A method for improving microbial cemented sandy soil

A technology of microbial glue and sand, applied in the field of geotechnical engineering, can solve problems such as hidden safety hazards and loss of strength

Active Publication Date: 2021-05-04
ZUNYI NORMAL COLLEGE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the mutual exclusion of strength and toughness has always been a challenging issue for geotechnical engineering materials
Although the strength of sand reinforced by microbial cementation can reach a high level, it is largely a typical brittle material, that is, the strength is lost instantly after failure, and there are certain hidden dangers in terms of safety.

Method used

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  • A method for improving microbial cemented sandy soil

Examples

Experimental program
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Effect test

Embodiment 1

[0036] A kind of method of improving microbial cemented sand of the present embodiment comprises the following steps:

[0037] (1) Select the appropriate chemo-heterotrophic Gram-positive bacteria, prepare the corresponding medium to cultivate them, and then test the OD of the bacterial solution 600 Value and activity value, store the bacterial solution in a low temperature environment, and activate it regularly to maintain its activity;

[0038] (2) configure the cementing fluid matched with the selected chemo-heterotrophic Gram-positive bacteria;

[0039] (3) preparing soil by mixing cohesive soil, sand and stone in a weight ratio of 2:3:5;

[0040] (4) In parts by weight, mix 2 to 7 parts of sulfuric acid amide, 3 to 8 parts of triisopropanolamine, 10 to 20 parts of talcum powder, and 3 to 10 parts of carbolic acid, and adjust the pH value of the resulting mixture to make it The pH value is 7-9, and the modifying agent is obtained and set aside;

[0041] (5) Add the prep...

Embodiment 2

[0046] In this embodiment, on the basis of the foregoing embodiments, the microorganisms selected for use are further limited, and the chemoheterotrophic Gram-positive bacteria selected in the step (1) is Bacillus sarcina. The bacterial strain was purchased from the American Type Culture Collection, numbered ATCC11859, and the bacterium was a chemoheterotrophic Gram-positive bacterium. The individuals of Bacillus sarcina are oval, with a length of about 2-3 μm. This bacterium is currently the most commonly used bacterium for MICP in the field of geotechnical engineering, and its activity of secreting urease is relatively strong, which is representative to a certain extent. Other parts of this embodiment are the same as those of the foregoing embodiment, and will not be repeated here.

Embodiment 3

[0048] On the basis of the above-mentioned examples, the present embodiment further defines the medium components for cultivating microorganisms, the medium components configured in the step (1), in parts by weight, are 20 parts of yeast extract , 10 parts of ammonium sulfate, and 16 parts of Trisbase. The specific process of culturing microorganisms is as follows:

[0049] Use a constant temperature shaker incubator to carry out aerobic culture of bacteria at 30°C and 120rpm for 24 hours, and then use a microplate reader to measure the OD of the bacterial solution 600 (per unit OD 600 The value corresponds to about 108 bacteria) and the value is about 1.10. Using a conductivity meter to measure its activity is about 2.79mMureahydrolysed min -1 ·OD -1 . The strains were stored in a refrigerator at 4°C and activated regularly to maintain their activity. Other parts of this embodiment are the same as those of the foregoing embodiment, and will not be repeated here.

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Abstract

The invention discloses a method for improving microbial cemented sand, which comprises the following steps: 1) cultivating bacteria, then testing the OD600 value and activity value of the bacterial liquid, and preserving the bacterial liquid; 2) configuring the cementing liquid; 3) preparing soil; 4) Configure the modifier; 5) Add the modifier to the soil, the weight ratio of the modifier to the soil is 1:1000; 6) Then add the bacteria solution, the weight ratio of the bacteria solution to the soil is 100:1 ; 7) Then add cementing liquid, the weight ratio of cementing liquid to soil is 3:10; 8) Finally add 2.5% allicin aqueous solution by mass fraction, and the weight ratio of allicin aqueous solution to soil is 1:1000. The invention proposes a method for improving microbial cemented sand, which can significantly improve the unconfined compressive strength and residual strength of sandy soil, especially improve the original brittleness of microbial cemented sandy soil, increase the toughness at the time of failure, and improve the engineering structure. Safety and stability have positive effects, and are suitable for widespread promotion and application.

Description

technical field [0001] The invention relates to the technical field of geotechnical engineering, in particular to a method for improving microbial cementation of sandy soil. Background technique [0002] Microbe-induced calcium carbonate deposition (MICP) technology is a new soil improvement and reinforcement technology developed in recent years. This technology is based on the biochemical mineralization process that occurs inside the soil in nature - the urease secreted by microorganisms hydrolyzes urea and combines with calcium ions to generate calcium carbonate, which cements the soil particles, thereby improving the physical and mechanical properties of the soil. Purpose. Due to the advantages of energy saving and emission reduction, eco-environmental protection, economical efficiency, and little soil disturbance, this technology has attracted widespread attention from scholars at home and abroad, and a lot of research has been carried out on the engineering properties ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): E02D3/12C12N1/20C12R1/01
CPCC12N1/20E02D3/12
Inventor 袁余洋
Owner ZUNYI NORMAL COLLEGE
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