Seepage Simulation Analysis for Isotropic Soils of Homogeneous Embankment Dams

Abstract

SEEP/W is a sophisticated finite element program for simulating groundwater flow in porous media. SEEP/W can also model simple saturated steady-state problems as well as complicated saturated/unsaturated transient analysis. This study aims to determine the effects of the different types of isotropic soils on the seepage and exit gradient of homogeneous earth dams through using seepage analysis simulation. A total of sixty simulations were performed to determine the effects of each six different types of isotropic soil, including gravel, silt, silty sand, silty clay, clay and sand, on the seepage and exit gradient of homogeneous earth dams. In the simulation data, the highest value of the exit gradient is from gravel, which is 0.50003672, while the lowest value is from clay, with a value of 0.500029. In seepage flux, gravel and clay soil have the highest and lowest values, with a minimum and maximum value of $3.00E-04m^{3}/s$ and $3.00 E-02 m^{3}/s$ for gravel and $1.00 E-11 m^{3}/s$ and $4.70 E-09 m^{3}/s$ for clay,, respectively. The computed r-value is 0.623 and the tabular value is 0.2546766 with 58 degrees of freedom and a 0.05 level of significance. Due to the r-value of 0.623, which is in between the r-values of 1.0 and 0.5, the seepage and exit gradient have a Positive Relationship in terms of Pearson's Correlation Method. Based on this data, it is highly recommended to use clay soil for designing embankment dams as it has low value for both seepage and exit gradient which could prevent piping. While gravel should be avoided among the six types of soil that were simulated since it has a high value for both seepage and exit gradient, making it more susceptible to piping which is one of the major causes of dam failure.