Influence of unloading paths on sandstone damage characteristics and energy evolution law under stress-seepage coupling

被引:0
|
作者
Zhang Pei-sen [1 ,2 ]
Xu Da-qiang [1 ,2 ]
Yan Wei [1 ,2 ]
Zhang Xiao-le [1 ,2 ]
Dong Yu-hang [1 ,2 ]
Zhao Ming [1 ,2 ]
机构
[1] Shandong Univ Sci & Technol, Natl Key Lab Mine Disaster Prevent & Control, Qingdao 266590, Shandong, Peoples R China
[2] Shandong Univ Sci & Technol, Natl Demonstrat Ctr Expt Min Engn Educ, Qingdao 266590, Shandong, Peoples R China
基金
中国国家自然科学基金;
关键词
rock mechanics; stress-seepage coupling; unloading path; damage characteristics; energy evolution; DEFORMATION CHARACTERISTICS; MECHANICAL-PROPERTIES; ROCK; FAILURE; TESTS; PRESSURE; MARBLE;
D O I
10.16285/j.rsm.2023.0204
中图分类号
P5 [地质学];
学科分类号
0709 ; 081803 ;
摘要
Rock mass disasters are caused by instability driven by energy within the rock mass. The excavation and unloading disturbance can lead to fractures and instability in the rock mass structure, which is a major cause of dynamic disasters such as water inrush in stopes. To understand the influence of excavation unloading on rock mass structure fractures and to clarify the degradation law of surrounding rock and the mechanism of dynamic disasters like water inrush, this study focuses on the characteristics of rock damage and the evolution of energy under stress-seepage coupling factors. Using the Rock Top multi-field coupling tester, the study investigates the rock damage characteristics and energy evolution under three stress paths: conventional triaxial compression (group C), conventional unloading confining pressure with different initial damage degrees (group W), and cyclic loading and unloading confining pressure (group X) under the influence of stress-seepage coupling. Based on the evolution characteristics of rock elastic strain energy, the stress-strain curve of rock under conventional triaxial compression (group C) is divided into five stages, and the characteristics of U-1, U-3, U-e, U-d and permeability change in each stage are explained in detail (Ue is the elastic strain energy, U-d is the dissipated energy, U-1 is the strain energy of the rock transformed by the positive work done by the axial stress on the rock, and U-3 is the strain energy released by the negative work). During the conventional confining pressure unloading process, the evolution law of U-1 and U-3 is similar to that of group C rock, but the negative growth of U-3 is more significant. The rock input energy gradually shifts from Ue to Ud, and the initial damage degree has no significant influence on the law. During the confining pressure unloading process, the permeability shows a fluctuating upward trend, and the confining pressure is negatively correlated with the permeability. In the process of cyclic loading and unloading confining pressure, the energy evolution law is similar to that of group W rock, with energy accumulation differing only due to time effects. On the whole, regardless of the stress path, the pre-peak rock is dominated by Ue, representing energy storage, while post-peak rock is dominated by energy release and dissipation. Axial stress loading is the main influencing factor for rapid accumulation of Ue, while the change in confining pressure is not enough to cause a large change in Ue. Axial load is the primary factor influencing engineering disasters. Furthermore, there is a significant negative correlation between rock damage variable and confining pressure. The larger the confining pressure is, the smaller the Ue release ratio of rock is, and the smaller the rock damage is. Confining pressure restraint effectively enhances the energy storage capacity of rock and inhibits the dissipation and release of rock energy.
引用
收藏
页码:325 / 339
页数:15
相关论文
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