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Pol Johannes C. Kanning Willem van Beek Vera M. Robbins Bryant A. Jonkman Sebastiaan N. 《Acta Geotechnica》2022,17(10):4555-4576
Backward erosion piping (BEP) is a form of internal erosion which can lead to failure of levees and dams. Most research focused on the critical head difference at which piping failure occurs. Two aspects have received less attention, namely (1) the temporal evolution of piping and (2) the local hydraulic conditions in the pipe and at the pipe tip. We present small-scale experiments with local pressure measurements in the pipe during equilibrium and pipe progression for different sands and degrees of hydraulic loading. The experiments confirm a positive relation between progression rate and grain size as well as the degree of hydraulic overloading. Furthermore, the analysis of local hydraulic conditions shows that the rate of BEP progression can be better explained by the bed shear stress and sediment transport in the pipe than by the seepage velocity at the pipe tip. The experiments show how different processes contribute to the piping process and these insights provide a first empirical basis for modeling pipe development using coupled seepage-sediment transport equations.
相似文献2.
The International GLONASS Experiment 1998 (IGEX-98) was the first international tracking campaign of the Russian counterpart
to the Global Positioning System (GPS), GLONASS. Started in October 1998, the campaign was originally scheduled to last for
three months. However, the launch of additional GLONASS satellites and a widespread enthusiasm among the participants led
to an indefinite continuation of the campaign on a “best effort” basis.
At the Delft University of Technology, the data of six IGEX-98 stations have been analyzed in detail with integrity monitoring
software, developed at the Department of Mathematical Geodesy and Positioning of the University. The software aims to detect
outliers and slips in code and phase observations in real time. In addition, the software also allows the validation of the
information contained in the broadcast navigation messages.
The results of the IGEX-98 data analyses will be presented in a three-part series. In the second part, GLONASS outlier and
slips statistics will be discussed, while in the third part the anomaly detection results of the GLONASS and GPS messages
will be shown. In this first part of the series, however, the most basic of all statistics will be considered: a simple day-to-day
count of the number of GLONASS and GPS observations. Although simple, this statistic yields a surprising amount of information
both on the availability of the GLONASS satellites and on the peculiarities of some of the receiver makes participating in
the IGEX-98 campaign. ? 2000 John Wiley & Sons, Inc. 相似文献
3.
Damage to residential buildings due to flooding of New Orleans after hurricane Katrina 总被引：1，自引：1，他引：0
This article analyzes the direct damage to residential buildings caused by the flooding of New Orleans after hurricane Katrina
in the year 2005. A public dataset has been analyzed that contains information on the economic damage levels for approximately
95,000 residential buildings in the flooded area. The relationship between the flood characteristics and economic damage to
residential buildings has been investigated. Results of hydrodynamic flood simulations have been used that give insight in
water depths and flow velocities in the study area. In general, differences between the three polders in the observed distributions
of damage estimates are related to differences in flood conditions. The highest damage percentages and structural damage mainly
occurred in areas where higher flow velocities occurred, especially near the breaches in the Lower 9th Ward neighborhood.
Further statistical analysis indicated that there is not any strong one-to-one relationship between the damage percentage
and the water depth or the depth–velocity product. This suggests that there is considerable uncertainty associated with stage-damage
functions, especially when they are applied to individual structures or smaller clusters of buildings. Based on the data,
a more general approach has been proposed that could be used to distinguish different damage zones based on water depth and
flow velocity for an area that is affected by flooding due to breaching of flood defenses. Further validation of existing
damage models with the dataset and further inclusion of information on building type in the analysis of damage levels is recommended. 相似文献
4.
At the Delft University of Technology (DUT), the data of six stations participating in the first international GLONASS (Global
Navigation Satellite System, the Russian counterpart of GPS) tracking campaign, IGEX-98, were analyzed with integrity monitoring
software. The software was developed at the Department of Mathematical Geodesy and Positioning of DUT. The main function of
this software is to detect slips and outliers in phase and code observations in real time. In addition, the software also
allowe the validation of the information contained in the broadcast navigation messages.
The results of the IGEX-98 data analyses will be presented in a three-part series. In this second part of the series, GLONASS
outlier and slip statistics will be discussed in detail. The first part was concerned with the availability of GLONASS observations,
while in the third one the broadcast navigation message validation results will be considered. ? 2000 John Wiley & Sons, Inc. 相似文献
5.
