KR20110087141A - Method for improving soft ground using urease-producing microorganism - Google Patents

Abstract

PURPOSE: An improvement method of flimsy ground is provided to ensure environmental-friendliness and to strengthen the flimsy ground by effectively filling air gaps within the flimsy ground. CONSTITUTION: An improvement method of flimsy ground using urease-producing microorganisms is provided to strengthen the flimsy ground by cultivating the urease-producing microorganisms within the flimsy ground. The flimsy ground on which the microorganisms are cultivated includes urea and calcium components. A method for cultivating the urease-producing microorganisms comprises the steps of: preparing a culture medium; inoculating the urease-producing microorganisms to the culture medium; mixing water with the culture medium including the microorganisms; and injecting the mixed solution into the flimsy ground.

Description

Method for improving soft ground using urease-producing microorganism

The present invention relates to a method for strengthening soft ground using microorganisms producing urease. Specifically, the present invention relates to a method of culturing urease-producing microorganisms in soft ground containing urea and calcium components to strengthen the soft ground through the product.

Soft ground refers to a ground composed of soft soil with low shear strength and high compressibility due to the nature of soil. Soft ground of the geotechnical concept refers to ground that needs to be improved in consideration of the size, load, and type of the structure to be built on the target ground. it means. The engineering characteristics of each type of soft soil are as follows.

division characteristic Weathered remnant soil    Rocks are weathered and soiled on the surface and remain in the site, including colluvial soils or surficial soils. Due to the large gap between soil particles and low adhesion, ground disasters such as landslides occur frequently during sudden saturation. Haesung Clay   It is composed of blue gray homogeneous clay and silt. N value of SPT is about 5 or less, which is small in shear strength and high in compressibility. Sand layer   The sand layer is composed of fine sand, and the N value is 10 or less and the uniformity coefficient is small. The grain size of sand is 0.1 ~ 1mm, and when the relative density is less than 35%, liquefaction may occur during vibration and earthquake. Indigenous soil (Peat)   The organic soils of vegetation that make up the soft ground are also called nitan or peat, and the stability and settlement problems are more serious than the soft ground because the shear strength is small and the compressibility is large. If the content of organic soil is more than 5%, there is a high possibility of settlement and bearing problems. In particular, organic soils need to be noted because secondary consolidation characteristics are large.

The engineering problems that occur in the soft ground are settlement problems caused by the compressibility of the soil such as consolidation settlement and sub-frictional forces acting on the pile, and the shear resistance of the soil such as arc activity, supporting force of the foundation and earth pressure when the soil is softly ground. There are stability problems, liquefaction problems caused by dynamic loads such as vibration, and permeability problems such as degree, spraying, and piping.

The classification and application ground of the soft ground improvement method are as follows.

division Improvement principle Main construction method Improvement purpose Applicable ground Load control Lightweight Lightweight materials Ground Support
Ground Shear Suppression
Ground subsidence
Activity destruction prevention
Ensuring Machine's Running Performance Clay soil
Organic soil Load balance Pressurized Earthwork Load distribution Needle method Sheet net method Sand mat method Surface mixing treatment method Clay soil Ground improvement substitution Excavation Replacement Method Prevent destruction of activity, reduce settlement,
Inhibition of ground shear deformation Clay soil
Organic soil Forced Substitution Method dehydration Preloading Consolidation settlement
Promotion of ground strength increase
Activity destruction prevention Clay soil
Organic soil Vertical drainage method Plastic board drain method Sand drain method Pack drain method Groundwater Level Reduction Method Well point method Sandy soil Deep well method Clay soil Quicklime pile method promise Sand compaction pile method Reduction of settlement
Liquefaction prevention
Activity destruction prevention Clay, sandy soil,
Organic soil Vibroflotation method Sandy soil Vibrotamper method Crushed pile method Clay, sandy soil Dynamic Consolidation Method Sandy soil integrity Lime deep mixing process Reduction of settlement
Activity destruction prevention
Ground shear deformation prevention
Piping prevention Clay soil Cement-based deep mixing process Spray Stirring Method Clay, sandy soil Freezing method Indices Chemical injection method Geotechnical Side Flow Prevention Order Sandy soil Spray injection method Clay, sandy soil Exponential Null Pile Method Sandy soil, organic soil Underground structure Skeletal formation Segmented Earthworks Activity destruction prevention
Side flow prevention Clay, sandy soil,
Organic soil Pile cap pile slab method

