Soils and Aggregates Laboratory

The Soils and Aggregates Laboratory is equipped with standard as well as advanced soil testing equipment. The following is a sample of the tests that can be performed in the Soils and Aggregates Laboratory and associated laboratories at Texas A&M University.

• Atterberg limits
• grain size—sieve analysis
• grain size—hydrometer analysis
• laboratory vane shear strength
• consolidation tests (load step)
• hydraulic conductivity test
• triaxial test
• direct shear test
• soil suction test
• cation exchange capacity
• sodium adsorption ratio
• pH
• electrical conductivity
• pressure plate apparatus
• special triaxial test for unsaturated soils
• resonant column test
• cyclic triaxial test
• rod shear test

The following is a sample of the tests that can be performed in the field with the in situ testing equipment in the Geotechnical and Geoenvironmental Program at Texas A&M University.

• drilling rig (Geology Department)
• standard penetration test
• Shelby tube sampling
• cone penetrometer test
• pressuremeter test (TEXAM, OYO, and PENCELL)
• self-boring pressuremeter test (TEXAM)
• borehole shear test
• crosshole test
• load cells (100 tons T/C, 400 tons C, 1000 tons C)
• settlement probe
• WAK test
• LATWAK test
• instrumented hammer test
• geophone recording

Equipment

HM-4000 Erosion Function Apparatus (EFA)

In 1991, Jean-Louis Briaud, program manager of the Geotechnical and Geoenvironmental Program at TTI and professor of civil engineering at Texas A&M University, began work on the design of a new device. He hoped to measure the erodibility of soils and rocks, a phenomenon referred to as scour, which occurs due to the erosion of soil around bridge foundations by the action of flowing water. Shortly thereafter, Briaud was joined by Hamn-Ching Chen, a professor of civil engineering at Texas A&M. The purpose of the research, originally sponsored by the Texas Department of Transportation (TxDOT), was to help prevent bridge failures due to the effects of scour.

Predicting the effects of scour is important because out of the 1,000 bridge failures in the United States over the last 30 years, 60 percent were due to scour. Currently, 25,000 bridges in the U.S. are scour critical, meaning their foundations could fail due to erosion.

After a decade of developmental research by the Scour Research Team at TTI, the HM-4000 Erosion Function Apparatus (EFA) is now being manufactured by the Humboldt Manufacturing Company and patented through TTI and the Texas A&M Technology Licencing Office. The EFA is designed to be used in conjunction with the scour rate in cohesive soils (SRICOS) method of scour prediction, a site specific method (also developed at TTI) that involves collecting soil samples and testing them in the EFA.