考虑围压对粗粒土蠕变特性影响的Burgers模型参数修正方法研究

传统的Burgers模型假设只有偏应力引起蠕变，而没有考虑围压对蠕变特性的影响，因此其主要用于描述岩石的蠕变特性。但不同于岩石，堆石料等粗粒土是由颗粒集合而成的摩擦型材料，其蠕变特性与围压密切相关。为了考虑围压对粗粒土蠕变特性的影响，该文首先推导了Burgers模型的三轴蠕变理论解，并根据各参数物理意义，提出一套简便实用的参数反演方法，用于获取同一围压不同偏应力下粗粒土的Burgers模型参数；进而总结并分析不同粗粒土的三轴蠕变实验结果，发现幂函数能较好地描述Burgers模型各参数随围压变化的规律；在此基础上，提出考虑围压对粗粒土蠕变特性影响的Burgers模型参数修正方法，并通过三组粗粒土的蠕变实验结果验证了所提方法的有效性。

PARAMETER CORRECTION METHOD OF BURGERS MODEL FOR COARSE-GRAINED SOIL CONSIDERING CONFINING PRESSURE

Based on the hypothesis that only deviatoric stress causes creep deformation, conventional Burgers model is not proper for the creep properties considering the influence of confining pressure. It is mainly used to characterize the creep behavior law of rock. Obviously different from rock, coarse-grained soil is a granular material, whose creep properties are closely related to confining pressure. To describe the creep behavior of coarse-grained soil considering the influence of confining pressure, a three-dimensional creep theoretical solution is derived firstly. Based on this solution, a practical parameter inversion method is presented to obtain the Burgers model parameters of coarse-grained soil under the same confining pressure but different deviatoric stress. Secondly, lab triaxial creep tests are summarized, and the power function is found felicitous to characterize the variation law between confining pressure and Burgers model parameters. Based on this, a parameter correction method of Burgers model is proposed to describe creep properties of coarse-grained soil considering the influence of confining pressure. Finally, three creep tests of coarse-grained soil are presented to demonstrate the validity of the proposed method.