川西郭达山隧道水平孔地应力测量与工程意义  

In-situ Stress Measurement of Guodashan Tunnel Horizontal Borehole in West Sichuan and the Engineering Significance

作　　者：孙炜锋[1,2] 郭长宝 张广泽[3] 张永双 徐正宣[3] 谭成轩 李丹[3] 王献礼[4,5] SUN Weifeng;GUO Changbao;ZHANG Guangze;ZHANG Yongshuang;XU Zhengxuan;TAN Chengxuan;LI Dan;WANG Xianli(Institute of Geomechanics,Chinese Academy of Geological Sciences,Beijing 100081,China;Key Laboratory of Neotectonic Movement and Geohazard,Ministry of Land and Resources,Beijing 100081,China;China Railway Eryuan Engineering Group Company Limited,Chengdu,Sichuan 610031,China;Institute of Hydrogeology and Environmental Geology,Chinese Academy of Geosciences,Shijiazhuang 050061,China;Sichuan Provincial Chuanjian Institute of Investigation and Design,Chengdu,Sichuan 610041,China)

机构地区：[1]中国地质科学院地质力学研究所,北京100081 [2]新构造运动与地质灾害重点实验室,北京100081 [3]中铁二院工程集团有限责任公司,四川成都610031 [4]中国地质科学院水文地质环境地质研究所,河北石家庄050061 [5]四川省川建勘察设计院,四川成都610041

出　　处：《现代地质》2021年第1期126-136,共11页Geoscience

基　　金：国家自然科学基金项目(41941017,41877279,41731287);中国地质调查局地质调查项目(DD20190319)。

摘　　要：新建川藏铁路穿越鲜水河活动构造带,沿线构造应力场极其复杂,隧道围岩工程破坏问题突出。为了揭示该区构造应力场特征,为深埋隧道设计、施工提供基础参数,采用新型水压致裂地应力测量系统在川西郭达山隧道水平孔获得10段有效地应力测量数据,最大测量深度达508.10 m,创造了水平孔地应力测量最深记录。测量结果表明,在148.4~508.1 m测量深度范围,郭达山隧道水平孔截面上最大主应力值为3.59~13.72 MPa,最小主应力值为3.28~8.36 MPa。根据印模实验结果,除浅部钻孔截面上最大主应力倾角较大外,深部钻孔截面上最大主应力倾角近水平。根据地应力状态将0~280 m段划分为应力释放区,280~330 m段为应力集中区,大于330 m段为原地应力区。基于地应力测量结果对郭达山隧道水平孔围岩稳定性进行了预判分析,在孔深292.9 m、508.10 m处隧道围岩有轻微至中等程度岩爆可能,其余段无岩爆可能性。The newly built Sichuan-Tibet railway line extends across the Xianshuihe active tectonic zone,along which the tectonic stress field is extremely complex,and the risk of tunnel rock engineering failure is prominent.To reveal the local tectonic stress-field,to provide basic parameters for deep-buried tunnel design and construction,and by using the recently-developed hydraulic fracturing in-situ stress measurement instrument,a total of 10 valid in-situ stress data were obtained from the Guodashan tunnel horizontal borehole(maximum borehole depth:508.10 m),creating a new record of hydraulic fracturing in-situ stress measurement in horizontal borehole.Our results show that at the borehole depth of 148.4 to 508.10 m,the maximum principal stress is 3.59-13.72 MPa,whilst the minimum principal stress is 3.28-8.36 MPa along the borehole section plane.According to the fracture impression results,the dip of the maximum principal stress along the borehole section plane is approximately horizontal in the deep part of the borehole,except for the shallow part of the borehole where the maximum principal stress is steep.According to the in-situ stress state of the horizontal borehole,we located the stress-releasing zone at 0 to 280 m depth,the stress-concentration zone at 280 to 330 m,and the undisturbed-stress zone at above 330 m depth.Based on the in-situ stress measurement results,wallrock stability of the Guodashan tunnel was analyzed.The analysis reveals that the wallrocks would experience slight to moderate rockburst at only 292.9 m and 508.10 m depth.

关 键 词：水平孔 水压致裂 原地应力测量 深埋隧道 岩爆 

分 类 号：P554[天文地球—构造地质学] P642[天文地球—地质学]