Air exhaust type drainage device for water-rich foundation pit with low permeability coefficient and construction method

Abstract

The invention discloses an air exhaust type drainage device for a low-permeability-coefficient water-rich foundation pit and a construction method. The air exhaust type drainage device comprises a drill bit and an outer pipe arranged outside an inner pipe in a sleeving mode; a positioning groove is formed in the periphery of the top end of the drill bit and internally provided with a rubber lining; the air exhaust type drainage device further comprises water seepage holes formed in the lower half pipe body of the inner pipe; and a water suction hose is arranged in the inner pipe, the lower end of the water suction hose is coiled in a downwards-sunken arc-shaped groove in the upper end face of the drill bit, and the upper end of the water suction hose penetrates through a hose hole in the side wall of the top of the inner pipe and then is connected with a small water pump. The construction speed is high, drainage is conducted from the peripheral side of the foundation pit through mounting holes, and the influence on the foundation pit is avoided; a negative pressure state is created in the inner pipe in an air suction type drainage mode, the device is suitable for drainage of a soil layer with a low permeability coefficient and is also suitable for foundation pit soil layers under other working conditions, and the universality is high; and meanwhile, the cost is low, a constructor does not need to watch at any time, the construction labor cost is saved, and high economic benefits are achieved.

Description

technical field [0001] The invention relates to the field of supporting devices for foundation pit construction, in particular to an air-pumping drainage device and a construction method for low-permeability-coefficient rich-water foundation pits. Background technique [0002] In recent years, with the continuous development of underground projects such as subways, tunnels, large-scale water conservancy projects, and high-rise building foundations, the construction of deep foundation pits has increasingly become an eye-catching technical difficulty and hot issue in construction engineering. How to control groundwater and reduce its negative impact on deep foundation pit excavation and concrete construction has become an important and difficult construction link in the construction of deep foundation pit underground buildings. [0003] When excavating deep foundation pits in areas with high groundwater levels, since the aquifer is cut off, under the action of pressure differe...

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Problems solved by technology

[0010] The technical problem to be solved in the present invention is: for the soil layer with low permeability coefficient, the conventional tube well dewatering method cannot be used, the construction technology of electroosmotic well point dewatering and jet well point dewatering is cumbersome, and the construction cost is high. When it is deeper, the construction difficulty of the water-stop curtain increases greatly with the increase of depth

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