Olgay Yaralı - Academia.edu (original) (raw)

Papers by Olgay Yaralı

Research paper thumbnail of Comparison of Drilling Performance of Chisel and Button Bits on the Electro Hydraulic Driller

Rock Mechanics and Rock Engineering, Dec 27, 2012

Electro hydraulic drillers have been widely used in mining for drilling and roof-bolting. In the ... more Electro hydraulic drillers have been widely used in mining for drilling and roof-bolting. In the drilling process, the performance of the machine is predicted by selecting an appropriate bit type prior to drilling operations. In this paper, a series of field drilling studies were conducted in order to examine and compare the performance of chisel and button bits including wear on the bits. The effects of taper angle on chisel bits, which are at angles of 105°, 110° and 120°, were investigated in terms of rate of penetration, instantaneous drilling rate and specific energy. The results of drilling and abrasivity tests performed in the laboratory supported the outcome of the field studies. Based on laboratory studies and field observations, it was proven that the conglomerate encountered, though it is very abrasive, is easy to drill. The cutter life in the encountered series is also longer in sandstone formation compared to the conglomerate. Additionally, button bits resulted in lower specific energy and higher penetration rates relative to chisel bits, regardless of their taper angles. The results were also supported with statistical analyses.

Research paper thumbnail of Investigation of the rock drilling performance of rotary core drilling

Bulletin of Engineering Geology and the Environment

The specific drilling energy and penetration rate are very important performance parameters for d... more The specific drilling energy and penetration rate are very important performance parameters for drilling. The main objective of this study was to investigate the effect of operational machine parameters and rock properties on drilling performance parameters for rotary core drilling conditions. For this purpose, a rotary core drilling test machine was used to measure drilling performance, taking into account the operational machine parameters (weight on the bit, rotation speed, torque, power of the machine, etc.). The experiments were carried out using 12 different operational conditions, consisting of 3 different rotational speeds (210, 330, and 470 rpm) and 4 different dead loads (50, 70, 90, and 110 kg) on 16 rock samples during the core drilling of rocks with different geological origins, i.e., igneous, sedimentary clastic, and sedimentary carbonated. Subsequently, specific energy values were derived from the experimental values of mechanical and electrical characteristics using relevant empirical models. Among the empirical calculations, the specific energy obtained from the electrical measurements indicates that it is more stable than that of the other empirical approaches. On the other hand, as expected, there is a strong inverse relationship between specific drilling energy and penetration rate. Moreover, regression analysis between the specific energy (470 rpm and 70 kg load) and the properties of the rock samples presents a strong relationship. It is concluded that drilling rate index, Equotip hardness, and applied load are the most influential factors on the drilling performance of rotary drilling. In addition, optimum drilling performance is noted when the penetration rate reaches 1 m/h.

Research paper thumbnail of Matkap Aşınımı ve Ömrü

Research paper thumbnail of Bazi Magmati̇k Kayaçlarin Kayaç Dayanim Katsayisi Ve Schmidt Sertli̇ği̇ Arasindaki̇ İli̇şki̇ler

Bilimsel madencilik dergisi, Jun 1, 2008

Research paper thumbnail of The Effects of Strength Properties of Coal Measures Rocks on Cerchar Abrasivity Index

ÖZ Bu çalışmada, Zonguldak Taşkömür Havzası kömür çevre kayaçlarının dayanımlarının Cerchar aşınm... more ÖZ Bu çalışmada, Zonguldak Taşkömür Havzası kömür çevre kayaçlarının dayanımlarının Cerchar aşınma indeksine (CAI) olan etki-leri araştırılmıştır. Bu amaçla, 29 kömür çevre kayacı üzerinde Cerchar aşınma (CAI), tek eksenli basınç, Brazilian çekme dayanımı deneyleri ile üç eksenli basınç dayanımı deneyleri yapılmıştır. Üç eksenli basınç dayanımı deneylerinden elde edilen sonuçlara göre her bir kaya malzemesinin yenilme zarfları çizilmiştir. ISRM'nin (1983) önerdiği hesaplama yöntemi ile içsel sürtünme açısı (f i) ve görünür kohezyon (c i) değerleri hesaplanmıştır. Daha sonra, CAI ve dayanım deney sonuçları, regresyon analizi ve istatis-tiksel yöntemlerle değerlendirilmiştir. Sonuç olarak, CAI ve tek eksenli basınç dayanımı, Brazilian çekme dayanımı, içsel sürtünme açısı ve görünür kohezyon arasında pozitif doğrusal ilişkiler bulunmuştur. Anahtar Kelimeler: Brazilian çekme dayanımı, Cerchar aşınma indeksi, görünür kohezyon, içsel sürtünme açısı, tek eksenli basınç dayanımı, üç eks...

