A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Possible failure mechanisms of landslides in loess deposits
Loess is a geological formation consisting of silt, clay and a small amount of sand transported and laid down by the wind. Due to the mountainous landscapes and neotectonic features, the landslides occurred in loess deposits are a major hazard in Central Asia. Ongoing field observations and investigations in Kyrgyzstan show an increasing landslide activity triggered by rainfalls and earthquakes in these regions. They indicate that the development of tension cracks in the upper part of the slope has a crucial effect on slope failure, especially in loess deposits. However, previous research studies do not clearly explain how these tension cracks impact loess slope stability. On one hand, many studies agree that existing cracks in the slope facilitate the infiltration of surface water, which may then contribute to failure. On the other hand, few have analysed the influence of the seismic response of ground cracks on slope stability. This thesis is focused on the latter effect, considering loess slope stability under dry conditions. The first part gives an overview and introduces the state of the art of current research. The second part of this research introduces the physical and mechanical properties of sampled soil that is obtained from the two landslides that are located in the Upper Mailuu-Suu Basin. Strength parameters are defined by performing of direct shear tests, triaxial tests and by using of ring shear tests. The third part presents the study of the seismic response of the slope by numerical simulations, using a 2-D finite difference code named FLAC. Tension cracks are modelled as nets of fissures and parameters as a length, direction and position within the slope crest are varied. As a case study, the Upper Koi-Tash landslide is studied.
Possible failure mechanisms of landslides in loess deposits
Loess is a geological formation consisting of silt, clay and a small amount of sand transported and laid down by the wind. Due to the mountainous landscapes and neotectonic features, the landslides occurred in loess deposits are a major hazard in Central Asia. Ongoing field observations and investigations in Kyrgyzstan show an increasing landslide activity triggered by rainfalls and earthquakes in these regions. They indicate that the development of tension cracks in the upper part of the slope has a crucial effect on slope failure, especially in loess deposits. However, previous research studies do not clearly explain how these tension cracks impact loess slope stability. On one hand, many studies agree that existing cracks in the slope facilitate the infiltration of surface water, which may then contribute to failure. On the other hand, few have analysed the influence of the seismic response of ground cracks on slope stability. This thesis is focused on the latter effect, considering loess slope stability under dry conditions. The first part gives an overview and introduces the state of the art of current research. The second part of this research introduces the physical and mechanical properties of sampled soil that is obtained from the two landslides that are located in the Upper Mailuu-Suu Basin. Strength parameters are defined by performing of direct shear tests, triaxial tests and by using of ring shear tests. The third part presents the study of the seismic response of the slope by numerical simulations, using a 2-D finite difference code named FLAC. Tension cracks are modelled as nets of fissures and parameters as a length, direction and position within the slope crest are varied. As a case study, the Upper Koi-Tash landslide is studied.
Possible failure mechanisms of landslides in loess deposits
Mögliche Bruchmechanismen von Böschungen in Löss Ablagerungen
Mamyrova, Raushan (author) / Universitätsbibliothek Braunschweig (host institution) / Stahlmann, Joachim (tutor)
2012
Miscellaneous
Electronic Resource
English
DDC:
624