Displacement of a landslide retaining wall and application of an enhanced failure forecasting approach

Abstract

The 10-mile Slide is contained within an ancient earthflow located in British Columbia, Canada. The landslide has been moving slowly for over 40 years, requiring regular maintenance work along where a highway and a railway track cross the sliding mass. Since 2013, the landslide has shown signs of retrogression. Monitoring prisms were installed on a retaining wall immediately downslope from the railway alignment to monitor the evolution of the retrogression. As of September 2016, cumulative displacements in the horizontal direction approached 4.5 m in the central section of the railway retaining wall. After an initial phase of acceleration, horizontal velocities showed a steadier trend between 3 and 9 mm/day, which was then followed by a second acceleration phase. This paper presents an analysis of the characteristics of the surface displacement vectors measured at the monitoring prisms. Critical insight on the behavior and kinematics of the 10-mile Slide retrogression was gained. An advanced analysis of the trends of inverse velocity plots was also performed to assess the potential for a slope collapse at the 10-mile Slide and to obtain further knowledge on the nature of the sliding surface.

Monitoring Surface Displacement of a Deep-Seated Landslide by a Low-Cost and near Real-Time GNSS System

“…Mainly for reasons of affordability and continuity of measurements, the use of automated GNSS receivers for such measurements is becoming increasingly common [11,43]. For monitoring small displacements, total stations, due to their high precision, still have an advantage over GNSS measurement methods [44,45]. It has been established that the coordinates from classic geodetic measurements using a total station are determined most accurately when all points are connected into a geodetic network [46,47].…”

Using Satellite Interferometry to Infer Landslide Sliding Surface Depth and Geometry

“…This means that, in general, the cross-section is not aligned E-W (as with the movement vectors); therefore, the E-W movement vectors were reprojected along the cross-section, considering that the maximum movement is expected along the steepest slope direction. It is useful to remember the first assumption made in Section 2.1, i.e., the mass will move in a direction that is parallel to the slope of the sliding surface beneath; in fact, since the horizontal movements are reprojected along the cross-section where the maximum movement is expected, if a landslide experiences radial movements (i.e., the sides of a landslide diverge from the coaxial displacement either because they spread laterally or are dragged towards the central section, such as in [46,47], respectively), when these will be reprojected along the coaxial cross-section, their horizontal component will be underestimated with respect to the vertical one.…”

Advanced analysis of satellite data reveals ground deformation precursors to the Brumadinho Tailings Dam collapse

“…Temporal prediction of the dam collapse. The timing of the failure of Dam I at Brumadinho was estimated using the well-established inverse velocity method 24,26,[39][40][41] , which involves fitting a straight line to inverse velocity values that decrease over time to zero on the approach to a slope collapse. To achieve this, the velocities at each time point were computed from the change in displacement observed between successive InSAR observations made at 12-day intervals.…”