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The paper describes the recent devastating landslide of Kotrupi, Himachal Pradesh in India which had claimed many human lives and properties along its course on 13 August 2017. This event was the third reactivation of the slide as per data available. The study for this landslide involves a preliminary investigation of the site and comparison of pre- and post-event slope stability analysis. Other than rainfall, the combined effect of differential weathering rate of the debris and soil layers, low material strength, and the presence of a fault zone was found to be the primary cause of instability. The analysis was carried out with the geotechnical investigation and numerical modeling with the help of finite element model-based Phase 2 simulator. The significant findings of this paper include numerical simulation of pre- and post-event slide as stated under unsaturated and saturated condition. The study finds a low factor of safety of the present slope. The unstable condition of the slope may trigger another event of the same intensity shortly. [ABSTRACT FROM AUTHOR]

Detailed surface topography is important when analyzing the stability of slopes. Recent advances in new technologies such as interferometric synthetic aperture radar and light detection and ranging have allowed us to obtain high-precision profiles of distant landscapes and objects including detailed slope information for three-dimensional (3D) slope stability analysis. However, techniques of reconstructing 3D numerical models from scanned data of slope geometry have not been well investigated or tested. This paper proposes a comprehensive approach that integrates laser scanning and finite element method for slope stability analysis, particularly failure prediction under precipitation scenarios. The methodology is applied to a slope in the Wenchuan earthquake-stricken mountainous region that failed in 2013, triggered by severe rainfall. The modelling results show that the surface sampling resolution can affect the prediction accuracy of the potential failure zones. When constructing the slope model, the selected surface grid should be fine enough to capture the important topographic features of the slope while minimizing computation demand. This paper confirms that the proposed method can be successfully used to identify the potential failure zones of the investigated slope under severe rainfall conditions. [ABSTRACT FROM AUTHOR]

Abstract: Discontinuous deformation analysis (DDA) has been widely applied in simulations of discontinuous blocky systems. The behavior of a discontinuous blocky system is mainly governed by the strength of the interface joints. The Mohr–Coulomb joint failure criterion, adopted in the original DDA, is examined through a classic case of a single block on an inclined plane. It shows that when interface cohesion exists, the block may be unstable even if the interface strength is greater than the theoretical strength required for critical stability, as the cohesion has been improperly removed. Adopting relative displacement between contacted blocks as the criterion for the removal of cohesion will provide more accurate results. The development of DDA with displacement-dependent interface shear strength is presented in this paper. To implement and illustrate the modified algorithm, two examples of progressive landslide failure simulations are performed. Both systems exhibit a two-stage failure pattern: a relatively slow, downward progressive failure stage followed by a rapid, massive run out failure stage. [Copyright &y& Elsevier]