高应力硬脆玄武岩微裂隙分布及破裂发展辨识  

Microfracture distribution and fracture development characteristics of high stress hard-brittle basalt

作　　者：陈平志 陈建林 王成虎[3] 刘宁 褚卫江 CHEN Pingzhi;CHEN Jianlin;WANG Chenghu;LIU Ning;CHU Weijiang(Power China Huadong Engineering Corporation limited,Hangzhou 311122,China;Hydro China Itasca Research and Development Center,Hangzhou 310014,China;The Institute of Crustal Dynamics,CEA,Beijing 100096,China)

机构地区：[1]中国电建集团华东勘测设计研究院有限公司,浙江杭州311122 [2]浙江中科依泰斯卡岩石工程研发有限公司,浙江杭州310014 [3]中国地震局地壳应力研究所,北京100096

出　　处：《人民长江》2020年第2期153-159,共7页Yangtze River

基　　金：国家自然科学基金资助项目(U1865203)。

摘　　要：白鹤滩水电站区域构造地应力高,玄武岩坚硬性脆、隐微裂隙发育,地下厂房开挖过程顶拱浅层应力型开裂和深层破裂特征明显,传统的声波、钻孔电视测试和变形监测等方法难以精确获取岩体微破裂裂隙分布特征及高应力破裂发展特征信息。采用高精度超声波成像综合测试系统新方法,对厂房顶拱应力破裂破坏显著区域进行了多次重复测试。测试成果揭示:①厂房顶拱上方岩体赋存的裂隙面倾角以陡倾角为主,优势倾角范围为45.98°~52.06°;裂隙面的倾向为NWW向,优势倾向范围为276.36°~292.01°,裂隙面倾角和倾向随深度变化不明显。②顶拱浅层围岩破裂裂纹集中区一般在3.50~4.25 m的深度范围内,围岩深部诱发破裂裂纹区主要分布在9.68~10.11,16.12~16.32,21.45~21.77 m范围。③局部岩体受顶拱应力场不断调整演化作用,出现岩体破裂随时间加剧的现象。该成果高精度地辨识了玄武岩不同深度微破裂裂隙面分布特征、深度范围和应力破裂发展特点,对研究高应力硬脆玄武岩力学特性和响应机理提供了坚实基础资料,为工程开挖施工和动态支护设计发挥了重要支撑作用。Baihetan Hydropower Station project lies in the area with high structural stress, where the brittle basalt has many hidden micro-fissures. Obvious stress-type cracking and deep-seated cracking were found in the top arch during excavation of the underground powerhouse. It is difficult to accurately acquire the distribution characteristics of micro-fracture and the development characteristics of high-stress cracking in rock mass by traditional methods such as acoustic wave, borehole television testing and deformation monitoring. In this paper, a new method of comprehensive testing system of high precision ultrasonic imaging is used. The results show that:(1) the inclination of fracture surface in rock mass above roof arch is mainly steep inclination, with dominant inclination range of 45.98°~52.06°, the strike direction is NWW with dominant direction of 276.36°~ 292.01°. The inclination angle strike does not change obviously with the depth.(2) The crack concentration area in the shallow roof arch is generally within the depth of 3.50~4.25 m. The induced crack areas in the deep rock mainly distribute in the range of 9.68~10.11 m, 16.12~16.32 m and 21.45~21.77 m.(3) The local rock mass is constantly adjusted under evolution of the stress field of the top arch, that the rock mass rupture increases with time. The research results provide basic data for the study on mechanical characteristics and response mechanism of high-stress hard-brittle basalt.

关 键 词：硬脆玄武岩 微裂隙分布与发展 高应力 高精度超声波 白鹤滩水电站 

分 类 号：P642[天文地球—工程地质学]