Chapter 5
How to Conduct an Experiment
in the Field: A Portable Laboratory
Abstract Observation of the gravity erosion in the field with strong sunshine and
wind poses a challenge. Here, a novel topography meter together with a movable
tent addresses the challenge. With the topography meter, a 3D geometric shape of
the target surface can be digitally reconstructed. Two methods can be used to obtain
a relatively clear video, despite the extreme steepness of the slopes. One method is
to rotate the laser source away from the slope to ensure that the camera sightline
remains perpendicular to the laser plane. Another way is to move the camera farther
away from the slope in which the measured volume of the slope needs to be corrected;
this method will reduce the distortion of the image. In addition, the installation of
tent poles with concrete columns helps to surmount the altitude difference on steep
slopes. Results observed by the topography meter in real landslide experiments are
rational and reliable.
Keywords A portable laboratory · Field landslide experiments · Topography
meter · Slope erosion
5.1 Difficulties to Conduct a Rainfall-Simulation
Experiment in Situ
Applicable and precise instruments are vital to obtain credible data in experiments.
Recently, a structured-light 3D surface-measuring instrument, the MX-2010-G
topography meter, was designed and manufactured to observe the slope behavior
under rainfall simulation. Evaluation tests showed that the errors among the volumes
observed by the Topography meter and those of the conventional instruments were
within 10% (Xu et al. 2015). However, the above-mentioned paper was focused on
data processing and calibration testing. It did not give detailed information on the
structure of the 3D surface measuring instrument. In addition, the definition of laser
lines recorded by the camera had a high requirement for the ambient light. If the
ambient lighting was sufficiently strong, the contrast of the laser footprints would
decrease on the sloping terrain, and the image would become vague. Whether it is
possible to use the topography meter for conducting site-specific surveys of landslides
has become an urgent question to be resolved.
© Science Press and Springer Nature Singapore Pte Ltd. 2020
X. Xu et al., Experimental Erosion,
https://doi.org/10.1007/978-981-15-3801-8_5
59
How to Conduct an Experiment
in the Field: A Portable Laboratory
Abstract Observation of the gravity erosion in the field with strong sunshine and
wind poses a challenge. Here, a novel topography meter together with a movable
tent addresses the challenge. With the topography meter, a 3D geometric shape of
the target surface can be digitally reconstructed. Two methods can be used to obtain
a relatively clear video, despite the extreme steepness of the slopes. One method is
to rotate the laser source away from the slope to ensure that the camera sightline
remains perpendicular to the laser plane. Another way is to move the camera farther
away from the slope in which the measured volume of the slope needs to be corrected;
this method will reduce the distortion of the image. In addition, the installation of
tent poles with concrete columns helps to surmount the altitude difference on steep
slopes. Results observed by the topography meter in real landslide experiments are
rational and reliable.
Keywords A portable laboratory · Field landslide experiments · Topography
meter · Slope erosion
5.1 Difficulties to Conduct a Rainfall-Simulation
Experiment in Situ
Applicable and precise instruments are vital to obtain credible data in experiments.
Recently, a structured-light 3D surface-measuring instrument, the MX-2010-G
topography meter, was designed and manufactured to observe the slope behavior
under rainfall simulation. Evaluation tests showed that the errors among the volumes
observed by the Topography meter and those of the conventional instruments were
within 10% (Xu et al. 2015). However, the above-mentioned paper was focused on
data processing and calibration testing. It did not give detailed information on the
structure of the 3D surface measuring instrument. In addition, the definition of laser
lines recorded by the camera had a high requirement for the ambient light. If the
ambient lighting was sufficiently strong, the contrast of the laser footprints would
decrease on the sloping terrain, and the image would become vague. Whether it is
possible to use the topography meter for conducting site-specific surveys of landslides
has become an urgent question to be resolved.
© Science Press and Springer Nature Singapore Pte Ltd. 2020
X. Xu et al., Experimental Erosion,
https://doi.org/10.1007/978-981-15-3801-8_5
59