Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleAçık Erişim2025Re-evaluation of excavation class limits for underground excavations based on new data
Gurocak, Zulfu; Kaya, Ayberk; Kanik, Mustafa; Alemdag, Selcuk
Many researchers have proposed empirical excavatability classifications to easily and quickly assess rock masses. These classifications mostly apply to surface excavations, while those for underground excavations are limited. Updating the classifications proposed for underground excavations based on new data is important in terms of eliminating the deficiencies in this regard. This study determined the engineering properties (RMR, Q, GSI), rock material strengths, and in-situ excavation classes of 16 underground rock masses. The new data were compared with excavation classifications from various researchers and empirical classes. The study found that empirical classifications for surface conditions are not applicable for underground. Excavation is more challenging in underground conditions due to stress from overburden. While excavation classes align for good to very good rock masses in both conditions, there is no perfect match for medium, weak, and very weak rock masses for underground. The study suggests that for underground excavation classes (blasting, hammer&blasting, hammer, and digging), both RMR89 and Q values should be used together to differentiate between classes. When using GSI for classification, the Is(50) value of the rock material should also be considered. The σcm parameter is the most critical in evaluating rock mass excavatability.
- MakaleYalnız künye2021The effects of freeze-thaw cycles and block size on the use of the Gümüşhane Granitoid (Gümüşhane/Turkey) as building stone
Dağ, Serhat; Alemdağ, Selçuk; Kaya, Ayberk
The present study aims to examine the usability of the Gümüşhane Granitoid as a building stone taking into consideration the short-term freeze-thaw cycles and mean block volume. A total of 180 specimens were used in the study prepared from the block samples compiled from 10 different areas in the Gümüşhane (NE Turkey) provincial borders. Mean block volume was calculated about 8 dm3 during the discontinuity studies carried out on the Gümüşhane Granitoid; as a result of which, it was determined that the granitoids are suited for obtaining blocks. The annual freeze-thaw cycle map of Turkey was used for determining the number of freeze-thaw cycles to be applied on the rocks in addition to taking into account the weathering of monzogranites. A total of 25 freeze-thaw cycle tests were applied on the rocks with experimental studies repeated at every 5 cycles. It was determined following the freeze-thaw tests that significant changes have occurred especially in the strength and water absorption parameters of the monzogranites and that they have been affected negatively. This indicates that the monzogranites are not suited for outdoor use as building stone in regions such as the Gümüşhane province and regions with similar climate characteristics, but that they can be used in a lot of regions with more moderate climates. As a building stone, monzogranites can be used either as cobblestone, curbstone, or paving stone subject to their mean block volume. It is considered that the widespread of the Gümüşhane Granitoid may provide a substantial economical income to the country.
- MakaleYalnız künye20202D and 3D numerical simulations of a reinforced landslide: A case study in NE Turkey
Ersoy, Hakan; Kaya, Ayberk; Angın, Zekaİ; DaĞ, Serhat
The purpose of this study is to investigate the slope stability problem that occurred in the Ulubey (NE Turkey) during the construction of a hospital building and to propose a reliable support design. The borehole applications, geophysical surveys, groundwater measurements, soil sampling and SPT were performed to establish the geotechnical model. Based on the site characterization investigations, three units were defined as sliding material, residual regolith and volcanic rocks. Strength parameters of the sliding and residual soil materials were obtained from the back analysis. The long-term performance of the double row-bore piles was proposed as support measures and was controlled using the limit equilibrium (LE) and finite element (FEM) analyses methods under a dynamic condition. The 2D-LE and 2D-FEM analysis results showed that the suggested support design is reliable for long-term stability. The locations of the critical shear surface determined by 2D methods were almost the same as those obtained from 3D-FEM method and the total displacement values obtained from the 3D-FEM model were smaller than those obtained from the 2D-FEM model. These results indicated that 2D and 3D stability analyses were sufficient to evaluate the stability of uncomplex slope geometry when a reliable design with simple solutions was required.
