摘要
实时准确掌握岩石破坏全过程中内部裂隙扩展演化规律,对于科学指导地下岩体工程稳定性控制,推动矿山资源安全开采具有重要的工程意义。研制一套能够与CT扫描系统配套的真三轴加载试验设备,位于CT扫描区域的设备部件均采用新型碳纤维材料的设计,包含竖向加载系统、横向加载系统、真三轴压力室等核心部件,使得X射线能够有效通过装置中预先设计的CT扫描区域,实现了真三轴应力环境下实时CT扫描的功能。利用该设备开展了三轴不同应力条件下完整岩石和含裂隙岩石加载实时CT扫描试验,获得了整个加载过程中岩石应力-应变曲线。获取了不同工况下岩石内部裂纹形态的空间三维CT特征,结果发现:与CTT条件下岩石内部裂纹复杂的空间扩展形态相比,TTT条件下岩石内部裂纹空间形态简单,为一沿σ_(2)方向的平面裂纹。说明了真三轴条件下岩石内部裂隙具有明确的扩展方向(沿σ_(2)方向扩展)。TTT-c2(含裂隙且沿σ_(2)方向)和TTT-c3(裂隙沿σ_(3)方向) 2种工况下岩石内部均出现了4条萌生裂纹,但前者萌生裂纹均与预制裂纹前缘线共面,而且预制裂纹面仍然基本保持完整;后者均与预制裂纹前缘线垂直,呈现横切预制裂隙的趋势,最终形成了复杂的裂隙网络,导致预制裂隙多处出现挤压破坏。真三轴3种工况下所有的裂纹倾角分布极为集中,均与σ_(2)方向大致平行,表明了中间主应力对岩石内部萌生裂纹扩展方向起到决定性的作用,岩石内部裂隙扩展发育过程强烈依赖中间主应力方向。
The real-time and accurate grasp of the internal fracture expansion and evolution law in the whole process of rock failure is of great engineering significance for scientifically guiding the stability control of underground rock engineering and promoting the safe mining of mineral resources.A set of true triaxial loading test equipment that can be matched with the CT scanning system has been developed.The equipment components located in the CT scanning area are designed with new carbon fiber materials,including core components such as vertical loading system,lateral loading system,true triaxial pressure chamber,etc.,so that X-rays can effectively pass through the pre-designed CT scanning area in the device.The function of real-time CT scanning under true triaxial stress environment is realized.This equipment is used to carry out real-time CT scanning tests of intact rock and rock with fractures under triaxial different stress conditions,and obtained the rock stress-strain curve during the entire loading process.The spatial three-dimensional CT characteristics of the internal cracks in the rock under different working conditions are obtain,and the results show that:compared with the complicated spatial expansion of the internal cracks in the rock under the CTT condition,the spatial morphology of the internal cracks in the rock under the TTT condition is simple,which is a plane crack alongσ_(2) directions.It shows that under true triaxial conditions,the internal fractures of the rock have a clear expansion direction(expanding along theσ_(2) direction).Four initiation cracks appeared in the rock under the two conditions of TTT-c2(with cracks along theσ_(2) direction)and TTT-c3(cracks along theσ_(3) direction).However,the initiation cracks of the former are all coplanar initiation cracks with the front edge of the pre-crack,and the pre-crack surface remains basically intact.The latter are all perpendicular to the front of the pre-crack,showing a trend of transversely cutting the pre-crack.Eventually a complex network of fractures is formed,resulting in more prefabricated fractures and backlog damage.Under the three working conditions of true triaxial,all the crack inclination angle distributions are extremely concentrated,which are roughly parallel to theσ_(2) direction.It shows that the intermediate principal stress plays a decisive role in the propagation direction of initiating cracks in the rock,and the propagation and development process of the internal rock cracks strongly depends on the direction of the intermediate principal stress.
作者
李兆霖
王连国
姜崇扬
陆银龙
李文帅
LI Zhaolin;WANG Lianguo;JIANG Chongyang;LU Yinlong;LI Wenshuai(School of Mines,China University of Mining&Technology,Xuzhou 221116,China;High-Tech Research Center for Open Pit Mines,China University of Mining and Technology,Xuzhou 221116,China;State Key Laboratory for Geomechanics and Deep Underground Engineering,China University of Mining&Technology,Xuzhou 221116,China;School of Civil Engineering and Architecture,Shandong University of Science and Technology,Qingdao 266590,China)
出处
《煤炭学报》
EI
CAS
CSCD
北大核心
2021年第3期937-949,共13页
Journal of China Coal Society
基金
中央高校基本科研业务费专项资金资助项目(2020QN42)。
关键词
岩石
真三轴
实时CT
裂隙扩展
空间三维重构
rocks
true triaxial
real-time CT
fracture extension
three-dimensional reconstruction
作者简介
李兆霖(1990—),男,河南巩义人,博士后。E-mail:lzhlcumt@163.com;通讯作者:王连国(1964—),男,山东高唐人,教授。E-mail:cumt_lgwang@163.com。
