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吕梁山花岗岩风化土与长江以南的花岗岩风化土具有较大差异。为了全面认识花岗岩风化土的力学性状,并为合理评价山区路基填料的工程性质提供依据,通过常规物理力学试验和大三轴试验,评价了吕梁山压实花岗岩风化土的基本物理特性和强度特性,发现所研究风化土在较低围压下即表现出颗粒破碎特性。参照既有研究成果,修正了花岗岩风化土峰值应力比M_f和状态应力比M_c的关系,确定了吕梁山压实花岗岩风化土的弹塑性本构模型。基于等向压缩-卸载试验与初始剪切的连续性假定,结合邓肯-张模型,最终获得了修正强度条件下风化土本构关系的所有模型参数。通过比较计算和试验结果,验证了峰值应力比与状态应力比的乘积为平均主应力的幂函数关系的合理性。
The Lvliangshan granite weathered soil is different from the granite weathered soil south of the Yangtze River. In order to fully understand the mechanical properties of granite weathering soil and to provide a basis for the reasonable evaluation of the engineering properties of mountain roadbed filler, the basic physical and strength characteristics of the Luliangshan compacted granite weathering soil were evaluated by conventional physical and mechanical tests and large triaxial tests It is found that the studied weathered soils exhibit the characteristics of particle crushing at lower confining pressures. According to the existing research results, the relationship between peak stress ratio M_f and state stress ratio M_c of granite weathered soil was corrected, and the elasto-plastic constitutive model of weathered granite in Luliangshan Mountain was determined. Based on the continuity assumption of isotropic compression-unloading test and initial shear, all the model parameters of the constitutive relation of weathered soils with modified strength are finally obtained by combining with Duncan-Chang model. By comparing the calculation results with the experimental results, it is verified that the product of the peak stress ratio and the state stress ratio is reasonable as the power function of the average principal stress.