Analysis of installation forces for helical piles in clay | NOVA. The University of Newcastle's Digital Repository
Analysis of installation forces for helical piles in clay | NOVA. The University of Newcastle's Digital Repository
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粘土中螺旋桩安装力分析|
DOI：
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
K. Todeshkejoei
中科院分区：
文献类型：
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作者：
J. Hambleton;S. Stanier;C. Gaudin;K. Todeshkejoei
安装力在螺旋桩的设计和性能中起着核心作用，特别是因为安装扭矩经常被用作桩的极限承载力的指标。本文建立了粘土中单螺旋桩安装力矩的分析模型。作为作者最近研究的延伸，所提出的模型不仅考虑了发生在螺旋板上的力，而且考虑了沿轴产生的剪切应力，这两者都影响安装力。该模型给出了一个直接的表达式，将安装扭矩与土壤的不排水抗剪强度、埋置深度、螺旋直径和螺距、轴直径、人群（轴向）力以及沿轴的粘附系数联系起来。通过敏感性分析评估这些因素对安装扭矩的影响，以及用于从安装中推断容量的“容量-扭矩比”。通过与经验容量-扭矩比的比较，提供了一定程度的验证，敏感性分析揭示了经验模型中被忽视但仍有重大影响的因素。
ABSTRACT Installation forces play a central role in the design and performance of helical piles, especially since the installation torque is often used as an indicator of the pile’s ultimate capacity. This paper presents an analytical model for predicting the installation torque for single-helix piles in clay. As an extension of a recent study by the authors, the proposedmodel considers not only the forces occurring on the helical plates but also the shear stresses generated along the shaft, both of which impact the installation forces. The model yields a straightforward expression that relates installation torque to the undrained shear strength of the soil, embedment depth, helix diameter and pitch, shaft diameter, crowd (axial) force, and adhesion coefficient along the shaft. The influence of these factors on the installation torque, as well as the “capacity-to-torque ratio” used to infer capacity from the installation, is assessed through a sensitivity analysis. Some level of validation is provided through a comparison with empirical capacity-to-torque ratios, and the sensitivity analysis reveals factors that are neglected in empirical models but nevertheless have a significant influence.