Applied Mechanics and Materials Vols. 580-583

Abstract: The paper studied the driving blasting mechanism and blasting parameters in working face, in order to improve the advance rate of blasting mining face in Liangzhuang mine. The research results show that taking the air column interval charging structure can reduce the peak pressure on the borehole wall, change the distribution ratio of explosion energy, decrease the smash district radius and increase the effect of secondary stress wave. To improve the energy utilization efficiency was improved in this structure, the consumption was reduced by 35.3%, the cyclical footage from 0.8m to 1.2m and crushing effect is obvious.

Abstract: The surrounding rock deformation of pedestrian roadway was serious under the influence of the working face. And it has affected the safety and normal use of roadway. To ensure the long-term stability of the pedestrian roadway surrounding rock and increase the coal recovery rate of working face, the paper studied the position of stopping line of 1203 working face by numerical simulation. The results show that setting 115m wide of security coal pillar between 1203 working face and pedestrian roadway that the area of stress concentration near the working face has less effect on the pedestrian roadway could better control the surrounding rock stability of the pedestrian roadway and meet the need of the long-term normal production use. It narrows the width of security coal pillar, increase the coal resources recovery rate and achieve the better economic benefits.

Abstract: 3^# coal seam of Daning coal mine is outburst,thus severely restricting the safe production. Based on the analysis of gas emission sources and the logical drainage parameters, firstly, Daning coal mine arranged some drilling fields, then utilized the VLD-1000-type rig to drill boreholes, achieving the integrated gas drainage of the coal seam and goaf. Finally, there is a test on the drainage result. The results showed that, through this kind of integrated gas drainage technology, the highest value of gas pressure in the coal seam reduced to 0.63MPa from 1.95MPa after twelve months’ drainage, and the gas drainage rate of the whole mine reached 77.6%, achieving efficient use of gas clean energy.

Abstract: The responses of tall buildings under wind loads in hilly terrain are remarkably different from that in flat terrain. Wind load codes can’t work efficiently or directly to calculate the wind-induced vibration of tall buildings in hilly terrain. Utilizing some wind tunnel test results of wind field in hilly terrain and pressures on tall buildings, the access to response of tall buildings on hilly terrain were provided. Some effects from hill characteristics to building responses were discussed.

Abstract: For the effective prevention and control of mine bumps, or to a certain extent, to reduce the loss the losses caused by impact ground pressure accident,thin-walled components are proposed to be applied as a scaffold components in roadway supporting. Components impingement is reflected in the component crushed process ,in which the impacting energy absorption and crushing space provide certain amount of energy to free up space. The energy absorption characteristics of different configuration thin-walled components has been simulated with ABAQUS finite element, such as the conventional square,regular hexagon, round and origami square, regular hexagon etc,.and the results showed that: (1) The problem of conventional components is larger load fluctuation coefficient. Origami component is a kind of perfect impingement components ,as it can reduce peak loads and the load fluctuation coefficient effectively. (2) Under different ratios width-to-thickness, components can have different deformation modes, but the relationship of peak load and wall thickness is near linear and has nothing to do with the deformation modes. (3) The component can have a relatively lower crushing peak load and load fluctuation coefficient and relatively higher specific energy absorption,if given a suitable diamond concave angle. impingement components using combined with existing supports can make the existing supports to become top beam impingement support , mudsill impingement support ,two sides impingement support and impingement hydraumatic support and so on.

Abstract: Frame structure building is widely used for its advantages of flexible space, light weight, saving material, building plan can be flexibly arranged and so on. However, researches on frame structure built in the water in cold areas, under horizontal ice pressure, are very few, and there is also no ice pressure calculation method for this structure form. Combining with the damage phenomenon of Jintaizi fishing floor engineering, analyzed the causes of freezing damage from ice pressure, temperature joint, structure form, and put forward a concept of ice pressure influence width for frame structure under the effect of ice. This article provides a reference for ice pressure calculation and the design of frame structure buildings which built in the water.

Abstract: The developing trend of large scale curtain wall structure system is monolayer cable net glass curtain wall, so it’s important and necessary to study the corresponding calculation method and mechanical properties under fire conditions. The changing rule of the displacement and the maximum cable force with the temperature was analyzed by making series of numerical calculations, and the principle for determining critical temperature was deeply discussed upon the basis of the numerical simulation results. The critical temperature table considering different spans, grid dimensions and cable diameters is given, and the influence on critical temperature has also been studied when initial prestressed force of vertical cable is relatively small. Some suggestions are proposed finally.

Abstract: The pregnant and sliding mechanism was firstly compared between Vajont and Qianjiangping large rock landslides, which happened in the chair-shaped cataclinal bank slopes. And then the essence of the landslides occurred was deduced. The pregnant and sliding process of the landslides was showed two stages. First, after the first impoundment of the reservoir, the soil and shallow rock at the front of the landslides were slipped and then caused posterior margin of the deep latent sliding surface cracks. So the groundwater supply condition was significantly changed. Second, with the rapidly increase of the groundwater recharge, its pressure on the front of the landslides was also rapidly rise to the critical value which the landslides occurred. Afterwards, the stability mechanical model of the chair-shaped cataclinal bank slopes and critical value formula of the groundwater pressure were established on the basis of the stability mechanical model of general chair-shaped cataclinal slopes, added reservoir water level which was a dynamic load. While working procedures to determine the groundwater pressure was put forward. Last, the theory was certified validity take Liangshuijing rock landslide of the Three Gorges Project area as an example and the monitoring methods and control measures for the landslide were proposed.

Abstract: To combine expert scoring and rough set two kinds of subjective and objective methods, avoiding the indicator weight value is zero, making the expert scoring more efficient, objective. Using the expert scoring method based on rough sets in determining evaluation indicator weights of open-pit dump landslide. Slope density, cohesion, internal friction angle, slope angle, slope height, pore pressure ratio were selected for evaluation indicators of dump landslide. First of all, according to the landslide data collected, to calculate the importance sort of evaluation indicators of the dump landslide based on rough set theory. Then, scores of each indicator corresponds to a certain interval, five relevant experts were selected for scoring. Finally, the weight of each indicator was determined based on the average score. We can know from results, slope angle has the biggest influence on the dump landslide, followed by pore pressure ratio .Slope height and slope density have the minimal impact, which is coincidence with the actual situation of the dump, it shows that the method is more rational and effective .

Abstract: Ignition temperatures of common radiation cargo in irradiation room were measured through the experiments, minimum ignition temperature is 210 °C. In order to discuss the temperature variation and temperature field under stuck radioactive sources, the fire scenario was presented and simulated by FDS. The results show that temperatures rise rapidly when stuck radioactive source broke out within an hour. As the growth of the time, temperatures in irradiation room are rising, but the rising rate is slowing. The temperature field in the irradiation room tends to be the same after three hours. The stuck radioactive source occurred after 2.4 days later, local temperatures can reach 210 °C, and radiation cargo may be ignited.