scholarly journals Kinematic Analysis and Rock Mass Classifications for Rock Slope Failure at USAID Highways

2019 ◽  
Vol 13 (4) ◽  
pp. 379-398
Author(s):  
Ibnu Rusydy ◽  
Nafisah Al-Huda ◽  
M. Fahmi ◽  
Naufal Effendi
Keyword(s):  
Rock Mass ◽  
Kinematic Analysis ◽  
Slope Failure ◽  
Rock Slope

scholarly journals STABILITY ANALYSIS AND FAILURE MECHANISMS OF OPEN PIT ROCK SLOPE

2017 ◽  
Vol 2 (3) ◽  
pp. 255
Author(s):  
Yahdi Azzuhry
Keyword(s):  
Rock Mass ◽  
Class Number ◽  
Kinematic Analysis ◽  
Slope Failure ◽  
Rock Slope ◽  
Failure Mechanisms ◽  
Slope Angle ◽  
Open Pit ◽  
Wedge Failure ◽  
Planar Failure

Rock mass in nature tend to be unideal, for it is heterogeneous, anisotropic and has discontinuity. The discontinuity makes anisotropic strength and stress in the rock mass, and also controls the changing of the elastic properties of rock mass. This condition results to disruptions in the rock mass strength balance, and finally drives the slopes to collapse. This study aims to determine the slope failure mechanisms in the area of case study, as well as its variations based on the Rock Mass Rating (RMR), Geological Strength Index (GSI), Slope Mass Rating (SMR), kinematic analysis, numerical analysis and monitoring approach slope movement in a coal mine slope applications. The site investigations were implemented to obtain information about slope collapse. Prior to the collapse, the slope inclination was 38° with of 94 meters height, strike slope of N 245 E and direction of slope surface of 335°. After the collapse, the slope was became 25º; and after the collapse materials were cleared, it was 35º. The discontinuity mapping obtained 5 sets of discontinuities, and the data were developed to obtain the value of RMR. The result of piezometer measurements was that at occurrence of collapse, slope elevation was 44.40m. Displacement value from monitoring SSMR showed that when the slope was collapsing in two stages, the first stage value was 70.61cm (a more critical condition, the value was rounded down to 70cm to the implementation in modelling) and the second stage value was at 124.25cm. The value of RMR89 in this study was greater than the value of GSI and SMR. As for the average value, it was obtained 34.67 for RMR89 value and 29.67 for GSI value, these rocks then can be classified into Poor Rock class number IV. The result of kinematic analysis found that sliding planar failure at dips 36°, and wedge failure at dips 36°, 35° and 34°. Acquisition SMR value obtained at 25, 27, 28 and 29. The SMR values classified the rock mass quality into class number IV, the description of the rock mass was relatively poor, the slope stability was low or unstable and the collapse manifold was planar or wedge failure. The result from the analysis of the model with its criteria obtained was that un-collapse conditions at angle 29°. It is recommended to use 29° angle to repair the slopes, and also recommended for overall high wall slope angle. Type of collapse that occurred on the slope failure mechanisms in all of the analysis that has been done, it is known that the mechanisms involved are complex types (combine of wedge failure, planar failure, and step-path failure) or classified into large scale rock slope failure surface.

Twenty-ninth Canadian Geotechnical Colloquium: The role of advanced numerical methods and geotechnical field measurements in understanding complex deep-seated rock slope failure mechanisms

2008 ◽  
Vol 45 (4) ◽  
pp. 484-510 ◽  
Author(s):  
Erik Eberhardt
Keyword(s):  
Rock Mass ◽  
Numerical Modelling ◽  
Slope Failure ◽  
Rock Slope ◽  
Current Knowledge ◽  
Progressive Failure ◽  
Strength Degradation ◽  
Rock Slope Stability ◽  
Clear Understanding ◽  
Rock Mass Strength

The underlying complexity associated with deep-seated rock slope stability problems usually restricts their treatment to phenomenological studies that are largely descriptive and qualitative. Quantitative assessments, when employed, typically focus on assessing the stability state but ignore factors related to the slope’s temporal evolution including rock mass strength degradation, internal shearing, and progressive failure, all of which are key processes contributing to the final collapse of the slope. Reliance on displacement monitoring for early warning and the difficulty in interpreting the data without a clear understanding of the underlying mechanisms has led to a situation where predictions are highly variable and generally unreliable. This paper reviews current knowledge regarding prefailure mechanisms of massive rock slopes and current practices used to assess the hazard posed. Advanced numerical modelling results are presented that focus on the importance of stress- and strain-controlled rock mass strength degradation leading to failure initiation. Efforts to address issues related to parameter and model uncertainty are discussed in the context of a high alpine research facility, the “Randa In Situ Rockslide Laboratory”, where state-of-the-art instrumentation systems and numerical modelling are being used to better understand the mechanisms controlling prefailure deformations over time and their evolution leading to catastrophic failure.

scholarly journals Stability and sustainability assessment for the surface failure of various rock slopes excavated along the Konya-Alanya Road segment, Turkey

