铁路车站隧道下穿桩基工程设计与分析

Design and Analysis of the Tunnel Section at Railway Station Crossing under the Pile Foundation

以贵阳铁路枢纽龙洞堡机场车站隧道大跨段下穿机场高架桥工程为依托,采用理论分析、数值模拟和现场实测手段,基于岩体冲切破坏锥体理论,提出了满足桩基受力的最小岩板厚度确定方法;建立了考虑隧道开挖围岩扰动范围和桩基础冲切破坏范围的隧道-桩基近接关系划分标准;提出了高架桥沉降控制标准和设计对策,并采用现场实测数据进行验证。结果表明:隧道下穿桩基工程影响分区划分合理,设计对策有效控制了隧道开挖对高架桥的影响,同时桩基础对隧道的影响可控。

Based on the case of the Large-span Tunnel Section at Longdongbao Airport Station(Guiyang Railway Hub) crossing under the airport viaduct and the theory of punching shear failure cone of rock mass, the method for determining the minimum rock slab thickness that meets the pile foundation stress requirement was put forward by using theoretical analysis, numerical simulation and field measurement;the standard for dividing the tunnel-pile foundation proximity relationship was established, in which the surrounding rock disturbance range of tunnel excavation and the range of punching shear failure of pile foundation were considered;and the viaduct settlement control standard and design countermeasures were proposed and the measured data were used for verification. The results show that the zone of influence of the tunnel crossing under the file foundation is reasonably divided, the design countermeasures can effectively control the impact of tunnel excavation on the viaduct, and meanwhile, the impact of pile foundation on the tunnel can be controlled.