NUMERICAL INVESTIGATION OF DYNAMIC RESPONSE AND INSTABI-LITY MECHANISM FOR DANGEROUS ROCK MASS SLOPE UNDER EARTHQUAKE LOADS

The paper models the dynamic response for dangerous rock mass slope with a bedding structural plane under earthquake loads using the fast lagrangian analysis of continua. Based on time-history analysis method, the law of dynamic response is analyzed and its instability mechanism is also investigated. The results show that there are vertical and free surface amplification effects in the distribution of horizontal acceleration and velocity within the dangerous rock mass slope. The results are obviously influenced by the structural plane, discontinuous phenomena of acceleration, velocity, displacement and shear stress. Its peak horizontal displacements reduce gradually upward when it is below the structural plane, increase suddenly when across the structural plane and continue to reduce gradually upward when above it. Obviously, the amplification factor for horizontal displacement in the dangerous rock mass is larger than that in the mother rock mass. It is conducive to the further study the dynamic characteristics of the structural plane and dynamic instability mechanism for dangerous rock mass slope.