Research paper thumbnail of Kayaç Özelliklerine Bağlı Olarak Kayaç Delinebilirliğinin Yapay Sinir Ağları (YSA) Metodu İle Tahmini

Bu calismanin amaci; kayac mekanik, indeks ve petrografik ozelliklerinden yararlanarak farkli yap... more Bu calismanin amaci; kayac mekanik, indeks ve petrografik ozelliklerinden yararlanarak farkli yapay sinir aglari (YSA) modellemesi kullanilarak pratik bir delinebilirlik indeks modeli gelistirmektir. Bu amacla, laboratuvarimizda farkli kayaclar uzerinde yapilan DRI test verileri kullanilmistir. Ayrica diger kayac ozellikleri; mekanik (tek eksenli basinc ve Brazilian cekme dayanimi), indeks (Schmidt sertlik ve nokta yuku dayanimi) ve petrografik analiz (ortalama tane boyu, es deger kuvars icerigi (%), cimentolanma derecesi) sonuclari YSA modellemesi icin kullanilmistir. YSA modellemesinde degisken belirlemede, DRI ve diger (aciklayici) degiskenler arasindaki korelasyona bakilmis ve yuksek korelasyona sahip degiskenler YSA’na girdi parametresi olarak secilmistir. Secilen parametrelerden 14 veri agin egitimi icin, 7 veri ise test icin kullanilmis ve en anlamli sonucu veren model belirlenmistir. Testler sonucunda tahmin edilen DRI sonuclari ile deneylerden elde edilen gercek DRI sonucla...

Research paper thumbnail of The effect of mechanical rock properties and brittleness on drillability

Scientific Research and Essays, 2011

This paper examines the relationships between drilling rate index (DRI) and some mechanical prope... more This paper examines the relationships between drilling rate index (DRI) and some mechanical properties of rocks in order to evaluate the effect of properties of strength, indexes, and brittleness of rock on rock drillability. For this purpose, some index properties (Shore scleroscope hardness (SSH), and point load strength (PLS) and geomechanical (uniaxial compressive strength (UCS) and Brazilian tensile strength (BTS)) values of 32 sedimentary, igneous and metamorphic rock samples were determined. Then, the brittleness concepts which use the uniaxial compressive strength and tensile strength of rocks were determined for calculations. Four different brittleness concepts were used in the statistical analysis. In this study, a new brittleness concept (B4) which was found as a result of laboratory studies has proposed by authors for percussive drilling and rotary drilling. The relationships among of DRI and both mechanical rock properties and brittleness concepts were evaluated using r...

Research paper thumbnail of The effects of specimen surface conditions and type of test apparatus on Cerchar Abrasivity Index

Cerchar abrasivity index test (CAI) is widely used for determining the abrasiveness of rocks. Thi... more Cerchar abrasivity index test (CAI) is widely used for determining the abrasiveness of rocks. This test provides an index value that can be used as a gauge for the abrasiveness of rocks in order to estimate bit life and wear in various mining and tunneling applications. CAI studies in different laboratories show some variations in their values depending on the test apparatus (classic, west etc) used and tested specimen surface conditions. In this study, the effects of these factors on CAI were investigated. CAI tests were performed with two different test apparatus both on rough and on saw cut specimen surfaces of 13 different rock samples. This study showed that there have been some differences in the values of CAI between rough and saw cut surfaces. It is founded that rough surface CAI values were generally higher than the saw cut surface CAI values. The statistical analysis in this experiment indicates linear relation between CAI values on rough and saw cut surface and CAI values...

Research paper thumbnail of Investigation of the effect into mechanical properties of rocks on Cerchar abrasivity index

In this study, the relationships between abrasiveness and some mechanical properties of coal meas... more In this study, the relationships between abrasiveness and some mechanical properties of coal measures rocks in Zonguldak Hard Coal Basin were investigated. For this purpose, Cerchar abrasivity (CAI), index (Shore scleroscope hardness, and point load strength) and strength (uniaxial compressive strength and Brazilian tensile strength) tests were carried out on 29 sedimentary rock samples. Then, relationships among CAI and strength, index test values were evaluated using regression analysis and statistical methods. As a result, positive linear relationships were found among CAI and uniaxial compressive strength, Brazilian tensile strength, Shore scleroscope hardness, and axial point load strength.

Research paper thumbnail of Kayaçlar İçin Spesifik Enerji İle Delme Oranı İndeksi (DRI), Mekanik Özellikleri, Cerchar Aşınma İndeksi Arasındaki İlişkilerin İncelenmesi

Bu calismada, 32 farkli kayac (sedimanter, magmatic ve metamorfik) turu uzerinde basit regrasyon ... more Bu calismada, 32 farkli kayac (sedimanter, magmatic ve metamorfik) turu uzerinde basit regrasyon analizi kullanarak delme orani indeks degerleri (DRI) ile mekanik ozellikler (tek eksenli basinc dayanim, dolayli cekme dayanimi), Cerhar asinma indeks degerleri (CAI) ve spesifik enerji (SEcal) arasindaki iliskiler incelenmistir. Kayaclarin mekanik ozellikleri laboratuarda kayaclar uzerinde yapilan deneylerden belirlenmistir. Sievers minyatur delme deneyi ve kirilganlik deneyleri yapilmis ve delme orani indeksi bulunmustur. Ayrica, her bir kayacin spesifik enerji degeri gorgul bir esitlikten hesaplanmistir. Bu calismanin sonucunda da Delme Katsayisi (CD) olarak yeni bir jeoteknik delme indeksi tanimlanmistir. Incelenen buyuklukler (UCS, BTS, CAI, SEcal, CD) birbirleriyle karsilastirilmistir

