Resilient modulus and plastic deformation of soil confined in a geocell

Resilient modulus tests were conducted on two coarse-grained soils (gravel and sand) and a fine-grained soil (lean silty clay) in a large-size cell with and without confinement in a geocell. The effect of the geocell on resilient modulus depended on the infill (soil in the geocell). Resilient modulus increased by only 1.4–3.2% when the infill was coarse-grained, but increased by 16.5–17.9% when the infill was fine-grained. The effect on resilient modulus was larger when the fine-grained infill was compacted wet of optimum water content. Larger deformations occurred in the tests on the fine-grained soil, which most likely contributed to the greater increase in resilient modulus when confined in a geocell. Tests with the coarse-grained soils indicated that the rate of long-term strain accumulation in the sand and gravel under constant cyclic loading decreased by approximately 2% when they were confined in geocells.