基于Mindlin应力解的超大群桩基础沉降计算  

Settlement Calculation Based on Mindlin Stress Solution for Extra-long Large Diameter Pile Groups Foundation

作　　者：邓友生[1] 龚维明[2] 苏骏[1] 

机构地区：[1]湖北工业大学土木工程与建筑学院,湖北武汉430068 [2]东南大学土木工程学院,江苏南京210096

出　　处：《铁道学报》2009年第1期121-125,共5页Journal of the China Railway Society

基　　金：江苏省交通厅科研项目(04Y029)

摘　　要：针对18根和64根超长大直径群桩基础,采用Mindlin应力解,假定桩端阻力为集中力、桩侧摩擦阻力呈向下线性增加分布形式,推导沉降计算公式。在苏通大桥主塔下实际地基和离心试验模型地基条件下,分别按照应力比和变形比确定压缩土层的计算深度,对这两类超长大直径群桩进行沉降量计算。研究表明,对于超长群桩而言,基于Mindlin应力解,采用变形比法进行沉降计算比较合理;对于桩数不同的群桩,其计算精度也不相同,说明群桩效应对沉降计算有影响;在两类地基条件下,不论按应力比法还是变形比法进行沉降计算,与离心模型试验沉降值相比,其最大差值均不超过10%,说明利用模型地基进行沉降计算是可行的。Based on the Mindlin stress solution, the formulas for settlement of 18-pile and 64-pile extra-long and large diameter pile groups were deduced according to the hypotheses that the resistance to the pile end is the concentrated force and skin friction of the pile is the linear increasing distributed force. Determining calculated depths of compressed soil layers according to the displacement ratio and stress ratio respectively, the settlement of the two types of pile groups was obtained respectively in the condition of foundation soils under the main tower of the Su-tong Bridge and in the condition of model foundation soils in centrifugal tests. The results are as follows： For extra-long and large diameter pile groups, it is rational to calculate settlement with the displacement ratio method on the basis of Mindlin stress solution; for pile groups of different number of piles, the degrees of calculation accuracy are different, showing that pile groups effect have influence on settlement calculation;comparing with centrifugal model tests,the maximum differences of the settlement values are no more than 10% no matter whatever ratio methods are used. So,it is feasible to calculate settlement by model foundation soils.

关 键 词：超长大直径群桩 沉降 MINDLIN应力解 计算 

分 类 号：U443.154[建筑科学—桥梁与隧道工程]