METHOD FOR RESTORATION OF UNDERGROUND STRUCTURE Russian patent published in 1998 - IPC

FIELD: underground construction engineering. SUBSTANCE: this relates to restoration of underground structures in unstable water-saturated ground. Such structures (metro tunnels, sewerage mains, etc.) built in unstable ground often settle down heavily which hampers their strength and tightness and in result these expensive objects are filled with water and become unusable. According to method, undertaken is lifting of guarding members of underground structure by creating excess ground pressure under this structure and reducing ground pressure above it. This is effected by injecting sand-water mixture into zone located under structure and retrieving ground from zone located above structure. Water-proofing of guarding members during this operation is achieved by cryogenic liquids. EFFECT: higher efficiency. 1 dwg