Prospects for the use of engineering geophysical methods at the hydraulic structure of the Irelyakh river (Western Yakutia)

The construction of hydraulic structures in the permafrost zone leads to the formation of local sources of hydrogenic thawing. The process of formation and expansion of subchannel natural-technogenic talics requires permanent study and monitoring, including the use of new and adaptation of existing methods of engineering geophysical research. The paper examines the results of engineering geophysical surveys aimed at studying the actual engineering, technical and cryohydrogeological state of the drinking water reservoir on the Irelyakh River. The scope of the work included following methods: electrical profiling, natural potential, vertical electrical sounding, dipole sounding, and thermometry. Based on the results of the study, it was determined that the natural-technogenic talic in the terrigenous-carbonate rocks at the base of the reservoir currently continues to develop. Continuous development in the infiltration zone, as well as at the discharge front and observed flow rates has been observed. The thickness of the thawed rocks in the upper reaches of the river, according to the results of geophysical data, does not exceed 20 m, and in the lower reaches of the dam is already at least 100 m. The dynamic nature of the development of the object under study requires continuous engineering and geophysical monitoring to be carried out on a regular basis.