高灵敏度淤泥质土“预制方桩-旋喷桩”风机基础施工顺序影响  

Influence of Construction Sequence on"Precast Square Pile-Jet Grouting Pile"Fan Foundation in High Sensitivity Mucky Soil

作　　者：孙大勇 周全林 肖飞 Sun Dayong;Zhou Quanlin;Xiao Fei(East China Xinhua Energy Investment Co.,Ltd.,Yangzhou 225000,China)

机构地区：[1]华东新华能源投资有限公司,扬州225000

出　　处：《特种结构》2023年第4期103-107,共5页Special Structures

摘　　要：“预制方桩-旋喷桩”组合基础形式适用于高灵敏度淤泥质土,但预制方桩沉桩过程中产生的挤土效应可能对旋喷桩造成影响,且预制方桩与旋喷桩的施工顺序也可能影响预制方桩的水平承载力。依托江苏连云港某风电场工程开展现场试验研究“预制方桩-旋喷桩”风机基础,分析预制方桩与旋喷桩施工顺序对预制方桩承载力和水平位移的影响,以及预制方桩挤土效应对旋喷桩位移的影响。结果表明,旋喷桩可提高预制方桩单桩水平极限承载力并减小水平位移量,但先进行旋喷桩施工后进行预制方桩沉桩将大大延长基础工程施工工期。预制方桩在沉桩过程中存在挤土效应,使旋喷桩产生明显的侧向位移。建议实际工程中先进行预制方桩沉桩施工,后进行旋喷桩地基加固,既不影响工程周期,又可减小预制方桩挤土效应对旋喷桩的影响。Composite foundation with precast square pile and rotary jet grouting pile is suitable for high sensitivity mucky soil,but the squeezing effect of precast square pile in the process of sinking pile may affect the rotary jet grouting pile,and the construction sequence of precast square pile and rotary jet grouting pile may also affect the horizontal bearing capacity of precast square pile.Based on a wind farm project in Lianyungang,Jiangsu Province,a field test was carried out to study on the fan foundation of"precast square pile-jet grouting pile".The influence of construction sequence of precast square pile and jet grouting pile on the bearing capacity and horizontal displacement of precast square pile,as well as the influence of soil extrusion effect of precast square pile on the displacement of jet grouting pile was analyzed.The results show that the rotary jet grouting pile can improve the horizontal ultimate bearing capacity and reduce the horizontal displacement of the precast square pile,but the construction period of the foundation project will be extended significantly if the rotary jet grouting pile is constructed before sinking the precast square pile.In the process of pile sinking,the precast square piles performance obvious lateral displacement due to the soil squeezing effect.It is suggested that the precast square pile should be driven first and then the rotary jet grouting pile should be used to strengthen the foundation,which not only does not affect the engineering period,but also reduces the squeezing effect of the precast square pile on the rotary jet grouting pile.

关 键 词：预制方桩 旋喷桩 地基处理 施工顺序 水平承载力 

分 类 号：TM614[电气工程—电力系统及自动化] TU753[建筑科学—建筑技术科学]