喷射纤维混凝土在深井地下空间支护应用关键技术

Research on key technology of hybrid fiber concrete spayed in deep mine roadway

为了解决深井地下空间支护困难,提出了将高韧性改性聚丙烯(粗)纤维与高弹模纤钢纤维混杂掺加到水泥基材料中形成复合水泥基材料,通过喷射工艺在围岩表面形成支护层与锚杆、锚索形成共同支护体的支护方案.试验发现:混杂聚丙烯(粗)纤维水泥基复合材料,适合深井巷道围岩的支护,其中聚丙烯(粗)纤维掺量为体积率0.4%,钢纤维掺量为体积率0.6%;用有限元软件模拟分析法FIAC确定纤维混凝土喷层厚度,可以节约喷层材料;在初喷支护45d后进行纤维混凝土二衬喷射施工,可以避开应力的高峰,使支撑的中心向岩体内部移动.通过矿压显现观测证明纤维混凝土喷层试验段围岩稳定性好于素混凝土试验段.

As the deep mine is difficult to be supported,a construction plan is proposed,in which the high toughness modified polypropylene（thick） fibers and the steel fiber with high elastic modulus are added into the cement-based material to form a kind of composite cement-based material.The composite cement-based material is sprayed on the surrounding rock surface as the supporting layer,working with bolt and cable to form supporting community.Experimental results show that the hybrid fiber concrete is suitable for supporting deep mine with 0.4%,0.6% volume fraction of polypropylene fibers and steel fibers,respectively.Based on finite difference program FIAC,the shotcrete thickness is defined and it can save sprayed materials since it is relatively thin.Besides,it can avoid the peak stress and move support center to rock interior if the secondary lining of the fiber concrete starts after 45d of the first spraying.In addition,the strata behaviors prove that the fiber concrete has better stability than that of the plain concrete.