泥巴山隧道流纹岩加卸围压力学特性研究  

STUDY ON MECHANICAL PROPERTIES OF RHYOLITE UNDER LOADING AND UNLOADING CONDITIONS IN NIBA MOUNTAIN TUNNEL

作　　者：邓林[1] 邓荣贵[1] 付小敏[2] 刘中华[1] 苑宝军[1] 

机构地区：[1]西南交通大学土木工程学院,四川成都610031 [2]成都理工大学地质灾害防治与地质环境保护国家重点实验室,四川成都610059

出　　处：《岩石力学与工程学报》2009年第A01期3150-3155,共6页Chinese Journal of Rock Mechanics and Engineering

基　　金：2008年西南交通大学博士创新基金资助项目(2008003);交通部西部交通科技资助项目(2006318000104)

摘　　要：为了给泥巴山隧道开挖稳定性分析提供依据,选取钻孔深部的流纹岩,以隧道围岩实际应力环境为基础,结合单轴压缩破坏试验成果,进行常规三轴压缩破坏试验以及卸围压破坏试验。对流纹岩在不同试验条件下的应力–应变全过程曲线进行分析和比较,结果表明:在隧道部分深埋段,岩体的微裂隙也较发育;随着埋深的增加,岩石峰值强度有逐渐增大的趋势;完整的流纹岩抗压强度高且脆性特征明显;在三轴压缩试验时,流纹岩具有明显屈服特征,但经过很大的塑性变形后才发生宏观破坏,随着围压的增大,岩石从张性破坏向剪切破坏变化,破裂面倾角变缓;卸围压更容易造成岩石破坏,并且在卸围压破坏时其抗剪断参数c值比加围压破坏时下降48%,而?值增加11%。To provide references for stability analysis of Niba mountain tunnel construction, based on the actual stress environment and the uniaxial compression test, a series of triaxial compression and unloading tests are carried out. The rhyolite specimens are sampled from deep boreholes. The complete stress-strain curves of rhyolite specimens are analyzed and contrasted under different conditions, and the following results have been drawn. Microcracks develope in deep-buried rock mass. With the increase of buried depth, the peak strength becomes higher gradually. Integral rhyolite specimens have high compression strengths and obvious brittleness. Under triaxial compression conditions, the rhyolite specimen has obvious yield character, but macro failure happens after large plastic deformation. The failure forms turn from splitting failure to shear failure with the confining pressure increasing, and the obliquity of the fracture plane becomes gentle. Under unloading condition, the rhyolite specimens will be damaged more easily; the cohesion c is 48% lower than that under conventional compression condition, while internal friction angle φ is 11% greater than that under conventional compression condition.

关 键 词：岩石力学 泥巴山隧道 高地应力 流纹岩 卸荷破坏 力学特性 

分 类 号：TU45[建筑科学—岩土工程]