Three-dimensional active earth pressure coefficients by upper bound numerical limit analysis

A 3D numerical implementation of the limit analysis upper bound theorem is used to determine active horizontal earth pressure coefficients. Results of the ratio between the 3D and 2D horizontal active earth pressure coefficients for both soil weight and surcharge are shown and found to be almost independent of the soil-to-wall friction ratio, as is the case with passive earth pressure coefficients. A simple equation is proposed for calculating this active earth pressure ratio and it is compared with previously published results.