Research paper thumbnail of Investigation into Relationships Between Cerchar Hardness Index and Some Mechanical Properties of Coal Measure Rocks

Geotechnical and Geological Engineering, 2017

This paper examines the relationships between Cerchar hardness index (CHI) and some mechanical pr... more This paper examines the relationships between Cerchar hardness index (CHI) and some mechanical properties of coal measure rocks in Zonguldak Hard Coal Basin. Some index properties (Cerchar hardness index, Shore scleroscope hardness, in situ Schmidt rebound hardness and point load strength) and strength (uniaxial compressive strength and Brazilian tensile strength) properties of 29 sedimentary rock samples are determined. Then, relationships between (CHI) and strength as well as and some other index values are evaluated using statistical methods. Linear relationships are found between CHI and uniaxial compressive strength, Schmidt rebound hardness. Power relationships are determined between CHI and Shore scleroscope hardness, diametral point load strength, point load strength anisotropy index. Besides, CHI tests are performed by means of bits having tip angles of 99°and 125°and excellent linear relationships are identified between them.

Research paper thumbnail of Kömür Çevre Kayaçları Dayanım Özelliklerinin Cerchar Aşınma İndeksine Olan Etkileri

Yerbilimleri/Hacettepe Üniversitesi Yerbilimleri Uygulama ve Araştırma Merkezi Dergisi, 2016

Bu calismada, Zonguldak Taskomur Havzasi komur cevre kayaclarinin dayanimlarinin Cerchar asinma i... more Bu calismada, Zonguldak Taskomur Havzasi komur cevre kayaclarinin dayanimlarinin Cerchar asinma indeksine (CAI) olan etkileri arastirilmistir. Bu amacla, 29 komur cevre kayaci uzerinde Cerchar asinma (CAI), tek eksenli basinc, Brazilian cekme dayanimi deneyleri ile uc eksenli basinc dayanimi deneyleri yapilmistir. Uc eksenli basinc dayanimi deneylerinden elde edilen sonuclara gore her bir kaya malzemesinin yenilme zarflari cizilmistir. ISRM’nin (1983) onerdigi hesaplama yontemi ile icsel surtunme acisi (fi) ve gorunur kohezyon (ci) degerleri hesaplanmistir. Daha sonra, CAI ve dayanim deney sonuclari, regresyon analizi ve istatistiksel yontemlerle degerlendirilmistir. Sonuc olarak, CAI ve tek eksenli basinc dayanimi, Brazilian cekme dayanimi, icsel surtunme acisi ve gorunur kohezyon arasinda pozitif dogrusal iliskiler bulunmustur.

Research paper thumbnail of Investigation into effect of scratch length and surface condition on Cerchar abrasivity index

Tunnelling and Underground Space Technology, 2016

The Cerchar abrasivity index (CAI) obtained from Cerchar abrasivity tests is an indicator of abra... more The Cerchar abrasivity index (CAI) obtained from Cerchar abrasivity tests is an indicator of abrasiveness of rocks, and widely used for the estimation of bit/cutting tool life and wear rates in various mining and tunnelling applications. The effect of scratch length on CAI is investigated in this study by use of West apparatus and 6 different steel styluses with Rockwell Hardness of HRC40-42, HRC44-46, HRC48-50, HRC50-52, HRC54-56, and HRC58-60. The tests are carried out on 15 different rock samples (sedimentary, igneous, and metamorphic) on which rough and sawn cut surfaces with scratch lengths varying between 2 mm and 20 mm with an increment of 2 mm, thus resulting in total 27,000 scratches. It is observed that the CAI values between 85% and 93% are reached at the sliding distance of 10 mm while about the final CAI value of 99% is reached at 15 mm. It is also observed that the CAI values on rough surfaces are about 18% higher than those on sawn cut surfaces. Besides, it is determined that the most suitable surface condition in CAI test is sawn cut surfaces according to the coefficient of variation of CAI values in measurement depending on the stylus hardness and the measurement surface condition.

Research paper thumbnail of A new approach to rock brittleness and its usability at prediction of drillability

Journal of African Earth Sciences, 2016

Rock brittleness is one of the most important issues in rock drilling and cutting. The relations ... more Rock brittleness is one of the most important issues in rock drilling and cutting. The relations between drillability and brittleness will assist engineers in excavation works. The demand for representative rock parameters related to planning of underground excavations is increasing, as these parameters constitute fundamental input for obtaining the most reliable cost and time estimates. In rock cutting mechanics, the effects of the rock and brittleness on the efficiency of drilling and excavation are examined by many researchers. In this study, 41 different rock types were tested in laboratory to investigate the relations between the drilling rate index and different brittleness values. Firstly, the relations defined in literature are tested. Strength tests are made according to International Society for Rock Mechanics standards. In addition Norwegian University of Science and Technology standards are used to determine drilling rate index. Then, a new brittleness index is proposed which is the arithmetic average of uniaxial compressive strength and tensile strength. Considering the regression analysis carried out, it was seen that the proposed formula showed good correlation for these samples handled in this study. As a result of this study, a high correlation is obtained between the proposed index and drilling rate index values (R:0.84). The results are found to be at least reliable as well as other brittleness equations given in literature.

