METHOD OF PROTECTING SUNKEN BUILDINGS AGAINST GROUND WATER UNDERFLOODING Russian patent published in 2010 - IPC E02D31/02 

FIELD: construction.

SUBSTANCE: method of protecting sunken buildings against ground water underflooding consists in the fact that distribution sand cushion is formed, highly compressed silty-clayed soils are removed from the whole underground part of buildings. When constructing underground parts of erected buildings on natural slopes in silty-clayed soils with high level of ground water, above lower boundary of design compressed mass of ground foundation, there developed is ditch, from the depth of lower boundary of compressed mass corresponding to level of lower edge of distribution sand cushion to day surface, the slopes of which correspond to position of planes of lower side edges of design distribution sand cushion which is formed as filtration one and designed in the outline of diagrams of equal vertical and horizontal stresses corresponding to stress of natural soil in lower part of compressed mass. Height of cushion is taken equal to design depth of compressed soil mass, and width of upper and lower edges of cushion is equal; at that, it exceeds width of foundation base on both sides by the value which is determined by graphical drawing of planes tangential to diagram of equal horizontal stresses at an angle to vertical plane, which is equal to angle of internal friction of cushion material to the crossing with plane of foundation base level. Position of side edges of cushion is determined by the planes being drawn from extreme points of upper and lower edges of cushion, which are tangential to diagrams of equal vertical and horizontal stresses till they cross each other; at that, inclination angle of tangential plane to diagram of equal vertical stresses is taken equal to angle of natural slope of natural soil. Then there formed is lower body of cushion in the volume of ditch slopes and upper body of cushion in the volume of upper side edges of cushion; after that, there performed is backfilling of cavities between upper cushion body and ditch slopes with natural soil as per layer-by-layer technology; then underground part of buildings is erected.

EFFECT: maintaining natural hydrological conditions in order to exclude dangerous ground water underflooding of underground parts of buildings, decreasing the scope of ground works concerning development of ditch, reducing material consumption.

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