浅析CFG桩复合地基设计计算

简述CFG桩复合地基的基本概念,分析CFG桩复合地基承载力计算和CFG桩复合地基变形计算,以及单桩竖向承载力特征值的取值要求和褥垫层厚度确定。     

石粉CFG桩在路基工程中应用分析

文章分析石粉CFG桩在公路中应用,阐述了石粉CFG桩复合地基设计,介绍石粉CFG桩设计长度、桩径、桩间距、桩身强度、桩身材料、褥垫层及布桩形式、单桩及复合地基承载力,通过施工及质量检测达到了设计标准,为石粉CFG桩施工提供一定参考。     

CFG桩复合地基承载特性分析

CFG桩复合地基具有变形模量高、承载力提高幅度大等特点，设计时可以通过改变桩体材料配比，改变桩体直径、桩长、桩距、垫层厚度等设计参数，使承载力提高以达到设计要求。其中，褥垫层有协调桩和桩间土变形的能力，使得桩和桩间土始终参与工作，一般工程中取10～30cm较为合理。     

褥垫层在CFG桩中的作用研究

褥垫层是CFG桩复合地基的重要组成部分。从承受荷载、应力传递和复合地基性状3个方面对褥垫层的作用机理作了详细阐述。     

CFG桩复合地基中褥垫层的抗震性能分析

水平地震时,用水平剪力代替上部结构的地震作用后,利用剪力层法求解出了褥垫层的运动微分方程,从而可反演出褥垫层内的水平动剪力传递过程.由实例分析可知放置适当厚度的褥垫层,可减少了上部结构的水平地震作用;褥垫层的存在,在一定程度上提高了整个CFG桩复合地基的抗震性能.     

CFG桩复合地基中褥垫层的抗震性能分析

水平地震时，用水平剪力代替上部结构的地震作用后，利用剪力层法求解出了褥垫层的运动微分方程，从而可反演出褥垫层内的水平动剪力传递过程。由实例分析可知：放置适当厚度的褥垫层，可减少了上部结构的水平地震作用；褥垫层的存在，在一定程度上提高了整个CFG桩复合地基的抗震性能。     

水泥粉煤灰碎石桩在地基加固中的应用

水泥粉煤灰碎石桩是由水泥、粉煤灰、石屑或砂加水拌和而形成的高粘结强度桩(简称CFG桩),桩、桩间土和褥垫层一起构成复合地基。与其它桩基相比,该技术具有施工速度快、工期短、质量容易控制、工程造价低廉等特点。实践证明,采用CFG桩可大幅度提高地基承载力,减少地基变形,同时还取得了较高的经济和社会效益。本文主要从方案选定、施工过程、效果评价等方面出发来阐述该技术具有的优势和特点。     

CFG桩在地基处理工程中的应用

1 原理及适用范围 CFG桩是水泥粉煤灰碎石桩的简称(即cement fIying-ash gravel pile),它是由水泥、粉煤灰、碎石、石屑或砂加水拌和形成的高粘结强度桩,CFG桩和桩间土、褥垫层一起形成复合地基(见图1). CFG桩是针对碎石桩承载特性的一些不足加以改进发展起来的,它改善了碎石桩的刚性,使其不仅能很好地发挥全桩的侧阻作用,同时也能很好地发挥其端阻作用.     

复合地基加固处理在某高层建筑中的应用

本文介绍了CFG桩的特点及在地基处理中的作用、CFG桩加固地基的机理和CFG桩复合地基承载力计算方法.从CFG桩加固地基的效果看,CFG桩在高层建筑结构中的应用具有良好的综合效益,具有广阔的应用前景.     

CFG桩复合地基承载力试验研究

通过对新株洲站CFG桩的试验研究和静载检测及数据分析,介绍CFG桩复合地基承载力的静载试验检测方法;证明静载试验能够检测CFG桩复合地基的承载力.试验结果为完善CFG桩复合地基加固软土地基检测标准提供依据,为在高速铁路软土地基加固工程中推广应用提供指导.     

