INVESTIGATION ON QUARRY BLAST (II) VIBRATION MEASUREMENT NEAR SHOT POINT

Abstract

The ground motions near shot point are measured at various places, that is, in the quarryand on the ground surface of each different geological structure. The weights of charge are inthe range of 0.1-1 tons and the distances from shot point and measure points are 20--~--120 in.It is confirmed that the displacement, particle velocity and acceleration of the ground motioncaused by explosion are largely related to the blasting conditions, geological structure of themeasure point and the path through which the waves passes. Especially, the tainping of thecharge and the shape of the free surface before the blast are mainly concerned with the emis-sion of elastic waves from the shot point. The size of rock fragments after the blast is foundto be a function of C which is expressed by C=a/W'/'d'. (a: amplitude, W: weight of charge, d: distance between shot point and measure point.)