Stochastic Models for Three-Dimensional Slope Stability Analysis Considering Groundwater Variations
Date Issued
2007
Date
2007
Author(s)
Madrazo, Adrian Atencio
DOI
en-US
Abstract
Nowadays, with the effects of global warming to the earth’s atmospheric
conditions, the number of various hazardous natural events (i.e. storms, floods,
earthquakes, etc.) has increased significantly every year creating large losses to the
economy, lives, and properties of people. One of these common disasters is caused by
torrential rains or storms, the so-called “landslide”. Numerous methods are available
in estimating the stability of slopes against landslides and in analyzing different
governing factors involved from one-dimensional approach to three-dimensional
cases (Lam and Fredlund, 1993), and from simpler to complex techniques (Duncan,
1996). However, only few models are available that incorporates the effects of rainfall
infiltration in slopes and that uses a three-dimensional analysis using data from
Geographic Information System (GIS). Thus, this study was established and it aims,
generally, to develop simpler models for a 3D slope stability analysis considering the
effect of rainfall infiltration by varying groundwater levels; to verify these models; to
correlate results with other methods; and, to identify unstable slopes in areas of
interests for mitigation purposes. And for this, there were four stochastic models
established. Each was defined from the relationship between the location of failure
surface and of groundwater table, height of increase in the groundwater table, and
from other slope conditions. In the methodology, after gathering the necessary data
and establishing the models, first, it is necessary to identify the probability
distribution function of the random variables selected. Then, a simulation was
conducted by means of a Monte Carlo Simulation Method (MCSM), where iterative
process is involved and which will stop not until values converge (Rubenstein, 1981).
In the results, the mean value and the distribution of the possible factors of safety is
determined, thereby, a probabilistic assessment based on the frequency can be made.
It was found that the number of soil columns used (917 columns of 1mx1m cell size)
is enough to get satisfactory results and was recommended that the number of
iterations be 1000 or higher to meet the convergence criterion.
Subjects
蒙地卡羅模擬
地下水位變化
隨機分析
三維邊坡
Monte Carlo Simulation
rainfall infiltration models
GIS
stochastic
Type
thesis
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