Engineers Australia

Technical Note On Pseudo-Static Seismic Pressure Applied To Retaining Walls With Linear Surcharge In C-Ø Soils

Mojtaba Ahmadabadi, Mohammad Karim Faghirizadeh and Gholamreza Namvarchi


This study has explored seismic pressure applied to retaining walls with linear surcharge effect in cohesive-frictional soils, assuming three general approaches. The first approach provides a formulation. This formulation is able to calculate the seismic pressure, the seismic pressure coefficient, and the angle of failure wedge. The second approach provides dimensionless graphs for designers. There are three general graphs for calculating the seismic pressure applied to the wall and four graphs for determining the minimum and maximum seismic pressure levels. The lower limit of each graph shows the minimum active soil pressure coefficient (kase(min)) at the lowest surcharge distance, and the upper limit shows the maximum active soil pressure coefficient (kase(max)) at the highest surcharge distance from the wall. Five comprehensive graphs are presented to determine the angle of failure wedge. These graphs show the changes in the internal friction angle of the soil, cohesion, linear surcharge, horizontal acceleration coefficient, surcharge distance from the wall, and the friction angle between the soil and wall. In the third approach, all specific and unique wall analyses can be performed by referring to MATLAB software and using programming codes. Compared to other methods, the proposed method has the advantage of considering soil parameters such as cohesion, soil internal friction angle, friction angle between the soil and wall and linear surcharge in elasto-plastic soil and in seismic conditions. Other advantages include the calculation of excess stress distribution due to surcharge, the distribution of total seismic stress, and the calculation of depth of tensile crack. Comparison of the results of the proposed method with previous methods and numerical software shows the accuracy of relationships and graphs.