Papers by Levent Tutluoglu
Engineering Geology, 2010
ABSTRACT The major borax producer, Eti Mining Co. of Turkey, planned to construct an export stock... more ABSTRACT The major borax producer, Eti Mining Co. of Turkey, planned to construct an export stock site located near the Bandirma Harbor in the northwestern of Turkey. During this construction, some stability problems were encountered. To analyze the stability problems and to assess the engineering properties of soil in the stock site geotechnical investigations were started. As a part of geotechnical investigations one of the most common field tests, the standard penetration tests (SPT), was conducted for soil exploration. In this study, the field is geostatistically simulated to assess the uncertainty associated with the spatial variability of SPT results. Multiple probable realizations of SPT values are generated using sequential Gaussian simulation. Using 122 NSPT data in the borax stockpile site, the characteristics observed in the available data are reproduced in a manner that the heterogeneity of SPT within the field is honored. The estimated NSPT data can also be used for other purposes such as determination of bearing capacity, and estimation of soil strength parameters.
An Investigation Of The Mechanisms Of Water Jet Assistance On The Rock Cutting Process
Reasons for the dramatic reductions in the forces acting on drag bits when water jets at moderate... more Reasons for the dramatic reductions in the forces acting on drag bits when water jets at moderate pressures (less tahn 70 MPa) are used to assist a rock cutting operation, are investigated. The possibility that stress corrosion crack (SCC) plays a role in these bit force reductions is ...
Geotechnical Investigations at two NPP Sites in Turkey
In this study, the results of a new permanent support system design for the re-use of an existing... more In this study, the results of a new permanent support system design for the re-use of an existing mine drainage tunnel driven through marl rock unit is presented. The tunnel which is 1050 meters long was driven by drilling and blasting and temporarily supported by I section steel sets about two years ago. It is now planned by the mine management to be used as a transportation tunnel for many years. Along the tunnel route, two different rock mass units which were named as marl and graywacke units were encountered.This paper presents the only results of permanent support design for marl rock unit. Numerical modeling with a 2D finite element package was employed to simulate different loading conditions, including the surcharge load due to the mine waste expected to be applied on the surface over the tunnel in future. Surcharge load was interestingly moving the whole model frame down including the overall tunnel section, and therefore, the location of the bottom boundary of the model fr...
Mechanical rockcutting with and without high pressure water jets /
Thesis (Ph. D. in Engineering)--University of California, Berkeley, Dec. 1984. Includes bibliogra... more Thesis (Ph. D. in Engineering)--University of California, Berkeley, Dec. 1984. Includes bibliographical references (leaves 156-162).
Investigation of Large Scale Slope Failure Mechanisms and Numerical Modelling for Safe Design of Slopes in a Lignite Mine
Geotechnical analysis plays an important role in determining mining method selection. This study ... more Geotechnical analysis plays an important role in determining mining method selection. This study presents the geotechnical design analysis of a potential U/G iron ore Mentes Mine at Yahyali province of Kayseri district in Turkey. Iron ore body is initially planned to be mined by using long hole mining method. Detailed geotechnical site investigation and laboratory work are carried out to assess the applicability of the selected mining method. Diamond-drilled borehole cores are logged and geotechnical characterization of rock mass units is conducted by assigning RMR89 and Q classification values to the basic rock units. Extensive laboratory test work is carried out to find the geotechnical material properties of the ore and the wall rocks. Based on the results of rock mass classification efforts, empirical stope dimensioning work and detailed numerical (finite element) modeling for the stability analyses of pillar-stope layouts and overall mine are conducted. Finally, it is concluded that planned long hole stope dimensions appear to be unsafe and drift and fill mining method appears to be more suitable for this project.
Slope failures may cause production interruption and equipment loss in addition to the potential ... more Slope failures may cause production interruption and equipment loss in addition to the potential danger for personnel. A potential instability in parts of the slopes near residential areas may result in damage on the surface utility structures as well as legal issues. In Orhaneli Surface Lignite Mine, Altintas village is located close to the existing southwest slope of Panel SA-6 in Sagirlar Sector. South-east slope which is also near Altintas village had some slope stability problems. A local slide restricted to the surface layers of the south-east slope occurred during the overburden removal operations. Back analysis of this small slide was conducted with geotechnical parameters estimated from a previous major slide in another sector of the same surface lignite mine establishment. Safe and uninterrupted future production in Sagirlar SA-6 panel and assessment of the preventive measures to protect the structures of Altintas Village are the main targets in this work. Potential for a possible slope failure and its effects on structures of Altintas village are assessed and some remediation measures are proposed. Remediation suggestions are predicted to increase safety against effects of a potential slope failure. Potential risks are evaluated by means of comparing safety factors which are determined by modeling the different slope geometries and preventive measures with a program using limit equilibrium methods. Slope stability analyses in this work are conducted by Rocscience SLIDE program which is a method of slices program based on the limit equilibrium techniques. Optimum slope geometries for different production directions and alternatives are investigated and alternative solutions for the improved safety of mine operations and nearby structures of Altintas Village are assessed.
