大跨度扁平隧洞围岩松动圈数值模拟研究  

Numerical Simulation Study on Loosened Zone of Surrounding Rock of Large-span Flat Caverns

作　　者：雷中岱 孔新立 王文烨 闫治国[1,2] LEI Zhongdai;KONG Xinli;WANG Wenye;YAN Zhiguo(State Key Laboratory for Disaster Reduction in Civil Engineering,Tongji University,Shanghai 200092;Department of Geotechnical of Geotechnical Engineering,Tongji University,Shanghai 200092;State Key Laboratory of Disaster Prevention&Mitigation of Explosion&Impact,Army Engineering University of PLA,Nanjing 210007)

机构地区：[1]同济大学土木工程防灾国家重点实验室,上海200092 [2]同济大学地下建筑与工程系,上海200092 [3]陆军工程大学爆炸冲击防灾减灾国家重点实验室,南京210007

出　　处：《现代隧道技术》2022年第5期41-46,共6页Modern Tunnelling Technology

摘　　要：从隧洞松动圈扩展规律的研究角度出发,采用FLAC 2D软件对四种不同跨度的扁平隧洞进行了变埋深整体式开挖的数值模拟,以极限拉应变准则作为围岩松动圈的判断标准,进行了相应的松动圈扩展规律分析。研究结果表明:(1)四种不同跨度洞室松动圈主要分布在拱部围岩,侧壁没有明显松动,当跨度增加到68 m时,松动圈增幅明显增加;(2)随着隧洞埋深的增加,松动圈的范围呈现先增加后减小再增加的趋势;(3)隧洞跨度的增加,扁平化程度的加剧,导致松动圈减小阶段出现所需的埋深条件增加。四种不同跨度隧洞具有不同的最佳埋置深度,可为实际工程的设计施工提供参考。From the perspective of the expansion law of cavern loosen zone,FLAC 2D software was adopted to carry out the numerical simulation of four different flat caverns with different spans and buried depths.The full-face excavation method was selected to simulate the construction.And the loosened zone of surrounding rock was estimated by the ultimate tensile strain criterion.After that the corresponding expansion pattern of loosened zone was analyzed.The research result shows that:(1)The loosened zone of the four caverns are mainly distributed at the arch part of surrounding rock,and the sidewall is not loose.When the span increases to 68 m,the scale of loosen zone increases significantly.(2)With the increase of buried depth of caverns,the range of loosened zone firstly increases,then decreases and increases again.(3)The increase of span and degree of flattening leads to higher requirement of buried depth for the decreasing stage of loosened zone.Four different caverns have different optimum buried depths,which can provide reference for the design and construction of practical projects.

关 键 词：大跨度 扁平隧洞 极限拉应变 松动圈 数值模拟 

分 类 号：U452[建筑科学—桥梁与隧道工程]