Simulation of fragmental rockfalls detected using terrestrial laser scans from rock slopes in south-central British Columbia, Canada

Abstract

Abstract. Rockfall presents an ongoing challenge to the safe operation of transportation infrastructure, creating hazardous conditions which can result in damage to roads and railways, as well as loss of life. Rockfall risk assessment frameworks often involve the determination of rockfall runout in an attempt to understand the likelihood that rockfall debris will reach an element at risk. Rockfall modelling programs which simulate the trajectory of rockfall material are one method commonly used to assess potential runout. This study aims to demonstrate the effectiveness of a rockfall simulation prototype which uses the Unity 3D game engine. The technique is capable of simulating rockfall events comprised of many mobile fragments, a limitation of many industry standard rockfall modelling programs. Five fragmental rockfalls were simulated using the technique, with slope and rockfall geometries constructed from high-resolution terrestrial laser scans. Simulated change detection was produced for each of the events and compared to the actual change detection results for each rockfall as a basis for testing model performance. In each case the simulated change detection results aligned well with the actual observed change in terms of location and magnitude. An example of how the technique could be used to support the design of rockfall catchment ditches is shown. Suggestions are made for future development of the simulation technique with a focus on better informing simulated rockfall fragment size and the timing of fragmentation.

The Implications of M3C2 Projection Diameter on 3D Semi-Automated Rockfall Extraction from Sequential Terrestrial Laser Scanning Point Clouds

“…The M3C2 algorithm operates directly on the point clouds, and therefore requires no meshing or gridding, which can induce geometry errors in the terrain model as noted earlier. As a result, M3C2 has become a widely used and preferred method for change detection in various fields, including the monitoring of rock slopes and cliffs with TLS [13,14,[24][25][26]29,39], landslide deformation [27], retrogressive thaw slump monitoring [32], rockfall model calibration [22], archaeological monitoring and preservation [40,41], structure from motion (SfM) photogrammetry monitoring and error analysis [42][43][44], and various other monitoring applications in the geosciences [35,[45][46][47]. The M3C2 method is also widely used because it is freely available as a plugin within the open-source software CloudCompare [48].…”

“…The shape of a rockfall is known to have a significant effect on its passage down the slope and its runout [18,19]. Detailed 3D rockfall shape has been carried forward into a new generation of rockfall models, which have incorporated custom rockfall objects and detailed terrain models [20][21][22].…”

“…The shape of a rockfall can provide insight into the structure of the sourcing rock and the failure mechanics. With a new generation of 3D rockfall modeling software, the shape of a rockfall and the quality of the rock can also give insight into its chaotic interaction with terrain and the potential runout of the fragment(s) [20][21][22]. Blott and Pye [68] described shape using four important characteristics; form, roundness, irregularity, and sphericity.…”

Combining Ground Based Remote Sensing Tools for Rockfalls Assessment and Monitoring: The Poggio Baldi Landslide Natural Laboratory

“…As showed in Figure 9 , major rockfalls might be preceded by precursory movements (i.e., pre-failure deformation) highlighting the proneness of certain rock slopes to have deforming areas and associated opening fractures that precede the main failure event [ 111 , 112 ]. Gigapixel techniques can also be combined with LiDAR products for further analysis aimed at three-dimensional characterisation and monitoring of rock slopes [ 113 , 114 , 115 , 116 , 117 ]. In [ 62 , 115 ] the Gigapixel images have been used to identify unweathered rock surfaces in order to map recent rockfall source zones.…”

Timing, volume and precursory indicators of rock‐ and cliff fall on a permafrost mountain ridge (Mattertal, Switzerland)

“…Combining different techniques is therefore highly advantageous for detailed rockfall characterization (Dietze et al, 2017a;Fischer et al, 2011). While post-event remote sensing is common to study rockfall in the periglacial high mountain environment (Dietze et al, 2017a;Fischer et al, 2011;Le Roy et al, 2019;Sala et al, 2019), it is rare to have direct observations before, during and after rockfall events. However, it's very beneficial to have data from initial destabilization up to failure of a rock wall, because this information is of high importance for adopting early warning systems (Leinauer et al, 2020).…”