Permafrost

Hazard Assessment Criteria for Development of Engineering Geological
Processes during Construction in the Area
with Perennially Frozen Ground
110
V. P. Chernyad'ev
(Production and Research Institute for Engineering Survey in Construction)
Abstract: During development of the territory, disturbances of the state of the geocryological
environment are mainly related to removal of topsoil, draining and swamping of territories,
surface leveling, construction of artificial coatings, and erection of engineering structures. The
character of disturbances and interaction between engineering structures and perennially frozen
ground is responsible for the degree of development and intensification of cryogenic processes.
The criteria for assessing the degree of hazard of such cryogenic processes as thermokarst,
frost heaving, thermal erosion, and earth flow have been determined taking into account the
development of the regions with perennially frozen ground. Based on the quantitative estimates,
we classified the manifestation of these processes as not hazardous, slightly hazardous,
hazardous, and very hazardous.
The degree of hazard of cryogenic heaving is characterized by the total value of heaving.
The risk of development of thermokarst depends on the total thermal settlement. The predicted
earth flow area and slope steepness are taken into account when hazard assessment is performed
for cryogenic earth flow. The hydrothermal potential, which is used to determine the maximal
depth of downward cutting in frozen rock, is accepted as a quantitative indicator of thermal
erosion hazard.
The performed studies of the manifestation of the most hazardous cryogenic processes
made it possible to determine the possible permissibility of technogenic load during the
development of the territory:
Processes Technogenic load
Not hazardous Permissible
Slightly hazardous Permissible after certain protective measures
Hazardous Permissible after the complex of protective measures
Very hazardous Impossible
Key words: Cryogenic processes, degree of hazard, technogenic load.
Rock glaciers and mountain permafrost in Zanskar, NW Indian
Himalaya
W A Mitchell
(Department of Geography, Durham University, South Road, DURHAM DH1 3LE UK)
Abstract: Rock glaciers form an important landform associated with the interaction of
permafrost and the coarse sediment system within high mountains. In Zanskar, rock glaciers
are widely distributed north of latitude 32º N where there is a marked decline in precipitation