Research paper thumbnail of Effect of scratch length on the Cerchar abrasivity index

Rock Mechanics for Resources, Energy and Environment, 2013

ISRM International Symposium - EUROCK 2013 -- 23 October 2013 through 26 October 2013 -- -- 13884... more ISRM International Symposium - EUROCK 2013 -- 23 October 2013 through 26 October 2013 -- -- 138846Cerchar Abrasivity Index test (CAI) is widely used for determining the abrasiveness of rocks. This test provides an index value that can be used as a gauge for the abrasiveness of rocks in order to estimation of bit life and wear in various mining and tunneling applications. In this study, changes in CAI with the changes in scratch length were investigated by the use of West apparatus to determine the effects of length on CAI. The tests were carried out on 6 different rock types (3 types of sandstone, limestone, granite and quartzite) where on rough and saw cut surfaces with a scratch length between 2 mm to 20 mm with an increment of 2 mm. It has been found that about 60% of the final Cerchar index (at a 20 mm sliding) was observed at the first 2 mm scratch and continued at a constant rate up to 16–18 mm, then rests around 20 mm sliding distance. This initial high tip wears may partly depend on the deformation and shear failure at the tip of pins. It has been also observed that 87% of the final Cerchar index was reached at 10 mm sliding distance while 97% of the final Cerchar index at the 15 mm sliding distance. Since initial wear at the 2 mm sliding distance is not dependent on the amount of abrasive material in the host rock. Approximately 35% of the Cerchar index can be attributed to the abrasion effect which corresponds to the final 8 mm of sliding distance. However if the sliding distance is increased to 15 mm then 45% of the Cerchar index can be attributed to the rock abrasion effects. This is very important for the tool life estimation in tunneling applications. © 2013 Taylor & Francis Group, London.110M579This study was supported by TUBITAK under the project number of 110M579. The authors also gratefully acknowledge Bülent Ecevit University

Research paper thumbnail of The drillability assessment of rocks using the different brittleness values

Tunnelling and Underground Space Technology, 2011

... Kahraman and Altindag (2004) correlated fracture toughness values with different brittleness ... more ... Kahraman and Altindag (2004) correlated fracture toughness values with different brittleness values using the raw data obtained from the experimental works of two researchers. ... Recently,Yagiz (2009) introduced a new brittleness index obtained from the punch penetration test. ...

Research paper thumbnail of Assessment of relationships between drilling rate index and mechanical properties of rocks

Tunnelling and Underground Space Technology, 2013

This paper examines the relationships between drilling rate index (DRI) and some mechanical prope... more This paper examines the relationships between drilling rate index (DRI) and some mechanical properties of rocks in order to evaluate the effect of strength and indexes of rock on rock drillability. For this purpose, some index properties (in situ Schmidt rebound hardness (SRH), Shore scleroscope hardness (SSH), and point load strength (PLS)) and strength properties (uniaxial compressive strength (UCS) and Brazilian tensile strength (BTS)) values of 32 sedimentary, igneous and metamorphic rock samples were determined. The relationships between DRI and both strength and indexes properties were evaluated using regression analysis and statistical methods. As a result, decreasing linear relationships were found between DRI and uniaxial compressive strength, Schmidt rebound hardness, Shore scleroscope hardness, diametral and axial point load strength.

Research paper thumbnail of Comparison of Drilling Performance of Chisel and Button Bits on the Electro Hydraulic Driller

Rock Mechanics and Rock Engineering, 2012

Electro hydraulic drillers have been widely used in mining for drilling and roof-bolting. In the ... more Electro hydraulic drillers have been widely used in mining for drilling and roof-bolting. In the drilling process, the performance of the machine is predicted by selecting an appropriate bit type prior to drilling operations. In this paper, a series of field drilling studies were conducted in order to examine and compare the performance of chisel and button bits including wear on the bits. The effects of taper angle on chisel bits, which are at angles of 105°, 110° and 120°, were investigated in terms of rate of penetration, instantaneous drilling rate and specific energy. The results of drilling and abrasivity tests performed in the laboratory supported the outcome of the field studies. Based on laboratory studies and field observations, it was proven that the conglomerate encountered, though it is very abrasive, is easy to drill. The cutter life in the encountered series is also longer in sandstone formation compared to the conglomerate. Additionally, button bits resulted in lower specific energy and higher penetration rates relative to chisel bits, regardless of their taper angles. The results were also supported with statistical analyses.

