Rock Mechanics
Avinash Bhardwaj; Ajay Bhardwaj; Madhusudan Sarda; Namrata Bichewar
Abstract
Narmada valley development authority proposed a scheme under which 12.6 cumecs of water from the Hathani river (Tributary of Narmada) will be lifted to irrigate the command area. At the pumping station lies near Alirajpur, Madhya Pradesh, India, there was a need to protect the slope on both side as water ...
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Narmada valley development authority proposed a scheme under which 12.6 cumecs of water from the Hathani river (Tributary of Narmada) will be lifted to irrigate the command area. At the pumping station lies near Alirajpur, Madhya Pradesh, India, there was a need to protect the slope on both side as water thrust from the upstream side may lead to failure of the slope. This paper presents the stability analysis of the slope using GEO5 software. It was observed that the terrain at the site was a mixture of soil and rocks. The unit weight of the rock and backfill soil observed was 21 kN/m3 and 18 kN/m3. Using numerous techniques factor of safety was calculated for the particular slope and it was observed that a suitable mitigation measure needs to be provided to prevent the failure of the slope. The inclusion of a gabion retaining wall increased the slope's safety factor significantly. The proposed mitigation measure was executed at the site, and the completed wall has not shown any damage till date. The analysis of the slope's stability results, as well as its construction of the gabion retaining wall recommended as a protective measure, are presented in this work.
Rock Mechanics
Kapoor Chand; Radhakanta Koner
Abstract
In open-pit mine, safety of internal dumps is a significant pointer on the economic perspective of the overall project. It has been found in several studies that unplanned and random deposition of the overburdened material is the main reason for mishaps and failure. The study utilized unmanned aerial ...
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In open-pit mine, safety of internal dumps is a significant pointer on the economic perspective of the overall project. It has been found in several studies that unplanned and random deposition of the overburdened material is the main reason for mishaps and failure. The study utilized unmanned aerial vehicles (UAVs) to map the mine dumps, and the precise 3D geometry of the same was reconstructed to evaluate the safety using numerical methods. A framework is proposed to assess and identify the potential zone of instability in the mine dumps. The study was conducted at the open-pit mine at the Raniganj coalfield of Paschim Bardhaman in West Bengal, India. The study assessed the internal dump safety using a 3D limit equilibrium method and numerical methods. Finally, optimum parameters are suggested for the mine dumps geometry under the prevailing geo-mining conditions of the mine site. The framework proposed here for assessing critical zones in mine dumps is cost-effective, easy to use, quick, and efficient.
Areeba Qazi; Kanwarpreet Singh
Abstract
The rock mass classification system is utilized to categorize rocks, and has been used in engineering projects and stability investigations. It focuses on the parameters of rock mass and engineering applications, which include tunnels, slopes, foundations, etc. Rock mass classification is valuable in ...
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The rock mass classification system is utilized to categorize rocks, and has been used in engineering projects and stability investigations. It focuses on the parameters of rock mass and engineering applications, which include tunnels, slopes, foundations, etc. Rock mass classification is valuable in the areas where the collection of samples and yielding of observation is difficult. With the advancement in technology, various machine-based model algorithms have been used, i.e., ANN and MLR in rock mass classification from prior few years. In the present work, the rock mass classification has been discussed, i.e., rock load, stand up time, RQD, RMR, Q, GSI, SMR, and RMi along with their applications. Considering all the parameters, it is concluded that for slope stability in a poor rock condition, the applicability of GSI is sufficient when compared with RMR. GSI also provides a highly accurate valuation of geo-mechanical properties, making it a valuable tool for the engineers and geologists. Also, the RMR values obtained from the ANN model provide better results for tunnels when compared with MLR and the conventional method. The ARMR classification of Slate, Shale, Quartz Schist, Gneiss, and Calcschist at 5 different locations of the world were 51-54, 66-70, 57-60, 35, 65-70, respectively. The range for slate and shale was found to be moderately anisotropic, while quartz schist, gneiss, and calcschist were found to be slightly anisotropic and highly anisotropic.
