Afşin-elbistan Havzası, Çöllolar Açık İşletmesi Heyelanlarının Hareket Mekanizması Yönünden İncelenmesi

Abstract

İstanbul Teknik Üniversitesi Fen Bilimleri Enstitüsü Jeoloji Mühendisliği Anabilim Dalı'nda yüksek lisans tezi olarak hazırlanan bu tezde 6-10 Şubat 2011 tarihlerinde meydana gelen heyelanlara sebep olan mekanizma araştırılmaya çalışılmıştır. Çalışma alanı 1/25.000 ölçekli topoğrafik haritada Kahramanmaraş L 37 b3; L 38 a4 paftaları içinde yer almaktadır. Bu çalışma büro ve arazi çalışmaları olarak 2 aşamada gerçekleştirilmiştir. İlk aşamada bölge hakkında ayrıntılı bir çalışma yapmak amacıyla literatür araştırması yapılmış, ilgili tezler ve raporlar incelenmiş; saha hakkında bilgiler derlenmiştir. Jeoloji haritası olarak arazide Staesche (1972)'nin haritası kullanılmış ve araziden elde edilen veriler ile harita revize edilmiştir. Sahada ki jeolojik birimler temelden üste doğru incelenmiş; Temel kayaçlar, Mesozoyik karbonatlı kayaçlar, Neojen gölsel çökeller ve Kuvaterner birimler olarak ayrılarak sıralanmışlardır. Bu birimlerin içerisinde ise özellikle Kuvaterner birimler üzerinde durulmuştur ve bu birim kendi içerisinde sahada ki gözlemlere dayanarak akarsu çökelleri, alüvyal yelpaze, taşkın düzlükleri, taraçalar ve kalişler olarak ayrılmıştır. Heyelanlara birçok kaynakta en büyük sebep olarak su gösterilmektedir. Gerek yağışlar gerek akarsular, dereler, kaynaklar ve yeraltı suları ele alınmıştır. Devlet Meteoroloji İşleri'nden alınan 18 yıllık yağmur verileri incelenmiş, ortalamaları ve eklenik sapma değerleri hesaplanmış ve grafiğe dökülerek yorumlanmıştır. Kurak ve yağışlı dönemler belirlenmiştir ve içinde bulunduğumuz dönemin yağışlı dönem olduğu sonucuna varılmıştır. Ortamdaki jeolojik birimler suyu iletebilme özelliklerine göre geçirimsiz, yarı geçirimli ve geçirimli birimler olarak 3'e ayrılmış, yaşanan heyelan hadiselerine olası etkileri tartışılmıştır. Çalışmanın asıl amacı olan Çöllolar Açık İşletmesi'nin heyelanlar üzerine yorum yapmadan önce heyelan üzerine yapılan çalışmalar araştırılmış, birçok bilim insanının yaptığı sınıflamalar tez içerisinde sıralanmıştır. Çalışma alanında ki heyelanlar arazi çalışmalarında incelenmiş, fotoğrafları alınmış, litolojik özellikleri belirlenmeye çalışılmış ve hareketin şekli ortaya konulmaya çalışılmıştır. Arazi çalışmalarından elde edilen bulgular ve gözlemlere dayalı olarak yapılan değerlendirmeler, batı şevlerinde meydana gelen heyelanın yenilme mekanizmasının progresif kayma modeline uygun olduğunu göstermektedir. Doğu şevlerinde meydana gelen heyelanın yenilme mekanizmasının ise oldukça karmaşık bir yapıda olduğu o kaymanında progresif kayma şeklinde gözlendiği söylenebilir. Bu kayma, birleşik iki kayma yüzeyi üzerinde makaslama yenilmesine bağlı olarak meydana gelmiş olmalıdır. Kaymanın 1. yüzeyini (tabandaki yüzey) killerle geçişli kömür seviyesi, 2. yüzeyini (arka yüzey) ise süreksizlikler oluşturmaktadır. Büyük olasılıkla tabandaki kayma yüzeyinin üzerinde bulunan yeraltı suyu ve tabandaki 1. kayma yüzeyini oluşturan malzemelerin zayıf dayanımına sahip olmaları şevlerdeki heyelanı meydana getiren ana faktörler olmalıdır.

