THESIS
2013
xx leaves, 207 pages : illustrations (some color) ; 30 cm
Abstract
Realistic prediction of earthquake-induced sliding displacement over a large area is
critical for a variety of applications, such as regional-scale risk and loss assessment, landslide-related
damage to lifelines, road systems and portfolios of infrastructures. To date, most
landslide hazard analyses are only applicable to individual site. The existing methods cannot
be applied directly to spatially distributed systems since the key information about the spatial
correlation of ground motion intensity measures (such as the peak ground acceleration) cannot
be properly considered in the analysis. Compared to a single site analysis, a regional-scale
landslide hazard analysis is highly intricate in nature since the spatial distribution of ground
motion intensities over the region and...[
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Realistic prediction of earthquake-induced sliding displacement over a large area is
critical for a variety of applications, such as regional-scale risk and loss assessment, landslide-related
damage to lifelines, road systems and portfolios of infrastructures. To date, most
landslide hazard analyses are only applicable to individual site. The existing methods cannot
be applied directly to spatially distributed systems since the key information about the spatial
correlation of ground motion intensity measures (such as the peak ground acceleration) cannot
be properly considered in the analysis. Compared to a single site analysis, a regional-scale
landslide hazard analysis is highly intricate in nature since the spatial distribution of ground
motion intensities over the region and interdependency of spatially-distributed components
must be considered. The proposed research develops a new analytical and computational
framework to rigorously evaluate the earthquake exposure of manmade and natural slopes in a
regional scale. The thesis solved the following key technical challenges:
(a) Quantifying the joint occurrence and spatial distribution of various ground motion
intensity measures at multiple sites, which is essential to generate regional correlated intensity
measures. Observed time history records obtained from a large number of recent earthquake
data from California, Japan, Mexico and Taiwan are used to study the relationships between
intra-event residuals of intensity measures. Influences of the regional geological condition on
the spatial correlation are also investigated for a regional specific application. The importance
of spatial correlation is also highlighted using some demonstrated examples.
(b) Developing a computationally efficient method to stochastically simulate all sources
of uncertainties in a fully probabilistic analysis. For a fully probabilistic landslide hazard
analysis, three levels of variabilities must be rigorously accounted for: uncertainties existed in
earthquake scenario level, ground motion intensity level and the predictive displacement level. Conventional Monte Carlo simulation will result in prohibitive computational cost. Using
some state-of-the-art data reduction techniques, the proposed method can accurately simulate
the spatially-distributed intensity measures over the whole region at a computational cost
reduced by three orders of magnitude compared to the conventional Monte Carlo simulation.
(c) Proposing a new one-step Newmark displacement model using seismological
variables (like moment magnitude, rupture distance) rather than intensity measures. The new
developed model can yield hazard-consistent predicted displacement compared to other
displacement models for various earthquake scenarios. In addition, the computational time for
this model is dramatically reduced due to its one-stage process.
(d) Developing some improved models to predict the earthquake-induced permanent
displacements of various slopes using multiple intensity measures. The Newmark
displacement method is not applicable to deeper landslide. For these flexible slopes, a
nonlinear coupled stick-slip deformable sliding model is appropriate to estimate the
permanent sliding displacement. Some selected intensity measures are identified to represent
different characteristics of earthquakes and can significantly improve the seismic slope
displacement predictions under a wide range of slope conditions.
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