Model and Method of Debris Flow Risk Zoning Based on Momentum Analysis

A model of debris flow risk zoning is carried out with momentum analysis of debris flow. This model zones the debris flow inundation fan with density and velocity calculated by numerical simulation. The risk classification standard is determined according to the ultimate bearing capacities of different structures under impacting. And the ultimate bearing capacities are tested by impact failure experiment of destruction. Two structures typical in Chinese mountain towns, reinforced concrete frame construction and brickwork with concrete, are chosen in the experiment. The model makes debris flow risk zoning quantitative and the results comparable widely. The results differ much from that of other methods especially in the identification of medium and low risk zones.

Risk assessments of debris flow based on improved analytic hierarchy process and efficacy coefficient method

In order to evaluate the danger of debris flow properly, eight factors were selected as the risk assess- ment indexes of the debris flow, namely the vertical slope, valley relative difference, hillside slope, area of ba- sin, loose solid material reserves, the path length of sediment supply probability, silting and scouring derrieking and vegetation coverage. The improved Analytic Hierarchy Process （ AHP ） method was used to obtain the weights of the factors; and the efficacy coefficient method was adopted to evaluate the risks of six typical debris flow gullies. According to the research, the improved AHP method not only avoids the subjectivity in the indi- vidual factor valuation by comparing two factors of each layer, but also makes the subsequent consistency check unnecessary.

GIS-Based Risk Assessment of Debris Flow Disasters in the Upper Reach of Yangtze River

This paper discussed theory and methodologies of debris-flow risk assessment and established an implementation process according to indicators of debris-flow hazard degree, vulnerability, risk degree, etc. Among these methodologies, historical and potential hazard degree was comprehensively considered into hazard assessment and hazard index was presented to indicate the debris-flow hazard degree. Regarding debris-flow vulnerability assessment, its statistical data and calculating procedure were based on the hazard-degree regionalization instead of administrative divisions, which improved the assessing scientificity and precision. These quantitative methodologies integrated with Geography Information System （GIS） were applied to the risk assessment of debris flows in the upper reach of Yangtze River. Its results were in substantial agreement on investigation data and the actual distribution of debris flows, which showed that these principles and methodologies were reasonable and feasible and can provide basis or reference for debris-flow risk assessment and disaster management.

Method and its application of the momentum model for debris flow risk zoning

In order to ascertain the distribution of flow depth and velocity of debris flow, the combination of nu-merical modeling and the GIS technology has been used to simulate the movement process of debris flow out of the out-let. The main model of momentum classification of risk zon-ing of debris flow is Z=Khv. Based on the distribution of the velocity and depth of debris flow, the distribution of mo-mentum can be ascertained. Thereby the classification of risk zoning of debris flow can be worked out. A case study of Chacaito Valley in Caracas, Venezuela, is presented to illus-trate the application of the method.

A catastrophic debris flow in the Wenchuan Earthquake area,July 2013：characteristics,formation,and risk reduction

In the Wenchuan Earthquake area,many co-seismic landslides formed blocking-dams in debris flow channels. This blocking and bursting of landslide dams amplifies the debris flow scale and results in severe catastrophes. The catastrophic debris flow that occurred in Qipan gully(Wenchuan,Southwest China) on July 11,2013 was caused by intense rainfall and upstream cascading bursting of landslide dams. To gain an understanding of the processes of dam bursting and subsequent debris flow scale amplification effect,we attempted to estimate the bursting debris flow peak discharges along the main gully and analyzed the scale amplification process. The results showed that the antecedent and triggering rainfalls for 11 July debris flow event were 88.0 mm and 21.6 mm,respectively. The event highlights the fact that lower rainfall intensity can trigger debris flows after the earthquake. Calculations of the debris flow peak discharge showed that the peak discharges after the dams-bursting were 1.17–1.69 times greater than the upstream peak discharge. The peak discharge at the gully outlet reached 2553 m^3/s which was amplified by 4.76 times in comparison with the initial peak discharge in the upstream. To mitigate debris flow disasters,a new drainage channel with a trapezoidal V-shaped cross section was proposed. The characteristic lengths(h1 and h2) under optimal hydraulic conditions were calculated as 4.50 m and 0.90 m,respectively.

