The influence of soil reinforcement on the uplift response of symmetrical anchor plate embedded in sand

Abstract

Uplift response of symmetrical anchor plates with and without geogrid and grid fixed reinforced (GFR) reinforcement has been evaluated in model tests and numerical simulation using Plaxis. Many items of reinforcement layers were used to reinforce the sandy soil over symmetrical anchor plate. In the current research, different factors such as relative density of sand, embedment ratios along with geogrid and GFR parameters including size, number of layers, and the proximity of the layer to the anchor plate have been investigated in a scale model. The failure mechanism and the associated rupture surface were observed and evaluated. GFR is a new tied up system with innovative design, made from fiber reinforcement polymer (FRP) which anchors the geogrid into the soil. Test results showed that using GFR reinforcement has a significant effect in improving the uplift capacity of circular anchor plates. It was found that inclusion of one layer GFR that is located resting directly on top of the anchor plate was more effective in enhancing the anchor capacity than reinforcing the geogrid or itself. It was found that inclusion of one layer of geogrid on the symmetrical anchor plate improved the uplift capacity by 19% as compared to the same symmetrical anchor plate embedded without reinforcement. However with the inclusion of GFR the uplift respond improved further to 29%. The single layer geogrid was also more effective in enhancing the uplift capacity compared to the multilayer geogrid reinforcement. On the other hand the single layer geogrid with GFR gives higher uplift capacity as compared to single layer geogrid. This is due to the additional anchorage provided by the GFR at each level of reinforcement. In general the results show that the uplift capacity of symmetrical anchor plates in loose and dense sand can be significantly increased by the inclusion of geogrid with GFR. It was also observed that the inclusion of geogrid with GFR reduces the requirement for higher L/D ratio to achieve a required uplift capacity. The laboratory and numerical analysis results are found to be in agreement in terms of break-out factor and failure mechanism pattern.