BEHAVIOUR OF SHALLOW FOOTINGS ON REINFORCED EARTH SLOPES

Abstract

For many millenniums mankind has sought various methods to construct stable soil retaining structures. In a modem context, reinforced earth has become a viable and cost- effective technique. Reinforced soil is the technique where tensile elements are placed in the soil to improve stability and control deformation. Reinforced slopes are a form of mechanically stabilized earth that incorporate planar reinforcing elements in constructed earth sloped structures. Reinforced soil slopes are cost-effective alternatives for new construction where the cost of fill, right-of-way, and other considerations may make a steeper slope desirable. Construction of a reinforced soil slope embankment at a steeper angle, road widening, slide repair, temporary flood control structures, embankment. construction with wet, fine-grained soils, reinforce the bridge abutment etc. are the various application of reinforced earth slopes. In the present investigation, the behaviour of shallow footings on reinforced and unreinforced earth slopes has been studied. Laboratory tests, (including that for unreinforced cases), were conducted by varying parameters such as the distance of footing from the edge of slope at crest, depth of top reinforcement layer, vertical spacing between reinforcement, depth of reinforcement zone and type of reinforcement. The results were then analyzed to establish both qualitative and quantitative relationship between the bearing capacity, settlement and the reinforcement parameters. The results for the reinforced system (for either the settlement or ultimate capacity) that are normalized with respect to the corresponding results derived for the footing on unreinforced slopes has been presented. The results indicate that the bearing capacity of strip footings on sloping ground can be significantly increased by the inclusion of reinforcement layers in the slope, and the magnitude of bearing capacity increase or settlement decrease depends greatly on the geogrid distribution and various parameters mentioned above. On the basis of results, critical values of the geogrid parameters for maximum reinforcing effect are suggested. Detailed results along with conclusions have been covered which will provide considerable insight and guidance to the researchers. iii