摘要
Fracture persistence is an essential parameter to evaluate the stability of rock mass.The calculation of three-dimensional(3D)fracture persistence has always been a difficulty in rock mechanics.In the present study,a projection method based on fracture network modeling is employed to study the 3D fracture persistence of abutment rock mass in Wudongde dam area.According to the engineering geological conditions,the potential sliding boundaries of abutment rock mass on each bank are determined.Subsequently fracture networks are constructed by an inverse method.In fracture networks,projection planes with different sizes,different positions and different orientations are set to calculate 3D fracture persistence.The scale effects,distribution characteristics and the changes of persistence on lateral slip surface with directions are discussed.The following conclusions are drawn from the study:(1)the lateral slip surface has marked scale effect whereas bottom slip surface does not;(2)due to the inhomogeneous rock mass,the distribution type of 3D persistence of lateral slip surface are approximately normal.The mean value of persistence of lateral slip surface on left bank is 3.9% and that on right bank is 8.1%;(3)the persistence of lateral slip surface varies with the directions changes.The steep dip of projection plane corresponds to a low persistence value of lateral slip surface.The study provides a parameter basis for evaluating the stability of abutment rock mass in Wudongde dam area.