Çağlayan barajı göl alanındaki heyelanların çok zamanlı stabilitesinin incelenmesi

This dissertation includes a multi-temporal slope stability assessment of landslides in the reservoir area of a planned Çağlayan Dam on the Kayacık River, Akhisar, Manisa. The slopes are comprised of Neogene aged clastic and carbonate sedimentary rock intercalations. It was aimed to reveal the multi-temporal evolution and volume of landsides, to determine the effect of triggering factors, and to estimate the future slope conditions. In this study, in-situ geotechnical and geophysical surveys, static and dynamic laboratory testing, photogrammetric analyses with multi-temporal aerial photography, stereographic projection technique and numerical modeling methods were combined. A combination of several photogrammetric techniques to enhance the accuracy of the landslide volume estimation were recommended. It was determined that the reactivations between 1953 and 2017 are the repeated development of the same type of movement in smaller scales and closely related to the triggering factors. A new approach to back analyses to estimate the post-failure strength of joint and rock mass properties using the finite element method (FEM) on geotechnical slope models was developed. Deterministic analyses of future slope stability scenarios were also performed with FEM. It was determined that shallow topsoil and debris cover (0.74 m to 8.55 m) can collapse at the worst conditions (drawdown, seismic activity, and heavy rainfall simultaneously). It can be avoided by trimming the upper weak layers. Although seepage along discontinuities is not expected, the presence of karstic gaps and the intensely faulted rock mass will provide leakage from the dam reservoir.