DIFASTERS AND REGIONAL RISKS OF DEBRIS FLOW IN ZHAOTONG PREFECTURE，YUNNAN PROVINCE，CHINA

Zhaotong Prefecture has the area of 22,434km2, where there are more than 330 debris flow ravines, with the average spatial density of 14.7 spots per 1,000km2. According to the method of evaluation on the regional risk of debris flow,this study has come to the following conclusions: Qiaojia County-risk grade V,Yongshan, Yanjin, Ludian, Daguan, Weixin and Zhenxiong counties-risk grade Ⅲ;Yiliang, Suijiang-Shuifu and Zhaotong City-risk grade Ⅱ.Compared with the field investigation, the result is satisfied.

Development of Risk Index of Uninterrupted Traffic Flow According to the Occurrence of Fog

The driver’s visibility is degraded when weather conditions deteriorate, which affects the traffic flow and induces traffic congestion or accidents. In particular, traffic accidents can be?led to chain reaction collisions, with high rate of fatality, when fog occurs in contrast to other weather factors that may restrict visibility. For the development of a traffic risk index, a deviation of the vehicle’s speed was set for the traffic risk index by referring to previous study results. In addition, factors that affected the deviation in a vehicle’s speed were selected as independent variables based on the traffic flow analysis during occurrences of fog. The visible distance, traffic volume, and speed were selected as the independent variables to estimate the optimal parameters in the regression model. The traffic risk index model during occurrences of fog proposed in this study is an exponential model, with the visible distance and the traffic volume defined as independent variables. According to the study model, traffic risk increased as the visible distance decreased and the traffic volume was lower. Thus, the visible distance that can affect traffic flow during occurrences of fog can be determined in the future based on the results of this study. The study results will be expected to contribute to not only traffic safety improvements, but also the facilitation of traffic flow as drivers and traffic operation managers intuitively recognize the level of risk.

Characteristics, Impacts and Risks of Dammed Lakes Induced by Debris Flows at the Wenchuan Earthquake Areas

After the Wenchuan Earthquake, many large-scale debris flows blocked rivers, generated dammed lakes, and produced outburst flood at the seriously hit areas. This paper mainly discussed the formation, outburst, impacts and risks of debris flow dammed lakes. The field investigation showed that the dammed lakes were created by debris flows from gullies and hill-slopes as well as the combination of debris flow and landslides, and also distributed along rivers step-by-step. The height of dams and the length of dammed lakes along river channel varied from 4 m to 18 m and from 400 m to 5000 m, respectively, and the reservoir capacity of dammed lakes were from 1.5 × 105 m3 to 3 × 106 m3. Due to geomorphological impact, dammed lakes commonly partially outburst along their front of debris flow deposition dams (1/4 - /3 outburst) or the suture between debris flow and landslide, and hardly completely outburst. Moreover, the subsequent debris flows continuously increased the magnitude and height of dams, not only increasing the stability of a single dam, but also improving the risks of outburst flood induced by intensive rainstorm. Dammed lakes produced steep rage in the sites of dams with the 4% - 9% of slope and rapidly raised river channel in the upstream due to a mass of alluvial sediment. As a result, the landscapes of step-dams and step-lakes dominate driver channels, significantly increasing the hazards of floods. Then the hazards, impacts and risk of debris flow dammed lakes along Min River from Dujiangyan to Wenchuan were analyzed. In order to mitigate dammed lakes induced by debris flows, the identification model of debris flow blocking rivers, the process of the formation, outburst and evolvement of dammed lakes, and the model of risk assessment for step-dammed lakes were strongly suggested to explore, and be used at the rivers of Min, Yuzi, Caopo, Longxi, Mianyuan, Jian, Shiting, Baishui and Jushui.

Systematic Reform and Risk Aversion in the Interregional Flow of Chinese Rural Labor Force --Wuhan Case Study

Based on Wuhan city investigation, this paper makes a positive analysis to the uncertainty of shifting rural labors to urban areas, and put forward thoughts and countermeasures to avert the risk of the interregional flow of rural labors.

