锚杆静压桩加固既有建筑基础沉降分析  

Settlement Analysis of Anchor Jacked Pile Reinforcing of the Existing Building Foundations

作　　者：宋晓光 SONG Xiaoguang(SGIDI Engineering Consulting(Group)Co.Ltd.,Shanghai 200093)

机构地区：[1]上海勘察设计研究院(集团)有限公司,上海200093

出　　处：《土工基础》2023年第2期209-212,共4页Soil Engineering and Foundation

摘　　要：将锚杆静压桩加固既有建筑产生的沉降分为附加沉降(即拖带下沉)和工后沉降,附加沉降主要由侧向挤土及桩周土强度降低引起,有限元计算成果表明,侧向挤土引起地基隆起或沉降变化与上部荷载作用和地面下15 m内地基土性质有关,土性越差,拖带沉降越大,工程案例表明,若基础下存在硬层,可能由于桩周挤土发生抬升;地基土越软弱,拖带影响范围越大,土体强度降低,受力面积减小,进而增加拖带沉降。典型建筑实测沉降数据表明,施工阶段建筑沉降量占80%,结合锚杆静压桩后成桩特点,工后沉降同样不容忽视。基于附加沉降特点,建议采用“持荷控沉-调平-封桩”方案可有效减少锚杆静压桩加固施工产生的沉降。The settlement induced by the anchor jacked pile reinforcing the existing building foundations is divided into immediate settlement and settlement after construction.The immediate settlement is induced by the lateral deformation and the strength reduction of the surrounding soft soils.Results of the finite element analysis show that the foundation heave or settlement change caused by the lateral soil squeezing is related to the upper load and the properties of foundation soil within 15m below the ground,the worse the soil property,the larger the settlement,that is,the major factor of the settlement in most of the reinforcing projects.At the same time,the project case history shows that,there is a hard soil layer under the foundation,which may be heaved due to soil squeezing around the pile.The worse the soil property is,the larger the influence range of immediate settlement is,the lower the strength of soil mass and the force bearing area are,thus increasing the settlement.According to the measured settlement data of typical buildings,the building the immediate settlement consists of 80%of the total settlement.Combined with the characteristics of the anchor jacked pile construction,the post construction settlement cannot be ignored.Based on immediate settlement characteristics,the“suspended loadingcontrollock up loading”procedure is proposed to minimize the settlements of buildings.

关 键 词：锚杆静压桩 附加沉降 持荷封桩 

分 类 号：TU433[建筑科学—岩土工程]