管桩承载性状的数学描述  

MATHEMATIC DESCRIPTION OF BEARING BEHAVIOR OF PIPE PILES

作　　者：蒋建平[1] 

机构地区：[1]上海海事大学交通运输学院,上海200135

出　　处：《工程力学》2008年第5期189-195,209,共8页Engineering Mechanics

基　　金：上海市教委科研项目(05FZ03);上海市教委交通运输与规划重点学科项目(J50601)

摘　　要：基于5根桩现场试验资料的分析,对表征管桩承载性状的桩顶荷载-桩顶沉降曲线、桩身压缩-桩顶荷载曲线进行了数学描述。结果表明:1)用Boltzmann数学模型拟合5根桩的桩顶荷载-桩顶沉降曲线,效果很好,相关系数都达到了0.996以上。2)从综合系数-桩顶荷载曲线图上可发现5根桩的曲线形状有3种类型。3根短桩的综合系数大,2根超长桩的综合系数小。这些反映出综合系数是一个变量而非常数,要由它来确定桩身压缩难度较大。3)用Boltzmann数学模型对桩身压缩-桩顶荷载关系曲线进行回归拟合,效果也很好,各单桩的相关系数都达到了0.996以上,5根桩的综合相关系数为0.9871。这样就可根据已有试桩资料的回归拟合曲线及其方程式来预测和计算该场地及其类似场地中钢管桩的桩身压缩。4)Boltzmann数学模型是适合描述钢管桩桩顶荷载-桩顶沉降、桩身压缩-桩顶荷载这两类曲线的,它为桩身压缩及其极限值的预测、为桩顶极限承载力的判定提供了新方法。5)极限荷载与长径比成大致的负线性关系。Based on the field tests data of five pipe piles, this paper studies mathematically the relationship between pile peak loads and pile peak settlement, as well as the bearing behavior of steel pipe piles in terms of the relationship between pile shaft compression and pile peak loads. Analyzing results are presented in form of curves, and the following conclusions can be drawn. Firstly, Boltzmann model can be use to model the bearing behavior of steel pipe piles, with the eorrelativity coefficient being over 0.996. Secondly, curves of eompositive coefficient versus pile peak loads fall in three types. The eompositive coefficients of three short piles are bigger than those of two super-long piles, indicating the eompositive coefficient is a variable and can hardly be used to determine the pile shaft compression. Thirdly, Boltzrnann model can be used to study the pile shaft compression subjected to pile peak load, with the eorrelativity coefficient being over 0.996. The eompositive eorrelativity coefficient of 5 piles is 0.9871. Therefore, the pile shaft compression of steel pipe piles can be predicted by existing regression curves and associated equations. Fourthly, Boltzmann mathematic model is appropriate to be used in this study, and it can provide new method for the estimation of pile shaft compression and the determination of ultimate bearing capacity of piles. Finally, ultimate bearing capacity of piles is in negative linear relation with length-diameter ratio.

关 键 词：数学描述 Boltzmann模型 桩顶荷载-桩顶沉降曲线 桩身压缩-桩顶荷载曲线 综合系数 管桩 

分 类 号：TU473.13[建筑科学—结构工程] TU375.1[建筑科学—土工工程]