凝灰质粉砂岩力学特性和本构方程的研究

发布时间：2018-04-26 04:14

本文选题：凝灰质粉砂岩 + 含水量　；参考：《西华大学》2017年硕士论文

【摘要】：自然界中水和岩石是同时存在的,且二者之间进行着繁杂的物理和化学作用,影响岩石的力学特性特性。自然界中水对岩石的浸蚀破坏是从岩石结构表面开始的,因此同类岩石的力学性质在不同含水状态环境下的力学性质差异很大。在隧道的开挖和支护中精确把握住岩石的力学性质是工程安全、质量和进度的保证。所以探究不同含水状态下岩石的力学特性就显得十分重要,是地下空间与隧道界研究的一个重中之重的课题。本文将浙江省丽水市路湾隧道的凝灰质粉砂岩作为研究对象,利用理论与试验相结合的思路,探究了不同含水状态下的凝灰质粉砂岩的力学特性。主要内容如下:(1)取少量岩样的粉晶样品送成都理工大学材料与化学化工学院综合实验中心,通过DX-2700 X射线衍射仪分析凝灰质粉砂岩物质成分和含量。(2)通过凝灰质粉砂岩在自然状态下的吸水性试验。了解凝灰质粉砂岩自然吸水率和时间之间的曲线关系,据此设定了直剪、单轴压缩和三轴压缩试验中岩样的泡水时间点。(3)使用成都理工大学自主研发的携带式岩石力学多功能试验仪进行不同浸水时间下标准试样的直剪试验。以试验结果为依据,分析浸水时间与含水率之间的曲线关系,从而获得剪切力及力学参数与浸水时间之间的关系,构建以浸水时间t为因量的MohrCoulomb准则。(4)使用MTS岩石综合测试系统对凝灰质粉砂岩进行常温下不同浸水状态下的单轴压缩试验。得到不同浸水状态下的岩样σ-ε曲线关系、单轴抗压强度和力学参数,研究浸水时间与含水率之间的关系,进而探究浸水时间对岩石强度、变形及各力学参数的影响,并建立以浸水时间为变量的岩石本构关系。(5)使用MTS815.03型岩石三轴伺服刚性试验机进行自然状态下3σ=5、10、25、40、60MPa的三轴压缩试验。得到不同围压的岩样σ-ε曲线、岩石强度和力学参数。进而研究围压对岩石强度、破坏特征及各力学参数的影响并建立常规三轴本构方程。(6)使用MTS815.03型岩石三轴伺服刚性试验机进行3σ=60MPa高围压不同浸水状态下的三轴压缩试验。得到浸水时间t=0、4、12、360h下的岩样的三轴σ-ε曲线、三轴抗压强度和力学参数。进而研究浸水时间和含水率在高围压下对岩石强度、变形及各力学参数的影响并建立以浸水时间为变量的岩石三轴损伤本构关系。
[Abstract]:In nature, water and rock exist at the same time, and there are a lot of physical and chemical interactions between them, which affect the mechanical properties of rock. The erosion failure of rock by water in nature starts from the surface of rock structure, so the mechanical properties of the same rock in different water-bearing conditions are very different. It is the guarantee of engineering safety, quality and schedule to accurately grasp the mechanical properties of rock in the excavation and support of tunnel. Therefore, it is very important to explore the mechanical properties of rock in different water-bearing states, which is the most important subject in the study of underground space and tunnel boundary. In this paper, the tuffaceous siltstone in Luwan Tunnel of Lishui City, Zhejiang Province, is taken as the research object, and the mechanical properties of tuffaceous siltstone under different water-bearing conditions are explored by combining theory with experiment. The main contents are as follows: (1) take a small amount of rock samples of powdery crystals and send them to the Comprehensive Experimental Center of the School of Materials and Chemical Engineering, Chengdu University of Technology, The material composition and content of tuffaceous siltstone were analyzed by DX-2700 X-ray diffractometer. The relationship between the natural water absorption rate and the time of tuffaceous siltstone is understood. In uniaxial compression test and triaxial compression test, the time point of water bubble of rock samples was measured by means of the portable multifunctional rock mechanics tester developed by Chengdu University of Technology. The direct shear tests of standard samples were carried out under different soaking times by using the portable multifunction test instrument developed by Chengdu University of Science and Technology (Chengdu University of Science and Technology). Based on the experimental results, the relationship between soaking time and water content is analyzed, and the relationship between shear force, mechanical parameters and soaking time is obtained. In this paper, the MohrCoulomb criterion, which is based on the factor t of soaking time, is constructed. (4) the uniaxial compression tests of tuffaceous siltstones under different soaking conditions are carried out under normal temperature by using MTS rock comprehensive test system. The relations of 蟽-蔚 curves, uniaxial compressive strength and mechanical parameters of rock samples under different soaking conditions are obtained. The relationship between soaking time and water content is studied, and the influence of soaking time on rock strength, deformation and mechanical parameters is explored. The constitutive relation of rock with immersion time as variable was established. The MTS815.03 triaxial servo rigid testing machine was used to carry out the triaxial compression tests under natural condition. The 蟽-蔚 curves, rock strength and mechanical parameters of rock samples with different confining pressures are obtained. Furthermore, the influence of confining pressure on rock strength, failure characteristics and mechanical parameters was studied, and a conventional triaxial constitutive equation was established. The triaxial compression tests were carried out under 3 蟽 60 MPA high confining pressure under different immersion conditions using MTS815.03 type rock triaxial servo rigid test machine. The triaxial 蟽-蔚 curves, triaxial compressive strength and mechanical parameters of the rock samples were obtained at the immersion time t 0 ~ (0) ~ (4) ~ (3) ~ (3) ~ (3) ~ (3) ~ (36) h. The influences of immersion time and water content on the strength, deformation and mechanical parameters of rock under high confining pressure were studied and the constitutive relation of rock triaxial damage was established.
【学位授予单位】：西华大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU452

【参考文献】