Experimental and Numerical Analysis for Earth-Fill Dam Seepage

Abstract

Earth-fill dams are the most common types of dam and the most economical choice. However, they are more vulnerable to internal erosion and piping due to seepage problems that are the main causes of dam failure. In this study, the seepage through earth-fill dams was investigated using physical, mathematical, and numerical models. Results from the three methods revealed that both mathematical calculations using L. Casagrande solutions and the SEEP/W numerical model have a plotted seepage line compatible with the observed seepage line in the physical model. However, when the seepage flow intersected the downstream slope and when piping took place, the use of SEEP/W to calculate the flow rate became useless as it was unable to calculate the volume of water flow in pipes. This was revealed by the big difference in results between physical and numerical models in the first physical model, while the results were compatible in the second physical model when the seepage line stayed within the body of the dam and low compacted soil was adopted. Seepage analysis for seven different configurations of an earth-fill dam was conducted using the SEEP/W model at normal and maximum water levels to find the most appropriate configuration among them. The seven dam configurations consisted of four homogenous dams and three zoned dams. Seepage analysis revealed that if sufficient quantity of silty sand soil is available around the proposed dam location, a homogenous earth-fill dam with a medium drain length of 0.5 m thickness is the best design configuration. Otherwise, a zoned earth-fill dam with a central core and 1:0.5 Horizontal to Vertical ratio (H:V) is preferred.

Spatial and Temporal Effects of Irrigation Canals Rehabilitation on the Land and Crop Yields, a Case Study: The Nile Delta, Egypt

“…Salmasi and Abraham [33] and Hosseinzadeh et al [8] used SEEP/W to predict the seepage from earthen channels at the Zayandeh-Rud irrigation channels, Iran. References [34][35][36][37] found that SEEP/W is a good tool to simulate the seepage from surface water to soil and vice versa. The model uses Darcy's Equation, which is expressed as:…”

Piping Potential due to springs in dam (Case study : Titab Dam)

“…Geometri bendungan meliputi kemiringan hulu dan hilir, lebar inti dan ketebalan inti berpengaruh terhadap kuantitas rembesan yang mengalir per satuan lebar, untuk bendungan inti zonal perbandingan horizontal terhadap vertikal sebesar 1:0,5 yang paling ideal (Al-Janabi et al, 2020). Koefisien permeabilitas (k), ketinggian air, kemiringan hulu (β), kemiringan hilir (α) dan lebar puncak mempengaruhi kecepatan aliran rembesan, peningkatan kecepatan aliran rembesan dapat meningkatkan gradien hidrolik (Tang et al, 2020).…”

Coupled Numerical and Analytical Stability Analysis Charts for an Earth-Fill Dam under Rapid Drawdown Conditions

“…In these cases, providing safety interactions is very effective in preventing the slope instability's occurrence [6]. The rapid drawdown in earth-fill dams is considered one of the main causes of slope failure in dam bodies [7,8] and a lack of attention to this matter eventually ends in dam failure [9]. Rapid drawdown in earthen dams demonstrates that the external water level drops so fast that impermeable soils within the earthen dam's slopes do not have sufficient time to drain.…”