Optimization of Smooth Blasting

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The smooth blasting is a controlled blasting widely used in rock tunnel and cavern excavations. In this research project, the fracture process of rock in the smooth blasting has been analyzed and the key factors for improving and optimizing the smooth blasting is made clear.(1) A computer program to simulate the dynamic crack propagation in rock has been developed. Using this code, the rock fracture process in smooth blasting was analyzed and the influence of initiation time accuracy on the fracture process was clarified.(2) Comparing the crack propagation processes in static and dynamic loading, a relation between the dynamic strength and the static one of rock is made clear. Especially, it is pointed out that heterogeneity of micro-scale strength results in the difference of dynamic and static strengths.(3) The Compact Vertical Seismic Prospecting (CVSP) system to inspect the damaged are in the rock around cavern was developed. From the field measurement, it is confirmed that the CVSP system is useful to evaluate the depth of damaged zone around the tunnel.From these results, it is concluded that the high accurate initiation system and CVSP system are useful tool for optimization of the smooth blasting.