Behaviour of tapered screw pile foundations in unfrozen soils

加拿大多年冻土区基础设施的传统基础是直轴桩，这不是一个优化设计的研究人员和从业人员。加拿大北方的快速经济增长增加了对基础设施系统的新建设和维护的需求，这需要更安全但经济的基础。拟议的研究引入了一种创新的基础类型，锥形螺旋桩（也称为地螺钉），作为传统桩基的替代方案。由于特殊设计的轴，接地螺钉 ** 表现出上级性能，如大轴向能力，易于安装和可重复使用。 然而，在永久冻土或未冻结的土壤中的地面螺钉的性能仍然没有很好的工程和永久冻土中的地面螺钉的设计指南是不存在的。这项研究将填补这一研究空白。通过与Thugga Ltd.合作，该研究小组将系统地研究埋入未冻和冻土中的地钉的轴向和横向行为;确定荷载传递和破坏机制;研究地钉在永久冻土中的短期和长期性能;并优化安装技术。为了实现这些目标，该团队将对安装在加拿大西部典型未冻土和加拿大北方典型冻土中的接地螺钉进行现场测试。该团队将对承受轴向载荷的螺杆段进行实验室测试，开发模拟土壤-螺杆相互作用的数值模型，并提出设计指南。拟议研究的结果将有助于工业合作伙伴扩大接地螺钉在加拿大现有和新兴行业的应用。这项研究将促进我们的理解的性能的地面螺丝和土壤螺丝的相互作用在解冻和冻结的环境。这项研究将通过提供一个有能力和经济的基础类型，使加拿大的基础设施系统受益。

Conventional foundations for infrastructure in Canada's permafrost regions are straight-shaft piles, which are not an optimized design as shown by researchers and practitioners. Quick economic growth in Northern Canada has increased the need for new construction and maintenance of infrastructure systems, which require more safe yet economic foundations. The proposed research introduces an innovative foundation type, tapered screw piles (also known as ground screws), as an alternative to the conventional pile foundation. As a result of the specially designed shaft, ground screws have **shown superior behaviour such as large axial capacities, ease of installation, and reusability. However, the performance of ground screws in permafrost or unfrozen soils are still not well engineered and design guidelines for ground screws in permafrost are nonexistent. The proposed research will bridge this research gap. By partnering with Thugga Ltd., the research team will systematically investigate the axial and lateral behaviour of ground screws embedded in unfrozen and frozen soils; identify the load-transfer and failure mechanisms; investigate the short-term and long-term performance of the **ground screws in permafrost; and optimize the installation technique. To fulfill the objectives, the team will conduct in-situ tests of ground screws installed in typical unfrozen soils in Western Canada and typical frozen soils in Northern Canada. The team will conduct laboratory testing of screw segments subject to axial loading, develop numerical models for simulating soil-screw interactions, and propose a design guideline. The outcome of the proposed research will help industrial partner expand the applications of ground screws in existing and emerging industries across Canada. The research will advance our understanding of the performance of the ground screws and soil-screw interactions in unfrozen and frozen environments. The research will benefit Canada's infrastructure systems by providing a capable and economic foundation type.**