单轴压缩下脆性岩石损伤破坏能量演化规律试验研究  

EXPERIMENTAL STUDY ON DAMAGE AND FAILURE ENERGY EVOLUTION OF BRITTLE ROCKS UNDER UNIAXIAL COMPRESSION

作　　者：刘冬桥[1] 郭允朋 李杰宇 凌凯 葛嘉诚 LIU Dongqiao;GUO Yunpeng;LI Jieyu;LING Kai;GE Jiacheng(State Key Laboratory for Geomechanics and Deep Underground 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)

机构地区：[1]中国矿业大学(北京)深部岩土力学与地下工程国家重点实验室,北京100083 [2]中国矿业大学(北京)力学与建筑工程学院,北京100083

出　　处：《工程地质学报》2023年第3期843-853,共11页Journal of Engineering Geology

基　　金：国家自然科学基金(资助号:52074299,41941018)。

摘　　要：脆性对岩石破裂模式及损伤演化过程具有重要影响。本文对采自某铁路隧道群的6种不同岩性的脆性岩石开展单轴压缩试验,在分析其应力-应变过程、破坏模式和能量演化特征的基础上,综合考量峰前弹性能积聚率、峰后能量耗散程度及耗散速率,建立一种基于岩石应力-应变曲线全过程的脆性指数计算方法,进一步基于能量耗散表征损伤变量,分析了脆性岩石损伤演化过程,并探讨了从损伤演化角度建立脆性评价指标的可行性和合理性。结果表明:(1)试验所采用的6种不同岩性岩石应力-应变曲线峰后段均表现出不同程度的脆性跌落现象。(2)基于本文建立的脆性指标对6种岩石进行脆性定量评价和比较,脆性程度由大到小依次为:辉长岩、变质砂岩、石英片岩、粗粒花岗岩、板岩、大理岩。(3)单轴压缩条件下,基于能量耗散表征的脆性岩石损伤演化过程整体呈“S”型发展趋势,可分为初始损伤、损伤保持、损伤稳定发展、损伤加速发展以及损伤减缓至终止5个阶段,能够很好地反映岩石内部微裂纹压密闭合、萌生发育、扩展贯通直至宏观破坏的整个过程。This research is supported by the National Natural Science Foundation of China(Grant Nos.52074299,41941018)Brittleness plays an important role in rock fracture mode and damage evolution.In this paper,uniaxial compression tests were carried out on 6 kinds of brittle rocks with different lithology from a railway tunnels.Based on the analysis of stress-strain process,failure mode and energy evolution characteristics,a calculation method of brittleness index was established by comprehensively considering the pre-peak elastic energy accumulation rate,post-peak energy dissipation degree and dissipation rate.Furthermore,the damage variable was characterized by energy dissipation,and the feasibility and rationality of establishing brittleness evaluation index from the perspective of damage evolution were discussed.The results show that:(1)The stress-strain curves of different rocks show different degrees of brittle drop after the peak.(2)Based on the brittleness index established in this paper,the brittleness degree is in the order of gabbro,metasandstone,quartz schist,coarse-grained granite,slate and marble.(3)The damage evolution process of brittle rock based on energy dissipation presents an“S”shaped development trend,which can be divided into five stages:initial damage,damage maintenance,damage stable development,damage accelerated development and damage mitigation to termination,which can well reflect the whole process of micro-crack pressure sealing,initiation and development,expansion and penetration until macroscopic failure in rock.

关 键 词：单轴压缩 脆性指数 能量 损伤演化 

分 类 号：TD324[矿业工程—矿井建设]