基于土体三相性计算单桩竖向承载力的理论分析  

Theoretical Analysis on Calculating Vertical Bearing Capacity of Single Pile Base on Tri-phase of Soil

作　　者：乐琪浪[1] 叶赞[2] 林承灏[3] 

机构地区：[1]中国地质调查局水文地质环境地质调查中心,河北保定071051 [2]淮南矿业集团潘北矿,安徽淮南232001 [3]安徽理工大学地球与环境学院,安徽淮南232001

出　　处：《路基工程》2011年第3期159-161,165,共4页Subgrade Engineering

摘　　要：建筑桩基技术规范公式得出的单桩竖向承载力在部分工程中与实际偏差较大。桩侧摩擦力公式中土层厚度li直接取单层土层的厚度,而未考虑土层的三相性,实际对桩提供有效摩擦阻力的只是土颗粒的作用,规范以整体提供摩擦阻力的计算法存在缺陷。基于土体三相性考虑,建立桩侧与土的物理力学模型计算单桩竖向承载力,分析得出计算式。通过工程试验与分析结果认为:桩侧有效摩擦厚度与土层的厚度以孔隙比建立其关系,桩侧摩阻力与土层孔隙比的大小成反比,计算结果与实际值吻合较好。Vertical bearing capacity values of single pile obtained from the formula specified in technical specification for building pile foundation is very different from the actual values in some engineering projects.In the formula of pile shaft friction,soil thickness li is just the single layer thickness without considering the tri-phase of soil.Through analyzing the component of soil,only soil particles provide effective friction to the pile,but the formula considers all the soil provide friction to the pile,which is the defect of the specification.Considering tri-phase of soil,this paper establishes the physical model of pile shaft and soil to calculate the vertical bearing capacity of single pile and get the new formula through analysis.Through engineering test and analysis results,it is considered that the effective friction thickness of pile shaft has a relationship with the void ratio of soil.The shaft resistance is inversely proportional to the void ratio.The values show a good agreement with the actual values.

关 键 词：土体三相性 物理模型 单桩竖向承载力 桩侧阻力 

分 类 号：TU473.12[建筑科学—结构工程]