非饱和岩土体中浅埋隧道稳定性的极限分析

Upper bound stability analysis of shallow buried tunnels in unsaturated soils

自然土体大部分处于非饱和状态,而现有的隧道稳定性分析却假定土体是饱和的。为了研究土体的非饱和特性对隧道的影响,对非饱和土中浅埋隧道的稳定性进行了极限分析。基于非饱和土的Mohr-Coulomb强度准则和构建的浅埋隧道破坏机制,推导了围岩压力解析解。采用数值优化方法,计算了围岩压力的上限解。参数分析结果表明:基质吸力及埋深的增加有利于隧道的稳定,而地下水的存在不利于隧道稳定。

Natural soil deposits are normally unsaturated, while existing researches on tunnel stability regard soil masses as saturated. In order to investigate the impact of soil＇s unsaturated property on tunnel, limit analysis of stability of shallow buried tunnels in unsaturated soils is conducted. Based on the Mohr-Coulomb failure criterion for unsaturated soils and the constructed failure mechanism of shallow tunnels, the analytical solution of supporting pressure is deduced. Upper bound solution of supporting pressure is then obtained through numerical optimization. Conclusions of parameter analysis shows that matrix suction and the creasing burial depth are available to the stability of tunnel, but underground water is unavailable.