水平荷载作用下高承台管桩的荷载传递性状及承载力研究

Load Transfer and Bearing Capacity of High-Cap Pipe Piles under Horizontal Load

土地资源紧缺使得在地基回填基料缺乏的天津沿海港区建设中,首次采用了部分桩体"悬空"的高承台管桩基础,如何确定这些悬空管桩的水平抗力特性是工程实践应用中的难题之一。针对天津东疆保税港区物流加工区二期工程所采用的高承台管桩基础,运用有限元分析软件ABAQUS对水平荷载作用下高承台管桩的受力性状进行模拟。分析了不同桩长、不同桩径、不同桩身弹性模量、不同土质条件下以及不同悬空高度下高承台管桩的荷载传递性状及承载力的变化规律,并与低承台管桩受力性状进行比较。有限元分析结果表明,当悬空高度不大于1.7m时,高承台管桩水平极限承载力变化不大,而当悬空高度超过1.7m时,其承载力迅速减小。增加土体强度、桩身模量和桩径有助于提高高承台管桩水平极限承载力,桩长对其影响不大。

High cap pipe piles partly exposed in the air were firstly used in the construction of Tiaujin coastal port, where the short of land resources made backfill soils in short supply. How to ascertain the horizontal resistance characteristic of these pipe piles was a challenge in engineering practice. Given the strong correlation between the structural design and the lateral load transfer properties, as well as foundation anti-bending capacity and the overall Stability, the force character research on high cap pipe piles under lateral load, which are firstly used in the second phase project of Tiaujin Baoshui Port district, is presented through ABAQUS in this paper. The numerical simulation analysis of high cap pipe piles under lateral load in different pile lengths, diameters, elastic modules, sorts of soils and different exposing heights, is carried out firstly, then this result is compared with low cap pipe piles. Eventually, the force characters of high cap pipe piles under lateral load are obtained through the numerical analysis. When the exposing height is less than 1.7 m, ultimate horizontal bearing capacity of high cap pipe piles stays constantly; when the exposing height is more than 1.7 m, it decreases rapidly. Increasing the soil strength,the modulus and diameter of piles could be favorable to the horizontal bearing capacity, while changing the length has little influence.