考虑隧道开挖与桩基相互作用的大底盘塔楼建筑变形分析

Analysis on deformation of tower with large chassis considering interaction between tunnel excavation and pile foundation

采用两阶段分析方法研究隧道开挖与大底盘塔楼建筑桩基相互作用对大底盘塔楼结构的影响.首先,计算出隧道开挖诱发的地层位移和附加荷载;然后,采用子结构刚度凝聚法将上部大底盘塔楼建筑刚度凝聚至下部桩基础,得到大底盘塔楼结构的内力及变形.建立上部结构形式为大底盘塔楼结构和普通梁结构的2种计算模型,基于桩基数量、隧道埋深及隧道水平位置,对其上凸与下凹变形进行分析.结果表明,当隧道埋深与桩长之比小于2.5时,宜采用大底盘塔楼结构模型计算;当隧道埋深与桩长之比大于2.5时,宜采用梁结构模型计算.当隧道处于不同水平位置时,大底盘塔楼结构模型的上凸下凹变形均小于梁结构模型变形.桩基数量对梁结构、大底盘塔楼结构模型上凸下凹变形影响最弱.

A two-stage method was used to investigate the influence of the interaction between tunnel excavation and pile foundation on the structure of a tower with large chassis.Firstly,the ground displacement and the additional load induced by tunnel excavation were calculated.Then,by the substructure stiffness cohesion method,the structural rigidity of the upper large chassis tower was condensed to the pile foundation.The internal force and deformation of the tower with large chassis were obtained.Two models for the large chassis tower structure and the beam structure were established according to the superstructure form.The hog and sag deformations of the large chassis tower structure model and the beam structure model were analyzed based on the number of piles,the depth of the tunnel and the horizontal position of the tunnel.The results show that when the ratio of the buried depth of the tunnel to the pile length is less than 2.5,the large chassis tower structure model is suitable for calculation.When the ratio of the buried depth of the tunnel to the pile length is more than 2.5,the beam structure model should be used.When the tunnel is at different horizontal positions,the hog and sag deformation of the large chassis tower structural model is smaller than that of the beam structure model.The number of the piles has the weakest influence on the hog and sag deformations of the beam model and the large chassis tower model.