关于核心筒基础筏板褥垫层施工的探讨

应用计算机技术分析、解决大坡度褥垫层现场施工问题,保证CFG桩复合地基承栽模式,为同种结构的CFG复合地基中带坡度褥垫层的施工提供经验借鉴．根据具体工程实例,运用AutoCAD和Excel计算机技术对核心筒结构筏板基础处的施工方法进行详细地分析和论证．     

临近既有线施工路基CFG桩工艺研究

新建长吉城际铁路并行既有长图线,路基地基处理设计为CFG桩,施工工点地势低洼,地下水位高,表土承载力低。为保证施工安全和既有线路基稳定,优化CFG桩施工工艺、采取相应施工方法及监测手段,保证圆满完成施工任务。     

堆载作用对邻近CFG桩复合地基影响的数值模拟研究

通过有限元分析软件ANSYS11.0,对邻近地面堆载作用下已承载CFG桩复合地基的力学性状进行了分析,对已承载CFG桩复合地基中桩体在不同的地面堆载荷载、堆载作用位置、承台受荷状态以及土体压缩模量等工况中的性状进行了研究,进而分析得出堆载的作用位置、大小以及复合地基所在场地范围内土体压缩模量是几个比较重要的影响因素,对临近堆载的CFG桩复合地基的力学性状影响较大。     

Bearing Capacity of Mixed Pile with Stiffness Core

To study load transfer mechanism and bearing capacity of a mixed pile with stiffness core (MPSC), which is formed by inserting a precast reinforced concrete pile (PRCP), in-situ tests involving MPSCs with different lengths, diameters, water cement ratios and PRCPs, cement mixed piles, and drilling hole piles, were carried out. Limit bearing capacities, load-settlement curves and stress distribution of MPSCs and mixed piles were obtained. The load transfer between cement soil and PRCP was analyzed by finite element method (FEM). Test results and FEM analysis show that an MPSC has fully utilized the big friction from a cement mixed pile and the high compressive strength from a PRCP which transfers outer top load into the inner cement soil, and that inserting a PRCP into a mixed pile changes the stress distribution of a mixed pile and improves frictional resistance between a mixed pile and soil. The length and the section area on PRCP of an MPSC both have an optimum value. Adopting MPSC is effective in improving the bearing capacity of soft soil ground.     

CFG桩处理软土地基的应用与分析

用CFG桩处理软土地基,检测结果表明,在合理设计的前提下,严格工艺管理和质量管理,利用CFG桩加固地基是可行的。     

后压浆技术在PHC管桩工程中的应用

从后压浆技术的概念提出及其机理分析入手。结合实际桩基工程中后压浆技术的应用与现场检测。探讨后压浆技术在PHC管桩工程事故处理和加固等方面的机理作用及效果。通过注浆前后试验结果对比。阐明后压浆技术能提高持力层地基承载力及桩侧摩阻力，改善桩身质量和桩的荷载传递性能。使桩基综合承载力大幅度提高，并缩短工期。     

粉喷桩复合地基在河漫滩相软土地基处理中的应用

结合某市健康园三期工程18#楼软土地基处理工程实例,研究了粉喷桩复合地基处理河漫滩相软土的加固机理和常见检测方法,分析了粉喷桩复合地基设计与施工中常见问题及其解决措施。实际加固效果检测资料表明,18#楼地基经处理后其承载力有了明显的提高,加固效果明显。     

Bearing capacity and load transfer mechanism of a static drill rooted nodular pile in soft soil areas

The static drill rooted nodular pile is a new type of pile foundation consisting of precast nodular pile and the surrounding cemented soil. This composite pile has a relatively high bearing capacity and the mud pollution will be largely reduced during the construction process by using this type of pile. In order to investigate the bearing capacity and load transfer mechanism of this pile, a group of experiments were conducted to provide a comparison between this new pile and the bored pile. The axial force ofa precast nodular pile was also measured by the strain gauges installed on the pile to analyze the distribution of the axial force of the nodular pile and the skin friction supported by the surrounding soil, then 3D models were built by using the ABAQUS finite element program to investigate the load transfer mechanism of this composite pile in detail. By combining the results of field tests and the finite element method, the outcome showed that the bearing capacity of a static drill rooted nodular pile is higher than the bored pile, and that this composite pile will form a double stress dispersion system which will not only confirm the strength of the pile, but also make the skin friction to be fully mobilized. The settlement of this composite pile is mainly controlled by the precast nodular pile; meanwhile, the nodular pile and the surrounding cemented soil can be considered as deformation compatibility during the loading process. The nodes on the nodular pile play an important role during the load transfer process, the shear strength of the interface between the cemented soil and the soil of the static drill rooted pile is larger than that of the bored pile.