Applying time domain reflectometry to quantification of slope deformation by shear failure in a landslide
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This study employed time domain reflectometry (TDR) to monitor the deformation of grouted coaxial cables in a landslide over an extended period. Laboratory experiments were performed to quantify the magnitude of the deformation by shear failure to simulate types of cable deformation in the field when two localized shear types had been detected using TDR. The study applied two qualification methods to measure the magnitude of the laboratory shear deformation. The integration method of the TDR reflection coefficients demonstrated a stronger significant positive correlation with the shear displacement than did the linear regression method of reflection coefficients in relation to the deformation magnitude of the cables. The integration method indicated increases of localized shear displacements from 15 to 47 mm over time at 10.33- and 13.36-m depths in the landslide. The average maximum magnitude of the cable deformation by shearing was 47 mm corresponding to a 210-mρ reflection coefficient when the cable ruptured in the case study. Overall, the location and magnitude of shear deformation in the landslide can be determined using changes in the TDR waveforms and calculations of the integration method of reflection coefficients.
KeywordsTime domain reflectometry (TDR) Landslide monitoring Slope movement Shear testing
The field test presented in this paper could be realized through the support and sponsorship of the Soil and Water Conservation Bureau (SWCB), Council of Agriculture, Executive Yuan, Taiwan. Consecutive projects including long-term monitoring are proposed and approved by the technical counseling committee on the remediation works of the Grand Lishan landslide area, the SWCB. Furthermore, the performance evaluation of each project is periodically reviewed by the committee annually.
- Dowding CH, Pierce CE (1994) Use of time domain reflectometry to detect bridge scour and monitor pier movement. In: Proceedings of the symposium on time domain reflectometry in environmental, infrastructure, and mining applications, Evanston, Illinois, U.S. Bureau of Mines, 7–9 Sept 1994Google Scholar
- Dowding CH, Dussud ML, Kane WF, O’Connor KM (2003) Monitor deformation in rock and soil with TDR sensor cables. Geotech Instrum News 21(2):51–59Google Scholar
- Kane WF (2000) Monitoring slope movement with time domain reflectometry (TDR). Geotechnical field instrumentation: applications for engineers and geologists. University of Washington Department of Civil Engineering, KANE GeoTech Inc, pp 1–8Google Scholar
- Kane WF, Beck TJ (1996) Rapid slope monitoring. Civ Eng 66(6):56Google Scholar
- O’Connor KM, Dowding CH (1999) Geomeasurements by pulsing TDR cables and probes. CRC Press, Boca RatonGoogle Scholar
- Su MB (1990) Fracture monitoring within concrete structure by time domain reflectometry. Eng Fract Mech 35(1/2/3):313–320Google Scholar