Method for soft soil foundation treatment through microorganism grouting sand drain

A technology of soft soil foundation and drainage sand pile, which is applied in the direction of soil protection, chemical instruments and methods, fertilizer mixture, etc. It can solve the problems of sand pile drainage performance decline, uneconomical, large amount of cement slurry, etc., and achieve deformation resistance and bearing capacity, vertical compressive stiffness and strength, pile body stiffness and strength

Inactive Publication Date: 2015-05-20
NANJING FORESTRY UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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.

Method used

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  • Method for soft soil foundation treatment through microorganism grouting sand drain
  • Method for soft soil foundation treatment through microorganism grouting sand drain
  • Method for soft soil foundation treatment through microorganism grouting sand drain

Examples

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Effect test

Embodiment 1

[0034] In this example, a method for treating soft soil foundations with microbial grouting drainage sand piles is used to treat saturated soft clay foundations (such as Figure 4 shown), the method includes the following steps:

[0035] a. In the soft foundation to be treated, use vibration or hammer sinking method to sink into the steel pipe 11 to squeeze the soil to form the pile hole 1, and pre-embed the grouting pipe 6 in the pile hole 1, and the grout outlet is located at the bottom of the pile hole, and Pour sand into the pile hole 1 on the periphery of the grouting pipe 6 and pull out the steel pipe 11 to form a sand pile;

[0036] b. the pre-prepared urease-producing bacteria bacterium liquid 9 (bacterial liquid concentration OD 600 =1.5 diluted 10 times) and nutrient salt solution 10 (solution consists of the calcium chloride of 0.2mol / L, the urea of ​​0.40mol / L, the sodium acetate of 0.15mol / L, the ammonium chloride of 0.01mol / L and the ammonium chloride of 0.1g / L ...

Embodiment 2

[0040] In this example, a method for treating soft soil foundations with microbial grouting drainage sand piles is used to treat saturated soft clay foundations (such as Figure 4 shown), the method includes the following steps:

[0041] a. In the soft foundation to be treated, use vibration or hammer sinking method to sink into the steel pipe 11 to squeeze the soil to form the pile hole 1, and pre-embed the grouting pipe 6 in the pile hole 1, and the grout outlet is located at the bottom of the pile hole, and Pour sand into the pile hole 1 on the periphery of the grouting pipe 6 and pull out the steel pipe 11 to form a sand pile;

[0042] b. Prepare the urease-producing bacteria bacterium liquid 9 (bacterial liquid concentration OD 600 =1.5) and nutrient salt solution 10 (solution consists of the calcium chloride of 0.25mol / L, the urea of ​​0.50mol / L, the sodium acetate of 0.175mol / L, the ammonium chloride of 0.0125mol / L and the yeast of 0.1g / L paste) at the construction si...

Embodiment 3

[0046] In this example, a method of microbial grouting and drainage sand piles for treating soft soil foundations is used to treat saturated silt foundations (such as Figure 5 shown), the method includes the following steps:

[0047] a. In the soft foundation to be treated, use vibration or hammer sinking method to sink into the steel pipe 11 to squeeze the soil to form the pile hole 1, pour coarse sand into the pile hole 1 and pull out the steel pipe 11 to form a sand pile, and the top surface of the pile is slightly 40cm lower than the soil surface around the pile, forming a pile top pit 12;

[0048] b. the pre-prepared urease-producing bacteria bacterium liquid 9 (bacterial liquid concentration OD 600 =1.5) and nutrient salt solution 10 (the solution consists of the calcium chloride of 0.3mol / L, the urea of ​​0.60mol / L, the sodium acetate of 0.2mol / L, the ammonium chloride of 0.015mol / L and the yeast of 0.1g / L paste) according to the volume ratio of 0.06:1, the mixed gro...

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Abstract

Disclosed is a method for soft soil foundation treatment through microorganism grouting sand drain. The method comprises the steps that a, a pile hole 1 is formed in a soft soil foundation to be treated, and sand is poured into the pile hole 1 to form a sand pile; b, a urease-producing microorganism solution 9 and a nutritive salt solution 10 are sequentially and evenly injected into the sand pile through a grouting tube 6, sand cementation is achieved through the microorganism induction calcium carbonate crystal technology, the concentration of the urease-producing microorganism solution 9 and the concentration of the nutritive salt solution 10 are controlled, sand in the pile body forms a specific cementation mode, and the good water permeable characteristic is ensured; c, after the microorganism grouting solidification sand pile is formed, a flexible water permeable sand cushion 4 is laid on the top of the foundation jointly formed by the sand oil and pile space soil 2, prepressing loads 5 are exerted on the top of the flexible water permeable sand cushion 4, pore water in the pile space soil 2 is made to be drained along a drainage channel formed by the sand pile and the sand cushion, the pile space soil is solidified, and the composite foundation with the high bearing capacity is formed jointly through the soft soil obtained after drainage and solidification are carried out on the microorganism grouting sand pile and the flexible water permeable sand cushion covering the soft soil.

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...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E02D3/12E02D3/10C09K17/40
CPCC09K17/40E02D3/10E02D3/12
Inventor 邵光辉黄容聘王海波方炎明赵志峰尤婷
Owner NANJING FORESTRY UNIV
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