One problem that often occurs in dams
is the flow of water seepage on the body of the dam. Thus, seepage analysis
needs to be used to observe the seepage flow pattern and the seepage discharge
from the dam's body. In this research, the physical model of a homogeneous fill
dam planned in trapezoidal
form, the slope of 30 degrees with 90 percent density level. The dimensions of
this dam are 3200 cm, height 880 cm, and side width 1760 cm. The drainage
installed in the downstream of the dam within 1200 cm of the length and 80 cm
of height which used gravel sand material. The variations heights of storage
water are 800 cm, 700 cm, 600 cm, 500 cm, 400 cm, 300 cm, and 260 cm. This
variation carried out to study the effect height on water seepage patterns.
Based on the USCS (Unified Soil
Classification System) is that the soil classified as SP (clean sandy soil)
with a permeability coefficient of 2.04 x 10 -3 cm/sec. The results of soil
testing are being
used in the calculation of seepage
discharge by three methods, namely the empirical method (physical model),
Casagrande method, and Geo
Studio
2012 Seep/w software.
The conclusion of this research that the higher the storage water in upstream,
the seepage discharge downstream will be high. Otherwise, if the storage water
in upstream is low, then the seepage discharge downstream will be small.
Keywords: Seepage, Homogeneous Fill Dam, Physical Model, Casagrande, Geo Studio 2012 Seep/w Student Version.