不同三轴应力途径下红砂岩力学特性试验研究  

Study on red sandstone mechanical property under different stress path by triaxial test

作　　者：胡卸文[1,2] 伊小娟[1] 王帅雁[1] 黄润秋[2] 

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

出　　处：《水文地质工程地质》2009年第4期57-61,共5页Hydrogeology & Engineering Geology

基　　金：国家自然科学基金项目(40772175,40841025);国家科技支撑计划课题(2008BAG07B01)资助;地质灾害防治与地质灾害保护国家重点实验室“科技减灾、重建家园”开放基金(DZKJ-08012);西南交通大学科学研究基金(2008-A01)

摘　　要：针对大量地下工程(交通隧道、水电站地下厂房等)涉及的不同地应力环境对围岩稳定的控制作用,通过对四川盆地普遍分布的侏罗系红砂岩三轴试验研究,系统分析了红砂岩在三轴加载和卸载应力条件下的变形破坏特征以及强度特性,揭示了红砂岩在不同应力路径下所表现出来的破坏方式以及性质差异,表明加载应力环境下以剪切破坏为主、卸载应力环境下则以拉裂破坏为特点,且前者的破裂角要明显大于后者。同时还明显表现出相同岩石在加、卸载应力环境下强度参数的差异,从强度参数看,红砂岩内聚力C值表现为卸载比加载条件下小,而内摩擦角φ值则刚好相反,表现为卸载比加载条件下大。以高围压(20MPa)卸载下所得强度参数为例,表明卸荷破坏下C值比加载条件下降低22.8%,而φ值比加载条件下提高57.2%,上述数据说明应力环境不同岩石强度参数差异明显,卸荷所导致的岩石强度参数弱化效应非常显著。According to a large number of underground engineerings （tunnels and underground power houses e. g. ） involved in geo-stress level controlling the stability of surrounding rock, through triaxial test of red sandstone in Jurassic, the paper analyses on the deformation and failure characteristics of red sandstone under different conditions by triaxial loading and unloading, and reveals the damage modes and mechanical properties difference by different stress conditions. It is showed that sheafing failure is primary under loading condition and tension failure is primary under unloading condition; the strength parameter difference is obvious under loading and unloading condition. The value of cohesion C under unloading condition is less than that under loading condition, and friction angle φ under unloading condition is bigger than that under loading condition. For instance, the strength parameters under unloaded high pressure （20MPa） show that the value of cohesion C by unloading decreases 22.8 percent than loading condition ; φ increases 57.2 percent. The above results obviously show differences of strength parameters by different geo-stress environment, and the weakness of strength parameters caused by unloading is very significant.

关 键 词：红砂岩 应力环境 力学性质 破坏方式 

分 类 号：TU457[建筑科学—岩土工程]