Research paper thumbnail of ISRM Suggested Method for Determining the Abrasivity of Rock by the CERCHAR Abrasivity Test

Rock Mechanics and Rock Engineering, 2013

Research paper thumbnail of A study of rock abrasivity and tool wear in Coal Measures Rocks

International Journal of Coal Geology, 2008

This paper examines the relations between Cerchar abrasivity index (CAI) and petrographic propert... more This paper examines the relations between Cerchar abrasivity index (CAI) and petrographic properties of Coal Measures Rocks in the Zonguldak Coal Basin, Turkey. In this study, petrographic properties and abrasivity indices of 29 sedimentary rock samples were determined and the values of CAI and petrographic analysis results were compared. A good linear relationship between CAI and average quartz grain size

Research paper thumbnail of Comparison of Drilling Performance of Chisel and Button Bits on the Electro Hydraulic Driller

Rock Mechanics and Rock Engineering, Dec 27, 2012

Electro hydraulic drillers have been widely used in mining for drilling and roof-bolting. In the ... more Electro hydraulic drillers have been widely used in mining for drilling and roof-bolting. In the drilling process, the performance of the machine is predicted by selecting an appropriate bit type prior to drilling operations. In this paper, a series of field drilling studies were conducted in order to examine and compare the performance of chisel and button bits including wear on the bits. The effects of taper angle on chisel bits, which are at angles of 105°, 110° and 120°, were investigated in terms of rate of penetration, instantaneous drilling rate and specific energy. The results of drilling and abrasivity tests performed in the laboratory supported the outcome of the field studies. Based on laboratory studies and field observations, it was proven that the conglomerate encountered, though it is very abrasive, is easy to drill. The cutter life in the encountered series is also longer in sandstone formation compared to the conglomerate. Additionally, button bits resulted in lower specific energy and higher penetration rates relative to chisel bits, regardless of their taper angles. The results were also supported with statistical analyses.

Research paper thumbnail of Investigation of the rock drilling performance of rotary core drilling

Bulletin of Engineering Geology and the Environment

The specific drilling energy and penetration rate are very important performance parameters for d... more The specific drilling energy and penetration rate are very important performance parameters for drilling. The main objective of this study was to investigate the effect of operational machine parameters and rock properties on drilling performance parameters for rotary core drilling conditions. For this purpose, a rotary core drilling test machine was used to measure drilling performance, taking into account the operational machine parameters (weight on the bit, rotation speed, torque, power of the machine, etc.). The experiments were carried out using 12 different operational conditions, consisting of 3 different rotational speeds (210, 330, and 470 rpm) and 4 different dead loads (50, 70, 90, and 110 kg) on 16 rock samples during the core drilling of rocks with different geological origins, i.e., igneous, sedimentary clastic, and sedimentary carbonated. Subsequently, specific energy values were derived from the experimental values of mechanical and electrical characteristics using relevant empirical models. Among the empirical calculations, the specific energy obtained from the electrical measurements indicates that it is more stable than that of the other empirical approaches. On the other hand, as expected, there is a strong inverse relationship between specific drilling energy and penetration rate. Moreover, regression analysis between the specific energy (470 rpm and 70 kg load) and the properties of the rock samples presents a strong relationship. It is concluded that drilling rate index, Equotip hardness, and applied load are the most influential factors on the drilling performance of rotary drilling. In addition, optimum drilling performance is noted when the penetration rate reaches 1 m/h.

Research paper thumbnail of Matkap Aşınımı ve Ömrü

Research paper thumbnail of Bazi Magmati̇k Kayaçlarin Kayaç Dayanim Katsayisi Ve Schmidt Sertli̇ği̇ Arasindaki̇ İli̇şki̇ler

Bilimsel madencilik dergisi, Jun 1, 2008

Research paper thumbnail of The Effects of Strength Properties of Coal Measures Rocks on Cerchar Abrasivity Index

ÖZ Bu çalışmada, Zonguldak Taşkömür Havzası kömür çevre kayaçlarının dayanımlarının Cerchar aşınm... more ÖZ Bu çalışmada, Zonguldak Taşkömür Havzası kömür çevre kayaçlarının dayanımlarının Cerchar aşınma indeksine (CAI) olan etki-leri araştırılmıştır. Bu amaçla, 29 kömür çevre kayacı üzerinde Cerchar aşınma (CAI), tek eksenli basınç, Brazilian çekme dayanımı deneyleri ile üç eksenli basınç dayanımı deneyleri yapılmıştır. Üç eksenli basınç dayanımı deneylerinden elde edilen sonuçlara göre her bir kaya malzemesinin yenilme zarfları çizilmiştir. ISRM'nin (1983) önerdiği hesaplama yöntemi ile içsel sürtünme açısı (f i) ve görünür kohezyon (c i) değerleri hesaplanmıştır. Daha sonra, CAI ve dayanım deney sonuçları, regresyon analizi ve istatis-tiksel yöntemlerle değerlendirilmiştir. Sonuç olarak, CAI ve tek eksenli basınç dayanımı, Brazilian çekme dayanımı, içsel sürtünme açısı ve görünür kohezyon arasında pozitif doğrusal ilişkiler bulunmuştur. Anahtar Kelimeler: Brazilian çekme dayanımı, Cerchar aşınma indeksi, görünür kohezyon, içsel sürtünme açısı, tek eksenli basınç dayanımı, üç eks...

