基于双荷载箱自平衡法的黄土地区桩基承载特性试验研究  

Experimental study on load bearing characteristics of pile foundation in loess area based on double load cell self-balanced method

作　　者：王锦涛 魏进[1] 卞海丁 WANG Jintao;WEI Jin;BIAN Haiding(School of Highway,Chang’an University,Xi’an 710064,China)

机构地区：[1]长安大学公路学院,西安710064

出　　处：《中国科技论文》2024年第7期777-784,共8页China Sciencepaper

基　　金：陕西省交通运输厅交通科研项目(22-24K);陕西省住房城乡建设科技科研开发计划项目(2022-K53);中央高校基本科研业务费专项资金资助项目(310821173701)。

摘　　要：为探究双荷载箱自平衡法在黄土地区的适用性,以陕西地区某城市立交工程2根抗压试桩为研究对象,对桩基竖向承载力进行检测,分析了桩底压浆前、后桩基承载力的提升程度及组成差异,并从桩身轴力、桩侧摩阻力及桩端阻力3个方面对荷载传递规律进行研究。结果表明:压浆后桩基极限承载力相较于压浆前提升了51.74%,其中桩端阻力值增加到压浆前的2.5倍,且占桩基承载力的比重明显增大;双荷载箱自平衡试验中,桩身轴力在上荷载箱处产生并达到最大值,向桩顶和桩底逐渐衰减,轴力向下衰减速率明显更快;桩侧摩阻力由上荷载箱处开始发挥,沿桩身传递过程中,由于桩土相对位移逐渐减小,最终衰减至最小值;下部桩身桩端反力-位移曲线与传统静载试验的荷载-位移曲线类似,但两者桩周土应力场存在差异。In order to explore the feasibility of the double load cell self-balanced method in loess areas,two compressive test piles of an urban overpass project in Shaanxi province were taken as the research objects and the vertical bearing capacity of pile foundation was tested.Additionally,the difference of the lifting degree and composition of the bearing capacity of pile foundation before and after pile bottom grouting was analyzed.Furthermore,the load transfer law was studied in terms of pile axial force,pile side friction resistance and pile end resistance.The results show that the ultimate bearing capacity of pile foundation after grouting is increased by 51.74%compared with that before grouting,and the resistance value of pile end is increased by 2.5 times before grouting,and its proportion in the bearing capacity of pile foundation is increased obviously.In the double load cell self-balanced test,the axial force of the pile body is generated and reaches its maximum value at the upper load cell,and gradually decays towards the top and bottom of the pile.The lateral friction of pile is found to start from the upper load cell and decreases to the minimum value in the process of transmission along the pile body due to the gradual decrease of the relative displacement of pile and soil.The reaction and displace⁃ment curve of the pile end is similar to the load displacement curve of the traditional static load test,while the differences lie in the soil stress field around the pile.

关 键 词：桥梁工程 自平衡法 双荷载箱 桩底压浆 桩基极限承载力 荷载传递规律 

分 类 号：TU473.11[建筑科学—结构工程]