Experimental Research On The Mechanical Properties Of Shotcrete With Steel Fiber Reinforced Concrete

The problems on ground pressure especially appear outstanding and surrounding rock deformed big along with increasing the depth of mining in mines,shotcrete in general drift,after the construction,it is easily appear slit,even it gradually developed to desquamation and lost the latch-up and support action to surrounding rock,as result of leading the drift destroy seriously.The material for deep drift supporting plays an important role in solving the technical difficult problems.Shotcrete with steel fiber reinforced concrete is combined with the excellent characteristics of shotcrete and steel fiber reinforced concrete(SFRC),which is a new kind of compound material and construction method,in order to deeply understand the mechanical performance of shotcrete under different steel fiber volume ration,a further study of it is made to be beneficial to application in the drift support engineering in this paper.According to the mechanical principle of SFRC structure,basic mechanics property test of SFRC under different four steel fiber volume ration(0,0.5%,1.0%,1.5%) is done,when the steel fiber volume ration equal 0.5%,1.0%,1.5%,compared to ordinary concrete,splitting tensile strength improve partly to 22%,40%,66%,flexural strength boost partly to 36%,47%,63%,flexural toughness index I₃₀ improve partly to 2%,12%,78%,when it failures it has characteristics with crack but not break.SFRC semi-circled arch specimen test under different three steel fiber volume ration(0,0.5%,1.0%) is done,we can conclude the results from test,when the steel fiber volume ration reach 0.5%,1.0%,the ultimate bearing capacity improve partly to 50% and 67%,tensile strain of medial ring direction improve partly to 30%and 63% compared with ordinary concrete.The FLAC Finite Element Software numerical simulation is utilized,comparative analysis the failure process,the test results agree well with simulation results.Through numerical simulation of the full drift section, when applied to the same pressure,the SFRC specimen can bear bigger stress and with less top displacement.We have field test under -641m levels bottom hole yard sump in Liudian Colliery of Huaibei Mining(group) Co.,Ltd,when using shotcrete with SFRC, rebounding loss ration of concrete depress 4.94%,as result of reducing the using of concrete.Through field tests and considering the shot-concrete mechanical equipment, it's suitable when using wave section steel fiber volume ration about 0.75%and the length 20mm.Analysis the support principle of shotcrete SFRC and U-steel stent, contrasting the effection between shotcrete and shotcrete SFRC along with U-steel stent,SFRC has high in tension,flexural strength and well in flexural toughness so on character,so that it can effectively barrage crack generating and developing.Shotcrete with SFRC has a litter rebound,so shotcrete stress distribution is more uniform,stress value is small.