Research paper thumbnail of Kayaç Özelliklerine Bağlı Olarak Kayaç Delinebilirliğinin Yapay Sinir Ağları (YSA) Metodu İle Tahmini

Bu calismanin amaci; kayac mekanik, indeks ve petrografik ozelliklerinden yararlanarak farkli yap... more Bu calismanin amaci; kayac mekanik, indeks ve petrografik ozelliklerinden yararlanarak farkli yapay sinir aglari (YSA) modellemesi kullanilarak pratik bir delinebilirlik indeks modeli gelistirmektir. Bu amacla, laboratuvarimizda farkli kayaclar uzerinde yapilan DRI test verileri kullanilmistir. Ayrica diger kayac ozellikleri; mekanik (tek eksenli basinc ve Brazilian cekme dayanimi), indeks (Schmidt sertlik ve nokta yuku dayanimi) ve petrografik analiz (ortalama tane boyu, es deger kuvars icerigi (%), cimentolanma derecesi) sonuclari YSA modellemesi icin kullanilmistir. YSA modellemesinde degisken belirlemede, DRI ve diger (aciklayici) degiskenler arasindaki korelasyona bakilmis ve yuksek korelasyona sahip degiskenler YSA’na girdi parametresi olarak secilmistir. Secilen parametrelerden 14 veri agin egitimi icin, 7 veri ise test icin kullanilmis ve en anlamli sonucu veren model belirlenmistir. Testler sonucunda tahmin edilen DRI sonuclari ile deneylerden elde edilen gercek DRI sonucla...

Research paper thumbnail of The effect of mechanical rock properties and brittleness on drillability

Scientific Research and Essays, 2011

This paper examines the relationships between drilling rate index (DRI) and some mechanical prope... more This paper examines the relationships between drilling rate index (DRI) and some mechanical properties of rocks in order to evaluate the effect of properties of strength, indexes, and brittleness of rock on rock drillability. For this purpose, some index properties (Shore scleroscope hardness (SSH), and point load strength (PLS) and geomechanical (uniaxial compressive strength (UCS) and Brazilian tensile strength (BTS)) values of 32 sedimentary, igneous and metamorphic rock samples were determined. Then, the brittleness concepts which use the uniaxial compressive strength and tensile strength of rocks were determined for calculations. Four different brittleness concepts were used in the statistical analysis. In this study, a new brittleness concept (B4) which was found as a result of laboratory studies has proposed by authors for percussive drilling and rotary drilling. The relationships among of DRI and both mechanical rock properties and brittleness concepts were evaluated using r...

Research paper thumbnail of The effects of specimen surface conditions and type of test apparatus on Cerchar Abrasivity Index

Cerchar abrasivity index test (CAI) is widely used for determining the abrasiveness of rocks. Thi... more Cerchar abrasivity index test (CAI) is widely used for determining the abrasiveness of rocks. This test provides an index value that can be used as a gauge for the abrasiveness of rocks in order to estimate bit life and wear in various mining and tunneling applications. CAI studies in different laboratories show some variations in their values depending on the test apparatus (classic, west etc) used and tested specimen surface conditions. In this study, the effects of these factors on CAI were investigated. CAI tests were performed with two different test apparatus both on rough and on saw cut specimen surfaces of 13 different rock samples. This study showed that there have been some differences in the values of CAI between rough and saw cut surfaces. It is founded that rough surface CAI values were generally higher than the saw cut surface CAI values. The statistical analysis in this experiment indicates linear relation between CAI values on rough and saw cut surface and CAI values...

Research paper thumbnail of Investigation of the effect into mechanical properties of rocks on Cerchar abrasivity index

In this study, the relationships between abrasiveness and some mechanical properties of coal meas... more In this study, the relationships between abrasiveness and some mechanical properties of coal measures rocks in Zonguldak Hard Coal Basin were investigated. For this purpose, Cerchar abrasivity (CAI), index (Shore scleroscope hardness, and point load strength) and strength (uniaxial compressive strength and Brazilian tensile strength) tests were carried out on 29 sedimentary rock samples. Then, relationships among CAI and strength, index test values were evaluated using regression analysis and statistical methods. As a result, positive linear relationships were found among CAI and uniaxial compressive strength, Brazilian tensile strength, Shore scleroscope hardness, and axial point load strength.

Research paper thumbnail of Kayaçlar İçin Spesifik Enerji İle Delme Oranı İndeksi (DRI), Mekanik Özellikleri, Cerchar Aşınma İndeksi Arasındaki İlişkilerin İncelenmesi

Bu calismada, 32 farkli kayac (sedimanter, magmatic ve metamorfik) turu uzerinde basit regrasyon ... more Bu calismada, 32 farkli kayac (sedimanter, magmatic ve metamorfik) turu uzerinde basit regrasyon analizi kullanarak delme orani indeks degerleri (DRI) ile mekanik ozellikler (tek eksenli basinc dayanim, dolayli cekme dayanimi), Cerhar asinma indeks degerleri (CAI) ve spesifik enerji (SEcal) arasindaki iliskiler incelenmistir. Kayaclarin mekanik ozellikleri laboratuarda kayaclar uzerinde yapilan deneylerden belirlenmistir. Sievers minyatur delme deneyi ve kirilganlik deneyleri yapilmis ve delme orani indeksi bulunmustur. Ayrica, her bir kayacin spesifik enerji degeri gorgul bir esitlikten hesaplanmistir. Bu calismanin sonucunda da Delme Katsayisi (CD) olarak yeni bir jeoteknik delme indeksi tanimlanmistir. Incelenen buyuklukler (UCS, BTS, CAI, SEcal, CD) birbirleriyle karsilastirilmistir

