基于应力多边形与钻孔崩落的白鹤滩右岸厂房区地应力场特征研究  

Characteristics of in-situ stress field in the powerhouse area on the right bank of Baihetan based on stress polygon and borehole breakout method

作　　者：陈念 王成虎 高桂云 王璞 CHEN Nian;WANG Cheng-hu;GAO Gui-yun;WANG Pu(National Institute of Natural Hazards,Ministry of Emergency Management of the People’s Republic of China,Beijing 100085,China;School of Civil Engineering,Tianjin University,Tianjin 300354,China)

机构地区：[1]应急管理部国家自然灾害防治研究院,北京100085 [2]天津大学建筑工程学院,天津300354

出　　处：《岩土力学》2021年第12期3376-3384,共9页Rock and Soil Mechanics

基　　金：国家自然科学基金面上项目(No.41574088)。

摘　　要：白鹤滩水电站是我国能源布局西电东送的骨干能源点。在水电站建设初期使用常规方法获得了一些地应力场数据,但随着地下厂房硐室开挖,出现了显著的高应力作用导致的脆性破坏。因此,开展开挖过程中的地下厂房围岩地应力场的研究对未来地下厂房的长期稳定性具有重要意义。利用高精度超声波井下电视成像系统对钻孔井壁进行扫描获取录井图像,使用Well CAD软件提取钻孔崩落宽度WBO,将基于Mohr-Coulomb摩擦准则以及Anderson断层理论形成的应力多边形法与基于修正Wiebols-Cook岩石强度准则的钻孔崩落法相结合,对应力量值进行限定估算,从而计算出工程区岩体应力场特征。研究结果显示工程区水平最大主应力方向为N30.15°E,水平最小主应力S_(h)、垂直主应力S_(V)、水平最大主应力S_(H)量值分别为11.62±0.34MPa、14.45±0.33MPa、25.88±5.61MPa,测试段应力量值大小关系为S_(h)<S_(V)<S_(H),应力结构类型为走滑断层型。对比分析表明,应力多边形与钻孔崩落法联合限定工程岩体应力场特征具有较高的准确性,为认识水电工程区应力场特征提供了一条可行的路径。The Baihetan hydropower plant is one of the most important backbone energy points of power transmission from west to east in China’s energy layout.In the initial stage of hydropower plant construction,some in-situ stress data were obtained by using conventional methods.However,with the continuous excavation of underground cavern,significant brittle failures caused by high stresses were observed in the surrounding rock.Therefore,the study on the stress field of surrounding rock mass is highly important for the long-term stability control of underground caverns.The borehole wall was scanned by the high-precision ultrasonic downhole television imaging system to obtain the logging image,and the widths of breakouts WBO was extracted by WellCAD software.The stress polygon based on Mohr-Coulomb criterion and Anderson theory and the breakout failure method based on Wiebols-Cook criterion were integrated and utilized to limit the estimation of stresses value,the characteristics of rock mass stress field in the project area were analyzed.The results show that the orientation of the maximum horizontal principal stresses in the engineering area was about N30.15°E,and the magnitudes of the major principal stresses were S_(h)=11.62±0.34 MPa(horizontal minimum principal stress),S_(V)=14.45±0.33 MPa(vertical principal stress),S_(H)=25.88±5.61 MPa(horizontal maximum principal stress) respectively.This stress state is favorable for the strike-slip faulting(S_(h)<S_(V)<S_(H)).The comparative analysis shows that the combination of stress polygon and borehole caving method has high accuracy,which provides a feasible way to understand the characteristics of stress field in hydropower project area.

关 键 词：白鹤滩水电站 超声波钻孔电视 应力多边形 钻孔崩落法 工程岩体应力场 

分 类 号：TU452[建筑科学—岩土工程]