VERTICAL DRAINAGE METHOD Russian patent published in 2015 - IPC E02B11/00 E02D31/02 E02D17/20 

FIELD: construction.

SUBSTANCE: vertical drainage method consists in the fact that reduction of underground water entering water-saturated soil mass is performed by means of drainage piles. Drainage piles are formed with a system for gravity discharge of drainage water from a landslide slope zone of an elevated territory in wells with diameter of 0.4…0.8 metres. Wells are drilled to the depth of 8…12 metres in water-bearing soil layers with insertion of the wells into the water-nonpermeable soil layer to the depth of 0.2…0.3 metres. Drainage piles are located along upper boundary of landslide plane of sliding with a pitch of 1.5…3 metres, but not closer than three diameters of a drainage pile. By means of a process conductor string there lowered to the well is a tight film-type holder 3.5…5 metres long, with diameter that is by 0.25…0.35 metres bigger than well diameter for temporary reinforcement and compaction of soil of well walls, which is provided with a valve and a pressure gauge for compressed air pressure control. The tight film-type holder is filled with high-pressure compressed air, and then, the process conductor string is removed. Along the location axis of drainage piles there routed by closed driving out of inspection wells is a design drainage sewerage system by cutting-out wells above the water-nonpermeable soil layer using plastic pipes with diameter of 150…250 mm, which have perforation in their tray part. After routing of the design drainage sewerage system is completed, compressed air is relieved from tight film-type holders, and the latter are removed from the wells. A charging pipe is installed in the well for well filling with local coarse soil. The charging pipe consists of a cylindrical part with diameter that is by 0.1…0.15 metres less than well diameter and with length of 3.5…5 metres, and the upper part is cone-shaped and has the height of 0.5…0.6 metres with diameter at the top which is by 0.45…0.55 metres bigger than well diameter. Well head to the depth of 0.3…0.4 metres is filled with local silty-clayed soil by compaction. Therefore, fixation of disperse soils in the landslide slope zone of elevated territories is achieved by protection of its volume against water saturation by migration influx of underground waters by means of gravity vertical drainage of the proposed design, which allows simplifying the construction process technology, reducing labour intensity, material consumption and power consumption for civil works, reducing costs for construction and operation of the facility.

EFFECT: improvement of physical and mechanical properties of disperse soils of landslide slopes, protection against intrusion of underground waters, cooptation and gravity discharge of drainage waters from the landslide prism zone of the elevated territory; simpler technology of construction processes; reduction of labour intensity, material consumption and power consumption for civil works; reduction of costs for construction and operation of the facility.

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