砂质泥岩峰后破裂承载特征与块体分布规律研究  

Post-peak fracture-bearing characteristics and fragmentation distribution of sandy mudstone

作　　者：辛子朋 柴肇云[1] 孙浩程 李天宇 刘新雨 段碧英 XIN Zi-peng;CHAI Zhao-yun;SUN Hao-cheng;LI Tian-yu;LIU Xin-yu;DUAN Bi-ying(Key Laboratory of In-situ Property-Improving Mining of Ministry of Education,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China)

机构地区：[1]太原理工大学原位改性采矿教育部重点实验室,山西太原030024

出　　处：《岩土力学》2023年第8期2369-2380,共12页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.52274091,No.51974193)。

摘　　要：岩石峰后阶段的变形承载规律对巷道破碎区围岩的稳定性控制具有重要意义。为研究岩石峰后阶段的破裂演化规律与承载特征,以砂质泥岩为试验对象,开展了控制应变量为峰值应变不同倍数的单轴压缩试验,并应用非线性分形理论阐明了峰后破裂块体的分布规律。基于试验结果,构建了峰后含贯通破裂面岩样的力学分析模型。结果表明:(1)砂质泥岩全应力-应变曲线呈现出单峰状与多峰状两种形态的峰后应力跌落方式;(2)峰后阶段,试样破坏模式由低倍峰值应变下的张性破坏逐渐转变为高倍峰值应变下的剪切滑移破坏;(3)同应变量下试样破裂块体的分形维数内部大于外部,且二者与试样的峰后应变倍数值均具有显著的正相关性;(4)岩石在峰后阶段的持续破坏方式与块体间接触破裂面特性有关,破裂块体仅会在一定的倾角范围内沿破裂面滑动,依据所建立的分析模型可准确解释砂质泥岩峰后阶段破裂承载特性与块体分布规律。The deformation-bearing law of rock at the post-peak stage is of great significance to the stability control of the surrounding rock in the fragmented zone of the roadway.To study the rupture evolution and bearing characteristics at the post-peak stage of the rock,the uniaxial compression tests with different multiples of the peak strain value as the control strain were carried out on sandy mudstone,and the nonlinear fractal theory was applied to elucidate the distribution pattern of the post-peak ruptured masses.Based on the test results,a mechanical analytical model for rock samples containing penetrating fracture surfaces in the post-peak phase was established.The results show that:(1)The complete stress-strain curve of sandy mudstone presents two forms of post-peak stress drop,i.e."single peak"and"multi-peak".(2)The post-peak specimen damage mode gradually changes from tensile damage under low-multiples peak strain to shear slip damage under high-multiples peak strain.(3)The fractal dimension of the internal fragments of the specimen is greater than that of the surface fragments for the same strain,and both of them have a significant positive correlation with the multiple of the post-peak strain of the specimen.(4)The continuous failure mode of rock at the post-peak stage is related to the characteristics of the contact fracture surface between fragments,and the fragments will only slide along the fracture surface within a certain dip angle range.The established analytical model can accurately explain the fracture-bearing characteristics and fragmentation distribution of the sandy mudstone at the post-peak stage.

关 键 词：岩石力学 破碎区 峰后承载 破裂块体 分形维数 

分 类 号：TU452[建筑科学—岩土工程]