Construction method of composite foundation structure of dumbbell-shaped bored piles for strengthening embankment soft foundation

Abstract

The invention discloses a dumbbell-shaped bored pile composite foundation structure used for reinforcing soft foundations of an embankment. The structure comprises, from top to bottom, the embankment, a crust layer, a soft soil layer and a hard soil layer, wherein the embankment is provided with a plurality of pile holes, each pile hole passes from the embankment, then through the crust layer and the soft soil layer and finally to the hard soil layer, each pile hole has two major diameter sections, a first major diameter section starts from the lower end of the embankment and extends downwardly to a certain depth, and a second major diameter section is located in the hard soil layer at the bottom end of a pile. With the ground level as a boundary, the part of the pile hole above the boundary is filled with medium coarse sand, and the part of the pile hole below the boundary is filled with solidified cement paste or cement mortar. The invention further discloses a construction method for the dumbbell-shaped bored pile composite foundation structure used for reinforcing soft foundations of the embankment. According to the invention, dumbbell-shaped bored piles are arranged in the soft foundations of a road with diseases and form composite foundations with earth among the piles, so stability of a roadbed is enhanced, and roadbed settlement is reduced.

Description

technical field [0001] The invention relates to a soft foundation treatment technology under an existing road embankment with excessive settlement or cracks, and in particular to a construction method for a composite foundation structure of dumbbell-shaped bored piles for reinforcing the soft foundation of an embankment. Background technique [0002] Due to reasons such as uneven settlement and poor stability of the roadbed, pavement cracking on soft clay foundations is common after opening to traffic. In order to ensure the driving quality, it is necessary to reinforce the soft soil foundation under the existing road embankment. Reinforcement with CFG piles, pipe piles, and mixing piles will cause too much damage to the roadbed and pavement and cannot be used; in order to reduce damage to the roadbed and pavement, grouting, high-pressure rotary grouting piles, etc. are usually used for reinforcement. Engineering practice shows that in soft clay foundations, the existing co...

AI Technical Summary

Problems solved by technology

Engineering practice shows that in soft clay foundations, the existing construction method grouting belongs to splitting grouting, whether it is steel pipe grouting or sleeve valve pipe grouting, it is difficult to form piles, the reinforcement effect is difficult to guarantee, and the soil squeezing effect significantly

During the construction of high-pressure rotary grouting piles, the injection pressure is as high as 25MPa or more, which seriously disturbs the foundation soil, often leads to cracks and displacement, and the large amount of return grout easily pollutes the road surface

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