Study On The Mechanism Of Coal Seam Floor Failure And Water Inrush Under Imbalance Water Pressure

The coal resources is the most major energy in China. Water inrush through coal seam floor is the main reason what restrict safety production. Especially along with the upper part coal is drying up gradually in our country, mining deep coal seam has to be done sometime, while the problem of water inrush through coal seam floor become more serious. Meanwhile it is harder to water drainage and mining above aquifer. Therefore the good water resisting ability of aquifuge in floor is the key factor for safety production. It means a lot on both theoretical and practical side to research the break destruction rule of aquifuge in floor by mining and water pressure.This article pointed out that the basement of Northern China type coal field, water exists only in local region of Ordovician Karst fissured aquifer, given water region has imbalance water pressure, and role in their overlying water impermeable layer. And also for the first time imbalance water pressure has been divided into four types of forms: Scattered punctates water pressure role, Trend banded water pressure role, Tendency banded water pressure role, Facet water pressure role.Using software FLAC^3D to carry out simulation calculation of coal seam floor failure under Facet, Trend banded, Tendency banded, by comparing with balance water pressure mode simulation calculation, it can be concluded that imbalance water pressure destructive effects on the impermeable layer is smaller than the balance water pressure destructive. At the same time, using FLAC^3D to do numerical test of mining width of the face and floor damage with mining the correlation, it can be concluded that the relationship between the two is not just a simple linear relationship, but a critical face mining width. When the actual mining width is less than the critical width, the depth of coal seam floor damage is linearly increased along with the wide face increasing; when the actual mining width go over the critical mining top, The correlation between mining width and floor mining action with the depth of damage is not obvious. In addition, using numerical simulation to do simulation calculation of Impermeable floor lithology combination with damage to the relationship between Impermeable layer, it concluded that the anti-destructive of hard rock is higher than the anti-destructive power of anti-soft rock, from the mechanics point of view, and pointed out that the mines should be established harm prevention and treatment of water in the area of soft rock and hard rock comprehensive evaluation criteria. In the end, using 10,409 coal face for the engineering as background, using numerical simulation methods backplane simulation Impermeable layer destruction, and compared with the measured data, results, it shows that the simulation results can be guidance to safety production and have values to practical application.