Comparative analysis of horizontal and pipe drains in earth dams: optimizing seepage control and stability (case study)

Abstract

This study presents a comparative analysis of horizontal and pipe drains in earth dams, focusing on optimizing seepage control and stability. Using the Kreireche dam in Algeria as a case study, we employed GeoSlope software (SEEP/W and SLOPE/W) to conduct numerical simulations across 20 different scenarios, varying drain configurations and hydraulic conditions. Results indicate that pipe drains significantly outperform horizontal drains in managing seepage and enhancing dam stability. Pipe drains with larger diameters (2 m) reduced pore pressure by 15–20% compared to horizontal drains, demonstrating superior seepage control. Optimal drain placement within the range of X/B = 0.2 to 0.4 led to maximum safety factors, highlighting the importance of drain positioning. Statistical analysis using RMS, MAE, and MSE metrics showed that pipe drains consistently provided more reliable seepage and exit gradient control compared to horizontal drains. Increasing pipe drain diameter from 1 m to 2 m improved discharge seepage prediction consistency, reducing normalized RMS and MAE by 18.5% and 17.3%, respectively. Pipe drains exhibited 64.2% lower normalized RMS values for exit gradient predictions compared to horizontal drains, indicating more effective erosion risk mitigation. This study provides important insights for enhancing drainage system design in earth dams, resulting in increased stability and long-term performance of these crucial water management structures.