Experimental study on the influence mechanism of gas seepage on coal and gas outburst disaster

By using the self-developed triaxial servo-controlled seepage equipment for thermo-fluid-solid coupling of coal containing gas and the self-developed coal and gas outburst simulation test device, experiments to study the influence mechanism of gas seepage on coal and gas outburst disasters. The results show that: (i) gas seepage decreases the strength of coal containing gas and accelerates its failure process; (ii) under the same gas pressure, the confining pressure is larger, the more difficult the gas flows and the greater the intensity of coal containing gas is; (iii) in the process of coal and gas outburst, the greater the vertical ground stress is, the more powerful the outburst will be; (iv) the influence mechanism of gas seepage on coal and gas outburst disasters is as follows: firstly, gas seepage weakens the mechanical properties of coal body, which makes it much easier for coal and gas outburst to occur; secondly, on the same effect of external force, it will be easy to form a high gas pressure zone in the coal body under the difficult condition of gas seepage, and accumulate more gas compression energy, which is the energy source for coal and gas outburst, and it is also the main dynamic source to throw and grind the coal.     

Investigating the effectiveness of safety countermeasures at highway-rail at-grade crossings using a competing risk model

Introduction: Highway-rail at-grade crossings (HRGCs) are critical locations where a railway and a roadway intersect with one another. Crashes at those locations often result in fatalities and economic and social damages due to the impacts on both road and rail users. The main purpose of countermeasures at HRGCs is to permit safe and efficient rail and highway operations. Method: Countermeasures at highway-rail grade crossings (HRGCs) considered in this study include all traffic control devices and other warning and barrier devices at or on approaches to crossings. In general, active devices are commonly accepted as more effective countermeasures than passive devices. However, many of the previous effectiveness studies are either at the project level or were conducted without considering the before-improvement condition. This study focuses on the network-level marginal effectiveness of countermeasures on crash rate and severity levels during the 29-year study period from 1990 to 2018 by fully considering before-improvement control levels. A competing risk model (CRM) is able to accommodate the competing nature of crash severities as multiple outcomes from the same event of interest, which is crash occurrence in this study. Subsequently, CRM is used in this study as an integrated one-step estimation approach that investigates both crash frequency and severity likelihood over time. Results: The study findings indicate that adding audible devices to crossings already equipped with gates will result in a considerable annual decline in crash occurrence likelihood (0.25%). The same device installed at crossings already controlled by gates and flashing lights results in less reduction in crash occurrence likelihood of 0.14%. Moreover, adding a stop sign to the active crossing controls of gates, standard flashing lights, and audible devices will lead to a decrease in the probability of crash occurrence and severe crashes (injury and fatal). However, adding stop signs to crossings equipped only with crossbucks will increase the crash occurrence.     

Global climate change and the politics of disaster

The paper explores the potential political impact of global climate change and, more generally, of natural disaster. Because the affluent West has largely tamed the natural and the social domains, popular clamor for government to anticipate, prevent, and redress disaster increases. I delineate several consequences of the new politics of disaster.     

现代灾害、灾害研究与灾害学

本文系统分析现代灾害的特点；评述灾害研究及灾害学的历史与现状，预测其发展趋势；探讨灾害学的基本范畴，界定其学科体系的总体框架，对灾害研究及灾害学发展中的几个重要问题提出认识与建议。     

试论沙漠化灾害危险度评价因子体系

本文通过对国内外沙漠化灾害危险度评价因子体系研究现状的分析，从我国实际出发，根据沙漠化灾害危险度的基本内容，首次提出了沙漠化灾害危险度评价因子体系，并给出了相应因子的分级标准。     

贵州省自然灾害区域分异规律及分析方法研究

贵州省自然灾害严重，且种类多，区域差异明显。为了分析自然灾害区域分异规律，本文提出了灾害模数、灾害区域差异系数等概念，编制了贵州省灾害等级图。     

1993年江西省洪涝灾害分析

１９９３年江西省发生了较严重的洪涝灾害。本文阐述了灾情，从自然因素和人为因素两个方面，分析了造成洪涝灾害的原因；并对今后如何搞好江西省洪涝灾害减灾，提出若干看法与建议。     

国外减轻城市洪涝灾害新设施发展综述

近二十多年国外在减轻城市洪涝灾害设施方面发展很快,建造了各种新型的抑制暴雨径流的设施,可分为流域雨水贮留设施和流域雨水渗透设施两大类,本文主要介绍目前国外已经建成和计划兴建的这些设施的型式、规划设计步骤、引起的问题和管理维护方法,以及在我国发展这些设施的必要和可能。     

全息理论与灾害周期性

地球系统是宇宙系统的全息缩影，地球上的灾害和天体之间具有全息关系，同样有恒定的周期性。本文根据全息理论对灾害进行分析预测，并建议在灾害研究中应用全息理论．     

生态环境与洪旱灾害

作者将自然运动与人类活动、生态环境与气候结合起来研究，求索洪旱灾害之谜，着重探讨了其中多种生态环境因素。由大灾后的反思，找出灾害加剧的人为原因是：人中激增、生态危机、水利失修等，提出必须加强防灾减灾的对策研究。