Tadashi Nishida

True Triaxial Test of Rock Under Stress and Strain Rate Control

The significance of true triaxial tests instead of conventional tests has been enhanced because of the need for generalized constitutive laws for geomaterials. To investigate the behavior of rock masses having restricted conditions for strains, tests of marble under strain rate control as well as stress rate control were performed using a specially designed true triaxial apparatus with rigid platens. As an example of a set of restricted conditions, the condition of the mean principal strain being constant was adopted when the octahedral shear strain was increased. The direction of stress paths obtained under these conditions is discussed, along with the elastic, dilatant, and contractile behavior of marble as clarified by stress controlled tests.

A DEVELOPMENT OF THE BASE FRICTION TECHNIQUE AND ITS APPLICATION TO SUBSIDENCE ENGINEERING

SYNOPSIS The base friction apparatus which is capable of supplying the compressed air on the surface of the model can provide the application of the simularity between in-situ and the model for the behaviour of practical rock structures. This paper describes first, a new base friction apparatus which has the stiff metal plate with uretan rubber in stead of endless belt and has a lateral loading system. and next, the phenomenena of cave-in and surface subsidence in shallow coal mining are studied not only for continuous but also discontinuous model.