Papers by Musa Adebayo Idris
Arabian Journal of Geosciences
Deformation modulus of rock mass (Em) is an important parameter for the analysis and design of mi... more Deformation modulus of rock mass (Em) is an important parameter for the analysis and design of mining engineering projects. However, field tests for measuring deformation modulus of rock mass are difficult, time-consuming, and capital intensive. This has led to the development of numerous empirical models for estimating rock mass deformation modulus, which are in different forms and scattered in the literature. The numerous models available in the literature use different types of inputs. Therefore, this study provides a comprehensive compilation of different empirical models for estimating the deformation modulus of rock masses. The compiled models are grouped based on their type of input parameter(s) into three categories such as those using intact rock properties, rock mass classification indices, and combination of intact rock properties and rock mass classification indices. Then, a comparative analysis was performed using absolute average relative error percentage (AAREP) and v...
International Journal of Geotechnical Engineering
DOI:10.22044/jme.2021.11310.2113 The purpose of this work is to present an approach for the proba... more DOI:10.22044/jme.2021.11310.2113 The purpose of this work is to present an approach for the probabilistic stability analysis of tunnels considering the heterogeneity of geo-mechanical properties. A stochastic procedure is followed to account for the variability in the rock mass property characterization. The finite difference method is coupled with the Monte Carlo simulation technique to incorporate the randomness of rock mass properties. Moreover, a particular performance function is defined to investigate the excavation serviceability based on the permissible deformations. In order to validate the analysis, the probabilistic and the deterministic results are compared with the in-situ measurements. It can be observed that in both the probabilistic and deterministic analyses the largest displacements occur in the invert. In contrast, the smallest displacements are recorded in the sidewalls. Utilizing the performance function, the probability of failure for the invert, crown, left, a...
Geotechnical and Geological Engineering, 2021
We simulated the spatiotemporal modelling of 3D stress and strain distributions during the triaxi... more We simulated the spatiotemporal modelling of 3D stress and strain distributions during the triaxial compression laboratory test on a westerly granite sample using finite-difference numerical modelling implemented with FLAC3D software. The modelling was performed using a ubiquitous joint constitutive law with strain softening. The applied procedure is capable of reproducing the macroscopic stress and strain evolution in the sample during triaxial deformation until a failure process occurs. In addition, we calculated focal mechanisms of acoustic emission (AE) events and resolved local stress field orientations. This detailed stress information was compared with that from numerical modelling. The comparison was made based on the 3D rotation angle between the cardinal axes of the two stress tensors. To infer the differences in rotation, we applied ANOVA. We identified the two time levels as the plastic deformation phase and the after-failure phase. Additionally, we introduced the bin fa...
The electronic journal of geotechnical engineering, 2016
Stability analyses of underground rock excavations are often performed using traditional determin... more Stability analyses of underground rock excavations are often performed using traditional deterministic methods. In deterministic methods the mean or characteristics values of the input parameters a ...
This paper presents a probabilistic approach for modelling complex rock masses wherethe intrinsic... more This paper presents a probabilistic approach for modelling complex rock masses wherethe intrinsic properties are highly variable. For this study a complex orebody in aCanadian mine is used. The mec ...
Journal of Rock Mechanics and Geotechnical Engineering, 2020
Deformation modulus of rock mass is one of the input parameters to most rock engineering designs ... more Deformation modulus of rock mass is one of the input parameters to most rock engineering designs and constructions. The field tests for determination of deformation modulus are cumbersome, expensive and time-consuming. This has prompted the development of various regression equations to estimate deformation modulus from results of rock mass classifications, with rock mass rating (RMR) being one of the frequently used classifications. The regression equations are of different types ranging from linear to nonlinear functions like power and exponential. Bayesian method has recently been developed to incorporate regression equations into a Bayesian framework to provide better estimates of geotechnical properties. The question of whether Bayesian method improves the estimation of geotechnical properties in all circumstances remains open. Therefore, a comparative study was conducted to assess the performances of regression and Bayesian methods when they are used to characterize deformation modulus from the same set of RMR data obtained from two project sites. The study also investigated the performance of different types of regression equations in estimation of the deformation modulus. Statistics, probability distributions and prediction indicators were used to assess the performances of regression and Bayesian methods and different types of regression equations. It was found that power and exponential types of regression equations provide a better estimate than linear regression equations. In addition, it was discovered that the ability of the Bayesian method to provide better estimates of deformation modulus than regression method depends on the quality and quantity of input data as well as the type of the regression equation.
