Toppling and sliding in volcanic bimrocks around Bayrakli (Izmir, Turkey) Toppling and sliding in volcanic bimrocks around Bayrakli (Izmir, Turkey)

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Vol17 No.2: 429-500

Title】Toppling and sliding in volcanic bimrocks around Bayrakli (Izmir, Turkey)

Author】Recep KILIÇ; Koray ULAMIŞ*

Addresses】Ankara University, Department of Geological Engineering, Gölbaşı 06830, Ankara, Turkey

Corresponding author】Koray ULAMIŞ

Citation】Kiliç R, Ulamiş K (2020) Toppling and Sliding in Volcanic Bimrocks Around Bayrakli (Izmir, Turkey). Journal of Mountain Science 17(2).


Abstract】Discontinuities have significant role on the behavior of rock masses with respect to several types of instabilities. Excavability, deformability, bearing capacity and slope stability of the rock masses should be investigated considering the discontinuity characteristics with particular emphasis on the geomechanical properties. Kinematic analyses mostly provide an insight to the instabilities, however the dimensions of the blocks bounded by discontinuities, their geomechanical properties and the geometry of the slope should also to be taken into account. The study area is in the abandoned stone quarry in Bayraklı district of İzmir residential area. Due to the excavations and discontinuity orientations, instabilities have occured. Miocene aged andesites and altered agglomerates of Yamanlar Volcanics form the bimrock mass. The study area is located within a sheared zone, bounded by strike slip fault zone. Intact andesite blocks were encountered in altered agglomerate matrix, forming a volcanic bimrock. Wedge and planar sliding and block toppling were observed within the area. Detailed discontinuity surveying was conducted, combined with core drillings. Several typical locations were detected where prismatic blocks of andesites are bound to experience block toppling. Such locations are nearby the top of the steep slopes. Agglomerates are subjected to mainly sliding and the blocks have been formed not by gravity but by peculiarities of the volcanic sedimentation and, probably by subsequent tectonics. In order to determine the mechanism of the sliding and toppling in more details, the relation of the blocks and the slope geometry were investigated. Bimrock type volcanic rock masses sometimes do not tend to accommodate the general rules of toppling and sliding due to their anisotropic settings.

Keywords】Volcanic bimrock; Toppling; Sliding; Discontinuity; Bayrakli