Abstract A new method was proposed for three-dimensional analysis of the bearing capacity of shallow rectangular footing based on the modification of normal stresses over the slip surface. Firstly,the shape of the slip surface was assumed as an ellipsoid composed of a set of log-spirals with different initial radii in the direction of the longer axis of the footing base. Secondly,a method for calculating the bearing capacity of a fixed three-dimensional slip surface was established based on the modification of normal stresses over the slip surface to improve the limit equilibrium solution of 3D slope stability. Finally,the bearing capacities were obtained for the footing with selected fixed three-dimensional slip surfaces resulted from changing the positions of the pole of log-spirals so that the minimum bearing capacity was determined. The bearing capacity coefficients were then given for calculating the bearing capacity with the method of superposition in the conventional bearing capacity formula. The effects of the angle of internal friction and the length-width ratio of footing were investigated. An example was presented to calculate the bearing capacity and the calculated results were compared with those from other methods. The results demonstrate its accuracy,reasonability and high effectiveness in the three-dimensional bearing capacity analysis of rectangular shallow footing.
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Received: 27 December 2013
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