盾构始发即斜交下穿高速公路路基填石边坡专项设计研究

Research on Specialized Design of Shield Originating and Undercrossing by Highway Rockfill Subgrade Slope

以东莞市城市轨道交通1号线一期工程黄牛埔站~黄江中心站区间隧道为依托,研究了双线盾构始发即小角度下穿高速公路填石路基及路基边坡的专项设计。并基于数值模拟及现场监测数据验证,得出结论:设置大管棚隔离层切断盾构下穿与路基路面应力传递路径,可有效控制盾构下穿填石路基过程的路面沉降;盾构下穿过程中的掘进参数控制,对路基沉降起主导作用是土仓压力、注浆压力两个参数,应特别注意结合监测数据进行调整;沉降敏感地段,宜适当放慢盾构掘进速度、匀速掘进,尽量减小对土体的扰动。此次盾构小角度下穿高速公路填石路基及路基边坡专项设计的相关工程措施,满足路面沉降限制要求,确保了莞深高速在盾构下穿过程的安全运营,可对类似工程提供参考和借鉴。

Based on Huangniupu Station-Huangjiang Central Station running tunnel of Phase I project of Dongguan Rail Transit Line 1,this paper studies the specialized design for shield originating and undercrossing at small angle by a double-track metro shield tunnel in highway rockfill subgrade or roadbed slope.Based on the numerical simulation and on-site monitoring data validation,conclusions are drawn as follows:setting a large pipe roof isolation layer to cut off the stress transfer path between the shield undercrossing and the subgrade and pavement,which can effectively control the pavement settlement during the process of the shield undercrossing the rockfill subgrade;the control of excavation parameters during the process of down-traversing shield tunnel plays a dominant role in the roadbed subsidence.Special attention should be paid to adjusting parameters of chamber earth pressure and grouting pressure in combination with monitoring data.In settlement sensitive areas,the excavation speed of shield tunneling should be appropriately slowed down and uniformly excavated to minimize disturbance to the soil as much as possible.The engineering measures meet the requirements for road settlement limitation,ensure the safe operation of the Guanshen Expressway during the process of down-traversing shield tunnel,and can provide reference for similar projects.