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This paper deals with the analysis of scan line survey data gathered from three selected slope sites situated along Kattas-Choa Saiden Shah road in Pakistan. The road side slope sites around Kattas-Choa Saiden Shah road can be vulnerable to mass movement processes, most commonly due to rock fall/sliding. These consist of Potwar portion (the Sakesar...
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... In the meantime, the measured intersection line was dipping at an angle less than that of the slope face, moreover, the intersection lines were dipping at an angle greater than that of the friction of the discontinuities. The above-mentioned characteristics of the slope have been well established to generate unstable wedges across the slope (Ali et al., 2015;West and Cho, 2007). ...
... Lastly, the lateral extent of the potential failure mass was isolated by lateral release surfaces which free a block for sliding. The above-mentioned measures correlate very well with some of the conclusions drawn by Ali et al. (2015), West and Cho (2007), and Wyllie and Mah (2004) concerning governing factors that influence the occurrence of this failure. Concerning Fig. 11b, the planar failure mode of the road slopes is denoted with several loose rocks shown across the slope. ...
Advanced reliability analysis of road-slope stability in a brittle and faulted rockmass terrain by several techniques is described in this paper. The proposed analysis integrates several classical methods for the analysis of slope stability. The methods include remote sensing technique together with kinematic analysis, Finite Element Method (FEM), and Finite Difference Method (FDM). The Sentinel-2B imaging techniques have classified most of the slopes as high susceptibility, most of these slopes have been observed to consist of active rockfalls. Furthermore, circular, toppling, planar, and wedges failures were denoted to be the most kinematic failures associated with the slopes. However, wedge failure was more pronounced than other kinematic failures. On the other hand, simulation of FoS and maximum displacement of the slope was conducted using FLACSlope. The simulation confirmed that the composition of the slopes contributes greatly to its FoS and rockmass displacement. Indeed, a slope with one rock unit was simulated to be stable with less rockmass displacement, however in a case of brittle and faulted rockmass the FoS was very low with extensive displacement simulated across the slope. The later simulation corresponds with the conditions of the current study. Finally, the influence of geological features was studied with varying stages of road construction. The simulations have shown a rapid increase in rockmass displacement generated by the joints as the stages of road construction progress. It appears that the brittleness, faulting, slope properties, and unsupported rockmass are the most contributing factors toward slope instability.
... (e.g. Varnez 1981;Granger 1998;Aleotti and Chowdhury 1999;Ali et al. 2015). Although the knowledge regarding stability analyses and monitoring the slope movements and stabilization techniques improved substantially in recent years, rock slope instability still imposes heavy social, economic, and environmental tolls in mountainous areas. ...
Interest in rock slope stability in mountainous regions has increased greatly in recent years. This issue has become a topic of major interest for geoscientists and engineering professionals, as well as for private citizens and local administrators, in many parts of the world. This paper evaluates the stability of seven rock slopes along the Kamyaran-Marivan tourist road, Kurdistan province, Iran, using various methods. The two main reasons for performing this research were to determine whether different methods of stability analysis provide the same results, and to determine how different factors such as the presence of water, tension cracks, and seismic forces affect the stability of these rock slopes. Firstly, field investigations were performed to obtain the engineering characteristics of the rock masses, discontinuities, and intact rocks of the slopes. Secondly, laboratory tests were carried out on rock samples obtained from the slopes, to determine the engineering properties of the intact rocks. Then for each rock slope, the contour diagram of discontinuities and slope face was drawn in the Dips v.5.1 software environment, and the failure mechanism was determined based on the kinematic or stereographic method. Next, the factors of safety of the rock slopes were calculated using the limit equilibrium method, based on the failure mechanisms resulting from the kinematic method. The accuracy of the results obtained by these two methods was investigated using SWedge v.4.0 software. The results indicated that four rock slopes have a potential for plane, wedge, and toppling failure, and three others are stable. Also, it was found that the stability of the studied rock slopes decreases greatly in the presence of water, tension cracks, and seismic forces.
... The permissible limits for factors 'a f ', 'a p ' and 'u' were defined with respect to the kinematic condition; a f > a p > u. It implies that for plane failure 'a f ' must be greater than 'a p ' while in turn it should be greater than 'u' (Raghuvanshi, 2019;Ali et al., 2015;Hoek and Bray, 1981;Markland, 1972;Hocking, 1976). Thus, the value for 'a p ' for each slope section under study was varied in between 'a f ' and 'u' values. ...
The present study was carried out to understand the relative influence of governing factors on slopes having potential plane mode of failure. For the present study secondary data for seventeen slope sections having potential plane mode of failure was procured from varied geological and geographical environment. The governing factors that were considered for statistical analysis are; slope-angle (αf), upper-slope angle (αs), dip of potential failure plane (αp), dip of tension-crack (αt), slope-height (h), cohesion (C), angle of friction (φ) and height of the water in tension-crack (Zw). Initially, factor of safety (FoS) was determined for all possible anticipated adverse conditions to which slopes may be subjected. Later, sensitivity analysis was undertaken to know the relative importance of the governing factors on FoS. Further, one-way Analysis-of-Variance (ANOVA) was applied to examine the statistical significance of these governing factors on FoS under static and dynamic conditions. The results clearly showed that all the slope sections are unstable when saturated under static and dynamic conditions. Further, statistical analysis results showed that all considered governing factors are statistically significant for slope stability assessment however; their relative importance varies from one slope type to another. In terms of order of importance, factors ‘αp’ ‘Zw’ ‘αf’ and ‘h’ revealed as the most significant factors while factors ‘αt’ ‘φ’ ‘αs’ and ‘C’ though significant but are relatively lower in the order of importance. The relative order of importance deduced from sensitivity analysis may be helpful in decision making to workout optimum stabilization measure for a particular slope.
