Hazard Degree Research Articles

Hazard assessment and zoning of collapse along highways in China based on backward cloud algorithm

Evaluation indices were proposed and rated based on statistical analysis of collapse by an improved backward cloud algorithm considering internal and trigger factors. The evaluation index weight was calculated by a G1 method. A hazard evaluation of a highway collapse in China was established on the basis of a spatial analysis function of ArcGIS 10.2 and a factor superposition method. A hazard zoning of highway collapse in China was also performed based on the hazard degree. Results show that a comprehensive hazard index of highway collapse hazard in China based on the evaluation index above ranges from 1.0 to 9.0; and the distribution law of the collapse along a highway coincides with the actual distribution of highway collapse hazard. The most dangerous zones are the mountainous area of Southeast Taiwan, the mountainous area of Southeast Fujian–Zhejiang, south of Hainan, Sichuan–Yunnan mountainous area, Tianshan Mountains and Kunlun Mountains. The results can provide a reference for highway collapse prevention and mitigation work.Abbreviations: AHP: Analytic Hierarchy Process; GIS: Geographic Information System

Application of Reliability-Centered Maintenance in Metro Door System

Metro door system (MDS) is one of the most important and fault-prone parts of metro train. Reliability-centered maintenance (RCM) is a systematic engineering process for determining the preventive maintenance requirements of equipment and optimizing the maintenance system. This paper is motivated to apply RCM to the maintenance of metro door system. Firstly, the subsystems and components of MDS are introduced. Then a fuzzy FMECA method is proposed to define the hazard degree of 10 failure modes from 5 components with high failure rate to conduct reliability analysis. Finally, reliability-centered maintenance strategy is made after maintenance mode decision and calculation of maintenance interval cycle, which provides theoretical basis to the maintenance of the metro train.

Estimating the rockburst hazard of hard rocks based on laboratory test results

The results of laboratory tests of samples are used to estimate rock proneness to dynamic fractures, in particular, by brittleness index. A common drawback of the approaches in use is that they do not expressly consider the main condition of dynamic rock fracture – rock mass ability to accumulate energy when loaded. The article discusses the results of studies of the nature of elastic energy accumulation during loading and deformation of samples of various rocks under uniaxial compression in order to assess the degree of their explosion. The approach is original as it studies the deformation curve of rocks at the pre-peak stage that may be obtained with any standard equipment without the use of special-purpose test (“rigid”) devices. Results of the studies conducted on standard test devices have allowed us to identify two different deformation patterns for the rock type tested with further establishment of criteria of rock classification by the degree of proneness to dynamic fractures. This approach is of practical value as it specifies the geomechanics zoning method of the rock mass and improves the assessment of rockburst hazard degree of specific areas at deposits being developed.

Мультиплікативна оцінка впливу організаційних факторів ризику на безпеку польотів при управлінні повітряним рухом

Мета: систематизувати фактори ризику організаційного характеру в системі управління повітряним рухом та оцінити їх комплексний вплив на безпеку польотів. Методи дослідження: ступінь небезпеки організаційних факторів при управлінні повітряним рухом визначено методом експертних оцінок, шкалу прийнятності (допустимості) факторів ризику організаційного характеру побудовано на основі теорії нечітких множин із застосуванням лінгвістичних змінних. Результат: виявлено, що технічні системи та засоби управління повітряним рухом здійснюють найсильніший вплив на безпеку польотів при управлінні повітряним рухом, а політика управління та структура компанії – найслабший. Отримано мультиплікативну функцію оцінювання стану безпеки польотів при управлінні повітряним рухом, яка дозволяє перевірити відповідність значень організаційних факторів ризику встановленому максимально допустимому рівню небезпеки. Обговорення: запропонована методика оцінювання впливу організаційних факторів ризику на безпеку польотів при управління повітряним рухом дозволить розробити паспорти безпеки, які можуть застосовуватись Державіаслужбою України при проведенні сертифікаційних перевірок провайдерів аеронавігаційних послуг для порівняння нормативних та фактичних показників їх діяльності.

