非线性破坏准则下被动土压力的计算

Calculation of passive earth pressure with nonlinear failure criterion

基于采用非线性Mohr-Coulomb破坏准则,提出一个对刚性挡土墙的墙后被动土压力计算方法,分析和确定了滑动面的位置以及此时被动土压力的大小。首先,应用"切线法"引入了变量Ct和tφ,然后运用迭代法计算得出对应于不同潜在滑动面上的Ct和φt,再运用广义库仑土压力理论求解被动土压力。其中对应于最大被动土压力的滑动面即为最危险滑动面,此时的被动土压力即为所求。通过与采用线性Mohr-Coulomb破坏准则下的研究比较得出,采用线性Mohr-Coulomb破坏准则计算的被动土压力结果偏大,在实际工程设计中偏于不安全,而采用非线性Mohr-Coulomb破坏准则在确定刚性挡土墙的墙后被动土压力时更加符合实际工程,结果更加准确。

Based on the Mohr- Coulomb nonlinear failure criterion, a method was suggested, which converts the calculating of the passive earth pressure behind a rigid retaining wall, was employed to determine the position of slip surface and active earth pressure. Firstly, variable Ct and φt were created by tangents method, then Ct and φt corresponded to each different potential slip surfaces were calculated by iteration method, then using generalized Coulomb soil pressure theory to obtain passive earth pressure. The one that has the maximum passive earth pressure should be the most dangerous slip surface, and the maximum passive earth pressure is also desired. After comparing with the research resuits by using Mohr - Coulomb linear failure criterion, adopting the Mohr - Coulomb linear failure criterion can provide a higher passive earth pressure value, and causing insecurity factor in real project, while adopting the Mohr - Coulomb nonlinear failure criterion can provide more practical and accurate results when calculating the passive earth pressure behind the rigid retaining walls.