刚性疏桩复合地基桩土荷载分担的实用计算方法

A practical calculating method on load sharing between pile and soil for rigid sparse pile composite foundation

为了合理评估路堤下刚性疏桩复合地基桩、土之间的荷载分担,首先基于单桩分析模型和Marston土压力理论,将上部路堤的土拱效应简化为桩顶上方虚土柱与其周围土的相互作用,建立了路堤荷载传递分析的计算模型;在此基础上,结合复合地基桩体承载机理,考虑基底桩土刚度差异对路堤荷载传递的影响,给出了一种计算刚性疏桩复合地基桩土荷载分担的方法;最后,通过与工程实测结果和其他计算方法结果的对比,对本文计算方法进行了验证,并通过算例分析了桩土荷载分担比随填土高度、填土粘聚力和基底桩土刚度等因素的变化规律。

In order to properly evaluate the load sharing between pile and soil for rigid sparse pile composite foundation under embankment,firstly, based on unite cell model and theory of Marston, the embankment soil arching effect was simplified as the interaction between fictitious soil pile and fill around fietitious soil pile. Then, an analytic model of load transfer in embankment was drawn. On the basis of whieh, considering the bearing mechanism of sparse piles and taking the stiffness difference between sparse piles and soil into account, a new method was presented for pile-soil load share ratio calculation of compensating foundation with sparse piles. Finally ,the present method was validated by comparing analytical solutions with the observed results in an engineering project and the calculated results in references. The factors which affect pile-soil load share ratio, such as the height of embankment, the cohesion of fill and pile-soil stiffness ratio, were systematically analyzed.