To　simulate　the　continuous　rotation　of　principal　stress　axes,　a　set　of　stress　controlled　bi-directional　cyclic　loading　tests　were　conducted.　Tests　were　performed　with　two　cyclic　stress　components　involving　the　horizontal　shear　stress　(torsional　shear　stress)　and　the　vertical　shear　stress　(stress　difference　between　vertical　normal　stress　and　horizontal　normal　stress)　to　provide　an　approximate　presentation　of　wave　or　seismic　loading　conditions.　The　stress　path　shown　in　the　orthogonal　coordinates　of　stress　difference　and　shear　stress　had　an　elliptical　shape.　The　ratio　of　the　shear　amplitude　between　the　longer　axis　and　shorter　axis　and　the　area　enclosed　by　elliptical　rotational　loading　path　were　controlled　in　a　planned　way.　Test　results　showed　that　the　stress-strain　behavior　was　significantly　affected　by　the　ratio　of　amplitude　of　the　two　shear　stress　components.　But　it　was　nearly　independent　on　the　area　enclosed　by　elliptical　rotational　loading　path.　The　deformation　behaviors　were　classified　as　two　different　types　based　on　the　ratio　value.