落石连续冲击下废弃混凝土垫层缓冲特性大型现场试验研究

Large scale on-site experimental study on buffering characteristics of abandoned concrete cushion under successive impact of falling rocks

国内建筑垃圾产量逐年递增,处理成本也急剧增加。为了探究废弃混凝土材料在冲击态荷载作用下的动态响应,通过大型现场70 kJ连续落石冲击试验,研究废弃混凝土垫层在连续冲击荷载作用下的缓冲性能。结果表明,采用废弃混凝土垫层后,第1次、第3次和第6次冲击力峰值与无防护情况相比分别减小了76.7%、41.2%和18.2%;垫层缓冲性能存在劣化现象,6次冲击后,冲击力峰值比第1次冲击时增加了3.5倍。随着冲击次数的增加,垫层孔隙率呈降低趋势,且降低趋势逐渐变缓,垫层颗粒平均球度降低,颗粒相对破碎率随装样深度的增加而降低。研究结果可为落石灾害防护提供理论和实践指导。

The production of construction waste has been steadily increasing year by year,accompanied by a sharp rise in processing costs.The production of construction waste in China has been increasing year by year,and the cost of treatment has also sharply increased.In order to explore the dynamic response of abandoned concrete materials under impact loading,a large scale on-site 70 kJ continuous rockfall impact test was conducted to study the buffering performance of abandoned concrete cushion under continuous impact loading.The results showed that after implementing the abandoned concrete cushion,the first,third,and sixth impact peak values decrease by 76.7%,41.2%,and 18.2%respectively,compared to the unprotected condition.After 6 impacts,the peak impact force was 3.5 times higher than that of the first impact.As the number of impacts increased,the porosity of the cushion layer showed a decreasing trend,and the decreasing trend gradually slowed down.The average sphericity of the cushion particles decreased,and the relative particle breakage rate Br decreased with the increase of sample depth.The research results can provide theoretical and practical guidance for rockfall disaster protection.