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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。
The traditional Burgers model assumes that only deviatoric stress causes creep without considering the effect of confining pressure on the creep behavior, so it is mainly used to describe the creep characteristics of rocks. However, unlike rock, rockfill and other coarse-grained soil is a friction-type material composed of particles gathered, and its creep properties are closely related to confining pressure. In order to consider the effect of confining pressure on the creep characteristics of coarse grained soil, this paper first derives the Burgers model of the triaxial creep theory solution, and according to the physical meaning of each parameter, presents a simple and practical parameter inversion method for obtaining Burgers model parameters of coarse grained soil under the same confining pressure and different deviatoric stress are discussed. Then the triaxial creep experimental results of different coarse grained soils are summarized and analyzed. It is found that the power function can better describe the variation of Burgers model parameters with confining pressure. On this basis, a Burgers model parameter correction method considering the influence of confining pressure on the creep characteristics of coarse grained soil is proposed. The effectiveness of the proposed method is verified by the creep experiment results of three groups of coarse grained soils.