For given integers a,b,whether there exits such a partition A 1,A 2,A 3 of the set of integers such that any two of n,n+a,n+b are never in the same A i(i=1,2,3) for every n∈Z?This paper gives a necessary and sufficient condition for this partition to exist.

It has been achieved good effects such as well distributed blasting ore lump,reasonable blasting heap,lower earthquake and blast wave through using partition hole small opening short delay blasting technology,adding close coefficients of blast hole and increasing a free surface.