基于雁型裂纹模型的高地应力巷道劈裂破坏机理分析

Analysis on the Splitting Failure Mechanism of High-Stress Roadway Based on Echelon Crack Model

基于雁型裂纹模型,对高地应力巷道的劈裂破坏形成机理进行探讨.利用应力强度因子理论,分析了雁型分支裂纹尖端的应力强度因子及其主应力,结合Hoek-Brown岩石破坏准则,得到了高地应力巷道劈裂破坏的判据.将劈裂破坏判据编成FISH语言,内嵌到FLAC软件中,计算得到围岩的劈裂破坏区域.研究表明:雁型裂纹长度越长,造成的劈裂破坏区越大.雁型裂纹长度较长时,劈裂破坏区与塑性破坏区深度相差较大.由经验公式计算出的的劈裂破坏区深度与数值模拟计算出的劈裂破坏区深度接近,表明本文提出的基于雁型裂纹模型的劈裂破坏判据可为高地应力巷道的稳定性评价及支护设计提供参考.

The splitting failure mechanism of the roadway under high-stress is studied in this paper, based on the echelon crack model. By using the stress intensity factor theory, we ana- lyze the stress intensity factor and principal stress in crack tip of echelon branch, and obtain the criterion of splitting failure in the high-stress roadway by Hoek-Brown rock failure criterion. In addition, the criterion is programmed into FISH language and embedded into FALC software, and the splitting failure zone of surrounding rock is calculated. The results show that the longer the length of echelon crack is, the larger the splitting failure area is formed. When the echelon crack length is relatively long, the difference between the depth of splitting fracture zone and depth of plastic fracture zone is large. Furthermore, the depth of splitting fracture zone calculated by empirical formula is close to the result of numerical simulation, which indicates that the splitting failure criterion proposed in this paper can provide reference for the stability evaluation and support design of high-stress roadway.