Risk Assessment of Highway in the Upper Reaches of Minjiang River under the Stress of Debris Flow

The southwest mountainous area is a frequent debris flow disaster area in China, which poses a serious threat to the regional roads and greatly affects the normal traffic operation and the safety of residents’ lives and property. The debris flow risk assessment of highway can quantify the threat degree of debris flow to the roads. In this paper, from the perspective of villages and towns, taking the upper reaches of Minjiang River as the research area, four factors including road network density, highway disaster resistance capacity, population density and highway cost are selected, and the weight is obtained by using entropy weight method, and the debris flow vulnerability evaluation results of highway are obtained by weighted calculation. Four indexes of debris flow density, shape factor, relative height difference and annual rainfall are selected to evaluate the debris flow hazard of highway by using the information method. Based on the vulnerability and hazard evaluation results, the risk of highway debris flow is evaluated, and the results are classified and discussed. The results show that: the risk of debris flow on the upper reaches of Minjiang River is relatively low, the overall spatial distribution shows a trend of high in the East and low in the west, and the overall risk of township roads in Wenchuan county is the highest;The risk of debris flow is generally high within -10 to 30 km from the central fault zone of Longmenshan.

GO-FLOW法在蔬菜物流安全风险分析中的应用

为了辅助区域农产品物流安全风险控制,依据长沙地区的实际调研,分析了跨区域蔬菜物流作业流程,从系统可靠性角度出发,运用GO-FLOW法分别分析和评价了不完全冷链条件下和完全冷链条件下跨区域蔬菜物流安全风险水平,并对运算结果进行了比较分析,结果标明GO-FLOW法可以比较有效地分析与评价跨区域生鲜农产品物流系统安全风险水平,是对现有风险分析与控制方法体系的有效补充和完善.

基于GO-FLOW的航空冷链物流安全风险管理

在梳理航空冷链物流运输业务流程的基础上,应用GO-FLOW法测算了航空冷链物流运输流程的系统风险,并在GO-FLOW分析的基础上,识别分析出航空冷链物流运输流程各环节的风险程度。运算结果表明:航空冷链物流运输各环节中,停机坪装机与卸货环节、机场安检环节及两次地面运输环节都是显著影响航空冷链物流运输系统安全性的关键要素。最后,针对以上研究,结合工作实践,提出规避风险的相应建议。

基于GO-FLOW法的乳制品冷链物流系统安全性评价分析

为保障乳制品的质量,保证其在冷链物流过程中的安全性,辅助乳制品冷链物流安全风险控制,根据乳制品企业实际调研情况,分析了乳制品冷链物流系统的构成。从系统可靠性角度出发,构建GO-FLOW图,根据乳制品各环节不同的温度需求,设定该系统各环节的参数,运用GO-FLOW法对乳制品冷链物流系统进行了安全性评价。根据评价结果,对系统各环节的可靠性和故障率进行分析,找出了影响系统安全性的关键环节并提出了实际解决思路。结果表明,乳制品冷链物流过程中事故率和损耗率最高的系统单元是冷藏运输环节,其次是装车出库和短途卸车环节,可通过压缩这些环节的作业时间,避免"断链"现象的发生,提高系统安全性。

基于GO-FLOW的O2O生鲜海产品冷链物流系统风险评价——以上海厨易时代为例

在介绍GO-FLOW法的基本原理与分析冷链物流系统的运算步骤及规则的基础上,选取上海厨易时代作为公司示例,以鱿鱼的冷链物流作业流程为基础,对其各环节进行了可靠性评价,明确了全过程的关键环节和薄弱环节,并进行了改进,降低了损耗等风险,提高了系统可靠性,保证了产品质量。

基于Massflow的达摩沟泥石流模拟与危险性分析

达摩沟小流域历史上曾发生泥石流灾害事件,造成较大人员伤亡和财产损失。目前,该小流域主沟堆积大量煤矸石,主沟两侧坡面堆积有较多崩、坡积物。为分析泥石流再次发生的可能性与危险性,在无人机摄影测量和野外现场调查的基础上,详细分析达摩沟小流域泥石流发育条件,基于改进MacCormack-TVD有限差分法,采用Massflow软件对10,20,50,100 a一遇4种降雨概率条件下达摩沟暴发泥石流的工况进行数值模拟,得到达摩沟小流域在不同降雨概率下的泥石流危险性。结果表明:①在此4种降雨概率下,大部分区域的泥石流流速维持在0~3 m/s,泥深保持在0~4 m的水平,而峰值流量最大可达19 m/s,泥深最大可达3.85 m;②在100 a一遇的降雨强度下,达摩沟高危险性地区占16.54%,中风险地区占49.27%,低风险地区占34.19%;③模拟结果较好地符合泥石流的时空发育特征,展现了降雨强度对泥石流运动的影响规律,可为泥石流的预警监测提供参考。

