According to the function that GDS dynamic hollow cylinder torsional apparatus can apply three-dimengional dynamic loads

namely axial load

torque and one of inner and outer pressure

three possible stress paths those coincided with practical engineering backgroud are presented by exactly mathematical derivation. When the three-dimengional dynamic loads meet some corresponding requirements

the following paths can be realized

①the stress path which the mean principal stress p and shear stress q are kept constant; ②the stress path that the shear stress q is kept constant when the effect of intermediate principal stress b equals to 0.5; ③the stress path that the mean principal stress p is kept constant when the mutation of which is the rotation of maximan principal stress relative to the vertical direction is 90º. In addition

the first two paths provided theoretical foundation for experiment of simulating the stress paths under wave loading while the third path can be used to simulate the dynamic characteristics of soils subjected to earthquake load

and the three above stress paths can’t be realized in the HCA which with two dynamic loads