论文部分内容阅读
基于碎屑岩组织结构疏松、含水率较高、物理力学性能较差、呈孔隙式胶结接触等特点,对碎屑砂岩首先开展了物理特性试验分析,认为其微、细观结构复杂、内部破坏严重,矿物成分为石英、长石、绢云母等,化学成分以SiO2为主,属微透水、小孔隙率砂岩,且渗水化学侵蚀并不显著。其次,开展了静水压力、单轴压缩和三轴压缩试验,研究了碎屑砂岩的强度和变形破坏特性。最后,初步探索了物理特性与强度变形特性的关系。结果表明,静水压力为2.6 MPa时,岩样内部微缺陷压密完成;单轴压缩曲线呈明显6阶段特征,峰值应力达0.98 MPa,属脆-延性破坏;三轴压缩条件下,岩样呈压缩为主的延性扩容破坏,轴向压缩和环向体积扩容达6%和4%;曲线无明显破坏荷载,呈现非线性、塑性硬化、存在屈服平台和体积由压缩向扩容过渡等特性。且体积扩容破损应力与屈服应力基本相同,扩容转折点随围压增加而增大,围压可增强岩样抵抗变形破坏的能力。试验结果旨在为岩石工程稳定分析及本构模型构建提供可靠的依据。
Based on the characteristics of loose structure, high water content, poor physical and mechanical properties and pore-cement contact, clastic rocks are firstly tested for physical characteristics of clastic sandstone. The results show that the micro-meso-structure is complex and the internal damage Serious, the mineral composition of quartz, feldspar, sericite, chemical composition of SiO2-based, is a micro-permeability, small porosity sandstone, and water seepage chemical attack is not significant. Secondly, hydrostatic pressure, uniaxial compression and triaxial compression tests were carried out to study the strength and deformation and failure characteristics of clastic sandstone. Finally, the relationship between the physical properties and the strength and deformation characteristics is tentatively explored. The results show that when the hydrostatic pressure is 2.6 MPa, the microdefects within the rock sample are compactly compacted. The uniaxial compression curve shows a six-stage characteristic with a peak stress of 0.98 MPa, which is a brittle-ductile failure. Under triaxial compression conditions, Compression-based ductile expansion failure, axial compression and hoop volume expansion of 6% and 4%; curve without obvious damage to the load, showing nonlinear, plastic hardening, there is yield platform and the volume from compression to expansion transition characteristics. And the volumetric expansion failure stress and yield stress are basically the same, expansion turning point increases with the confining pressure increases, the confining pressure can enhance the ability of rock samples to resist deformation and failure. The test results are intended to provide a reliable basis for the stability analysis of rock engineering and the construction of constitutive model.