中文摘要：

针对现有研究无法有效评价裂隙分布特征对围岩变形破裂影响程度的问题,以一个软岩巷道工程为背景,考虑裂隙的5种形态分布特征：距巷道的中心距离、方位角、倾角、长度和宽度,并在此基础上进行PFC^3D正交数值模拟试验设计。结果表明：当裂隙穿过巷道时,斜向裂隙更容易导致巷道周边岩体发生大变形或局部垮塌,其危险程度要大于水平裂隙,更大于竖向裂隙;当裂隙未穿过巷道时,如裂隙附近岩体处于相对容易破裂的位置,则巷道岩体就会在裂隙距巷道表面最近的位置产生一条新的连通至巷道表面的破裂通道;裂隙方位角和裂隙宽度是影响巷道表面围岩收敛变形的最主要因素,而裂隙方位角和裂隙长度则对巷道横断面围岩的破裂扩展起着决定性作用。

英文摘要：

Because the existing research cannot effectively evaluate the influence degree of deformation and fracture of surrounding rock which affected by fracture distribution,with the background of soft rock tunnel project,five kinds of fracture distribution characteristics are considered which including distance from the center of the tunnel,azimuth,inclination,length and width,and basis on this,PFC^3D orthogonal numerical simulation is designed. The results show that：（ 1） when fracture pass through the tunnel,oblique fracture would more easily lead to a major deformation or partial collapse of surrounding rock,its risk level is greater than horizontal fracture and more greater than horizontal fracture,（ 2） if the rock mass near the fracture which was not pass through the tunnel was in a relatively easy rupture location,the surrounding rock would generate a new fracture channel to the surface of tunnel in the fracture location that nearest from the tunnel surface,（ 3）the fracture azimuth and fracture width were the most important factor for surface convergence deformation of tunnel,besides,the fracture azimuth and fracture length played a decisive role in the fracture extension of the cross section of tunnel.