Research paper thumbnail of Investigation into Relationships Between Cerchar Hardness Index and Some Mechanical Properties of Coal Measure Rocks

Geotechnical and Geological Engineering, 2017

This paper examines the relationships between Cerchar hardness index (CHI) and some mechanical pr... more This paper examines the relationships between Cerchar hardness index (CHI) and some mechanical properties of coal measure rocks in Zonguldak Hard Coal Basin. Some index properties (Cerchar hardness index, Shore scleroscope hardness, in situ Schmidt rebound hardness and point load strength) and strength (uniaxial compressive strength and Brazilian tensile strength) properties of 29 sedimentary rock samples are determined. Then, relationships between (CHI) and strength as well as and some other index values are evaluated using statistical methods. Linear relationships are found between CHI and uniaxial compressive strength, Schmidt rebound hardness. Power relationships are determined between CHI and Shore scleroscope hardness, diametral point load strength, point load strength anisotropy index. Besides, CHI tests are performed by means of bits having tip angles of 99°and 125°and excellent linear relationships are identified between them.

Research paper thumbnail of Kömür Çevre Kayaçları Dayanım Özelliklerinin Cerchar Aşınma İndeksine Olan Etkileri

Yerbilimleri/Hacettepe Üniversitesi Yerbilimleri Uygulama ve Araştırma Merkezi Dergisi, 2016

Bu calismada, Zonguldak Taskomur Havzasi komur cevre kayaclarinin dayanimlarinin Cerchar asinma i... more Bu calismada, Zonguldak Taskomur Havzasi komur cevre kayaclarinin dayanimlarinin Cerchar asinma indeksine (CAI) olan etkileri arastirilmistir. Bu amacla, 29 komur cevre kayaci uzerinde Cerchar asinma (CAI), tek eksenli basinc, Brazilian cekme dayanimi deneyleri ile uc eksenli basinc dayanimi deneyleri yapilmistir. Uc eksenli basinc dayanimi deneylerinden elde edilen sonuclara gore her bir kaya malzemesinin yenilme zarflari cizilmistir. ISRM’nin (1983) onerdigi hesaplama yontemi ile icsel surtunme acisi (fi) ve gorunur kohezyon (ci) degerleri hesaplanmistir. Daha sonra, CAI ve dayanim deney sonuclari, regresyon analizi ve istatistiksel yontemlerle degerlendirilmistir. Sonuc olarak, CAI ve tek eksenli basinc dayanimi, Brazilian cekme dayanimi, icsel surtunme acisi ve gorunur kohezyon arasinda pozitif dogrusal iliskiler bulunmustur.

Research paper thumbnail of Investigation into effect of scratch length and surface condition on Cerchar abrasivity index

Tunnelling and Underground Space Technology, 2016

The Cerchar abrasivity index (CAI) obtained from Cerchar abrasivity tests is an indicator of abra... more The Cerchar abrasivity index (CAI) obtained from Cerchar abrasivity tests is an indicator of abrasiveness of rocks, and widely used for the estimation of bit/cutting tool life and wear rates in various mining and tunnelling applications. The effect of scratch length on CAI is investigated in this study by use of West apparatus and 6 different steel styluses with Rockwell Hardness of HRC40-42, HRC44-46, HRC48-50, HRC50-52, HRC54-56, and HRC58-60. The tests are carried out on 15 different rock samples (sedimentary, igneous, and metamorphic) on which rough and sawn cut surfaces with scratch lengths varying between 2 mm and 20 mm with an increment of 2 mm, thus resulting in total 27,000 scratches. It is observed that the CAI values between 85% and 93% are reached at the sliding distance of 10 mm while about the final CAI value of 99% is reached at 15 mm. It is also observed that the CAI values on rough surfaces are about 18% higher than those on sawn cut surfaces. Besides, it is determined that the most suitable surface condition in CAI test is sawn cut surfaces according to the coefficient of variation of CAI values in measurement depending on the stylus hardness and the measurement surface condition.

Research paper thumbnail of A new approach to rock brittleness and its usability at prediction of drillability

Journal of African Earth Sciences, 2016

Rock brittleness is one of the most important issues in rock drilling and cutting. The relations ... more Rock brittleness is one of the most important issues in rock drilling and cutting. The relations between drillability and brittleness will assist engineers in excavation works. The demand for representative rock parameters related to planning of underground excavations is increasing, as these parameters constitute fundamental input for obtaining the most reliable cost and time estimates. In rock cutting mechanics, the effects of the rock and brittleness on the efficiency of drilling and excavation are examined by many researchers. In this study, 41 different rock types were tested in laboratory to investigate the relations between the drilling rate index and different brittleness values. Firstly, the relations defined in literature are tested. Strength tests are made according to International Society for Rock Mechanics standards. In addition Norwegian University of Science and Technology standards are used to determine drilling rate index. Then, a new brittleness index is proposed which is the arithmetic average of uniaxial compressive strength and tensile strength. Considering the regression analysis carried out, it was seen that the proposed formula showed good correlation for these samples handled in this study. As a result of this study, a high correlation is obtained between the proposed index and drilling rate index values (R:0.84). The results are found to be at least reliable as well as other brittleness equations given in literature.

