深埋洞室岩体开挖卸荷诱导的围岩开裂机制  

CRACKING MECHANISM OF SURROUNDING ROCK INDUCED BY RELEASE OF EXCAVATION LOAD IN DEEP TUNNEL

作　　者：杨建华[1,2] 张文举[1,2] 卢文波[1,2] 陈明[1,2] 严鹏[1,2] 

机构地区：[1]武汉大学水资源与水电工程科学国家重点实验室,湖北武汉430072 [2]武汉大学水工岩石力学教育部重点实验室,湖北武汉430072

出　　处：《岩石力学与工程学报》2013年第6期1222-1228,共7页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家杰出青年科学基金项目(51125037);国家自然科学基金面上项目(51279135);武汉大学博士研究生学术新人提名奖资助项目(T2011206009)

摘　　要：针对深埋圆形隧洞爆破开挖,采用双向受压条件下的压剪裂纹扩展模型和应力强度因子计算公式,分析开挖面上岩体应力瞬态释放和邻近的围岩应力瞬态调整对围岩开裂过程的影响。结果表明,与准静态卸载条件相比,开挖面上岩体应力瞬态释放在围岩中产生附加动应力,导致围岩径向卸载和环向加载效应放大,加剧了深埋洞室围岩开裂效应,导致开裂范围增大;开挖卸载速率越快,围岩中产生的附加动应力幅值越大,围岩的开裂效应越显著。For a case of circular deep tunnel,the effect of abrupt in-situ stress release in terms of cracking in surrounding rocks is investigated by adopting an initiation model of cracks under biaxial compressions.In addition,a formula of the stress intensity factor is employed.The results show that,compared to a quasi-static process of stress release,the transient release of in-situ stress on excavation face generates an additional dynamic stress in surrounding rocks.In this circumstance,the radial unloading and the circumferential loading are enlarged by this additional stress,thus cracking in surrounding rocks is aggravated during this transient process.The shorter the release duration of stress is,the greater the amplitude of the additional stress and the cracking extent become.

关 键 词：岩石力学 深埋隧洞 岩体开裂 爆破开挖 应力瞬态释放 

分 类 号：TU45[建筑科学—岩土工程]