正交隧道-滑坡体系层状岩体隧道变形破坏机理
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关键词：隧道-滑坡体系;层状岩体；隧道开裂变形；长持时降雨;遍布节理模型;强度折减法中图分类号：U25；P642.5 文献标志码：A 文章编号：1672-9315（2025）05-0954-10DOI：10. 13800/j. cnki. xakjdxxb.2025.0511
Deformation and failure mechanismsof layered rock mass tunnel in orthogonal tunnel-landslide system
JIANG Zhenwei， SHEN Bingyan， XING Weijian （School of Geological Engineering and Geomatics， Chang'an University，Xi’an 71Oo54， China）
Abstract： To elucidate the deformation and failure mechanisms of tunnels in layered rock masses under landslide influence，the Lueyang Nanshan tunnel-landslide system was studied.FLAC software was employed，and the strength reduction method was used to calculate landslide stability variations.Based on theubiquitous joint model，the bending moment distribution characteristics of the tunnel lining in the layered rock mass were calculated at diffrent stages of landslide stability change.The results show that： The overall stability factor of the Nanshan landslide was 1.25 before front excavation，1.17 after excavation，and1.O3 under prolonged rainfall conditions，indicating significant landslide stability changes; Anisotropic characteristics of layered rock induces pronounced eccentric compression in tunnel linings， with maximum bending moments occurring at mid-lower sections of mountain-side sidewalls， consistent with actual cracking patterns; The maximum bending moment of the tunnel lining was initially 67.7 kN m， increased to 70.0kN mafter front excavation，and reached 84.5kN m under prolonged rainfall conditions，demonstrating that the structural forces on the tunnel are closely related to landslide stability; Bedding characteristics influence the tunnel bending moment significantly.When bedding is horizontal or vertical，the bending momentsatvarious parts of the tunnelare relativelysmall and the distribution is more symmetrical. When the bedding dip angle is steep（ 45∘～75∘） and aligned with the slope direction，the maximum bending moment occurs in the mountain-side sidewall.The bedding orientation in the Nanshan tunnel-landslide system fals precisely within this extremely unfavorable range， resulting in tunnel deformation and cracking. These findings can provide a practical reference for the engineering design of similar tunnel-landslide systems.
Key words： tunnel-landslide system; layered rock; tunnel cracking and deformation; long-duration rainfall; ubiquitous-joint model; strength reduction method
0 引言
层状岩体是山区地下工程的常遇地层，由于岩层变形和强度的各向异性及层理面的低强度特征，围岩变形具有明显的非对称性，破坏模式有层间拉裂、层面滑移、弯曲破坏等，远较均质岩体复杂，具体破坏模式与层面产状、应力水平及地下工程的规模等因素密切相关[1-3]。（剩余15196字）
