偏心荷载作用下CFG桩复合地基基底反力试验研究及多桩型复合地基设计计算
发布时间：2018-09-07 14:31
【摘要】：CFG桩复合地基技术通过二十余年的科研和工程实践,从最初应用于多层建筑发展到广泛应用于高层和超高层建筑地基处理,取得了显著的经济效益和社会效益。本文主要完成以下工作： 1.完成模拟高低层连体建筑形成偏心荷载作用的室内模型试验,获得轴心荷载作用下天然地基、均匀布桩CFG桩复合地基基底反力可简化为均匀分布；偏心荷载作用下天然地基、均匀布桩CFG桩复合地基基底反力可简化为线性分布；偏心荷载作用下高层部位均匀布置长桩、低层部位均匀布置短桩的局部均匀布桩CFG桩复合地基基底反力可简化为局部均匀分布；“等变形”条件下(本文根据试验条件,当基础长度方向两端差异沉降小于某一较小数值时,即认为左右两端为变形相等的“等变形”状态)高层部位均匀布置长桩、低层部位均匀布置短桩的局部均匀布桩CFG桩复合地基,基底反力可简化为长桩区域高、短桩区域低的局部均匀分布,且按高层、低层部位复合地基的复合模量进行分配。 2.基于以集中力表示的静力平衡方程,推导了多桩型复合地基承载力表达式；指出多桩型复合地基施工完成后的桩间土承载力提高系数,与土性、施工工艺和桩间距有密切的关系；提出不同布桩形式下,多桩型复合地基面积置换率的计算方法；提出多桩型复合地基计算变形时如何进行分区,各分区复合模量提高系数如何计算,以及如何进行分层,各分层复合模量如何进行计算,并给出多桩型复合地基变形计算的步骤；提出不同布桩形式下,多桩型复合地基的质量检测方法。 3.针对目前天然地基、CFG桩复合地基变形计算中,存在压缩模量取值不当的问题,提出对固结试验结果进行拟合分析。在综合分析大量前人研究拟合固结试验结果成果的基础上,提出新的数学模型：e=c[exp(aNpbN)-1]+e0 该数学模型除具有单调递减和呈“S”形的特点外,还满足边界条件：当压力p=0时,孔隙比e=e0,为天然孔隙比；当压力p→+∞时,孔隙比e=e0,为压密极限。本文运用最优化方法求得的各参数,具有唯一的确定值,并运用VC++编制了相关可视化程序。对大量固结试验结果的拟合分析表明,本文提出的数学模型对固结试验结果的拟合程度高,因而可直接运用本文提出的数学模型对固结试验结果进行拟合,可通过编制相关程序确定自重压力至自重压力与附加压力之和的压力段的压缩模量,实现人机对话,避免人为误差,达到提高变形计算精度的目的。
[Abstract]:Through more than 20 years of scientific research and engineering practice, the CFG pile composite foundation technology has been developed from the initial application in multi-storey buildings to the extensive application in the foundation treatment of high-rise and super-high-rise buildings, and has achieved remarkable economic and social benefits. The main work of this paper is as follows: 1. The indoor model test is completed to simulate the eccentric load action of high and low story contiguous building. The natural foundation under axial load is obtained. The reaction force of CFG pile composite foundation can be simplified to uniform distribution, and the natural foundation under eccentric load, The reaction force of CFG pile composite foundation can be reduced to linear distribution. Under the condition of "equal deformation", the reaction force of the CFG pile composite foundation can be simplified as the local uniform distribution under the condition of "equal deformation". When the differential settlement in the direction of foundation length is less than a certain value, that is, it is considered that the two ends of the foundation are equal in deformation "equal deformation") the long piles are uniformly arranged in the upper part of the foundation. The local uniformly distributed pile CFG pile composite foundation with short pile is arranged uniformly in the lower layer. The reaction force of the base can be simplified as the local uniform distribution in the long pile area and the short pile area, and according to the high level, the base reaction force can be reduced to the local uniform distribution in the long pile area and the short pile area. Distribution of composite modulus of composite foundation at low level. 2. Based on the static equilibrium equation expressed by concentrated force, the bearing capacity expression of multi-pile composite foundation is derived, and it is pointed out that the coefficient of soil bearing capacity between piles and soil is improved after the construction of multi-pile composite foundation. The construction technology is closely related to pile spacing, the calculation method of area replacement rate of multi-pile composite foundation under different pile layout forms is put forward, and how to partition the deformation of multi-pile composite foundation is put forward. How to calculate the increasing coefficient of composite modulus, how to delaminate, how to calculate the composite modulus of each layer, and how to calculate the deformation of multi-pile composite foundation are given. Quality testing method of multi-pile composite foundation. 3. In view of the problem of improper compression modulus in the deformation calculation of natural foundation with CFG pile composite foundation at present, the fitting analysis of consolidation test results is put forward. On the basis of synthetically analyzing the results of a large number of previous studies and fitting consolidation tests, a new mathematical model, exp (aNpbN) c [exp (aNpbN) 1] e 0, is proposed, which has the characteristics of monotone decline and "S" shape. It also satisfies the boundary conditions: when the pressure p = 0, the porosity ratio e0 is the natural porosity ratio, and when the pressure p 鈭，
