沈阳圆砾土的扰动状态修正本构模型研究

Research on modified constitutive model of Shenyang circular-gravel based on disturbed state

对沈阳圆砾土进行三轴固结排水剪切试验;基于扰动状态理论,采用相对密实度Dr为扰动参量,提出统一扰动度函数,将其引入D-C模型中,提出适用于沈阳圆砾的修正D-C。试验结果表明,中密或密实状态圆砾土的应力-应变关系呈应变软化型,峰值强度随Dr的增大而增大,传统D-C模型中的参数K和峰值强度受扰动影响程度较大。采用作者提出的考虑扰动影响的修正模型计算结果较传统D-C模型更接近于真实的试验结果,该修正模型能更好地模拟沈阳圆砾土的强度与变形特性。

The triaxial consolidation drained shear tests were done on the circular-gravel in Shenyang region under different confining pressure. Based on the theory of DSC,the general disturbance function which can identify the influence of both the advantage disturbance and the disadvantage disturbance is established. Dr is used as a parameter of disturbance. Combine with the results of triaxial tests,the non-linear plastic constitutive model focused on the circular-gravel is obtained. The disturbance function is introduced into the traditional Duncan-Chang model. Meanwhile,the calculation curves by the modified model are analyzed comparing with the test curves. The results show that the modified model is better in considering the influence of disturbance comparing with the traditional models. The new model can make a better description of the strength and the deformation characteristics of the coarse-grained sand in Shenyang area.