堆石料Gudehus-Bauer亚塑性本构模型改进及参数确定方法

研究了Gudehus-Bauer亚塑性本构模型和模型参数的求取方法。采用侧限压缩试验曲线求取模型参数颗粒硬度hs和指数n。根据模型方程的推导，建立了拟合指数 和 与围压之间的关系，并提出了新的拟合参数。考虑到堆石料具有明显的剪胀、剪缩性，在Gudehus-Bauer模型线性项中增加了主要控制体积应变项 ，以改善模型对堆石料体积应变曲线的描述。采用堆石料大型侧限压缩试验、常规三轴试验分别验证了新的拟合参数和改进后的Gudehus-Bauer亚塑性本构模型。与堆石料试验成果比较，提出的新拟合参数与改进后的Gudehus-Bauer亚塑性本构模型可以较好地模拟堆石料的应力-应变特性，并较好地改善了堆石料体变曲线的模拟结果。对改进后的模型作了常规三轴加、卸载模拟，模拟结果反映了改进的Gudehus-Bauer亚塑性本构模型具有一定的卸载适应性。

Improvement of Gudehus-Bauer hypoplastic constitutive model for rockfill materials and the determination of model parameters

Gudehus-Bauer hypoplastic constitutive model and the determination of its parameters are studied in the paper. Confined compression test is used to determine the parameters hs and n of hypoplastic constitutive model for rockfill materials. According to the derivation of the model, the relationships between the parameters , and the confining pressure are established, and new fitting parameters are proposed. Considering the dilatancy for rockfill materials, a new term of volumetric strain is added into the linear term in the model with a good fit to the axial strain-volumetric stain curve of triaxial consolidated drained tests. The new parameters of the model and the improvement on Gudehus-Bauer hypoplastic constitutive model are verified by means of rockfill large-scale confined compression test and triaxial consolidated drained tests. Compared with the test results of rockfill materials, the present model and its parameters can simulate the stress-strain characteristics of rockfill materials, and can improve the simulated axial strain-volumetric stain curve. Finally, the simulation to the triaxial consolidated drained test in loading-unloading condition by the improved Gudehus-Bauer hypoplastic constitutive model is carried out, and the results show that the improved model has a certain application of unloading.