Among these soft ground improvement methods, the stable treatment method is classified into surface stabilization treatment and deep stabilization treatment depending on the depth of the treatment target, and surface stabilization treatment is usually performed within a range of about 2 to 3 m from the surface, and deeper depth improvement is achieved. This is called deep stability treatment. That is, when various types of construction equipment must enter the soft ground, but the ground is weak enough that these equipment cannot enter, the surface ground must be improved first, which is called surface improvement. On the other hand, in-depth improvement is a method of increasing the strength of the foundation ground to support the structure built on the soft ground. In general, in the case of ultra-soft cohesive soil, the surface layer stabilization treatment method is widely used because the depth of the entire ground can be improved only when the surface layer portion is first improved to secure the runability of construction equipment.

Types and disadvantages of the surface treatment method are as follows.

Classification Method Summary of method Disadvantages Laying method Sand mat By laying sand on the soft soil surface
Securing equipment running and discharge gap index Uneconomical due to sand depletion Geotextile Geotextiles are laid on the surface of the soft soil
Increased access to manpower and equipment Geotextile after construction
Left on the ground Bamboo Mat Continuous bamboo on the soft layer or
Bundled with grids to secure support Bamboo after construction
Left on the ground Draining and drying PTM Gradually build a trench in the surface
Promote surface drainage and dry layer formation Parallel installation after installation Surface drainage Drainage on the surface
Decrease the ground level Parallel installation after installation Vacuum horizontal drainage Install horizontal drainage on the surface layer
Promotes drainage with vacuum Parallel installation after installation

In the principle of improvement, the grouting method, which is in line with solidification and index, injects materials such as cement, lime, fly ash, or lime / fly ash into the gaps of the landfill to improve the bearing capacity of the ground and prevent settlement. It is a construction method which aims at stability (FIG. 9). Grouting drills the injection hole in GRID pattern and injects grout material into soft ground and buried layer. The injection pipe of high strength steel hollowed out in the soft ground and the buried layer is typed, and the grout slurry is injected at a high pressure through a nozzle installed in the injection pipe and injected into the soft ground and the buried layer.

In general grouting injection equipment, the combination of equipment depends on the method.

A typical grouting procedure is as follows.

① Insert the injection rod to the grout point.

② Slowly lift the injection pipe while injecting grout through each rod.

③ Upon reaching the surface, the slurry pump is turned off and the next step is taken.

The ground injection drug classification is as follows.

Water glass (sodium silicate, Na ₂ ^O. NSiO ₂₎ chemical-based classification is as follows.

The disadvantages of the grouting method are as follows.

It is composed of chemical composition and has the disadvantage of polluting the soil. In addition, the gel of the water-based chemical liquid may cause leaching and cause groundwater contamination, and urethane is deteriorated, and thus it is limited to application as a water repellent in the long term.

Injection materials of non-liquid liquid and chemical liquid systems cannot be re-installed at the pre-installed location when repair and reinforcement are required after construction.

In general, the conventional injection chemicals have a high viscosity and low penetration, and in the case of particulates, there is no filtering effect, resulting in particle loss before condensation. If water is diluted by dilution, it becomes milk without gelation.

The methods listed above are physical and chemical compositions that improve the soil bearing capacity of soft ground, inhibit ground shear deformation, inhibit ground subsidence, prevent destruction of activity, prevent liquefaction, anti-piping, soil soil lateral flow index, order, and machine running We are trying to stabilize the same ground.

The present invention aims to provide an environmentally friendly and easy soft ground reinforcement method using microorganisms unlike the existing ground stabilization or reinforcement methods. More specifically, an object of the present invention is to provide a method for strengthening the soft ground using microorganisms that produce solids or precipitates as reaction products in the soft ground.

In order to achieve the above object, the present invention provides a method for strengthening the soft ground by culturing the urease-producing microorganisms in the soft ground. Preferably, the soft ground on which the microorganism is cultured contains urea and calcium components. Preferably, but not limited to, the urease-producing microorganism is a urease-producing bacterium, for example, the urease-producing bacterium may be Sporosarcina pasteurii .

In one embodiment of the present invention, the method for culturing the urease-producing microorganisms in the soft ground, preparing a medium; Inoculating the urease producing microorganism in the medium; Mixing water with the medium containing the microorganisms; And injecting the mixed solution into the soft ground.

