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

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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Assessment of a Modified Rock Mass Classification System for Rock Slope Stability Analysis in the Q-system

Earth Sciences Research Journal ◽

10.15446/esrj.v19n2.49127 ◽

2015 ◽

Vol 19 (2) ◽

pp. 147-152 ◽

Cited By ~ 6

Author(s):

Davood Fereidooni ◽

Gholam Reza Khanlari ◽

Mojtaba Heidari

Keyword(s):

Rock Mass ◽

Slope Stability ◽

Classification System ◽

Rock Slope ◽

Rock Mass Classification ◽

Classification Systems ◽

Rock Slope Stability ◽

Rock Slopes ◽

El Sistema ◽

Mass Classification

This paper explores the applicability of a modified Q classification system and its component parameters for analysis and conclusion of site investigation data to estimate rock slope stability. Based on the literature, Q classification system has high applicable potential for evaluation of rock mass quality. Therefore, in this study, it was used with RMR and SMR rock mass classification systems to assess stability or instability of different rock slopes along the Hamedan-Ganjnameh-Tuyserkan road, Hamedan province west of Iran. Furthermore, a modified rock mass classification system namely Slope Quality Rating (SQR) was proposed based on the correction of the Q classification parameters and calculating some new parameters such as dip and strike of discontinuities and the method of rock excavation or blasting. For this purpose, the SMR and RMR rock mass classifications were also needed. By measuring SQR for different rock slopes, it will be possible to measure Slope Mass Rating (SMR). Evaluación del sistema Q modificado de clasificación del macizo rocoso para el análisis de estabilidad de pendiente de roca ResumenEste artículo explora la aplicabilidad del sistema de clasificación Q modificado y sus parámetros para analizar y determinar la información estimada de estabilidad de pendiente de roca en el sitio determinado de estudio. Según la literatura, el sistema de clasificación Q tiene un alto potencial de aplicabilidad paral a evaluación de la calidad del macizo rocoso. En este estudio además se utilizó el sistema Q junto con los sistemas Índice de Masa de Pendiente (SMR) y Clasificación Geomecánica de Bienawski (RMR) para evaluar la estabilidad e inestabilidad de diferentes pendientes rocosas en la carretera Hamedan-Ganjnameh-Tuyserkan, de la provincia de Hamedan, en el Oeste de Irán. Además, se propone el Índice de Calidad de Pendiente (SQR), un sistema de clasificación de macizo rocoso modificado, a partir de la corrección de los parámetros de clasificación Q y el cálculo de nuevos parámetros como pendiente y caída de las discontinuidades y el método de excavación o explosión de la roca. Para esta propuesta también se utilizaron las clasificaciones SMR y RMR. La medición SQR en diferentes pendientes hizo posible el cálculo del sistema SMR.

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Influences of Joint Persistence and Groundwater on Wedge Failure Potential of Jointed Rock Slope

10.5194/egusphere-egu2020-7303 ◽

2020 ◽

Author(s):

Yu-Hsuan Chang ◽

Cheng-Han Lin ◽

Ming-Lang Lin

Keyword(s):

Rock Slope ◽

Water Pressure ◽

Jointed Rock ◽

Slope Instability ◽

Rock Slope Stability ◽

Rock Slopes ◽

Wedge Failure ◽

Large Landslide ◽

Potential Failure ◽

The Stability

Joint persistence and groundwater are critical factors that influence the stability of rock slope. Persistence dominates the extent of pre-existing potential failure surfaces. Under certain conditions, slope instability may vary with time, as the propagation of existing joints leads to the development of fully persistence failure surfaces. At the same time, groundwater may travel through the fracture network and provides an external force to unstable rock masses, resulting in the damage of rock slope failure hard to predict. In general, when a rock slope consists of two or more sets of joints, the wedge failure often becomes the initial structurally controlled failure of a progressive large landslide. A classic case, which was occurred at a steep cut rock slope on 32.5k, Provincial Highway 7, Taiwan, had been completely recorded with UAV-surveys, field investigations and witness. The landslide first occurred on 13th May 2019 as a wedge failure with the magnitude of the volume of 892 m3 and resulted in a large landslide on 29th July 2019 with the magnitude of the volume of 37234 m3, destroyed the protection measures and roads. According to the field investigation, groundwater was discovered flowing out from the line of intersection of persistence joints, which could be the main reason leads to the wedge failure and the progressive large rockslide. Hence, the couple mechanics-hydraulic behavior in a rock slope should be studied in more detail to mitigate such hazards.In this study, sandbox model was applied to clarify the effects of the groundwater and joint friction on failures of single rock wedge. In addition, the software 3DEC, which is based on Distinct Element method, was carried out to extent the analysis conditions. The results of sandbox simulations were used to calibrate the performance of the numerical model, especially the coupled hydro-mechanical analysis. The stability of jointed rock slopes under different persistence and various water pressure conditions has been studied. It is believed that the study can enhance the way for stability analysis and monitoring of the potential failure of jointed rock slopes.Keywords: Wedge failure; Joint persistence; Groundwater; Rock slope stability.&#160;

