Centrifuge modeling of axial behaviour of helical piles

螺旋桩基础广泛应用于加拿大的建筑行业。螺旋桩由一个钢管轴和一个或多个连接在轴末端的螺旋组成。与传统直桩相比，螺旋桩具有承载力大、可重复使用、安装快捷等优点；这些优点使得螺旋桩特别适用于加拿大的建筑业。近年来，加拿大的桩制造商开发了创新的螺旋桩类型，以满足日益增长的行业需求。这些桩通常直径较大，承受较大的静荷载或循环荷载。桩的设计方法尚未很好地建立或通过加载试验验证。事实上，大直径桩的原位加载试验由于桩容大，且原位试验费用过高，几乎不可能进行原位加载试验。因此，有必要对螺旋桩的原位性能进行全面的研究。**通过与加拿大螺旋桩制造商Almita桩公司合作，阿尔伯塔大学的研究小组将使用岩土离心模型试验来研究土壤-螺旋桩的相互作用。土工离心机建模是一种具有挑战性的土工和结构问题的实验室测试方法。提出的研究将开发在阿尔伯塔大学离心机上安装螺旋桩模型的技术和基础设施；本研究将在粘性土和无粘性土中进行螺旋桩模型加载试验。本研究亦会进行数值模拟以校正测试结果。拟议研究的结果将通过提供具有成本效益和可靠的实验室测试方法使工业合作伙伴受益。研究结果将促进我们对螺旋桩的性能和桩土相互作用的认识。该研究将通过提供一个有能力和经济的基础类型，使加拿大的建筑业受益。

Helical pile foundations are widely used in the construction industry across Canada. A helical pile consists of a steel tubular shaft and one or more helices attached to the end of the shaft. Helical piles have many advantages such as large capacities, reusability, and rapid installation, compared to conventional straight-shaft piles; these advantages make helical piles especially suitable for the construction industry of Canada. In recent years, innovative helical pile types have been developed by pile manufacturers of Canada to meet the increasing demand of the industry. These piles often have large diameters and are subject to large static or cyclic loads. The design methodology of the piles has not been well established or validated by loading tests. In fact, it is nearly impossible to conduct in-situ loading tests for large-diameter piles due to the large pile capacities and the prohibitive cost of in-situ tests. Hence, a research program is necessitated for a comprehensive study of the in-situ performance of helical piles. **By partnering with Almita Piling Inc., Canada's manufacturer of helical piles, the research team at the University of Alberta will investigate the soil - helical pile interaction using geotechnical centrifuge model tests. Geotechnical centrifuge modeling is a laboratory test method for challenging geotechnical and structural problems. The proposed research will develop the technique and infrastructure for installing model helical piles on the centrifuge at the University of Alberta; the research will conduct loading tests of model helical piles installed in cohesive and cohesionless soils. The research will also conduct numerical modeling to calibrate the testing results. The outcome of the proposed research will benefit the industrial partner by providing a cost-effective and reliable laboratory testing method. The outcome will advance our understanding of the performance of helical piles and the soil - pile interaction. The research will benefit Canada's construction industry by providing a capable and economic foundation type.