关键词: 岩石力学, 力学特性, 三轴试验, 热应力, 渗透率, 拟合模型

Abstract: Research on the heat-force-liquid coupling of rock is extremely important for deep mining engineering, nuclear waste storage, geothermal resources exploitation and utilization and other engineering fields. In an attempt to study the permeability evolution regularity of rock after high temperature, the mechanical properties of rock mass undergone thermal fracture treatment at different temperatures were analyzed in terms of strength and permeability through triaxial loading test. Rock samples collected from a mining well in Tarim were taken as research objects. Results manifested that:(1)In the initial stage of loading, the climbing of confining pressure led to lower permeability;in the mid-stage, permeability increased slowly; in the later stage of loading, permeability increased dramatically. (2) The permeability of rock increased in positive exponential relation with the rising of temperature. (3) The thermal expansion of rock was unapparent below a certain temperature, while thermal expansion induced by higher temperature would significantly damage rock structure, mitigating the increasing of elastic modulus and strength with the rise of temperature. (4) In line with the theory of thermodynamics, the rock fracture caused by thermal stress under varying temperature was deduced, and the model of permeability varying with temperature was obtained. The results offer reference for the study of multi-field coupling under high temperature.

Key words: rock mechanics, mechanical properties, triaxial test, thermal stress, permeability, fitting model