The excavation of soft rock tunnel in fractured fracture zone often causes large deformation of surrounding rock . To analyze the construction deformation in fault zone and broken rock tunnel ,numerical simulation method is adopted to investigate the step method ,core indigenous reserve and three step construction method of surrounding rock deformation and ground subsidence .The results show that the fault fracture zone construction of tunnel surrounding rock deformation tends to be stable with increasing load step ,method of vault settlement value is large ,the three step method and core in-digenous reserve can better control the tunnel vault settlement ;convergence surrounding values with increasing load step stable ,step method of peripheral convergence maximum and three step method of peripheral convergence minimum ;sur-face subsidence has gradually reached a steady state with the increase of load step , the maximum ground settlement caused by construction of the three step method .The second step ,core indigenous reserve surface subsidence control ef-fect best ,reservation core soil above the tunnel transverse settlement trough was formed ,and with the increase of loading step ,the settlement tends to be obvious and finally reaches stability .%为研究断层破碎带隧道施工围岩变形规律,采用数值模拟方法分别考查了台阶法、预留核心土法和三台阶法施工时围岩变形及地表沉降情况.结果表明:断层破碎带隧道施工围岩变形量随着荷载步增加趋于稳定,台阶法造成的拱顶沉降值较大,三台阶法和预留核心土法能较好的控制隧道拱顶沉降;隧道周边收敛值也随荷载步增加逐渐稳定,台阶法周边收敛值最大、三台阶法周边收敛值最小;地表沉降随荷载步增加逐渐达到稳定,台阶法施工造成的地表沉降最明显,三台阶法次之,预留核心土法地表沉降控制效果最好;预留核心土法隧道上方横向形成明显的沉降槽,随着荷载步增加沉降槽趋于明显,最终达到稳定.
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