Preferably, the medium includes, but is not limited to, urea and calcium components, and may be, for example, unstable organics such as waste paper, food waste, sludge, animal manure, crops and food process waste. In one embodiment, the medium containing the microorganism may be prepared as a powder that can be stored for a long time through a lyophilization process.

Preferably, but not limited to, the urease-producing microorganism is a urease-producing bacterium, for example, the urease-producing bacterium may be Sporosarcina pasteurii .

There is no restriction on the method of injecting the mixed solution into the soft ground, and a conventional ground injection chemical input method may be used.

The soft ground improvement method according to the present invention is an easy method of effectively filling the voids in the soft ground to strengthen the soft ground. Specifically, the method has an effect of strengthening the soft ground by the solidification effect of combining the medium containing urease-producing microorganisms with water to cause a biochemical reaction between the pore water and the granules, to precipitate the new minerals to bind the granules.

1 is inoculated with urea bacteria sporossarsana pasteurii in solution medium [organic + urea (CO (NH ₂ ) ₂ )] and then [sodium nitrate, calcium chloride] of the calcium component (precipitant) The picture shows that the solution is formed as a result of coagulation.
FIG. 2 is an electron microscope (SEM) photograph of the solidified (precipitated) material of FIG. 1.
Figure 3 is a graph showing the results of the X-diffraction analysis (XRD) test for the solidified (precipitate) of FIG.
4 is an X-diffraction analysis (XRD) peak survey graph of SW.
5 is an X-diffraction (XRD) peak survey graph of SB.
6 is an X-diffraction (XRD) peak survey graph of SBF.
7 is an X-diffraction (XRD) peak survey graph of SBC.
8 is an X-diffraction (XRD) peak survey graph of SBCF.
9 is a schematic diagram showing a grouting method.

Weathering process and action are divided into physical weathering process and chemical weathering process.

Physical weathering refers to the collapse of a material by mechanical forces, such as temperature change, stress relief, freezing of water, or moisture change, and refers to a phenomenon that does not involve chemical changes in the material.

Chemical weathering is a phenomenon in which the minerals in the rock are decomposed and altered to produce a different substance, and it can be said that the chemical displacement of the rock-water-air system is transferred to a more stable state. The chemical action of the soil-forming process is caused by a combination of dissolution, oxidation, hydrolysis, hydration, and carbonation. Among these, the meanings of hydrolysis and carbonic acid bonds are as follows.

Hydrolysis is a chemical reaction that occurs when water and minerals in a rock come into contact. That is, a reaction occurs between H ⁺ or OH ⁻ ions of water and ions in the mineral. In particular, if there is a supply of H ⁺ ions for OH ⁻ ions which tend to increase during hydrolysis, hydrolysis continues.

Carbonate bond refers to the reaction of minerals with carbonate or bicarbonate ions. Carbonates are usually produced in the intermediate stages of weathering. The carbonate is converted back to other substances and is not the end product of the weathering. Chemical weathering, in which organisms are involved, is also called chelation. Corrosive acts as an accelerator of weathering.

-Attribute Course

Unresolved sediment deposited under the sea or lake is a general term for various changes or actions that occur in a series of processes until it becomes more gradual, petrified, and hard sedimentary rocks.The property action is a broad consolidation, freezing, and recrystallization. Physical and chemical changes such as shifts are known.

In addition, the production work produced at low temperature and low pressure (a condition close to atmospheric pressure at room temperature) is a property action, and the production work produced at high temperature and high pressure is called metamorphism. Geologically, however, the categorical and metamorphic processes are in a continuous relationship.

Classification of the attribution process

Depending on the type of sediment and the environment of sedimentation, the changes and actions that occur in a series of processes other than sedimentary rocks are different, but the attribute action is generally considered to be the following process.

① As sediment is deposited from clay or sand under water, the physicochemical and biological action between chemical and organic matter contained in the water is activated and oxidation-reduction reaction occurs. And this redox reaction causes clay minerals to be mutated or produced.

(2) The deposit load on unfinished sediment increases the load, and the sediment decreases in volume (increase in density and water content), rearrangement of granules occurs, and the physical change occurs. .

③ When the sediment gradually decreases in volume due to consolidation, a chemical reaction occurs between the sediment's pore water and the granules, and new minerals precipitate to bind the granules. In addition, as the hydrogen ion concentration and the redox potential of the pore water change, the alternating action such as dissolution of CaCO ₃ to form quartz (SiO ₂ ) also proceeds.

