Supervisor(s): China Earthquake Asministration Sponsor(s): China Association for Disaster Prevention; Institute of Engineering Mechanics, CEA CN：23-1324/X
Journal of Natural Disasters, started in 1992, publishes papers on disaster prediction and prevention, disaster risk assessment, disaster mitigation for agriculture, meteorology and city, disaster mitigation policy and management system. It also focuses on social factors of natural disasters, loss prediction of earthquake all over the world, awareness improvement on disaster prevention, the system engineering on disaster prevention and mitigation, and so on.
Director XIE Lili
Assistant Director Ou Jinping, Li Youshan, Shi Peijun, Han Linhai, Xiao Yan, Zhou Xianyan, Cui Jie
Editorial Board Ma Zongjin, Ma Zhiliang, Wang Lanmin, Wang Zifa, Wang Chunyi, Wang Zhenqing, Shan Chunchang, Shi Peijun, Fu Qiang, Lv D
In order to assess the susceptibility of the debris flows along Karakoram Highway at home section,entropy weight method and the theory of extenics were comprehensively applied to establish the debris flow susceptibility evaluation model based on extenics. Combined with the field investigations and the results of the remote sensing image interpretation, 10 evaluation indexes of debris flow susceptibility were determined and then the weight coefficients of the evaluation indexes were also determined by entropy weight method. Then, according to the theory of extenics, the classical domain, joint domain and the cerrelation function were structured and susceptibility level evaluation was carried out for 10 typical debris flow gullies in research area. On the basis of calculation, the debris flow susceptibility of all 10 gullies are in high level. Resuts show that it is reasonable and feasible to assess the susceptibility of debris flows by the model based on the theory of extenics.
Twenty-one cities including, Beijing, Shanghai, Guangzhou, Shenzhen, Tianjin, Chongqing, Wuhan, Chengdu, Nanjing, Hangzhou, Shenyang, Xi'an, Zhengzhou, Harbin, Qingdao, Suzhou, Urumqi, Shijiazhuang, Sanya, Yinchuan, Jinan were selected as the samples and 17 indexes were selected to establish the comprehensive index system of flood control and disaster reduction ability of cities in China. Five principal component factors were extracted by principal component analysis. Through regression analysis, urban flood control and disaster reduction capacity principal component factor score function model was established to comprehensively evaluate and calculate all the cities' score and ranking of urban flood control capacity in China. Therefore, the difference between every cities flood control and disaster reduction capacity principal component factors is evaluated objectively, and the cities with stronger and weaker flood control and disaster reduction capacity can be found out. The paper may provide a reference for determining urban flood control and disaster reduction management measure.
Zoige plateau has been affected by the global climate change, especially the effects of some unreasonable human activities. The ecological restoration and carbon fixation function of the desertified grassland are widely concerned in China and other countries. The plant samples and soil samples were collected from treatment area, and field investigation and experiment analysis of ecosystem restoration process of the treatment area were carried out. Taking spatial structure instead of times series, a lot of methods were used to analyze the change of carbon content, carbon storage and carbon density. The results show that during the 5 years of management and protection: (1) carbon content of the samples changes between 36.67–44.41 g·kg−1, carbon density changes between 8.87–57.62 kg·m−2; carbon storage changes between (10.61–36.56) × 104t·hm−2, and with the increase of treatment years, carbon density and carbon storage show a gradually increasing trend; (2) plant biomass and carbon content have a good linear relationship, the accumulation of plant biomass is beneficial to increase of carbon storage. (3) Physicochemical properties of soil improve and carbon fixation ability recovers with the ecological restoration. It is found in that correlation analysis that soil organic carbon, soil organic matter and texture show a significant positive correlation with water content, and a negative correlation with pH value; (4) by the analysis of meteorological data, the temperature of Zoige area in recent years is higher than its average temperature, the status accelerates the carbon decomposition, and is unfavorable to the balance adjustment of carbon sink-carbon source of grassland. Based on the above results, the research of carbon fixation provides basic data for the treatment of grassland desertification under the background of global climate change, and will also provide a realistic basis for the further improvement of Zoige desertified grassland management and the study of ecological restoration.
Taking Wudu District in the south of Gansu Province as research object, and selecting 25 villages and towns in the district as assessment unit, the regional risk assessment was carried out by using regional hazard and vulnerability as basic assessment indices. The regional hazard was integrated through historical disaster data and field investigation data. At the same time, information method was adopted and 250 m × 250 m basic grid was selected as assessment unit, and then the hazard was obtained. Taking the exposure, the sensitivity and the recovery ability of hazard-affected body into account, with the help of DEA model and C-D function, the vulnerability values of villages and towns in Wudu District were calculated, and then the vulnerability subregion of villages and towns in research region was obtained. Hazard and vulnerability were coupled, and the regional risk coefficient was introduced, and then the risk assessment model was established, based on the risk rank and the risk zoning map of Wudu district which were obtained by using GIS technology. Meanwhile, some suggestions were proposed for disaster prevention and mitigation. The results show that the extremely high risk areas in Wudu district were mainly distributed in the Chengguan Town, Dongjiang Town, Majie Town, Bolin Village, Anhua Town and most parts of Hanwang Town.
