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3-D modeling of rock.burst in pillar No. 19 of Fetr6 chromite mine

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International Journal of Mining Science and Technology 2013年第2期23卷 237-242页

作者： S. Dehghan k. Shahriar P. Maarefvand k. goshtasbi Department of Mining Engineering Science and Research Branch Islamic Azad University Department of Mining and Metallurgical Engineering Amirkabir University of Technology Department of Mining Engineering Tarbiat Modares University

Fetr6 is an underground mine in which chromite is extracted using stope and pillar mining method. Despite of all improving work. such as roof supporting and replacing of ore pillars with concrete pillars, pillar No. 19 failed and other pillars failed progressively as a domino effect and 4000 m2 of mine collapsed within a few minutes, consequently. For detail investigation, two 3-D numerical models were developed by 3Dec. The first, a base model, was used for estimation of stress on pillars just before failure and the other for investigation of rock.burst in pillar No. 19. The results show that discontinuity parameters such as friction angle and shear stiffness is critical parameters in this pillar failure. In addition, it indicates that W/H ratio equal 0.3, the lack.of ore extraction strategy and inadequate roof support are the major reasons for this failure. In this paper, the procedure of study was described.

关键词： Rock.burst Stope and pillar 3-D modeling 3Dec Domino effect Faryab mine

Settlement modeling in central core rock.ill dams by new approaches

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International Journal of Mining Science and Technology 2016年第4期26卷 703-710页

作者： Behnia D. Ahangari k. goshtasbi k. Moeinossadat S.R. Behnia M. Department of Mining Engineering Science and Research BranchIslamic Azad University Department of Mining Engineering Tarbiat Modares UniversityFaculty of Engineering Department of Civil Engineering Qaemshahr BranchIslamic Azad University

One of the most important reasons for the serious damage of embank.ent dams is their impermissible ***,it can be stated that the prediction of settlement of a dam is of paramount *** study aims to apply intelligent methods to predict settlement after constructing central core rock.ill *** were made in this research to prepare models for predicting settlement of these dams using the information of 35 different central core rock.ill dams all over the world and Adaptive Neuro-Fuzzy Interface System(ANFIS) and Gene Expression Programming(GEP) *** such as height of dam(H) and compressibility index(Ci) were considered as the input ***,a form was designed using visual basic software for predicting dam *** respect to the accuracy of the results obtained from the intelligent methods,they can be recommended for predicting settlement after constructing central core rock.ill dams for the future plans.

关键词： Settlement Adaptive Neuro-Fuzzy Interface System(ANFIS)Gene Expression Programming (GEP)Visual Basic (VB)

Numerical Modeling of the Stability of Horizontal Multidrain Oil Wells

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China Ocean Engineering 2015年第5期29卷 719-732页

作者： Ayub ELYASI k.mran goshtasbi Faculty of Engineering Tarbiat Modares University

The stability of the horizontal multidrain wells is a crucial issue and several factors are involved in this matter, including in-situ stresses, magnitude and distribution as well as the mainbore trajectories. In this paper, this issue is evaluated by assuming different circumstances for the above mentioned factors, based on finite difference threedimensional modeling by using the finite difference numerical software, FLAC3 D. The stability of the mainbore and lateral branches is analyzed based on the Normalized Yielded Zone Area（NYZA） criterion, i.e. the ratio of the surrounding yielded cross-sectional area to the initial area of the well. Optimum mud pressures are obtained in the mainbore and lateral branches in different mainbore trajectories under three in-situ stress regimes. In addition, the stability of the junction where the lateral branches are bifurcated from the mainbore is assessed in those situations. The optimum trajectory of the mainbore, in which the junction has obtained the most stable condition, is selected in each stress regime. It was concluded that in the Normal Faulting（NF） stress regime, the mainbore and junction stability varies in relation to the mainbore trajectories, inversely. However, in the other two stress regimes, i.e. Strik. Slip（SS） and Reverse Faulting（RF）, the variations of the mainbore and junction stability are in the same trend with respect to the mainbore trajectory deviations.

