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Know-how
Researching natural hazards
with the help of METTLER TOLEDO products
It can’t be denied anymore: Global
climate change is a reality. Until recently,
it seemed to be just another doomsday
scenario promoted by crazy environmentalists. But the alarming truth of global
warming is now recognized by a variety
of interest groups worldwide. And the
recently published UNO Climate Report
backs their views with historical facts.
Switzerland, 2002.
One of the more visible effects of climate change in the recent past has
been the high number of extreme
weather incidents. A good example is
the extraordinarily heavy rainfall over
the last few years that has caused so
many floods and landslides – including right here in Switzerland. The
influence of climate on the stability of
embankments is now being studied by
the Technical University of Rapperswil
(HSR) in cooperation with Nanyang
Technological University (NTU) in
Singapore.
What are they studying?
The landslide model is being used to
study the level of impact of climactic
changes on the stability of hillslopes.
In this study, scientists are particularly
interested in the reaction of the capillary forces in the soil on the intensity
and duration of precipitation, as well
as previous rain events.
The groundwater flow within a hillslope is considered to be another
stability factor. The stratigraphical
arrangement of the soil influences the
groundwater flow through more or
less permeable rock beds. Groundwater
simulations were conducted to study
this action more closely. Measurements
The landslide model is a 2.00 x 0.60 x 1.80m box made of steel and acrylic panels with a model hillslope. The rain unit installed in the
cover can be operated with different intensities, while the groundwater is directed over clefts on the face of the wall and behind it. The
slope of the model can also be set using an hydraulic cylinder.
11
Landslide Bormio, Italy, 1987
Bavaria, Germany, 1988
of the pore pressures and the water
content immediately before a landslide
yield information about the fracture
behavior of an embankment.
Scales and data transfer software
from METTLER TOLEDO
Groundwater and surface run-off is
continuously recorded using METTLER
TOLEDO scales. With the BalanceLink
software, also from METTLER TOLEDO,
these scale values are then directly
transferred to a computer and simultaneously filed in an Excel table.
Later in the study, piezometers will
monitor the flow of the water table.
Tensiometers will be used to measure
the pore water pressure in the soil at
several measuring points, and data loggers will send the data to the computer.
The water content will also be measured using time domain reflectometry
(TDR) and the data likewise transferred
to the computer.
The goal of the research project is
to make more precise predictions
regarding future landslides. A key
benefit will be the ability to warn
the populations of high-risk areas
earlier and more effectively.
www.mt.com
For more information
Mettler-Toledo AG
CH-8606 Greifensee, Switzerland
Phone +41-44-944 22 11
Fax +41-44-944 30 60
Subject to technical changes, © 04/2007 Mettler-Toledo AG, MarCom Industrial