软土隧道支护压力与稳定性下限有限元分析

隧道开挖面的支护压力计算和稳定性分析至今尚未有比较成熟和简便的计算方法,本文基于岩土塑性极限分析理论,在分析下限有限元方法中引入非线性Power-Law屈服准则,通过对屈服准则的线性化处理,得到平面应变条件下软土隧道开挖面支护压力计算的下限有限元线性规划模型,编制了相应的Matlab有限元计算程序。计算表明:与极限平衡理论和极限分析上限有限元得到的结果比较,可以说明引入非线性Power-Law屈服准则的塑性极限分析下限有限元对隧道开挖面支护压力的计算和稳定性的分析是适用的。同时,总结了隧道埋深系数、土体重度系数等对隧道开挖面支护压力与稳定性的影响。

Study on Support Pressure and Stability of the Tunnel Face by Finite Element Lower Bound Limit Method

At present, the methods for support pressure calculations and the stability analysis of the tunnel face are not convenient and simple yet. In this paper, based on the geotechnical plastic limit analysis theory, the non-linear Power-Law yield criterion is introduced in the Geotechnical finite element plastic lower bound limit analysis method,and the Finite Element Lower Bound linear programming model under the plane strain condition is obtained by linear processing yield criterion, for the support pressure calculations of the tunnel face, the corresponding Matlab code is programmed. The results indicate that the geotechnical plastic limit analysis theory of the non-linear Power-Law yield criterion is also applicable in support pressure calculations and stability analysis of the tunnel face, compared with the results obtained by optimization theory and the upper bound limit method. The effect on the tunnel support pressure and the stability of tunnel face soils by tunnel depth factor, soil weight coefficient are summarized.