Bearing Capacity of Reinforced Sand Subgrades

Laboratory bearing capacity model tests were performed on both reinforced and unreinforced sand loaded by a strip footing. The effects of soil density and reinforcing strip length were investigated. The tests show that a significant increase in bearing capacity can be achieved at relative densities between 51 and 90% by the use of metal reinforcing strips. Bearing capacity of reinforced sand is a strong function of the length of the reinforcing strips only until the strip length reaches approximately seven times the footing width; additional length does not significantly increase bearing capacity. For those tests on unreinforced sand where a distinct peak in the load-bearing pressure curve occurs (general shear failure), the failure of the corresponding reinforced sand occurs at a larger settlement. A comparison of test results with an analytical method of predicting bearing capacity of reinforced sand shows the importance of the soil-reinforcing strip friction coefficient.