The estimation of main factors which exerts influence upon functioning reliability of system «tunnels – underground space» is executed. It is shown that hydrogeological conditions have a special importance for construction and maintenance of subway tunnels in Saint-Petersburg. The hydrodynamic effect of regional and local water-bearing horizons on development and activation of different processes such as groundwaters flow, quicksands, head water inrush, underground constructions deformation is analyzed. The influence of hydrochemical conditions on formation of underground space aggressiveness to constructional and waterproofing materials of the tunnels is established. The negative effect of underground microbiota activity on degradation of reinforced concrete and castiron tunnel lining is shown.
The natural and technogenic factors effect on exploitation reliability of subway tunnels located in Upper Vendian clays are analyzed. It is noted what the fractured clays has been studied during the exploring of the first metropolitan lines. It is emphasized what the intensity of clay fracturing increases in thalweg zones of paleo-valleys within the bounds of which the quantity of underground water leakages in tunnels increases. The hydrodynamic and hydrochemistry conditions of Vendian high head horizon (lied under clays) influence on deformation and destruction of tunnels lining are investigated. The reduction of clays shear strength parameters under the interaction of clays and liquid phases is experimentally studied. The water extracts chemical composition of disintegrated construction materials and sinter forms are resulted. The important role of biocorroion in constructional and waterproof materials (included bitumen) disintegration is shown. The protection methods of tunnels constructions from biocorrosion are recommended.
In this paper the features of subway construction materials degradation depending on engineering-geological, hydro-geological and geoecological conditions of Saint Petersburg underground space are considered. The basic types of subway construction placing and their destruction specificity depending on influence of water-bearing horizons hydrodynamic and hydro chemical conditions, natural and natural-technogenic gas bio-production and microbial activity are analyzed. The examples of the disintegrated materials and new growths (salt efflorescence, stalactites and others) chemical compound features depending on the content of ground waters basic components affecting on tunnels lining are resulted.