Testing performed by ATT follows established American Society for Testing Materials (ASTM) recommended procedures, Corp of Engineers (COE) procedures, or United States Bureau of Reclamation (USBR) procedures where ASTM standards are not available. The testing equipment and instrumentation utilized is routinely calibrated, traceable to the National Institute of Standards and Technology (NIST).

In many cases, ATT has enhanced the test equipment with respect to testing sensitivities, automation of recording and other capabilities that may be required for particular projects or client needs. These enhancements are subject to strict design and calibration standards. Cooperative relationships have been established with leading academic institutions which support the performance and application of this equipment (e.g. Colorado School of Mines).

ATT utilizes a Material Testing System Corporation (MTS) closed-loop electro-hydraulic dynamic soil testing system. The equipment is specifically designed to allow for testing of a full range of standard triaxial and cyclic triaxial tests.

The following is a summary of some of the principal features and capabilities of the soils testing laboratory:

• The loading frame is rated at 22,000 pounds.
• The hydraulic actuator is rated at 5,500 pounds with a six inch stroke.
• Load cells have capacities of 5,000, 2,000, 1,000, and 200 pounds.
• Independent control of back pressure allows for performance of constant head or flow pump permeability tests on samples in the 40 triaxial chambers.
• Depending on test complexity, load, pore pressure and deflection data are collected via computerized aquisition systems, or are continuously recorded on an X-Y1-Y2 chart recorder.
• The triaxial chambers are capable of applying confining pressures of up to 500 psi.
• Samples of up to four inches in diameter can be tested.

ATT utilizes two specially designed flow pumps during permeability testing which are capable of accurately testing material with permeabilities in the ranges of 10^-4 to 10^-12 cm/sec.

Our Direct Shear testing capability is also extensive:

• Samples from 2" diameter to 12" x 12" square can be accommodated.
• Tests are performed in double-plane and single-plane direct shear devices.
• Automated recording of results is provided.
• The maximum confining pressure is 6,000 psf for double-plane and 14,000 psf for single-plane shear.
• Tests are performed at field moisture or saturated conditions as required.

Kerry Repola
Manager - Soil Mechanics
krepola@terratesting.com