These large triaxial and plane strain devices were constructed in the Rockfill Test Facility of the University of California, Berkeley in the late 1960s to study the effects of particle size on the shear strengths of sands, gravels, and rockfills.
The triaxial specimen is 3 feet in diameter by 7.5 feet high. The chamber, which is being lowered over the test specimen, is designed for cell pressures of 750 psi. Materials with particles as large as 6 inches can be tested in this device.
This plane strain specimen is 2 feet by 4.5 feet in plan dimension, and 4.5 feet high. Materials with particles as large as 4 inches can be tested in this device.