Study On Stability Classification Of Mining Roadway Surrounding Rock And Its Control In Wuhai Mining Area

The stability classification of roadway surrounding rock of is from the view of engineering application. Through a comprehensive analysis of the roadway surrounding rock strength, rock mass integrity, rock mass structure and other conditions, to determine the stability level of surrounding rock. The purpose is to offer a basis for the design of roadway support. There are a lot of indicators affecting the stability of the roadway surrounding rock, and mutual connection exists between the indicators. Some qualitative indicators are sometimes difficult to quantitatively describe, so the selection of indicators has some subjectivity and uncertainty. To select a group of reasonable indicators is the key to the classification effect of roadway surrounding rock stability. Therefore, on the basis of roof structure and other comprehensive factors, this article research on the stability classification of roadway surrounding rock and its control technology in Wuhai mining area.The field survey shows that in Wuhai mining area the roadway is mainly using bolt support. There are great differences in supporting situation among different mining areas. The stability of roadway surrounding rock mainly depends on the stability of roof. According to the stratigraphic age of coal seams, geographic distribution of coal fields and mining areas, the primary coal seams are preliminarily classified.On the basis of preliminary classification of the primary coal seams, using theoretical analysis method to research the sedimentary environment and coal-forming pattern of the primary coal seams, and obtaining two kinds of coal depositional environment. According to the change of coal-forming sedimentary environment, three different types of roof structure can be identified. Then, attempts are made to classify the roof structure of the investigated primary coal seams. Additionally, the stability of the roof with various structures is analyzed.Using the UDEC numerical calculation method, this paper selects two indicators to investigate the stability of the roof with various structures, the distance of the roof stable strata to the coal seam and the number of the interlayers within the roof. With the changes of the above two indicators, the changing characteristics of the interface sliding sphere and bed separation development depth are derived, offering a basis for the quantitative analysis of the stability indicators for the roof structure.According to the geological data of coal mine and the physical and the results of mechanical properties test, five indicators are chosen, the distance of the roof stable strata to the coal seam, the number of the interlayers within the roof, uniaxial compressive strength of rock sample, the ratio of immediate roof thickness to mining height and initial caving interval of the immediate roof.Each indicator is quantified by mathematics method. Finally the stability classification of roadway surrounding rock is derived.According to the supporting situation acquired by field survey, combined with roof structure and stability classification result of roadways, an analysis of the deformation and destruction mechanism of roadway with different roof structure is conducted. And corresponding surrounding rock control technology is put forward.Finally, observation of the law of ground pressure is performed in Limin and Laoshidan coal mine. The observation results show that the roof structure plays an important part in surrounding rock control technology of roadway, and through optimization of support scheme the surrounding rock control effect is improved.There are 30 figures, 24 tables and 78 references in this paper.