26,558 research outputs found
Slope Instability of the Earthen Levee in Boston, UK: Numerical Simulation and Sensor Data Analysis
The paper presents a slope stability analysis for a heterogeneous earthen
levee in Boston, UK, which is prone to occasional slope failures under tidal
loads. Dynamic behavior of the levee under tidal fluctuations was simulated
using a finite element model of variably saturated linear elastic perfectly
plastic soil. Hydraulic conductivities of the soil strata have been calibrated
according to piezometers readings, in order to obtain correct range of
hydraulic loads in tidal mode. Finite element simulation was complemented with
series of limit equilibrium analyses. Stability analyses have shown that slope
failure occurs with the development of a circular slip surface located in the
soft clay layer. Both models (FEM and LEM) confirm that the least stable
hydraulic condition is the combination of the minimum river levels at low tide
with the maximal saturation of soil layers. FEM results indicate that in winter
time the levee is almost at its limit state, at the margin of safety (strength
reduction factor values are 1.03 and 1.04 for the low-tide and high-tide
phases, respectively); these results agree with real-life observations. The
stability analyses have been implemented as real-time components integrated
into the UrbanFlood early warning system for flood protection
Modeling Earthen Dike Stability: Sensitivity Analysis and Automatic Calibration of Diffusivities Based on Live Sensor Data
The paper describes concept and implementation details of integrating a
finite element module for dike stability analysis Virtual Dike into an early
warning system for flood protection. The module operates in real-time mode and
includes fluid and structural sub-models for simulation of porous flow through
the dike and for dike stability analysis. Real-time measurements obtained from
pore pressure sensors are fed into the simulation module, to be compared with
simulated pore pressure dynamics. Implementation of the module has been
performed for a real-world test case - an earthen levee protecting a sea-port
in Groningen, the Netherlands. Sensitivity analysis and calibration of
diffusivities have been performed for tidal fluctuations. An algorithm for
automatic diffusivities calibration for a heterogeneous dike is proposed and
studied. Analytical solutions describing tidal propagation in one-dimensional
saturated aquifer are employed in the algorithm to generate initial estimates
of diffusivities
Decision Support System for Urbanization of the Northern Part of the Volga-Akhtuba Floodplain (Russia) on the Basis of Interdisciplinary Computer Modeling
There is a computer decision support system (CDSS) for urbanization of the
northern part of the Volga-Akhtuba floodplain. This system includes subsystems
of cognitive and game-theoretic analysis, geoinformation and hydrodynamic
simulations. The paper presents the cognitive graph, two-level and three-level
models of hierarchical games for the cases of uncontrolled and controlled
development of the problem situation. We described the quantitative analysis of
the effects of different strategies for the spatial distribution of the
urbanized territories. For this reason we conducted the territory zoning
according to the level of negative consequences of urbanization for various
agents. In addition, we found an analytical solution for games with the linear
dependence of the average flooded area on the urbanized area. We numerically
computed a game equilibrium for dependences derived from the imitational
geoinformation and hydrodynamic modeling of flooding. As the result, we showed
that the transition to the three-level management system and the implementation
of an optimal urbanization strategy minimize its negative consequences.Comment: 14 pages, 5 figures; Conference: Creativity in Intelligent
Technologies and Data Science. CIT&DS 201
Numerical simulation of the Rio Fucino dam-break flood
In this paper a dam-break flood model based on a contravariant integral form of the shallow water equations is presented. The equations of motion are numerically solved by means of a finite volume-finite difference numerical scheme that involves an exact Riemann solver and is based on a WENO reconstruction procedure. An original scheme for the simulation of the wet front progress on the dry bed is adopted. The proposed model is used to simulate the Rio Fucino dam-break and subsequent flood wave propagation, downstream of the Campotosto reservoir (Italy)
A dam-break flood simulation model in curvilinear coordinates
A dam-break flood model based on a contravariant integral form of the shallow water equations is presented. The numerical integration of the equations of motion is carried out by means of a finite volumefinite difference numerical scheme that involves an exact Riemann solver and which is based on a high-order WENO reconstruction procedure. An original scheme for the simulation of the wet front progress on the dry bed is adopted. The proposed model capacity to correctly simulate the wet front progress velocity is tested by numerically reproducing the dry bed dam-break problem. The model is adopted for the real case study of the Rio Fucino lake-dam collapse and subsequent flood wave propagation, downstream of the Campotosto reservoir (Italy)
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Geographic Information Systems (GIS)-based spatially distributed model for runoff routing
A method is proposed for routing spatially distributed excess precipitation over a watershed to produce runoff at its outlet. The land surface is represented by a (raster) digital elevation model from which the stream network is derived. A routing response function is defined for each digital elevation model cell so that water movement from cell to cell can be convolved to give a response function along a flow path and responses from all cells can be summed to give the outlet hydrograph. An example application of analysis of runoff on Waller Creek in Austin, Texas, is presented.Waller Creek Working Grou
A computer simulation of the Volga River hydrological regime: a problem of water-retaining dam optimal location
We investigate of a special dam optimal location at the Volga river in area
of the Akhtuba left sleeve beginning (7 \, km to the south of the Volga
Hydroelectric Power Station dam). We claim that a new water-retaining dam can
resolve the key problem of the Volga-Akhtuba floodplain related to insufficient
water amount during the spring flooding due to the overregulation of the Lower
Volga. By using a numerical integration of Saint-Vacant equations we study the
water dynamics across the northern part of the Volga-Akhtuba floodplain with
taking into account its actual topography. As the result we found an amount of
water passing to the Akhtuba during spring period for a given water flow
through the Volga Hydroelectric Power Station (so-called hydrograph which
characterises the water flow per unit of time). By varying the location of the
water-retaining dam we obtained various values of as well as various flow spatial structure on the territory during the flood
period. Gradient descent method provide us the dam coordinated with the maximum
value of . Such approach to the dam location choice let us to find the
best solution, that the value increases by a factor of 2. Our analysis
demonstrate a good potential of the numerical simulations in the field of
hydraulic works.Comment: 7 pages, 3 figure
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