动刚度法在嵌岩管桩桩端加固试验中的应用研究  

Study on the Application of Dynamic Stiffness Method in Rock-embedded Pipe Pile End Reinforcement Test

作　　者：杨正龙 孙晓立 杨军 YANG Zheng-long;SUN Xiao-li;YANG Jun(Guangzhou Municipal Engineering Testing Co.,Ltd.,Guangzhou 510520;Guangzhou Institute of Building Science Group Co.,Ltd.,Guangzhou 510440)

机构地区：[1]广州市市政工程试验检测有限公司,广州510520 [2]广州市建筑科学研究院集团有限公司,广州510440

出　　处：《广州建筑》2024年第8期27-33,共7页GUANGZHOU ARCHITECTURE

基　　金：广州市建筑集团有限公司科技计划项目(2024-KJ031)。

摘　　要：采用预钻孔或中掘法施工嵌岩预应力管桩时,存在桩底沉渣难以清理的问题,过厚的孔底沉渣严重制约了桩端承载力的发挥。本文提出了采用重锤夯击加固桩底沉渣的施工方法,开展了足尺模型试验,并采用动刚度法对比分析了加固施工前后的桩基承载力变化特征。试验表明,采用重锤夯击及桩端浇筑混凝土能够确保桩端与坚硬持力层紧密连接,夯击加固后桩基动刚度提升了67%~175%。此外,现场检测方式和混凝土浇筑施工等均会影响动刚度的大小,采用动刚度法检测桩基承载力应充分考虑检测条件和施工方式对检测精度的影响。When pre-bored or center-dug method is used to construct rock-embedded prestressed pipe piles,there exists the problem that it is difficult to clean up the slag at the bottom of the pile,and the over-thickness of the slag at the bottom of the borehole seriously restricts the performance of the bearing capacity of the pile end.This paper proposes the construction method of using heavy hammer tamping to reinforce the pile bottom slag,carries out the foot-size model test,and uses the dynamic stiffness method to compare and analyze the characteristics of the change of pile bearing capacity before and after the reinforcement construction.The tests showed that the use of heavy hammer tamping and concrete pouring at the pile end could ensure that the pile end was closely connected with the hard holding layer,and the dynamic stiffness of the pile base was increased by 67%~175% after the tamping reinforcement.In addition,the on-site testing method and concrete pouring construction will affect the dynamic stiffness,and the dynamic stiffness method is used to test the bearing capacity of pile foundation with full consideration of the impact of the testing conditions and construction methods on the testing accuracy.

关 键 词：预应力管桩 嵌岩桩 沉渣层 夯击加固 动刚度 

分 类 号：TU473.16[建筑科学—结构工程]