由单桩载荷试验推算群桩沉降的相互作用系数法  

Interaction factor method for piles group settlement by static load tests of single pile

作　　者：林智勇[1,2] 戴自航[2,3] 

机构地区：[1]福建工程学院土木工程学院,福建福州350118 [2]福州大学岩土工程研究所,福建福州350108 [3]卧龙岗大学土木采矿与环境工程学院

出　　处：《岩土工程学报》2016年第1期155-162,共8页Chinese Journal of Geotechnical Engineering

摘　　要：传统的相互作用系数法只能计算群桩的弹性沉降,且所得相互作用系数也明显偏大。采用三维数值方法拟合单桩荷载–沉降曲线,通过弹性及弹塑性分析确定土的弹性参数和桩–土弹塑性接触面参数;由此建立双桩模型,计算分析了桩顶荷载水平、桩距径比、桩端土–桩周土模量比、桩–土模量比、桩长径比、桩–桩之间存在第三桩等因素对相互作用系数的影响,并利用多项式回归拟合;根据数值分析及实测结果,提出了在相互作用系数法中利用单桩载荷曲线分析群桩线弹性和非线性沉降的方法,将相互作用系数法扩展至群桩沉降的非线性计算上。算例分析表明:计算结果与实测值吻合较好;较常规的数值模拟,节省了大量的运算机时,可用于大规模的较大桩距桩筏基础的分析计算。In the traditional interaction factor method, only the elastic settlement of pile groups can be calculated, and the interaction factors are significantly greater than the real results. Using 3D numerical simulation method to fit the the load-settlement curve of a single pile, the elastic parameters of soil and pile-soil interface parameters are determined through the elastic and elasto-plastic analyses. Then by establishing a two-pile model, the influences of various parameters such as the load level on pile top, ratio of pile spacing to pile diameter, modulus ratio of pile to soil, modulus ratio of pile tip soil to surrounding soil, pile slenderness ratio and existence of the third pile between two piles on the interaction factors are analyzed, and a polynomial curve is used to fit the results. Based on the results of numerical analysis and field tests, a method using single pile load tests to calculate the elastic and elasto-plastic settlement of pile groups in the interaction factor method is proposed, and it is extended to compute the nonlinear settlement of pile groups. Analysis of an engineering case shows that the load-settlement curve computed by the proposed method agrees well with the measured one, and the proposed method can save a lot of computing time than the conventional numerical simulation and is suitable for the analysis and design of large-scale piled raft foundation with large pile spacings.

关 键 词：单桩载荷试验 相互作用系数 三维数值分析 群桩沉降 

分 类 号：TU473[建筑科学—结构工程]