Resilient and Permanent Characteristics of Reinforced Granular Materials by Repeated Load Triaxial Tests

Drained repeated load triaxial compression tests were conducted to investigate the resilient and permanent stress-strain behavior of two granular materials reinforced by a geogrid. In order to obtain more accurate measurement of recoverable deformation, an on-sample measuring method was utilized. Because devices for measuring the axial and lateral deformation are attached to the specimen, the confining pressure is provided by applying a vacuum within the specimen. The effect of a geogrid in reducing the permanent deformation of soils at various combinations of deviator and confining stress is investigated and discussed. The test results indicate that a geogrid can play a significant role in reduction of deformation of the triaxial specimen, and could, therefore, be expected to reduce deformations in the field. However, the results obtained for resilient deformations show that the geogrid does not have a considerable influence on the resilient modulus of the two types of soil (sand and fine gravel) that were tested.