Mechanism causing landslides hit between 6 and 10 February 2011 were studied to clarify in thesis prepared as Master of Science (M.Sc.) thesis in the Department of Geological Engineering, Institute of Science and Technology, Istanbul Technical University. Study area is located in Kahramanmaraş L 37 b3; L 38 a4 map sections of 1/25.000 scale topographic maps. This study was carried out as office and field work in 2 phases. In the first phase, the literature survey was carried out so as to make a detailed study about the area, related theses and reports were examined, information about the field was compiled. In the second phase to made the field work by going to land, landslides examined, lithology, slope angle, the region's rainfall, underground and surface water of the predisposing factors causing landslides are examined. Photographed the landslide area. For the obtain strike and dip of the layers of landslide area outside and inside was measured. In the field compass for geologists, geologists hummer, and GPS are used. Staesche (1972) map was used as geological map and data obtained from the field was revised. The geological map which was revised drawn on the computer again and the value of direction and inclination of layers was measured marked on the geological map. However, discontinuities was observed in the geological units marked on the map. In addition to, terraces which can carry water marked to on the map. During the field study, the drilling data from borehole logs made from MTA and EÜAŞ used for the ensuring thickness of coal and other geological units. These borehole logs are made by MTA for determining the the coal mine evaluation. In this study, three of borehole logs are used which are selected close to the mine. In the first, a literature review was carried out about the basin. Then the study area is a coal basin, research is concentrated on coal basins. As a result of this research there are two ways in which class of coal basin that have been found. The first of these types of is according to the environment where the sediments basins. The second is the According to the development of the shape of the basin and coal basins. According to this informations Afşin-Elbistan coal basin is limnic and asymetric foredeep basin. In this study, the geological units have been approached with informations taken from previous studies. To naming of geological units are avoided from previous studies. Geological units in the field were examined from bottom to top; by separating basement rocks, Mesozoic carbonate rocks, Neogene lacustrine sediments and Quaternary as units were sorted. Among these units, it was particularly focused on the Quaternary units and this unit in itself was separated into the fluvial deposits, alluvial fans, flood plains, terraces and caliches based on observations in the field. Stratigraphic column section of geolocic units are drawn. On this stratigraphic column section is painted with the same color of geological map which used in this study. In addition to divergent between in geological units are shown in this stratigraphic column section. Afşin Elbistan basin is a region that has been exposed quite a lot of tectonic effects. For his reason, this tectonic effects shaped to basin are interpreted. For this purpose, structural features of geological units researched in both litearture survey and in the field. As a result of this researches, it has Watercourse) been found that the Hurman faultline (analogous with Hurman river) narrows the pit field from east and Kışlaköy Faults narrows the pit field from West. Location of these faultlines are marked on the geological transverse section this locations obtained from Staesche (1972). In addition, these geological transverse section are drawn on the computer. Water is shown as the biggest reason of landslides in many sources. As the presence of water in the field, precipitation, streams, creek, springs and groundwater sources are considered. 18 years of rain data received from Turkish State Meteorological Service; mean and cumulative deviations were calculated, graphed and interpreted. Dry and wet periods were determined and it was concluded that the period we are in is the rainy period. Geological units were separated into 3 as impermeable, semi-permeable and permeable; potential impacts on landslides occurred were discussed. Before Çöllolar, the main aim of the study, made comments, the studies conducted on landslides were investigated and classifications made by many scientists were listed in the thesis. Landslides in the study area were examined in the field studies, their photographs were taken and lithological features were tried to be determined and shape of the movement was tried to be revealed. During these researches, especially focused on the progressive landslides and this type of landslides whether suitable to Çöllolar open pit or not was tried to observe in the field. Additionally, in this study, prevention of landslides are takes place too, precuation from landslides was expressed. Assessments based on the findings and observations obtained from area studies have showed that landslides occurred in the western slope are suitable for failure mechanism of the progressive model shift. Landslides occured in the western slope was drawn on the computer with the drawing program and shown the estimated sliding surface. The failure mechanisms of the landslides occurred in eastern slope is quite a complex structure and firstly it can be said that it is in the shape of annular slip based on progressive slide and superficial findings and observations. Landslides occured in the eastern slope was drawn on the computer with the drawing program and shown the estimated sliding surface like other western slope. Progressive slip should be occurred on the combined two slide surfaces depending on shear failure. Permeable coal level with clay constitutes 1st surface of slide (bottom surface) and discontinuities constitute 2nd surface (back surface). Most likely, the groundwater on the slide surface on the base, the material forming 1st slide surface having weak strength should be the main factors of landslides occurrence on the slope. Landslides occured in the Çöllolar open pit's slopes' lithological features shown below of same name of this title in this study and below of this title was indicated water carrying characteristics, thickness, spread features of these slopes' lithological units. The result of experiments conducted with landslide material which taken from slopes are given in this study. These results are internal friction angle, cohesion, unit weight and these results given in this study. Landslides type of the western and eastern slopes was found suitable for progressive landslide from result of literature survey and field work. Many research indicated that water is the main reason of landslides. Water is reason of landslides of the Çöllolar open cast mine ,result of interaction with water entering the mine and geological units in the mine is concluded. Water of the Çöllolar open cast mine must be carried with Hurman river and terraces structures. In study area, in terms of water transport terraces located in whole basin very important because these terraces structures overlooks like groove duty.