动态卸荷诱发节理岩体松动的数值模拟  

Numerical Simulation of Jointed Rock Mass Loosing Induced by Dynamic Unloading

作　　者：向晓锐 吴亮[1,2] 陈洋 XIANG Xiao-rui;WU Liang;CHEN Yang(Wuhan University of Science and Technology,College of Science,Blasting Technology Research Center,CRPCE-WUST,Wuhan 430065,China;Hunan Provincial Key Laboratory of Key Technology on Hydropower Development,Changsha 410014,China)

机构地区：[1]武汉科技大学理学院中铁港航-武汉科技大学爆破技术研究中心,武汉430065 [2]水能资源利用关键技术湖南省重点实验室,长沙410014

出　　处：《爆破》2020年第1期55-60,共6页Blasting

基　　金：武汉科技大学2018年度研究生创新创业基金项目(JCX201826);国家自然科学基金项目(51479147&51779193)。

摘　　要：高地应力条件下岩体开挖面临着初始地应力动态卸荷诱发的节理松动问题。为了提出控制节理松动方案,采用理论与数值模拟方法研究了初始地应力动态卸荷诱发节理松动机理。首先,将计算模型与简单的初始应力瞬态卸载理论结果进行了对比,验证了计算模型及其参数的正确性。其次,采用动力松弛法对地应力初始化,计算了地应力水平、卸荷路径以及卸荷时长对节理岩体松动的影响。结果表明:节理岩块张开位移与卸荷时长成负相关,与地应力水平成正相关;相同条件下,指数型卸荷路径引起的节理岩体刚体位移最大,三角函数型卸荷次之,线性卸荷最小。建议工程中通过改善装药结构和孔间距等钻爆参数来增加卸荷时长,从而有效地控制节理岩体松动效应。The excavation work of rock mass under high ground stress is faced with the problem of joint loosening caused by dynamic unloading.In order to propose a scheme to control the looseness of joints,a combination of theory and numerical simulation was used to explore the mechanism of dynamic unloading induced joint loosening.The formula of joint loose displacement was derived based on elastic wave theory.The dynamic relaxation method was used to initialize the ground stress,and calculate the joint opening distance under different unloading paths,unloading time and ground stress conditions.The results show that the joint opening distance is inversely proportional to the unloading time and proportional to the ground stress level.Under the same conditions,the exponential path unloading causes the largest opening distance,the simple harmonic unloading is the second,and the linear unloading is the smallest.The root cause is still related to the length of unloading.The numerical simulation results are in good agreement with the theoretical results,and the reliability of the numerical simulation results is verified.It is suggested that the drilling blasting parameters such as the charge structure and the hole spacing be extended in the project to extend the unloading time,thereby the joint loosening effect can be controlled effectively.

关 键 词：节理岩体 地应力 动态卸载 松动变形 

分 类 号：TU45[建筑科学—岩土工程]