混凝土双向多点聚能定向劈裂成缝实验研究

Experimental study on directional splitting of concrete under bidirectional multipoint shaped charge

为解决核岛底板爆破开挖中建基面平整度不高和预留岩层超挖较大的技术难题,基于高速聚能射流定向劈裂冲击与断裂理论,设计了一种双向多点聚能岩石劈裂成缝装置,通过制作双孔预制裂纹混凝土试块进行爆破劈裂成缝模拟实验。实验结果表明:两炮孔之间形成了贯穿混凝土的裂纹,并且裂纹沿切槽方向向两炮孔外侧扩展,整条裂纹基本沿两炮孔中心连线方向。实验验证了双向多点聚能岩石劈裂成缝装置可用于岩石控界爆破切割形成光滑平整壁面,且非切槽方向混凝土未造成损伤。这为核电基坑底板控制精细爆破,实现高平整度和微损伤岩石界面提供了一种新的方法。

In order to solve the technical problems of low flatness of foundation plane and large over excavation of reserved rock during blasting excavation of floor of nuclear island.Based on the theory of high speed shaped charge jet directional splitting impact and fracture,a bidirectional multi-point shaped charge rock splitting device was designed.The simulation experiment of blasting splitting was carried out by making precast concrete blocks with double holes.The experimental results show that a crack through the concrete is formed between the two holes,and the crack expands to the outside of the two holes along the grooves,and the whole crack basically along the Central Line direction of the two holes.The experiment verifies that the bidirectional multi-point shaped rock splitting device can be used for rock boundary blasting to form smooth and flat wall surface,and the concrete in non-grooving direction is not damaged.It provides a new method for controlling fine blasting of nuclear foundation pit floor and realizing high flatness and slightly damaged rock interface.