Vacuum-bag-type liquid injection pressurization combined grouting reinforcement super-soft soil foundation treatment method

Abstract

The invention relates to a vacuum-bag-type liquid injection pressurization combined grouting reinforcement super-soft soil foundation treatment method. Equipment adopted comprises a drainage system and a liquid injection pressurization system. The liquid injection pressurization system comprises liquid injection pressurization bags 10, transverse liquid injection pressurization branch pipes 6, water injection valves 4, tee couplings, a transverse liquid injection pressurization main pipe 13 and liquid injection pressurization equipment 1. The liquid injection pressurization bags 10 are made of elastic materials capable of transmitting liquid pressure. Liquid injection sealing openings 5 are formed in the tops of the corresponding liquid injection pressurization bags 10, and the two sides of the upper portions of the liquid injection pressurization bags 10 communicate with water injection pipes 11 and are further connected to the transverse liquid injection pressurization branch pipes 6 through the water injection pipes 11. The water injection valves 4 are arranged on the transverse liquid injection pressurization branch pipes 6. Vertical drainage plates 9 are distributed on the peripheries of the liquid injection pressurization bags 10. The treatment method includes the following steps of (1) equipment arrangement and communication, (2) a vacuum liquid injection pressurization stage and (3) a grouting pile body forming stage.

Description

technical field [0001] The invention provides a treatment method for soft soil and ultra-soft soil foundation, which belongs to the combined treatment technology of vacuum preloading and composite foundation in geotechnical engineering. Background technique [0002] In recent years, due to the shortage of land resources, land reclamation projects have received more and more attention. As a common foundation treatment method, vacuum preloading method has been widely used in land reclamation projects. The conventional vacuum preloading method is to lay a sand cushion on the surface of the soft soil foundation, set up a plastic drainage board or a sand well, and then use a sealing film to isolate it from the atmosphere. The end of the sealing film is buried with soil. The drainage pipeline of the cushion layer is pumped by vacuum pump or other vacuum means. Under the action of vacuum negative pressure, the negative pressure is gradually formed in the surface sand cushion layer ...

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Problems solved by technology

[0005] 1) For ultra-soft soil foundation, when the vacuum preloading method is used for reinforcement treatment, the drainage volume in the early stage is generally large, and the drainage effect is obvious. In the later stage, the fine-grained silt near the drainage board blocks the drainage board, and the vacuum degree also decreases. , leading to a significant decrease in the drainage rate in the later period, especially the soil far away from the drainage board and the deep layer has not been fully reinforced, which seriously affects the effect of foundation treatment

[0006] 2) Although new vacuum preloading technologies such as electroosmosis combined with vacuum preloading technology have improved the drainage efficiency of vacuum preloading to a certain extent, and thus accelerated the soil consolidation rate, this method has a relatively high engineering cost and cannot be used in actual projects. It is difficult to carry out large-scale promotion and application

[0007] 3) Adopt air pressure splitting vacuum preloading and air injection pressurized vacuum preloading technology to carry out foundation reinforcement treatment. In engineering practice, it is found that air must be blown into the soil continuously through the pressurized pipe to ensure a stable air pressure difference. Once the gas supply is stopped, the vacuum negative pressure decreases, and the drainage rate drops immediately, resulting in poor soil reinforcement effect, especially the reinforcement treatment effect of deep foundation soil is not satisfactory

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