钙质砂一维冲击响应及吸能特性试验

One-dimensional impact responses and energy absorption of calcareous sand

钙质砂为海相沉积的多孔介质,是防护工程分配层的理想填充材料。利用改进的铝制分离式霍普金森压杆(split Hopkinsonpressurebar,简称SHPB),分别对颗粒级配以及相对密实度相同的南海钙质砂和福建石英砂进行了83组一维冲击试验,得到了应力波透射率、冲击响应和吸能效率曲线,分析了应变率、相对密实度和含水率对两种砂冲击特性的影响。结果表明,相同的荷载和边界条件下,钙质砂的刚度仅为石英砂的1/10。由于内孔隙的存在,钙质砂对冲击波的衰减作用大于石英砂,在承载性能允许的情况下,适当减小相对密实度、增加含水率可有效提高分配层消能效果。

Calcareous sand, as a porous medium deposited in marine environment, is an ideal material used for a protective cushion. A total of 83 SHPB tests were conducted on calcareous sand sampled from South China Sea and silica sands bought from Fujian Province with identical grain size distributions and relative densities. The curves of stress wave transmittance, shock response and energy absorption efficiency were obtained. The effects of strain rate, relative densities and moisture content on the impact characteristics of two kinds of sand were analyzed. It is found that the stiffness of calcareous sand is only 10% that of silica sand under the same load and boundary conditions. Because of the existence of inner pore, the attenuation of shock wave in calcareous sand is greater than that in quartz sand. Within the bearing capacity, reducing relative density and increasing water content can effectively improve energy dissipation effect of protective cushion of calcareous sand.