... The zone demarcated by the friction circle and the slope face is designated as sliding envelope (Fig.6). If any great circle of a discontinuity plane, having strike nearly parallel to the slope face, falls within this sliding envelope, kinematic condition is satisfied (Ali et al., 2015). ...
In stratified sedimentary and meta-sedimentary rock formations ‘plane mode’ of rock failure is very common. The plane failure occurs when a structural discontinuity plane such as; bedding plane, fault plane or preferred orientations of a joint set dips or daylight towards the valley or excavation at an angle smaller than the slope angle and greater than the angle of friction of the discontinuity surface. The stability of the slope, having plane mode of failure, depends on the geometry, rock type, potential failure plane characteristics, groundwater conditions, dynamic loading and the surcharge conditions. The slope may demonstrate these conditions in a simple uniform manner or there may be complex conditions owing to variability in the slope geometry and heterogeneity in the slope material. The stability of the slope, having plane mode of failure, can be assessed by different methods which can be broadly classified as conventional and numerical methods. Conventional methods include; kinematic methods, empirical methods, limit equilibrium and probabilistic methods, whereas numerical methods include continuum, discontinuum and hybrid methods. Each of these methods has their own advantage and limitations owing to the slope conditions, application requirement and capability of an expert. In this paper a comprehensive review on governing parameters and various stability analysis techniques for plane mode of failure in rock slopes is presented.
The research aimed to study 24 rock slope surfaces along the road around Hon Lon Island, Kien Hai district, Kien Giang province, Vietnam. The analytical results have determined slope failure, wedge failure, and toppling, which occurred on almost slope surface and the average percentage of plane failure is the largest. The average percent of plane failure is 19.23%, the wedge failure is 15.35%, and the toppling fault is 6.73%. Besides, the analytical results have also identified the slope surfaces which can be the key blocks: ND-13, 18, 23, 25, 34, 37, 45, 51, 62, 63. The other analytical results show that the existence of key blocks at the rock slope surfaces in the N-S direction, dip to E at the survey locations: ND-13, 23, 63 and dip to W at the survey locations: ND-37, 45; in the NE-SW direction, dip to SE at the survey locations: ND-15, 62 and dip to NW at the survey locations: ND-18, 34; in the NW-SE direction, dip to SW at the survey location ND-51. These results have important significance to support for protecting slope surface safety.
The main goal of this research was to perform a landslide hazard zonation and evaluation around Debre Markos town, North West Ethiopia, found about 300 km from the capital city Addis Ababa. To achieve the aim, a GIS-based probabilistic statistical technique was used to rate the governing factors, followed by geoprocessing in the GIS setting to produce the landslide hazard zonation map. In this research, eight internal causative and external triggering factors were selected: slope material (lithology and soil mass), elevation, aspect, slope, land use land cover, curvature, distance to fault, and distance to drainage. Data were collected from field mapping, secondary maps, and digital elevation models. Systematic and detailed fieldwork had been done for image interpretation and inventory mapping. Accordingly, the past landslides map of the research area was prepared. All influencing factors were statistically analyzed to determine their relationship to previous landslides.
The results revealed that 17.15% (40.60 km2), 25.53% (60.45 km2), 28.04% (66.39 km2), 18.93% (44.83 km2), and 10.36% (24.54 km2) of the research area falls under no hazard, low hazard, moderate hazard, high hazard, and very high hazard respectively. The validation of the landslide hazard zonation map reveals that 1%, 2%, 3%, and 94% of past landslides fall in no hazard zone, low hazard, moderate hazard zone, and high hazard or very high hazard zones respectively. The validation of the landslide hazard zonation map thus, it has been adequately demonstrated that the adopted approach has produced acceptable results. The defined hazard zones can practically be utilized for land management and infrastructure construction in the study area.
This research was conducted in an area around AlemKetema, North Showa, central Ethiopia; with a general objective of conducting a rock slope stability assessment on the selected natural rock slope sections. To achieve this objective, slope stability probability classification was followed to determine the stability probability conditions of slope rock mass in the study area. These classification systems mainly depend on the primary data collected from field works. As a reason, systematic and extensive fieldwork was conducted. However, secondary data was also required to characterize the general conditions of the study area and to have a deep understanding of the subject matter. In the SSPC system, ratings for the degree of weathering, intact rock strength, method of excavation, roughness condition, and infill material were given according to standards. The slope stability probability classification (SSPC) system practices three-step classification systems. These steps are exposure rock mass, reference rock mass, and slope rock mass. Following these steps, slope rock mass stability probability classifications have been carried out for 92 natural rock slope sections. The stability of slope rock mass was determined by two different approaches namely orientation-dependent and orientation independent stability. Orientation dependent stability is linked with the orientation of the discontinuities and characterized by toppling and sliding criteria, while orientation independent stability is linked with the strength of slope rock mass. Accordingly, the overall assessment indicated that 80.4% of rock slope sections showed less than 5% stability probability, 10.9% of rock slope sections showed from 5 to 49%, 6.5% showed from 50 to 95%, and the rest 2.2% of rock slope sections showed greater than 95% stability probability. All these results were compared with the visual stability assessment results. Accordingly, different stability probability maps were produced.
