Study Of Plastic Flowing Deformation Mechanism And Control Technology Of Floor Heave In Roadway

Most deep resource mining is confronted with a three-high and one-disturbance geological environment, where rocks which have hard-rock characteristics in shallow mining show soft-rock mechanical characteristics such as high pressure, large deformation and difficulty in supporting in deep mining. The deformation control of surrounding rocks is the key problem in deep mining. To solve the difficult support problem of deep soft rock roadway, we should turn to the deformation mechanism and prevention measures of floor heave firstly. The plastic flowing deformation is a common type of floor failure in deep soft rock roadway.Based on the plastic limit analysis theory and geotechnical material slip line theory, this paper studied two possible failure modes of plastic flowing deformation of roadway floor in the situation where the vertical stress is the main stress, and then clarified the plastic flow range, stress distribution and displacement evolution of floor. After that, it obtained the expression of floor bearing capacity in limit state, and explained deformation modes of the whole floor lifting and floor center bulging.Combined with numerical simulation, the thesis studied the major factors affecting the plastic flowing deformation of floor and pointed out that the much thinner the lining thickness of roof and two sides is, the much larger the roadway span or the much higher the vertical pressure is,the much closer the mode of plastic flowing deformation is to the floor center bulging.By using the self-developed deformation measurement system of roadway deformation to observe the full plastic flowing deformation and failure process of floor rock and to analyze qualitatively and quantitatively, we discovered that local shear failure occurs firstly in the loading area and expands towards the middle of the model with the increase of load, and when local shear failure forms a continuous sliding surface, plastic flow occurs continuously. The displacement evolution laws of different sections were studied. Comparing the results with those of theoretical studies, it turned out that plastic zone distribution and deformation mode of floor plastic flowing deformation derived from model test were basically accorded with the plastic zone and displacement mode of Hill-like mode by plastic limit analysis.Based on the above, the three kinds of supporting technology for direct control of the bottom board, which are floor anchor, anti-slide pile and inverted arch were studied. The results showed disposing anti-slide pile perpendicularly to roadway floor can restrain the plastic flow deformation of floor; laying inverted arch can improve the ultimate bearing capacity and it can provide maximum support resistance when the radius of inverted arch is half the width. Supporting parameter design methods were put forward, which provide reference for traditional support design.Finally, taking the floor heave of HuaFeng Coal Mine in Shandong New Energy for example, a reinforcement scheme for winch room foundation combining anti-slide pile with floor anchor was proposed.Site monitoring results showed that the joint reinforcement scheme can control the floor heave effectively. Therefore, applying anti-slide pile in slope reinforcement engineering to control plastic flowing floor heave is feasible.