Method for solidifying island reef calcareous sand through indigenous microorganisms

A microbial and calcareous technology, applied in soil protection, construction, infrastructure engineering, etc., can solve the problems of high preparation and preservation costs of exogenous microorganisms, difficult to ignore marine ecological impact, limited freshwater resources on islands and reefs, etc. Proliferation of native urease microorganisms, avoidance of adverse effects, reduced permeability

Active Publication Date: 2019-12-13
CHINA UNIV OF GEOSCIENCES (WUHAN)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although this method is simple and efficient, the long-term impact on marine ecology is difficult to ignore
Laying vegetation can also achieve the effect of fixing calcareous sand, but considering the high salt content of calcareous sand, poor water retention, limited freshwater resources on islands and reefs, and frequent occurrence of bad weather, it is difficult to build vegetation, which easily lea

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  • Method for solidifying island reef calcareous sand through indigenous microorganisms
  • Method for solidifying island reef calcareous sand through indigenous microorganisms
  • Method for solidifying island reef calcareous sand through indigenous microorganisms

Examples

Experimental program
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Effect test

Embodiment 1

[0025] In this case, a method for solidifying calcareous sand on island reefs using native microorganisms, the method includes the following steps:

[0026] (1) Calcareous sand samples were aseptically collected at a depth of 0.5m from a certain island in the South China Sea, and the calculated porosity was 0.45; at the same time, a small amount of calcareous sand samples were dried, and X-ray diffraction tests were performed on the dried calcareous sand.

[0027] (2) preparation of growth-promoting liquid and cementing liquid, the formula of the growth-promoting liquid adopted in the present embodiment is: urea 0.5mol / L, sodium acetate 0.035mol / L, ammonium chloride 0.0125mol / L, yeast extract 0.3g / L L; The formula of cementing fluid used in this example is: 0.5 mol / L urea, 0.035 mol / L sodium acetate, 0.0125 mol / L ammonium chloride, 0.3 g / L yeast extract, and 0.40 mol / L calcium chloride.

[0028] (3) Fill a plexiglass tube with a length of 10 cm and an inner diameter of 5 cm wi...

Embodiment 2

[0036] The steps in this embodiment are basically the same as those in Example 1, except that the formulas of the growth-promoting liquid and the cementing liquid are different in step (2), and the formula of the growth-promoting liquid in this embodiment is: urea 0.3mol / L, sodium acetate 0.045mol / L, ammonium chloride 0.01mol / L, yeast extract 0.1g / L; the cementing liquid formula used in this example is: urea 0.3mol / L, sodium acetate 0.045mol / L, ammonium chloride 0.01mol / L, yeast extract 0.1g / L, calcium chloride 0.25mol / L.

[0037] The value of the unconfined compressive strength of the cured body measured in this embodiment is 1.10 Mpa.

Embodiment 3

[0039]The steps in this embodiment are basically the same as those in Example 1, except that the formulas of the growth-promoting liquid and the cementing liquid are different in step (2), and the formula of the growth-promoting liquid in this embodiment is: urea 0.4mol / L, sodium acetate 0.04mol / L, ammonium chloride 0.011mol / L, yeast extract 0.2g / L; the cementing fluid formula used in this example is: urea 0.4mol / L, sodium acetate 0.04mol / L, ammonium chloride 0.011mol / L, yeast extract 0.2g / L, calcium chloride 0.35mol / L.

[0040] The value of the unconfined compressive strength of the cured body measured in this embodiment is 1.21Mpa.

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Abstract

The invention provides a method for solidifying island reef calcareous sand through indigenous microorganisms. The method for solidifying the island reef calcareous sand through the indigenous microorganisms comprises the specific steps: firstly a calcareous sand sample is adopted through a sterile measure, and growth promotion fluid and consolidating fluid are prepared; when the growth promotionfluid with 1.2 times of the pore volume is injected into the calcareous sand till the concentration of carbonate ions in an effluent is equal to or larger than 70% of the concentration of urea in thegrowth promotion fluid, the growth promotion fluid stops being injected; when the consolidating fluid is injected for the first time, a Tris-HCl buffer solution with 1.2 times of the pore volume of sandy soil is injected into the sandy soil firstly, then the consolidating fluid with the equal pore volume is injected into the calcareous sand, the fluid is injected in the direction from bottom to top, the fluid is continuously injected for 7-9 days, and consolidating is completed; and then demolding and drying are conducted, and a consolidated sample is obtained. Operation is easy, the cost is low, the homogeneity of the solidification effect of the calcareous sand can be effectively improved, and meanwhile the adverse impact on the ecological environment due to introduction of exogenous microorganisms is avoided.

Description

technical field [0001] The invention relates to the field of calcareous sandstone soil reinforcement, in particular to a method for using native microorganisms to solidify calcareous sand of islands and reefs. Background technique [0002] The surface of natural and artificial islands and reefs in the South my country Sea is almost entirely covered by calcareous sand, which is calcareous debris formed by the long-term physical fragmentation of porous coral reefs. Different from quartz sand with similar particle size, calcareous sand has poor roundness, many pores and low dry density in appearance. In addition, the calcareous sand has a high degree of looseness and a large effective force-bearing area, which makes it easy to start and carry under the action of waves, currents or wind. Long-term physical transportation will cause the loss of calcareous sand, and even aggravate the coastal erosion of islands and reefs. It is of great significance to study and solve the immobi...

Claims

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Application Information

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IPC IPC(8): E02D3/12
CPCE02D3/12
Inventor 张家铭周杨朱纪康王殿龙
Owner CHINA UNIV OF GEOSCIENCES (WUHAN)
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