Morphometric, statistical, and hazard analyses using ASTER data and GIS technique of WADI El-Mathula watershed, Qena, Egypt

An attempt to carry out morphometric, statistical, and hazard analyses using ASTER data and GIS technique of Wadi El-Mathula watershed, Central Eastern Desert, Egypt. Morphometric analysis with application of GIS technique is essential to delineate drainage networks; basin geometry, drainage texture, and relief characteristics, through detect forty morphometric parameters of the study watershed and its sub-basins. Extract new drainage network map with DEM, sub-basin boundaries, stream orders, drainage networks, slope, drainage density, flow direction maps with more details is very necessary to analyze different morphometric and hydrologic applications for the study basin. Statistical analysis of morphometric parameters was done through cluster analysis, regression equations, and correlation coefficient matrix. Clusters analyses detect three independents variables which are stream number, basin area, and stream length have a very low linkage distance of 0.001 (at very high similarity of 99.95%) in a cluster with the basin width. Main channel length and basin perimeter (at very high similarity of 99.83%) are in a cluster with basin length. Using the regression equations and graphical correlation matrix indicates the mathematical relationships and helps to predict the behavior between any two variables. Hazard analysis and hazard degree assessment for each sub-basin were performed. The hazardous factors were detected and concluded that most of sub-basins are classified as moderately to highly hazardous. Finally, we recommended that the flood possibilities should be taken in consideration during future development of these areas.

Developing an overall assessment map for flood hazard on large area watershed using multi-method approach: case study of Wadi Qena watershed, Egypt

Many parts of Upper Egypt as Sinai and Red Sea areas were hit by severe flash floods since 1976. Wadi Qena is considered one of the most watersheds that suffers from floods in Red Sea area. It was recorded by the General Authority for Roads, Bridges & Land Transport (GARBLT) that the flash flood destructive effect always occurs on El-Geesh–Hurghada Road which is located in the southern part of Wadi Qena watershed. The current study investigates the assessment of endangered areas in Wadi Qena watershed based on a suggested concept of multi-method approach which is a combination of morphometric ranking method and El-Shamy approach. The morphometric analysis is applied using set of parameters which are classified into three categories: basin geometry, drainage network and texture, and relief parameters. For basin geometry, the considered parameters are the watershed area (A), elongation ratio (Re), circularity ratio (Rc), form factor (Ff), and compactness coefficient (Cc). For drainage network and texture parameters, stream frequency (F), texture ratio (Rt), length of overland flow (Lo), and drainage density (D) parameters are considered. For relief parameters, the parameters are mean basin slope (Sm), relief ratio (Rr), and ruggedness number (Rn). A filtration process for the above twelve parameters is considered for reducing the number of parameters by omitting the parameters which have inverse effect on the flood severity of the study area. It is concluded that six parameters have a direct effect on sub-basin hazardous including A, D, Lo, Sm, Rr, and Rn. Sensitivity analysis is concerned for ranking the selected parameters by their significant parameters in assessing the most hazard sub-basins. An overall assessment map is constructed showing the hazard degrees of the sub-basins. The constructed map concludes that the sub-basins are divided into moderate and high hazard ones. Moreover, the results show that the high hazard degree sub-basins are concentrated in the middle and east of the watershed with a percentage of 18.5% of the total area. The developed overall assessment map can be used for assessment and mentoring processes of flood mitigation and planning.

