ENGINEERING GEOLOGICAL CHARACTERIZATION OF THE ROCK MASSES AND THEIR EVALUATION BY SPATIAL ANALYSES, DETERMINATION OF THE ROCK SLOPE FAILURE SUSCEPTIBILITY ZONES AND HAZARD ASSESSMENT OF MUDURNU (BOLU)

2022-7-20
Arslan Kelam, Arzu
Mudurnu County, which is settled in a valley, is affected by regional rock slope instabilities especially due to precipitation, temperature changes, wind and earthquake activity. While units located on the eastern side of the valley are susceptible to rock falls, units at the western side are susceptible to planar, wedge or toppling failures. The presence of different rock mass properties makes Mudurnu an attractive and distinctive site for the investigation of rock mass failure. The rock slope failures tend to create an important hazard in and around the settlement area and generate regional risk due to exposure of the elements at risk (i.e., human life, houses, buildings and small industrial facilities) in Mudurnu. Moreover, instabilities create a risk to the historically valuable structures by which Mudurnu has been nominated as a candidate for the UNESCO World Heritage List. The purpose of this dissertation is to characterize the rock masses that have the potential to create a hazard in the Mudurnu county center through geomechanical evaluation of the slope instability problems under static and dynamic loading conditions and to identify the hazard zones in the Mudurnu Valley with a focus on the western side of the valley. To that end, the engineering geological and geomechanical properties of the region were assessed through a 3D point cloud generated by an unmanned aerial vehicle (UAV) along with scan-line survey field studies of the physically accessible locations. Then, the data were evaluated statistically to define the discontinuous rock mass characteristics. Accordingly, the western side of the Mudurnu Valley was delineated into 11 geomechanical sectors. The stability analysis demonstrated that the rock mass is prone to planar, wedge, and toppling failures in the area. Moreover, the discontinuity sets can create complex kinematic failures that cause the study area to be a unique case study since it is difficult to separately identify the order or frequency of events originating from the different failure modes forming the complex failure. The hazard potential of the different modes of failures was assessed and hazard zonation maps were generated by considering the conditioning parameters (i.e., lithology, degree of weathering, block size, slope angle, aspect, surface water) along with travel distance and temporal frequency. In addition, the seismic loading was taken into account as a triggering factor. The combined hazard map composed of the planar, wedge and toppling failure potentials concluded that Sectors 6 and 8 were most critical in terms of high hazards. Under dynamic loading conditions, the most critical high-hazard sectors were determined as Sectors 2, 4, 6, 8, and 10.

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Citation Formats
A. Arslan Kelam, “ENGINEERING GEOLOGICAL CHARACTERIZATION OF THE ROCK MASSES AND THEIR EVALUATION BY SPATIAL ANALYSES, DETERMINATION OF THE ROCK SLOPE FAILURE SUSCEPTIBILITY ZONES AND HAZARD ASSESSMENT OF MUDURNU (BOLU),” Ph.D. - Doctoral Program, Middle East Technical University, 2022.