Abstract
An in-situ triaxial test method was invented for accurate evaluation of stress and strain relationships of rock masses in the field. A series of proof tests were conducted at an abandoned quarry of Ohya stone. Comparison was made between the strength characteristics of Ohya stone evaluated by the in-situ triaxial tests conducted in the field and those by laboratory triaxial tests on core samples retrieved by rotary drilling from the same site. The results show that the in-situ triaxial test method on a large specimen is most reasonable and appropriate to evaluate mechanical characteristics of rock masses. The influence of heterogeneity was found significant for small specimens, while the influences of drainage condition and scale effect seem to be rather small.
