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.
Проанализированы инженерно-геологические и геоэкологические условия в основании выдающегося архитектурно-исторического памятника – Казанского собора, расположенного на Казанском острове в Санкт-Петербурге. Проведен историко-экологический анализ особенностей строительства и эксплуатации Казанского собора. Выделены основные загрязнители подземного пространства, оказывающие негативное влияние на состояние и свойства песчано-глинистых грунтов в основании собора, подземные воды и строительные материалы. Выполнен расчет устойчивости Казанского собора, а также проанализированы особенности развития деформаций собора по данным геодезических наблюдений. Показано, что развитие длительных и неравномерных осадок собора вызвано трансформацией грунтов в его основании и разрушением фундамента. Предложены основные принципы мониторинга Казанского собора.
The main natural and anthropogenic factors forming the specificity of environmental conditions in the underground environment, which affects the development of deformations and corrosion processes of transportation tunnels, are considered. Natural factors include radon intake, the presence of buried bogs and marshy rocks. Technogenic factors of underground space pollution are household dumps, sewage system leaks, cemeteries. On the example of some transit tunnels it is shown that engineering-geological and hydrogeological conditions, as well as geo-ecological situation determine the peculiarities of functioning of these structures. It is noted that the destruction of tunnel materials occurs mainly due to the biochemical factor.
Engineering-geological and geo-ecological conditions of the territory of the architectural and historical complex of the Peter and Paul Fortress located on Hare Island have been analyzed. Historical and ecological analysis of the peculiarities of the development of the territory of the fortress, including the construction and operation of the Peter and Paul Cathedral was carried out. The main pollutants of the underground space of the island that have a negative influence on the condition and properties of the sandy-clay soil at the base of the cathedral, underground water and construction materials have been singled out. Calculation of Stability of the Peter and Paul Cathedral was carried out. It is shown that the development of long-term and uneven settlements of the cathedral is caused by the transformation of soils at its base and the destruction of the foundation. The organization of the object monitoring system of the Peter and Paul Cathedral is proposed.
The main leading factors (changes in the stress state of rocks at the base of structures, physico-chemical and biochemical conditions) determining the long-term stability of surface structures are analyzed. It is noted that filtration consolidation is not of practical importance when considering the compressibility of rocks. The influence of physico-chemical factors on sandy-clayey rocks is evident when polluted by runoff with a wide range of mineralization and composition. The effect of intensification of microbial activity, during which biochemical gases are formed and the increase in the content of bacterial mass, on reducing the strength and deformation capacity of clayey rocks is particularly emphasized. It was found that the transformed clay rocks are usually characterized by the presence of quasi-plastic state.