超大跨度变断面隧道围岩力学动态响应与开挖步序优化数值模拟研究——以苏州七子山隧道为例  

Study on the Dynamic Response of Rock Mechanics and Numerical Simulation of ExcavationSequence Optimization in Ultra-large Span Variable Section Tunnels: Taking SuzhouChangjiang Road South Extension Project-Qizishan Tunnel Project as an Example

作　　者：赵虎 张恭禄 李世堂 刘禹 任相利 孔令威 王瑞 邱德才 张合鑫 ZHAO Hu;ZHANG Gonglu;LI Shitang;LIU Yu;REN Xiangli;KONG Lingwei;WANG Rui;QIU Decai;ZHANG Hexin(Shandong Road and Bridge Group Co.,Ltd.,Jinan 250014,China;College of Civil Engineering and Architecture,Shandong University of Science and Technology,Qingdao 266590,Shandong,China;Shandong China Construction Eighth Bureau Investment and Construction Co.,Ltd.,Jinan 250031,China)

机构地区：[1]山东省路桥集团有限公司,济南250014 [2]山东科技大学土木工程与建筑学院,山东青岛266590 [3]山东中建八局投资建设有限公司,济南250031

出　　处：《科技和产业》2024年第9期227-238,共12页Science Technology and Industry

基　　金：山东省高等学校青年创新团队计划基金(2022KJ214)。

摘　　要：保证超大跨度变断面隧道的施工安全,同时兼顾施工便利性及施工效率,具有重要意义。依托苏州长江路南延工程-七子山隧道工程,针对连拱转大跨段开挖过程中拆除或保留临时支撑,以及超大跨度段的是否调整优化开挖步序这两种工况,采用FLAC3D开展数值模拟研究,从围岩位移和围岩应力两方面进行对比分析。研究结果表明:以上两种工况下,围岩位移和围岩应力均存在明显差异;在连拱转大跨段,开挖过程中保留临时支撑围岩所受扰动更小,围岩应力变化较小;在超大跨度段,开挖步序优化方法的拱顶最终沉降值减小了8.60%,仰拱最终隆起值减小了4.01%,左边墙和右边墙最终水平收敛值分别减小了9.42%和16.70%,且优化方法的各测点围岩应力变化相对较小。根据得到的对比分析结果对现场施工提出优化建议:对连拱转大跨段,随开挖过程保留临时支撑,同时为保证施工便利性,采用门式拱架作为临时支护手段;对超大跨度段,采用优化的开挖步序进行施工,可进一步降低围岩扰动,提高施工安全。In order to ensure the construction safety of the super large-span variable cross-section tunnel,while considering the construction convenience and efficiency.Taking Suzhou Changjiang Road South Extension Project-Qizishan Tunnel Project as an example,the excavation process of continuous arch to large-span section was studied by using FLAC3D numerical simulation in two working conditions:whether to remove or retain temporary support during excavation,and whether to adjust and optimize the excavation sequence of the super large-span section.Comparative analysis was conducted from the perspectives of surrounding rock displacement and stress.The results show that there are significant differences in surrounding rock displacement and stress under the two working conditions mentioned above.In the continuous arch to large-span section,the surrounding rock disturbance is smaller and the surrounding rock stress changes less when temporary support is retained during the excavation process.In the super large-span section,the optimized excavation sequence method reduces the final settlement value of the arch crown by 8.60%,reduces the final uplift value of the arch spring line by 4.01%,reduces the final horizontal convergence values of the left and right side walls by 9.42%and 16.70%respectively,and the optimized method results in relatively small changes in stress of the surrounding rock at various measuring points.Based on the comparative analysis results,optimization suggestions are proposed for on-site construction:for the continuous arch to large-span section,retain temporary support during excavation and use a gantry arch frame as a temporary support method to ensure construction convenience,for the super large-span section,adopt optimized excavation sequence for construction to further reduce surrounding rock disturbance and improve construction safety.

关 键 词：超大跨度变断面隧道施工 数值模拟 FLAC3D 施工工法优化 

分 类 号：U451[建筑科学—桥梁与隧道工程]