A plugging structure and construction method after drainage and preloading of soft soil subgrade

Abstract

The invention relates to a plugging structure after drainage and preloading of soft soil subgrade, which is characterized in that the structure is mainly composed of short piles of loose materials, plastic drainage boards, horizontal drainage cushions, vertical grouting pipes and horizontal grouting pipes The short piles of bulk materials are arranged under the horizontal drainage cushion, and vertical grouting pipes and plastic drainage boards are laid inside; the horizontal drainage cushion is laid under the embankment filling, and horizontal grouting pipes are laid inside; the horizontal grouting pipes and The vertical grouting pipes are connected to each other through the three-way joint; after the subgrade drainage preloading is completed, the vertical grouting pipes are used to grout the short piles of bulk materials and the horizontal drainage cushion respectively through the vertical grouting pipes and the horizontal drainage cushion to form vertical grouting Closed short piles and grouted cushion bearing slabs. The invention can not only improve the performance of the subgrade soil through the drainage and consolidation of the subgrade soil, but also solve the problem of excessive settlement after construction of the road section treated by the drainage and consolidation method, and can also improve the bearing capacity and integrity of the subgrade through grouting. The invention also discloses a construction method of the above structure.

Description

technical field [0001] The invention relates to a plugging structure and construction method after drainage and preloading of a soft soil subgrade, which belongs to the field of foundation engineering and is suitable for foundation treatment projects of newly built road projects or reconstruction and expansion projects with large thickness of soft soil layers and high requirements for foundation settlement control. Background technique [0002] Soft soil is widely distributed in my country, and there are areas with deep soft soil covering in the coastal areas, middle and lower reaches of rivers and near lakes. In the construction of highways, we often encounter the situation of crossing farmland, rivers or soil with high water content and a lot of groundwater, which is the so-called soft soil foundation. Soft soil has the characteristics of high water content, low shear strength and poor overload capacity. If it is not handled or handled properly, it will cause foundation i...

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Problems solved by technology

Although the above-mentioned structure has a drainage function and is conducive to the drainage of water on the surface of the foundation to the side ditch on both sides, it is difficult to solve the problem of later consolidation of the subgrade. When the degree of soil consolidation meets the requirements, the later settlement of the foundation is prone to abnormalities

[0006] To sum up, although there are some methods that can be used to deal with the subsidence of the roadbed during the construction period, this method requires a long construction period, sufficient preloading and drainage consolidation time, and cannot solve the soft soil foundation itself. The post-construction settlement problem caused by the inherent secondary consolidation reasons

The composite pile foundation method is to drive a large number of various types of piles into the soft soil foundation to form a composite pile foundation to reduce the settlement of the foundation. The cost of this method is very high, which is more than ten times or even several times that of the drainage consolidation method. More than ten times, can not be used in large quantities in actual engineering

Especially when the strength of the foundation soil is low, a lot of piles need to be drilled, and the project cost is very expensive

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