Can Lignite Surface Mine of Turkish Coal Enterprises (TKI) is located on the northwestern Turkey.... more Can Lignite Surface Mine of Turkish Coal Enterprises (TKI) is located on the northwestern Turkey. Lignite with about 9.3 billion tons of reserve is a major source for energy production in Turkey. Turkish Coal Enterprises produces about 60% of the country's yearly production. Can Surface Lignite Mine which is planned to produce approximately 2.5 million tons of 3000 kcal/kg coal, will be one of the main production areas of TKI. Slope failures in the form of large landslides can cause serious interruptions in production of lignite. Major landslides commonly occur in TKI Can Lignite Mine. Back analysis of such slides can provide information about the mechanisms of such slides, so that preventive measures can be taken to reduce the future risks of landslides in the lignite basin.
Design of weak rock slope at BLI open pit lignite mine in Turkey
Undrained Stability of Residual Soil in Karst
Sinkholes and the Engineering and Environmental Impacts of Karst, 2008
Mine Planning and Equipment Selection, 2014
Geotechnical analysis plays an important role in determining mining method selection. This study ... more Geotechnical analysis plays an important role in determining mining method selection. This study presents the geotechnical design analysis of a potential U/G iron ore Mentes Mine at Yahyali province of Kayseri district in Turkey. Iron ore body is initially planned to be mined by using long hole mining method. Detailed geotechnical site investigation and laboratory work are carried out to assess the applicability of the selected mining method. Diamond-drilled borehole cores are logged and geotechnical characterization of rock mass units is conducted by assigning RMR89 and Q classification values to the basic rock units. Extensive laboratory test work is carried out to find the geotechnical material properties of the ore and the wall rocks. Based on the results of rock mass classification efforts, empirical stope dimensioning work and detailed numerical (finite element) modeling for the stability analyses of pillar-stope layouts and overall mine are conducted. Finally, it is concluded that planned long hole stope dimensions appear to be unsafe and drift and fill mining method appears to be more suitable for this project.
Under compression, gathering data related to the post-failure part of the stress–strain curve req... more Under compression, gathering data related to the post-failure part of the stress–strain curve requires stiff servo-controlled testing systems. In unconfined conditions, data related to the post-peak region of the intact rock parameters are not common as pre-peak and peak state parameters of stress–strain behavior. For problems involving rock in the failed state around structures, proper choice of plastic constitutive laws and post-failure parameters is important for the modeling of the failed state. The aim is to relate commonly used intact rock parameters of pre-failure (tangent modulus E i and secant modulus E s) and peak strength (σ ci) states to parameters of the post-failure state under unconfined compression. Post-failure parameters are the drop modulus (D pf), representing the slope of the falling portion in brittle state, residual strength (σ cr), and dilatancy angle (ψ°). Complete stress–strain curves were generated for various intact rock of different origin. Seventy-three post-failure tests were conducted. Samples included in the testing program were chosen to represent rocks of different origin. Specimens of granite, rhyodacite, dunite, quartzite series, glauberite, argillite, marl, and lignite were used in the tests. The results from the pre-failure and peak state testing parts were processed and compared to the post-failure stress–strain parameters. For the estimation of post-failure parameters in terms of the pre-peak and peak states, the functional relations were assessed. It was found that the drop modulus D pf increases with rock strength σ ci, following a power function with an approximate power of two. With an exponential trend, the D pf/E s ratio increases with decreasing E i/σ ci ratio. Relations estimating the residual strength and dilatancy from the pre-peak and peak state parameters are in logarithmic and exponential functional forms, respectively.
Stress intensity factors of specimen models with various external diameters, inner hole diameters... more Stress intensity factors of specimen models with various external diameters, inner hole diameters, and extents of flattened loading boundaries for the modified ring testing method for mode I fracture are computed by finite element modeling. Effects of boundary conditions and geometric factors on stress intensity factor computation are analyzed. Parametric expressions are proposed to estimate critical crack length position and corresponding maximum stress intensity factor. An expression in terms of inner hole and specimen diameter, and loading angle is developed for estimation of maximum stress intensity factor. Mode I fracture toughness tests with modified ring method are conducted on two different rock types; andesite and marble. Results of the modified ring tests with different external specimen diameters are compared to the results obtained by the cracked chevron notched Brazilian disk method. Geometric parameters of modified ring specimens yielding fracture toughness results close to the results of the suggested method are identified. Fracture toughness of large diameter specimens with small inner hole sizes is found to be higher than the results of the suggested method. A similar trend is observed with decreasing width of loaded boundaries. Effects of specimen and inner hole size, and loaded and free boundaries on fracture process zone and fracture toughness are discussed.
