深埋黄土隧道初期支护破坏模式研究

Research on the Failure Modes of Initial Support for Deep-buried Tunnel in Loess

研究目的:分析初支结构在施工过程中的破坏模式,对于研究深埋黄土隧道初支的受力机理以及优化隧道设计具有重要意义。本文以蒙华铁路阳山隧道工程为依托,通过水文地质情况、围岩压力、格栅应力等方面的分析,结合施工过程中初支结构的破坏情况,从而获得深埋黄土隧道初支结构的破坏模式。研究结论:(1)受老黄土节理发育影响,深埋隧道开挖过程中围岩容易产生较大的拱顶沉降,对初支结构造成的压力较大;(2)地表水的渗透会弱化老黄土节理面之间的强度,对围岩稳定性影响较大;(3)初支结构在拱肩部位的轴力值和弯矩值较其他位置偏大,容易发生小偏心受压的脆性破坏;(4)本研究成果可为深埋黄土隧道初支的受力机理研究和工程设计提供参考。

Research purposes： Analyzing the failure mode of the primary support structure in construction is of great significance to the study of the mechanical mechanism of the primary support of deep-buried loess tunnel and the optimization of tunnel design. Damage state of initial support in construction is analyzed,based on Yangshan tunnel of west Inner Mongolia to Central China railway. Further research on failure mode of initial support of deep-buried tunnel in loess is obtained from hydrogeological condition,surrounding rock pressure,and geogrids stress.Research conclusions：（ 1） Joints development in old loess during the excavation of tunnel produces large vault settlement,which increases the pressure of surrounding rock on initial supports.（ 2） The permeability of surface water will weaken the strength between the old loess joints and have a greater impact on the stability of surrounding rocks.（ 3） Shoulder part of the initial support sustains larger axial force and bending moment than the other parts,which leads to small eccentric compression damage and brittle failure.（ 4） The research results can provide a reference for the study of mechanical mechanism and engineering design of the initial support of deep-buried loess tunnel.