砂土地基中钻进比对螺旋桩安装性能和抗拔承载性能的影响  

Installation and pull-out performance of helical pile embedded in sand influenced by advancing ratio

作　　者：颜然 孔纲强[1,2] 于江华 YAN Ran;KONG Gang-qiang;YU Jiang-hua(College of Civil and Transportation Engineering,Hohai University,Nanjing,Jiangsu 210024,China;Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering,Hohai University,Nanjing,Jiangsu 210024,China)

机构地区：[1]河海大学土木与交通学院,江苏南京210024 [2]河海大学岩土力学与堤坝工程教育部重点实验室,江苏南京210024

出　　处：《岩土力学》2024年第6期1778-1788,共11页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.522034711)。

摘　　要：螺旋桩在输电线路杆塔和光伏支架等工程基础中获得了推广应用,然而沉桩速率对螺旋桩沉桩效应和承载力特性的影响机制尚不明确。通过开展砂土地基中螺旋桩沉桩与抗拔承载性能模型试验,分析了螺旋桩钻进比与扭矩、下压力之间的关系,建立了考虑承载力-扭矩-下压力相互影响的极限抗拔承载性能相关系数K'_(t)的计算方法。与既有文献试验结果及理论计算方法进行了对比分析,验证了所建立的计算方法的可靠性。研究结果表明:钻进比与螺旋桩的沉桩扭矩和下压力呈线性关系,钻进比对沉桩扭矩的影响幅度大于下压力;降低沉桩过程中钻进比可有效提高螺旋桩的抗拔承载力,钻进比为0.6工况下的抗拔极限承载力可达到钻进比为2工况下的2.9倍;所建立的砂土地基螺旋桩抗拔极限承载力-扭矩-下压力相关系数计算方法,计算误差小于30%,具有较好的准确性和适用性。Helical piles have gained widespread application in engineering foundations such as transmission lines and photovoltaic supports.However,the mechanism by which the installation rate affects the installation effect and bearing capacity characteristics of helical piles remains unclear.This study conducted model tests on the installation and uplift resistance of helical piles in sandy soil foundations.The relationships between the advancing ratio and torque,downward pressure of the helical piles were analyzed.A modified calculation method for the correlation coefficient K'_(t) of ultimate bearing capacity-torque-downforce was established.The reliability of the modified calculation method was verified through comparative analysis with experimental results from the literature and other calculation methods.The findings indicate that the advancing ratio has a linear relationship with both the installation torque and downward pressure of the helical piles,with a greater impact on the installation torque.Reducing the advancing ratio during the installation process can effectively enhance the uplift bearing capacity of the helical piles.Under the experimental conditions,the ultimate uplift capacity at an advancing ratio of 0.6 can reach 2.9 times that at an advancing ratio of 2.The proposed calculation method for the ultimate bearing capacity-torque-downforce correlation coefficient in sandy soil foundations exhibits an overall calculation error of less than 30%,demonstrating good accuracy and applicability.

关 键 词：螺旋桩 沉桩扭矩 下压力 钻进比 抗拔极限承载力 

分 类 号：TU473[建筑科学—结构工程]