Landslide monitoring with high resolution tilt measurements at the Dollendorfer Hardt landslide, Germany

Abstract To continuously monitor ground movement at the Dollendorfer Hardt landslide in Konigswinter/Bonn, Germany, a borehole and a platform tiltmeter, both with a resolution of 0.1 µrad, were installed. The station is complemented with two pressure transducers, to control pore pressure, and four thermistors installed at different depths. Precipitation data is from Frankenforst manor, about 2 km away. The data shows clear correlation between tilt, pressure and precipitation, as well as daily temperature-induced tilt oscillations. To decompose the tilt signal, we first differentiated the series three times with respect to time to separate the trend. We then expanded the remaining signal into a Fourier series that was truncated to cutoff signal corresponding to shorter periods than 10 days. This way we separate the seasonal variation from the shorter period residual component. The trend is predominantly linear, amounting to a 1000 μrad down slope tilt per year. The residual is characterized by rainfall events. We attempt to describe the tilt response to rain by a linear system, with precipitation data as input and tilt signal as output. The analysis shows that this model qualitatively explains several features of the tilt signal, but there is also a dependence of the tilt signal on pore pressure and temperature. The study shows that a continuous, high resolution monitoring of slope deformation allows decomposition into different processes and is thus a reasonable basis to verify theoretical models.

[1]  Poroelasticity: observations of anomalous near surface tilt induced by ground water pumping , 2003 .

[2]  Thomas H. Hanna,et al.  Field instrumentation in geotechnical engineering , 1985 .

[3]  Temel Bayrak,et al.  Dynamic Model for Monitoring Landslides with Emphasis on Underground Water in Trabzon Province, Northeastern Turkey , 2003 .

[4]  M. Fabian.  Near Surface Tilt and pore Pressure Changes Induced by Pumping in Multi-Layered Poroelastic Half-Spaces. , 2004 .

[5]  Shuji Yamada.  The role of soil creep and slope failure in the landscape evolution of a head water basin: field measurements in a zero order basin of northern Japan , 1999 .

[6]  Norbert Wiener,et al.  Extrapolation, Interpolation, and Smoothing of Stationary Time Series, with Engineering Applications , 1949 .

[7]  A. Pasuto,et al.  A combined hillslope hydrology/stability model for low-gradient clay slopes in the Italian Dolomites , 1998 .

[8]  Malcolm G. Anderson,et al.  An integrated hydrological model for rain‐induced landslide prediction , 2002 .

[9]  H. Yenice,et al.  Slope stability analysis and slide monitoring by inclinometer readings: Part 2 , 2004 .

[10]  Norbert Wiener,et al.  Extrapolation, Interpolation, and Smoothing of Stationary Time Series , 1964 .

[11]  E. Bromhead.  STABILITY OF SLOPES , 1986 .

[12]  G. E. Green.  PRINCIPLES AND PERFORMANCE OF TWO INCLINOMETERS FOR MEASURING HORIZONTAL GROUND MOVEMENTS , 1974 .

[13]  H. Kümpel,et al.  Point stability at shallow depths: experience from tilt measurements in the Lower Rhine Embayment, Germany, and implications for high‐resolution GPS and gravity recordings , 2001 .

[14]  Thomas Glade,et al.  Towards Establishing Climatic Thresholds for Slope Instability: Use of a Physically-based Combined Soil Hydrology-slope Stability Model , 2004 .

[15]  M. G. Angeli,et al.  Towards the definition of slope instability behaviour in the Alverà mudslide (Cortina d'Ampezzo, Italy) , 1999 .

[16]  Duncan Carr Agnew,et al.  Strainmeters and tiltmeters , 1986 .

[17]  P. Lipman.  Natural hazards , 1993, Nature.

[18]  Ulrike Hardenbicker,et al.  Hangrutschungen im Bonner Raum : naturräumliche Einordnung und ihre anthropogenen Ursachen , 1994 .

[19]  M. Xie,et al.  A time-space based approach for mapping rainfall-induced shallow landslide hazard , 2004 .

[20]  D. Page,et al.  Ground deformation monitoring of a potential landslide at La Palma, Canary Islands , 1999 .

[21]  M. G. Angeli,et al.  A critical review of landslide monitoring experiences , 2000 .

[22]  G. Lollino,et al.  The use of the automatic inclinometric system for landslide early warning: the case of Cabella Ligure (North-Western Italy) , 2002 .

[23]  Burkhard Buttkus,et al.  Spektralanalyse und Filtertheorie , 1991 .