摘要
本文针对云南红土高原地区存在的特殊岩土混合体—类岩堆体,通过室内直剪试验研究了其抗剪强度,发现含石率为100%的类岩堆体呈现应变硬化的剪切特性。基于随机生成不规则块石理论,采用PFC数值模拟直剪试验过程,在保证级配、细观参数相同的情况下,研究不同孔隙率的类岩堆体抗剪强度,结果表明:开始剪切阶段,孔隙率越小,剪应力越大,不同孔隙率的试样剪应力差值较大,随着块石压密、剪碎、剪应力差值缩小,研究成果对红土高原地区隧道施工参数选取具有指导意义。
In this study, the shear strength of the special soil-rock mixture-talus-like rock mass in the Late-rite Plateau area of Yunnan was studied through direct shear test, and it was found that the talus- like rock mass with volume block porosity of 100% showed strain-hardened shear characteristics. Based on the theory of random generation of irregular blocks, the PFC simulation of the straight shear test process, under the condition of ensuring the same gradation and mesoscopic parameters, the shear strength of talus-like rock mass with different porosity is studied, and the results show that the smaller the porosity at the beginning of the shear stage, the greater the shear stress, the larger the shear stress difference of the specimens of different porosity, and the shear stress difference of the specimen is reduced with the compaction and shearing of the block. This study has guiding significance for the selection of tunnel construction parameters in the laterite plateau area.