Influences of ethane on the flammable limits and explosive oxygen concentration of methane with nitrogen dilution

To comprehensively investigate the impact of ethane (C2H6) on methane (CH4) explosions, a standard test device for the flammable limits of combustible gases was used to examine the influence of C2H6 on the CH4 explosion parameters with nitrogen dilution. The flammable limits for CH4 in air and under a nitrogen atmosphere in the presence of C2H6 were obtained. Additionally, the critical index behaviors were analyzed, and the CH4 explosive triangles at different operating modes were drawn. Using the explosive diagrams, the effects of C2H6 on the location and area of the CH4 explosive triangle were analyzed. Both the lower and upper flammable limits were reduced by the addition of C2H6. Simultaneously, the explosive hazard degree (F value) increased. Furthermore, the inerting nitrogen concentration at the converging point for the CH4 explosion linearly increased with the increase in C2H6, whereas the explosive oxygen concentration decreased. The CH4 explosive triangle expanded and shifted to the left bottom corner in the presence of C2H6. The area of the explosible zone increased, while that of the no explosion zone decreased. Meanwhile, the ratio of the inert gas and combustible gas required to depress the explosion significantly increased, and more inert gas was required to maintain CH4 in a completely inert state.

Selection of optimal escape routes in a flood-prone area based on 2D hydrodynamic modelling

Abstract Optimizing escape routes during an extreme flood event is an effective way to mitigate casualties. In this study, a model for selecting optimal escape routes in a flood-prone area has been proposed, which includes a module for predicting the two-dimensional (2D) hydrodynamics and modules for assessing the hazard degree for evacuees, calculation of evacuation times and determination of different escape routes. In the module for determining escape routes, two evacuation schemes were used: scheme A to find optimal escape routes based on established road networks and scheme B to design a new optimal evacuation route. Extreme overbank floods occurred in the Lower Yellow River (LYR) in July 1958 (‘58.7’) and August 1982 (‘82.8’) and the proposed model was applied to select the optimal escape routes on a typical floodplain area of the LYR for these two floods. Model predictions indicated that: (i) the optimal escape routes for these two floods were the same for all three starting locations, and the optimized routes provided 3 h more time for evacuees to escape; and (ii) the time of evacuation would need to be earlier for the ‘58.7’ flood because of its larger amount of water volume and higher peak discharge.

Environment & Safety Risk Analysis of Storage Tank Accidents Based on Vulnerability, Process Management and Emergency Management

This paper aims to assess the risks of storage tank accidents and identify proper countermeasures. For these purposes, the causes and scope of tank accidents were discussed, and the scope of risk assessment was expanded from accident possibility and consequence severity to the hazard degree and vulnerability of the hazard-affected bodies. Then, the risk of storage tank accidents was evaluated from three aspects: accident possibility, hazard degree and vulnerability. Then, several risk control measures were put forward with the aim to control the hazard sources, block the propagation path and decrease vulnerability. After that, the proposed measures were validated through a case study on an oil tank farm of a coastal refinery in China. Specifically, a full-surface fire was simulated on one of the oil tanks in the tank farm, the effects of the fire on the adjacent tanks and pipe rack were observed, and several countermeasures were proposed to minimize the hazards. The research findings shed new light on the understanding and prevention of storage tank accidents.

Typhoon-triggered Debris Flow Hazard Prediction in Southeast Mountain Area in Zhejiang Province

This paper presents a debris flow hazard prediction procedure for different prediction stages. At preliminary prediction stage, Melton ratio (R) is applied to predict the debris flow basing on its linear connection with debris flow occurrence frequency during Typhoon Rananim. At detailed prediction stage, a factor-combined model is brought in to predict the hazard degree. The prediction procedure is applied to 14 typical debris flows in southeast mountain area in Zhejiang Province, the results conform to the characteristics of typhoon-triggered debris flows in study area.

Combination of Rainfall Thresholds and Susceptibility Maps for Dynamic Landslide Hazard Assessment at Regional Scale

