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The results of the laboratory investigation performed on clay beds reinforced with natural (bamboo) and commercial (geosynthetics) reinforcement materials are reported in this paper. To use bamboo effectively, three-dimensional cells (similar to geocells) and two-dimensional grids (similar to geogrids) are formed using bamboo (termed bamboo cells and bamboo grids, respectively). The performance of clay beds reinforced with bamboo cells and bamboo grids is compared with that of clay beds reinforced with geocells and geogrids. The bearing capacity of the clay bed increased by six times when a combination of geocell and geogrid was used. The ultimate bearing capacity of the clay bed reinforced with bamboo cell and bamboo grid was found to be 1.3 times more than that of clay bed reinforced with geocell and geogrid. In addition, substantial reduction in the footing settlement and the surface deformation was observed. The tensile strength and surface roughness of bamboo were found to be nine times and three times, respectively, higher than geocell materials. The bamboo was treated chemically to increase its durability. Although the performance of bamboo was reduced by 15-20% after the chemical treatment, its performance was better than its commercial counterparts. [ABSTRACT FROM AUTHOR]

The effect of a base geogrid layer below the geocell mattress in sand, sand overlying soft clay, and soft clay foundation beds has been studied using a series of laboratory scale load tests. A rigid circular model footing was used to apply static monotonic loading on the foundation beds with and without geocell reinforcement. The model test results show that the provision of an additional layer of planar geogrid at the base of the geocell mattress further increases the performance of the footing in terms of bearing capacity and reduction in surface heave of the foundation bed. It is also observed that the beneficial effect of the base geogrid layer becomes negligible with increasing height of the geocell mattress beyond the influence of the depth of the footing. Strain measurements in the base geogrid layer indicate that it is more effective with the limited heights of the geocell mattress. The earth pressure cells embedded in the subgrade soil provide evidence that when the base geogrid is provided below the geocell mattress, the footing pressure is distributed more uniformly over an extended area. [ABSTRACT FROM AUTHOR]

This paper describes laboratory model tests to determine the bearing capacity of an embedded circular footing supported by multiple layers of geogrid-reinforced sand beds. The embedment depth ratio of the footing was varied from zero to 06. The tests were conducted with one variety of geogrid in sand compacted to 70% relative density. Besides load settlement data, deformations on fill surface, strain in geogrid layer and pressure distribution in soil subgrade (below the geogrid layers) were measured. The test results demonstrate that the ultimate bearing pressure increases with embedment depth ratio of the foundation. With the provision of multiple layers of geogrid reinforcement in the sand bed, high-performance improvement is obtained, in terms of both increase in bearing capacity and reduction in surface deformation. Also, the footing pressure is redistributed more uniformly over a wider area on the subgrade soil. Strain measurements in the geogrid layers indicate that the geogrid reinforcement is more effective in the region below the footing width. [ABSTRACT FROM AUTHOR]

Laboratory model test results for the bearing capacity of circular footings supported by geocell-reinforced sand beds are presented. Footing load-settlement response, deformations at the fill surface, strains in the geocell wall and pressure distributions below the geocell mattress were measured. The test results demonstrate that significant performance improvement can be obtained in terms of both increased bearing capacity and reduced surface deformation by providing geocell reinforcement in the sand bed. Pressure measurements indicate that the footing pressure is redistributed more uniformly over a wider area on the subgracle soil, indicating that the geocell-reinforced sand bed behaves as a composite mass. [ABSTRACT FROM AUTHOR]