Applied Mechanics and Materials Vols. 256-259

Abstract: A bridge, which is located in the route of typhoon, is considered how to assure normal traffic use against strong winds. As one of the measures, wind barrier is proposed to be set on both sides of the bridge section for reducing wind velocity across it. In this study, an analysis by using CFX, a computational fluid dynamics program, is carried out to investigate the effects of wind barrier. The speed of wind is assumed as 60m/s. To find out an efficient design of the boards, different porosity ratios(r) of the boards is assumed for comparison. The result shows that wind barrier could reduce the wind speed across the bridge effectively.

Abstract: Based on present condition analysis of coal mine water disaster occurred in recent ten years, classification bases such as water source, water passage, water disaster form, economic loss and casualties caused, aging characteristics and spatial distribution relationship between coal seam and water source of the disaster are proposed. According to water sources, the disaster can be subdivided into natural and artificial source coal mine water one. According to water passage, coal mine water disaster can be subdivided into natural and artificial passage one. According to the spatial distribution relationship, it can be subdivided into roof, periphery and floor water inrush disaster. According to damage form, the disaster can be subdivided into normal temperature, abnormal temperature and corrosive one. Based on economic loss and casualties, the disaster can be subdivided into general, larger, great and special great coal mine water disaster. And according to aging characteristics, it can be subdivided into instant, hysteretic, gradual and skipping coal mine water disaster. Finally, typical characteristics of each disaster are analyzed preliminarily.

Abstract: Regional comprehensive disaster prevention and mitigation planning is to evaluate the disaster risk and disaster resistance capability of a region based on the investigation and prediction of existed or potential disasters in this region, and after that the planning will construct a comprehensive defense system to avoid or reduce the economic loss of disaster and improve the disaster prevention capability. Tanghai County comprehensive disaster prevention and mitigation planning evaluates disaster resistance of all units of county and disaster mitigation of disaster-prevention projects, and it emphasizes on comprehensive disaster prevention and mitigation planning in key regions. This planning will improve the disaster prevention capability of local government, reduces disaster risk and ensures the sustainable development of economic and environment for that county.

Abstract: To study the features of infrared radiation of concrete fracturing water seepage and water inrush process ,concrete is pressurized with no water press and water press to uniaxial compressive stress .The experimental results show seepage point of concrete block in the process of destruction of water inrush with different characteristics.The IR radiation of seepage point shows an rise in early term, then partial low temperature, and rise in late term.Before water seepage water pressure let heating increase slowly, when water seepage makes temperature drop low in the water seepage point and it‘s aslo the reason of concrete water seepage and water inrush come early .Base on the experimental results, the mechanism of infrared radiation in no water press and water press are analyzed,the difference between them also be discussed.The experimental results are useful for infrared remote monitoring and disaster warning on concrete projects.

Abstract: Adaptive Neuro-Fuzzy Inference System has the merits of high convergence speed, potentially better generalization capability, high prediction accuracy and definiteness of the training results, and it has been applied to inverse design of slopes and surface displacement due to coal extraction. By training and checkout the collected 19 examples of mining under water body, the optimum ANFIS modeling was established. ANFIS-based approach for the forecast of the height of transmissive fractured belt are applied to the extraction the No.Ⅲ ore body at Kangjiawan Zinc-Lead Mine successfully, some important conclusions are of great significance to the factual issues. All the experiences may be of greatly beneficial reference for the similar projects since then.

Abstract: Boilover is acknowledged as one of the most harmful fire in oil tank fire. A small-scale oil tank boilover apparatus was established to study the flame behavior during boilover process. Visualization experiments were also conducted to discuss the mechanism of boilover formation. The results indicate that boilover process can be divided into three stages: quasi steady combustion stage, boilover premonitory stage and boilover stage. The formation of boilover results from the reciprocity of bubbles and oil vacuoles generated by absorbing energy released from combustion reaction.

Abstract: A new type of small proportion double rod structure magnetorheological(MR) damper was manufactured in this article, and the damper performance test was taken on electro-hydraulic servo system. The results indicate that the damper is not only able to provide a large damping force, but also its adjustable coefficient is high. And the hysteresis curve is still good in a high-frequency vibration, so it has a good stability.

Abstract: The critical technology of Earthquake Early Warning (EEW) is determining the size of an earthquake and the predicted ground motion at given site, from the first few seconds of the P wave arrivals. Currently, there were two different approaches to the EEW magnitude estimation, the predominant period method and the peak amplitude method. However, both methods mentioned above had some disadvantages, such as significant uncertainty and saturation at great magnitude. To improve the results of magnitude estimation, a combined method using predominant period τc and peak amplitude of acceleration Pmax was introduced. Compared with the predominant period method and the peak amplitude method, the estimation standard deviation level of the combined method is 0.42 using NSMP strong motion data. The magnitude estimation results of the first three seconds P wave indicate that, the estimation precision of combined method is higher than those of the two methods, the predominant period method and the peak amplitude method, and the saturation at great magnitude is improved.

Abstract: In order to achieve the fire resistance performance of recycled concrete, four concrete tubular structure specimens were designed and tested under the high temperature. One of the specimens was made from normal concrete C20, one was made from recycled coarse aggregate concrete C20, and two were made from recycled coarse and fine aggregate concrete C20 and C40 respectively. The temperature field, the vertical displacement, the wall deflection and the fire endurance were comparatively analyzed. Results show that the rate of temperature increasing inside the concrete becomes smaller with the increase of recycled aggregate replacement rate. The temperature of specimens with recycled concrete is lower than that with normal concrete at the same position, the same force condition and the same fire condition. The load carrying capacity of specimens with recycled concrete is lower than that of the normal concrete specimen due to the bigger porosity of recycled concrete. The fire endurance decreases with the increase of recycled aggregate replacement rate in the specimens. With the increase of the strength of recycled concrete, fire resistance and fire endurance of the tubular structure decrease and the structure tends to fail in expansion under high temperature.

Abstract: The traffic safety in fog area along highway is a worldwide issue. Not only the cost of the injuries and deaths but also the cost of crash involvement by fog is quite large. The rationality and effectiveness of contingency plan for hydro-meteorological hazards is important on reducing the damage to traffic systems. Microscopic simulation models are now widely accepted as the most appropriate analytical tool for understanding traffic capacity problems and for assessing the effectiveness of ameliorative measures. Therefore, the authors have undertaken a simulation study to pre-evaluate the effectiveness of contingency plan in Henan highway network to ensure the effectiveness of traffic organization scheme under hydro-meteorological hazards in Henan highway network. This study illustrated how to assess the effectiveness of ameliorative measures using the microscopic simulation model. The results showed that real-time monitoring and dynamic traffic guidance can better enhance the efficiency of contingency plan.