Research On Supporting Technology Of 4102 Transportation Roadway In Wenjiapo Coal Mine

Deformation and failure of roadway is a common phenomenon in underground coal mines.There are widespread problems such as large deformation,floor heave and failure of support in the bin Chang mining area.The transportation roadway in the 4102 face of Wenjia-po Coal Mine is taken as the engineering background.The deformation and failure mechanism of roadway is studied by means of laboratory experiment,field observation and theoretical analysis.(1)Through field sampling,rock mechanics,expansibility and X ray diffraction experiments are carried out in the laboratory.The mechanical parameters of surrounding rock are obtained.The experimental results show that the bottom mudstone of 4102 transportation roadway contains high content of minerals such as montmorillonite,illite and kaolinite.The softening coefficient of the bottom plate is 0.3.Tthe water absorption is strong and the expansibility is large.(2)The deformation and failure characteristics of roadway are analyzed by means of surrounding rock loose circle test and roadway surface displacement observation.The root loose circle is 2100mm,that of the side wall of roadway is 1500mm,which belongs to the large loose ring roadway.During tunneling,the main form of roadway deformation is roof subsidence,with a maximum value of 600mm.After excavation,the floor heave is the main and the maximum value is 1500mm.Affected by mining period,roof subsidence and floor heave almost synchronize.The bottom drum has obvious segmentation according to the length direction of the roadway.(3)Through the analysis,the fundamental cause that makes roadway deformating and Failuring is rock lithology,the direct cause is high stress,and the important cause is fracture water.Especially fractured water reduces the strength of surrounding rock.Through the stress analysis,the deformation and failure mechanism of the roadway is revealed.Roof subsides during tunneling under high stress.The additional force causes the side wall of roaway to break in an inverted triangle.The depth of failure increases continuously,thus causing the floor heave.The three sides of the top,the side and the bottom affect each other,and the deformation is intensified.After excavation,it makes floor heave continuously with water swelling under high stress.The additional force causes the side wall of roadway to be destroyed,causing the roof to become unbalanced again,he three sides of the bottom,the side and the top are deformed to balance and the roadway is destroyed.(4)The original support scheme is optimized.Water-proof measures have been taken on the floor.Roof anchors increased from 3 to 5.These enhance the strength of the floor and roof.The new support scheme has been verified by FLACt3D numerical simulation and field engineering test.The results show that the new support scheme can ensure the normal use of roadways.