Shear strength in first-time activation and reactivation of Shimajiri-mudstone landslide: An example of Asato landslide, Okinawa, Japan
This paper discussed the shear strengths along the slip surface in the first-time activation and reactivation of Asato landslide, which is a quasi-first activated slide in the area of Shimajiri-mudstone, Okinawa, Japan and its stability analysis utilizing the shear strength characteristics. It is co...
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Veröffentlicht in: | Journal of the Japan Landslide Society 2010/05/25, Vol.47(3), pp.138-146 |
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Sprache: | eng |
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Zusammenfassung: | This paper discussed the shear strengths along the slip surface in the first-time activation and reactivation of Asato landslide, which is a quasi-first activated slide in the area of Shimajiri-mudstone, Okinawa, Japan and its stability analysis utilizing the shear strength characteristics. It is considered that in the reactivation, residual strength is applicable in most of the slip surface area, while the remaining part of it is at the fully softened strength. In the stability analysis during sliding subsequent to the first-time activation, using the residual strength as the average shear strength that acts along the slip surface for the entire slip surface enables estimation of the position of groundwater level. For the first-time activation, the average shear strength acting along the slip surface (c´, φ´) was calculated through the application of the estimated groundwater level. The parameters of c´=26.8kN/m2, φ´=22.9° and the residual factor R=0.49 indicate that both the peak (fractured-mudstone) and the residual (structural weak planes) strength prevail in the slip surface area. The c´- tanφ´ diagrams of stability analysis, which are constructed for the first-time activation and reactivation of the landslide, are beneficial for the control works for landslide. These results can be valuable in the risk evaluation of the quasi-first activated slides. |
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ISSN: | 1348-3986 1882-0034 1882-0034 |
DOI: | 10.3313/jls.47.138 |