Assessment of Homogeneous Earth Dam Failure Caused by Internal Erosion: Physical Modeling and Image Processing

Earth-fill dams are widely used due to their cost-effectiveness and adaptability, yet internal erosion (piping) remains a major cause of failure. Compared to overtopping, piping has received less systematic investigation. In this experimental study, homogeneous earth dams (۴۰ cm height, ۱۴۶ cm base width, ۱۰ cm crest width) were constructed in a laboratory flume (۱۸۵ × ۶۰ × ۶۰ cm). A soil mixture of ۶۵% Firoozkooh No.۱۶۱ sand and ۳۵% silt powder was employed. To simulate preferential flow, a circular tunnel (۱۰ mm diameter) was embedded at varying elevations depending on the scenario. Two failure modes were examined to capture the breach process. High-resolution cameras monitored piping development downstream and reservoir fluctuations upstream through a transparent panel. Water was supplied from a ۶۰-liter external tank. Image processing, including edge detection, was applied to extract breach geometries and to derive water level-time, volume-time, and discharge-time relations. Flow patterns downstream were also evaluated through image analysis. Results showed that surface coating increased resistance to seepage, significantly altering erosion dynamics and breach timing. Moreover, larger upstream water volumes accelerated outflow and reservoir depletion, while continuous inflow maintained higher driving pressure, increasing erosive severity and peak discharge compared to interrupted inflow conditions.

Keywords:

Internal erosion , Piping failure , Physical modeling , Image processing