Peculiarities of initial stress fields in lode deposits in the permafrost zone

The article presents the main results of the research over the period from 2003 to 2020 into the initial stress–strain behavior of 8 lode deposits located in the permafrost zone: in the area of the Chukotka folded region, on the Patamian Plateau, in the south of the TransBaikal Territory and in the Eastern Sayan Mountains. The initial stresses were measured at different temperatures of the mine fields: in the upper layer of permafrost rocks, in completely thawed rocks underlying the permafrost strata and in the transition zone at the permafrost– thawed rock interface. All measurements were taken by the co-authors over the period from 2003 to 2020 using the procedure developed at the Institute of Mining, Ural Branch of the Russian Academy of Sciences, using semi-circular and segmented borehole slotting. The general patterns of the initial stresses in the permafrost are found. The stresses in frozen rocks are close to the hydrostatic stress distribution; in the transition zone and in thawed rocks, the stresses fit with the gravitational–tectonic stresses. The average values of the lateral earth pressure coefficient are obtained for different temperature conditions: 0.9–1.1 in frozen rocks, 1.2–1.5 in the transition zones and 1.5–1.8 in thawed rocks on the lower mine horizons. The percentage of the cryo-tectonic components in the total structure of the initial stress field is assessed. The influence of perennial permafrost is 100 % of the vertical stresses, and the influence of tectonics is 150 %. The results obtained are proposed to be used as the boundary conditions in engineering calculations and in mathematical modeling of stable mine structures design and operation of lode deposits in the permafrost zone with unexplored natural stresses and strains.

Sosnovskaya E. L., Avdeev A. N. Peculiarities of initial stress fields in lode deposits in the permafrost zone. MIAB. Mining Inf. Anal. Bull. 2021;(5—2):162—173. [In Russ]. DOI: 10.25018/0236_1493_2021_52_0_162.

The study was carried out under State Contract No. 075-00581-19-00, Topic No. 0405-2019-0007.

Sosnovskaya E. L.¹, Cand. Sci. (Geol. Mineral.), Senior Research Worker;
Avdeev A. N.¹, Cand. Sci. (Eng.), Senior Research Worker, e-mail: avdeev0706@mail.ru;
¹ Institute of Mining of the Ural Division of Russian Academy of Sciences, Ekaterinburg, Russia.

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