Influence of Plunger Stress on Resilient Modulus of Forest Subgrade Soils Obtained from Cyclic CBR Test

The low load-bearing capacity of subgrade soils is typical for forest roads. For the determination resilient modulus Mr unbound natural as well recycled materials, a laboratory triaxial test with cyclic loading generally preferred. volume roads, including an alternative method CBR test, which uses standard devices repeated loading, being tested and applied in practice. soils, procedure determining based on specimen to constant penetration depth 2.54 mm was verified. This extensive dataset obtained from 11 roads Czech Republic, then statistically evaluated. results showed disproportionately high mean values random variability. Further data analysis revealed that reason seemed be chosen methodology. When using this plunger stress can occur, many types greatly exceed their maximum capacity. As result, determined at unrealistically cases disrupted specimen. necessary solution shortcoming censor i.e., exclude unrealistic stresses exceeding limit values.