摘要
The commonly used Mohr-Coulomb(M-C) failure condition has a limitation that it overestimates the tensile strength of cohesive soils. To overcome this limitation, the tensile strength cut-off was applied where the predicted tensile strength is reduced or eliminated. This work then presented a kinematical approach to evaluate the active earth pressure on subgrade retaining walls in cohesive backfills with saturated seepage effects. An effective rotational failure mechanism was constructed assuming an associative flow rule. The impact of seepage forces, whose distribution is described by a closed-form solution, was incorporated into the analysis. The thrust of active earth pressure was derived from the energy conservation equation, and an optimization program was then coded to obtain the most critical solution. Several sets of charts were produced to perform a parameter analysis. The results show that taking soil cohesion into account has a distinct beneficial influence on the stability of retaining walls, while seepage forces have an adverse effect. The active earth pressure increases when tensile strength cut-off is considered, and this increment is more noticeable under larger cohesion.
用于表征土体强度的莫尔-库仑破坏准则的局限性在于它高估了大多数土体的抗拉强度。为了克服不足,本文采用抗拉强度截断概念对莫尔-库仑破坏准则进行了修正,降低或消除土体中的抗拉强度。在此基础上,基于极限分析上限定理,建立了在饱和渗流作用下回填黏土路基挡土墙的主动土压力计算模型。根据关联流动规则,构造了一个有效的旋转破坏模式,并将饱和渗流引入到破坏模式中,根据能量守恒方程,推导了主动土压力合力的显式表达式。借助最优化程序获得了目标函数的最优上限解,同时给出了一系列图以便工程应用。结果表明,土体黏聚力显著有利于挡土墙的稳定性,而渗流力则具有不利影响。考虑土体抗拉强度截断会明显降低主动土压力,特别是在黏聚力较大的情况下,其抗拉强度截断效果更为明显。
作者
FU He-lin
WANG Cheng-yang
LI Huan
傅鹤林;王成洋;李寰(School of Civil Engineering,Central South University,Changsha 410075,China;Department of Architecture and Civil Engineering,City University of Hongkong,Hongkong 999077,China)
基金
Projects(51538009,51674115,51804113) supported by the National Natural Science Foundation of China。