- MakaleYalnız künye2020Medium scale earthflow susceptibility modelling by remote sensing and geographical information systems based multivariate statistics approach: an example from Northeastern Turkey
Dağ, Serhat; Akgün, Aykut; Kaya, Ayberk; Alemdağ, Selçuk; Bostancı, Hasan Tahsin
The aim of the present study was to produce an earthflow susceptibility map for the city center and environs of the province of Rize located at the Northeastern part of Turkey. The study area is the rainiest region of Turkey, and due to the triggering effect of precipitation earthflows are frequently observed in and around the study area. Besides this point, weathered rock units and steep topography accompany with precipitation for the occurrence of earthflow cases. Considering this point, an earthflow susceptibility mapping was inferred to be a necessity for the area. Parameters, such as lithology, slope gradient, slope aspect, topographical wetness index (TWI), stream power index (SPI), slope curvature, and sediment capacity index (LS) were considered to be earthflow conditioning parameters. A multi-temporal earthflow inventory map for a period of 4 years (2011–2015) was initially generated by way of remote sensing approach and field surveys. Earthflow susceptibility map was produced using the logistic regression method after which the produced susceptibility map was validated. The mapped earthflows were separated into two groups prior to modelling and validation. The first group was for training and the second group was for validation steps. The accuracy of the model was measured by fitting them to a validation set of mapped earthflows. Area under curvature (AUC) approach was applied for validation purposes. The prediction capability of the earthflow susceptibility map produced can be regarded as acceptable in accordance with the AUC values of 0.62 for the logistic regression model. Based on these results, the obtained earthflow susceptibility map can be used to mitigate hazards related to landslides and to aid in land-use planning for the Rize city center.
- MakaleAçık Erişim2018Gündoğan (Ardeşen-Rize) Köyü Yerleşim Alanındaki Yamaç Duraysızlığının Jeoteknik Açıdan İncelenmesi
Dağ, Serhat; Kaya, Ayberk; Demirbaş, Cem
Bu çalışma kapsamında Gündoğan (Ardeşen-Rize) Köyü yerleşim alanının üstünde bulunduğu yamaçta meydana gelen ve yaklaşık olarak 2.24 hektarlık bir alanı kapsayan duraysızlık problemi jeoteknik açıdan incelenmiştir. Yapılan çalışmalar sırasıyla arazi, laboratuvar ve şev duraylılık analizi çalışmaları olmak üzere üç aşamada yürütülmüştür. Bu amaçla eğim yönünde 3 hat boyunca toplam 150 m derinliğinde 6 adet sondaj kuyusu açılmış, 3 profilde jeofizik çalışmalar gerçekleştirilmiş ve 2 sondaj kuyusunda inklinometre ölçümleri yapılmıştır. Arazi çalışmaları sonucunda ana kayayı Geç Kretase yaşlı Çağlayan Formasyonu’na ait volkano- tortul kayaçların oluşturduğu ve bu birimlerin üzerine kalınlığı 5.0-16.5 m arasında değişen yamaç molozunun geldiği belirlenmiştir. Yamaç molozunun fiziko-mekanik özelliklerini tespit etmek için araştırma sondajlarından örselenmemiş örnekler alınmıştır. Arazi ve laboratuvar çalışmalarından elde edilen veriler yardımıyla Limit Denge ve sonlu elemanlar tabanlı Kayma Dayanımı Azaltma Yaklaşımı (FEM-SSR) yöntemleri kullanılarak duraylılık analizleri yapılmış ve sonuçlar karşılaştırılmıştır. Duraylılık analizleriyle belirlenen kayma yüzeylerinin dağılımları incelendiğinde yamaçta önlem alınmaması durumunda yenilmenin gerileyen şekilde devam edebileceği saptanmıştır. Yapılan inklinometre ölçümleri ve duraylılık analizleri, Gündoğan Köyü yerleşim alanındaki yamaç molozunun duraysız olduğunu ve heyelan potansiyeli taşıdığını göstermektedir.
