摘要
为分析块体在复杂围岩作用下的破坏形态及稳定性,提出一种基于连续介质力学的块体破坏数值分析方法.首先,在已有的单元重构-节点分离的结构面建模方法基础上,实现基于网格的块体识别;其次,基于显式求解的接触力算法,推导多种接触状态下的接触力表达式,并提出块体和围岩的接触分析方法;然后,采用结构面强度折减法求解块体安全系数.该数值分析方法可同时计算围岩和块体的变形特性.通过一个块体沿双面滑动的简单算例也论证了在一定条件下,数值计算可得到与刚体极限平衡法一致的结果;最后,结合某一断层穿过的隧洞工程,分析其开挖后的围岩及块体稳定性.结果表明,该数值方法有效反映了围岩应力和变形对块体稳定性的影响;关键块体发生破坏后,潜在危险块体发生较大变形,局部安全系数低.该数值方法为复杂地质条件下隧洞块体稳定性评价提供了一种有效的分析思路.
In order to analyze the failure mode and stability of block under complex surrounding rock,a numerical analysis method for block failure was proposed based on continuum mechanics.Firstly,based on the existing geologic plane modeling method of element reconstruction and node separation method,the grid-based block identification was carried out.Then,the expressions of contact force under various contact states were derived based on the explicit contact force method,and the contact analysis method of block and surrounding rock was proposed.Afterwards,the safety factor of block was calculated based on the strength reduction method.The numerical method can simultaneously calculate the deformation of surrounding rock and the deformation of block.A simple example of a double-plane sliding block also demonstrated that,under certain conditions,the numerical results are consistent with the results of rigid body limit equilibrium method.Finally,combined with a tunnel engineering across a fault,the stability of surrounding rock and blocks was analyzed.The results indicate that the numerical method effectively reflects the influences of stress and deformation form surrounding rock when evaluating the block stability.After failure of the key blocks,the potentially dangerous blocks occur in large deformation and the safety factor is low.This numerical method provides an effective analysis method for the stability evaluation of tunnel blocks under complex geological conditions.
作者
陈世杰
肖明
陈俊涛
CHEN Shijie;XIAO Ming;CHEN Juntao(State Key Laboratory of Water Resources and Hydropower Engineering Science,Wuhan University,Wuhan 430072,China;Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering of Ministry of Education,Wuhan University,Wuhan 430072,China)
出处
《湖南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2020年第5期31-38,共8页
Journal of Hunan University:Natural Sciences
基金
国家重点基础研究发展计划(973计划)项目(2015CB057904)
国家自然科学基金资助项目(51579191)。
关键词
隧洞
块体
接触力算法
稳定性分析
强度折减法
数值方法
tunnel
rock block
contact force method
stability analysis
strength reduction method
numerical method