Surya Pratap Singh; Amrit Kumar Roy
Abstract
The Himalayan mountain range is susceptible to slope instability in numerous areas due to its complicated topography, because of the existing natural conditions and human influence and intervenes. National Highway-05 is considered in this work. The area under investigation located in Rampur, district ...
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The Himalayan mountain range is susceptible to slope instability in numerous areas due to its complicated topography, because of the existing natural conditions and human influence and intervenes. National Highway-05 is considered in this work. The area under investigation located in Rampur, district Shimla, Himachal Pradesh is evaluated for slope stability. The primary purpose of this work is to maintain the slope's stability in order to protect NH-05 and the neighboring three-sided residential structures. Following the site visit, the geotechnical investigations in the form of bore holes and laboratory tests are conducted. Analysis of slope stability is commenced after interpreting the geotechnical study report. For an analytic slope stability, the studied area is divided into three sections, labelled A1-A1', B1-B1', and C1-C1'. Taking into account the geotechnical aspects of the specified research region, the mitigation design parameters for the area and the circular slip failure are calculated using the numerical modeling techniques. The software computes the safety factor for both the static and dynamic situations. As a result, preventative measures and a few improvements are suggested.
Alankrit Walia; Amrit Kumar Roy
Abstract
The complex geography of the Himalayan mountain range, along with the natural circumstances that already exist and the ways in which people have influenced and intervened in the region- makes various regions of the range vulnerable to slope instability. The slope stability of the area that is the subject ...
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The complex geography of the Himalayan mountain range, along with the natural circumstances that already exist and the ways in which people have influenced and intervened in the region- makes various regions of the range vulnerable to slope instability. The slope stability of the area that is the subject of this work is evaluated in Palampur, which is in the Kangra district of Himachal Pradesh. The primary objective of this work is to ensure that the slope remains stable so that the nearby three-sided residential structures and the highway remain protected. After the site visit, the geo-technical studies, which include testing in the form of bore holes and in the laboratory, are carried out. After evaluating the geo-technical technical report, the next step in the process is to begin the analysis of the slope's stability. In order to do an analytical analysis of the slope stability, the area has been subdivided into three portions, and labelled A-A, B-B, and C-C, respectively. Using the numerical modelling approaches, the mitigation design parameters for the area and the circular slip failure are computed. These calculations are based on the geo-technical characteristics of the studied area that have been specified. The factor of safety is calculated for both the natural and stable scenarios by the program. Because of this, some preventative steps and a few improvements are suggested.
M. Adil; S. Raza; I. Amin
Abstract
Despite the slope stability measures, rock falls are witnessed at section KM-37 of the Swat motorway (M-16), Khyber Pakhtunkhwa, Pakistan. The geotechnical data analysis of the site reveals that although the chances of plane/slope failures are reduced from 43% to 23% with the help of the existing design, ...
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Despite the slope stability measures, rock falls are witnessed at section KM-37 of the Swat motorway (M-16), Khyber Pakhtunkhwa, Pakistan. The geotechnical data analysis of the site reveals that although the chances of plane/slope failures are reduced from 43% to 23% with the help of the existing design, still there are possibilities of rock fall at the sight, which has also been witnessed during the field visits. The rock fall hazards are assessed through field tests and simulation, and significant stabilization measures are suggested. The rock fall tests are conducted, and then using the data obtained, the rock fall simulation is carried out using GeoRock 2D®. From a combination of the kinematic analysis and rock fall simulation, the hazard level along the slope ranges from moderate to high. The reason for this is the increasing velocity of the falling boulder and the impact of energy at the bottom of the slope. This is an indication of the risk, as the most hazardous area is at the toe of the slope, where the highway road is the main element at risk. Rock boulders of different shapes and sizes are released from a couple of benches in order to check their impacts on the highway. Based on the simulation, it is concluded that the spherical shaped boulders are released from higher benches covering more horizontal distances and reaching the highway with a higher bouncing heights at the toe of the slope than the cylindrical shaped boulders. The maximum bounce height of 7 m has been recorded at the toe of the slope. In order to reduce the impacts of energy and bounce heights of the boulders striking the slope surface, certain mitigation measures are suggested like a ditch of a specific size filled with sand or fine debris at the toe of the slope. Draping wire mesh on the slope surface and a retaining wall or fence would be greatly helpful and economical to reduce the rock falling hazards along the road side at section KM-37 of the Swat motorway.
