摘要
针对隧道工程中新建隧道小角度斜下穿既有隧道工程中亟待解决的难题,以西安地铁1号线二期张家村-后卫寨区间左线盾构下穿既有1号线出入段线为工程依托,通过现场调研、数值模拟和现场监测等方法进行施工参数对轨道既有隧道和轨道高差的沉降规律(重点进行对轨道高差的控制)研究。选取土仓压力、注浆压力、注浆量等施工参数,其中注浆量用注浆厚度间接体现,构建三维数值计算模型,并对结果进行分析,依据分析结果给出合理的盾构施工参数建议值,在此基础上进行现场监测,验证给出的施工参数建议值对轨道高差的控制效果。研究结果表明:随着土仓压力、注浆压力的增大,既有隧道的沉降和轨道高差不断减小,当其土仓压力超过0.10 MPa、注浆压力超过0.22 MPa时,既有隧道沉降和轨道高差控制效果不再明显提高;既有隧道沉降和轨道高差随着注浆厚度的增大而减小,其与注浆厚度均近似呈线性关系,因此适当增大注浆范围是控制既有隧道沉降和轨道高差的有效方法;确定的施工参数建议值为0.10 MPa(土仓压力)+0.22 MPa(注浆压力)+0.23 m(注浆厚度);通过现场监测,既有地铁隧道道床上C,B,G,F四条测线上最大沉降量均在6 mm左右(小于20 mm),最大轨道高差为1.2 mm(小于4 mm),均小于规范所要求的控制值,表明以上施工参数建议值对于既有隧道沉降和轨道高差起到了很好控制效果。
New tunnels that closely undercross existing tunnels at small angles cause problems that need to be solved. The left line of the shield tunnel section that starts from Zhangjiacun station to Houweizhai station in the Xi＇an Metro Line 1 is constructed in close proximity to the existing Line 1 above it. Thus, field investigations, numerical simulation, and field monitoring were used to analyze the influence of construction parameters on the settlement and distance between two tracks of the existing tunnels. This study chose the construction parameters to be soil pressure, grouting pressure, and grouting amount, and the grouting amount was indirectly measured through grouting thickness. A three-dimensional numerical simulation model was constructed. By analyzing the results of the simulation, reasonable values of shield construction parameters were obtained. Field monitoring was carried out to verify the control effect of the proposed construction parameters on the track height difference. The results show that with the increase of chamber pressure and grouting pressure, both the settlement of existing metro tunnels and the distance between two tracks will continue to decrease; however, when the chamber pressure increases to 0.10 MPa and grouting pressure increases to 0.22 MPa, the control effects are no longer significantly improved. Therefore, the settlement of existing lines and the distance between two tracks decrease with the increase of the grouting thickness, which shows an approximately linear relationship. Thus, increasing the grouting range is an effective method to control the settlement and orbital difference of existing tunnels. From the numerical simulations, the recommended values of the construction parameters are 0.10 MPa for chamber pressure, ＋0.22 MPa for grouting pressure, and ＋0.23 m for grouting thickness. Through field monitoring, on the existing subway tunnel bed, the maximum settlement of the four measured lines C, B, G, and F are found to be approximately 6 mm, less than 20 mm, and the maximum rail height difference is 1.2 mm, less than 4 mm. These are all seen to be less than the control values required by the specifications, indicating that the suggested construction parameters have a good control effect on the existing tunnel settlement and rail height difference.
作者
来弘鹏
郑海伟
何秋敏
刘海洋
LAI Hong-peng;ZHENG Hai-wei;HE Qiu-min;LIU Hai-yang(Key Laboratory for Bridge and Tunnel of Shaanxi Province,Chang＇an University,Xi＇an 710064,Shaanxi,China;T.Y.LIN International Engineering Consulting China Co.,Ltd.,Chongqing 401121,China;Xi＇an Youheng Real Estate Development Co.,Ltd.,Xi＇an 710004,Shaanxi,China)
出处
《中国公路学报》
EI
CAS
CSCD
北大核心
2018年第10期130-140,共11页
China Journal of Highway and Transport
基金
国家自然科学基金项目(51378071)
陕西省自然科学基金项目(2014KJXX-53
2014SZS19-Z01)
西安市地下铁道有限公司科技项目(D4-YJ-042014049)
国家留学基金项目(201206565026)
关键词
隧道工程
施工参数
现场监测
数值模拟
小角度下穿
tunnel engineering
construction parameters
field monitoring
numerical simulation undercrossing at small angle
