The tensile deformation of fibers is often overlooked in traditional analyses of fiber reinforcement mechanisms, with pullout failure being considered as the primary failure mode in fiber-reinforced soil. In recent years, flexible fibers have increasingly been used in fiber-reinforced soil. However, their failure modes have not yet been revealed. In this study, plastic fibers are used for pullout tests conducted by a modified horizontal tensile testing apparatus. The mechanical characteristics of the fiber-soil interface and the deformation characteristics of plastic fibers have been analyzed. It has been found that the failure modes of plastic fibers in reinforced soil can be categorized into three cases: pullout failure with elastic tensile deformation, pullout failure with plastic tensile deformation, and fracture failure with plastic tensile deformation. A theoretical calculation method is proposed to describe the progressive pullout behavior, and the pullout force-displacement relationship can be determined. The pullout force calculated using this method is less than that obtained from traditional methods due to the incorporation of the fiber's deformation characteristics. Through a comparison between the pullout test results and the predicted results, the effectiveness of the proposed method in capturing the pullout force-displacement relationship of flexible fibers in soil is verified.

Tunnels, as critical underground infrastructures, often intersect with faults. Field investigations have underscored the susceptibility of fault-crossing tunnels to extensive damages during earthquakes. Hence, large-scale shaking table tests are conducted to investigate the deformation pattern and failure mechanism of faultcrossing tunnels under transverse excitation, particularly in non-rupture scenarios. The dynamic behavior of the tunnel, as expected, is dominated by the surrounding strata. Acceleration responses vary notably across different regions of the fault site. The disparity increases with the increments of seismic intensity and input frequency. The tunnel at the interface between the fault and the hanging wall manifest the strongest acceleration, where the largest strains of the tunnel and most of the lining cracks also occur, highlighting its vulnerability to seismic vibrations. The damage-induced non-linearity of the tunnel is then identified by the decreasing dominant frequency thereof. The fault-crossing tunnel exhibits unique three-dimensional shearingtorsional deformations, elucidated through the test data and an analytical model. This deformation pattern provides a better understanding of the seismic responses of fault-crossing tunnels under seismic vibrations.

Overlying river can accelerate the creep of the inner dump, so to master the creep characteristics of the overlying river can provide a theoretical basis for mine safety and discharge optimization. Taking the overlying river inner dump of Yuanbaoshan open-pit coal Mine in China as the research object, a design scheme is proposed to divide it into rolling zone and non-rolling zone. Based on the creep model obtained by in-situ deformation monitoring and laboratory rheological test, the creep evolution law and deformation of overlying channel after soil discharge, slope morphology and advancing position are simulated and analyzed. The results showed that the creep variable in the (non-) rolling zone had a nonlinear upward trend with time, and the initial upward trend was large. The maximum vertical and horizontal creep in the rolling area was located in the middle and upper part of the rolling line, while the maximum vertical and horizontal creep in the dump was located in the middle and upper part of the non-rolling area, respectively. The post-construction settlement and horizontal discharging increased with the increase of the discharge height, and the convergence creep of the top ten years after construction increased approximately linearly with the decrease of the distance from the shoulder of the inner dump. The rolled sand and gravel backfill belonged to the foundation of uniform settlement deformation in general, and the change of slope shape had little effect on the deformation of the slope top in the rolled area. The geoglage elongation in the dam area met the requirements. On the premise of ensuring the stability of the dump, the slope angle of the inner dump can be appropriately increased to increase the capacity of the inner dump. The research results can provide guidance for the construction of inner dump in open pit.