Landslide Investigation of a Residential Area in Goynuklu Village, Bursa (Turkey)

Abstract

Landslide is a natural process of the earth's surface, inevitably resulting from gravity with many triggering factors such as rainfalls, earthquakes, slope steepening, removal of vegetation, etc. The most frequent landslide-triggering mechanism is water from intense rainfall or human-based sources. The wide ranges of landslides and the complexity and variability of their interactions with the environment are the key points of a landslide investigation. The rate of the movement is the main factor of high property damages. On 16th of March in 2006, a rapid landslide occurred in Goynuklu village in Bursa, Turkey. The properties were inevitably damaged after the failure. The triggering factors of the failure mechanism and the properties of the landslide were investigated to specify proper remedial measures at the site. The geotechnical investigations including surface and subsurface studies were performed to determine the extent of the landslide and its sliding surface accurately. Within the framework of the geotechnical investigations, the inclinometer measurements were also recorded after drilling boreholes. Besides, a number of trial pits were excavated for evaluating the shallow sliding surfaces. Samples taken from the boreholes and trial pits were tested in the laboratory to obtain the soil class and the distribution of the grain size of the soil layers as well. The field tests including the hydraulic effect on the soil layers were also resolved by means of in situ permeability tests. Based on the data obtained, the characteristics and mechanism of the landslide were analyzed. The landslide occurred on a translational sliding surface in Neogene sediments including non-stratified sandstone-siltstone-claystone layers and a landfill site in a residential area. The shear strength characteristics of the sliding surface were calculated by back-analyses.