5.2 Design of the Measurement System
65
referred to as line laser heads, were self-contained green, infrared, and red line laser
generators with an integrated laser driver circuit, optics, and laser diode. They were
suitable for different applications such as alignment, positioning, and measurement,
and were widely used in education, military, manufacturing, and medical treatment,
etc. To expediently compute the laser number on the laser source, five modules that
each emitted a red laser were set at intervals for each module that emitted a green
laser. The line laser modules were powered by the DC electrical source. The laser
line generator used in the MX-2010-G topography meter offered a compact, durable
product that was designed and built to perform reliably even under adverse industrial
conditions. The diameter of the laser head was only 1.6 cm, and the expected lifetime
was up to 10,000 h.
When the topography meter was carried to the field to conduct the site survey, the
position of the line laser module in the laser source might be changed due to the jolts
and vibrations in transit. As a result, the laser planes would become nonparallel or
the intervals of them would become unequal. Hence, we should adjust the positions
of the modules to make the lasers parallel and equidistant before commencement of
the slope behavior survey if the topography meter had been re-installed in the test
site. As shown in Fig. 5.5, the fixed bolt, which was on the module fastener, was
connected with the mainboard. To adjust the relative distance of the laser planes,
the fixed bolt should be modulated to make the fastener move back and forth on the
mainboard. The line laser module fixed in the ring of the module fastener could emit
a group of parallel laser lines. If the line laser module moved out of position, modify
the adjustable bolt to swing or rotate the line laser module slightly, and then make
the laser plane return to the parallel state.
5.3 Applications in the Landslide Experiments
5.3.1 Results of the Landslide Experiments
The landscape simulator consisted of a rainfall simulator and a slope model covering
an area of 3.0 m × 3.0 m. An experimental model landscape, with a steep slope of
60°–80° and the gentle slope of 3°, was made of loess by hand patting. The conceptual
landscape in the field was “cut” without disturbing the slope underground. In other
words, the initial landform in the field study kept the original texture and density,
although the surface was cut to be smooth. Underlying the surface of the tested slope
was a kind of sandy Holocene loess. The dry bulk density ρ d was 1.54 g/cm
3 and the
median size d 50 was 143.0 µm. A short and intense downpour, with an intensity of
0.8 mm/min and a duration of 60 min, was applied. In turn, 5–10 events of rainfalls
were applied to the slope. An equal period, 12 h or so, was kept after each rainfall to
ensure the approximate value of initial water content. The MX-2010-G topography
meter was used to monitor the mass movement of the failure surface under rainfall
simulation (Fig. 5.1b). Furthermore, a large tent was set up in the experimental
65
referred to as line laser heads, were self-contained green, infrared, and red line laser
generators with an integrated laser driver circuit, optics, and laser diode. They were
suitable for different applications such as alignment, positioning, and measurement,
and were widely used in education, military, manufacturing, and medical treatment,
etc. To expediently compute the laser number on the laser source, five modules that
each emitted a red laser were set at intervals for each module that emitted a green
laser. The line laser modules were powered by the DC electrical source. The laser
line generator used in the MX-2010-G topography meter offered a compact, durable
product that was designed and built to perform reliably even under adverse industrial
conditions. The diameter of the laser head was only 1.6 cm, and the expected lifetime
was up to 10,000 h.
When the topography meter was carried to the field to conduct the site survey, the
position of the line laser module in the laser source might be changed due to the jolts
and vibrations in transit. As a result, the laser planes would become nonparallel or
the intervals of them would become unequal. Hence, we should adjust the positions
of the modules to make the lasers parallel and equidistant before commencement of
the slope behavior survey if the topography meter had been re-installed in the test
site. As shown in Fig. 5.5, the fixed bolt, which was on the module fastener, was
connected with the mainboard. To adjust the relative distance of the laser planes,
the fixed bolt should be modulated to make the fastener move back and forth on the
mainboard. The line laser module fixed in the ring of the module fastener could emit
a group of parallel laser lines. If the line laser module moved out of position, modify
the adjustable bolt to swing or rotate the line laser module slightly, and then make
the laser plane return to the parallel state.
5.3 Applications in the Landslide Experiments
5.3.1 Results of the Landslide Experiments
The landscape simulator consisted of a rainfall simulator and a slope model covering
an area of 3.0 m × 3.0 m. An experimental model landscape, with a steep slope of
60°–80° and the gentle slope of 3°, was made of loess by hand patting. The conceptual
landscape in the field was “cut” without disturbing the slope underground. In other
words, the initial landform in the field study kept the original texture and density,
although the surface was cut to be smooth. Underlying the surface of the tested slope
was a kind of sandy Holocene loess. The dry bulk density ρ d was 1.54 g/cm
3 and the
median size d 50 was 143.0 µm. A short and intense downpour, with an intensity of
0.8 mm/min and a duration of 60 min, was applied. In turn, 5–10 events of rainfalls
were applied to the slope. An equal period, 12 h or so, was kept after each rainfall to
ensure the approximate value of initial water content. The MX-2010-G topography
meter was used to monitor the mass movement of the failure surface under rainfall
simulation (Fig. 5.1b). Furthermore, a large tent was set up in the experimental