Closed-System Freezing of Soils in Linings and Earth Embankment Dams

摘要

A brief review of studies of closed-system freezing (no source of water except that in voids) of compacted soils performed by other investigators, and the laboratory and field data collected from Water and Power Resources Service experiences are presented. For compacted soil canal linings, laboratory and field test results show that under certain soil and temperature conditions, freezing decreases soil density near the surface, but increases density at depth. In two linings, the average density increased slightly during a 20-year period. Frost penetration measurements made during the 1978-79 winter on a 1.5-m-thick reservoir lining, on three earth dams under construction, and on the Teton Dam remnant are shown along with associated soil conditions, air freezing indexes, and insulating effects of snow and, for one dam, a loose soil cover. There is a discussion of (1) frost penetration in different types of soil with and without gravel particles, (2) the effect of freezing on soil near the surface of partially completed earth dams during winter shutdown periods, (3) the need for investigating frost conditions in preparation for resumption of embankment placement in the spring, (4) a suggestion of possible detrimental freezing action at the interface between a rock abutment and an earth embankment, and (5) the possibility of crack formation caused by soil shrinkage during freezing action.