④ As the sediment depth of sediment deepens, the pressure and geothermal heat increases, and the chemical reaction between the pore water and the granules occurs more actively, and the alternating and recrystallization of minerals occurs. As a result, crystals of coarse minerals and solids are dissolved or new minerals are formed, and crystals grow largely, resulting in hard sedimentary rocks. In addition, if acupressure or geothermal heat is increased to enter the range of metamorphism.

-Freezing

Mineral action dissolved in water is precipitated in the gaps of the deposits to bind the particles to each other is called cementation.

In addition, the mineral precipitated by this coagulation action is called a cement. The solids are often silica (SiO ₂ ) or calcium carbonate (CaCO ₃ ). Silica and calcium carbonate frequently alternate with each other due to chemical changes in pore water.

Silica (SiO ₂ ) is generated as gel-like lead in organisms such as dispersing layers and diatoms, apart from chemical precipitation due to changes in hydrogen ion concentration (pH).

It is known that this gel-like nitrate is stabilized by Oulu → Calcedoni → Quartz.

Calcium carbonate is produced as lime lead when the amount of carbon dioxide (CO2) decreases, the hydrogen ion concentration changes, and the evaporation of moisture. Carbonate is also produced by biochemical precipitation by organisms such as corals and limestones and analysis of organic matter by bacterial action. It is known that precipitation of carbonates takes place vigorously in places where sea and fresh water are well mixed. The color of the deposits (particularly sand) is governed by the redox state of the iron ions contained in the solids.

Biological weathering refers to the decomposition of rocks by animals or plants. The roots of the trees penetrate into the cracks of the rock and expand, and special bacteria expand and destroy the rock by concentrating organic matter in the rock. However, this action is rather deeply related to soil production. This relationship is a combination of physical and chemical weathering. For example, it is possible to destroy soil particles, to move and mix substances, to change chemical composition, to generate heat, and to change pH.

In order to stabilize the ground by increasing the ground strength or order, the gelation method of water glass is used.

1. Gelation with Acid Reagent

Na ₂ ^O. nSiO ₂ + H ₂ SO ₄ ----> Na ₂ SO ₄ + H ₂ O + nSiO ₂

Na ₂ ^O. nSiO _{2 +} 2H ₃ PO ₄ ----> 3Na ₃ PO ₄ + 3H ₂ O + nSiO ₂

2. Gelation by Metal Salt

Na ₂ ^O. nSiO ₂ + CaCl ₂ + H ₂ 0 ----> 2NaCl + Ca (OH) ₂ + nSiO ₂

3. Gelation with alkali (basic) reagent

a. Na ₂ ^O. nSiO ₂ + 2 NaHCO ₃ ----> 2Na ₂ CO ₃ + H ₂ O + nSiO ₂ ---> SGR

   b. Water glass + cement ----> L.W.

Na ₂ ^O. SiO ₂ + Ca (OH) ₂ ----> 2 NaOH + CaSiO _{3 ( calcium silicate )}

Na ₂ ^O. SiO ₂ + CaSO ₄ ----> Na ₂ SO ₄ + CaSiO _{3 ( calcium silicate )}

4. Gelation by Organic Reagent

Na ₂ ^O. nSiO ₂ + 2CH ₃ COOC ₂ H ₅ ----> 2CH ₃ COONa + 2C ₂ H ₅ OH + nSiO ₂

5. Gelation by carbon dioxide gas (gas-liquid reaction)

Na ₂ ^O. nSiO ₂ + CO ₂ ----> 2Na ₂ CO ₃ + nSiO ₂

The final compounds of this gelation are the same as those mentioned in the literature with sodium carbonate, sodium sulfate, sodium chloride, sodium hydroxide, trisodium phosphate, silicic acid (silica, SiO ₂ ) and the like. In addition, it can be seen that silicic acid (silica, SiO ₂ ) and lime (CaO) are the main components of cement as silicic acid (silica, SiO ₂ ) and calcium carbonate (CaCO ₃ ). Based on this, the following equation is established.

              Urease

                ↓

_{CO (NH 2) 2 + 2H} 2 O → CO 3 2 - + 2NH 4 +

                           ↓

Ca ²⁺ + CO ₃ ^2- → CaCO ₃ ↓

It is the principle that urea bacteria are used to produce hydrolase, and the action of carbonate is separated and the separated carbonate reacts in a secondary reaction to produce Vaterite, a kind of calcium carbonate.

