硬岩开挖诱发扰动应力旋转规律及其对岩体破裂的影响  

Law of disturbed stress rotation induced by hard rock excavation and its influence on rock fracture

作　　者：孙钱程[1] 刘越 王庆文 李邵军[2] 郑民总 SUN Qian-cheng;LIU Yue;WANG Qing-wen;LI Shao-jun;ZHENG Min-zong(National Field Observation and Research Station of Landslides in Three Gorges Reservoir Area of Yangtze River,China Three Gorges University,Yichang,Hubei 443002,China;State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,Hubei 430071,China)

机构地区：[1]三峡大学湖北长江三峡滑坡国家野外科学观测研究站,湖北宜昌443002 [2]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,湖北武汉430071

出　　处：《岩土力学》2023年第11期3128-3140,共13页Rock and Soil Mechanics

基　　金：国家自然科学基金资助项目(No.51909136,No.42202320)。

摘　　要：针对深部地下工程扰动应力场变化诱发围岩损伤破裂的问题,在详细分析锦屏地下实验室Ⅱ期工程扰动应力场测试数据的基础上,解译了不同施工过程下扰动应力场的变化规律,分析了主应力方向的变化模式,通过对照分析岩体原位钻孔成像,揭示了主应力方向变化对围岩破裂的影响。研究结果表明:中导洞开挖阶段是扰动应力场变化最活跃的阶段,开挖掌子面向监测断面推进的过程中主应力方向的变化模式以应力回旋为主,开挖掌子面远离监测断面推进的过程中主应力方向的变化模式以应力旋转为主,主应力方向出现最大变化幅度的位置在距离边墙4.5 m测点处;边墙扩挖阶段,主应力方向的变化模式以应力旋转为主,主应力方向出现最大变化幅度的位置在距离边墙2.5 m测点处;扰动应力方向变化直接影响岩体裂隙发育的形态和走向,大角度旋转的应力容易诱发张拉裂隙以及拉-剪混合型裂隙,小角度旋转时更倾向于诱发破裂面偏转角度与应力旋转角度相当的、具有凹凸形态的剪切裂隙,大角度回旋的应力多形成相互交叉的“X”型剪切裂隙。基于实测扰动应力的研究结果可为深埋高应力硬岩开挖的扰动应力场变化规律及其对岩体破裂发展的影响研究提供参考。The rock fracture caused by disturbed stress field change in deep underground engineering is a common issue receiving continuous attention.After analyzing the test data of disturbed stress field in Jinping underground laboratory phase Ⅱ project,the variation law of disturbed stress field under different construction processes was interpreted,and the change mode of principal stress direction was analyzed.Through the comparative analysis about in-situ drilling imaging of rock mass,the influence of principal stress direction change on surrounding rock fracture was revealed.The results show that the disturbed stress field changes the most actively at the stage of middle drift excavation,the change mode of principal stress direction is mainly gyration when the tunnel face is advancing toward the monitoring section,and the change mode is mainly rotation when the tunnel face moves away from the monitoring section.The position where the principal stress direction change reaches the maximum is 4.5 meters away from the sidewall.During the expanded excavation of sidewall,the change mode of principal stress direction is mainly rotation,and the position where the change reaches the maximum is 2.5 meters away from the sidewall.The change in disturbed stress direction directly affects the pattern and trend of rock fracture development,the stress with large-angle rotation tends to cause tensile crack and tensile-shear mixed crack,and the stress with small-angle rotation tends to cause the shear crack with concave and convex morphological features whose deflection angle equals the stress rotation angle.The stress with large-angle gyration mostly causes X-shaped shear crack.The results based on the measured disturbed stress can provide a reference for studying the variation law of disturbed stress field during deep high-stress hard rock excavation and its influence on rock facture development.

关 键 词：深部岩体 硬岩开挖 扰动应力 应力方向 岩体破裂 

分 类 号：TU451[建筑科学—岩土工程]