Geotechnical Engineering Research Laboratory

What is GERL?
The Geotechnical Engineering Research Laboratory was established in 1989 to provide state-of-the-art research capabilities to assess the engineering properties of Geotechnical reinforced earth systems. Several research projects have been conducted to evaluate the influencing parameters affecting soil-Geotechnical interaction mechanism.

The Laboratory
The laboratory hosts two large pullout boxes. Each box is 3 feet wide, 5 feet long and 2 feet high. The dimensions of the boxes permit testing representative specimen sizes of various types of metallic and geosynthetic reinforcements.

A reinforced-clay soil specimen is loaded in the pullout box for a project to evaluate the interaction properties of geogrids in clay.


The hydraulic loading system in one of the boxes permits conducting long term pullout and confined extension tests on Geotechnical while the other box is being used for short term pullout tests. Direct shear tests to evaluate shear resistance at the Soil-Geotechnical interface are being conducted in a modified large direct shear box. The box has a shear area of 27 inches by 27 inches and uses the hydraulic loading system of one of the pullout boxes.

The geogrid specimen is placed inside the large direct shear box to measure the interface shear resistance between the geogrid and the sand.

Tests are being conducted on reinforcements in both granular and cohesive soils. Results of the testing programs are incorporated in the design of reinforced soil walls, slopes and embankments.

Full-scale pullout tests were performed in the field on several mechanically stabilized earth walls. In-situ tests allowed developing methods for evaluating the testing parameters used in design through comparison with lab test results under similar testing conditions.

The pullout resistance of the reinforcement in a full-scale wall is being evaluated.





The GERL laboratory also hosts a system of five creep testing devices capable of applying constant hydraulic loads to evaluate the 10,000-hours creep characteristics of the geosynthetic specimens. Creep tests are also being conducted in temperature-controlled testing devices to evaluate the accelerated creep characteristics of Geotechnical. Accelerated tests permit evaluating creep characteristics of Geotechnical in short timed intervals.

The creep testing equipment evaluates the geosynthetic deformations in a 10,000-hour creep test.

Temperature-controlled testing equipment for the development of accelerated creep testing procedures for Geotechnical.




GERL facility is housed in the LTRC research laboratories. In addition to these specialized facilities, LTRC also has standard testing equipment for evaluating the unconfined engineering properties of Geotechnical.