基于扰动理论的沈阳中粗砂本构模型

针对沈阳地区中粗砂在不同围压下的三轴固结排水剪切试验,发现中粗砂的相对密实度对其强度和变形特性有重要影响.以相对密实度为自变量,提出了统一扰动度函数.基于试验数据,建立了统一扰动度与初始模量和峰值强度的函数关系,提出考虑扰动的D-C模型.将其预测结果与D-C模型预测结果及试验结果进行对比:D-C模型的预测值在D_D接近0时与试验结果比较一致;土体受到正扰动时,D-C模型预测的应力值较该修正模型偏大;而土体受到负扰动时,其预测的应力值又相对偏小,因此考虑扰动的D-C模型能更好地模拟沈阳地区中粗砂的强度及变形特性.

Constitutive Model of Shenyang Medium-Coarse Sand Based on Disturbance Theory

The results of triaxial consolidation drained shear tests on medium-coarse sand in Shenyang region under different confining pressures show that the relative density strongly affects the strength-deformation property of medium-coarse sand.Taking the relative density as independent variables， the general disturbance function was put forward. Then the modified D-C model， which could reflect the disturbance’s influence on the strength-deformation property of medium-coarse sand， was developed by establishing the relationship between parameters K and peak strength and disturbed degree. The contrasts of the forecast results between the modified D-C model and D-C model are as follow: the forecast results of D-C model and experimental results are consistent when D_○D is close to zero; the stress value predicted by D-C model is larger than the modified model in this paper when sand is positive disturbance; the stress value predicted by D-C model is smaller than the correction model when sand is negative disturbance. It is found that the modified D-C model can describe the strength-deformation property of medium-coarse sand better than D-C model at the disturbed state.