基于Weibull分布的巷道围岩开挖损伤分析

首先,在假定微元强度服从双参数Weibull分布的基础上,分析了围岩微元破坏概率和临界破坏概率,依据围岩完整程度不同,分析了巷道开挖后的围岩损伤;随后,运用岩石破裂过程分析软件RFPA,分别对不同均质度的巷道围岩开挖损伤进行了数值模拟分析。结果表明,伴随围岩均质度增加即围岩完整程度增加,围岩起始损伤延后,临界破坏概率越来越小;在围岩微元所受载荷达到其统计平均抗压强度前,围岩的均质度越低其巷道开挖后的围岩损伤值越大;在微元所受载荷达到统计平均抗压强度后,围岩均质度越高其巷道开挖后的围岩损伤值越大,其巷道开挖后的危险率越高,且往往具有突发性;巷道开挖后的围岩损伤破坏程度与围岩完整程度和抗压强度关系密切;分析结果与模拟结果是一致的。

Analysis on Surrounding Rock Damage of Roadway Based on Weibull Distribution

Based on the assume that the strength of micro-element of surrounding rock accords with double-parameter Weibull distribution,the failure probability and critical failure probability of micro-element of surrounding rock were analyzed.According to different integrity of surrounding rock its damage after roadway excavation was analyzed.The numerical simulation of excavation damage of roadway surrounding rock with different homogeneity was carried out by using a rock failure process analysis code(RFPA).The results indicated that with the increasing of the homogeneity(i.e.integrity) of surrounding rock the initial damage postponed,the critical failure probability was becoming lower.When the load of micro-element did not reach the statistical average compressive strength,lower the homogeneity was,larger the damage was.After the load of micro-element reached the statistical average compressive strength,higher the homogeneity was,larger the damage was,so surrounding rock with high homogeneity has high hazard rate,and the hazard often burst up.After excavation the damaging degree of roadway surrounding rock is closely related to its heterogeneity and compressive strength.The results of damage analysis of surrounding rock based on Weibull distribution agree with that of simulation analysis.