応力解放法による地圧測定に関する1, 2の基礎的考察
1970 年 86 巻 983 号 p. 151-156
詳細
1970 年 86 巻 983 号 p. 151-156
Stress relief techniques have been used to determine in situ stresses in rock.
However it is obscure whether the stresses (or strain) are perfectly relieved and become zero stress state or not.
The fundamental problems as mentioned above associated with relief techniques were considered and some results were obtained:
1) The analysis based on the elastic theory for the effectiveness of relief operation was made and the result was obtained that the stresses in rock become zero as the relief operation goes on.
The same result was obtained for the relief by eccentrically overcoring or slit in any shape, and the expression of eq (4) for the relation between radial deformation as the rock is annularly overcored and the stresses in rock in virgin state can be used in these conditions.
2) The expression of eq (11) corresponding to eq (4) in visco-elastic (Burgers) body was obtained.
Using this equation, the _creep in the time required for one measuring work cycle is estimated at very few even in deformable rock.
3) “The residual strain” in liparite in Ashio mine was estimated at negligibly small from the labolatory test.
