MODELS OF FORMATION MECHANISM AND PARAMETERS CALCULATION FOR SURFACE SINKHOLES OVER UNDERGROUND CAVITIES

G. P. Postoev^1,*

¹Sergeev Institute of Environmental Geoscience Russian Academy of Sciences, Ulanskii per. 13, str. 2, Moscow, 101000 Russia

*E-mail: opolzen@geoenv.ru

The stress-strain state (SSS) transformation is considered in the ground mantle layer during the appearance of the contact of its lower side with the underground cavity. The principal stresses distribution are analyzed in the ground massif in accordance with the Mohr-Coulomb theory (taking into account the soil structural strength in the initial state); for the lower part of the soil horizon, just above the cavity; as well as in the dissipative structures of an arch and column shape. The calculation models are investigated that consider SSS in the soil layer above the underground cavity (in the foot of dissipative structures). New equations were obtained that determine the limit state of the cover layer in the local zone above the underground cavity, just before the formation of destructive collapse deformations. The formulas are presented for determining the radius of the failure (collapse), in which the vertical stress at the depth of the cavity top and the structural strength of the cover soils at this depth are the source data. The analysis of the failure preparation mechanism has been performed and the comparison of the calculated values of the failure diameter with the actual data on test examples has been made.

Key words: principal stresses, ground mantle layer, dissipative structures, arch, cylinder, equations, the failure (collapse) radius, mechanism

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