土体非线性模型的分段切线模量研究

Segmented tangent modulus of nonlinear soil model

结合大量实验数据，基于原邓肯非线性模型，建立了土体达到抗剪强度之前分段切线模量的非线性模型，其轴向应变εa与轴向压应力（σ1-σ3）的比σa／（σ1-σ3）-εa曲线包括向上弯折和向下弯折2种，均由两折线组成．硬化型曲线一般可用向下弯折的折线进行拟合，而软化型且剪胀比较明显的应力-应变关系用向上弯折的折线进行拟合．试验结果表明，该模型较原邓肯非线性模型能更好地模拟土的应力、应变发展情况，与实际更加吻合．

A segmented tangent modulus model was developed based on a great deal of triaxial compression test data and Duncan＇s nonlinear model of soil. According to the model, there were two kinds of σa/（σ1-σ3）-εa curves of soil befor failure, i.e. upward bending curve and downward bending curve, and each kind of curves was divided into two parts according to their turning points. The curve for hardening soil was fitted with downward bending lines, while the stressstrain curve for softening soil with characteristic of dilatation was fitted with upward bending lines. Experimental result shows that the present model is better than Duncan＇ s nonlinear model in simulation of stress-strain curves of soil, and the simulated result is in good agreement with test data.