A new method called the straight notched disk bending method is developed for mode I fracture tou... more A new method called the straight notched disk bending method is developed for mode I fracture toughness determination using rock cores. Disk specimens of andesite and marble having a single straight edge notch were subjected to three-point bending loads. Dimensionless stress intensity factor estimations and fracture toughness tests were conducted for different notch lengths, span lengths, thicknesses and diameters of the cylindrical rock specimens. Stress intensity factors were computed by three-dimensional finite element modeling and the results were presented for a wide range of specimen geometrical parameters. Results of experiments were compared to the results of well-known mode I fracture toughness testing methods. For specimens having thickness equal to the radius, mode I fracture toughness was lower and close to the results obtained by semi-circular bending method. When thickness was increased and doubled, mode I fracture toughness increased and approached to the value found by the suggested cracked chevron notched Brazilian disk method. Advantages of the new method included easy specimen preparation and testing procedure, stiffer specimen geometry, smaller fracture process zone, and flexibility of the specimen geometry for the investigation of the size effect behavior.
With about 9.3 billion tons of reserve, lignite is a major source for energy production in Turkey... more With about 9.3 billion tons of reserve, lignite is a major source for energy production in Turkey. The Afs -in-Elbistan lignite basin, containing 47% of the overall lignite reserve in Turkey, lies in the Afs -in and Elbistan districts as a part of Kahramanmaras -. The new C -öllolar opencast mine is in the Afsin-Elbistan lignite basin, and this mine will be the second mining activity in the basin after the active Kıs -laköy opencast mine. The new mine will meet the coal consumption of the Elbistan B power plant. Input parameters for slope stability analysis are essential, and so they must be determined accurately and precisely. Field investigations, laboratory testing and back analyses are vital instruments for the input parameters. This study presents the results of slope stability analysis via finite difference code and a limit equilibrium software for the soil slopes of the Elbistan-C -öllolar lignite mine. The basic input parameters, cohesion and friction angle, were determined in the soil mechanics laboratory. By back analyses of a large scale slope failure, mobilized friction angles for a critical weak clay layer under the lignite seam were determined accurately by using the 2D limit equilibrium method and 3D finite difference models. Results of the friction angles were compared in order to check the effectiveness of commonly used 2D approaches in handling the slope problems. Differences in the results of the mobilized friction angles for the weak clay layer were more than 30%. The 3D models indicated that the mobilized friction angle during the major slope failure was substantially lower than the friction angle generated by the 2D limit equilibrium method.
Rock Mechanics and Rock Engineering, 2014
Under compression, gathering data related to the post-failure part of the stress-strain curve req... more Under compression, gathering data related to the post-failure part of the stress-strain curve requires stiff servo-controlled testing systems. In unconfined conditions, data related to the post-peak region of the intact rock parameters are not common as pre-peak and peak state parameters of stress-strain behavior. For problems involving rock in the failed state around structures, proper choice of plastic constitutive laws and post-failure parameters is important for the modeling of the failed state. The aim is to relate commonly used intact rock parameters of pre-failure (tangent modulus E i and secant modulus E s ) and peak strength (r ci ) states to parameters of the post-failure state under unconfined compression. Post-failure parameters are the drop modulus (D pf ), representing the slope of the falling portion in brittle state, residual strength (r cr ), and dilatancy angle (w°). Complete stress-strain curves were generated for various intact rock of different origin. Seventy-three post-failure tests were conducted. Samples included in the testing program were chosen to represent rocks of different origin. Specimens of granite, rhyodacite, dunite, quartzite series, glauberite, argillite, marl, and lignite were used in the tests. The results from the pre-failure and peak state testing parts were processed and compared to the post-failure stress-strain parameters. For the estimation of post-failure parameters in terms of the pre-peak and peak states, the functional relations were assessed. It was found that the drop modulus D pf increases with rock strength r ci , following a power function with an approximate power of two. With an exponential trend, the D pf /E s ratio increases with decreasing E i /r ci ratio. Relations estimating the residual strength and dilatancy from the prepeak and peak state parameters are in logarithmic and exponential functional forms, respectively.
Journal of Terramechanics, 2008
Specific energy is simply defined as the work done per unit volume of rock excavated. Specific en... more Specific energy is simply defined as the work done per unit volume of rock excavated. Specific energy is an important performance parameter as it relates cutting force to the amount of rock excavated. In this paper the development of a new rippability classification system for coal measure rock based on specific energy is presented. Extensive field and laboratory studies were conducted at six different lignite open pit mines and rock mechanics laboratory. Since both ground and machine properties are incorporated, the rippability classes of rocks and the approximate hourly ripper productions of different dozer types can be assessed by using the developed system.
Stability Charts for the Collapse of Residual Soil in Karst
Journal of Geotechnical and Geoenvironmental Engineering, 2009
Slope stability analysis of a borax stockpile site
International Journal of Mining and Mineral Engineering, 2009
ABSTRACT Stability investigations were conducted for a slope at the back of a borax stockpile sit... more ABSTRACT Stability investigations were conducted for a slope at the back of a borax stockpile site near the Bandirma Harbor in the northwestern Turkey. There was a slope failure at the site causing damage in the concrete sections of the harbour in front. Investigations started with deformation monitoring with an inclinometer. Failure mechanisms were determined with back analysis using method of slices and finite difference models. A combined failure mechanism involving a circular failure surface in the slope and a noncircular part in a weak zone under the stockpile area was found to be responsible for the failures in the region.
Uploads
Papers by Levent Tutluoglu