基于Massflow模型的西藏仁布杰仲沟泥石流运动特征分析

为探明杰仲沟流域上游的潜在物源在极端条件下形成泥石流灾害,对沟口建筑及G318国道的危害性。以实地无人机拍摄数据为基础,通过三维建模生成研究区高精度的数字高程模型(DEM),再利用基于泥石流运动深度积分的Massflow数值分析方法,模拟泥石流的运动过程。首先分别用两种模型(Voellmy模型和Manning模型)对已发生的泥石流灾害进行了模拟,将模拟结果与现场实际情况进行对比验证,选取了结果更精确地Manning摩擦模型并确定了相应运动参数,在此基础上对体积为3.0×105 m3的泥石流灾害进行了预测模拟评估。通过对模拟结果进行分析处理,划定了研究区内的四个危险区,为泥石流灾害的防治规划和设计提供了有效的参考依据。危险区A位于泥石流沟第一个弯道处,该区及以南区域,泥深和流动强度都较大,但该区域人类活动较少;危险区B位于第一个弯道与第二个弯道之间,危险区C位于第二个弯道处,这两个区域内泥深较大,局部区域流动强度较大,极端条件下,危险性相对较高;危险区D位于国道南侧,该区域流动强度相对较小,但流体在此区域易发生堆积,所以应提高公路下涵洞的排导能力。

企业数据跨境流动的风险防控研究

随着大数据经济的发展,数据已经成为各国竞相争夺的数字资源。通过分析企业数据的内涵及特征,根据我国企业数据跨境流动现状,探讨了企业面临的内部数据合规管理体系不完善、数据监管机构不明确等难题。目前许多国家就数据跨境流动提出了解决方案,在此基础上通过建立系统性跨境数据流动法律规范体系、加强国际合作等方式、设置独立的数据监管机构,提升我国数字企业核心竞争力,降低开拓境外市场的合规风险。

基于灾害演化网络的泥石流风险评估方法研究

为准确地进行泥石流灾害演化风险评估、关键节点的定量识别,构建了基于灾害演化网络、结合随机过程的风险评估模型。通过构建灾害演化网络分析灾害链演化规律和灾害节点的影响程度,引入概率随机分布描述致灾节点发生概率和灾害节点的可能性,并将致灾节点发生概率,灾害节点发生后的影响程度和发生可能性进行耦合,识别灾害网络演化关键节点。将该方法应用于四川汶川板子沟地区泥石流后,结果表明:在四川汶川板子沟地区泥石流灾害演化中,风险控制的关键点分别是阻止泥石流入侵居民聚集地,减少交通受阻和救援受阻,与实际救援现场情况相符。研究结果可以为更有效地进行泥石流灾害应急救援提供一定的理论支撑。

Risk Control of Transmission Line Overload for Wind-Integrated Power Systems

With the rapid development of the wind generation,uncertainties of random wind and load bring some inevitable impacts on the security of power system. Once the uncertainty causes line power to exceed its limit, line overload will occur. The paper presents the risk control of transmission line overload for windintegrated power systems. Firstly, a risk control model of line overload is proposed considering the uncertainties of loads,generator outputs and wind powers. The generation cost and security level of system associated with overload can be optimally controlled. Then path following interior point method is employed to carry out the optimal control. Finally the simulation is made on the modified IEEE-30 bus system. Results show that the risk of line overload is effectively reduced through the optimization of control variables.

数字经济时代数据安全风险防范体系之构建与优化

随着人工智能技术的发展,全球进入“数据驱动”时代,数据流动创造价值的同时也带来日趋严重的安全危机。针对以数据滥用、数据泄露、数据污染为代表的数据安全事件,亟须通过建立全面、科学、有效的数据安全风险防范体系加以解决。然而,数据的法律属性与权利归属在理论上尚未廓清,数据流通边界的界定、数据安全综合防御机制的建立、公权与私权的博弈、数据安全保护与数据开发利用之间的内在张力都在不同程度上影响和制约了数据安全风险防范体系的建构。通过明确数据共享的权责归属,健全数据流动安全保护机制以及建立数据全生命周期风险预警防御机制有助于深入探明数据安全保障的政策法制完善之路。