岩石–钢纤维混凝土复合层动态压缩性能试验研究

Experimental study on dynamic compressive properties of composite layers of rock and steel fiber reinforced concrete

为研究冲击荷载下岩石–钢纤维混凝土复合层抗压性能,利用分离式霍普金森压杆对岩石、钢纤维混凝土和岩石–钢纤维混凝土复合层试件进行了6种应变率下的动态压缩性能试验,并与各类试件的静态抗压强度进行对比分析。结果表明钢纤维混凝土可以有效增强复合层的静态和动态抗压强度,岩石–钢纤维混凝土复合层的动态抗压强度、耗散能和动态强度增长因子(DIF)均具有显著的应变率效应;在相近应变率下复合层的动态抗压强度和耗散能均随钢纤维掺量增大而增大,当钢纤维掺量为80 kg/m^3时复合层的动态抗压强度和耗散能比无钢纤维时最大增幅分别为30.1%和53.9%;钢纤维掺量不大于60kg/m^3可以有效增大复合层的DIF。复合层试件的损伤特征随应变率增大分为4种类型,即混凝土层出现周边张应变破坏、裂纹贯穿复合层、留芯破坏和整体破碎。岩石–钢纤维混凝土复合层的动态力学性能可以为支护结构在冲击荷载下的作用机制提供研究基础。

In order to study dynamic compressive properties of composite layers of rock and steel fiber reinforced concrete(SFRC)under impact load,dynamic compressive experiments of rock,SFRC and rock-SFRC composite layer were conducted using split Hopkinson pressure bar with six strain rates,and dynamic compressive strengths of specimens were compared with their static compressive strengths.The results show that SFRC enhances the static and dynamic compressive strengths of the composite layer.The dynamic compressive strength,energy absorption and dynamic strength increase factor(DIF)of rock-SFRC composite layers were sensitive to the strain rate.The dynamic compressive strength and dissipated energy of composite layers increase with increasing steel fiber content at a similar strain rate.With steel fiber content of 80 kg/m^3,the dynamic compressive strength and dissipated energy of the composite layers respectively show a maximum increase by 30.1%and 53.9%compared with those without steel fiber.Steel fiber within content of 60 kg/m^3 can effectively enhance DIF.With increasing the strain rate,the damage modes of composite layer specimens are divided into four types Including peripheral tensile strain failure of the concrete layer,crack penetrating the composite layer,core-retaining and overall fragment.The dynamic mechanical properties of rock-SFRC composite layers can provide a basis for the study on the mechanical mechanisms of supporting structure under impact loads.