Vaterite, which is a solid substance, is dissolved again as the hydrogen ion concentration and the redox potential of the pore water change, and thus, quartz (SiO ₂ ) is formed to alternate. This principle of the present invention could be understood through the following examples.

Hereinafter, the present invention will be described in detail by way of examples. However, the following examples are only for illustrating the present invention, and do not limit the content of the present invention.

In the following examples and the accompanying drawings, soil = S; Water = W; Sporosarcina pasteurii solution medium [organics + urea (CO (NH ₂ ) ₂ )] = B; Calcium nitrate (precipitating agent) [sodium nitrate, calcium chloride] = F; Calcined lime [Ca (OH) ₂ ] = C.

Example  One.

First, Sporosarcina , the element bacterium The pasteurii was inoculated into a solution medium [organic material + urea (CO (NH ₂ ) ₂ )], and then a solution of calcium component (precipitant) [sodium nitrate, calcium chloride] was added. ).

The solidified (precipitated) water was dried and commissioned to Gwangju branch of Korea Institute of Basic Science (EMS) (FIG. 2) and X-diffraction analysis (XRD) test (FIG. 3).

X-diffraction analysis (XRD) confirmed that the reaction product was Vaterite, a kind of calcium carbonate (Table 4).

List of reaction products of X-ray diffraction (XRD) for BF Card no Chemical formula Mineral name 21-0920 Fe ₂ O ₃ Iron oxide 33-0268 CaCO ₃ Vaterite 36-0018 SrSiO ₃ Strontium silicate 36-1148 IrSi ₃ Iridium silicide 40-1041 Cs ₂ K2Cd ₃ O ₅ Cesium Potassium Cadmium Oxide 46-1185 LiHS Lithuim Hydrogen SulFide 36-1442 CuO.3MnO.7Cr ₂ S ₄ Copper Manganese Chromium Sulfide 38-0166 Ba (PO ₃ ) ₂ Barium phosphate 46-0111 K2SO ₄ .7 KHSO ₄ .H ₂ 0 Potassium Hydrogen Sulfate Hydrate

Example  2.

4-8 and Table 6-10 show the results of X-diffraction analysis (XRD) for each sample type after curing. These results showed that urea bacteria produced hydrolases and separated carbonates by action, and the separated carbonates combined with other molecules to freeze and form aterite, a type of calcium carbonate. It is said that quartz (SiO ₂ ) was produced by alternating action of changing and dissolving hydrogen ion concentration and redox potential of pore water.

Types of samples and ground stability related products used in this experiment division Soil stability related products BF Vaterite SW none SB SiO ₂ SBF SiO ₂ SBC SiO ₂ SBFC SiO ₂

List of reaction products of X-ray diffraction (XRD) on SW Card no Chemical formula Mineral name 35-0411 KNd (MoO ₄ ) ₂ Potassium Neodymium Molybdenum Oxide 39-0119 Li ₄ P ₄ O12BH ₂ O Lithium Phosphate Hydroxide 37-0526 Cu ₃ (SO ₄ ) ₂ (OH) ₂ Copper Sulfate Hydroxide 29-0411 CsLiSeO ₄ Cesium Lithium Selenate 40-0842 BaHgS ₂ Barium merury sulfate 33-0345 CsBa (PO ₃ ) 3 H ₂ O Cesium Barium Phosphate Hydrate 31-0542 GaGeO ₅ WO ₅ O ₄ Gallium Germanium Tungsten Oxide 45-0732 CI ₄ H ₂ I Ce ₂ CsOI ₄ Cesium Cerium Acetate 46-0275 Cs ₂ Mn (PO ₃ ) ₄ Cesium Manganese Phosphate

List of reaction products of X-ray diffraction (XRD) on SB Card no Chemical formula Mineral name 43-0596 SiO ₂ Silicon oxide 35-0395 CsRbWO ₄ Cesium Rubidium Tungsten Oxide 13-0487 EuBO ₃ Europium Borate 46-1045 SiO ₂ Quartz syn 39-0119 Li ₄ P ₄ O12BH ₂ O Lithium Phosphate Hydroxide 37-0526 Cu 3 (SO ₄ ) 2 (OH) ₂ Copper Sulfate Hydroxide 33-1286 Na ₂ S ₂ O ₄ Sodium Sulfate 43-0548 K3AlB8O15 Potassium aluminum borate 36-1149 IrSix Iridium silicide 31-0524 GaGeO ₅ WO5O ₄ Gallium Germanium Tungsten Oxide

