Pastor-Zienkiewicz状态相关本构模型及其参数确定方法研究

Pastor-Zienkiewicz based constitutive model and determination method of its state parameters

当考虑无黏性土初始密实度及围压时,Pastor-Zienkiewicz本构模型需采用多组参数模拟同种材料,给其在实际中的应用带来了困难。针对原始Pastor-Zienkiewicz本构模型存在的这一问题,将新近发展的状态相关参数引入剪胀方程、塑性势方向矢量、加(卸)载方向矢量及塑性模量方程中,提高了模型在考虑初始密实度及初始围压时模拟无黏性土力学特性的能力;详细探讨了修正模型参数的拟定方法,明确了各参数的物理意义;通过试验资料对修正模型的预测能力进行了验证,预测结果与试验资料吻合良好,表明了修正模型的可行性和合理性。

When initial density and confining pressure of non-cohesive soil are considered in Pastor-Zienkiewicz（PZ） constitutive model, multiple sets of parameters are required to simulate the same type of material. Thus this model is pretty difficult to be applied in practice, which to a great extent limits its development. To solve the existing deficiency of the PZ model, some recently proposed state parameters are introduced into the dilatancy formula, plastic potential direction vector, loading（unloading） direction vectors and plastic modulus equation of the original PZ model, separately. It is found that the predicting capability of the modified model has been improved in terms of mechanical behaviour of the non-cohesive soil, particularly by considering the initial density and confining pressure. Then the calibrating method for each parameter in the modified model is discussed in detail and the physical meaning of each parameter is further clarified, according to a practical example. Finally, the predictive ability of the modified model is verified by the experimental data. It is shown that predicted results are in good agreement with experimental data, which indicates the modified model is reasonable and feasible.