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Stability assessment of degrading permafrost rock slopes based on a coupled thermo-mechanical model

10.5194/esurf-2020-70 ◽

2020 ◽

Author(s):

Philipp Mamot ◽

Samuel Weber ◽

Saskia Eppinger, ◽

Michael Krautblatter

Keyword(s):

Slope Stability ◽

Rock Slope ◽

Fracture Network ◽

Slope Instability ◽

Rock Slope Stability ◽

Permafrost Degradation ◽

Rock Slopes ◽

High Mountains ◽

Permafrost Rock ◽

Wide Range

Abstract. In the last two decades, permafrost degradation has been observed to be a major driver of enhanced rock slope instability and associated hazards in high mountains. While the thermal regime of permafrost degradation in high mountains has already been intensively investigated, the mechanical consequences on rock slope stability have so far not been reproduced in numerical models. Laboratory studies and conceptual models argue that warming and thawing decrease rock and discontinuity strength and promote deformation. This study presents the first general approach for a temperature-dependent numerical stability model that simulates the mechanical response of a warming and thawing permafrost rock slope. The proposed procedure is applied to a rockslide at the permafrost-affected Zugspitze summit crest. Laboratory tests on frozen and unfrozen rock joint and intact rock properties provide material parameters for the discontinuum model developed with the Universal Distinct Element Code (UDEC). Geophysical and geotechnical field surveys deliver information on the permafrost distribution and fracture network. The model demonstrates that warming decreases rock slope stability to a critical level, while thawing initiates failure. A sensitivity analysis of the model with a simplified geometry and warming trajectory below 0 °C shows that progressive warming close to the melting point initiates instability above a critical slope angle of 50–62°, depending on the orientation of the fracture network. The increase in displacements intensifies for warming steps closer to zero degree. The simplified and generalised model can be applied to permafrost rock slopes (i) which warm above −4 °C, (ii), with ice-filled joints, (iii) with fractured limestone or probably most of the rock types relevant for permafrost rock slope failure, (iv) with a wide range of slope angles (30–70°) and orientations of the fracture network (consisting of three joint sets). The presented model is the first one capable of assessing the future destabilisation of degrading permafrost rock slopes.

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AN EVALUATION OF ROCK SLOPE STABILITY USING LIMIT EQUILIBRIUM ANALYSES

Journal of Applied Geology ◽

10.22146/jag.7220 ◽

2015 ◽

Vol 6 (2) ◽

Author(s):

Faridha Aprilia ◽

I Gde Budi Indrawan

Keyword(s):

Slope Stability ◽

Rock Slope ◽

Limit Equilibrium ◽

Rock Slope Stability ◽

Rock Slopes ◽

Plane Failure ◽

General Limit ◽

The Stability ◽

Equilibrium Analyses ◽

Limit Equilibrium Analyses

The stability of rock slopes is controlled by several factors, such as the intact rock strength, discontinuity characteristics, groundwater condition, and slope geometry. Limit equilibrium (LE) analyses have been commonly used in geotechnical practice to evaluate the stability of rock slopes. A number of methods of LE analyses, ranging from simple to sophisticated methods, have been developed. This paper presents stability analyses of rock slopes at the Batu Hijau open mine in Sumbawa Barat using various methods of LE analyses. The LE analyses were conducted at three cross sections of the northern wall of the open mine using the Bishop Simplified, Janbu Simplified, Janbu Generalised, and General Limit Equilibrium (GLE) methods in Slide slope stability package. In addition, a Plane Failure (PF) analysis was performed manually. Shear strength data of the discontinuity planes used in the LE analyses were obtained from back analyses of previous rock slope failures. The LE analysis results showed that the rock slopes were likely to have shallow non-circular critical failure surfaces. The factor of safety (Fs) values obtained from the Bishop Simplified, Janbu Simplified, Janbu Generalised, and GLE methods were found to be similar, while the Fs values obtained from the PF method were higher than those obtained from the more rigorous methods. Keywords: Batu Hijau mine, Bishop Simplified, Janbu Simplified, Janbu Generalised, limit equilibrium analyses, general limit equilibrium, rock slope stability, plane failure.