H. Haghgouei; A. Reza Kargar; M. H. Khosravi; M. Amini
Abstract
In many engineering constructions, the foundations should be built adjacent to each other. Therefore, the effect of interfering of close foundations should be considered in the design stage. In this research work, the effect of interference of closely separated foundations resting on a slope on the elastic ...
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In many engineering constructions, the foundations should be built adjacent to each other. Therefore, the effect of interfering of close foundations should be considered in the design stage. In this research work, the effect of interference of closely separated foundations resting on a slope on the elastic settlement is investigated by considering a semi-analytical solution. The distribution of stress due to the footing pressure in the slope is computed by a proposed Airy stress function, and then by employing the finite difference scheme, the displacement of the footings is calculated. The results obtained show that by increasing the distance between the foundations, the interference influence on the ratio of settlement will be diminished. However, this behavior is highly linked to the slope characteristics. For a slope with a height of 10 times of footing width, beyond an S/B ratio larger than 10, the effect of interference is not tangible, and the footings behave like an isolated foundation. By decreasing the slope height, this behavior will occur at a lower S/B.
K.S. Shah; M. H. Mohd Hashim; K.S. Ariffin; N. F. Nordin
Abstract
The stability analysis of rock slopes is a complex task for the geotechnical engineers due to the complex nature of the rock mass in a tropical climate that often has discontinuities in several forms, and consequently, in several types of slope failures. In this work, a rock mass classification scheme ...
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The stability analysis of rock slopes is a complex task for the geotechnical engineers due to the complex nature of the rock mass in a tropical climate that often has discontinuities in several forms, and consequently, in several types of slope failures. In this work, a rock mass classification scheme is followed in a tropical environment using the Rock Mass Rating (RMR) and Geological Strength Index (GSI) combined with the kinematic investigation using the Rocscience Software Dips 6.0. The Lafarge quarry is divided into ten windows. In the RMR system, the five parameters uniaxial compressive strength (UCS), rock quality designation (RQD), discontinuity spacing, discontinuity condition, and groundwater conditions are investigated. The RMR values range from 51 to 70 (fair to good rock mass), and the GSI values range from 62 to 65 (good to fair rock mass). There is a good and positive correlation between RMR and GSI. The kinematic analysis reveals that window A is prone to critical toppling, window H to critical wedge-planar failure, and window G to critical wedge failure. From the results obtained, it can be concluded that the kinematic analysis combined with the rock mass classification system provides a better understanding to analyze the rock slope stability in a tropical climate compared with considering the rock mass classification system individually.
Rock Mechanics
A. Alikhani; M. Taheri Moghadder; H. Mohammadi
Abstract
One of the most effective parameters in economics of open-pit mines is the pit slope angle, so that the slope angle more than the optimum value increases the probability of a large failure in the pit wall and the slope angle less than the optimum value leads to increasing stripping ratio and reducing ...
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One of the most effective parameters in economics of open-pit mines is the pit slope angle, so that the slope angle more than the optimum value increases the probability of a large failure in the pit wall and the slope angle less than the optimum value leads to increasing stripping ratio and reducing net present value of mine. Therefore, in this paper, considering the limit equilibrium methods of modified Bishop and modified Janbu and numerical models of the slope stability analysis, the effect of overall slope angle on the Economics of open pit mines was investigated. In addition, it was shown that selecting the overall slope angle less than the optimum value leads to reducing the depth of open-pit mining (the ultimate pit depth) and consequently, reducing the net present value of mine. Finally, in homogenous and Isotropic media, the results of Bishop and Janbu and numerical modeling are close together.
