Step blasting is an important part of open-pit mining, which is accompanied by hazards such as large blasting blocks, flying stone splashing, blasting noises, and blasting dust during the blasting process. In order to reduce the harm caused by blasting, this paper uses impact dynamics and rock dynamics to explain the deformation damage and motion law caused by detonation of the material blocked by the gun hole. By simulating the motion of the blocked material in the gun hole, the motion and failure characteristics of the blocked material in the gun hole are revealed. In this paper, geological polymer is introduced into the field of open-pit mine blasting, and 700 g rock powder, 200 g slag, 40 g NaOH solution (30%), and 140 g water glass with a modulus of 3.2 and 80 g of water are selected to prepare geological polymer-modified plugging materials to change rock powder blockage from bulk to solid, and improve the plugging performance. Finally, a field test was carried out in the open-pit mine explosion area, and a comparative test was carried out through the high-speed photography system; it is demonstrated that the modified blocking material could improve the blockage ability of the gun hole, reduce the large block rate of the upper part of the step, reduce the amount of dust, reduce the amount of flying stone, and improve the production efficiency and safety.

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The process of blasting stress wave propagation and crack propagation is directly affected by the physical properties of the rock mass and internal joints in the rock. In soft and hard rock layers, the blasting process is more complicated since the blasting stress wave needs to penetrate two kinds of rocks with different physical properties and the interface between soft rock and hard rock. In this study, the modal transformation of stress waves at the interface of layered composite rock was analyzed, and the process was reproduced by finite element analysis. Furthermore, the development law of cracks was explored. The research results demonstrated that in the single blasting-hole model, a triangular crack area caused by reflected stress waves appeared at the rock interface of rock medium I near the blast hole. In rock medium II, the tensile crack generated by the interface wave appeared on the side away from the blast hole. Besides, the development of the tensile crack was associated with the incident mode of the blast stress wave and the incident angle. In the deep hole blasting model, the incidence of the detonation wave front from hard rock to soft rock promoted the fragmentation of the hard rock.

The process of blasting stress wave propagation and crack propagation is directly affected by the physical properties of the rock mass and internal joints in the rock. In soft and hard rock layers, the blasting process is more complicated due to the blasting stress wave needs to penetrate two kinds of rocks with different physical properties and the interface between soft and hard rock. This study analyzed the modal transformation of stress waves at the interface of composite stratified rock and the process was reproduced by finite element analysis. Further, development law of cracks was also been studied. The research results show that: In the single blasting-hole model, a triangular crack area caused by reflected stress waves appears at the rock interface of rock medium I near the blast hole. In the rock medium II, the tensile crack generated by the interface wave appeared on the side away from the blast hole. And the development of the tensile crack is related to the incident mode of the blast stress wave and the incident angle. In the deep hole blasting model, the incidence of the detonation wave front from hard rock to soft rock promote to the fragmentation of the hard rock.