exhibit varying degrees of increase in settlement displacement and vertical stress on the overlying soil layer. For example, with the bedrock dislocation amount of 2 m compared to 0.4 m in hard soil, settlement deformation and vertical stress increase by around five times. In addition, it was found that selecting a 90° angle for fault crossing can reduce settlement deformations and stresses. The study aims to reveal the deformation damage of the overlying soil layer, providing technical support for the inevitable deformation of cross-fault engineering structures as well as the reinforcement against shear damage.