结构尺寸与龄期对混凝土爆破振动响应的影响

Effects of Dimensions and Age on Concrete Response to Blasting Vibration

为探索新浇大体积混凝土在爆破振动作用下,混凝土结构尺寸及龄期两大因素对其振动响应的影响,采用数值计算方法,分析了多种工况下的混凝土动态响应,比较了不同结构尺寸混凝土的抗振能力大小。结果表明:相同龄期下板状结构的抗振能力最好,柱状次之,正方体最差;随着结构体积的增大,混凝土的爆破振动允许值明显降低。类比实际工程,计算了上下游爆破时重力坝式结构的混凝土动态响应。结果表明:坝踵处混凝土的安全性最高。最后,结合混凝土结构尺寸与龄期因素,提出了新的安全质点峰值振动速度控制表。

The numerical simulation was used to study the effects of dimensions and age on massive fresh concrete response to blasting vibration. The dynamic response of concrete under multi-working conditions were discussed,and the anti-vibration ability of different geometry size on concrete structure was also compared. The results of the simulation showed that under the same age,the plate-type structure had the best ant-vibration ability,secondly the columnar,and the cube the worst. The allowable value of the concrete decreased significantly with the growth of the structure volume. To analogy practical engineering,blasting in the upstream of gravity dam and downstream were calculated and the highest safety was obtained in dam heel. Finally,a new table of safety velocity was proposed based on the effects of dimensions and age on concrete.