Geological and geotechnical investigation of the central province of Bitlis

The purpose of this study is to evaluate the suitability of the region as a settlement area by conducting a detailed examination of the geological and geotechnical characteristics of the Bitlis Central District. In addition, it aims to determine the engineering bearing capacity and overall construction potential of the soil structure in the region by utilizing scientific data. It is to contribute to the safe construction process by providing important region-specific data for use in urban planning and engineering projects. Both quantitative research methods were used in the field and laboratory environments. In the field studies, a total of 13 main boreholes were drilled, and microtremor measurements were conducted using the Seismic Refraction and MASW (Multi Channel Analysis of Surface Waves) analysis methods in 13 profiles corresponding to each borehole. In connection with these measurements, stratigraphic sections of soil layers were prepared, and representative soil and rock samples were tested in the laboratory. The physical (natural water content, unit weight, particle size distribution, etc.) and mechanical (consolidation, shear strength, bearing capacity, etc.) properties of the soils were determined through laboratory tests. Additionally, the seismic hazard of the study area and the local soil class were determined, and critical parameters for settlement were evaluated. The findings of the study indicate that the Central District of Bitlis is characterized by the presence of various geological units and soils with inadequate engineering properties, and that this situation is particularly evident in alluvial fill areas. In contrast, more suitable areas for construction have been identified in some regions where rock units are exposed at the surface. As a result, the ground in Bitlis Central District is observed to have a heterogeneous structure. Therefore, geotechnical measures such as microzoning, ground improvement, and design appropriate to local ground behavior should be taken into account in construction decisions.