2021 ◽  
Vol 48 (4) ◽  
Author(s):  
Ali F. BAYRAM ◽  
◽  
Ahmed I. MOHAMED ◽  
Arsalan A. OTHMAN ◽  
◽  
...  
Keyword(s):  
Rock Mass ◽  
Kinematic Analysis ◽  
Slope Failure ◽  
Sustainability Assessment ◽  
Slope Instability ◽  
Laboratory Measurements ◽  
The Road ◽  
Hilly Region ◽  
Pass Through ◽  
The Stability

Most of the road networks in Turkey pass through the Hilly region. These roads are constructed through inadequate blasting accompanied by road deterioration or collapse. To date, several researchers in Turkey have not paid adequate attention to the stability analysis of road failures based on the surface orientation of the dominant discontinuity sets. This study, based on the field survey, laboratory measurements, and the use of Dips analyst software, aims to investigate the stability and sustainability of seven different sites that exhibit imminent slope failure along the Konya-Alanya Road (KAR) segment. The sites selected are geologically investigated and geotechnically evaluated using a scan-line survey. We carried out several fields and laboratory measurements. Both Slope Mass Rating (SMR) and Rock Mass Rating (RMR) are quantified and included with rock mass assessment of each slope site. Both the field and laboratory results are integrated by kinematic analysis methods to assess the potential failure of these slopes. The kinematic analysis results demonstrate that the dominant failure forms are planar, wedge, and toppling. RMRb results show that some slopes with good rock quality remain unstable and vulnerable to failure despite their fair RMRb values. While SMR results show that five of the seven sites are risky, thus, described as partly stable, and the other two are unstable. The results have also implications for the understanding of the causal factors for slope instability, include the discontinuities present in the rock mass, physical, environmental, and meteorological factors influencing them. This study concludes that urgent remedial measures for their long-term stability are recommended.

scholarly journals Seismic Analysis of a Limestone Rock Slope Through Numerical Modelling: Pseudo-Static vs. Non-Linear Dynamic Approach

2021 ◽  
Vol 906 (1) ◽  
pp. 012093
Author(s):  
Alberto Bolla ◽  
Paolo Paronuzzi
Keyword(s):  
Rock Mass ◽  
Stability Condition ◽  
Slope Failure ◽  
Rock Slope ◽  
Seismic Analysis ◽  
Dynamic Approach ◽  
Linear Dynamic ◽  
Non Linear ◽  
Static Approach ◽  
Limestone Rock

Abstract In the present work, a seismic analysis was performed in advance on a limestone rock slope (height = 150 m) outcropping along the Tagliamento River valley, in the Friuli Venezia Giulia Region, north-eastern Italy. The analysed slope is characterised by strong rock mass damage, thus resulting in a critical stability condition (unstable volume = 110,000–200,000 m3). The seismic analysis was performed adopting the 2D finite difference method (FDM) and employing both a pseudo-static approach and a non-linear dynamic approach. Model outcomes demonstrate that the seismic motion induces internal, localised ruptures within the rock mass. Some important differences in the mechanical behaviour of the rock slope were highlighted, depending on the specific modelling approach assumed. When adopting a pseudo-static approach, the slope failure occurs for PGA values ranging between 0.056 g and 0.124 g, depending on the different initial static stability condition assumed for the slope (Strength Reduction Factor SRF = 1.00–1.15). According to the non-linear dynamic approach, the slope failure is achieved for PGA values varying between 0.056 g and 0.213 g. Pre-collapse slope displacements calculated with the pseudo-static approach (12–15 cm) are much more greater than those obtained through the non-linear dynamic approach (0.5–3 mm). The modelling results obtained through the non-linear dynamic analysis also testify that the seismic topographic amplification is 1.5 times the target acceleration at the slope face and 2.5 times the target acceleration at the slope toe.

Rockfall Analysis of State Highway along the Southern Vicinity of Aizawl, Mizoram

2021 ◽  
Vol 9 (2) ◽  
pp. 100-112
Author(s):  
Zairem mawii ◽  
◽  
H. Lalhlimpuia ◽  
Lalhming sangi ◽  
V. Vanthangliana ◽  
...  
Keyword(s):  
Rock Mass ◽  
Kinematic Analysis ◽  
Slope Failure ◽  
Monsoon Season ◽  
Poor Quality ◽  
High Rate ◽  
Actual Condition ◽  
Common Phenomenon ◽  
State Highway ◽  
The Government

