不考虑桩端承力的锚桩法新工艺试验研究  

Experimental Research on New Technology of Anchor Pile Method Without Considering Pile End Bearing Capacity

作　　者：陈雪峰 王京杭 孙立山[2] 赵标[1] CHEN Xuefeng;WANG Jinghang;SUN Lishan;ZHAO Biao(China Railway Bridge&Tunnel Technologies Co.Ltd.,Nanjing 210061,China;China Railway Major Bridge Reconnasissance&Design Institude Co.Ltd.,Wuhan 430050,China)

机构地区：[1]中铁桥隧技术有限公司,南京210061 [2]中铁大桥勘测设计院集团有限公司,武汉430050

出　　处：《铁道建筑》2022年第11期85-89,共5页Railway Engineering

摘　　要：在公铁两用桥梁的基桩静载试验中,为了增加传统加载方法的应用范围,提高其对大吨位基桩的适用性,以宜宾市临港大桥锚桩法试桩为背景,通过优化桩底空间结构,设置钢垫板与可发性聚苯乙烯泡沫板(Expanded Polystyrene,EPS板),并且利用EPS板的减荷属性,提出不考虑端承型桩的桩端承力转而测试桩侧摩阻力的新工艺。采用FLAC3D软件对试桩进行数值模拟,并与试验数据进行对比。结果表明:位移实测值与数值模拟值变化规律基本一致,没有发生突变现象;EPS板顶板中心点在加载到最后一级时最大位移很小,绝大部分竖向试验荷载通过桩侧摩阻力以剪应力的形式传递到桩周土体中,只有少部分竖向试验荷载传递到EPS板上,因而产生的压缩变形很小,远小于极限压缩量,与桩端承力真实值相比,可以忽略不计。新工艺不仅减少了试验加载吨位,还提高了试桩工程的成功率与桩侧摩阻力测试的准确性,为设计单位优化桩长提供真实有效的试验数据。In the static load test of foundation piles for rail-cum-road bridge,in order to increase the application range of traditional loading methods and improve their applicability to large tonnage foundation piles,taking the anchor pile test method of Yibin Lingang Bridge as the background,through optimizing the spatial structure of pile bottom,setting steel backing plates and expanded polystyrene(EPS)plates,and using the load reduction properties of EPS plates,a new technology of testing pile side friction instead of considering the pile end bearing capacity of end bearing piles was proposed. FLAC3D software was used to simulate the test pile and compare with the test data. The results show that the measured displacement values are basically consistent with the numerical simulation values,and there is no sudden change. The maximum displacement of the center point of the top plate of the EPS plate is very small when it is loaded to the last level. Most of the vertical test loads are transferred to the soil around the pile in the form of shear stress through the pile side friction,and only a few of the vertical test loads are transferred to the EPS plate. Therefore,the resulting compression deformation is very small,far less than the ultimate compression,and can be ignored compared with the true value of the pile end bearing force. The new technology not only reduces the test loading tonnage,but also improves the success rate of the pile test project and the accuracy of the pile side friction test,providing real and effective test data for the design unit to optimize the pile length.

关 键 词：公铁两用桥梁 锚桩法新工艺 试验研究 FLAC3D软件 EPS板 基桩静载试验 

分 类 号：U448.121[建筑科学—桥梁与隧道工程] U443.15[交通运输工程—道路与铁道工程]