Debris flow occurred frequently in mountain areas of China. Qinling-Bashan mountain area is one of debris flow multiple occurring areas. We conducted twice detailed field investigation on Jiaochang Gully of Laoyu Town, Huxian County in north foot of Qinling Mountain and in process of the investigation, inquired and measured the total debris flow substance reserve and their spacial distribution, the size of vertical and cross section of the gully. Based on these data the peak flowrate and total procedure amount of debris flow under different rainfall conditions were calculated according to the rainfall-runoff model for small valleys. Calculation results showed that under strong rainfall with 50-year return period and above, the valley will form considerable debris flow disaster. At last, the deposited scopes of debris flow under different rainfall conditions were analyzed and predicted according to semi-empirical model, which aims to provide scientific reference for debris flow prevention and mitigation in Qinling-Bashan mountain area.
The reinforcement corrosion mechanism and process in concrete was researched considering the chlorion corrosion effect model. Then the degradation model of the diameter and yield strength of the reinforcement was established. In order to study the degeneration law of seismic performance of isolation bridges caused by chlorion corrosion, an offshore isolation bridge exposed to long-term corrosion of chlorion in China was taken as an example, and then finite element model of bridges was established with and without considering the chlorion corrosion effect by use of OpenSees program. Moreover, 15 appropriate seismic waves were selected to conduct IDA analyses. The vulnerability curves of piers and plate-type rubber bearings under different damage states were established according to the ratios of the capacity and demand. Finally, the systematic vulnerability curves of whole bridge were formed based on knowledge of probabilistic theory. Calculations show that plate-type rubber bearing is more vulnerable than pier for isolation bridge. Meanwhile, whole bridge system is more vulnerable than any single component and it is more reasonable to assess the seismic behavior of bridge with systematic vulnerability curve of whole bridge. The seismic vulnerability of the bridge system is increased after considering the reinforcement corrosion, which illustrates that the reinforcement corrosion could not be ignored in the environment of chlorion corrosion.
The unstable rock developed on the soft-hard alternate strata is a multi-medium complex structural rock mass, which shows anisotropic characteristics, and thus the stress state, deformation and failure characteristics of this kind unstable rocks are more complex than single lithological ones. The numerical simulation method based on particle flow discrete element is a good way to study the failure process of such unstable rock. The dynamic response and failure process of particle substance of Wangxia W2 unstable rock on the Wuxia Gorge bank of Yangzi River are simulated using the Particle Flow Code (PFC2D). Results show that the whole W2 rock mass finally sliding down along the lock section of the weak structural surface under the influence of upper gravity load and strength degradation of the soft foundation. The displacement parameters obtained indicate that velocity differences between the top and bottom of W2 rock mass may lead to its dip slip failure. The simulation result is consistent with the actual monitoring data, which shows the feasibility of simulating failure of the unstable rock mass with particle discrete element method.
Under appropriate conditions, strong earthquake would be accompanied with surface rupture, which can cause a huge disaster. So, in the engineering planning and urban construction, especially in major construction projects, we should make the surface rupture assessment. Surface rupture is a result of seismogenic fault extending to the surface. Up to now, human being cannot control the activity of active faults. The disaster of earthquake shows that surface rupture can destroy everything, so the only method is keeping a safety distance from it. Therefore, it is required that we should evaluate the possibility of earthquake surface rupture and provide parameters related to the project construction to make reasonable seismic design, site selection and dodge distance. This article summarizes the concepts, types, and characteristics of the surface rupture, and reviews the related research progress in engineering assessment field about it. The article also introduces the evaluation methods of surface rupture, analyzes the advantages and limitations of different research methods, and sums up the rules of fault avoidance in China and some foreign countries. On the basis of summarizing the results of previous studies and analysis of the current engineering construction needs, five major aspects to be researched in this field are presented. The work discussed in this paper has a certain reference value for the research on engineering evaluation of the surface rupture in strong earthquake.
After the damage of earthquake, some elements of urban traffic network may still be destroyed by secondary disaster and emergency. The cascading failure of network elements may enhance the range and influence of the damage, which leads to catastrophe in disaster rescue. Based on the assessment of post-earthquake remaining road capacity, the consequence of cascading failure after node failure was researched from the point of network ensemble efficiency, and the network connectivity degree and road congestion. Results show obvious difference of cascading failure consequence between different nodes’ failure, and the cascading failure caused by road congestion may reduce traffic efficiency seriously and even lead to traffic interruption. The method presented in the paper may provide a reference for post-earthquake emergency traffic control and protection of important elements of road network.
How to perfect emergency capability efficiently and carry out comprehensive disaster prevention planning is an important issue that earthquake emergency preparedness work faces in China. It is the best way to build a comprehensive emergency response capability abroad that taking the potential disaster scenarios as the goal of emergency preparedness, and then making a disaster prevention plan. According to the ideas of constructing scenarios, this paper introduces a framework of earthquake catastrophe preparedness plan suitable for the emergency response system in China. The framework describes the potential risk as a quantitative model of earthquake scenarios, sorts out the emergency task, and evaluates the emergency response capability by analyzing disaster scenarios. Finally, it makes an emergency defense plan and work suggestion, which has a certain reference sense for the Chinese earthquake emergency preparedness system construction.
