Experimental Modeling of Three Dimensional Bearing Capacity of Footings on Slopes

The problem of a footing on slope is encountered regularly in engineering practice, with some noteworthy examples being bridge abutments and basement excavations. In this paper, the bearing capacity of a footing replaced near a slope crest was studied. Model tests were carried out using square model footing of 100 mm width. A tank 0.3 m deep, 0.6 m wide, and 0.9 m long was used for the model bearing capacity tests in sand. Models were prepared at different relative densities using a sand raining technique. During the tests, the density of the sand bed was adjusted by changing the height of the plate from which the sand particles freely fell. With repeated preliminary tests, reproducibility and repeatability were checked. Several parameters including the density of the soil and location of footing relative to the slope crest were studied. Particular emphasis is paid to the scale effects and its influence on bear capacity of the footing. The influence of different parameters was studied through this program and the validity of results was verified from experimental and analytical simulations. A series of upper bound limit analysis analyses were performed on a prototype slope using three-dimensional model by the computer program TRASS. The soil was represented by a non-linear perfect plastic Mohr coulomb model. A close agreement between the experimental and numerical results is observed. The rupture planes observed in the experiments and analyses were also very similar. The results show that limit analysis solutions would be a good approximation to estimate the bearing capacity of footings near slopes.