Experimental study on the behaviour of geogrid-reinforced slopes with respect to aggregate size

This paper investigates the influence of geogird reinforcement on slope deformations and its stability under a limited width of surcharge (strip footing with width of 140 mm) on the crest. A series of reduced scale plate load tests were conducted to cover different parameters including two sand-particle sizes (namely fine and coarse sands), three different lengths of geogrid reinforcement and three positions of strip footing from crest of the slope namely “edge distance”. Bearing capacity of the footing, failure mechanisms and factor of slope influence are discussed and evaluated. It is found out that the particle size of sands has great influence on the behaviour of reinforced slope and leads to change its modal behaviour especially at failure state. Based on experimental results, to achieve “plane” status conditions, regardless of the edge distance, the proper length of geogrids for fine and coarse sands were obtained 6 times of footing width (L = 6B) and 4 times of footing width (L = 4B), respectively. Also, it was observed that for fine sand, the safe edge distance of footing can be considered D = 3B. However, for coarse sand, this value might be increased to more than 3B. Particularly, critical values of studied parameters for providing maximum reinforcing effects are established.