Optimizing Performance of Location for Horizontal and Chimney Drainage of Earthen Slopes Retaining Walls on Stability

Abstract

Underground water levels and pore water pressure can be increased as a result of heavy rainfall which can lead failure of earthen slopes. Retaining walls are the most well-known structures in order to increase earthen slope stability. In this study, the stability of earthen slopes is numerically simulated in critical hydrological situations. The simulations included pore pressure behind the retaining walls which lead to instability. Among the investigated parameters were: precipitation intensity, soil type, position and the diameter of drainage passages. Both horizontal and chimney drainages were simulated for the study. For fine-grained soils with intensive precipitation, using a single horizontal drainage passageway could not maintain sufficient stability for the retaining wall. Precipitation could have severe impact on stability in which increase of 5 to 15 mm/h would increase pore pressure from 7.09 kN to 75.39 kN which is so dramatic change. For coarse-grained soils, a retaining wall provides stability with a single horizontal drainage pipe; the horizontal pipe is able to discharge all the excess water behind the retaining wall. A chimney drainage system provided the best results, and the stability of the retaining wall did not endanger, even under the worst circumstances. Linear and non-linear regression relations were produced in dimensionless form which are providing 0.97 for R2 and 0.11 for RMSE values which implys the accurcy of equations. The accuracy of the regression determine their usage in practical applications.