基于损伤的黏聚力弱化-摩擦角强化模型对大型地下洞室群围岩稳定性的影响  

Effects of a Damage-based CWFS Model on Rock Mass Stability in Large Underground Caverns

作　　者：钱苗苗 冷先伦[2,3] 王川 李海轮 李刚 QIAN Miao-miao;LENG Xian-lun;WANG Chuan;LI Hai-lun;LI Gang(School of Civil Engineering and Architecture,Anhui University of Science and Technology,Huainan 232001,China;State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Science,Wuhan 430071,China;School of Engineering Science,University of Chinese Academy of Sciences,Beijing 100049,China;PowerChina Beijing Engineering Corporation Limited,Beijing 100024,China)

机构地区：[1]安徽理工大学土木建筑学院,淮南232001 [2]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,武汉430071 [3]中国科学院大学工程科学学院,北京100049 [4]中国电建集团北京勘测设计研究院有限公司,北京100024

出　　处：《科学技术与工程》2021年第9期3763-3769,共7页Science Technology and Engineering

基　　金：国家重点研发计划(2017YFF0108706,2017YFF0108705)。

摘　　要：岩体的峰后强度对大型地下洞室群围岩开挖变形稳定具有较大影响。针对此问题,采用基于损伤的黏聚力弱化-摩擦角强化(cohesion weakening and friction strengthening, CWFS)模型并以动态链接库(dynamic link library, DLL)的形式植入FLAC~(3D)程序中,针对依托工程的大型地下洞室群围岩开挖稳定性,开展考虑围岩开挖损伤和不考虑损伤的开挖全过程模拟。通过分析围岩的变形、应力、塑性区与损伤区的规律及其与现场监测数据的对比,研究开挖损伤对围岩稳定性的影响。结果表明:考虑围岩开挖损伤相对于不考虑损伤时,围岩应力释放程度较高,不利于地下洞室群的稳定;围岩塑性区和变形在主厂房顶拱与边墙等区域增加至1.5~2.0倍。CWFS模型能有效反映围岩塑性屈服的诱因,即损伤系数在0.5~1.0范围内为开挖卸荷导致的屈服,损伤系数在0~0.5范围内为开挖损伤导致的屈服;采用该模型得到的围岩开挖变形在量值上与采用多点位移计得到的现场监测值相近,变化趋势基本相同,不考虑围岩开挖损伤时得到分析结果相对于实际工程偏危险。The post-peak strengths of rock masses have a great influence on the stabilities and deformations of large underground caverns.To analyze the stability of the large underground caverns in a power station,a damage-based model,i.e.,the cohesion weakening and friction strengthening(CWFS)model was implanted into the FLAC 3D program as a dynamic link library(DLL)file,and used to simulate the excavation course of underground caverns,considering and ignoring the excavation damages of the rock masses,separately.By analyzing the deformation,stress,plastic zones,and damage zones of the surrounding rock masses and comparing them with the on-site monitoring results,the effects of the excavation damages on the stability were studied.Results show that compared with those calculated by ignoring the excavation damage,the stresses calculated by considering the damage are released highly,which is not conducive to the stability.The plastic zones and deformations in the crown and high walls of the powerhouse cavern are increased by 1.5 to 2.0 times.The CWFS model can effectively reveal the inducements of the plastic zones,and those with damage factors ranging from 0.5 to 1.0 are caused by the excavation unloading while those ranging from 0 to 0.5 are caused by the excavation disturbance.The deformation magnitudes and trends calculated by the model are similar to the on-situ data monitored by multi-point displacement meters,while those calculated by ignoring the damage are underestimated,which can be risky.

关 键 词：地下洞室群 CWFS损伤模型 围岩损伤 变形规律 围岩稳定 

分 类 号：TU457[建筑科学—岩土工程]