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Stability Assessment of the Excavated Rock Slope at the Dagangshan Hydropower Station in China Based on Microseismic Monitoring

Advances in Civil Engineering ◽

10.1155/2018/4567258 ◽

2018 ◽

Vol 2018 ◽

pp. 1-16 ◽

Cited By ~ 2

Author(s):

K. Ma ◽

N. W. Xu ◽

Z. Z. Liang

Keyword(s):

Rock Mass ◽

Slope Stability ◽

Monitoring System ◽

Rock Slope ◽

Rock Slope Stability ◽

Hydropower Station ◽

Bank Slope ◽

The Stability ◽

The Right ◽

Dagangshan Hydropower Station

A high-resolution microseismic (MS) monitoring system was implemented at the right bank slope of the Dagangshan hydropower station in May 2010 to analyse the slope stability subjected to continuous excavation. The MS monitoring system could real-time capture a large number of seismic events occurring inside the rock slope. The identification and delineation of rock mass damage subject to excavation and consolidation grouting can be conducted based on the analysis of tempospatial distribution of MS events. However, how to qualitatively evaluate the stability of the rock slope by utilizing these MS data remains challenging. A damage model based on MS data was proposed to analyse the rock mass damage, and a 3D finite element method model of the rock slope was also established. The deteriorated mechanical parameters of rock mass were determined according to the model elements considering the effect of MS damage. With this method, we can explore the effect of MS activities, which are caused by rock mass damage subjected to excavation and strength degradation to the dynamic instability of the slope. When the MS damage effect was taken into account, the safety factor of the rock slope was reduced by 0.18 compared to the original rock slope model without considering the effect. The simulated results show that MS activities, which are subjected to excavation unloading, have only a limited effect on the stability of the right bank slope. The proposed method is proven to be a better approach for the dynamical assessment of rock slope stability and will provide valuable references for other similar rock slopes.

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Stability Analysis of Rock Slope Based on Preferred Structural Plane

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.243-249.2254 ◽

2011 ◽

Vol 243-249 ◽

pp. 2254-2258 ◽

Cited By ~ 1

Author(s):

Wen Zhong ◽

Zhuo Ying Tan ◽

Lan Qiao

Keyword(s):

Rock Mass ◽

Stability Analysis ◽

Rock Slope ◽

Stereographic Projection ◽

Rock Slope Stability ◽

Combined Method ◽

Structural Plane ◽

Stability Of Slope ◽

The Stability ◽

Stability Of Rock Slope

Aimed at stability of rock slope, the attitude of structural plane is statistically analyzed with a combined method of rose diagram and pole equidensite diagram, and the preferred structural planes which are dominant in stability of slope were further determined by a lot of factors such as the terrain and topographical features of slope, the lithologic characters and the development of structural plane. Besides, the stereographic projection method is applied to qualitative analysis for the stability of rock slope. The results show that preferred structural plane can effectively reveal the nature of rock slope stability and provide a dimensional discriminant approach for stability of rock mass slope.

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Study on the Influence of Rainfall Infiltration on the High rock Slope of Open-pit Mine Stability using a New Nonlinear Strength Reduction Method

10.21203/rs.3.rs-914757/v1 ◽

2021 ◽

Author(s):

Tianbai Zhou ◽

Lingfan Zhang ◽

Jian Cheng ◽

Jianming Wang ◽

Xiaoyu Zhang ◽

...

Keyword(s):

Rock Mass ◽

Rock Slope ◽

Reduction Method ◽

Strength Reduction ◽

Open Pit Mine ◽

Open Pit ◽

Strength Reduction Method ◽

Rock Slopes ◽

High Rock Slope ◽

The Stability

Abstract Due to long-term mining, a series of high and steep rock slopes have been formed in the open-pit mine. For high rock slopes, rainfall infiltration is the main cause of landslide. Therefore, the stability analysis of high rock slope under rainfall has become a key issue in the open-pit mine engineering. In this work, aiming at the high stress condition of high rock slope, the instantaneous internal friction angle and instantaneous cohesion of rock mass under different stress states are deduced, and the a nonlinear strength reduction method for high rock slope is established according to the relationship between normal stress and shear stress of rock mass under the Hoke-Brown criterion. The numerical calculation results show that the factor of safety (FOS) for high rock slope calculated by the proposed method is more reasonable. Taking the southwest slope of Dagushan Iron Mine as the research background, the safety factors of high rock slope under different rainfall conditions are calculated by COMSOL Multiphysics. And the stability analysis of high rock slope in open-pit mine under rainfall are carried out.

