XXIX-B8, 2012
(plain before can give
Vz
83 -0.0365
93 -0.0569
09 -0.0022
00 -0.0013
84 0.0857
49 -0.0732
26 -0.0428
68 0.0295
95 0.0184
09 0.0308
05 0.0288
75 0.0034
33 0.0163
83 -0.0365
93 -0.0569
transformation of the
second campaign.
SCUSSION
erence system we can
with point clouds or
zones in the road cut
y were generated as a
ffecting to the region
r. This unstable zone
material that invaded
ighway and produced
oblems. Besides, the
red campaigns; it can
f both surfaces, with
formation of steps,
, some superficial
roughly measured by
obtaining maximum
both campaigns that
day.
errain and vegetation
tudied road cut.
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B8, 2012
XXII ISPRS Congress, 25 August — 01 September 2012, Melbourne, Australia
On the other side, displaced volumes have been calculated by
means of the software tools applied in this case to DEMs. In the
figure 8, depletion and accumulation zones are shown.
Depletion zones are those in which the surface corresponding to
the second campaign is under the surface corresponding to the
first campaign and accumulation zones are those in which the
second surface are over the first surface. The obtained numeric
results to the zone B are shown in table 2.
Mobilized Depletion Accumulation ~~ Wasting
material
Volume (m?) 210,02- 124,50 85,52
Rates (m? day!) 15,00 8,89 6,10
Table 2. Volume calculations of mobilized material to zone B.
These calculations gives first results of 210 m? of depleted
material) and 124,5 m? of accumulated material. The differences
between these volumes (wasting material) are explained
because of the material removed by civil works as well that
occupying the highway as that resulting of the advance of the
road cut to the road. This material was removed due to the
actuation carried out by the State Public Administration with the
objective of stopping the landslide affecting the highway. The
works started after the first campaign, which explains the large
amount of wasting material between both campaigns; they
consisted in removing material in the slope toe and put a
contention wall to stabilize the mobilized mass.
Figure 8. DEM surface corresponding to the second campaign:
in orange, those zones in which this surface are under the first
campaign surface (depletion); in blue, those zones in which this
surface is over the first surface (accumulation). Top: front view;
center: plan view; bottom: unstable zones details (zone A at the
left and zone B at the right)
7. CONCLUSIONS AND FURTHER WORKS
Terrestrial laser scanning techniques are proved again as a very
useful tool to study landslide and its temporal evolution. In this
sense they are becoming one of the most used tools to
deformation monitoring because it gives a high density and
spatial accuracy data in a short time interval.
In this work we present a methodology to georeferencing TLS
data to multi-temporal studies about landslides monitoring,
applied in this case to an unstable mass in a road cut that flows
over a national highway, causing important traffic problems. In
these studies, it is very important to establish a stable reference
framework or system to monitoring terrain deformations and to
measure displacements. However, the poor accessibility of the
zone makes difficult to include targets in the study area and the
general instability does not allow identifying stable areas. So,
ETRS89 was used as the reference framework and TLS data are
georeferenced by means the measurement of scan stations
coordinates by means GPS observations. After that, a weighted
rigid 3D transformation has been applied to transform the point
clouds from a local reference system to the ETRS89 system.
This methodology has allowed monitoring the landslide
occurred in the studied area in 2009/10 winter as a consequence
of heavy rainfalls that became twice the mean precipitations in
this period. The landslide was measured by means TLS
instrument in a period of 14 days in which important
modifications in the terrain surface could be observed. All the
field works to data capture have been carried out in a short
period of time (a few hours).
The obtained results are maximum superficial displacements of
about 8-9 m in the terrain and vegetation between the two
campaigns that produces a daily rate of about 0,55-0,65 m day’.
Regarding mobilized volumes, we estimate about 210 m? of
depleted material and 124,5 m? of accumulated material; the
differences between these volumes (wasting material) are
explained because of the material removed by civil works to
recovery the traffic of the highway.
The stable and global reference system established in this work
can be used to multitemporal analysis to data captured until this
moment and those that can be captured in further works. Further
works will be on the refinement of this methodology and
integration with other techniques such as close range
photogrammetry, aerial photogrammetry and airborne LiDAR
to multi-temporal and multi-scalar analysis, developed in the
research project that will be mentioned above.
8. REFERENCES
Abellán, A., Vilaplana, J.M. and Martínez, J., 2006. Application
of a long-range Terrestrial Laser Scanner to a detailed rockfall
study at Vall de Nüria (Eastern Pyrenees, Spain). Engineering
Geology, Elsevier, 88:136-148.
Abellán, A., Jaboyedoff, M., Oppikofer, T. and Vilaplana, J.M.,
2009. Detection of millimetric deformation using a terrestrial
laser scanner: experiment and application to a rockfall event.
Nat. Hazards Earth Syst. Sci., 9: 365-372.
Bu, L. and Zhang, Z., 2008. Application of Point Clouds from
Terrestrial 3D Laser Scanner for Deformation Measurements.
The International Archives Of The Photogrammetry, Remote
Sensing And Spatial Information Sciences. Vol. XXXVII. Part
B5. Beijing 2008, 545-548.
Cardenal, J., Delgado, J., Mata, E; González-Díez, A., Remondo,
J., Diaz de Terán, J.R., Francés, E., Salas, L., Bonachea, J.,
Olague, L, Felicisimo, A., Chung Ch.J., Fabbri, A. and Soares,
A., 2006. The use of digital photogrammetry techniques in
landslide instability. In Geodetic Deformation Monitoring:
From Geophysical to Geodetic Roles, (Gil Cruz and Sanso,
Eds.). IAG Springer Series, 259-264.
