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

Abstract

The invention discloses a composite foundation structure of nail-shaped bored piles for reinforcing soft foundations of embankments, which comprises an embankment, a hard shell layer, a soft soil layer and a hard soil layer from top to bottom. The embankment has a number of pile holes, each Each pile hole passes through the hard shell layer from the embankment, and the soft soil layer penetrates to the hard soil layer, and the diameter of the pile hole at a certain depth downward from the lower end of the embankment is larger than the upper and lower diameters. Taking the ground plane as the dividing line, the pile holes above the dividing line are medium-coarse sand, and the pile holes below the dividing line are solidified cement slurry or cement mortar. The invention also discloses a construction method of the nail-shaped bored pile composite foundation structure for reinforcing the soft foundation of the embankment. In the present invention, nail-shaped bored piles are arranged in the soft road foundation with diseases to form a composite foundation with the soil between the piles, thereby enhancing the stability of the roadbed and reducing the settlement of the roadbed.

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 of a nail-shaped bored pile composite foundation structure 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 spli...

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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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