浅土层中隧道开挖的上限解模型

Upper bound solution model of tunnel excavation in shallow soil layer

根据极限分析理论上限原理,基于Davis等人提出的隧道垮落模型,提出了剪切区参数α=0时的新的隧道垮落模型。由不可压缩性条件求出了剪切区速度和间断线表达式,推导了此模型中间断线上能量消散,剪切区能量消散和总外力所做的功。利用能量守恒原理,求出了衡量隧道稳定的参数———稳定率表达式。此表达式可以更加合理的求解开挖隧道临界垮落载荷,为衡量隧道稳定提供理论依据。

Base on Davis et al tunnel failing model and the principle of the upper bound theory of plastic limit analysis,a new parameter α=0 governing size of shear zone of tunnel failing model was put forward.The velocity of shear zone and formula of line of discontinuity was applied in using incompressibility condition,deducing energy dissipated on the line of discontinuity, energy dissipated within shear zone and total the work done by the outside force of the model.A normal parameter which was usually used to govern size of stability ratio in the soil mechanics,that is,a formula of tunnel ration was obtained by applying conversation of energy theory.The loads of tunnel critical failing model are taken into account in the formula reasonably,which is also the important theory to identify tunnel stability.