临海漫滩回填堆载对临近桩基的影响分析

Influence of Surcharge Load on the Adjacent Pile Foundation in Coastal Floodplain

软土地基地面堆载会引起地基土压缩和侧向位移,土体的侧移又会进一步导致临近桩基承载性能发生改变。为了考察沿海漫滩回填堆载导致的地基软弱土压缩和侧向移动作用下的临近既有桩基受力性状,采用有限元分析软件ABAQUS建立了堆载作用下临近桩基的三维有限元模型,分析了堆载作用下软弱地基土的变形运移规律,研究了临近堆载单排桩、双排桩在堆载荷载大小与作用位置、桩身刚度、桩顶约束条件等工况中的性状。结果表明,堆载作用位置越近、荷载水平越高,桩身变形受力响应越明显;桩身刚度的提高会增加被动受荷影响范围;不同桩顶承台约束下桩身变形受力性状差异显著,且桩身轴力引起的“二次弯矩”效应明显,不容忽视。当基底软弱土较厚时,采用水泥搅拌桩加固有利于改善临近桩基变形受力性状。

The surcharge load on soft ground will cause the compression and horizontal displacement of the ground soil,and this horizontal displacement will further lead to the change of the bearing performance of adjacent pile foundation.In order to investigate the behavior of existing piles caused by the horizontal and compression deformation of soft sub-stratum due to backfill surcharge on coastal floodplain,finite element analysis software ABAQUS was used and three-dimensional finite element model of pile adjacent to surcharge load was established.The deformation and migration law of soft soil was analyzed.The behavior of single pile and double row pile adjacent to surcharge load were studied,in which the influence of surcharge load location,surcharge pressure,pile stiffness,and pile top constraint conditions were considered.The results show that as the position of surcharge load is closer and the surcharge pressure increases,the response(e.g.deformation and bending moment)is more obvious.With the increase of pile stiffness,the range of passive load is increased.The deformation behavior of pile body under different constraints of pile cap is significantly different.The effects of secondary bending moment caused by pile axial force is obvious and cannot be ignored.If there is a thick soft substratum,it is beneficial to improve the behavior of adjacent piles by using cement mixing pile reinforcement.