基于Copula函数的CFG桩复合地基载荷—变形曲线的概率分析

发布时间：2018-05-13 13:23

本文选题：复合地基 + CFG桩　；参考：《岩土力学》2016年S1期

【摘要】：CFG桩(cement-fly ash-gravel pile)复合地基是一种重要的地基处理形式,在日益增加的大面积住宅和商业开发中作用越来越突出,然而该种桩型的加卸荷-沉降变形特性仍然需深入研究,尤其在概率评估方面。根据北京星光影视股份有限公司生产科研基地项目工地中的21根CFG桩单桩静载试验和32个复合地基静载试验的原位加卸载测试成果,采用两参数的双曲线或幂曲线回归拟合了每一条加荷-变形曲线。由于土体的内在各向异性和其强度的变异性,评估整个场地的加荷-变形曲线时,其回归参数表现出了较大的离散性。将一个场地的多组回归参数组成一个随机向量,其加载-位移曲线的不确定性可由简单的两变量随机向量体现,引入双变量联结函数(Copula)描述随机回归参数间的相依性。最后,考虑正常使用极限状态,采用基于Copula函数的模拟模型计算了CFG桩复合地基的可靠度指标。研究结果有助于改进CFG桩复合地基的概率设计与评估。
[Abstract]:CFG pile cement-fly ash-gravel pile) composite foundation is an important foundation treatment form, which plays a more and more important role in the increasing area of residential and commercial development. However, the characteristics of unloading and settlement deformation of this type of pile still need to be deeply studied. Especially in probability evaluation. According to the results of in-situ loading and unloading tests of 21 CFG piles single pile and 32 composite foundation static load tests in the project site of Beijing Xingguang Film & Television Co., Ltd. The hyperbolic curve or power curve with two parameters is used to fit each load-deformation curve. Because of the intrinsic anisotropy and the variability of the strength of the soil, the regression parameters of the soil show a greater dispersion when evaluating the load-deformation curve of the whole site. The uncertainty of load-displacement curve can be represented by a simple two-variable random vector, and the bivariate coupling function is introduced to describe the dependence of random regression parameters. Finally, the reliability index of CFG pile composite foundation is calculated by using the simulation model based on Copula function. The results are helpful to improve the probability design and evaluation of CFG pile composite foundation.
【作者单位】：北京市建筑工程研究院;北京市建设工程质量第一检测所有限责任公司;北京科技大学数理学院;
【分类号】：TU473.1

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