Candan GÖKÇEOĞLU, Murat ERCANOĞLU, Harun SÖNMEZ

Kama türü yenilmelerin olasılıklı risk haritasının hazırlanmasına bir örnek: Altındağ (Ankara)

Eklemli kaya kütleleri içerisinde yapılan şev duraylılığı araştırmalarının en önemli aşamalarından birisini stereografik projeksiyon tekniklerini kullanarak gerçekleştirilen kinematik analizler oluşturur. Klasik yöntemler kullanılarak kaya şevlerinin olası yenilmelerinin incelenmesinde, eklem yönelimlerinin en yoğun olduğu konumun yanı sıra şev geometrisi ve zayıflık düzleminin sürtünme açısı parametre olarak kullanılır. Bu durumda merkezde yoğunlaşmayan ancak şevin duraysizliğini kontrol edebilecek diğer konumlar gözardı edilir. Bu çalışmada Ankara ve ,civarında yüzeylenen eklemli andezit kütlesi içerisinde gelişebilecek olası kama türü yenilmelerin analizi hem klasik kinematik analiz hem de olasılıklı kinematik analiz yöntemleriyle araştırılmış ve elde edilen sonuçlar kullanılarak risk haritaları üretilmiş ve bir karşılaştırma yapılmıştır.

An example for preparation of probabilistic risk map of wedge type failures: Altındağ (Ankara)

The evaluation of potential rock slope failures using stereographic projection techniques known as kinematic analysis is one of the most important parts of a slope stability investigation to be carried out in in jointed rock media. In conventional stereoprojection techniques for the assessment of possible rock slope failures, the peak orientations of joints together with the slope geometry and the friction angle of the weakness planes are used. Other possible joint orientations which may be encountered in the rock media are ignored. In the present study, possible wedge failures which can develop in jointed andesites cropped out Ankara and its vicinity were investi-gated using both conventional and probabilistic kinematic analysis methods, and risk maps were produced using the results obtained from kinematic analysis and a comparison was made between the results. According to the results obtained from this study, probabilistic risk map are more realistic than the map using conventional kinematic analysis, because, all the actual wedge type slope failures developed in the study area are located on the risk zones of the probabilistic risk map. When three peak orientations of the discontinuities are used for the preparation of the risk map, 20% of the study shows wedge type failure risk. However, this value goes up to 73% when the probabilistic kinematic analysis is applied. In conclusion, each possible discontinuity orientation must be taken into consideration in a kinematic analysis research program. This phenomenon is important for the selection and planning of settlement regions particularly, because, a failure can cause important hazards and loss of life. Besides, the procedure described in the present study is very simple.

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