Slope failure in the form of rockfall is a common phenomenon that occur in the hilly ranges of Himalayas. Mizoram, being a part of it experiences a high rate of rockfall throughout the year especially during the monsoon season. This paper focus on frequent rock fall along the State highway between Aizawl to Lunglei via Thenzawl at Midumkham, Sumsuih village. Damage of passenger vehicles, public goods carrier trucks, private vehicles and road blocks are the common phenomenon due to various forms of landslide within the study area. The death of a couple on 14th October 2016 due to rockfall within the study area captivate attention of government as well as the local about the condition of the area. Thus, detailed study of the area becomes mandatory so as to reduce rockfall and to educate the government and locals about the actual condition of the area. Field reconnaissance has been carried out to collect joint data for kinematic analysis. The behaviour of rockfall was determined by kinematic analysis using Rocscience software Dips 6.0, the stereograph shows that toppling, planar and wedge type are the potential modes of failures. The rock beddings are classified based on RMR (Rock Mass Rating) and SMR (Slope Mass Rating). About 90% of the selected site shows that low RMR as well as SMR value. The RMR values of the rock exposed in the study area indicated a very poor quality of rock mass. The average stand up time obtained 30 min for 1m span suggest high rate of erosion of rocks in the area. The rock slopes represent Class V of Romana classification, considered as very bad rock mass and completely unstable. The low value of rebound number and strength of the rock along with presence of numerous joints determined the high vulnerability of the study area

scholarly journals A temperature- and stress-controlled failure criterion for ice-filled permafrost rock joints

2018 ◽  
Vol 12 (10) ◽  
pp. 3333-3353 ◽  
Author(s):  
Philipp Mamot ◽  
Samuel Weber ◽  
Tanja Schröder ◽  
Michael Krautblatter
Keyword(s):  
Normal Stress ◽  
Failure Criterion ◽  
Slope Failure ◽  
Rock Slope ◽  
Shear Resistance ◽  
Stress Conditions ◽  
Rock Joints ◽  
Normal Stresses ◽  
Permafrost Rock ◽  
Limestone Sample

Abstract. Instability and failure of high mountain rock slopes have significantly increased since the 1990s coincident with climatic warming and are expected to rise further. Most of the observed failures in permafrost-affected rock walls are likely triggered by the mechanical destabilisation of warming bedrock permafrost including ice-filled joints. The failure of ice-filled rock joints has only been observed in a small number of experiments, often using concrete as a rock analogue. Here, we present a systematic study of the brittle shear failure of ice and rock–ice interfaces, simulating the accelerating phase of rock slope failure. For this, we performed 141 shearing experiments with rock–ice–rock “sandwich”' samples at constant strain rates (10−3 s−1) provoking ice fracturing, under normal stress conditions ranging from 100 to 800 kPa, representing 4–30 m of rock overburden, and at temperatures from −10 to −0.5 ∘C, typical for recent observed rock slope failures in alpine permafrost. To create close to natural but reproducible conditions, limestone sample surfaces were ground to international rock mechanical standard roughness. Acoustic emission (AE) was successfully applied to describe the fracturing behaviour, anticipating rock–ice failure as all failures are predated by an AE hit increase with peaks immediately prior to failure. We demonstrate that both the warming and unloading (i.e. reduced overburden) of ice-filled rock joints lead to a significant drop in shear resistance. With a temperature increase from −10 to −0.5 ∘C, the shear stress at failure reduces by 64 %–78 % for normal stresses of 100–400 kPa. At a given temperature, the shear resistance of rock–ice interfaces decreases with decreasing normal stress. This can lead to a self-enforced rock slope failure propagation: as soon as a first slab has detached, further slabs become unstable through progressive thermal propagation and possibly even faster by unloading. Here, we introduce a new Mohr–Coulomb failure criterion for ice-filled rock joints that is valid for joint surfaces, which we assume similar for all rock types, and which applies to temperatures from −8 to −0.5 ∘C and normal stresses from 100 to 400 kPa. It contains temperature-dependent friction and cohesion, which decrease by 12 % ∘C−1 and 10 % ∘C−1 respectively due to warming and it applies to temperature and stress conditions of more than 90 % of the recently documented accelerating failure phases in permafrost rock walls.

scholarly journals Assessment of Slope Instability and Risk Analysis of Road Cut Slopes in Lashotor Pass, Iran

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Mohammad Hossein Taherynia ◽  
Mojtaba Mohammadi ◽  
Rasoul Ajalloeian
Keyword(s):  
Rock Mass ◽  
Risk Analysis ◽  
Rock Slope ◽  
Classification Systems ◽  
Slope Instability ◽  
Rock Slope Stability ◽  
Rock Slopes ◽  
The Stability ◽  
Cut Slopes ◽  
Road Cut Slopes

Assessment of the stability of natural and artificial rock slopes is an important topic in the rock mechanics sciences. One of the most widely used methods for this purpose is the classification of the slope rock mass. In the recent decades, several rock slope classification systems are presented by many researchers. Each one of these rock mass classification systems uses different parameters and rating systems. These differences are due to the diversity of affecting parameters and the degree of influence on the rock slope stability. Another important point in rock slope stability is appraisal hazard and risk analysis. In the risk analysis, the degree of danger of rock slope instability is determined. The Lashotor pass is located in the Shiraz-Isfahan highway in Iran. Field surveys indicate that there are high potentialities of instability in the road cut slopes of the Lashotor pass. In the current paper, the stability of the rock slopes in the Lashotor pass is studied comprehensively with different classification methods. For risk analyses, we estimated dangerous area by use of the RocFall software. Furthermore, the dangers of falling rocks for the vehicles passing the Lashotor pass are estimated according to rockfall hazard rating system.

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