The Geotechnical Laboratory developed rock testing capabilities in the late 1970’s by purchasing a high stress compression machine and creating equipment that would meet the diverse needs required during construction and engineering projects.

Two examples of equipment developed by GZA include a direct shear apparatus designed to test intact soft and friable rock cores whereby samples can be oriented along artificially produced shear and contact planes very easily to determine friction values. The second example is a “strain jacket” designed and built by GZA which allows us to measure both axial and lateral deformations of a rock core simultaneously during shear determining the elastic constants, young’s modulus and Poisson’s ratio.

Some of the analyses the rock testing lab performs are unconfined compression ultimate strength only, unconfined compression with axial and lateral strains determined for elastic constants, triaxially confined compression with or without axial strain measurements, splitting tensile strength, point load determinations and direct shear of natural or created fracture planes. Additionally the laboratory has the capability to prepare rock samples using a diamond wet saw and lapidary device that conform to the ASTM test method D7102, “Test Method for Compressive Strength and Elastic Moduli of Intact Rock Core Specimens Under Varying States of Stress and Temperature.