Experimental And Analytical Study On The Uplift Loading Mechanism Of Strip Plate Anchors Near A Sand Slope

A large number of modern buildings require foundations to provide uplift capacity.The plate anchor foundation as a kind of anti-uplift foundation with fast construction speed,small environmental damage and saving construction cost is widely used in building construction,large suspension bridges,aircraft mooring platforms,tunnels,retaining structure,power line tower,transportation and other fields.Due to the complex environmental conditions to strip plate anchors,strip plate anchors are also often used as a pullout foundation for s tructures which are adjacent to slopes,such as mountain signal towers,offshore drilling platforms,etc.Therefore,it is of great academic and engineering significance to study the uplift capacity of the strip plate anchor which near the slope.The uplift bearing capacity of the anchor plate is mainly generated by the interaction between the anchor and the soil.In order to accurately predict the uplift capacity of the anchor,it is necessary to study the failure mechanism of the soil during the anchor is uplifted.In this study,the uplift capacity of anchor which near the slope was studied base on the model tests and the DIC image correlation technology was used to monitor the failure mode of the anchor plate foundation in the model tests.The calculation formula of the uplift capacity of anchor near which slope was proposed according to the obtained failure surfaces.The main works done in this study are listed as following:(1)The model tests were carried out and the uplift capacity of strip plate anch or adjacent to slope and buried in the flat ground was obtained.The uplift factor calculation formula of anchors buried in the flat ground and adjacent to slopes in different slope angle and edge-distance ratio were obtained.The test results show that the uplift capacity of anchor adjacent to slope was obviously reduced due to the lack of soil on the side of the slope comparing to the anchor buried in the flat ground,it also show that the uplift capacity of anchor decrease with the slope angle increased and increase with the edge-distance ratio increased.It was known that the critical edge-distance ratio existed according to results of tests,when the edge-distance ratio is greater than the critical value,the effect of the slope angle on the uplift capa city of anchor could be ignored.(2)The DIC technique was used to monitor the monitor the deformation of soil around the anchor in the model tests,the failure surfaces of the soil was obtained according to the soil displacement.The results show that the failure surfaces of both anchor which is buried in the flat ground and anchor which is adjacent to the slope are perpendicular to the edge of the anchor and then extend from the edge of the anchor to the surface of the soil;the circular curves can be used to fit the failure surfaces,the failure surfaces on both sides of the anchor buried in the flat ground are circular curves with the same radius and are symmetry;when the edge-distance ratio is smaller than the critical edge-distance ratio,the failure surfaces on both sides of anchor which is adjacent to slope are circular curves with different radius and are asymmetry;with the edge-distance ratio increased,the failure surfaces of anchor adjacent to slope begin to approach the failure surfaces of anchor buried in the ground,when the edge-distance ratio achieve the critical edge-distance ratio,the failure surfaces on both sides of the anchor which is adjacent to slope become symmetry like the failure surfaces of anchor buried in the flat ground.(3)According to the fitting failure surfaces,the limit equilibrium analysis method is used to obtain the formula for calculating the uplift capacity of anchor adjacent to sand slope.The theoretical solution based on this formula is compared with the experimental results of study and other related experimental and theoretical solutions.The comparison results verify the correctness of the theoretical formula of this study.Finally,according to the theoretical formula,the relationship between the uplift capacity of the anchor and the slope angle,the edge-distance ratio and the embedment ratio of the anchor were further analyzed.The results show that the uplift capacity increases with the anchor plate embedment ratio and the slope ratio increased,and the uplift capacity decreases with the slope angle increased.