TBM边刀作用下花岗岩围岩裂纹特征研究  

Cracking characteristics of granite surrounding rock under TBM edge cutter fragmentation

作　　者：王春萍[1,2] 马洪素 陈亮[1,2] 赵星光 刘健[1,2] 刘建锋 李翔[1,2] WANG Chunping;MA Hongsu;CHEN Liang;ZHAO Xingguang;LIU Jian;LIU Jianfeng;LI Xiang(Beijing Research Institute of Uranium Geology,Beijing 100029,China;CAEA Innovation Center for Geological Disposal of High-Level Radioactive Waste,Beijing 100029,China;College of Water Resource and Hydropower,Sichuan University,Chengdu,Sichuan 610065,China)

机构地区：[1]核工业北京地质研究院,北京100029 [2]国家原子能机构高放废物地质处置创新中心,北京100029 [3]四川大学水利水电学院,四川成都610065

出　　处：《岩石力学与工程学报》2024年第12期2968-2979,共12页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(42307258);核设施退役治理专项资助科研项目(科工二司[2020]194号)。

摘　　要：我国首座用于高放废物地质处置技术研发的北山地下实验室,其斜坡道采用全断面隧道掘进机(TBM)“北山1号”开挖。以斜坡道洞壁钻孔岩芯为研究对象,通过CT扫描、电镜扫描和荧光显像测试等技术手段,分析TBM边刀破岩作用下花岗岩围岩的裂纹特征。试验结果表明,TBM边刀破岩形成的裂纹率很低,为0.13%~0.35%,且多为等效直径低于120μm的微裂纹。边刀破岩形成的裂纹主要分布于滚刀刀槽的正下方,且相邻刀槽底部的中间主裂纹基本不会连通,尤其是相邻刀槽下的裂纹密集区相隔较远。岩石内部裂纹大部分穿过矿物颗粒进行扩展,但在距开挖面较远的、强度较高的石英颗粒附近,裂纹会优先沿着矿物边界耗能较小的方向进行扩展。边刀破岩形成的压碎区和裂纹密集区呈非对称锥形分布,中间主裂纹的倾斜角度与边刀的安装角度相关。3种方法测得由边刀破岩造成的裂纹扩展深度均不超过1.60 cm,其中电镜扫描测试的精度最高,CT扫描与荧光显像法的测试精度接近,但荧光显像测试中裂纹与完整岩石的对比度更高,更有利于裂纹的提取和测量。Beishan underground research laboratory(URL)is the first URL in China for the research and development of geological disposal technology of high-level radioactive waste.The ramp in Beishan URL is excavated by full section tunnel boring machine(TBM),namely“Beishan-1”.This paper takes the cores drilled from the ramp as the research object,and studies the cracking characteristics of granite surrounding rock under TBM edge cutter fragmentation,by CT scanning,electron microscope scanning and fluorescence imaging tests.The experimental results indicate that,the cracking rate induced by TBM edge cutter is very low,about 0.13%-0.35%,and most of them are microcracks with equivalent diameter less than 120μm.The cracks induced by TBM edge cutter fragmentation are mainly distributed directly below the groove of the cutter.The central main cracks at the bottom of the adjacent grooves are almost not connected,especially the crack concentration areas under the neighboring grooves are far apart.Most of the cracks in the rock propagate through the mineral particles.However,in the vicinity of quartz particles with higher strength that are far away from the excavation surface,the fractures preferentially propagate along the direction with less energy consumption at the mineral boundary.The crushing zone and crack intensive zone induced by edge cutter are asymmetrically conical distribution,and the inclination angle of the central main crack is related to the installation angle of edge cutter.The crack propagation depth caused by edge cutter is less than 1.60 cm measured by the three methods,among which the electron microscope scanning test has the highest accuracy.The test accuracy of CT scanning and fluorescence imaging is close,but the contrast between fracture and intact rock in fluorescence imaging test is higher,which is more conducive to fracture extraction and measurement.

关 键 词：岩石力学 北山地下实验室 TBM滚刀破岩裂纹 CT扫描 电镜扫描 荧光显像测试 

分 类 号：TU45[建筑科学—岩土工程]