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Rockfall impact on protection galleries

Abstract:

Rockfalls are one of the most prevailing natural hazards in the mountainous regions in Switzerland. Concrete protection galleries are used to protect the local infrastructure and lifelines against these potential rock impacts. Cushion materials are laid on these galleries to absorb the rockfall impact energy, which is one of the main input parameters in the design of the protection gallery. An attempt has been made to reduce the impact energies by placing a better damping material on the gallery. The high rock impact energy ranges are difficult to model at the laboratory scale. Field tests are generally avoided due to the high costs involved and also due to the singularity of the potential tests. The prototype energy levels can be achieved at the laboratory scale with the help of a geotechnical centrifuge. An instrumented model of the protection gallery is rotated under high g levels, thereby increasing the unit weight of the material. With the help of appropriate scaling laws, the prototype energy levels can be achieved. This paper focuses on the determination of the impact force of a rockfall of a specific energy and the forces induced in the gallery. The maximum acceleration values of the rock and deflection of the galleries are compared for different energy ranges and cushion materials. The test results are later compared with numerical modelling using the finite element program LS-DYNA.

Authors:

Chikatamarla, Ravikiran and Laue, Jan and Springman, Sarah M.

Index Terms:

Protection Structures; centrifuge modelling; impact; Soil; SoilGroup

Further Information:

Date published: 2004