单洞四车道超大跨度公路隧道Ⅳ级围岩合理施工方法研究  

Reasonable Construction Method for GradeⅣSurrounding Rock in Single-Hole Four-Lane Super-Span Highway Tunnel

作　　者：李合银 高景明 李炎峰 荀文杰 董方方 张建刚 LI Heyin;GAO Jingming;LI Yanfeng;XUN Wenjie;DONG Fangfang;ZHANG Jiangang(CCCC-SHB Fourth Engineering Co.,Ltd.,Luoyang,Henan 471013,China;School of Highway,Chang’an University,Xi’an,Shaanxi 710064,China)

机构地区：[1]中交二公局第四工程有限公司,河南洛阳471013 [2]长安大学公路学院,陕西西安710064

出　　处：《中外公路》2024年第2期220-230,共11页Journal of China & Foreign Highway

基　　金：国家自然科学基金资助项目(编号:51978065)。

摘　　要：为研究超大跨度公路隧道的合理施工方法,该文以连霍高速公路新疆境内小草湖至乌鲁木齐段改扩建工程杏花村1号隧道为依托,通过数值模拟方法对超大跨度公路隧道Ⅳ级围岩采用CD法、上台阶CD法和三台阶七步开挖法施工的隧道变形和支护结构受力情况进行分析,在变形与支护结构受力满足设计要求的前提下,考虑各施工方法的优缺点等因素,确定最合理的施工方法,通过开展现场试验分析施工方法的可行性。结果表明:①CD法、上台阶CD法和三台阶七步开挖法数值计算的隧道变形均不大于21 mm,初期支护安全系数分别为2.48、2.41、2.28,大于隧道设计细则要求的最小安全系数,变形与支护结构受力均满足设计要求;②对比3种工法的优缺点,结合隧道地质条件等因素,确定杏花村1号隧道Ⅳ级围岩最优施工方法为上台阶CD法;③根据现场测试结果,Ⅳ级围岩采用上台阶CD法施工,拱部下沉最大值为14.6 mm,周边位移最大值为15.0 mm,隧道变形控制效果较好;初期支护的最小安全系数为6.94,满足设计要求。In order to study the reasonable construction method of super-span highway tunnels,the Xinghuacun No.1 tunnel included in the reconstruction and expansion project of the Xiaocaohu–Urumqi section of the Lianyungang–Khorgos Expressway in Xinjiang was studied.The numerical simulation method was used to analyze the deformation and stress of the supporting structure of the Grade tisurrounding rock in the super-span highway tunnel constructed by the center diaphragm(CD)method,the upper-bench CD method,and the threebench and seven-step excavation method.Under the premise that the deformation and the stress of the supporting structure met the design requirements,the advantages and disadvantages of each construction method were considered,and the most reasonable construction method was determined.The field test was implemented to analyze the feasibility of the construction method.The results show that:①The tunnel deformation calculated by the CD method,the upper-bench CD method,and the three-bench and seven-step excavation method are all less than 21 mm,and the safety factors of the supporting structure at the initial stage are 2.48,2.41,and 2.28,respectively,which are greater than the minimum safety factor required by the tunnel design rules.The deformation and the stress of the supporting structure all meet the design requirements;②the advantages and disadvantages of the three construction methods are compared,and the optimal construction method for the gradeⅣsurrounding rock in the Xinghuacun No.1 tunnel is determined as the upper-bench CD method after considering tunnel geological conditions and other factors;③according to the field test results,the gradeⅣsurrounding rock is constructed by the upper-bench CD method.The maximum arch subsidence is 14.6 mm,and the maximum peripheral displacement is 15.0 mm,indicating a good tunnel deformation control effect.The minimum safety factor of the supporting structure at the initial stage is 6.94,which meets the design requirements.

关 键 词：隧道工程 超大跨度公路隧道 合理施工方法 CD法 上台阶CD法 

分 类 号：U455.4[建筑科学—桥梁与隧道工程]