The effect of physical-chemical and chemical factors on peculiarities of swell and osmotic shrinkage of clay provided to unmembrane’s effect is analyzed. It is demonstrate that the genesis of swell due to water inflow in soil and its outflow is principally different and depends on different correlation of clay pore water concentration (Сп) and solutions filter-passing (Сф). The balance equations for five types of swells are adduced. The experimental researches are allowed to obtain the equation for calculation of solution concentration (boundary of osmotic shrinkage Споу). The exceeding of Споу leads to osmotic shrinkage of clay formation. The conclusion of strength and deformation capacity of clay by swell and shrinkage is gained.
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 study presents influence biotic and abiotic components in underground space on formation and changes of sandy soils conditions and properties under peat, contamination of leaking sewages and some industrial enterprises. The regularities of decreasing of density, water permeability and shear strength of sand due to good disintegrated peat by experimental are analyzed. The organic component of biotic genesis leading to extremely negative effect on permeability and mechanical properties of water saturated sands till to quicksands is shown. The local constructional norms for Saint-Petersburg on the base of getting results should be modernized.
In the paper construction specificity of St. Isaak Cathedral’s underground space and engineering geological profile features are considered. The comparative assessment of condition and properties modification of water-saturated quarternary sandy and clay soils during 55 years are taken up (1954-2009). The dynamic of groundwater contamination due to leakage sewers and its aggressiveness are estimated. The researches of microbes activity in soils which are characterized by quasiheavy values are completed. The structural of complex monitoring to secure of St. Isaak Cathedral long-term stability are proposed.
This paper discusses the geobiological and hydrogeochemical processes in St.-Petersburg underground space and their role in corrosion of escalator constructional materials. The special attention were attracted to the ecological conditions which are connected with organic, inorganic contaminants and microbiota transporting to soils and groundwater from leaking sewer system and also from zones of long existing cemeteries. A detailed study and numerical analyses of escalator tunnel constructional materials were carried out to reveal biological defeat and destruction of concrete and grey iron as a result of microbiota destructive activity.
Engineering-geological and hydro-geological features of rent of St. Petersburg are considered. It is noted that at designing buildings for different purposes, in order to ensure their long-term stability it is necessary to analyze the possibility of their transformation the main components of underground space (rocks, underground water, gas, microbiota, underground structures) under the influence of natural and technogenic factors. Examples of transformation of sand-clay soils under the influence of physical and chemical conditions change and activization of microbial activity in underground space are given. The case of transition of a heavy construction to a pre-emergency condition because of mistakes in engineering research and incorrect assigning of computative parameters is analyzed.
In the paper concept and structural of complex engineering geological and geoenvironmental monitoring of architectural and historical monuments are considered. The specificity of engineering geological and hydrogeological conditions by the example of the Isaac Cathedral, the Kazan Cathedral and the Peter and Paul Cathedral is analyzed. The geoenvironmental condition of architectural and historical monuments underground space is estimated. The factors which influence on monuments deformation due to the high degree of underground space transformation and activity of negative natural and technogenic processes are shown. The system of impact monitoring of the Isaac Cathedral, the Kazan Cathedral and the Peter and Paul Cathedral is proposed.