Nail-shaped bored pile compound foundation structure for reinforcing embankment soft foundation, and construction method thereof

Abstract

The invention discloses a nail-shaped bored pile compound foundation structure for reinforcing embankment soft foundation. The nail-shaped bored pile compound foundation structure comprises an embankment, a hard shell layer, a soft clay layer and a hard clay layer from top to bottom, wherein the embankment is provided with a plurality of pile holes; each pile hole penetrates through the hard shell layer, the soft clay layer and the hard clay layer from the embankment; a diameter of each pile hole at a certain depth under the embankment is larger than that of the upper part and the lower part of the pile hole. A ground level is taken as a boundary; the pile holes are equipped with medium coarse sand above the boundary and cured cement paste or cement mortar below the boundary. The invention also discloses a construction method of the nail-shaped bored pile compound foundation structure for reinforcing the embankment soft foundation. By arranging the nail-shaped bored piles in soft embankment of roads with damages and forming the compound foundation with clay among the piles, stability of subgrade is enhanced and subgrade 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 nail-shaped bored pile composite foundation structure and a construction method 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 would cause too much damage to the subgrade and pavement and cannot be used; in order to reduce damage to the subgrade and pavement, grouting and high-pressure rotary grouting piles are usually used for reinforcement. Engineering practice shows that in soft clay foundations, grouting belongs to spl...

AI Technical Summary

Problems solved by technology

Engineering practice shows that in soft clay foundations, grouting belongs to splitting grouting, and whether it is grouting with steel flower tube or sleeve valve tube, it is difficult to form a pile body, the reinforcement effect is difficult to guarantee, and the soil squeezing effect is significant

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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