盾构隧道侧穿高架桥对桩基的影响分析

Analysis of the Influence of Shield Tunnel Side Crossing Viaduct on Pile Foundation

福州地铁5号线一期工程多次穿越长桩基群,具有扰动多、距离近、受力情况复杂等特点。为进一步研究盾构隧道侧穿高架桥对桩基的影响,采用数值模拟手段,对施工前后的桩基群进行了结构内力和变形特征分析,并进一步研究了不同地层损失率对桩基群受力和变形的影响。结果表明:桥梁下的桩基可以减少地表的沉降范围和沉降程度;桩基的变形和受力主要受到埋深和桩隧间距的影响;地层损失率越大,桩基的最大水平位移和桩基两端竖直位移的差值越大,桩基所受最大轴力和最大弯矩也越大;当地层损失率在特定范围内时,地层损失率每增加0.1%,桩基最大水平位移大约增长1 mm,桩基所受最大弯矩大约增长93 kN·m。研究结果为类似工程开展相关工作提供了一定参考。

Based on the repeated crossing of long pile foundation groups by line 5 of Fuzhou metro shield tunnel,this paper analyzes the structural internal forces and deformation characteristics of the pile foundation groups after the shield tunnel is crossed by three-dimensional numerical simulation methods,and further studies the influence of different ground loss ratios on the force and deformation of pile foundation groups.The results show that the pile foundation under the bridge can reduce the settlement range and settlement degree of the surface.The deformation and force of the pile foundation are mainly affected by the burial depth and the spacing between the pile tunnel.Moreover,the greater the ground loss ratio,the greater the difference between the maximum horizontal displacement of the pile foundation and the vertical displacement at both ends of the pile foundation and the greater the maximum axial force and bending moment of the pile foundation.When the ground loss ratio is in the certain range,the maximum horizontal displacement of the pile foundation increases by about 1 mm for every 0.1%of the ground loss ratio,the maximum bending moment of the pile foundation increases by approximately 93 kN·m.Therefore,it could provide references for other similar projects.