Experimental investigation into the uplift capacity of ground anchors in sand

Abstract

[Abstract]: Many modern engineering structures require a foundation system that provides adequate support by resisting loads that are imposed on the foundation of the structure or vertical and horizontal pullout forces. Stability and support of structures is provided by transferring foundational loads from the structures foundation through some form of anchors and then onto the surrounding soil and terrain. In many cases these loads and forces that are transmitted through anchors to surrounding terrain can cause the anchor to experience subsequence uplift forces. As a result, ground anchors have been developed so as to be fixed to structures and are embedded to sufficient ground depths to provide adequate amounts of support within required safety limits. It is therefore the primary focus of this project and subsequent dissertation to investigate the uplift capacity of various ground anchors in sand. Ground anchors have in fact been utilised for thousands of years in many different forms. Predominantly the use of these early anchors was to support lightweight structures only and it was not until recent times with the invention of suspension bridges that anchors were used to transfer very large loads. As a result, during the last 50 years there have been a number of studies conducted to investigate the design and use of these ground anchors. A number of theories have been developed to estimate the ultimate uplift capacity of different ground anchors in sand and it is the aim of this investigation to take a predominantly physical approach to further investigate and test this pullout phenomenon. A basic two-dimensional situation shall provide the primary focus of this investigation, however some initial investigation into three-dimensional effects shall be conducted and will therefore provide opportunity for further works in this area. The primary focus of the project is the physical of plate anchors, buried pipelines in sand and pile anchors in sand. The focus of these physical investigations shall include investigation into the failure mechanism, the load-displacement relationship, variation of peak uplift load with changing embedment ratio and variation of the break-out factor with the embedment ratio. This results shall be compared to existing results in this field. Finally, this research project will be run in cooperation with a PIV investigation and will therefore include some PIV results for these investigations.