According to the theory of shock waves, the smash district and its forming time, the blasting cavity radius and its expanding characteristics are all discussed in this paper.

Experimental research on the expansion of blast cavity of de-coupling charge in coal;

In this paper, the radius formulae of crushing zone and final chamber in a stemmed and coupling charge springing blasting have been derived according to the springing mechanism, the numerical simulations by LS DYNA 2D software are proved to agree with the results of the theoretical calculations.

Such research findings show that LS-DYNA 2D software can be made available for design and optimization of the parameters of springing blasting.

The numerical simulation using LS DYNA 2D software displays objectively the process of rock fragmentation and chamber evolution in dfferent conditions,which suggests the software is valuable in the design and optimization of springing blast parameters and will play its due role in the spreading and development of the spring technology.

In this paper the Salmon ,s seismic source function (reduced displacement potential) is calculated by using the acceleration measured from the free field in the near region and the seismic source function of the cavity explosion is calculated too according to the explosion model where radial stresses are uniformly applied over the spherical surface and th.