2200
Proceedings of the 18
th
International Conference on Soil Mechanics and Geotechnical Engineering, Paris 2013
10 Arresting and containing landslide debris or rockfall
10.1 Debris-resisting barrier
10.2 Rock fall barrier
10.3 Rock fall net
10.4 Debris retention basin
The following non-structural mitigation measures, reducing
either the hazard or the consequences (or vulnerability and ex-
posure of elements at risk) or in some cases both hazard and
consequence, are included in the toolbox:
a
Early warning systems
b
Restricting construction activities
c
Discouraging construction activities
d
Increasing resistance/coping capacity of elements at risk
e
Relocation of elements at risk
f
Sharing of risk through insurance
6 RANKING CRITERIA
Six criteria categories were implemented to rank the appropri-
ateness of each mitigation measure: type of movement, type of
sliding material, depth of movement, rate of movement,
groundwater, and surface water. Table 3 lists the criteria used in
the toolbox.
Table 3. Ranking criteria used for each mitigation measure
Ranking criterion
Descriptor
Type of move-
ment
Falls
Topples
Slides
Spreads
Flows
Material type
Earth
Debris
Rock
Depth of move-
ment
Superficial (< 0.5 m)
Shallow (0.5 to 3 m)
Medium (3 to 8 m)
Deep (8 to 15 m)
Very deep (> 15 m)
Rate of movement
Moderate to fast
Slow
Very slow
Extremely slow
Groundwater
Artesian
High
Low
Absent
Surface water
Rain
Snowmelt
Localized
Stream
Torrent
River
Maturity of technology
Reliability of performance
Reliability in terms of uncertainty in design
Reliability in terms of uncertainty in implementation
Safety during construction
Service life required (durability)
Aesthetics
Typical cost
7 EXAMPLE RESULT
Table 4 presents a typical result of the ranking algorithm for a
potential instability in a soft clay slope.
Table 4. Typical report from toolbox.
Rank Category
Measure
Scor
e
Most significant
parameters *
1 Surface
protection
Vege-
tated
cover
66
Material/debris
Type of movement/-flow
2 Surface
protection
Surface
drainage
65 Depth of movement
Surface water/-stream
3 Surface
protection
Infilling
of cracks
62 Surface water/stream
Rate of movement/-slow
4
Reducing
conse-
quence
Early
warning
system
36
Depth of movement/-
superficial
Material/rock
* With respect to measure appropriateness
8 SUMMARY
The paper provides only a glimpse in the toolbox. One has to
use it to actually see how it functions. The toolbox will be
available at the Safeland web site in 2013.
The purpose of web-based toolbox is to assist decision-
making and to guide the user in the choice of the most
appropriate mitigation measures. The mitigation measures are
classified into three categories, describing whether the
mitigation measures addressed the landslide hazard, the
vulnerability or the elements at risk themselves. The measures
are described in the toolbox with fact sheets providing a brief
description, guidance on design, schematic details, practical
examples and references for each mitigation measure. Each of
the measures was given a score on its ability and applicability
for different types of landslides and boundary conditions, and a
decision support matrix was established.
The web-based toolbox organizes the and provides an algo-
rithm to rank the measures on the basis of a decision support
matrix, and on the basis of the risk level estimated at the site.
9
ACKNOWLEDGMENTS
The SafeLand research was funded by the European Commission and
the authors are thankful to all their partners for their remarkable coop-
eration throughout the project.
10
REFERENCES
SafeLand (2012). Deliverable D5.1. "Compendium of tested
and innovative structural, non-structural and risk-transfer
mitigation measures for different landslide types" (rev 1-
Final dated 2011-03-31) prepared by Studio Geotechnico
Italiano S.r.l. (SGI).
SafeLand (2012). Deliverable D5.2. " Toolbox of landslide
mitigation measures" (rev 1-Final dated 2012-05-11) pre-
pared by the Norwegian Geotechnical Institute (NGI).
SafeLand website.
.
