Well-graded gravels are usually considered non-frost-susceptible, which appears to be a fair
assumption in accordance with universally recognized frost criterions; However, their frost
heave susceptibility is affected by the unavoidable presence of fines (passing through No.
200 sieve, 0.075 mm) and water when used as backfills for high-speed rail (HSR) subgrade.
In practice, non-negligible frost heave would occur within gravels throughout a severe
winter, causing great difficulties for operation and maintenance of high-speed trains which …