Study On Laws Of Mining Pressure And Control Of Fully Mechanized With Soft Floor In Medium-thickness Steep Seam

Because of strong compression with tectonic movements, the angle of coal seam becomes steepened, fault and fold increases, joints and cracks are generally more developed, and occurrence conditions of coal seams change greatly during the formation of steep seam. And then in mining process usually occurred roof fall. If the floor is soft rock, it is easily to slip to destroyed floor when the support resistance is not in place. What's more, as the angle of coal seam is too large, and the support bracket with less capacity, it will inevitably lead pillar or hydraulic support to decline and dumping during the mining process.This paper takes the 4155 of the longwall for large inclined angle Fully-Mechanized face of the HuaShan Coal Mine of PanZhiHua mining industry group as the project background. Through theoretical analysis, computer simulation and the scene actual research technique and so on, studied on ground pressure feature and surrounding rock control technology in the steep seam mining with soft floor. Using relevant theoretical knowledge, study laws and parameters of roof strata movement in steep seam, such as the first roof caving span of the immediate roof, first roof caving span of main roof, and periodic weighting span of main roof; Building model of soft floor in steep seam mining, and using Winkler elastic foundation model to do mechanical analysis on it, eventually receive the critical force formula of floor slipping, and the optimal number of brackets in bracket sets is 4-6.Through numerical simulation, study on macro-mechanical behavior comparatively of different inclined coal seam at different times in the three-dimensional fully mechanized mining, receiving inclined fully mechanized face during the whole advance, the wended stress distribution in mining, inclined stress distribution, fracture morphology of surrounding strata and move feature of rock. Through analysis, we think that stress concentration factor and the plastic area becomes ever-reduced in front of rib following increment of coal dip angle; Area of stress concentration in inclined pillars also become smaller and smaller; Shapes of damaged area of surrounding rock gradually change from "saddle" shape to the parabolic arch.Through field measured, we receive laws of ground pressure behavior in steep seam mining; Based on the features of ground pressure behavior in mining, aiming at the disasters that turn up easily, it suggests measure of strata control, controlling technique of roof falling anti-down and anti-skid measure of hydraulic support and the controlling technique safety protection in working face.