As a multi-purpose underground space, underground chambers have an important role to play in many areas such as mines and railways. In order to investigate the effect of the shape of the chamber on the safety of the refuge under impact loading, dynamic impact tests were carried out on granite slabs with round, square and horseshoe holes, which were observed and analysed with the aid of high-speed photography and digital image correlation(DIC) technology. The research results show that under dynamic impact, the failure mode of the circular hole specimen is shear failure, while the failure mode of the square hole specimen and the horseshoe-shaped hole specimen is tensile-shear mixed failure. As the impact velocity increases, the displacement gradually increases. Along the impact direction, the displacement change along the impact direction is manifested as circular hole > square hole > horseshoe hole. The displacement field on the plate is approximately divided by two boundary lines in an "X" shape, and the displacement gradually decreases from the incident end to the transmission end. Along the vertical direction, the displacement change along the vertical direction is manifested as square hole > horseshoe hole > circular hole, and the displacement at the top of the hole is relatively small. As the impact velocity increases, the peak strain gradually increases, and the peak strain of the shows a trend of square hole > horseshoe hole > circular hole. Along the impact direction, the overall specimen is subjected to a compressive effect, and the strain value first increases and then decreases. Along the vertical direction, it is continuously subjected to a tensile effect, and the strain value continuously increases. Overall, the specimen with a circular hole has the best stability, followed by the horseshoe-shaped hole specimen, and the square hole specimen has the poorest stability.