Assessment of Deformations of Earth‘s Surface at Mine Construction on Sub-Soils☆

Abstract The paper provides technical and technological solutions aimed at construction and support erection for up to 50 m deep underground facilities of a relatively moderate extend up to 100 m in unstable mantle rocks, which are carried out by small splitting according to the combined pattern without any specific methods. Thus, reduction of cost and construction period is achievable, which is of a significant importance for resource saving. The authors describe results of studies focused on development of methods to provide support of underground facilities with mass concrete under conditions of semi-stable rocks and application of the combined pattern. Reduction of the splitting value to 0.3 m results in decrease of plastic deformation area by 1.7 times and maximum displacements of adjacent strata contour with 10–15 kPa adhesion factor by 1.5 times. When an optimum volume of modifying agents are added to the composition, concrete strength is improved by 1.7 times after 12 hour curing and by a factor of 7 after 24 hour curing in comparison with that without any additives. The finite element theory was applied at simulating the stress-strain behavior of the non-supported bottom-hole area of rock solid mass and hardening concrete of the monolithic lining erected after wall advance. In such a manner, distribution of maximum strains in the support has been revealed with due regard to concrete hardening. The authors provide a regression model for calculation of an optimal value for splitting and selection of structure and support parameters. Areas of maximum displacements in the solid mass and their influence on the Earth surface deformation have been determined.