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Stability Assessment of High and Steep Cutting Rock Slopes with the SSPC Method

Advances in Civil Engineering ◽

10.1155/2021/8889526 ◽

2021 ◽

Vol 2021 ◽

pp. 1-10

Author(s):

Hongliang Tao ◽

Guangli Xu ◽

Jingwen Meng ◽

Ronghe Ma ◽

Jiaxing Dong

Keyword(s):

Slope Stability ◽

Rock Slope ◽

Equilibrium Analysis ◽

Rock Slope Stability ◽

Rock Slopes ◽

Evaluation Indexes ◽

Weathering Degree ◽

Slope Rock ◽

The Stability

The stability of high rock slopes has become a key engineering geological problem in the construction of important projects in mountainous areas. The original slope stability probability classification (SSPC) system, presented by Hack, has made obvious progress and been widely used in rock slope stability analysis. However, the selection and determination of some evaluation indexes in the original SSPC method are usually subjective, such as intact rock strength and weathering degree. In this study, the SSPC method based on geological data obtained in the prospecting tunnels was presented and applied. According to the field survey and exploration of the prospecting tunnels, the weathering degree of the slope rock mass was evaluated. The empirical equation for the maximum stable height of the slope was applied to the slope stability evaluation in the presented SSPC method. Then, the slope stability probability of numerous cutting slopes in the sandstone unit was evaluated using the presented system. Results of the Geostudio software based on the limited equilibrium analysis of the investigated slopes were compared with the results obtained by the SSPC method. The results indicate that the SSPC method is a useful tool for the stability prediction of high and steep rock slopes.

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STABILITY OF RUBBLE MOUND BREAKWATERS WITH A BERM

Coastal Engineering Proceedings ◽

10.9753/icce.v33.structures.10 ◽

2012 ◽

Vol 1 (33) ◽

pp. 10

Author(s):

Marcel Van Gent ◽

Gregory M. Smith ◽

Ivo Van der Werf

Keyword(s):

Rock Slope ◽

Slope Angle ◽

Rock Slope Stability ◽

Rock Slopes ◽

Test Results ◽

Physical Model Tests ◽

Rubble Mound ◽

The Stability ◽

Rubble Mound Breakwaters ◽

Rock Size

The stability of rock slopes with a horizontal berm has been studied by means of physical model tests. This paper is focussed on the rock slope stability of the slopes above and below the berm. By applying a berm the rock size can be reduced compared to the required rock size for a straight slope without a berm. This reduction can be significant for the slope above the berm. The influence of the slope angle (1:2 and 1:4), the width of the berm, the level of the berm, and the wave steepness have been investigated. Based on the test results prediction formulae have been derived to quantify the required rock size for rubble mound breakwaters with a berm.

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Seismic stability analysis of rock slopes by yield design theory using the generalized Hoek-Brown criterion

MATEC Web of Conferences ◽

10.1051/matecconf/201814902026 ◽

2018 ◽

Vol 149 ◽

pp. 02026

Author(s):

Mounir Belghali ◽

Zied Saada

Keyword(s):

Rock Mass ◽

Stability Analysis ◽

Design Theory ◽

Rock Slope ◽

Numerical Solutions ◽

Stability Study ◽

Seismic Stability ◽

Rock Slopes ◽

The Stability ◽

Kinematic Approach

The stability of rock slope is studied using the kinematic approach of yield design theory, under the condition of plane strain and by considering the last version of the Hoek-Brown failure criterion. This criterion, which is suitable to intact rock or rock mass highly fractured regarded as isotropic and homogeneous, is widely accepted by the rock mechanics community and has been applied in numerous projects around the world. The failure mechanism used to implement the kinematic approach is a log-spiral rotational mechanism. The stability analysis is carried out under the effects of gravity forces and a surcharge applied along the upper plateau of the slope. To take account of the effects of forces developed in the rock mass during the passage of a seismic wave, the conventional pseudo-static method is adopted. This method is often used in slope stability study for its simplicity and efficiency to simulate the seismic forces. The results found are compared with published numerical solutions obtained from other approaches. The comparison showed that the results are almost equal. The maximum error found is less than 1%, indicating that this approach is effective for analyzing the stability of rock slopes. The relevance of the approach demonstrated, investigations are undertaken to study the influence of some parameters on the stability of the slope. These parameters relate to the mechanical strength of the rock, slope geometry and loading.

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