A method for treating soft ground with microbial grouting drainage sand pile

Abstract

A method for treating soft ground with microbial grouting drainage sand piles, the steps comprising: a. making a pile hole 1 on the soft foundation to be treated, and pouring sand into the pile hole 1 to form a sand pile; b. using grouting The tube 6 uniformly injects the urease-producing bacteria liquid 9 and the nutrient salt solution 10 into the sand pile in sequence, and cements the sand grains through the technology of microorganism-induced calcium carbonate crystallization, and controls the concentrations of the urease-producing bacteria liquid 9 and the nutrient salt solution 10 to make the pile The sand in the body forms a specific cementation form to ensure that it has good water permeability; c. After the microbial grouting solidification sand pile is formed, a flexible permeable sand cushion 4 is laid on the top of the foundation composed of the sand pile and the soil between the piles. Apply a preload 5 on the top of the flexible permeable sand cushion 4, so that the pore water in the soil between the piles 2 is discharged along the drainage channel formed by the sand pile and the sand cushion, the soil between the piles is consolidated, and the microbial grouting sand pile, The soft soil after drainage and consolidation and the overlying flexible permeable sand cushion jointly form a composite foundation with high bearing capacity.

Description

technical field [0001] The invention relates to a method for treating soft soil foundations by microbial grouting for improving the working performance of sand piles in soft foundations, and belongs to the technical field of foundation treatment. Background technique [0002] Sand piles are made of bulk material sand, and the pile body and the soil between the piles are jointly carried by the overlying sand cushion to form a composite foundation. When dealing with soft clay foundations, sand piles play a role as both a reinforcement and a drainage body. Therefore, it is widely used in foundation treatment in eastern coastal areas of my country. The sand piles currently used in engineering mainly include bulk sand piles and cement grouting sand piles. [0003] Technical solution of prior art one [0004] The bulk sand piles are constructed by sinking pipe pile method or vibratory flushing method. The tube-immersed pile-forming method is to first form a pile hole by vibratin...

AI Technical Summary

Problems solved by technology

However, because the cement slurry fills the pores between the sand particles and blocks the drainage channel of the sand pile, the drainage performance of the sand pile is greatly reduced or even lost, which cannot meet the drainage requirements of the soft soil foundation.

In addition, the amount of cement slurry used in grouted sand piles is relatively large, which is neither economical nor environmentally friendly

[0010] To sum up, the sand piles currently used in engineering cannot achieve both the improvement of bearing capacity and the maintenance of excellent drainage performance.

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