Study On The Stability Of Wall Rock And Control Technology On Underground Mining

The distrubitions of the stresses, displacements and failure zones in the wall rocks are affected by underground mining. The stability of the wall rocks becomes weaker due to underground mining. It is important to realize the variations of stresses in the wall rocks for adopting reasonable support measures.In this thesis, the fully-mechanized coal mining with sub-level caving in high steep coal seams and the support technologies in lanes with thin coal roof are studied on the basis of TianZhu mining. Many resaeach finfings are acquired.The similar simulation test on work face using the fully-mechanized coal mining with sub-level caving suggests the movement and breaking of the roof are asymmetric in the inclined cut. The main roof caving can perform articulated roof beam in the inclined cut. It is divided into four parts from uphill direction to downhill direction. I is free caving zone, II is up arch-foot support zone, III is articulated zones, and IV is down arch-foot support zone.Numerical analysis are completed to study the distrubition of stress arch in the inclined cut in work face using the fully-mechanized coal mining with sub-level caving. There is stress arch upon the work face in the inclined cut. The down arch-foot is in the down coal seams and rocks in the inclined cut. The up arch-foot is in the roof coal seams and rocks in the inclined cut. The maximum principle in stress arch is higher than the rocks out of the stress arch. The stress arch is main support body. The load and pressure in hanging strata are carried to the down corner of the work face to perform support pressure near gate stull through the stress arch. The main mechnics feature is that the work face using the fully-mechanized coal mining with sub-level caving is in the low stress zones under the stress arch.The Flac and UDEC projects are used to construct geological model of the lanes with thin roofs. It is feasible to make lanes in this surrounding. The support technologies of bolting with wire mesh are used and studied. The effects of spacing, distance between rows and diameter of bolts on the support are studied by othorgonal testing method. The influence degree of every key factor on the support is suggested by range analysis. The support measures are refined by fuzzy theory and gray relative analysis method. The effect of support is verified by numerical analysis.The Numerical analysis on the distributions of stress in the wall rocks of the lane with thin coal roof provides logical proofs for the location of the return airway near goaf. The support measures are provided on this basis. The stress, displacement and failure zones in wall rocks of the different lanes are monitored in the field to evaluate the support effect of bolting with wire mesh. The distributions laws of stress, the displacement and the failure zones in wall rocks of lanes with different roofs are found. It is important to control the transformations of the lanes to make sure of the safty of the lanses.There are many new knowledges and research findings from the study on mining technologies of the the fully-mechanized coal mining with sub-level caving in high steep coal seams and support technologies in lanes with thin roofs. These findings will play a key role in practice and theory.