基于PFC^(3D)的深埋圆形巷道变形破裂时效特征分析  

PFC^(3D)-Based Analysis of the Time-Dependent Characteristics of Rock Deformation and Fracturing around a Deeply-Buried Round Tunnel

作　　者：林志斌[1] 李元海[2] 高文艺[2] 杨帆[2] 

机构地区：[1]河南理工大学土木工程学院,焦作454000 [2]中国矿业大学深部岩土力学与地下工程国家重点实验室,徐州221116

出　　处：《现代隧道技术》2017年第2期73-80,共8页Modern Tunnelling Technology

基　　金：国家自然科学基金项目(51174197);国家重点基础研究发展计划973项目(2014CB046905)

摘　　要：深部岩体的变形破裂时效特征是事关巷道稳定性与控制的关键问题,文章以某深埋巷道工程为背景,采用离散颗粒元软件PFC^(3D)以及物理模型试验分析了巷道周边岩体的变形破裂时空演变规律与机理。研究结果表明:(1)巷道围岩变形与巷道开挖时间呈"台阶式"增长关系,与其距巷道表面的距离则呈指数衰减关系;(2)随着巷道向前推进,巷道两帮岩体会在拱腰附近出现往深处以及顶底板方向逐渐扩展的剪切滑移裂纹,同时其裂纹数目、破裂分形维数值将呈指数衰减式增长变化;(3)巷道岩体剪应力传递是一个滞后和衰减的过程,巷道开挖将使巷道两帮浅部岩体剪应力迅速增大而发生屈服破裂现象。当发生屈服时,该处岩体剪应力将往深处传递,导致邻近岩体发生延性剪切破坏,进而产生明显的剪切滑移裂纹。The time-dependent characteristics of rock deformation and fracturing are key issues concerning the stability and control of deep tunnels. Based on a deeply-buried tunnel, the discrete particle flow code software PFC^3D and a physical model test were used to analyze the spatio-temporal evolution law and mechanism of rock deformation and fracturing around the deep roadway. The research results show that： 1） the deformation of the roadway surrounding rock has a ＂step＂ growth relationship with the excavation time and has an exponential decay relationship with the distance from the roadway surface; 2） moving forward, shear slip cracks occur at two sides of the roadway near the haunch and gradually expand toward the roof and floor, with the number of cracks and rupture fraetal di- mension increasing in an exponential decay; and 3） the shear stress transfer of the tunnel rock mass is a process of lagging and attenuation, the shear stress of the shallow-buried rock mass at two sides of the tunnel increases rapidly and results in a yield fracture, and the shear stress of the rock mass at that place transfers more deeply and leads to ductile shear failure of the nearby rock, and obvious shear slip cracks occur.

关 键 词：PFC^3D变形破裂 时空演变 主应力差 

分 类 号：U456.31[建筑科学—桥梁与隧道工程]