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Natural Hazards - This work examines the period affected by extreme rainfall that triggers debris flow and the modification of the critical rainfall threshold for debris flows after extreme events... 相似文献
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A critical relation for mobilization (failure) of an inclined, uniform soil layer is developed, based on the requirement for
balancing the driving stress and the resistance stress acting on the soil layer. Taking into consideration of the uncertainties
of parameters of the considered soil layer, the equation of the failure probability (Eq. 18) and the equation of the critical slope at various probabilities of failure (Eq. 22) for the soil layer by applying the first-order second-moment method (FOSM) were developed. The failure probabilities at
various mean relative water depths subject to the upper and lower values of the coefficients of variations of parameters and
two inclined angles of the soil layers are also estimated by using the Monte Carlo simulation method (MCSM) as well as by
using FOSM for comparisons. The results obtained by FOSM are in good agreement with that obtained by MCSM, but the former
is more efficient. Given the mean values and the coefficients of variation of related parameters of the soil layer, one can
easily estimate the failure probability and the critical failure slope of the soil layer by applying the equations or graphs
developed in the present study. 相似文献
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Geomorphic characteristics of hillslope and channelized debris flows: A case study in the Shitou area of central Taiwan 总被引:1,自引:0,他引:1
The data on the hillslope and channelized debris flows in the Shitou area of central Taiwan occurred during Typhoons Toraji and Nali in 2001 were applied in this paper. The geomorphic parameters, including the flow length, gully gradient, drainage area and form factor of the debris flows were determined by spatial analysis using a Geographic Information System (GIS) based on the data derived from field investigation, aerial photographs, and topographical maps. According to such determined geomorphic parameters, the threshold conditions and empirical equations, such as the relationship between the gully gradient and drainage area and that between gully length and drainage area and topographic parameter, are presented and used to distinguish the geomorphic characteristics between the channelized and hillslope debris flows. 相似文献
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Variability of impact of earthquake on debris-flow triggering conditions: case study of Chen-Yu-Lan watershed,Taiwan 总被引:1,自引:1,他引:0
Jinn-Chyi Chen 《Environmental Earth Sciences》2011,64(7):1787-1794
This study investigates the variations in the critical conditions for debris-flow occurrence before and after the Chi-Chi
earthquake in the Chen-Yu-Lan watershed, Taiwan. Topographical and rainfall parameters such as the gully gradient, drainage
area, rainfall intensity, cumulative rainfall, and rainfall duration in the Chen-Yu-Lan watershed were used to analyze the
conditions of debris-flow occurrence over the past 25 years. A recovery equation was proposed on the basis of rainfall parameters
and used to determine the variations in the critical line of rainfall that trigger debris flow after the earthquake and to
evaluate the recovery period required for the rainfall threshold of debris-flow occurrence after the earthquake to return
to that before the earthquake in the watershed. The critical line for the runoff parameter versus gully gradient in the watershed
was also presented. 相似文献
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Probabilistic analysis of landslide potential of an inclined uniform soil layer of infinite length: application 总被引:1,自引:0,他引:1
An extended probabilistic model that is a modification of the Chen et al. (2007,) model for evaluating the failure probability
of an inclined soil layer with an infinite length was developed in the present paper, and then applied to evaluate the occurrence
probability of landslide-related debris flow in Tungmen gully located in the eastern Taiwan, which occurred a devastating
debris flow in 1990. The statistical properties of hydrogeological parameters were collected and summarized, and then used
to evaluate the landslide-related debris-flow probabilities at various relative water depths for Tungmen gully by using the
probabilistic model. Under the assumption that the soil is saturated, the soil’s cohesion is negligible and the specific gravity
of the solid particles of soils is a constant, a simplified probabilistic critical slope equation for the stability of an
infinite slope of soils was also developed, and used to estimate the occurrence probability of debris flow. The result shows
that probabilistic landslide analysis for an infinite slope could provide a suitable approximation for the risk analysis of
debris flow mobilization at a given gully. 相似文献
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