关键词： multidrain wells in-situ stresses NYZA mainbore lateral branches

A model to determine hole spacing in the rock.fracture process by non-explosive expansion material

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International Journal of Minerals,Metallurgy and Materials 2011年第5期18卷 509-514页

作者： Shobeir Arshadnejad k.mran goshtasbi Jamshid Aghazadeh Department of Mining Engineering Mahallat BranchIslamic Azad UniversityMahallat ***Iran Department of Mining Engineering Tarbiat Modares UniversityTehran 14115-143Iran Department of Mining and Metallurgical Engineering Amirkabir University of TechnologyTehran ***Iran

The application of the non-explosive expansion material （NEEM） is widely used as the controlled fracture method in quarry min- ing, especially in hard rock.. The pressure of NEEM is an important parameter in causing rock.fracture. An empirical model based on hole spacing was developed to determine the pressure of NEEM in the rock.fracture process. Primarily, the empirical model was developed by the mathematical method, utilizing dimensional analysis. Then, the Phase2 code, which is based on the finite element method, was utilized to predict crack.growth in rock.. The results of numerical analysis show slight deviations from the empirical model. Hence, the polynomial re- gression analysis was used to modify the model. Finally, the modified model shows a good agreement with the results gained from numerical modeling.

关键词： rock.fracture dimensional analysis finite element method non-explosive quarry mining

3-D numerical modelling of Domino failure of hard rock.pillars in Fetr6 Chromite Mine, Iran, and comparison with empirical methods

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Journal of Central South University 2013年第2期20卷 541-549页

作者： S.Dehghan k.Shahriar P.Maarefvand k.goshtasbi Department of Mining Engineering Science and Research BranchIslamic Azad University Department of Mining and Metallurgical Engineering Amirkabir University of Technology Department of Mining Engineering Tarbiat Modares University

Fetr6 is an underground mine using the stope-and-pillar mining method. As there was some evidence regarding pillar failure in this mine, improving work. such as roof support and replacing existing pillars with concrete pillars (CP) were carried out. During the construction of the second CP, in the space between the remaining pillars, one of the pillars failed leading to the progressive failure of other pillars until 4 000 m 2 of mine had collapsed within a few minutes. In this work. this phenomenon is described by applying both numerical and empirical methods and the respective results are compared. The results of numerical modelling are found to be closer to the actual condition than those of the empirical method. Also, a width-to-height (W/H) ratio less than 1, an inadequate support system and the absence of a detailed program for pillar recovery are shown to be the most important causes of the Domino failure in this mine.

关键词： hard rock Domino failure numerical modelling empirical method stope pillar extraction ratio W/H ratio

Numerical assessment of the mechanical stability in vertical,directional and horizontal wellbores

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International Journal of Mining Science and Technology 2013年第6期23卷 937-942页

作者： k.mran goshtasbi Ayub Elyasi Ali Naeimipour Department of Mining Engineering Tarbiat Modares University School of Energy and Mineral Engineering Pennsylvania State University

In this research the stability of wellbore is evaluated in seven different stress regimes and diverse orientations using FLAC3D *** normalized yielded zone area(NYZA.i.e.,the ratio of surrounding yielded cross-sectional area to initial area of wellbore)is determined for different mud pressures as well as diverse orientations of *** means of MATLAB software the best curve is fitted to the recorded points and then the optimized mud pressure is calculated using these *** optimized orientation is selected considering these *** the mud pressure resulted from this method was compared with the mud pressure obtained from the Mogi-Coulomb criterion and then with the fields *** minimum allowable mud pressure obtained from the NYZA criterion is close to actual data and the value obtained from the Mogi-Coulomb ***,the NYZA is considered to be an appropriate criterion for wellbore stability analysis.

关键词： NYZA Mud pressure Optimum orientation Stress regime

Passive seismic velocity tomography on longwall mining panel based on simultaneous iterative reconstructive technique (SIRT)

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Journal of Central South University 2012年第8期19卷 2297-2306页

作者： N.Hosseini k.Oraee k.Shahriar k.goshtasbi Department of Mining Engineering South Tehran BranchIslamic Azad UniversityTehran 17776-13651Iran Department of Management University of StirlingStirling FK94LAUK Department of Mining and Metallurgical Engineering Amirkabir University of TechnologyTehran 15916-34311Iran Department of Mining Engineering Tarbiat Modares UniversityTehran 14115-111Iran

