In connection with the study on deep underwater blasting for shaft sinking by well sinking method, the characteristics of the stress waves induced in a hard clay seam and in a concrete material by an explosion of explosives were studied experimentally and discussed in this paper.
The experiments for the study of the stress wave in clayey material were carried out in a hard clay seam located in Hirokawa district in Fukuoka prefecture and those for the study of the stress wave in concrete material were carried out in a large block of concrete.
One of the most important results obtained in this investigation is as follows.
Let's consider the polar coordinate of which origin is the centre of the charge of explosives. Then, at any point in both the hard clay seam and the large block of concrete, the maximum values of the dynamic radial stress, γγ max, and the tangential stresses, θθmax and ΦΦmax, which are induced in these materials by the explosion of explosives, decay with distance from the charge and the relations between these values and the distance, r, and the quantity of explosive, W, can be represented by the following expressions, γ
max=
K (γ/W 1/3) -n, θθ
max=ΦΦmax=
K'(γ/W1/3) -n', where
n and n' are the decay exponents peculiar to the material and
Kand
K'are constants.
抄録全体を表示