Volume 6, Issue 3 (September 1983)
Laboratory Pull-Out Testing of Grid Reinforcements in Sand
In many reinforced soil applications the critical mode of failure involves pull-out of the reinforcement from the soil. Although grid reinforcement is known to be very efficient in resisting pull-out failure, very little is published on the mechanisms of soil-grid interaction. To investigate soil-grid behavior, several series of pull-out tests were conducted using both metallic and plastic grids embedded in sand. The results of these tests are presented in this paper together with details of the apparatus and testing techniques used. Results are also given for ancillary testing carried out to assess the effects of grid member orientation with respect to the direction of the applied pull-out load. These tests clearly demonstrate that pull-out resistance is a function of the cumulative embedded area of the grid members normal to the direction of pull-out and not the embedded plan area of the reinforcement. Based on these observations an analytical model is developed for strong inextensible grids. Analytical and test results are compared and found to be in good agreement for both metallic and plastic grids.