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Gewählte Doctoral Thesis:

Rick Veenhof (2021): A Study on Fibre and Grass Slope Stabilization.
Doctoral Thesis - Institut für Geotechnik (IGT), BOKU-Universität für Bodenkultur, pp 150. UB BOKU obvsg FullText

Data Source: ZID Abstracts
Landslides in form of slope failure cause huge loss in life and property worldwide. However, well documented database is often rather scanty since many data are not available, e.g. morphology, meteorological data, hydro-mechanical properties of soil, reinforcement by plant roots etc. Therefore, physical modelling offers an interesting and cost effective alternative. In this thesis, the hydro-mechanical effects of reinforcements on the stability of model slopes are considered. The model slopes consist of silty sand in loose conditions. At first, reinforced sand specimens with various void ratios and fibre- and root densities were tested with the direct shear apparatus and the triaxial shear test. Moreover some tensile strength tests were also performed. Contrary to many previous stu­dies, the focus in this study was on low confining pressures to mimic the stress state near ground surface. Centrifuge model tests were conducted on model slopes with different fibre- and root densities at different locations along the slope. It is observed that failure is delayed by the presence of reinforcement. The location and density of the reinforcement play a key role in the slope behaviour as indicated by the location of the shear band and the displacement. The centrifuge tests in combination with the limit equilibrium analysis indicate that root stretching, root slip­page or the progressive breaking of roots (fibre bundle model) are the major mechanisms that need to be taken into account in order to estimate the added soil strength from vegetation. Our model tests show that the well-known Wu's model gives rise to an overestimation of the soil strength provided by roots. Therefore, some corrections are introduced. The correction factors suggested for Wu's model are 0.48 to 0.85 for Hordeum Vulgare species and 0.52 to 0.63 for Poa Pratensis species. The outcomes of the physical tests can be used as benchmark for the numerical modelling of reinforced slopes.

Betreuer: Wu Wei
1. Berater: Florineth Florin

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