EXPERIENCE OF GPR INVESTIGATION AT ENGINEERING-GEOLOGICAL SURVEY IN CENTRAL YAKUTIA

Abstract

Тhe territory of the Republic of Sakha (Yakutia) is located in the north-eastern part of the Eurasian continent, the Republic is the largest region of the Russian Federation. One of the features of the region is the presence of permafrost. The construction and exploitation of engineering structures is conducted in a harsh climate and difficult engineering-geocryological conditions on this territory. In this case, the disturbance of thermal equilibrium of permafrost, is accompanied by subsidence, deformation of the buildings foundation and structures, and sometimes to their partial destruction. The article presents the results of GPR studies for engineering-geological surveys in Central Yakutia are presented. The relevant research focused on the improvement of assessment of informativeness, efficiency and authenticity of ground condition according to the indications of remote geophysical methods, in particular GPR, is being examined. The results of studies aimed at studying the characteristic features of GPR wave fields for the development of signs of the interpretation of cryogenic processes and phenomena in the soils of the foundations of engineering structures according to GPR data are presented. The wave fields characteristics and GPR signs of talik, water-bearing zones, areas of weakening of the soil, increase the capacity of the active layer caused by the thawing of permafrost, infiltration of the supra permafrost water boundaries identification have been developed and are determined . The selection of interpretative features of permafrost processes at the research site was carried out by comparing the results of GPR with drilling data and analysis of the wave pattern, which considered the configuration, intensity, length of the in-phase axes. The good reproducibility of GPR investigation with the data of electrical resistivity tomography (electrical sounding, multipole sounding) is shown. The effectiveness of GPR in identifying zones, associated with the development of negative cryogenic processes, recommended for drilling for determination of physical and mechanical properties of soils, for example, complicated permafrost conditions of Yakutia.