开挖卸荷-射孔压裂下高应力硬岩的应力分布与裂纹扩展  

Stress distribution and crack propagation of high stress hard rock under excavation unloading-perforation fracturing

作　　者：陈正红 陈秋南[1] 李夕兵[2] 吴秋红 黄小城[1] CHEN Zheng-hong;CHEN Qiu-nan;LI Xi-bing;WU Qiu-hong;HUANG Xiao-cheng(School of Civil Engineering,Hunan University of Science and Technology,Xiangtan 411201,China;School of Resources and Safety Engineering,Central South University,Changsha 410083,China;School of Resource and Environment and Safety Engineering,Hunan University of Science and Technology,Xiangtan 411201,China)

机构地区：[1]湖南科技大学土木工程学院,湘潭411201 [2]中南大学资源与安全工程学院,长沙410083 [3]湖南科技大学资源环境与安全工程学院,湘潭411201

出　　处：《中国有色金属学报》2023年第3期952-968,共17页The Chinese Journal of Nonferrous Metals

基　　金：国家自然科学基金资助项目(52004328,52078211)。

摘　　要：本文以深部硬岩矿山中射孔压裂辅助机械开挖为背景,推导了开挖卸荷-射孔压裂下应力分布理论模型,并基于离散元法建立了开挖卸荷-射孔压裂的流固耦合数值模型。通过与理论模型对比,验证了数值模型的准确性,并进一步研究了开挖卸荷下单射孔位置x_(0)、注液压力p_(t)、射孔长度h_(f)以及双射孔压裂对裂纹扩展规律的影响。结果表明:开挖卸荷-单射孔压裂下不同射孔压裂参数x_(0)、p_(t)、h_(f)对应力分布规律的影响不同。随x_(0)、p_(t)、h_(f)的增大,开挖卸荷-单射孔压裂下裂纹数量均有所增多,但裂纹扩展规律存在明显差异。在开挖卸荷-双射孔压裂下,压裂效果优于单射孔压裂,随hf的增大,裂纹数量增多,双射孔中间区域裂纹贯通。A theoretical model of stress distribution under excavation unloading-perforation fracturing was derived based on the background of perforation fracturing assisted mechanical excavation in deep hard rock mines,and a flow-coupled discrete element numerical model of excavation unloading and perforation fracturing was established.By comparing with the theoretical model,the accuracy of the numerical model was verified,then the influence of perforation position(x_(0)),injection pressure(p_(t)),perforation height(h_(f)),and dual perforation fracturing on crack propagation pattern under excavation unloading condition were investigated.The results indicate that for excavation unloading-single perforation fracturing,x_(0)、p_(t) and h_(f) have different influences on the stress distributions.The number of cracks increases with increasing x_(0)、p_(t) and h_(f),while the law of crack propagation is obviously different.For excavation unloading-dual perforation fracturing,the fracturing performance is better than single perforation fracturing,and the number of cracks increases with increasing hf,which will results the cracks coalescence in the middle area of perforations.

关 键 词：开挖卸荷 射孔压裂 应力分布 裂纹扩展 

分 类 号：TU45[建筑科学—岩土工程]