摘要
跨断层隧道围岩性质会发生突变,给隧道施工扰动分析和安全预测带来了挑战。准确识别跨断层隧道在不同围岩条件下施工诱发的应力路径并开展基于应力路径的扰动分析,具有重要的科学价值和工程实践意义。因此,构建了基于围岩应力路径的隧道开挖扰动分析方法,通过三维数值分析识别了跨断层隧道施工诱发的典型应力路径并进行了扰动分析,总结了跨断层隧道施工扰动时空规律。结合围岩的强度准则和应力路径,用扰动系数描述扰动后围岩应力状态接近破坏的程度。随着扰动系数的增大,围岩应力状态逐渐接近破坏准则,当扰动系数等于1时,围岩发生破坏。跨断层隧道在上下盘围岩区的扰动系数始终小于1,处于弹性状态;而断层破碎区因围岩性质差,其开挖扰动系数达到1,进入塑性和破坏状态。离洞壁越远,施工扰动越小,扰动系数亦越小。支护后,断层破碎区和上下盘硬岩区的扰动系数均出现减小趋势,围岩趋于稳定,表明了支护的有效性。
The mechanical properties of rock changes abruptly at the fault, which poses challenges for the analysis of construction disturbance and safety prediction of tunnels across faults. It is of great scientific value and practical engineering significance to accurately identify the stress path induced by the construction of a tunnel across faults under different surrounding rock conditions and performing disturbance analysis based on the stress path. Therefore, this paper proposes a new analysis method of disturbance induced by the tunnel construction based on the stress path and identifies the typical stress path induced by the construction of a tunnel across a fault through three-dimensional numerical analysis. The disturbance analysis is finally performed and the results are summarized in terms of the timespace law of construction disturbance. By combining the strength criterion and stress path, the disturbance coefficient(DC) is defined to describe the relative distance between the stress state and the strength line. As DC increases, the stress state approaches the strength line. When DC=1, the rock reaches the failure state. For tunnels across faults, DC in the footwall or hanging wall is always less than 1, indicating its elastic state, while DC in the fault equals 1 after excavation due to its poor mechanical properties. DC deceases with the increase of distance to the cave. After the construction of lining, DC in both fault zone and footwall/hanging wall zone decrease, and the surrounding rock become more stable, demonstrating the effectiveness of the lining.
作者
乔亚飞
肖颖鸣
丁文其
何满潮
樊勇
QIAO Yafei;XIAO Yingming;DING Wenqi;HE Manchao;FAN Yong(Department of Geotechnical Engineering,College of Civil Engineering,Tongji University,Shanghai 200092,China;State Key Laboratory for Geomechanics and Deep Underground Engineering,China University of Mining&Technology,Beijing 100083,China;Yunnan Institute of Water&Hydropower Engineering Investigation,Design and Research,Kunming 650021,China)
出处
《防灾减灾工程学报》
CSCD
北大核心
2023年第1期50-59,共10页
Journal of Disaster Prevention and Mitigation Engineering
基金
国家自然科学基金(42007255,52090083)
滇中引水工程关键技术研究(2020)资助。
关键词
断层
隧道
施工扰动
应力路径
数值模拟
fault
tunnel
construction disturbance
stress path
numerical simulation