- MakaleYalnız künye2018Bearing capacity and slope stability assessment of rock masses at the Subasi viaduct site, NE, Turkey
Kaya, Ayberk; Bulut, Fikri; Dağ, Serhat
This study investigates the bearing capacity of rock masses and stability of slopes at the Subasi viaduct site which is a part of the improvement project of the Artvin–Hopa government highway between KM 6 + 500 and 13 + 787 in NE Turkey. The geotechnical studies were performed in three stages. Firstly, the bearing capacity of moderately weathered andesitic tuff was evaluated using the empirical equations. Secondly, the major principal stress and vertical displacement due to the viaduct and traffic loadings at the level of foundations were determined by the finite element method (FEM). The vertical displacement value and comparison of bearing capacity and major principal stress show that any problem is not expected at the viaduct site in terms of the bearing capacity. Finally, the stability of slopes at the viaduct site was investigated using kinematic, limit equilibrium, and finite element method-based shear strength reduction analyses methods. It was concluded that no discontinuity controlled failures at the slopes are expected. However, a circular failure is possible to occur at the face slope excavated in highly weathered andesitic tuff. After support application, the long-term stabilization of face slope has been achieved. Consequently, it is suggested that the empirical, analytical, and numerical methods should be combined for a more reliable construction design.
- MakaleAçık Erişim2016Stability assessment of high-steep cut slope debris on a landslide (Gumushane, NE Turkey)
Kaya, Ayberk; Alemdağ, Selçuk; Dağ, Serhat; Gürocak, Zülfü
The objective of this study was to examine the effects on the stability of slope debris of planned slope excavations around the vicinity of Gumushane Imam-Hatip High School in NE Turkey. To assess the geotechnical properties of slope debris along the determined cross-sections, four exploration boreholes with a total length of 100 m were drilled and undisturbed soil samples were collected. Slope debris is composed of two soil zones and its depth varies between 15 m and 21 m. It was determined from the experimental results that the soil class of the upper zone is CL (low plasticity clay) and CH (high plasticity clay) whereas the soil class of the lower zone is SC (clayey sand) and GC (clayey gravel). Peak cohesions of the upper and lower zones were 26.3 kPa and 10.2 kPa, and their peak internal friction angles were 16° and 24°, respectively. Limit equilibrium (LE) analyses for the slopes were evaluated using Slide v5.0 software for the pre-excavation, post-excavation, and supported cases. The results of LE analyses showed the existence of a landslide along the SW direction; the landslide would extend to cover the whole region if the excavation were to be performed without applying engineering measures. Finally, the precautions to be taken were determined and stability analyses for the supported case were evaluated. These analyses showed that the active lateral forces applied by the proposed retaining walls to the cut slope should be 8325 and 3103 kN, respectively.
- MakaleAçık Erişim2015Utilization of the limit equilibrium and finite element methods for the stability analysis of the slope debris: An example of the Kalebasi District (NE Turkey)
Alemdag, Selcuk; Kaya, Ayberk; Karadag, Mustafa; Gurocak, Zulfu; Bulut, Fikri
The stability of the slope debris in residential area of the Kalebasi District (Ozkurtun-Gumushane) was investigated using the Limit Equilibrium (LE) and Finite Element Shear-Strength Reduction (FE-SSR) methods. Along the survey lines, four trial pits were dug and fourteen boreholes having a total length of 345m were drilled. Also, seismic refraction studies were conducted along the five lines. According to the field studies, thickness of the slope debris covering the 98ha of the study area varies between 1 and 36m. To determine the physical and shear strength properties of the slope debris, undisturbed samples were taken from the trial pits. As a result of the laboratory tests, soil categories of the debris were found to be as Clayey Sand (SC), Silty Sand (SM) and Low Plasticity Clay (CL). The deformation-controlled shear box tests were carried out to determine the shear strength parameters of the slope debris. According to these tests it was found that the peak cohesion and peak friction angle varies between 2.63-16.35kN/m2 and 20-27°, respectively. Stability analyses were performed using the obtained data from field and laboratory investigations in the Slide v5.0 and Phase2 v6.0 software programs and results were compared. In LE stability analyses, the factor of safety (FOS) of survey lines were found to be as 1.44, 1.80, 1.96, and 1.72; however for the FE-SSR method they were determined as 1.39, 1.72, 1.59, and 1.58, respectively.
