EVALUATION OF SOIL-REINFORCEMENT INTERACTION BY LARGE-SCALE PULL-OUT TESTS

Pull-out tests were conducted to evaluate soil-reinforcement interaction for various types of geotextiles and geogrids under varying normal load and soil conditions. All tests were performed using a 4.4 ft x 2.3 ft x 1.5 ft pull-out box and consistent test procedures. Iterative strain measurements were made using wire extensometers mounted along the length of the material to evaluate in-soil strain response and stress transfer. In all, 10 different reinforcement materials were evaluated, including slit-film and coarse woven geotextiles, needle-punched and heat-bonded nonwoven geotextiles, and two types of geogrid. In addition, comparative results were obtained for metal and fiber strip reinforcements. Pull-out resistance was reported as a function of applied normal load. Soil-reinforcement resistance coefficients were found by several methods and are presented as shear stress versus normal stress plots. Load transfer behavior is discussed in terms of observed stress-strain behavior.