engleski

Initial results of the Grohovo Landslide monitoring

The Grohovo Landslide, the largest active landslide along the Croatian part of the Adriatic coast, is located on the north-eastern slope of the Rječina Valley. In 2009 the Croatian-Japanese research joint project “Risk identification and Land-Use Planning for Disaster Mitigation of Landslides and Floods in Croatia” was initiated and the Grohovo Landslide was chosen as a pilot area for monitoring system development. A comprehensive monitoring system was designed consisted of geodetical and geotechnical monitoring. Installation of monitoring equipment started in March 2011 and will be complete to the end of 2011. Integrated monitoring system will be consisted of surveying system using GPS and robotic total station, so as geotechnical monitoring using pore pressure gauges, inclinometers, extensometers and seismographs. The main part of monitoring equipment was installed in July 2011, when complete geodetical monitoring equipment was delivered and installed. In the automated integrated monitoring system until December 2011 are included observation of geodetic prisms with robotic total station and system of 10 GPS rovers (including master unit). Immediately after starting on of the system, the measurement data from the GPS and robotic total station observations were starting to collect, and it was possible to analyze initial landslide monitoring data. First analyses were pointed to relatively high accuracy and data scattering inside the expected limited values for this type of measurement and high values scattering dependence on local weather conditions. From analyzed measurement results, it is very clearly visible that the collected data are liable to numerous influences such as daily, monthly and yearly temperature and humidity variation and local disturbing effects caused by deformations of poles on whose robotic total station and GPS master unit receiver are installed. It should be necessary minimum one year of data collection that these disturbing effects could be connected with their causes and to establish procedures for calibrating equipment and eliminating effects of weather impacts on measurements accuracy. In this paper we will present the initial monitoring results so as perceived local weather condition implications on values of collected measurement data.

landslide; monitoring system; equipment; data collection; accuracy; weather condition; calibration

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