低温冻结状态下岩石的变形特性及力学行为研究

为研究冻土地区不同含水状态下冻结岩石的力学行为,对凝灰岩和玄武岩冻土试件进行了常温20℃和低温-20℃下的单轴压缩试验和巴西劈裂试验.通过观察其变形行为和声发射活动,研究了其断裂破坏过程以及饱水率对材料强度和变形性能的影响.结果表明,冻结岩石的破裂过程分为以下几个阶段:Ⅰ阶段为裂纹气孔闭合;Ⅱ阶段为弹性变形;Ⅲ阶段为裂...

Study on deformation characteristics and mechanical behavior of rock under low temperature freezing state

In order to study mechanical behaviorof frozen rock under different water content in frozen soil area, the uniaxial compression test and Brazilian splitting test of tuff and basalt frozen soil specimens at room temperature 20 ℃ and low temperature －20 ℃ were carried out. By observing its deformation behavior and acoustic emission activity, the fracture failure process and the effect of water content on the strength and deformation properties of the material were studied. The results showed,the fracture process of frozen rock can be divided into the following stages:Ⅰ stage is crack pore closure;Ⅱ stage is elastic deformation;Ⅲ stage is crack initiation and stable crack propagation;Ⅳ stage is unstable crack propagation. At the same time, the stress level at the beginning of stage Ⅲ increases with the increase of water saturation. The peak stress intensity and strain increase with the increase of water content, and the relationship between them can be approximated by a straight line. Rock brittleness decreases with the increase of water content, and the influence of indirect tensile strength on water content is more sensitive than uniaxial compressive strength.