摘要
采用理论分析和数值模拟手段,开展跨度对围岩稳定性的影响规律研究。结果表明,在开挖后仅出现弹性二次应力状态条件下,单纯的增加隧道开挖跨度而不改变断面形状对围岩应力状态影响不大,但若开挖后形成塑性区,则即使不改变断面形状,单纯加大开挖跨度也会大大增加塑性区半径,影响围岩稳定。通过对乌蒙山2号四线铁路隧道深、浅埋工况毛洞破坏模式的对比分析,建议浅埋工况支护以刚度要求为主,减小释放,控制沉降,深埋工况支护以强度要求为主,适当释放,变形可控。
By means of theoretical analysis and numerical simulation, the influence of the span length on the surrounding rock stability was researched. The results indicate that if only the elastic secondary stresses occurred after the excavation, the influence on the surrounding rock stress state would be little by merely increasing the tunnel span length without changing the section shape. But if the plastic zone occurred after the excavation, and even if the section shape were not changed, the radius of the plastic zone would be increased by merely increasing the excavation span length, and consequently the surrounding rock stability would be weakened. Moreover, based on the example of Wumengshan No. 2 railway four-track tunnel, the comparative analysis of the failure modes of unlined tunnels was conducted between the deeply-buried case and the shallow-buried case. The result suggests that for the shallowly-buried case, the support system should be dominated by the rigidity requirements, so as to reduce the release and control the settlement; while for the deeply-buried case, the support system should be dominated by the strength requirement, with the appropriate releasing and controllable deformation.
出处
《铁道标准设计》
北大核心
2013年第10期93-96,共4页
Railway Standard Design
基金
铁道部科技研究开发计划项目(2010G016-H)
国家自然科学基金青年科学基金项目(51208437)
中央高校基本科研业务费专项资金(SWJTU11ZT33)
教育部创新团队发展计划资助(IRT0955)
关键词
铁路隧道
开挖跨度
围岩稳定性
数值模拟
四线铁路隧道
破坏模式
railway tunnel
excavation span length
stability of surrounding rock
numerical simulation
four-track railway tunnel
failure mode