5
The focus for the next test was mainly to study seepage
in soil. In this experiment, the bottom chamber was entirely
filled with water. A dye was poured in the upslope chamber
and water level allowed to rise and flow through the soil
slope. A night mode is set and an ultraviolet (UV) flashlight
flashed along the water path through the soil (Figure 7).
The use of the dye would help tracing the water path as it
moves through the soil. Since a night mode is simulated,
the UV flashlight was able to detect its path. Finally, a 4K
camera is set to film the process for further studies.
3.6 Visual monitoring
A camera was set up to monitor the seepage front using
a 4K camera and a dye. The camera recorded the satura-
tion process for seepage and slope movement throughout
the experiment. These processes were then compared to the
numerical modeling results. The camera was a Sony AX33
4K Handycam (Figure 8). Table 1 shows the technical spec-
ifications of the video camera.
Figure 7. Set up for experiment with the camera and dye
Table 1. Specifications of the video camera
Parameter Camera
Model Sony AX33 4K Handycam
Effective pixels (video) Approximately 8.29 megapixels
Effective pixels (still image) Approximately 10.3 megapixels
focal length 29.8-298.0 mm
Lens Filter diameter 52 mm
4.0 RESULTS AND DISCUSSION
4.1 Introduction
With laboratory experiments undertaken with pictures of
initial conditions and aftermath after failures, the numeri-
cal modeling analysis can take place. Numerical models
such as Finite Element methods can help simulate slope
failures with factor of safety, pressure heads, flow lines, and
flow vectors. These experimental works were modeled in
the finite element software, and the results were compared
to the small-scale slope at the laboratory.
Laboratory experiments for slope failure. The results
of the experiments conducted with different scenarios
are discussed in this section. In total, four slope stability
experiments were conducted with other initial conditions.
Experiments 1 and 2 showed similar visual results during
the entire time. The first scenario was a steady-state condi-
tion with water at the bottom of the chamber (Figure 9),
and the second simulated a gradual water rise, which typi-
cally represents a tailings dam. The last two (2) focused on
the ratio of water level and slope failure (Figure 9).
With water level kept constant at a level of 190 mm
of the total slope height of 220 mm, water was allowed to
seep through the perforations from the upslope water tank
through the soil into the downslope tank. Wetting was seen
at the toe of the slope very quickly about 2 minutes from
the start of the test. Bulging and pressure ridges at the toe
started when the toe was very saturated. This lateral move-
ment was due to pressure build-up from the water seepage.
From the 10th minute, tension cracks were spotted close to
the toe of the slope, which eventually propagated upslope.
The shear stress of the toe diminished, and this made the
Figure 6. Box of soil sample before gradual water rise
experiment
Figure 8. The camera for digital video recording
The focus for the next test was mainly to study seepage
in soil. In this experiment, the bottom chamber was entirely
filled with water. A dye was poured in the upslope chamber
and water level allowed to rise and flow through the soil
slope. A night mode is set and an ultraviolet (UV) flashlight
flashed along the water path through the soil (Figure 7).
The use of the dye would help tracing the water path as it
moves through the soil. Since a night mode is simulated,
the UV flashlight was able to detect its path. Finally, a 4K
camera is set to film the process for further studies.
3.6 Visual monitoring
A camera was set up to monitor the seepage front using
a 4K camera and a dye. The camera recorded the satura-
tion process for seepage and slope movement throughout
the experiment. These processes were then compared to the
numerical modeling results. The camera was a Sony AX33
4K Handycam (Figure 8). Table 1 shows the technical spec-
ifications of the video camera.
Figure 7. Set up for experiment with the camera and dye
Table 1. Specifications of the video camera
Parameter Camera
Model Sony AX33 4K Handycam
Effective pixels (video) Approximately 8.29 megapixels
Effective pixels (still image) Approximately 10.3 megapixels
focal length 29.8-298.0 mm
Lens Filter diameter 52 mm
4.0 RESULTS AND DISCUSSION
4.1 Introduction
With laboratory experiments undertaken with pictures of
initial conditions and aftermath after failures, the numeri-
cal modeling analysis can take place. Numerical models
such as Finite Element methods can help simulate slope
failures with factor of safety, pressure heads, flow lines, and
flow vectors. These experimental works were modeled in
the finite element software, and the results were compared
to the small-scale slope at the laboratory.
Laboratory experiments for slope failure. The results
of the experiments conducted with different scenarios
are discussed in this section. In total, four slope stability
experiments were conducted with other initial conditions.
Experiments 1 and 2 showed similar visual results during
the entire time. The first scenario was a steady-state condi-
tion with water at the bottom of the chamber (Figure 9),
and the second simulated a gradual water rise, which typi-
cally represents a tailings dam. The last two (2) focused on
the ratio of water level and slope failure (Figure 9).
With water level kept constant at a level of 190 mm
of the total slope height of 220 mm, water was allowed to
seep through the perforations from the upslope water tank
through the soil into the downslope tank. Wetting was seen
at the toe of the slope very quickly about 2 minutes from
the start of the test. Bulging and pressure ridges at the toe
started when the toe was very saturated. This lateral move-
ment was due to pressure build-up from the water seepage.
From the 10th minute, tension cracks were spotted close to
the toe of the slope, which eventually propagated upslope.
The shear stress of the toe diminished, and this made the
Figure 6. Box of soil sample before gradual water rise
experiment
Figure 8. The camera for digital video recording