Methods for the estimation of loss of life due to floods: a literature review and a proposal for a new method 总被引：9，自引：5，他引：4
This article deals with methods for the estimation of loss of life due to flooding. These methods can be used to assess the
flood risks and to identify mitigation strategies. The first part of this article contains a comprehensive review of existing
literature. Methods have been developed for different types of floods in different regions. In general these methods relate
the loss of life in the flooded area to the flood characteristics and the possibilities for evacuation and shelter. An evaluation
showed that many of the existing methods do not take into account all of the most relevant determinants of loss of life and
that they are often to a limited extent based on empirical data of historical flood events. In the second part of the article,
a new method is proposed for the estimation of loss of life caused by the flooding of low-lying areas protected by flood defences.
An estimate of the loss of life due to a flood event can be given based on: (1) information regarding the flood characteristics,
(2) an analysis of the exposed population and evacuation, and (3) an estimate of the mortality amongst the exposed population.
By analysing empirical information from historical floods, new mortality functions have been developed. These relate the mortality
amongst the exposed population to the flood characteristics. Comparison of the outcomes of the proposed method with information
from historical flood events shows that it gives an accurate approximation of the number of observed fatalities during these
events. The method is applied to assess the consequences for a large-scale flooding of the area of South Holland, in the Netherlands.
It is estimated that the analysed coastal flood scenario can lead to approximately 3,200 fatalities in this area.
相似文献
| A. C. W. M. VrouwenvelderEmail: |
6.
Ke Qian Yin Jiangshan Bricker Jeremy D. Savage Nicholas Buonomo Erasmo Ye Qinghua Visser Paul Dong Guangtao Wang Shuai Tian Zhan Sun Laixiang Toumi Ralf Jonkman Sebastiaan N. 《Natural Hazards》2021,109(1):671-703
Natural Hazards - Climate change leads to sea level rise worldwide, as well as increases in the intensity and frequency of tropical cyclones (TCs). Storm surge induced by TC’s, together with... 相似文献
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A proper choice of the observation weight matrix is of importance for both adjusting and testing GPS data. Our understanding
of the noise characteristic of GPS observations, on which the weight matrix should be based, is, however, still underdeveloped.
This makes it difficult to draw up an appropriate weight matrix. The first and foremost purpose of this contribution is therefore
to draw attention to the need to improve upon our rudimentary knowledge of the GPS stochastic model. To this end, results
will be presented of a relatively simple case study in which the possible presence of cross-correlation between observables
is considered. With these results we hope to spur further discussion and research on this important topic. ? 1998 John Wiley
& Sons, Inc. 相似文献
9.
Non Okumura Sebastiaan N. Jonkman Miguel Esteban Bas Hofland Tomoya Shibayama 《Natural Hazards》2017,88(3):1451-1472
This paper presents a methodology for tsunami risk assessment, which was applied to a case study in Kamakura, Japan. This methodology was developed in order to evaluate the effectiveness of a risk-reducing system against such hazards, also aiming to demonstrate that a risk assessment is possible for these episodic events. The tsunami risk assessment follows these general steps: (1) determination of the probability of flooding, (2) calculation of flood scenarios, (3) assessment of the consequences and (4) integration into a risk number or graph. The probability of flooding was approximated based on the data provided by local institutes, and the flood scenarios were modeled in 1D using the Simulating WAves till SHore model. Results showed that a tsunami in Kamakura can result in thousands of casualties. Interventions such as improvements in evacuation systems, which would directly reduce the number of casualties, would have a large influence in risk reduction. Although this method has its limits and constraints, it illustrates the value it can add to existing tsunami risk management in Japan. 相似文献
10.
At the Delft University of Technology (DUT), data of six stations participating in the first international GLONASS tracking
campaign, IGEX-98, were analyzed with integrity monitoring software. The software was developed at the Department of Mathematical
Geodesy and Positioning of DUT. The main function of the software is to detect slips and outliers in phase and code observations
in real time. In addition, the software also allows the validation of the information contained in the broadcast navigation
messages.
The results of the IGEX-98 data analyses are presented in a three part series. In this third and final part of the series,
GLONASS and GPS navigation message validation results will be discussed in detail. The first part was concerned with the availability
of GLONASS observations (Jonkman & de Jong, 2000a), while in the second part, GLONASS slip and outlier statistics were considered
(Jonkman & de Jong, 2000b).
The discussion of the navigation message validation results concentrates on anomalies detected in the data of an IGEX-98 station
in Switzerland. Data collected at this station from September 1998 to December 1999 was analyized. In all, 19 anomalies were
detected by the integrity monitoring software, 8 in GLONASS messages and 11 in GPS messages. The cause of the anomalies was
established by evaluating the original data files, studying official bulletins of the GLONASS and GPS ground segments, and
in some cases tracing the anomaly through the complete IGEX-98 network. ? 2000 John Wiley & Sons, Inc. 相似文献
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