Research paper thumbnail of Effect of scratch length on the Cerchar abrasivity index

Rock Mechanics for Resources, Energy and Environment, 2013

ISRM International Symposium - EUROCK 2013 -- 23 October 2013 through 26 October 2013 -- -- 13884... more ISRM International Symposium - EUROCK 2013 -- 23 October 2013 through 26 October 2013 -- -- 138846Cerchar Abrasivity Index test (CAI) is widely used for determining the abrasiveness of rocks. This test provides an index value that can be used as a gauge for the abrasiveness of rocks in order to estimation of bit life and wear in various mining and tunneling applications. In this study, changes in CAI with the changes in scratch length were investigated by the use of West apparatus to determine the effects of length on CAI. The tests were carried out on 6 different rock types (3 types of sandstone, limestone, granite and quartzite) where on rough and saw cut surfaces with a scratch length between 2 mm to 20 mm with an increment of 2 mm. It has been found that about 60% of the final Cerchar index (at a 20 mm sliding) was observed at the first 2 mm scratch and continued at a constant rate up to 16–18 mm, then rests around 20 mm sliding distance. This initial high tip wears may partly depend on the deformation and shear failure at the tip of pins. It has been also observed that 87% of the final Cerchar index was reached at 10 mm sliding distance while 97% of the final Cerchar index at the 15 mm sliding distance. Since initial wear at the 2 mm sliding distance is not dependent on the amount of abrasive material in the host rock. Approximately 35% of the Cerchar index can be attributed to the abrasion effect which corresponds to the final 8 mm of sliding distance. However if the sliding distance is increased to 15 mm then 45% of the Cerchar index can be attributed to the rock abrasion effects. This is very important for the tool life estimation in tunneling applications. © 2013 Taylor & Francis Group, London.110M579This study was supported by TUBITAK under the project number of 110M579. The authors also gratefully acknowledge Bülent Ecevit University

Research paper thumbnail of The drillability assessment of rocks using the different brittleness values

Tunnelling and Underground Space Technology, 2011

... Kahraman and Altindag (2004) correlated fracture toughness values with different brittleness ... more ... Kahraman and Altindag (2004) correlated fracture toughness values with different brittleness values using the raw data obtained from the experimental works of two researchers. ... Recently,Yagiz (2009) introduced a new brittleness index obtained from the punch penetration test. ...

Research paper thumbnail of Assessment of relationships between drilling rate index and mechanical properties of rocks

Tunnelling and Underground Space Technology, 2013

This paper examines the relationships between drilling rate index (DRI) and some mechanical prope... more This paper examines the relationships between drilling rate index (DRI) and some mechanical properties of rocks in order to evaluate the effect of strength and indexes of rock on rock drillability. For this purpose, some index properties (in situ Schmidt rebound hardness (SRH), Shore scleroscope hardness (SSH), and point load strength (PLS)) and strength properties (uniaxial compressive strength (UCS) and Brazilian tensile strength (BTS)) values of 32 sedimentary, igneous and metamorphic rock samples were determined. The relationships between DRI and both strength and indexes properties were evaluated using regression analysis and statistical methods. As a result, decreasing linear relationships were found between DRI and uniaxial compressive strength, Schmidt rebound hardness, Shore scleroscope hardness, diametral and axial point load strength.

Research paper thumbnail of Comparison of Drilling Performance of Chisel and Button Bits on the Electro Hydraulic Driller

Rock Mechanics and Rock Engineering, 2012

Electro hydraulic drillers have been widely used in mining for drilling and roof-bolting. In the ... more Electro hydraulic drillers have been widely used in mining for drilling and roof-bolting. In the drilling process, the performance of the machine is predicted by selecting an appropriate bit type prior to drilling operations. In this paper, a series of field drilling studies were conducted in order to examine and compare the performance of chisel and button bits including wear on the bits. The effects of taper angle on chisel bits, which are at angles of 105°, 110° and 120°, were investigated in terms of rate of penetration, instantaneous drilling rate and specific energy. The results of drilling and abrasivity tests performed in the laboratory supported the outcome of the field studies. Based on laboratory studies and field observations, it was proven that the conglomerate encountered, though it is very abrasive, is easy to drill. The cutter life in the encountered series is also longer in sandstone formation compared to the conglomerate. Additionally, button bits resulted in lower specific energy and higher penetration rates relative to chisel bits, regardless of their taper angles. The results were also supported with statistical analyses.

Research paper thumbnail of ISRM Suggested Method for Determining the Abrasivity of Rock by the CERCHAR Abrasivity Test

Rock Mechanics and Rock Engineering, 2013

Research paper thumbnail of A study of rock abrasivity and tool wear in Coal Measures Rocks

International Journal of Coal Geology, 2008

This paper examines the relations between Cerchar abrasivity index (CAI) and petrographic propert... more This paper examines the relations between Cerchar abrasivity index (CAI) and petrographic properties of Coal Measures Rocks in the Zonguldak Coal Basin, Turkey. In this study, petrographic properties and abrasivity indices of 29 sedimentary rock samples were determined and the values of CAI and petrographic analysis results were compared. A good linear relationship between CAI and average quartz grain size