دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: See permafrost.

n: perennially frozen subsoil.

a type and structure of frozen soil found in a new cold areas of the world. May extend to depths in excess of 1000 meters.

n: the casing that lowers in the perennial freezing zone such as north pole or high cool areas.

n: it made of G degree cement added gypsumn and solt, it uses in low temperature perennial freezing zones.

n: the tendency of permafrost to sink when a heavy weight or structure is placed on it. When the structure is placed on frozen ground, any heat that thaws the soil causes it to become soft, so that the structure sinks or subsides into it.