Monitored displacements and analyses of slope stability in the Rabenov site
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Insinööritieteiden korkeakoulu |
Master's thesis
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Authors
Date
2015-12-14
Department
Major/Subject
Pohja- ja kalliorakentaminen
Mcode
IA3028
Degree programme
Rakenne- ja rakennustuotantotekniikan koulutusohjelma
Language
fi
Pages
90+5
Series
Abstract
Theoretical part of the study concentrated on landslides and their behaviour, soil mechanical behaviour in stability of slopes and different analysis types for analysing stability of slopes. Monitoring methods for borehole deformations were discussed in brief. Fiber optical monitoring and applications exploited in monitoring ground and ground structure is discussed. For fiber optical monitoring, most interest is in Fiber Bragg Grating sensor cables. Fiber optical monitoring was also compared to inclinometer monitoring for deformations. The practical part concentrated on a former mining area in Usti nad Labem in Northern Czech Republic, which is under renovation process after the mining activity discontinued. The total size on area is 40 hectares. The area has shown signs of instability with shallow slides as well as visible deformations and results from displacement monitoring. The aim in this study is to gain knowledge on the stability of the upper part of this area, where a water supply line is located. Area is under monitoring with fiber optical and inclinometer monitoring. The case was analysed with three different types of methods: limit analyses (LEM), limit analyses with probability approach and finite-element method (FEM) analyses with elasto-plastic and limit analyses. Analyses were computed with Geo 5, Geostudio’s SLOPE/W and FEM program Optum G2. Several parameters sets were analysed to study the effect of variation in parameters used for analysis. Analyses resulted in factor of safety against failure for different cases. Results from limit analysis studies and finite-element method studies show, that the area has acceptable factor of safety against failure with Eurocode with fully saturated soil. When there is an excessive amount of pore-pressure in the ground, factor of safety decreases. FEM analyses prove, that most dis-placements are relatively small, under 20 mm, and occur in upper part of the area near the monitored point. Higher level of ground water table is related to higher displacements. In FEM analysis, only very small displacements occur with a low ground water table. The resulting displacements of monitoring and observations are compared to results of analyses (LEM and FEM).Description
Supervisor
Korkiala-Tanttu, LeenaThesis advisor
Korkiala-Tanttu, LeenaKeywords
limit equilibrium method, geotechnical monitoring, optical monitoring, finite-element method