关键词: 加载速率, 劈裂, 微观形貌, 高度特征参数, 纹理特征参数, 能量

Abstract: In order to study how the tensile strength of sandstone influenced by loading rate, a series of splitting tests are carried out with five loading rates. Based on the comprehensive analysis of the splitting tensile strength, destructive features, the change rule and correlation between microstructure of the splitting surface and energy parameters, the results show that: (1) The split tensile strength of sandstone gradually decrease as loading rate increase, and generally go slow after the first steep upward trend. When loading rate is between 0.01 kN/s to 0.10 kN/s, the tensile strength grew significantly and then tended to slow down at 0.1 kN/s to 1.00 kN/s. (2) Total energy the sample absorbed increase as loading rate increase, and the ratio of elastic strain energy to total energy increases while dissipated energy go down, the time when the crack propagation formed into splitting surface is an order of magnitude less, which indicates the sudden destruction of rock sample enhanced resulted by release of elastic strain energy when peak stress reached, which result in tensile strength enhanced and increasingly complicated micro morphology characteristics. (3) During the rock splitting test, loading rate, energy parameter, features of splitting surface and tensile strength are closely related; first of all, the loading rate affects the total amount and distribution of energy ,and the changes in energy parameters affects its destruction process and features of splitting surface; finally, the difference in tensile strength shows. The related analysis methods and ideas references can provide a better reference for similar tests.

Key words: loading rate, splitting, microstructure, height feature parameters, texture feature parameters, energy