Rock Mechanics
H. Zebarjadi Dana; R. Khaloo Kakaie; R. Rafiee; A.R. Yarahmadi Bafghi
Abstract
Slope stability analysis is one of the most important problems in mining and geotechnical engineering. Ignoring the importance of these problems can lead to significant losses. Selecting an appropriate method to analyze the slope stability requires a proper understanding of how different factors influence ...
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Slope stability analysis is one of the most important problems in mining and geotechnical engineering. Ignoring the importance of these problems can lead to significant losses. Selecting an appropriate method to analyze the slope stability requires a proper understanding of how different factors influence the outputs of the analyses. This paper evaluates the effects of considering the real geometry, changes in the mesh size, and steepness of the slope, as the dimensional effects, and changes in the geomechanical parameters, as the media effects on the global slope stability of an open-pit mine using finite difference methods with a strength reduction technique. The case study is the Tectonic Block I in the old pit (steep slope) and the redesigned new pit (gentle slope) of the Choghart iron mine. In the first step, a series of 2D and 3D slope stability analyses are performed and compared in terms of safety and potential failure surface. The results obtained show that by considering the real geometry of the slope, the FOS3D/FOS2D ratio (3D-effect) is more than 1 in the all cases. The 3D-effect in the new pit is smaller than that in the old one. In the next step, sensitivity analysis of the cohesion and the friction angle is performed for the 2D and 3D analyses. The results obtained show that the sensitivity of the analyses in terms of the 3D-effect to the change in the friction angle, especially in a low-friction angle, is more significant than that to the change in the cohesion.
Rock Mechanics
M. M. Samieinejad; N. Hosseini; K. Ahangari
Abstract
In order to analyze the slope stability in open-pit mines, the structural parameters of rock mass such as persistence and spatial orientation of discontinuities are characterized through field surveys, which involve spending high costs and times as well as posing high risks of rock toppling and rock ...
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In order to analyze the slope stability in open-pit mines, the structural parameters of rock mass such as persistence and spatial orientation of discontinuities are characterized through field surveys, which involve spending high costs and times as well as posing high risks of rock toppling and rock fall. In the present work, a new application of terrestrial digital photogrammetry is introduced for characterizing the rock mass structural parameters through preparing photogrammetry images from open-pit walls and building stereomodels. The data extracted from processing the stereo-model generations using photogrammetry images with different focal distances are highly consistent with the data collected through field surveys. However, it must be noted that the weather conditions, natural lighting angle, and applied observation scale may considerably affect the results obtained from stereomodel processing. Nevertheless, by taking into account the parameters such as time, cost, and full access to the required data, this new method can effectively be used in the estimation of rock mass structural parameters for analysis of steep slopes in open pits.
H. Fattahi
Abstract
Slope stability analysis is an enduring research topic in the engineering and academic sectors. Accurate prediction of the factor of safety (FOS) of slopes, their stability, and their performance is not an easy task. In this work, the adaptive neuro-fuzzy inference system (ANFIS) was utilized to build ...
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Slope stability analysis is an enduring research topic in the engineering and academic sectors. Accurate prediction of the factor of safety (FOS) of slopes, their stability, and their performance is not an easy task. In this work, the adaptive neuro-fuzzy inference system (ANFIS) was utilized to build an estimation model for the prediction of FOS. Three ANFIS models were implemented including grid partitioning (GP), subtractive clustering method (SCM), and fuzzy c-means clustering method (FCM). Several important parameters such as cohesion coefficient, internal angle of friction, slope height, slope angle, and unit weight of slope material were utilized as the input parameters, while FOS was used as the output parameter. A comparison was made between these three models, and the results obtained showed the superiority of the ANFIS-SCM model. Also performance of the ANFIS-SCM model was compared with multiple linear regression (MLR). The results obtained demonstrated the effectiveness of the ANFIS-SCM model.
