真三轴多面快速卸荷岩爆多余能量特征实验研究
Excess energy characteristics of true triaxial multi-faceted rapid unloading rockburst
李杰宇 1刘冬桥 2何满潮 2杨劲松1
作者信息
- 1. State Key Laboratory for Tunnel Engineering,China University of Mining and Technology(Beijing),Beijing 100083,China;School of Mechanics and Civil Engineering,China University of Mining and Technology(Beijing),Beijing 100083,China
- 2. State Key Laboratory for Tunnel Engineering,China University of Mining and Technology(Beijing),Beijing 100083,China
- 折叠
摘要
利用自主研发的真三轴岩爆实验系统,进行了一系列真三轴高压加载下水平方向不同快速卸荷面数的滞后性岩爆实验.基于能量理论,实验研究了不同卸荷面数下的岩爆储能特征、多余能量(ΔE)、多余能量释放速度(EERR)以及AE裂纹演化特征.实验得出了以下主要结论:1)岩爆的发生相较于岩石单轴加载静态破坏,主要是由于多余能量ΔE的产生,多余能量ΔE取决于岩石在岩爆前所存储的弹性应变能、峰后设备输入的能量以及残余弹性应变能,随着卸荷面数的增加,ΔE逐渐减小,但多余能量释放速度EERR却增大,导致岩爆现象变得更为剧烈;2)在真三轴高压加载条件下进行快速卸荷,会使应力应变曲线出现卸荷平台,卸荷损伤主要以张拉破坏为主,并主要集中在临空面附近,随着卸荷面数的增加卸荷损伤逐渐增大;3)在砂岩的损伤演化过程中,拉伸裂纹占据主导地位,而在最终临近岩爆阶段,剪切裂纹曲线的斜率大于拉伸裂纹,表明剪切裂纹是导致试样失稳破坏的关键因素.
Abstract
Delayed rockburst experiments with different numbers of unloading surfaces(DNUS)were performed using an independently developed true triaxial multisurface unloading rockburst experimental system.Based on the rockburst excess energy theory,the energy storage characteristics,excess energy,excess energy release rate(EERR),and crack evolution characteristics of rockbursts with DNUS were studied,and the following main conclusions were obtained.The occurrence of rockbursts is mainly due to the generation of an excess energy ΔE.ΔE depends on the elastic strain energy stored in the rock before the rockburst,the energy input by the equipment after the peak,and the residual elastic strain energy.As the DNUS increases,ΔE gradually decreases,but the EERR value increases,and the rockburst becomes increasingly severe;Rapid unloading of the specimen under true triaxial high-pressure loading will produce an unloading platform in the stress-strain curve,causing unloading damage.The damage is mainly concentrated near the free surface in the form of tension failure,and the unloading damage gradually increases with increasing DNUS;Tensile cracks play a dominant role in the damage and destruction of sandstone.In the final rockburst stage,the slope of the shear crack curve was greater than that of the tensile cracks,indicating that shear cracks were a critical factor affecting the instability and failure of the specimen.
关键词
真三轴岩爆实验/多余能量/多余能量释放速度/快速卸荷/裂纹演化Key words
True triaxial rockburst experiment/excess energy/excess energy release rate/rapid unloading/crack evolution引用本文复制引用
基金项目
国家自然科学基金(52074299)
国家自然科学基金(41941018)
中央高校基本科研业务费专项(2023JCCXSB02)
出版年
2024
NETL
NSTL
万方数据