二次曲线作为Mohr包线时的地基塑性区

Determination of critical edge pressure and plastic zone for subsoil considering quadratic curve as mohr envelop

基于Mohr强度理论和三轴试验结果,建立了Mohr破坏包线的二次型形式。与直线型Mohr-Coulomb准则相比,该破坏模型能反映土体抗剪强度增长随正应力增加逐渐趋缓的特点。在此基础上,基于弹性理论并且抛弃K=1的假设导出了求解塑性区的方程,与塑性区的几何方程一起构成可以求解的方程组。算例分析结果表明,由本法确定的结果有以下特点:临塑荷载较小且塑性区的形状和发展趋势也不同于传统法得出的结论。

A quadratic curve is built as Mohr envelop based on Mohr＇s strength theory and results of triaxial tests. The proposed failure criterion can reflect nonlinear trend of increment of soil＇ s shear strength with normal stress. Then, based on elastic theory and that lateral force coefficient is not equal to unit, formulae are constructed to determine the plastic zone. When coupled with geometric equation for plastic zone figure, solution can be attained by the digital approximation method. Compared with the traditional method, critical load given by the proposed method is smaller and the shape and development trend of the plastic zone is not similar either.