- MakaleYalnız künye2011Doğal taş ocaklarında blok hacminin belirlenmesi için RQD ve Jᵥ’nin kullanılabilirliği
Yilmaz, Ali Osman; Çapik, Mehmet; Kaya, Ayberk; Alemdag, Selcuk
Bu çalışmada, Doğankent (Giresun) yöresinde yüzeylenen Harşit Granitoyidi’nden üretilebilecek blokların hacminin belirlenmesinde, Kaya Kalite Göstergesi (RQD) ve Hacimsel Eklem Sayısı (J ᵥ) parametrelerinin kullanılabilirliği araştırılmıştır. Bu amaçla, pilot çalışma alanı olarak bir ocak seçilmiş ve açılan şevlerde hat etüdü çalışmaları yapılarak, süreksizliklerin özellikleri tayin edilmiştir. Harşit Granitoyidi’nden elde edilebilecek Blok Hacminin belirlenmesinde Kaya Kütle İndeksi (RMi) sınıflama sisteminde girdi parametresi olan blok hacmi (Vb) kullanılmıştır. Vb değerinin belirlenmesinde kullanılan Jv ve RQD değişkenleri ocak içindeki farklı şevlerde yapılan süreksizlikler arası ölçümler ile belirlenmiştir. RMi sınıflamasında kullanılan Blok Şekli Faktörüne (β) göre yapılan değerlendirmede blokların genellikle “kompakt, hafifçe uzun-düz” şekilli olduğu tesbit edilmiştir. Blok hacminin belirlenmesinde kullanılan parametrelerden RQD değişkeninin sınırlamalar içermesi nedeniyle, blok hacminin hesaplanmasında J ᵥ değerlerinin kullanılması tercih edilmiştir. Yapılan değerlendirmeler sonucunda Harşit Granitoyidi’nden üretilecek blokların ortalama hacminin Vb= 7.15 m³ olduğu belirlenmiş olup, bu değer ticari olarak değerlendirilebilecek blok hacmi aralığındadır.
- MakaleYalnız künye2011Farklı ayrışma derecesine sahip kaya kütlelerinin kazılabilirlik özellikleri: Gümüşhane Granitoyidi örneği, Gümüşhane, KD Türkiye
Dağ, Serhat; Kaya, Ayberk; Gurocak, Zulfu; Alemdag, Selcuk
Kayaların kazılabilirlik özelliklerini belirlemek amacıyla yapılacak çalışmalar kazı maliyeti açısından mühendislik projelerinin uygulanabilirliğine katkı sağlamaktadır. Bu çalışmada, Gümüşhane ve yakın yöresinde yüzeylenen Erken Karbonifer yaşlı Gümüşhane Granitoyidi’nin kazılabilirlik özellikleri incelenmiştir. İlk olarak, dört faklı alan seçilmiş ve bu alanlardaki kaya kütleleri ISRM tanımlama kriterleri esas alınarak ayrışma derecelerine göre gruplandırılmıştır. Bu çalışmalar sonucunda 1, 2 ve 3 numaralı alanlardaki kaya kütlelerinin orta derecede ayrışmış, 4 numaralı alandaki kaya kütlesinin ise ileri derecede ayrışmış kaya sınıfında olduğu tespit edilmiştir. İkinci aşamada, eklemlerin mühendislik özellikleri ve kaya malzemesinin jeomekanik özellikleri belirlenmiştir. Sonraki aşamada ise kaya kütlelerinin RMR89, Q ve GSI değerleri belirlenmiş ve kazılabilirlik açısından sınıflandırılmıştır. Yapılan sınıflamalara göre, orta derecede ayrışmış kaya kütleleri “sökülebilir”, ileri derecede ayrışmış kaya kütlesi ise “kazılabilir” özelliktedir. İnceleme alanlarında yapılan kazı çalışmalarında orta derecede ayrışmış kaya kütlelerinin hidrolik kırıcı kullanılarak söküldüğü, ileri derecede ayrışmış kaya kütlelerinin ise kepçe kullanılarak kazıldığı tespit edilmiştir. Son aşamada ise bulunan sonuçlar ile uygulanan kazı yöntemleri karşılaştırılmıştır. Bu sonuçlara göre, Tsiambaos ve Saroglou (2009) tarafından önerilen kazı yöntemleri, yerinde yapılan kazı çalışmaları ile tamamen örtüşmektedir.
