地铁盾构下穿高速公路的路面变形特征分析

盾构施工过程中由于土体挖除、管片和二衬设置,将在穿越过程引起高速公路路面的沉降或隆起,对公路正常运营产生不利影响。论文采用Midas/GTS软件建立了北京地铁7号线盾构下穿京哈高速公路施工过程有限元模型,分析采用盾构法先后施工左右线隧道引起的高速公路路面变形特征,认为地铁盾构掘进过程中,公路路面沉降变形在纵向呈现出抛物线形态,在横向上沉降槽呈现为"U"形,最终的路面最大沉降值产生在两线隧道中轴线上方的右线第10掘进段(第23施工步)开挖时,最大值为15 mm,路面最大隆起值出现在右线上方的右线第9掘进段(第22施工步)开挖时,达6 mm。

Feature Analysis of Express Highway Pavement's Deformation Caused by Metro Shield Tunneling under the Express Highway

In the process of shield tunneling,due to soil excavation,pipe segment and secondary-lining setting up,the phenomena of settlement or upheaval of express highway pavement will be induced especially during the shield machine crossing under this express highway,adversely affecting the normal operation of this express highway.This paper,by using Midas/GTS software,establishes finite element model of the construction process of the Beijing Metro Line 7 with shield method crossing under the Beijing-Haerbin Express Highway,and then analyzes the features of the express highway pavement's deformations which are caused by the constructions of the left and the right tunnel lines one after another with shield method.It is concluded that: in the process of shield tunneling,the settlement of express highway pavement presents the parabola shape along the longitudinal direction,while it presents an 'U' shape along the transverse direction.The finally maximum settlement value of the pavement is 15mm which appears during the excavation of the 10# tunneling section(the 23rd construction step) at the right line of up direction of central axis of the two tunnel lines,while the maximum upheaval value is 6mm which appears during the excavation of 9# tunneling section(the 22nd construction step) at the right line of up direction of the right line.