We propose a methodology to couple rainfall thresholds and susceptibility maps for dynamic landslide hazard assessment at regional scale. Both inputs are combined in a purposely-built hazard matrix to get a spatially and temporally variable definition of landslide hazard: while statistical rainfall thresholds are used to accomplish a temporal forecasting with very coarse spatial resolution, landslide susceptibility maps provide static spatial information about the probability of landslide occurrence at fine spatial resolution. The test site is the Northern part of Tuscany (Italy), where a recent landslide susceptibility map and a set of recently updated rainfall thresholds are available. These products were modified and updated to meet the requirements of the proposed procedure: the susceptibility map was reclassified and the threshold set was expanded defining additional thresholds. The hazard matrix combines three susceptibility classes (S1, low susceptibility; S2 medium susceptibility; S3 high susceptibility) and three rainfall rate classes (R1, R2, R3), defining five hazard classes, from H0 (null hazard) to H4 (high hazard). A key passage of the procedure is the appropriate calibration and validation of the matrix, letting the hazard classes have a precise meaning in terms of expected consequences and hazard management. The employ of the proposed procedure in a regional warning system brings two main advantages: (i) it is possible to better hypothesize when and where landslide are expected and with which hazard degree, thus fostering a more effective hazard and risk management (e.g. setting priorities of intervention); (ii) the spatial resolution of the regional scale warning system is markedly refined because from time to time the areas where landslides are expected represent only a fraction of the alert zone.

Analysis and hygienic assessment of 9-year dynamics of morbidity with temporary disability in shipbuilders

The authors studied dynamics of transitory disablement morbidity in shipbuilders with small length of service, using annual increase of health risk parameters and comparing these parameters with those in the workers with longer length of service. Over 10 years, the observation covered demographic characteristics, health state (transitory disablement morbidity, medical examination data) and work conditions of workers, specialists and authorities of major shipbuilding enterprise. Overall amount of the observations of transitory disablement morbidity equalled to 15995 human-hours. Annual increase of health risk is the most adequate and necessary criteria in risk-oriented approach to evaluation and forecasting of occupational hazards’ influence on workers’ health. Hazard degree of work conditions in workers with 1–4 years of service in higher than that in the same occupation workers with longer length of service. Maximal values of transitory disablement morbidity are seen on 4th year of service. Optimal range of service for transitory disablement morbidity analysis is 1–2 years interval for hazard degree 4, 1–3 years for hazard degree 3, 1–4 years for hazard degree 2, and 1–10 years for hazard degree 1.

Acute contact toxicity of insecticidal baits on honeybees Apis mellifera: a laboratory study

The honeybee Apis mellifera L. (Hymenoptera: Apidae) is an important pollinator, an object of human economic activity and a bioindicator of environmental pollution. Insecticides used in Agriculture for treatment of plants, bee colonies, and farm animals may be dangerous for bees. This paper reports the results of a comparative assessment of the acute contact toxicity of four toxic bait formulations designed for insect pest control on livestock farms to the honeybees. Toxic baits consisted acetamiprid, ivermectin, chlorfenapyr, and fipronil, with residues of which on the filter paper adult bees contacted on plastic containers. It was found that the bait formulation with ivermectin manifested toxicity slower than the other ones. We used probit analysis to calculate median lethal doses (LD 50 ) of each active substance showed that their toxicity to bees decreased in the following order: fipronil – ivermectin – chlorfenapyr – acetamiprid. Considering the mass content of active substances in formulations, median lethal doses of toxic baits were 202.6 μg/bee (bait with fipronil), 229.3 μg/bee (bait with ivermectin), 1188.3 μg/bee (bait with chlorfenapyr), and 6552 μg/bee (bait with acetamiprid). Thus, bait formulations themselves may be considered practically non-toxic to bees, since their LD 50 exceeded the threshold value of 100 μg/bee. Assessment of hazard degree for bees by the hazard index showed that the insecticide bait containing acetamiprid were less dangerous than the other three bait formulations under laboratory conditions. The future semi-field and field studies are needed to evaluate the possible exposure and the hazard degree of insecticidal baits for bees under conditions close to practice use of these formulations.

