【作者】 李坛；

【导师】 赵其华；

【作者基本信息】 成都理工大学 ， 防灾减灾工程及防护工程， 2008， 硕士

【摘要】 CFG桩复合地基自从1988年立项研究以来,由于该项技术在施工工艺上具有施工速度快、工期短、质量容易控制、工程造价低等特点,经过二十年的工程实践已经获得工程界的一致认可,并被广泛的应用于地基处理。本文结合南充市川北医学院住院楼的CFG桩复合地基处理工程,利用数值模拟和多元统计的方法对夯扩CFG的受力特性进行了探讨和研究。分析采用的方法是先对实验数据进行分析,然后在此基础上建立施工场地的三维数值模型,利用数值分析的方法分析各种因数对夯扩CFG桩受力特性的影响,之后再以数值分析的数据采用超趋势面的分析方法研究多个因素同时变化对夯扩CFG桩承载特性的影响。首先,通过现场实验数据对夯扩CFG复合地基桩的轴力传递和桩土荷载分担比进行了分析,选取了短期观测实验的五根桩进行分析,通过对桩土荷载分担比的线形拟合发现,除其中一根桩由于初始桩土荷载分担比相差较大外,其它几根桩拟合程度都很好,表明其线形特征比较明显,可以用直线拟合,并且其斜率与其所处位置关系不大。其次,运用数值模拟的方法对施工现场实验进行模拟,通过改变各影响参数分析其对桩体轴力,桩土荷载分担和负摩擦阻力的影响。分析发现桩身轴力最大值基本上与桩半径的增加成线形关系,但是由于地层不同,不同部位的桩的线形关系并不一样,其斜率并不相等。最后利用多元统计中的超趋势面分析原理,对单因素的数值模拟结果进行拟合超趋势面,然后对多因素同时影响的CFG桩的受力特性进行分析,直观的观察到不同因素之间是如何相互作用的。分析表明桩长及桩半径对桩的轴力影响较大,褥垫层厚度较大时对桩的轴力影响较小,桩身刚度对桩轴力的影响较小,调整桩长和桩径可以取得桩体轴力的最小值。更多还原

【Abstract】 The time of the CFG pile composite foundation research is about 20 year, since the first research to it in 1988.In these years,because this technology has the quickly construction speed, the time of construction is short, the quality easy to control and the building cost of projects is low, it has received the engineering’s high praise and was widely used in foundation treatment.This article analysised and discussed the force characteristic of it base on the the CFG pile compound ground treatment project of Nanchong Northern Sichuan Province Medical School hospital buiding. The analysis method used by this article is experiment data analysis at the first step. Then creat three-dimensional model based on the first step to analyse the rammed expanded CFG pile. Afterward uses the hyper-trend surface by numerical simulation’s data the analysis method to study the influence which caused by many factors simultaneously change to the rammed expanded CFG pile.First, it was studied that the axial force transmission and the load shares ratio of pile and soil by the experiment data analysis. And it was Selected the short-term observation experiment’s five piles to carry on the analysis. Through compare the load shares ratio curve of pile and soil to straight line found that except one pile having big error at Initial time all pile’s load shares ratio curve are similar to straight line. It indicated that its linear characteristic is quite obvious and could use the straight line to replaces the cuve and the slope ratio of it is irrelevant with its position.Secondly, execute simulation using numerical simulation’s method to simulate the construct-location experiment. By the way to changes each influence parametric analysis its influence to the pile axial force, the load shares ratio of pile and soil and negative friction force. Through the analysis found that the pile a axial force maximum value basically increases at the linear relations with the pile radius, but because the stratum is different, at different positon pile’s linear relations are dissimilar and its slope ratio is not equal.Finally, useing multi-dimensional statistics’ hyper-trend surface analysis principle,created a hyper-trend surface with the single factor’s numerical simulation result. Then analised the CFG pile’s force characteristic at the multi-factors affects, to observe the interaction of different factors. The analysis indicated that the pile length and the pile radius are big influence factors to the pile axial force. When mattress thickness is big it has small infuence to the pile axial force. The pile rigidity has small inflence to the pile axial force. by adjustment the pile length and the pile diameter may obtain the the minimum value of the pile axial force.更多还原