Applied Mechanics and Materials Vols. 501-504

Abstract: The combustion performance of engineered wood flooring and intensive composite floor under the different radiation heat flux were experimented by cone calorimeter. Fire parameters were measured including the ignition time and heat release rate. Experimental results show that the ignition time of engineered wood flooring is much lower than intensive composite floor, and the ignition time are decreased with the increase of radiation heat flux. The heat release rate (HRR) curve has two peaks under the same radiation heat flux, and the first peak of the heat release rate of engineered wood flooring occurs significantly earlier than intensive composite floor. The heat release rate is increased and the first peak significantly ahead of time with the increase of the radiation intensity

Abstract: The position and role of the construction industry in the national economy is getting increasingly significant, though the safety situation of construction production is not optimistic as hazards is the basic cause of the accident as well as the necessity of the research of hazard management mode has been increasing. Based on the hazards of the basic theory from two aspects: the identification of hazards control and analyze the hazard management, obtained from the project before and after the project, project management of hazards management model.

Abstract: Gas explosion is a kind of harm partial load by accident, it is the main cause continuity of the collapsed buildings. Based on the gas explosion of a frame structure damage detection, this paper analyzed the characteristics of gas explosion and put forward problems when building structure design as well as the prevention and control measures of gas explosion.

Abstract: Establishing efficient evaluation system of the emergency ability of water emergency is of great importance to strengthen the emergency response ability to maritime emergency of government departments. According to the principles of establishing evaluation index, an evaluation system was proposed on AHP in the article. Then an evaluation model based on AHP and FCE was established, which provided scientific evidences for the emergency management of maritime emergency in the future.

Abstract: Many important nature evolution phenomena can be explained with Self-organized criticality (SOC) theory. SOC theory explains the tendency of large dissipative systems to drive themselves into a scale-invariant critical state without parameter adjustment. These phenomena are of crucial importance because fractal objects displaying SOC are found. This paper analyzes the characteristics of SOC theory, and then introduces basic principles of SOC theory in one-dimension model. Based on the self-organized criticality owned by the high-density pedestrian evacuation and even the trample event, this paper proposes the potential applications of SOC theory to explain the various phenomena in pedestrian evacuation from public buildings in unconventional emergencies.

Abstract: Nowadays, traffic accidents have become one of the ten major threats to human health, and reducing the damage to life and property has been the people's demands. Traffic accident analysis has its inherently regional difference. The main objectives of this paper is to conduct investigation and statistical analysis on the weather conditions, month, week, hour, road environment, the drivers age and driving-age of the accidents, based on the traffic accidents records of a Dalians transportation group from 2008 to 2012. According to the acquired statistics and countering the geographical and climatic characteristics of Dalian area, this paper put forward traffic accident prevention measures proposed for Dalian area:Timely safety education and training for the drivers, establishing enterprise safety culture and establishing and improving the safety management system of modern traffic.

Abstract: The progressive collapse of the buildings is an extremely harmful disaster, which always leads to serious loss of life and property. It has been one of the hotspots of the civil engineering study. The progressive collapse of the buildings includes a throng of questions: material nonlinearity, geometric nonlinearity, contact-impact problem, so there are still many problems need to be further study, In order to get a kind of method which is feasible, dependable and efficient, to assess structural progressive collapse-resisting capacity. The research of the assessment can provide a scientific basis for structural design, reinforcing and transforming old structures.

Abstract: A variety of coal pressure phenomena and coal fracture phenomena are relevant to the coal microcrack evolution, and the gas contained in coal seam makes the crack propagation more complex, therefore the disaster-causing fracture mechanism of coal containing gas urgently needs indepth study. It is found in previous studies, that coal, as a complex structure, when fractures, is not only influenced by its complex structure and mechanical properties of the coal matrix structure, but also influenced by the friction on the crack and the gas molecular force. In this study, it is further believed that in the process of crack propagation, crack tip constantly breaks into new interfaces with high surface energy, and on the new interfaces Van der Waals forces of gas molecules forms the gas adsorption film, which can reduce friction coefficient . The resistance to brittle fracture of coal decreases as the friction coefficient reduces, which makes the crack propagation further develop and accelerates the fracture process of coal containing gas. According to the results, the gas can reduce the macro-mechanical properties of coal and rock mass, which is consistent with previous study, therefore specialized research on the physical and mechanical parameters of gas-containing coal and its disaster-causing mechanism is in urgent need, thus practical production can be accurately guided and evaluated through these researches.

Abstract: In the presented paper is assessed fire risk of pellets made from spruce wood (Picea abies L.) without bark, processed by hot pressing without the use of additional chemicals. Fire risk was assessed on the basis of heat release rate (HRR), the specific carbon monoxide production rate (SCPR) and the time dependence of the induction period of spontaneous ignition on temperature. HRR and SPCR were determined on the cone calorimeter test performed according to ISO 5660-1:2002 standard. Samples were loaded by 20 kW/m² heat flux during the test. The maximum HRR was 229 kW/m² and average HRR was 55 kW/m². Maximum SCPR was 0.37 g/(m²s) and the average SCPR was 0.16 g/(m²s). The dependence of the induction period of spontaneous ignition on temperature was determined by a modified test performed according to ISO 871:2006 standard. Modification of the test procedure was based on measurement of the induction time period of the spontaneous ignition on temperature, and temperatures higher of 20, 40, 60, 80 and 100 °C than spontaneous ignition temperature. The obtained data proved an exponential dependence of the induction period of spontaneous ignition on temperature.

Abstract: Roads often run across various drainage basins in mountain areas which include complex geographic and geomorphic conditions. Highways in these areas have been frequently interrupted by debris flows. Without emergency management planning, such debris flows can lead to extensive life and property loss. Through analyzing the hazard effect modes and damage process along highways, we developed three key indexes, scale of debris flows, deposits on highways and river blockage, to describe the highway disasters quantitatively. According to actual investigation, we proposed new methods to determine the value of hazard indexes. Subsequently, we developed the assessment and mapping methods for highways safety by using hazard degree of debris flow. The hazard is graded into 4 grades as extreme low, low hazard, medium and high hazard level. Through applying this method, a case study was carried out on national highway G318 in Xiqu River basin. After analyzing debris flow hazard for the whole highway, the assessment results are consistent with the field surveyed data which indicate actual disaster situation. This hazard method can objectively evaluate the debris-flow hazard along highways, and is useful for highway reconstruction in mountainous areas suffering from active debris flows.