Study On The Mechanism And Control Technology Of The Coal Mine Roadway Floor Heave

During the production of coal mines, when the roadway is excavated or influenced by extraction,the bottom board often shows a phenomenon of floor heaving.Dramatic floor heaving have already caused serious potential safety hazard for production down in the mine.Most of the supporting and protecting measures are targeted for the top board and two sides,neglecting the distortion of the floor board, which intensified the chance of floor heaving.Therefore,conducting research on the mechanism and controlling measures of floor heaving of the roadway has important realistic significance for the maintenance of the stability of the roadway and guaranteeing the safety of production of the mine. In this study,we adopted the method of combing the theoretical analysis and numerical simulation,and integrated specific Geological Engineering Environment of a certain roadway and conveyed in-depth research on the mechanism of floor heaving and different controlling measures.The main work and conclusions are as follows:(1)Through research and analysis of the influencing factors of floor heaving, we recon that the main influencing factors that lead to floor heaving of roadways are the physical and mechanical property,stratum stress and strength of support and protection and the sectional form of the stratum;according to the shape of damage of different bottom board,conducted analysis on the features of the floor heaving.(2)Through research on the shape of damage of the bottom board of the roadway,established the mechanical model of the loss of stability of the bottom board stratum and divided the distortion into 3 main parts:active damage part,pressure transaction part and passive pressure part;the rule of disposition of the bottom board stratum is that: the damage happens first in the active damage part and generates effect of force on the pressure transaction part, and the passive pressure becomes distorted and forms floor heaving with the pressure from the stratum of the pressure transaction part, and gets distorted on the overhead direction of the vertical roadway and forms floor heaves;establish the mechanical model of the supporting rectangle lamina of the bottom board on the four sides, and select unit width of unit slices in the rectangle lamina,and under the pressure of vertical uniform distributed force and conducted deflection calculation for the unit slice under the the boundary condition of the clamps on the two sides and take it as the estimated value of the floor heave degree;analyzed main influencing parameters in the formula of floor heave estimation, and provided theoretical basis for bringing out the prevention and controlling measures for the floor heaves.(3)Adopted FLAC3 D numerical simulation software to conduct numerical analysis on the distortion of the surrounding rock of a specific roadway after it was dug open under specific working condition and geographical conditions,compare the floor heave distortion degree and the estimated floor heaves to verify the feasibility of the formula.After combining the main influencing factors of floor heave and analysis of the parameters in the floor heave estimation formula,we can bring out three different measures to manage the floor heaves,digging pressure releasing ditch, reinforcing baseboard rock bolt,and combining the grooving unload and united supporting of bottom board and the rock bolt.We conducted numerical simulation for each of these three treatment plans, and compared their control efficiency for floor heaves,and came to the conclusion that the plan of combining the grooving unload and united supporting of bottom board and the rock bolt can realize the best treatment result.