Mining operation, especially underground coal mining, always has the remark.ble risk. of ground control. Passive seismic velocity tomography based on simultaneous iterative reconstructive technique （SIRT） inversion is used to deduce the stress redistribution around the longwall mining panel. The mining-induced microseismic events were recorded by mounting an array of receivers on the surface, above the active panel. After processing and filtering the seismic data, the three-dimensional tomography images of the p-wave velocity variations by SIRT passive seismic velocity tomography were provided. To display the velocity changes on coal seam level and subsequently to infer the stress redistribution, these three-dimensional tomograms into the coal seam level were sliced. In addition, the boundary element method （BEM） was used to simulate the stress redistribution. The results show that the inferred stresses from the passive seismic tomograms are conformed to numerical models and theoretical concept of the stress redistribution around the longwall panel. In velocity tomograms, the main zones of the stress redistribution arotmd the panel, including front and side abutment pressures, and gob stress are obvious and also the movement of stress zones along the face advancement is evident. Moreover, the effect of the advance rate of the face on the stress redistribution is demonstrated in tomography images. The research result proves that the SIRT passive seismic velocity tomography has an ultimate potential for monitoring the changes of stress redistribution around the longwall mining panel continuously and subsequently to improve safety of mining operations.

关键词： longwall mining passive seismic velocity tomography simultaneous iterative reconstructive technique (SIRT) boundary element method stress redistribution ground control

Appropriate extent of surgery for aspirinexacerbated respiratory disease

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World Journal of Otorhinolaryngology-Head and Neck.Surgery 2020年第4期6卷 235-240页

作者： Ethan G.Muhonen k.odayar goshtasbi Peter Papagiannopoulos Edward C.k.an Department of Otolaryngolosy-Head and Neck.Sursery University of CaliforniaIrvineUSA Department of Otolaryngolosy-Head and Neck.Surgery Rush University Medical CenterChicagoILUSA

The current literature lack. strong guidelines regarding surgical management of patients with aspirin-exacerbated respiratory disease(AERD),who present with the clinical triad of chronic rhinosinusitis with nasal polyposis(CRSwNP),bronchial asthma,and aspirin/nonsteroidal anti-inflammatory drug *** further define the effectiveness of sinus surgery in treating AERD patients,this review article discusses current evidence regarding outcomes associated with more extensive surgery,the benefits of frontal sinus surgery on polyposis,and the role of Draf III *** studies suggest that Draf III frontal sinusotomy may be an efficacious early intervention due to increased neo-ostial patency and subsequent distribution of topical *** studies that further investigate the efficacy and safety of extensive surgery in AERD patients are warranted.

关键词： Endoscopic sinus surgery Draf III Aspirin exacerbated respiratory disease Chronic sinusitis Nasal polyps Extent of surgery

The Effect of Alluvial Foundation on the Earth Dams Settlement

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Open Journal of Geology 2017年第3期7卷 360-373页

作者： Masoud Ghaemi k.veh Ahangari Ali Noorzad k.mran goshtasbi Department of Mining Engineering Science and Research Branch Islamic Azad University Tehran Iran Faculty of Water and Environmental Engineering Shahid Beheshti University Tehran Iran Faculty of Mining Engineering Tarbiat Modares University Tehran Iran

Careful monitoring in the earth dams, to measure deformation caused by settlement and movement has always been a concern for engineers in the field. In order to measure settlement and deformation of earth dams, usually the precision instruments of settlement set and combined Inclinometer that is commonly referred to IS instrument, will be used. In some dams, because the thick.ess of alluvium is high and there is no possibility of alluvium removal (technically and economically and in terms of performance), there is no possibility to place the end of IS instrument (precision instruments of Inclinometer-settlement set) in the rock.foundation. Inevitably, have to accept installing pipes in the weak.and the deformable alluvial foundation that this leads to errors in the calculation of the actual settlement (absolute settlement) in different parts of the dam body. The purpose of this paper is to present new and refine criteria for predicting settlement and deformation in earth dams. The study is based on conditions in three dams with a deformation quite alluvial (Agh Chai, Narmashir and Gilan-e Gharb) to provide settlement criteria affected by alluvial foundation. To achieve this goal, the settlement of dams was simulated by using finite difference method with FLAC3D software and then the modeling results were compared with reading IS instrument. In the end, the caliber of the model and validate the results, by using regression analysis techniques and scrutinized modeling parameters with real situations and then by using MATLAB software and Curve Fitting Toolbox, a new criteria for the settlement based on elasticity modulus, cohesion, friction angle, density of earth dam and alluvial foundation was obtained. The results of these studies show that, by using the new criteria measures, the amount of settlement and deformation for the dams with alluvial foundation can be corrected after instrument readings and the error rate in reading IS instrument can be greatly reduced.

关键词： Earth Dam Alluvial Foundation Settlement Finite Difference FLAC3D MATLAB Curve Fitting Refine Criteria IS Instrument