A new ring-shear device for testing rocks under high normal stress and dynamic conditions

摘要

A new ring-shear device was developed to investigate the sliding mechanism of earthquake-triggered large rock avalanches. The loading capacity of the new device is adequate to apply dynamic normal force and torque to a rock specimen to simulate the dynamic stress path of the sliding surface in an earthquake. A rock sample taken from Cholan Formation at the Tsaoling landslide site, which was triggered by the 1999 Chi-Chi earthquake, was the primary test material investigated. The failure conditions of the sliding surface and the effect of seismic inertial force on the sliding blocks are considered as the terms of this test. The experimental results reveal that different cumulative shear displacements under different initial normal stresses. The accumulated shear displacements with and without seismic inertial forces are 38.7 mm and -2 mm, respectively. The negative accumulated shear displacement indicates an abnormal sliding orientation that moved toward the top of the slope. Therefore, the new ring-shear device is a useful tool in realizing the dynamic behavior and shear mechanics of the sliding surface of an earthquake-triggered large rock avalanche.