预钻根植竹节桩的抗压承载特性研究

Study on Compressive Bearing Characteristics of Pre-Drilled Rooted Nodular Pile

预钻根植竹节桩是近年来出现的一种新型组合桩基,由预制桩和水泥土组合而成。相比传统预制桩和钻孔灌注桩,具有承载力高、经济环保、技术含量高、桩身质量好等优点,目前在宁波、上海等地有了一些初步的工程应用,然而国内对预钻根植竹节桩竖向抗压承载特性的相关研究较少。本文通过现场实测数据,获得工程试验桩的最大竖向试验静载荷,并通过指数函数拟合,预测各桩的极限抗压承载力;基于ABAQUS软件建立预钻根植竹节桩三维模型,研究不同桩端扩大头扩径率对桩基单桩抗压承载特性的影响,并得出结论:预钻根植桩桩端扩径率越大,桩基极限承载力越高,桩端承载变形性能越好。本研究立足于当前预钻根植桩的工程应用需求,为根植桩设计和施工提供理论和技术支撑。

The pre-drilled rooted nodular pile is a new type of composite pile foundation appeared in recent years,which is composed of precast piles and cement-soil.Compared with traditional precast piles and bored piles,it has the advantages of high bearing capacity,economic and environmental protection,high technical content and good pile body quality,and has some preliminary engineering applications in Ningbo,Shanghai and other places.However,there are few related studies on the vertical compressive bearing characteristics of pre-drilled rooted nodular pile.In this paper,the maximum vertical test static load of the engineering test pile was obtained through the field measured data,and through exponential function fitting,the ultimate compressive bearing capacity of each pile was predicted;at the same time,a three-dimensional model of the pre-drilled rooted nodular pile was established based on the ABAQUS software to study the influence of different expansion rates of the pile end enlarged head on the compressive bearing characteristics of single piles.It is concluded that the larger the diameter expansion rate of the pre-drilled rooted pile,the higher the ultimate bearing capacity of the pile foundation,and the better the bearing deformation performance of the pile tip.Based on the current engineering application requirements of pre-drilled rooted piles,this research provides theoretical and technical support for the design and construction of rooted piles.