Flash Flood Risk Estimation of Wadi Qena Watershed, Egypt Using GIS Based Morphometric Analysis

Flash flooding is one of the periodic geohazards in the eastern desert of Egypt where many parts of Upper Egypt, Sinai, and Red Sea areas were hit by severe flash floods, for example in 1976, 1982, 1996 and January 2010. The hazard degree for each sub-basin was determined using the approach developed by El-Shamy for assessing susceptibility of sub-basins to flash flooding risk. To identify at-risk sub-basins, two different methods were applied. The first method is based on the relationship between the drainage density and bifurcation ratio, and the second one uses the relationship between drainage frequency and bifurcation ratio. The three morphometric parameters (the bifurcation ratio, drainage density, and stream frequency) were extracted and calculated for each sub-basin of the watershed. Based on the final hazard degree resulting from the two methods, a detailed hazard degree map was extracted for all sub-basins. The results illustrate that there are no sub-basins with low risk of flooding. The sub-basins with the highest hazard degree are concentrated in the middle of the watershed although they have smaller areas compared with the surrounding sub-basins. The sub-basins located at the boundary of the watershed have an intermediate risk of flooding and moderate potential for groundwater recharge. This constructed map can be used as a basic data for assessment of flood mitigation and planning.

Preparation of a flood-risk environmental index: case study of eight townships in Changhua County, Taiwan

To evaluate flood-prone areas, correlation analysis of flooding factors for the quantitative evaluation of hazard degree was determined to assist in further disaster prevention management. This study used flood-prone areas in 35 villages over eight townships (Changhua, Huatan, Yuanlin, Xiushui, Puyan, Hemei, Dacun, and Erlin) in Changhua County as research samples. Linear combination was used to evaluate flood-prone environmental indices, and an expert questionnaire was designed by using the analytic hierarchy process and the Delphi method to determine the weights of factors. These factors were then used to calculate the eigenvector of a pairwise comparison matrix to obtain the weights for the risk assessment criteria. Through collection of disaster cases, with particular focus on specifically protected areas where flooding has occurred or is likely to occur, public adaptation and response capabilities were evaluated by using an interview questionnaire that contains the items of perceived disaster risk, resource acquisition capability, adaptation capability, and environment understanding and disaster prevention education. Overlays in a geographic information system were used to analyze the flood-risk degree in villages and to construct a distribution map that contains flood-prone environment indices. The results can assist local governments in understanding the risk degree of various administrative areas to aid them in developing effective mitigation plans.

Analysis on Heavy Metal Distribution in Overlying Deposit and Pollution Characteristics in Rivers around Dahongshan Fe&Cu Mine in Yunnan Province, China

Dahongshan Fe&Cu mine in Yunnan Province was endowed with the title of “National Green Mine Pilots” by Chinese Ministry of Land and Resources in April 2013. In order to verify the implementation effects of the green mine and better drive the construction of the green mine by other mine enterprises in Yunnan, the project team investigated overlying deposit in rivers around the Dahongshan mine in the wet season (August) of 2016, investigated mine enterprises, and applied the Potential Ecological Risk Index to evaluate potential ecological hazards of heavy metal pollution in overlying deposit. The results showed that all sampling points were less than 105, indicating the lower ecological hazard degree.

Numerical simulation of a high-speed landslide in Chenjiaba, Beichuan, China

High-speed landslide is a catastrophic geological disaster in the mountainous area of southwest China. To predict the movement process of landslide reactivation in Chenjiaba town, Beichuan county, Sichuan province, China, we simulated the movement process of two landslide failures in Chenjiaba via rapid mass movement simulation and unmanned aerial vehicle images (UAV), and obtained the movement characteristic parameters of the landslides. According to a back analysis, the most remarkable fitting rheological parameters were friction coefficient (μ = 0. 18) and turbulence (ξ = 400 m · s-2). The parameter of landslide pressure was applied as the zoning index of landslide hazard to obtain the influence zone and hazard zoning map of the Chenjiaba landslide. Results show that the Duba River was blocked quickly with a landslide accumulation at the maximum height of 44.14 m when the Chenjiaba deposits lost stability. The hazard zoning map indicated that the landslide hazard degree is positively correlated with the slope. This landslide assessment is a quantitative hazard assessment method based on a landslide movement process and is suitable for high-speed landslide. Such method can provide a scientific basis for urban construction and planning in the landslide hazard area to avoid hazards effectively.