International Journal of Mining Science and Technology, 2021
Abstract Blasting of rocks has intrinsic environmental impacts such as ground vibration, which ca... more Abstract Blasting of rocks has intrinsic environmental impacts such as ground vibration, which can interfere with the safety of lives and property. Hence, accurate prediction of the environmental impacts of blasting is imperative as the empirical models are not accurate as evident in the literature. Therefore, there is need to consider some robust predictive models for accurate prediction results. Gene expression programming (GEP), adaptive neuro-fuzzy inference system (ANFIS), and sine cosine algorithm optimized artificial neural network (SCA-ANN) models are proposed for predicting the blast-initiated ground vibration in five granite quarries. The input parameters into the models are the distance from the point of blasting to the point of measurement (D), the weight of charge per delay (W), rock density (ρ), and the Schmidt rebound hardness (SRH) value while peak particle velocity (PPV) is the targeted output. 100 datasets were used in developing the proposed models. The performance of the proposed models was examined using the coefficient of determination (R2) and error analysis. The R2 values obtained for the GEP, ANFIS, and SCA-ANN models are 0.989, 0.997, and 0.999, respectively, while their errors are close to zero. The proposed models are compared with an empirical model and are found to outperform the empirical model.
Физико-технические проблемы разработки полезных ископаемых, 2019
This paper presents a probabilistic approach for optimizing stope design methodology while taking... more This paper presents a probabilistic approach for optimizing stope design methodology while taking into consideration the variability in the rock mass properties. For this study, a complex orebody in a Canadian mine was used. Because of the variability in the rock mass properties of the orebody, it was not possible to determine precisely, the values of geotechnical design input parameters and hence the need to utilize a probabilistic approach. Point Estimate Method (PEM), a probabilistic tool, was incorporated into numerical analysis using FLAC3D to study the deformation magnitudes of various stope geometries to determine the optimal stope geometry with a minimum ground control problem. Results obtained for the distribution of the wall deformations and the floor heaves for each option of the stope geometry were compared to select the best geometry to achieve the optimum stability condition. The methodology presented in this study can be helpful in the process of underground mine planning and optimization in complex orebody.
Mining of Mineral Deposits, 2019
Purpose. This paper presents the result of the research carried out on the effect of increasing t... more Purpose. This paper presents the result of the research carried out on the effect of increasing temperature and stresses with depth of mining on the stability of stope within the Bushveld Igneous Complex (BIC), where the South African Platinum mines are located. Methods. The stability of stope at the platinum mine was analysed using numerical modelling. A commercial geotechnical software, FLAC (Fast Lagrangian Analysis of Continua), was used for the numerical modelling to study and to understand the behaviour of the rock in the deep and hot underground excavations. The modelling is hypothetical in the sense that there are no direct field measurements of failure or displacements. However, some field data received from the mines include virgin rock temperature, in-situ stress data. Findings. The plots of the yielded zones of the model for excavations at the depths of 1073, 2835 and 5038 m revealed that there would be shear and tensile failures at 2835 and 5038 m, however, these failures will be higher at 5038 m than what will be witnessed at shallow depths. This observation could be attributed to higher in-situ stresses and virgin rock temperatures. Originality. Major researches on the platinum mine have not extensively consider the influence of the increased temperature at the ultra-depth level hence this study aims to fill the gap by studying the effect of the increased temperature and stresses on the stability of stopes at the ultra-depth levels within the BIC. Practical implications. This research showed that mining at ultra-deep levels would pose a challenge of an increase in horizontal and vertical displacements with increasing depth. It is recommended that horseshoe-shaped stopes could be preferred in such conditions to avoid high-stress concentration at the corners of the roof of the stopes, which may reduce failures from shallow-depth to ultra-depth levels. Also, based on the magnitude of convergence that will be experienced at ultra-deep mining levels (3500 to 5000 m), it is recommended that access development is located in the more competent strata, such as in mottled anorthosite with an average UCS of 82 MPa.
Mining of Mineral Deposits, 2018
Purpose. Limestone and marble are carbonate rocks with several structural and engineering applica... more Purpose. Limestone and marble are carbonate rocks with several structural and engineering applications. The physical and mechanical properties of the rocks are fundamental as they determine their suitability for various use. Temperature is one of the critical factors that could affect the properties of the rocks and consequently their engineering application. Therefore, a better understanding of how the temperature, especially when it is higher than ambient, will affect the properties of the rocks is essential. In this work, the effects of the elevated temperature on some physical and mechanical properties of the carbonate rocks have been studied. Methods. Cubic samples of the rocks were prepared and heated in a furnace to different temperatures up to 900°C at an interval of 100°C and then cooled to the room temperature for testing. Porosity, dry density and uniaxial compressive strength (UCS) of the samples were determined under the effect of the elevated temperature. The porosity and dry density were determined using the saturation and buoyancy method while the UCS was estimated from the point load index tests performed on the samples. Findings. The results of this work indicate that the elevated temperature has significant effects on the physical and mechanical properties of the rocks. The porosity of the rocks showed an increasing trend as the temperature was increased while the density steadily decreased especially at the temperature above 300°C. The UCS of the rocks also declines with increased temperature but with an intermittent increase in their strength at a specific heating temperature. Originality. Most of the available studies on Nigerian carbonate rocks are focused on the estimation of physical and mechanical properties of the rocks without considering changes in these properties when the rocks are subjected to high temperatures. This study therefore aims to fill the gap by investigating the effects of the elevated temperatures on the physical and mechanical properties of some of the Nigerian carbonate rocks. Practical implications. The results of this study further increase understanding of the effect of high temperature on carbonate rocks, and also help to identify the critical temperature at which the properties of carbonate rocks undergo significant and irreversible changes. This information is very important for restoration of valuable fire-damaged structures made of carbonate rocks.
