地铁车站风道洞桩法施工对地层沉降的影响

以北京地铁8号线某区间站PBA(洞桩法)工法施工为背景,通过FLAC3D数值模拟软件对小导洞开挖顺序进行模拟,得到其最优的施工方案。模拟结果表明:优先施工下层导洞的方案三和方案四产生的地表沉降和拱顶沉降小于优先施工上层导洞的方案一和方案二;同层导洞不同的施工顺序也会对地表沉降和拱顶沉降产生不同的影响。最后通过四个施工方案产生的地表沉降和小导洞拱顶沉降的对比,确定采用方案三进行施工。方案三模拟数值与现场监测数值比对结果表明,二者沉降趋势和沉降量都相差不大,验证了模拟结果的可靠性。

Influence of Pile-Beam-Arch Method on Metro Station Ground Settlement

Based on the PBA construction method of an interval station on Beijing metro Line 8,FLAC3D numerical simulation software is used to simulate the excavating sequence of pilot tunnels,an optimized construction scheme is obtained.The simulation results show that the ground settlement and crown settlement caused by the constructions of lower pilot tunnel in scheme 3 and scheme 4 are less than that by the constructions of upper pilot tunnel in scheme 1 and scheme 2,different construction sequences in the same layer pilot tunnel also result in different impacts on ground settlement and crown settlement.Finally,based on a comparison between ground settlement and crown settlement of pilot tunnels in four construction schemes,scheme 3 is chosen to execute construction.A comparison between the simulation data of scheme 3 and the field monitoring data shows,the ground settlement and crown settlement in both cases are not very different,which verifies the simulation reliability of scheme 3.