Dik Yamaçlardaki Kaya Düşme Tehlikesinin Değerlendirilmesi: Ermenek (Karaman, Turkiye)

Ermenek, topoğrafik özellikleri nedeniyle Karaman (Turkiye) ili sınırları içerisindeki en ilginç yerleşim alanıdır. Yerleşim yeri, 1250 m’den 1850 m’ye yükselen eklemli kireçtaşlarından oluşan oldukça dik, sarp kayalıkların kuzey tarafında yer almaktadır. Bunun yanı sıra, yaklaşık 90° eğime sahip olan bu şevler, kaya birimlerin litolojik ve mühendislik özellikleri ile iklim etkisi nedeniyle kaya düşmesi kaynak alanlarıdır. Şimdiye kadar, Ermenek’te kaya düşmesi nedeni ile yaklaşık 500 konut ağır hasar görmüş ve can kaybı ile sonuçlanan kaya düşmeleri meydana gelmiştir. Çalışma alanındaki kaya düşmelerine neden olan etmenler; süreksizlikler, litolojik değişiklikler, iklim ve donma-çözülme süreci olarak tanımlanabilir. Bu çalışmada; yürütülen yoğun ve detaylı süreksizlik analizleri ile asılı, ayrılmış ve düşmüş blokların yerleri ve boyutları saptanmış, ayrıca jeolojik, morfolojik ve topoğrafik özellikleri belirlenmiştir. Buna ek olarak, kaya düşmesi tehlikesi, 10 profilde iki boyutlu kaya düşmesi analizleri ile değerlendirilmiştir. Kaya düşmesi analizi sırasında, her bir profil için çeşitli boyutlarda blokların kaçma mesafesi, sıçrama yüksekliği, kinetik enerji ve hızları RocFall v4.0 paket programı kullanılarak belirlenmiştir. Kaya düşmesi analizinden elde edilen sonuçlar, muhtemel kaya düşme tehlike bölgelesi alanlarını belirlemek için kullanılmış ve kaya düşmesi kaynak alanları yorumlanmıştır. Yapılan kaya düşmesi analizleri, saha çalışmaları ve laboratuar deney sonuçlarına göre, kaya düşmesi tehdidi altında olan alanlar için koruyucu ve önleyici yöntemler önerilebilir. Ancak, literatürdeki en yaygın yöntemler olan; hendekler, istinat duvarları, tel örgüler, gerdirme ağlar, kaya saplamaları vb., çalışma alanının topoğrafik, atmosferik ve litolojik özellikleri nedeniyle yetersiz kalmaktadır. Bu nedenle, bölgede yaşayan sakinlerin daha güvenli olabilmeleri amacıyla, öncelikle tehlike bölgeleri tahliye edilmeli ve sonrasında, güvenlik önlemleri alınarak, erişilebilen yerlerde asılı bloklar temizlenmelidir.

Assessment of Rockfall Hazard on Steep Slopes: Ermenek (Karaman, Turkey)

Ermenek is a extraordinary settlement area due to its topographical features in Karaman (Turkey). The city is located in the northernside of the steep cliffs, which are formed of jointed limestone that abruptly increases from 1250 m to 1850 m. Moreover,these cliffs, having a slope dip of nearly 90°, are the main rockfall source areas due to their lithological characteristics, climaticeffects and the engineering properties of rock units. Up to now, depending on the rockfall event, nearly 500 residences havebeen severely damaged, and the loss of life has occurred in Ermenek. The rockfall phenomenon is initiated by discontinuities,lithological changes, weathering and the freeze-thaw process in the study area. In this study, extensive fieldwork including thedetermination of locations and dimensions of hanging, detached and fallen blocks; a detailed discontinuity survey; and the descriptionof geological, morphological and topographical characteristics was performed. Additionally, rockfall hazard has beenevaluated by two-dimensional rockfall analysis involving 10 profiles. While these profiles were determined, the locations wherethe most of the fallen blocks are observed are selected in the field study. During the rockfall analysis, run-out distance, bounceheight, kinetic energy and the velocities of various sizes of blocks for each profile were determined through the use of RocFallv4.0 software. The results obtained from the rockfall analysis were used to map the areas of possible rockfall hazard zones, androckfall source areas were interpreted.According to the rockfall analysis, field study and laboratory testing, protective and preventive recommendations can be suggestedfor the areas threatened by rockfall. However, the most widely known remedial measures in literature, such as trenches,retaining walls (barriers), wire mesh, cable/stretching nets and rock bolting, etc., are not sufficient in the study area due to itstopographical, atmospheric and lithological features. For these reasons, hanging blocks in the reachable locations can be removed,the total evacuation of the danger zone may applied, and then taking safety measures in this area to make it safer forthe residents.

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