Applied Mechanics and Materials Vols. 204-208

Abstract: The supervision system of hazardous chemical based on the WEBGIS technology is constructed, which displays the reality of the situation and simulates the accident consequence of security risks ( including major risk sources ) to the user in the form of map, realizes the registration of hazardous chemicals, enterprise qualification examination, administrative licensing of hazardous chemical construction projects, and investigation and rectification of the potential safety hazard in hazardous chemicals enterprise as well as management and supervision in other related business process through information means, and improves the ability of supervision and emergency rescue in chemical safety production. It has an important significance to prevent and control the major hazard. This paper introduces the supervision system of hazardous chemicals and the structure, database design, and system application of the supervision system.

Abstract: Debris flow disaster occurred frequently, at the same time it covered a wide area in China. Through statistics analyzing debris flow disaster data from 1914 to 1999, obtain that debris flow hazards mainly distributed in the east longitude 100-110°, 25-30°north latitude and 30-35°north latitude in China. This region is mainly affected by subtropical climate and central Asia humid tropical monsoon climate, such climate have little rainfall in winter but intense rainfall in summer, due to the complex topography and different monsoon circulation, the frequency of debris flow occurrence in this area is much higher than other areas. After the earthquake in May 12, 2008, the slope material structure are destroyed which in turn provide adequate loose clastic-sediment for debris flow to initiate, several years later the loose clastic-sediment may reconsolidate again and reach new balance. Compare the frequency and scale of debris flow before and after the earthquake, know that after earthquake the frequency and scale of debris flow are much serious than the events occurred before earthquake, then gradually tend to stable. Based on these phenomena could predict the scale and trend in the future, at the same time it could provide reference for debris flow prevention and reduction, and then reduce the loss that caused by debris flow hazards.

Abstract: The nonlinear finite element method (FEM) was used in the paper by using LS-DYNA software to numerically study the failure mechanism of light steel columns under fire and explosion. The constitutive model under the combined effects of fire and explosion was established, and the numerical simulation analysis of the columns under combined effects of fire and explosion was performed. The results showed that the failure modes of the mentioned columns were all bending shear failures. The deformation diagrams of the column under the blast and different temperatures, respectively, were proposed and this will provide a foundation for establishing the failure modes and the simplified calculation method. According to the relationship between rotation angles at the ends of the column and temperatures, the damage index of D was proposed in this paper for the evaluation of the damage level of the simulated light steel column.

Abstract: In the hazard assessment of debris flows, the determination of weights of assessment indices is both important and difficult. Base on the difficulty in defining weight values, the catastrophe theory is used in the hazard assessment of debris flows, and the advantage of catastrophe theory in the multi-rule assessment is used to avoid the subjectivity of artificial weights. The proposed method is conducive to calculation and does not necessarily define the weight of evaluation indices so that the influence of subjective factors on assessment can be minimized. The assessment results indicate that new assessment method is reasonable and feasible, and it provides a new idea for hazard assessment of debris flows.

Abstract: The time-dependent effect for reinforced concrete T-shaped section beam exposed to fire was analyzed in this paper. Based on fire test of building structure home and abroad, combining crack criteria and nonlinear constitutive relationship, finite element analysis method was put forward. Analyses were performed to study the influence of several parameters on the fire resistance of reinforced concrete T-shaped section beam exposed to the IS0834 standard fire，which it included fire time and ratio of reinforcement．The studied results indicate that: section distribution gradient width has a gradual expanse from outside to inside with extension of fire time, time-dependent curve of deflection for reinforcement concrete T-shaped section beam fundamentally decreased linearly with extension of fire time; deflection is nonlinearly increased with load ratio; oblique crack is liable to occur relative to vertical crack.

Abstract: The most ancient buildings of China are formed by wooden elements, such as columns, beams, so they are prone to fire and are difficult to fire control due to the lack of fire channel. The cause of the fire includes two aspects of human and nature. The basic countermeasures of ancient building fire mainly include display in such aspects as opening fire channels, doing well the construction of fire water sources, the use of advanced fire protection technology, managing the fire of life and maintenance strictly and so on. Meanwhile, handle the relationship between fire and protection of cultural relics.

Abstract: With the increase of the span length of bridge, the wind field characteristics at bridge site play crucial role for the safety of bridge. The present paper discusses the results of a numerical simulation of the wind flow over mountainous area called Aizhai, located in Hunan province, where a super long span bridge with main span of 1176m will be constructed. The results indicate that it is inappropriate to describe the mean wind velocity profiles by power law using the same roughness exponent along the span wise direction in the mountainous valley terrain. The speed-up effect and the significant change in wind direction of the mean flow were observed, which provide the information necessary for determining the design wind speed such as for a long span bridge across the valley.

Abstract: The accident occurred on two points, one is thing’s insecure state, and the other is human's insecure behavior, the majority accidents cause of gas storage and transmission facilities are initiated by person's behavior factor in China. Furthermore, learning from the knowledge of psychology, and explore the artificially induced factors, from conduct of practice, occupational structure and cultural level, relationships, social pressure, managers own behavior. The paper put forward the measures and countermeasures which is accord with China's gas storage and transmission actual, and superintendents would promote humanities concern, and pay great attention person's life value.

Abstract: Coal-gas outburst is a kind of complex disaster induced by engineer operations in the process of extracting or developing in coal seams. According to the theories of gas seepage and deformation of coal or rock seams, taking consideration of the heterogeneity property of coal or rock materials in mechanics of materials as well as non-linear permeability characteristic of coal or rock materials in the process of deformation and fracture, SPH algorithm of LS-DYNA software is used to numerically simulate the coal-gas outburst induced by development in coal seams. Simulation results represent the whole process of coal-gas outburst from the growing, extending and connecting of cracks to final outburst under the impact of gas pressure, ground stress and mechanical properties of coal-rock. The nonlinear nature of the mutation of outburst induced by gradual destruction of the coal or rock materials under the influence of developing operations is revealed, including the evolution of the stress field in the rupture process of the coal or rock material. This provides a theoretical foundation for further understanding the mechanism of coal-gas outburst as well as preventing outburst technology.

Abstract: The Wudongde reservoir area 3D visualization geological disaster information system is designed in this paper, based on the superiority of Skyline software and Skyline TerraExplorer API. It consists of two parts: retrieval browsing system and spatial analysis system. Retrieval browsing system has several functions, such as displaying, browsing, information retrieval, data statistics, querying, searching and printing. Spatial analysis system sets the core modules, including spatial calculation, terrain analysis and flood-inundated simulation. It is verified by application that this system can be used for displaying 3D scene of the Wudongde reservoir area terrain, providing decision support for the governor, reaching the design requirements wholly.