List of reaction products of X-ray diffraction (XRD) on SBF Card no Chemical formula Mineral name 37-0652 K3Sc (SO ₄ ) ₃ Potassium Scandium Sulfate 35-0395 CsRbWO ₄ Cesium Rubidium Tungsten Oxide 37-0526 Cu ₃ (SO ₄ ) 2 (OH) ₂ Copper Sulfate Hydroxide 33-1286 Na ₂ S ₂ O ₄ Sodium Sulfate 33-0394 Cr ₂ H ₂ As ₆ O19 Chromium Hydrogen Arsenate 35-0411 KNd (MoO ₄ ) ² Potassium Neodymium Molybdenum Oxide 12-0708 SiO ² Silicon oxide 45-0275 CsMgPO ₄ Cesium Magnesium Phosphate 35-0160 Ba10P6O25 Barium phosphate 37-1240 Gd (ReO ₄ ) ³ Gadolinium Rhenium Oxide

 List of reaction products of X-ray diffraction (XRD) on SBC Card no Chemical formula Mineral name 41-1487 C Graphite-2h 43-0596 SiO ₂ Silicon oxide 36-1149 IrSix Iridium silicide 33-1286 Na ₂ S ₂ O ₄ Sodium Sulfate 37-1430 Ga1.56CdO.66Te ₃ Cadmium Gallium Telluride 45-1297 Cu1.50ZnO.30Te Copper Zinc Telluride 34-0580 LiBH ₄ Lithium Boron Hydride 10-0423 AlPO ₄ Berlinite, syn 37-0526 Cu ₃ (SO ₄ ) 2 (OH) ₂ Copper Sulfate Hydroxide 45-0275 CsMgPO ₄ Cesium Magnesium Phosphate

List of reaction products of X-ray diffraction (XRD) on SBCF Card no Chemical formula Mineral name 43-0596 SiO ₂ Silicon oxide 35-0395 CsRbWO ₄ Cesium Rubidium Tungsten Oxide 36-1149 IrSix Iridium silicide 31-0524 GaGeO ₅ WO ₅ O ₄ Gallium Germanium Tungsten Oxide 33-1286 Na ₂ S ₂ O ₄ Sodium Sulfate 33-0394 Cr ₂ H ₂ As ₆ O ₁₉ Chromium Hydrogen Arsenate 35-0411 KNd (MoO ₄ ) ₂ Potassium Neodymium Molybdenum Oxide 43-0548 K ₃ AlB ₈ O ₁₅ Potassium aluminum borate 37-0526 Cu ₃ (SO ₄ ) 2 (OH) ₂ Copper Sulfate Hydroxide 36-0207 LiSc (MoO ₄ ) ₂ Lithium Scandium Molybdenum Oxide

Vaterite, a type of calcium carbonate, is a metastable state that is easily transitioned to other crystals, but it is difficult to synthesize. It is expected that, especially, the vaterite has a spherical shape, so that the dispersibility is very good and the reactivity is higher than that of aragonite and calcite, so it is excellent in reactivity with other substrates when used as a filler.

The above embodiment is not made of artificial (Vaterite) through an artificial device, but made in nature using urea bacteria, which can be said to be an environmentally friendly biomaterial that can be used in applicable soft ground improvement methods and equipment.

Claims (8)

Method of strengthening soft ground by culturing urease-producing microorganisms in soft ground. The method of claim 1, wherein the soft ground on which the microorganism is cultured comprises a urea and a calcium component. The method of claim 2, wherein said urease producing microorganism is a urease producing bacterium. The method of claim 3, wherein the urease-producing bacterium is Sporosarcina pasteurii ). According to claim 1, The method of culturing the urease-producing microorganisms in soft ground,
Preparing a medium;
Inoculating the urease producing microorganism in the medium;
Mixing water with the medium containing the microorganisms; And
Injecting the mixed solution into the soft ground. 6. The method of claim 5 wherein said medium comprises urea and a calcium component. 7. The method of claim 6, wherein said urease producing microorganism is a urease producing bacterium. 8. The method of claim 7, wherein the urease producing bacterium is Sporosarcina pasteurii ).

Images