顶管施工对高架桥桩基础影响的数值分析

顶管施工广泛应用于市政工程的隧道开挖作业.针对某地下电缆隧道穿越高架桥桩基的实际工程案例,利用数值模拟方法建立有限元计算模型,研究了沉井和顶管施工对附近土体的扰动以及高架桥桩基的变形、受力等情况.结果表明,沉井和顶管施工会对周围桩基础的应力和变形产生一定影响.在外径12.8 m的沉井施工时,施工引起的土体卸载会使得沉井...

Numerical Analysis of the Influence of Pipe Jacking Construction on Pile Foundation of Viaduct

Pipe jacking is widely used in tunnel excavation of municipal works. However, the influence of pipe jacking on surrounding structures still needs to be further studied. Based on the pipe jacking process of a cable tunnel in Tianjin, the finite element calculation model of caisson and pipe jacking construction near the pile foundation of viaduct is established. The deformation of soil and the deformation and stress of pile foundation are studied. Results show that both the construction process of open caisson and pipe jacking will have an impact on the stress and deformation of the pile foundation. During the construction of open caisson of which external diameter is 12.8 m, soil unloading caused by open caisson will cause large uplift of soil around open caisson and the maximum value is about 164 mm. The maximum deformations in three directions including horizontal and vertical directions occur in the surrounding soil of the caisson. This process will also have a certain impact on the pile foundation which is 30 meters away from the caisson. The pile is greatly affected in X direction pointing to open caisson. The upper part of the pile will generate a horizontal displacement away from the caisson and the deeper part will get close to the caisson. The maximum displacement in X direction is about 1.6 mm. This process has little effect on the horizontal displacement in Y direction which is perpendicular to pipe jacking. In the process of pipe jacking of which external diameter is 3.6 m, the soil will produce a deformation due to unloading and the maximum displacement is 170 mm. The displacement occurs in the disturbed soil which is below the pipe jacking. In X direction, all the four piles generate a horizontal displacement away from the caisson at the pile cap and the piles deform close to the caisson at bottom. In Y direction, the maximum horizontal displacement of pile occurs at the depth of tunnel excavation and the displacement is away from the pipe jacking. The range of influence is 15 m around the construction site of pipe jacking tunnel.