Abstract
Micro-crack system in granitic rock was observed by means of scanning electron microscope, liquid penetrant test, soft X-ray photograph and polarized microscope with the following results;
(1) The liquid penetrant test is useful to observe the micro-crack system.
(2) The surface of micro-crack has generally irregular form probably due to the secondary mineral growth or corrision by the infiltration of ground water.
The evaluated results of the micro-crack system by statistical methods are as follows;
(1) The width distribution of micro-crack can be represented by N (t) Δt= K. t-mΔt, where, K, m are the constants, t is the width and N (t) Δt is the number of micro-cracks in the distance between t and t+ Δt
(2) The m-value in the above equation tends to decrease with the increase of rock porosity.
(3) Only slight variations of the area of crack surface in a unit volume and the length of crack in a unit area are recognized in granitic rocks on the porosity of which ranges from 0.76% to 2.79%.