Principles for the assessment and mapping of integrated geological hazard in Bulgaria

The territory of Bulgaria is at risk of a number of unfavorable and destructive geological processes and phenomena constituting the geological hazard. The generally high hazard degree necessitates analyzing, evaluation and mapping of the geological hazard and risk processes. Evaluation and mapping of geological risk is the final stage of a long-lasting gathering of information for each destructive geological process. The purpose of the present study is to analyze the principles and order in assessing and mapping the overall geological hazard. Typical hazardous geological processes for the territory of our country are taken into account (active faults, abrasion/sea erosion, erosion, landslides, rockfalls, collapse, swelling, liquefaction of dispersed soils, etc.). A methodological approach is presented to combine all hazardous geological processes into an integrated hazard map. The study presents the results obtained during the implementation of the project “Elaboration of analysis, evaluation and mapping of geological risk” realized in 2016 by a large research team and supported by the Ministry of Regional Development and Public Works in Bulgaria.

Landslide zoning analysis in Zhouqu under different rainfall warning levels

Landslide zoning is crucial for disaster prevention and reduction in areas of rainfall-triggered landslides. A shallow-layer landslide assessment model was established for Zhouqu area, simulation of the slope stability of extensive area was applied to predict the potential landslide fairly, and evaluation of the migration and conversion laws were performed to determine quantitatively the effect of rainfall on landslide under different rainfall warning levels. The results show that all 169 recorded landslide scars were classified as lower stability-to-defended by SINMAP model, and the susceptible landslide distribution in low-lying area is consistent with that in areas with relatively high topographic precipitation. With the rainfall intensity increases from 10 to 56 mm/h, the landslide and rainfall were found to exhibit a growing power function relation; the potentially unstable region is always the highest, highlighting a critical problem. Moreover, as the basically stable region and potentially unstable region gradually transition into the unstable region and extremely unstable region, respectively, the landslide potential increases gradually, and the hazard level becomes increasingly aggravated; consequently, the potential threat is more serious. When the hourly rainfall exceeds 20 mm, the slope stability is gradually weakened in the stable region, which is gradually migrating into the unstable region, thus triggering landslides, debris slides and flows. When the hourly rainfall exceeds 32 mm, the hazard degree changes qualitatively, caused by the quantitative change, and the geological hazard degree increases significantly. The study can provide a scientific basis for landslide zoning, monitoring, and early warning in the Zhouqu area as well as other alpine gully area.

Flash flood hazard zonation based on basin morphometry using remote sensing and GIS techniques: A case study of Wadi Qena basin, Eastern Desert, Egypt

Remote Sensing techniques with GIS were used to evaluate flash flood hazard in Wadi Qena. Wadi Qena represents a large, wide, dry and long valley slopes down from the south of the Galala height to the town of Qena. Its southern stretches considered as very promising land for the agriculture expansion. The surface area of Wadi Qena is about 15,588km2. Flash flood hazard in Wadi Qena is evaluating by the integration of some quantitative geo-morphometric parameters and Tropical Rainfall Monitoring Mission (TRMM) satellite data of the last flashflood in 28th January 2013. Streams were automatically extracted from ASTER DEM data. Wadi Qena classified into 151 sub-basins. The various morphometric parameters of Wadi Qena sub-basins have been computed. flash flood hazard map of the most dangerous sub-basins was prepared by combining all the spatial layers of morphometric parameters for the sub-basins included in it by GIS analysis. the majority of the sub-basins range from low to medium hazard degree Except one sub-basin located at the eastern part of the wadi is classified as high hazard degree. This technique may help in evaluating the hydrographic basin and offers a base map delineating both recharge and flooding area. Flash flood has double-edged effects one is a destructive and life terminator, the second is a beneficent, if it can be controlled and directed for the development the community. This technique helps in diminishing the flood hazards and increases recharging the shallow aquifers.