HR: 0800h
AN: H51C-0379    [Abstracts]
TI: Process and Mechanism of Notch Growth-Induced Rock Fall on Vertical Coastal Slopes in Boso Peninsula: Evidence From Field and Numerical Studies
AU: * Diop, S
EM: souleymane-diop@aist.go.jp
AF: University of Tsukuba, Doctoral Program in Earth Evolution Sciences, Tsukuba, 305-8572 Japan
AU: OGAWA, Y
EM: yogawa@arsia.geo.tsukuba.ac.jp
AF: University of Tsukuba, Doctoral Program in Earth Evolution Sciences, Tsukuba, 305-8572 Japan
AU: ZHANG, M
EM: m.zhang@aist.go.jp
AF: AIST, National Institute of Advanced Industrial Science and Technology, Tsukuba, 305-8567 Japan
AB: To examine the influence of notch evolution on the stability of very steep or nearly vertical slopes, geomechanical surveys were conducted along Ubara-Katsuura coastal area in Boso Peninsula, Japan. These surveys involved the characterization of slope outcrops made of Neogene marine alternation of sandstone and mudstone, the evaluation of joint sets distribution, as well as sampling of rock specimens for laboratory testing and analyses. The work reported here refers to the genesis and evolution of notch and, consequently, the close relationship that these phenomena have with the processes responsible for the local rockfall occurence. A series of parametric studies was carried out to evaluate stress and displacement distribution near the free surface of a vertical slope as a function of notch height, width and depth. The simulation procedure has been described and the model has been found to work consistently. Results presented here, based on Finite Element Method (FEM) model using SAGE CRISP 3-D Bundle , indicate a reasonable agreement with the limit-equilibrium stability analysis model. The results also showed that assessing notch geometry can provide an effective tool in predicting the rock-mass stability, determining the mechanism by which blocks fail from a vertical slope, and the consequent repetitive slope failures through time. Insights from this case shed more light on the complex interactions existing between the notch evolution and slope failure through the analysis of stress-displacement conditions within the slope. Keywords: Finite element method; jointed rock mass; notch; stability; vertical slope.
DE: 1824 Geomorphology: general (1625)
DE: 1859 Rocks: physical properties
DE: 5114 Permeability and porosity
DE: 8010 Fractures and faults
DE: 8020 Mechanics, theory, and modeling
SC: Hydrology [H]
MN: Fall Meeting 2005