عنوان مقاله [English]
Geosynthetics have been extensively used as soil reinforcements under footings especially in soft grounds. Geocell is a form of three-dimensional reinforcement which is able to provide greater bearing capacity due to confinement compared to planar types of reinforcements like geogrids and geotextiles. On the other hand, using tire shreds, in addition to improving soil properties would have favourable environmental effects that causes a great tendency for its utilization in engineering projects. In order to study the cyclic and post-cyclic behaviours of strip footings on sands reinforced by geocells and rubber particles, a small-scale physical model in soil mechanics laboratory of Amirkabir University of Technology has been developed. Main parts of the laboratory apparatus include the footing model, the soil container, raining system, loading equipment and data acquisition system. Geocells with
different geometrical dimensions, yet the same material have been used in a specific location in sand layers. To investigate the effect of rubber particle size mixed with sand as the geocell infill material, the geocell pockets have been filled with different materials; namely pure sand, pure rubber particles and mixture of rubber particles and sand at desired densities. Then a static loading is applied to the footing followed by a cyclic loading up to 1000 load cycles. Finally, the static loads are re-applied until failure occurs. The study's results indicate that in similar compaction condition, substituting a percentage of sand with rubber particles of greater size leads to reduction in plastic settlement and increment in elastic settlement. In the case of mixing sand with rubber powder with the smaller particle size, the settlement would increase while the bearing capacity decreases. Therefore, it is concluded that using the mixture of soil and rubber particles of greater particle sizes compared to soil grains would improve the cyclic behaviour of reinforced soil by decreasing the permanent or plastic settlements.