本文编号：2228535
[Abstract]:Through more than 20 years of scientific research and engineering practice, the CFG pile composite foundation technology has been developed from the initial application in multi-storey buildings to the extensive application in the foundation treatment of high-rise and super-high-rise buildings, and has achieved remarkable economic and social benefits. The main work of this paper is as follows: 1. The indoor model test is completed to simulate the eccentric load action of high and low story contiguous building. The natural foundation under axial load is obtained. The reaction force of CFG pile composite foundation can be simplified to uniform distribution, and the natural foundation under eccentric load, The reaction force of CFG pile composite foundation can be reduced to linear distribution. Under the condition of "equal deformation", the reaction force of the CFG pile composite foundation can be simplified as the local uniform distribution under the condition of "equal deformation". When the differential settlement in the direction of foundation length is less than a certain value, that is, it is considered that the two ends of the foundation are equal in deformation "equal deformation") the long piles are uniformly arranged in the upper part of the foundation. The local uniformly distributed pile CFG pile composite foundation with short pile is arranged uniformly in the lower layer. The reaction force of the base can be simplified as the local uniform distribution in the long pile area and the short pile area, and according to the high level, the base reaction force can be reduced to the local uniform distribution in the long pile area and the short pile area. Distribution of composite modulus of composite foundation at low level. 2. Based on the static equilibrium equation expressed by concentrated force, the bearing capacity expression of multi-pile composite foundation is derived, and it is pointed out that the coefficient of soil bearing capacity between piles and soil is improved after the construction of multi-pile composite foundation. The construction technology is closely related to pile spacing, the calculation method of area replacement rate of multi-pile composite foundation under different pile layout forms is put forward, and how to partition the deformation of multi-pile composite foundation is put forward. How to calculate the increasing coefficient of composite modulus, how to delaminate, how to calculate the composite modulus of each layer, and how to calculate the deformation of multi-pile composite foundation are given. Quality testing method of multi-pile composite foundation. 3. In view of the problem of improper compression modulus in the deformation calculation of natural foundation with CFG pile composite foundation at present, the fitting analysis of consolidation test results is put forward. On the basis of synthetically analyzing the results of a large number of previous studies and fitting consolidation tests, a new mathematical model, exp (aNpbN) c [exp (aNpbN) 1] e 0, is proposed, which has the characteristics of monotone decline and "S" shape. It also satisfies the boundary conditions: when the pressure p = 0, the porosity ratio e0 is the natural porosity ratio, and when the pressure p 鈭，
本文编号：2228535
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