Study on support technology of concrete- filled steel tubular in roadway with huge thick and rich water soft rock

in order to solve the support problem of extremely sof fock roadiways in shaft bottom of Chagannaoer No. 1 Coal Mine,combined with the physical andmechanical properies of th surounding rock and the damage situation of the roadway in the orial support conitions,the paperused modfied Fenner fomula to estinate the value of the surrounding rock pressure of 0.9 MPa.the reaction force proided by orinal supportwas 0.718 MPain the iseal s te., The requremen of the oaiway stability was that the support reaction force provided by support structure was igget than the supor reaction foce needed by steiling the roadway This paper suggested that insuicient reaction force was the main reason of the roabway surounding rock deformation.A composiesuppor scheme which vas made up of cncrete r赵lld see ubular and thck concretes shotcrete layer was proposed to repart the roadway.this scheme could provide 1.48 MfPa supporing reaction foce theoretically. The result showed that after the roadway repaired two years,the maximum rib to rib convergence of the roadwa was 89 mm,maximum roof to floor convergence was 142 mm. There was no cracking phenomenon in shotcrete layer and no obvious defomation of roadway .The composie suppot scheme which based on concrete-filled steel tubular support could control the deformation of roadway effectively.