锦屏二级引水隧洞大理岩强度参数研究  

Research on Marble Loading and Unloading Tests and Rheological Tests Strength Parameters from Diversion Tunnel of Jinping II Project

作　　者：刘晓燕[1] 曾海钊[2] 何江达[1] 谢红强[1] 

机构地区：[1]四川大学水利水电学院,成都610065 [2]中国水电顾问集团成都勘测设计研究院,成都610072

出　　处：《中国农村水利水电》2013年第5期157-160,167,共5页China Rural Water and Hydropower

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：高应力环境下,岩体加载强度和卸载强度差别很大,岩体的强度参数是工程设计中很重要的参数。锦屏二级引水隧洞最高地应力达70MPa,对锦屏二级水电站引水隧洞取得的埋深2 000m左右的大理岩岩样进行单轴和三轴常规试验、卸荷试验、蠕变试验,试验围压最高值达到80 MPa。试验结果表明:岩石属于硬脆岩石;大理岩围压效应明显,加载和卸载试验峰值强度随着围压增加而增加;相比常规三轴加载试验卸荷试验岩体黏聚力c值降低约42.9%,内摩擦角增加约70.2%;岩体的流变属性为"弹-粘弹-粘塑性",其流变力学模型可用西原模型来表征;流变长期强度凝聚力为0,内摩擦角为36.75.这些结论揭示高应力条件下大理岩的加卸载强度和长期强度,为引水隧洞开挖和支护长期稳定分析提供可靠依据。The characteristics of the rock mass in the loading and unloading of mechanics are essentially different geostress condttlons. Jinping II Hydropower Project diversion tunnels maximum stress reaches up to 70 MPa. A series of uniaxial tests and triaxial tests under loading and unloading conditions and creep tests are done on the marble samples from diversion tunnels of the Jinping II Hy- dropower Project depth of 2 000 m, the highest confining pressure reaches up to 80 MPa is greater than the actual maximum ground stress in test. The test results show that： the rock belongs to hard rock~ marble confining pressure is affected significantly. Peak strength increases with the increase in confining pressure in loading and unloading tests＇ in pre-peak unloading confining pressure tests, the cohesion c value decreases by about 42. 9% and internal friction angle increases by approximately 70. 20%. Compared to conventional triaxial compression test, the theological properties of the rock mass are referred to as ＂bombs - visco-elastic -- visco- plastic＂, so the Nishihara model can be used to characterize the rheological models. These conclusions reveal the mechanical proper- ties of marble under high in-situ stress and provides a reliable basis for excavation diversion tunnels stability analysis.

关 键 词：岩石力学 高地应力 力学试验 强度参数 

分 类 号：TV223.1[水利工程—水工结构工程]