Characterization and Assessment of Large Landslide Movement Along the Bursa-Inegöl-Bozüyük Highway in Turkey

Abstract

This study discusses the geotechnical characterization, modeling and stabilization of a large scale landslide that occurred in highly weathered rock during highway construction. The study area is located along the Bursa-İnegöl-Bozüyük highway in Turkey. The mass movement occurred 110 m behind the road cut with 400–600 mm wide tension cracks. Some remediation techniques were applied on site while mass movements were continuing and the size of the tension cracks that were located at the crown reached a width in the order of a meter. A detailed geomechanical and geotechnical site investigation including engineering geological boring, standard penetration test, pressuremeter tests, inclinometer measurements along with laboratory test data was performed at the project site. Detailed engineering geological mapping was performed to document the observed slope movements. In the light of the compiled data, critical profiles were determined and back analysis was performed through comparing the displacement obtained from the inclinometer results and the finite element model. Regarding the back analyses, the site was modeled using coupled slope stability analyses along the most representative profile by considering the landslide mechanism, the parameters evaluated from the geotechnical investigations, the size of the landslide and the location of the slip circle. Since the project site is located in the vicinity of the Eskişehir Fault Zone, pseudo-static and dynamic stability of the site were also evaluated. As a result, the most suitable slope remediation technique was determined to be a combination of surface and subsurface drainage, application of rock buttress at the toe of the landslide and unloading of the landslide material.