STUDY ON CREEP CHARACTERISTICS OF REGULAR ROCK MASS DISCONTINUITY

Creep characteristics of rock mass discontinuity is very important in solving the practical problems in rock mechanics. Rheological characteristic of rock mass discontinuity is one of the most important mechanical characteristics of rock mass. It controls the creep transfiguration and long-term strength. Through the shear test of dentate discontinuity on the condition of two-axes stress,this paper studies the creep characteristics of discontinuities with different slope ratios and normal stresses. By fitting and analysing the test data,the rules among normal stress,shear stress,slope ratio and creep of shear direction,normal direction and also the time-depended rules are discussed. Burgers model is used to describe the creep characteristics of discontinuities. Based on the model test,a 3D FEM program is used to analyze the mechanical properties of rock discontinuities with regular dentations during loading. Through the finite element analysis,the stress distribution of the rock mass discontinuity is studied. The failure model is discussed by the creep model test and finite element analysis;and the tension force is supposed to be the key factor for the failure of discontinuity.