竖向受荷螺杆桩工作性状试验研究

螺杆桩工作性状受众多因素影响,其中叶片间距和螺纹段长度是两个关键影响因素。为了研究竖向受压螺杆桩承载力及桩周土体变形渐进发展规律,进行了基于数字图像相关变形测量技术的模型试验,并利用现场实测结果初步检验了模型试验的可靠性。研究揭示了叶片间距和螺纹段长度对螺杆桩极限承载力的影响规律,建立了归一化的叶片距径比因素和螺纹段长度比因素经验表达形式,给出了本次试验条件下合理的叶片距径比和螺纹段长度比取值。研究总结了不同沉降阶段直杆段、螺纹段和桩端截面周围土体位移场分布规律,提出了不同桩型参数螺杆桩桩周土体破坏模式。研究结果为螺杆桩设计参数优化和承载力计算理论建立提供了试验依据。

Experimental Study on Working Behavior of Vertically Loaded Screw-shaft Pile

The working behavior of the screw-shaft pile is influenced by various factors, among which the screw pitch and the screw length are two key factors. To study the progressive developing law of bearing capacity and soil deformation around vertical compression screw-shaft pile under different conditions, a model test based on digital image correlation deformation measurement is carried out, and the reliability of the model test is preliminarily verified by the field test results. The research reveals the influence law of the screw pitch and the screw length on the ultimate bearing capacity of the screw-shaft pile, and the empirical expression of normalized screw pitch diameter ratio factor and screw length ratio factor is established with reasonable values under the test condition. The distribution law of soil displacement field around the shaft section, screw section, and pile tip is concluded into different settlement stages, and the failure mode of soil around the screw-shaft pile with different pile type parameters is also proposed. The research results provide an experimental basis for the optimization of designing parameters and the establishment of the ultimate bearing capacity calculation theory of the screw-shaft pile.