PURPOSE: A method for tri-axial compression test of unsaturated soils and intermediate soils is provided to keep automatically inputted pressure in advance. CONSTITUTION: A method for tri-axial compression test of unsaturated soils and intermediate soils is as follows. A test piece and water are put in a tri-axial chamber of the tri-axial compression device(S1). The test piece is saturated by applying confining pressure and back pressure to it(S2). The air is injected into the saturated test piece to generate a unsaturation sample(S3). Shear strength of the unsaturation sample is measured(S4).
