ON EFFECT OF NON-PERSISTENT JOINTS ON HYDROMECHANICAL BEHAVIOR OF JOINTED ROCK MASS IN UDEC

The existence of non-persistent joints will weaken the strength of rock mass and affect the mechanical behavior of rock mass which leads to change in the permeability of rock mass. A damage variable is introduced to account for weakened effect on strength of rock mass. It is defined as the ratio of the sum of actual length of all non-persistent joints in a block to the sum of length of all fictitious joints which are extensions of all non-persistent joints to the boundary of the block. According to the damage variable, the elastic modulus is deducted. Based on UDEC, a subroutine named damage_var is generated to calculate the damage variable and assign new properties to each block. Finally, numerical uniaxial compressive tests and the Hydro-Mechanical (HM) coupling calculations are carried out to study the effect of non-persistent joints.