- MakaleYalnız künye2011Applicability of excavatability classification systems in underground excavations: A case study
Kaya, Ayberk; Bulut, Fikri; Alemdaǧ, Selçuk
In this study, applicability of the excavatability classification systems in underground excavations is investigated. For this purpose, the entrance portal of the Konakönü (Arakli{dotless}-Trabzon) tunnel, excavated in volcanic rocks within the scope of Black Sea coastal highway project, is chosen as pilot study area. The entrance portal of tunnel is excavated through the rocks of Eocene-aged Kabaköy formation of basaltic-andesitic tuffs, aglomerate and basalt. In excavation, basaltic and andesitic tuffs were ripped by using hydraulic breaker; aglomerate and basalt were excavated by using explosives. Based on the results obtained from field and laboratory studies, rock masses are classified in terms of excavatability. According to Pettifer and Fookes (1994), basaltic and andesitic tuffs are included in "hard ripping", aglomerate and basalt in "blasting required" categories. With reference to Tsiambaos and Saroglou (2009), basaltic and andesitic tuffs fall in "ripping", agglomerate and basalt in "hammer and blasting" categories. It was found out that the classifications made according to these two methods are completely compatible with in-situ excavation works. Also, it is determined that the parameters give the best results for determining excavation class in underground excavations are GSI (Geological Strength Index), I s (50) (Point load strength index) and I f (Discontinuity spacing index).
- MakaleYayıncıda açık erişim2011Analysis of support requirements for a tunnel portal in weak rock: A case study from Turkey
Kaya, Ayberk; Bulut, Fikri; Alemdaǧ, Selçuk; Sayin, Aytuna
In this paper, engineering geological properties of the entrance portal section of Konakönü Tunnel, located on Black Sea Coastal Highway, Turkey, is studied. Moderately weathered basaltic and andesitic tuffs orderly to be driven by the entrance portal section. Tunnel portal design in weak rock presents some special challenges to the designers, since misjudgements in the design of tunnel can lead to very costly failures. The entrance portal was analyzed by empirical and numerical methods. Both field and laboratory studies were carried out during this study. Field studies involved geological mapping, detailed discontinuity surveying and sampling. Laboratory tests were carried out to determine the physico-mechanical and elastical properties of rock units. For this purpose, tunnel stability analyses were performed at the entrance portal section. The RMR (rock mass rating), Q (rock mass quality), RMi (rock mass index), NATM (new Austrian tunnelling method) and GSI (geological strength index) systems were employed for empirical rock mass quality determination and preliminary tunnel portal support design. The parameters calculated by the empirical methods were used as input parameters for the FEM (finite element method) analysis. The results from the two methods were compared and preliminary support designs were carried out. This comparison suggests that for more reliable support design, empirical and finite element methods should be combined.