Triaxial compression test – a test for the compressive strength in all directions of a sample of particulate material, using a triaxial cell.
Tests in which drainage is prevented are called undrained, when pores are allowed to empty tests are called drained. The specimen for triaxial compression test forms a circular cylinder of height-to-diameter ratio between 2 and 2.5 and contains volume of material representative for investigated bedding. The largest particle size shall be smaller than one sixth of the specimen diameter. The specimen stands, with axis vertical, on a pedestal containing porous plate. A stiff impermeable disc forms a loading cap. A flexible impermeable closely fitting membrane of negligible thickness envelopes the specimen and is sealed to the loading cap and to the pedestal. The specimen with loading cap, membrane, and pedestal is immersed in water in a transparent cell. The cell is connected with the pipe to the source of hydraulic confining pres ...