不同侧压力系数下圆形巷道变形破裂规律分析

发布时间：2018-06-03 00:29

本文选题：安全工程 + 侧压力系数　；参考：《安全与环境学报》2017年02期

【摘要】：为研究侧压力系数对巷道周边岩体稳定性的影响,以一条深埋圆形巷道工程为背景,采用离散颗粒元软件PFC3D分析了5种侧压力系数下巷道周边岩体的应力差、位移、破裂分布模式和微裂纹数等,得到了圆形巷道周边岩体应力、变形和破裂随侧压力系数的变化规律。结果表明,1)随侧压力系数增大,巷道顶底部浅部岩体主应力差先增大后减小,深部岩体主应力差逐渐增大;而巷道两帮浅部岩体主应力差变化较小,深部岩体主应力差先减小后增大。这表明在相同埋深情况下,高侧压力系数不一定会对帮部岩体造成更大的破坏,但更容易使顶板产生高剪应力,不利于顶板岩体的稳定。2)侧压力系数越大,巷道顶板岩体竖向位移就越小,且其由拱顶往外平滑递减的规律性也越不明显,而帮部岩体水平位移变化规律与顶板岩体相反。3)巷道顶底部围岩在侧压力系数较大的情况下较易发生破裂,并随侧压力系数增大,其破裂范围越来越大;巷道两帮岩体则在不同侧压力系数下均会发生破裂,且其破裂范围随侧压力系数增大而略减小。4)不同侧压力系数下,巷道岩体总裂纹数都随开挖时间呈指数增长;且当巷道开挖完成后,岩体总裂纹数与侧压力系数呈抛物线关系。
[Abstract]:In order to study the influence of lateral pressure coefficient on the stability of surrounding rock mass of roadway, the stress difference and displacement of surrounding rock mass under five kinds of lateral pressure coefficients are analyzed by using discrete particle element software PFC3D under the background of a deep buried circular roadway project. The stress, deformation and rupture of surrounding rock mass of circular roadway are obtained according to the fracture distribution pattern and the number of micro-cracks, and the variation law of rock mass stress, deformation and fracture with the lateral pressure coefficient is obtained. The results show that with the increase of the lateral pressure coefficient, the principal stress difference of the shallow rock mass at the top and bottom of the roadway increases first and then decreases, and the principal stress difference of the deep rock mass increases gradually, while the main stress difference of the two sides of the roadway is small. The principal stress difference of deep rock decreases first and then increases. This indicates that under the same buried depth, the high lateral pressure coefficient will not necessarily cause more damage to the rock mass, but it is more likely to cause high shear stress on the roof, which is not conducive to the stability of the roof rock mass. 2) the larger the lateral pressure coefficient, the greater the lateral pressure coefficient is. The smaller the vertical displacement of roadway roof rock is, the less obvious is the regularity of smooth decline from arch roof to outside. The horizontal displacement of the roof rock mass is contrary to that of the roof rock mass. 3) the rock mass at the top and bottom of the roadway is prone to fracture under the condition of larger lateral pressure coefficient, and with the increase of the lateral pressure coefficient, the fracture range becomes larger and larger. On the other hand, the rock mass of two sides of roadway will be ruptured under different lateral pressure coefficients, and the fracture range decreases slightly with the increase of lateral pressure coefficient .4) under different lateral pressure coefficients, the total number of cracks in roadway rock mass increases exponentially with the excavation time. When the tunnel excavation is completed, the total crack number of rock mass is parabolic with the lateral pressure coefficient.
【作者单位】：河南理工大学土木工程学院;中国矿业大学深部岩土力学与地下工程国家重点实验室;
【基金】：国家重点基础研究发展计划973项目(2014CB046905) 河南理工大学博士基金项目(B2017-51)
【分类号】：TD322

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