高地应力对结构面现场直剪试验的影响分析  

Influence of High Geostress on In-Situ Shear Test of Structural Plane

作　　者：陈学章[1] 何江达[1] 谢红强[1] 肖明砾[1] 

机构地区：[1]四川大学水利水电学院,四川成都610065

出　　处：《人民黄河》2014年第11期127-130,共4页Yellow River

基　　金：国家自然科学基金资助项目(51079092);四川省科技支撑计划项目(2008SZ0163)

摘　　要：抗剪强度参数是工程设计中的重要指标。结合锦屏二级水电站引水隧洞地应力测试及横观各向同性结构面的现场直剪试验,基于非线性有限元法,揭示高地应力及试验荷载作用下剪切应力分布规律,研究高地应力对结构面强度参数的影响。研究表明:现场直剪试件制备时,试验探硐围岩开挖卸荷将在试件预裂面上产生对称分布的正应力及剪应力;地应力释放将使直剪试件预裂面出现损伤破坏及细微裂纹,降低试件极限抗剪能力,引起抗剪强度参数的误差;反演分析表明,在考虑地应力释放情况下,结构面凝聚力可提高约11.65%。Shear strength parameter is an important indicator of the engineering design. Based on the field tests and stress tests of transversely iso-tropic structural plane from diversion tunnel of JinpingⅡproject,the nonlinear finite element was adopted to reveal the shear stress distribution un-der high geo-stress and test load conditions,and study the influence of high geo-stress on strength parameters. The results show that positive stress and shear stress distributed symmetrically on the pre-split face of structure plane specimen in the excavation unloading of test hole under specimen preparation of shear test. The release on high geo-stress will cause damage failure and micro cracks on the pre-split face of structural plane. And it will reduce the ultimate shear capacity of the specimen,causing errors of shear strength parameters testing. While the results of inversion analysis show that the cohesion force of the structural plane can be increased by 11. 65% under geo-stress released.

关 键 词：高地应力 结构面 强度参数 直剪试验 非线性有限元 

分 类 号：TV223.1[水利工程—水工结构工程]