双剪统一强度准则修正及土压力计算

Amendment of the twin-shear criterion and its application to calculation of earth pressure

提出了主剪面应力对和主剪面应力对的作用这两个新概念,并以此为出发点,通过考虑十二面体单元主剪面上所有三个主剪面应力对的共同作用,在双剪统一强度准则的基础上提出了一个新准则,并对其作了极限线分析、应力莫尔圆分析、中间主应力效应曲线分析和破坏角分析。研究表明,该准则能非线性地反映岩土的基本强度特征。同时,也不存在双剪强度准则中的双重破坏角问题。最后,还应用新强度准则分析了土压力计算问题。

In this paper, two new terms of the stress couples acting on the principal shear planes and their actions are proposed and a new failure criterion is given to amend the twin-shear unified failure criterion based on the considerations that the effects of all the three stress couples acting on the principal shear planes of the dodecahedral element should be taken into account in the establishment of the failure criterion. Theoretical analyses of the loci on π plane and the loci on (σ1 - σ2 ) plane, the Mohr circles on (σ - τ) plane, the effective curves with the intermediates principal stress, and the directions of the failure surface have shown that this criterion can basically reflect the nonlinear failure and strength characteristics of the geomaterials and avoid the defect of two broken angles existed in the twin-shear unified criterion under some stress states. Finally, this new criterion is used to analyze the earth pressure of retaining wall.