Stereo-low-level vacuum prepressing soft foundation processing method

Abstract

The present invention discloses a stereo-type low-place vacuum composite precompressed soft foundation treatment method. It is characterized by that said method includes the following steps: firstly, building a layer of horizontal drainage channel between original foundation and soil to be dredger filled; then creating vertical drainage channel in the original foundation; and building secondary layer of horizontal drainage channel on the surface of original foundation according to the height of soil to be dredger filled and making said secondary layer of horizontal drainage channel be communicated with the above-mentioned vertical drainage channel; then laying horizontal pipe in the horizontal drainage channel positioned on the surface of original foundation and making the horizontal pipe be extended to the exterior of cofferdam and performing an interface for connecting with vacuum pump so as to form a stereo-type vacuum drainage system; making dredger fill construction, after the dredger fill construction is completed, making vacuum drainage to simultaneously strengthen upper and lower soft soil foundations and making them be combined into one body.

Description

technical field [0001] The invention relates to a soft soil foundation treatment method in dredging reclamation land reclamation engineering, especially a reasonable and organic combination of various conventional foundation treatment methods such as self-weight consolidation, surcharge preloading, and man-made horizontal and vertical drainage channels. Together, the soft soil foundation treatment method can be processed as soon as the filling is completed without waiting for the self-weight consolidation time, and belongs to the technical field of soft soil foundation treatment in geotechnical engineering. Specifically, it is a three-dimensional low-position vacuum composite preloading soft ground treatment method. Background technique [0002] 1. Soft ground treatment has broad application prospects [0003] With the reduction of available land in cities and the enhancement of people's awareness of environmental protection, in recent years people have increased land recla...

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Problems solved by technology

[0004] 2. Insufficiency of traditional foundation treatment methods

[0005] At present, the conventional treatment methods for dredging soft soil mainly include drainage consolidation method, soil cushion replacement method, rolling and compaction method, replacement and mixing method, etc. These methods have their own scope of application, and drainage consolidation method is applicable For almost most of the soft foundations except peat soil with extremely poor permeability, it mainly includes surcharge preloading method and vacuum preloading method. Preloading enables the settlement of the foundation to be completed ahead of time, and the foundation soil is consolidated to increase the bearing capacity of the foundation. After reaching the requirements, the preload is removed. This method has three disadvantages: first, it requires a large amount of earthwork nearby, and the cost is relatively high; Second, excessive stacking height will cause slope stability problems; third, the construction period is longer

The vacuum preloading method is to lay a sand cushion on the foundation to be treated, and set up a vertical drainage channel (plastic drainage board or sand well), then seal the sand cushion with a film, and use a vacuum pump to clean the sand cushion and the vertical drainage channel. Carry out pumping to reduce the vacuum degree under the film, and at the same time accelerate the foundation consolidation under the action of atmospheric pressure, and stop pumping after reaching the requirements. The disadvantages of this method are: firstly, the bearing capacity of the foundation is limited, generally about 80kPa; The second construction period is longer

The soil replacement method is to dig out the soft soil in the foundation and replace it with high-strength, high-density sand, gravel or lime soil. This method is more suitable for local small amount of soft foundation treatment. Soft foundation treatment is economically unreasonable and wastes construction time

The rolling and compaction method is a method to compact the foundation soil and increase the strength at the same time by using certain mechanical equipment. The advantage of this method is that the construction period is short and the strength is significantly improved, but it is generally only suitable for non-cohesive soil and miscellaneous filling. Soil, unsaturated cohesive soil, etc. It is not suitable for dredger fill soil with high water content and extremely low strength

For the treatment of dredging soft soil, the conventional method must express a certain strength after the dredging is completed and after a period of self-weight consolidation (this process can take as little as 3 to 4 months, and as long as 1 to 2 years). In the future, man-machine material can be used for soft foundation treatment. That is to say, the current conventional method has a long time process of waiting for the self-weight consolidation strength of the dredged fill to increase when dealing with the dredged fill soft soil, which is beneficial at the current time. If this waiting time can be effectively utilized, it will bring immeasurable economic benefits to the project

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