The creation of underground mine excavation disturbs the original state of the rock mass surround... more The creation of underground mine excavation disturbs the original state of the rock mass surrounding the excavation which often leads to instability of the excavation. This poses a threat to the safety of personnel and equipment in and around such excavations. Therefore the stability of underground mine excavations has always been a major concern to geotechnical engineers. The stability of the excavations depends on physical and mechanical properties of the rock masses as well as the in situ stress condition. For stability analyses, these parameters are determined either by in situ investigations or laboratory tests. Because of the inherent uncertainties associated with natural materials such as rock masses, the precise values of the properties are never known. The sources of these uncertainties could be inherent variability caused by random process (aleatory uncertainty) or it could be a knowledge-based uncertainty (epistemic uncertainty) such as measurement error or model transfor...
The electronic journal of geotechnical engineering, 2013
Numerical modeling techniques have been applied in many mining and civil engineering projects. Tr... more Numerical modeling techniques have been applied in many mining and civil engineering projects. Traditionally, deterministic methods have been used frequently for the estimation of design or input p ...
International Journal of Coal Science & Technology
The elemental composition of coal and biomass provides significant parameters used in the design ... more The elemental composition of coal and biomass provides significant parameters used in the design of almost all energy conversion systems and projects. The laboratory tests to determine the elemental composition of coal and biomass is time-consuming and costly. However, limited research has suggested that there is a correlation between parameters obtained from elemental and proximate analyses of these materials. In this study, some predictive models of the elemental composition of coal and biomass using soft computing and regression analyses have been developed. Thirty-one samples including parameters of elemental and proximate analyses were used during the analyses to develop multiple prediction models. Dependent variables for multiple prediction models were selected as carbon, hydrogen, and oxygen. Using volatile matter, fixed carbon, moisture and ash contents as independent variables, three different prediction models were developed for each dependent parameter using ANFIS, ANN, and MLR. In addition, a routine for selecting the best predictive model was suggested in the study. The reliability of the established models was tested by using various prediction performance indices and the models were found to be satisfactory. Therefore, the developed models can be used to determine the elemental composition of coal and biomass for practical purposes.
International Journal of Coal Preparation and Utilization
International Journal of Environmental Studies
The rock mass is intrinsically variable in its physical and mechanical properties which makes it ... more The rock mass is intrinsically variable in its physical and mechanical properties which makes it complex. This complexity is evident from the spatial random distribution of the properties from any site characterization program. The precise values for these properties are never known in most cases hence most geotechnical mine designs are based on fixed or discrete values of rock mass properties for stability analysis. This traditional deterministic approach neither reflects the inherent variability nor the uncertainty in the rock mass properties. Therefore, it is desirable to utilize a probabilistic approach which provides a range of possible results based on the variability in the rock mass properties. Understanding the effect of this random distribution and variability of the properties on stope stability is essential for more realistic mine design. In this study, a series of numerical analyses using the explicit finite difference element code FLAC, have been conducted to study the...
Tunnelling and Underground Space Technology, 2015
International Journal of Mining Science and Technology, 2014
Electronic Journal of Geotechnical Engineering
Numerical modeling techniques have been applied in many mining and civil engineering projects. Tr... more Numerical modeling techniques have been applied in many mining and civil engineering projects. Traditionally, deterministic methods have been used frequently for the estimation of design or input parameters for numerical modeling. Whereas, it is known that the effect of variability and uncertainty sourced from the complex and variable nature of rock cannot be considered by deterministic approaches using single or mean value. In this paper, the authors tried to apply a probabilistic approach to consider the uncertainties and variability in rock properties. This is to make more a realistic assessment of design parameters of rock masses around an instrumented test drift in Malmberget Mine within the content of the "Rock mass -Rock support interaction project" conducted at the Division of Mining and Geotechnical Engineering, Lulea University of Technology. To calculate the design parameters GSI of rock mass, UCS and m i constant of the intact rock are considered as random vari...
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Papers by Musa Adebayo Idris