It is important to investigate the weathering mechanism which effects various properties of rocks.
In this paper it has been investigated the relationship between the degree of weathering by visual inspection and the physical and mineralogical properties of granite rocks at different depth in Kumamoto prefecture.
We examined 676 test-pieces which were prepared from the boring core and the data were subjected to statistical analysis with the following results.
1) Weathering progresses with the change of firstly elastic properties, next of the physical properties and lastly of the mineralogical properties.
2) The existence of heavily weathered rock at about 30 meter deep suggests that the weathering was effected due to contact with groundwater in joints, insisting that some physical changes such as developing joint systems have preceded chemical weathering in the local weathering process at depth.