Applied Mechanics and Materials Vols. 675-677

Abstract: Through analyzing the structure of the alluvium and bedrocks, a discrimination method of main influence factors of surface subsidence was proposed, and the discrimination formula was put forward. Taking the overburden and ground surface of the large cutting height working face in Bin Chang mining region as the research object, the structure and location of key stratum and the structure of the alluvium was analyzed. Besides, through the surface monitoring, the parameters of ground movement and deformation was given, and the discrimination method was verified to be correct. Furthermore, using numerical simulation, the alluvium and bedrocks influences on the surface subsidence under different mining width were studied respectively; the ground movement and deformation characteristics under the influence of alluvium and bedrocks were put forward. The study has provided a basis for the prediction of surface subsidence under certain conditions.

Abstract: For the mutual disturbance several roadway excavation, it is difficult to support the roadway and damage is more serious, the original supporting scheme has been out of action, so the article by using the method of field test, theoretical analysis and laboratory experiments on the Yangcheng coal mine soft rock roadway destruction mechanism of in-depth study, based on the theoretical and experimental data measured results were analyzed, and according to the deformation analysis of Yangcheng mine lane, the failure characteristics and causes of roadway, also according to each drill hole core lithology and laboratory test, the basic physical and mechanical parameters, provides a reliable data of Yangcheng coal mine soft rock roadway failure mechanism, for similar geological conditions of coal seam mining also provides practical guidance significance.

Abstract: In combination with the geological conditions of Tie'er mining area in Tangshan coal mining, this paper not only analyzes the evolution of overlying strata structure in stope and the development law of overlying strata separation, also proposes a new continuous grouting technology with large flow and high concentration slurry. The industrial test showed that, when the grout-mining ratio of the whole mining area is 25.3%, the reducing subsidence ratio is 51.5%, the effect of reducing the surface subsidence is good. According to the chemical analysis of water quality ingredients of slurry, the test result showed, heavy metals contents in fly-ash slurry water do not exceed the standard, which has no bad effect on the fissure water in the bedrock.

Abstract: AH Wilson coal pillar was used widely as it’s simply, but it’s appeared large error for field implementation as its difference assume conditions, mine depth H and mine thickness m. AH Wilson coal pillar formula was studied precisely by in-site stresses test and numerical simulation analysis for N3-5 top coal caving working face of CHANGCUN coal mine in Lu’an coal district of China, then modified AH Wilson formula was put forward as L = 0.008mH + 8.4,then the precise coal pillar size 18m was used in filed implementation, filed testing proved coal pillar size was reasonable.

Abstract: Taking the filling tailings of Gangli iron mine as the experimental slurry, this paper use the orthogonal design method to design the experimental scheme to study the influencing rules of cement-sand ratio, mass concentration and curing period to the compressive strength. Use the variance analysis to test the results and the adaptive neuro-fuzzy inference system to establish a prediction model of compressive strength. The results showed that the cement-sand ratio was the most important influence factors on compressive strength and those factors have similar influence. The GA-BP model prediction has high accuracy rate of 95.1% and provides an effective model and method for prediction of compressive strength of cemented tailings backfill.

Abstract: The molten blast furnace slag (BF slag) is discharged at the temperature of about 1400-1550 °C, which contains a large amount of heat. At present, water quenching is the main technology to treat the BF slag, but this method not only consumes a huge amount of water, but also fails to recover the waste heat. Compared with water quenching, the dry centrifugal granulation has obvious advantages. There is no water consumed and the waste heat can be recovered efficiently, thus this technology has great potential. This technology mainly contains two processes: the granulating process and the heat recovery process. The present development statuses on those two processes are summarized respectively and the prospect of dry centrifugal granulation technology is forecasted.

Abstract: Coal mining and filling connection is very fast in continuous mining and filling working face. How to build airtight walls at ends of filling stope drift efficiently is one of the bottleneck problems, which restricts production improving in continuous mining working face. This paper presented a design idea of the rapid prototyping mold bag wall, analyzed its structure, did much research and finally provided the design. Field application showed that it improved construction efficiency and reduced cost.

Abstract: Smelting slag from mineral process and blast furnace process to vanadium titanium magnetite is a kind of precious secondary resource in which TiO₂ content is higher than 20%. Taking titanium-bearing blast furnace slag in Panzhihua region as research object, this paper analyzes four factors that affect the leaching rate of Al and Fe. The four factors are reaction temperature, reaction time, acid concentration, and the ratio of acid and slag. The conclusion drawn from hydrochloric acid leaching experiment is the factor that causes greatest effect to leaching rate of Al and Fe is reaction temperature, then reaction time follows. Acid concentration and the ratio of acid and slag cause insignificant affect. Appropriate leaching condition is 5h reaction time, 5mol/L hydrochloric acid concentration, 90°C~100°C reaction temperature and 1.2 the ratio of acid and slag. Max leaching rate of Al and Fe is 78.5% and 65.8% respectively.

Abstract: For the issue of fault impact on the height of water-flowing fractured zone, the study worked out several damage heights of superincumbent stratum under the influence of different dip angles faults. The research shows that small angle fault influence area is apt to develop a wide range of the plastic zone,and the water-flowing fractured zone of high-angle fault influence area is apt to increase along the fault surface and breakover the aquifers of coal seam roof and floor.

Abstract: In order to research the law of mine pressure and roof control in shallow buried coal seam, based on a comprehensive summary of mine pressure theory, technology application, engineering practice, summarized research results and status, analyzed research shortage, proposed research proposals. The results show that:1“short masonry beam” and “step beam” structure mechanical model and “key stratum in shallow seam theory” has provided theory basis for coal seam roof control shallow guidance. 2Rock and soil (bedrock and alluvium) coupling mechanism, loose layer dynamic structure theory," coal mining, water retention, ecology conservation, subsidence control" optimized portfolio on management theory and technical system of is the required research direction. 3Sichuan, Yunnan, Guizhou, representative of southwest mountainous shallow buried coal seam mining pressure research is conducive to development of mining pressure theory system.