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研究选取四川得荣县的玄武质凝灰岩为研究对象,按照固定围压200 MPa,实验温度为200℃～800℃开展高温高压实验,取得7个样品的实验数据。通过对实验数据的分析可知,在围压一定,实验温度不断升高的条件下,岩样的弹性模量和屈服强度都不断降低,当实验温度达到700℃,岩样变形主要以流变为主。实验温度400℃是岩样力学性质发生显著变化的临界温度。通过对实验后样品的成份分析可知,当实验温度超过400℃后,岩样中的黏土矿物含量随着温度的升高而降低,而斜长石和方解石的含量在不断升高,当温度超过500℃以后,岩样中出现了新的矿物——橄榄石;岩样的电镜扫描结果显示,在400℃之前,岩样内基本没有明显的微裂隙,但是当温度达到700℃和800℃时,岩样内出现明显的部分熔融现象,温度越高,部分熔融现象越明显,而且在800℃时,出现明显的矿物重结晶现象。微观的结构及成份的变化导致了宏观的物理力学性能的显著变化。本次实验研究结论与前人研究成果较为一致,但是从物质成份和样品微结构方面对岩石力学性能对高温响应的机理进行了初步解释。
The study selected basaltic tuff from DeRongXian County, Sichuan Province as the research object, and carried out high temperature and pressure experiments according to the fixed confining pressure of 200 MPa and experimental temperature of 200 ℃ to 800 ℃. Experimental data of seven samples were obtained. Through the analysis of the experimental data, we can see that the elastic modulus and yield strength of the rock samples decrease continuously with the confining pressure constant and the experimental temperature rising. When the experimental temperature reaches 700 ℃, the Lord. The experimental temperature of 400 ℃ is a critical temperature for the significant change of the rock mechanics properties. Through the analysis of the composition of the samples after the experiment, the clay mineral content in the rock samples decreases with the increase of temperature when the experimental temperature exceeds 400 ℃, while the content of plagioclase and calcite increases continuously. When the temperature exceeds 500 ℃, ℃, the new mineral-olivine appeared in the rock sample. The scanning electron microscopy of the rock sample showed that there were no obvious micro-cracks in the rock sample before 400 ℃, but when the temperature reached 700 ℃ and 800 ℃, Part of the melting phenomenon is obvious in the rock samples. The higher the temperature, the more obvious the partial melting phenomenon, and the obvious mineral recrystallization appears at 800 ℃. Microscopic structure and composition changes lead to significant changes in the physical and mechanical properties of the macro. The conclusion of this experiment is consistent with the previous research results. However, the mechanism of rock mechanics response to high temperature is primarily explained from the aspects of material composition and microstructure.