Mohr包线的二次曲线形式

Study on conic for Mohr curve

为了研究岩土类材料破坏的非线性,基于直剪试验和三轴试验结果的特点建立了二次抛物线形式的Molar破坏包线,并给出了主应力表达形式。与Mohr-Coulomb准则一样,确定此破坏包线只需要两个破坏Mohr圆。根据本法得到的偏平面上的屈服迹线呈等边不等角曲边六边形,且随平均主应力增大,屈服迹线相对于由Mohr-Coulomb准则得到的结果要经历三个阶段:小于Mohr-Coulomb 准则屈服迹线、大于Mohr-Coulomb准则屈服迹线和小于而且越来越小于Mohr-Coulomb准则屈服迹线。利用本模型在子午面上可以方便地直接给出平均主应力与偏剪应力的关系。本模型可以反映拉压不等性。

In order to research the non-linear damage of the kinds of the rock-soil material, based on results of direct and triaxial shear tests, a conic is established as Mohr yield curve and at the same time the formulas which illustrate the yield surfaces in primary stresses space are given too. Only two yield Mohr circles are needed for determining the curve just as for Mohr-Coulomb criterion. According to the proposed model, the yield curves on deviatoric plane are un-conformal curve hexagons and will undergo three phases which are smaller, larger and smaller than the yield curves got by Mohr-Coulomb criterion when hydraulic static pressure rises continuously from a negative value to a big positive one. Relationship between average principal stress and deviatoric shear stress can be obtained easily and directly with this model. The model can reflect the difference of soil＇s strength between pull and press stress states.