Stress drop on strong disturbance of discontinuous abutment pressure

Xue Dongjie●Zhou Hongwei●Peng Ruidong●Wang Jianqiang●Deng Linsheng●Zhao Yongwei

Abstract

Scientific quantification of disturbances in deep engineering is a prerequisite to re-understand the causes of disasters. According to the conventional triaxial compression，the Hoek-Brown and Mohr-Coulomb mechanical parameters are obtained for the coal at a depth of one thousand meter. Based on the Airey’s solution，a discontinuous stress drop is introduced on the elasto-plastic boundary for the study of continuous-discontinuous transition caused by the plastic failure，highlighting the stress drop and brittleness index assessment of the abutment pressure. A damage based on internal friction angle or cohesion degradation is defined to illustrate discontinuities in plastic zones，and is applied to the discontinuous stress distribution in three various mining layouts including non-pillar mining，top coal mining and protective coal mining. A new brittleness index is proposed considering the coupled influence of the peak stress，the stress drop，the post-peak modulus and the residual plastic strain，corresponding to the combined effect of external stress disturbances，deformation and mechanical parameters. Based on the new definition，qualitative analysis of the strong disturbed zone mainly includes the fracture zone，the post-stress unloading zone，the stress drop zone，the damage zone and the elastic zone. Finally，we proposed a new disturbance index of   based on the various mining layouts of  ，the brittleness index of  ，the stress drop of  and the in-situ stress field of  ，suggesting a clear meaning of strong disturbance when .

基于应力降的非连续支承压力强扰动特征研究

薛东杰，周宏伟，彭瑞东，王建强，邓淋升，赵永伟

摘 要 

深部扰动的科学量化定义是重新理解地下工程灾害发生原因强弱的前提。针对平顶山矿区千米埋深煤岩，基于三轴压缩试验获得Hoek-Brown与Mohr-Coulomb力学参数。基于Airey解，在弹塑性边界引入非连续应力降，突出体现为支承压力的非连续应力降与脆性指数评估，用于研究破坏后引起的连续-非连续过渡现象。引入基于内摩擦角或黏聚力的损伤应用到塑性区域以考虑非连续性，并应用于无煤柱开采、放顶煤开采与保护层开采非连续支承压力分布求解。联合峰值应力、应力降、峰前峰后模量改变与残余塑性应变定义了新的脆性指数，明确了脆性的三重内涵：外部应力扰动、变形特征与力学参量的综合影响。利用新指数定性解构了深部开挖扰动区，包括破碎区、峰后卸荷损伤区、应力跌落塑性区、峰前损伤区与内部原岩弹性升压区。最后提出基于不同开采方式 、脆性指数R、应力降 与原位应力场 定义的扰动指数 ，明确 时为强扰动。

引用格式：

Xue DJ,  Zhou HW,  Peng RD, Wang JQ, Deng LS, Zhao YW. Stress drop on strong disturbance of discontinuous abutment pressure. Chinese Journal of Rock Mechanics and Engineering ,2018: 310-310.薛东杰，周宏伟，彭瑞东，王建强，邓淋升，赵永伟.基于应力降的非连续支承压力强扰动特征研究[J]. 岩石力学与工程学报, 2018: 310-310.

DOI：10.13722/j.cnki.jrme.2017.1083

文章链接地址：

http://www.rockmech.org/CN/10.13722/j.cnki.jrme.2017.1083