地形偏压对连拱隧道支护结构及围岩的影响  

Influence of Terrain Bias on Multi-arch Tunnel Supporting Structure and Surrounding Rock

作　　者：何丹 郭亚林 林宇亮[1] 肖洪波 张沛然 HE Dan;GUO Ya-lin;LIN Yu-liang;XIAO Hong-bo;ZHANG Pei-ran(School of Civil Engineering,Central South University,Changsha,Hunan 410075,China;CCFED Civil Engineering Co.,Ltd.,Changsha,Hunan 410004,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410075 [2]中建五局土木工程有限公司,湖南长沙410004

出　　处：《公路交通科技》2024年第11期167-177,共11页Journal of Highway and Transportation Research and Development

基　　金：国家自然科学基金项目(51878667,51778641);湖南省自然科学基金项目(2021JJ30830,2018JJ2517)。

摘　　要：为研究连拱隧道施工过程中地形偏压对隧道支护结构及周边围岩的影响,掌握连拱隧道施工中的关键工序及控制要点,依托长沙市某偏压连拱隧道工程开展现场试验研究。首先,通过现场试验对围岩压力、初期支护钢拱架轴力、二次衬砌钢筋轴力、拱顶沉降和周边收敛等进行施工全过程动态监测。然后,采用Abaqus建立反映实际工程条件和施工顺序的二维数值分析模型,分别对先开挖浅埋侧洞室和先开挖深埋侧洞室的2种施工方法进行模拟研究。最后,结合现场监测数据和数值模拟结果,对隧道周边围岩及支护结构的内力和变形规律进行分析。结果表明:受地形偏压作用,左洞区域的围岩压力理论值大于实测值约35 kPa,偏压作用明显的位置为右拱肩位置,该处的围岩压力计算值与实测值皆大于左拱肩处约36 kPa;拱肩和拱腰区域钢拱架轴力较大,达到470 kN和407 kN;拱顶和拱脚区域二衬钢筋轴力较大,分别达到23.31 kN和16.46 kN,且二衬钢筋轴力沿中隔墙对称分布;隧道埋深越深,拱顶沉降值越小;以中隔墙为对称轴,除外侧测点外,左洞室各对应测点沉降值均大于右洞室5%~6%。对于偏压连拱隧道,先开挖深埋侧洞室有利于控制支护结构的变形与受力,保证结构稳定性。To study the influence of terrain bias on the multi-arch tunnel supporting structure and surrounding rock during construction,and to obtain the key steps and control points of construction process,the field test was carried out based on a biased multi-arch tunnel project in Changsha city.First,the dynamic monitoring during whole construction process was carried out in terms of the surrounding rock pressure,the axial force of initial supporting steel arch,the axial force of second lining steel,the vault settlement,and the surrounding rock convergence.Meanwhile,the two-dimensional numerical analysis model,considering the actual engineering condition and construction sequence,was established by using Abaqus to simulate the two construction schemes of excavating the shallow buried side chamber first,and excavating the deep buried side chamber first.Finally,the internal force and deformation rule of surrounding rock and tunnel supporting structure were analyzed by combining the field monitoring data and numerical simulation results.The result indicates that the theoretical value of surrounding rock pressure in the left chamber area is about 35 kPa greater than the measured value subject to topographic deviation.The obvious deviation location is the right arch shoulder,where the theoretical and measured values of surrounding rock pressure are about 36 kPa greater than those at the left arch shoulder.The large values of steel arch frame axial force are observed at the shoulder and waist areas,which are 470 kN and 407 kN.The axial force of second lining reinforcement at the top and foot areas are large,reaching 23.31 kN and 16.46 kN.The axial force of second lining reinforcement are symmetrically distributed along the middle diaphragm.The deeper the tunnel is buried,the smaller the settlement value will be.Taking the middle diaphragm wall as the symmetry axis,except for the outer measurement points,the settlement value of each corresponding measurement point in the left chamber is greater than that of the right chamber b

关 键 词：隧道工程 偏压 现场试验 数值模拟 连拱隧道 支护结构内力 围岩变形 

分 类 号：U452.27[建筑科学—桥梁与隧道工程]