注浆作用对输电线路挖孔桩抗拔性能影响的试验研究  

Experimental study on the effect of grouting on the uplift bearing characteristics of excavation piles in transmission line engineering

作　　者：王金锁 王宝齐 崔强 张星 杨世江 Wang Jinsuo;Wang Baoqi;Cui Qiang;Zhang Xing;Yang Shijiang(Construction Branch,State Grid Xinjiang Electric Power Co.,Ltd.,Urumqi,830063,China;State Grid Electric Power Engineering Research Institute Co.,Ltd.,Beijing 102401,China)

机构地区：[1]国网新疆电力有限公司建设分公司,乌鲁木齐830063 [2]国网电力工程研究院有限公司,北京102401

出　　处：《工程勘察》2025年第5期21-26,90,共7页Geotechnical Investigation & Surveying

基　　金：国网新疆电力公司科技项目(GCB11202100786)。

摘　　要：本文以某输电线路工程中的挖孔桩为研究对象,开展了注浆与不注浆两种设计条件、等截面与扩底两种结构型式的大直径单桩的抗拔承载性能现场足尺试验,对比分析了注浆作用对不同结构型式单桩荷载位移规律、抗拔极限承载力、桩基破坏模式、侧摩阻力的影响。结果表明:所有试验桩的荷载位移曲线整体均呈“陡降型”,注浆作用增强了桩土体系的塑性变形特征;注浆前后两种结构型式的单桩抗拔极限承载力分别提升11%、15%,相比较而言,扩底桩注浆效果更为明显;桩土体系破坏时,地表土体均出现环向和径向两类裂缝,桩周土体经历了“土体受拉破坏—局部剪切破坏—整体剪切破坏”的破坏过程,注浆作用导致地表土体破裂范围增大,对于两种结构型式的挖孔桩而言,上拔角分别提高42%、48%;基于圆柱剪切面模型,反算出的后注浆侧阻力增强系数β_(si)约为1.08,与规范推荐值上限吻合,可作为本工程后注浆挖孔桩设计与施工的参考依据。This article takes the excavation pile in a transmission line project as the study object,and conducts on-site full-scale tests on the pull-out bearing performance of large-diameter single piles with two design conditions of grouting and non-grouting,and two structural types of equal section and expanded bottom.The effects of grouting on the load displacement curve law,uplift ultimate bearing capacity,pile failure mode,and lateral friction resistance of different structural types of single piles are compared and analyzed.The results show that the load-displacement curves of all test piles exhibit a"steep-drop"shape,and the grouting effect enhances the plastic deformation characteristics of the pile-soil system;the uplift ultimate bearing capacity of single piles with two types of structures before and after grouting has been increased by 11%and 15%respectively;in comparison,the grouting effect of expanded bottom piles is more obvious;when the pile soil system is damaged,both circumferential and radial cracks appear in the surface soil,and the soil around the pile undergoes a failure process of"soil tensile failure-local shear failure-overall shear failure";the grouting effect leads to an increase in the range of surface soil fracture;for the two types of excavation piles,the uplift angle increases by 42%and 48%respectively;based on the cylindrical shear surface model,the calculated reinforcement coefficientβ_(si) of post grouting lateral resistance is approximately equal to 1.08,which is consistent with the upper limit of the recommended value in the specification.It can be used as a reference for the design and construction of post grouting digging piles in this project.

关 键 词：输电线路 挖孔桩 后注浆 现场试验 抗拔承载特性 

分 类 号：TU443[建筑科学—岩土工程]