DEM simulations of particle dissolution effects on the passive earth pressure of retaining walls

Assessing passive earth pressure is fundamental in geotechnical engineering practice. Mineral dissolution in the soil can reduce the soil strength, causing an overestimation of passive earth pressure in design. In this study, the effect of dissolution on passive earth pressure on retaining walls is investigated by using discrete element method, taking into account three modes of motion: translation (mode T), rotation around the wall bottom (mode RB), and rotation around the wall top (mode RT). The simulations show that the particle dissolution results in a significant reduction in the passive earth pressure on retaining walls. The largest reductions of resultant force are about 73.5 % and 78.5 % in modes T and RT when wall displacement is minor. Nevertheless, when the wall displacement is large, the largest reduction in resultant force is approximately 74.7 % in mode RB. A detailed analysis is provided to explain this phenomenon. Dissolution also leads to weak force chains and an increase in soil porosity, thereby weakening wall-soil interactions. Dissolution has a significant effect on passive earth pressure of lower part's soil. This study suggests that reinforcing the lower part's soil and preventing seepage in this area can help mitigate the effects of dissolution on retaining walls.