Study on factors affecting abnormal mine pressure of large mining height fully-mechanized mining and support adaptability

In order to determine law of large mining height and adaptability of support in Shendong Mining Area, the field measurement was carried out by the working resistance of support and macroscopic mine pressure. Based on three main functions of support, protection and mining, the fuzzy mathematics method was used to quantitatively evaluate the support adaptability. The results show that there are two different types of mining pressure in the large mining height of Shendong mining area. The pressure step distance of Bulianta coal mine and Yujialiang Coal Mine is 14.3 m and 11.4 m respectively, and the rib spalling distance is generally less than 100 mm. The support overrun ratio is about 1%, the quantitative calculation of the adaptability of the support is good; the periodical pressure of the Bultai coal mine is high (the overrun ratio is 51.6%), the frequency of the pressure is high (the periodical roof weighting distance is 7.8 m), and the range of the rib spalling and the roof caving is greater than 1 000 mm, the quantitative evaluation of the adaptability of the support is extremely poor, and so the large mining height coal mining method must be replaced with the top coal mining. Quantitative evaluation of the adaptability of the support is extremely poor, and the mine pressure must be changed as abnormal mine pressure. Broken roof, mining layout, “isolated island” coal pillars and complex geological structures in the gob are the main causes of abnormal mine pressure.