CN110241809B - Curing agent for reinforcing cohesionless soil by microorganisms and reinforcing method thereof - Google Patents
Curing agent for reinforcing cohesionless soil by microorganisms and reinforcing method thereof Download PDFInfo
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Abstract
The invention discloses a curing agent for reinforcing cohesionless soil by microorganisms and a reinforcing method thereof, wherein the curing agent comprises a solution A, a solution B and a solution C, and the solution A is a mixed solution formed by an anaerobic ammonium oxidation bacteria solution, a urea solution and a calcium nitrite solution; the solution B is a bacillus pasteurii solution; the solution C is a mixed solution of potassium bicarbonate, potassium dihydrogen phosphate, magnesium sulfate, calcium chloride and ferrous sulfate. The curing agent is used for curing the inviscid soil, so that ammonium ions in the inviscid soil can be effectively reduced, nitrogen is generated, the saturation of a soil body is reduced, and the curing effect is improved.
Description
Technical Field
The invention relates to the field of building materials, in particular to a curing agent for reinforcing cohesionless soil by microorganisms and a reinforcing method thereof.
Background
Clay-containing particles of non-cohesive soil are fewer, water permeability is greater, and the clay-containing particles are one of the most common geotechnical media in civil engineering. The inviscid soil has no inherent cohesive force, is easy to damage under the action of load or seepage, and the most common damage case is the liquefaction phenomenon of sand under the action of earthquake. In recent years, it has been proved that sandy soil, silty soil and gravelly soil can be liquefied, and liquefaction prevention becomes the most important part in earthquake-proof and disaster-prevention design. The phenomena of quicksand and hole collapse of cohesionless soil caused by seepage are common operation risks during excavation of a foundation pit tunnel and construction of pile foundation engineering; dam piping is also initiated by the migration of non-cohesive soils by water currents. Therefore, the improvement of the inherent cohesive force of the inviscid soil is the most effective means for preventing engineering accidents related to the inviscid soil.
The existing strengthening method of the cohesionless soil mainly adopts grouting, and comprises various chemical grouting, high polymer grouting, cement grouting and the like. However, due to the viscosity of the slurry, the treatment effect of the grouting material is limited, and some grouting materials can cause pollution to underground water.
In recent years, the microorganism reinforced soil has attracted extensive attention of academia due to its environmental protection and low carbon, and the solution used in the conventional microorganism reinforcement method includes a bacterial solution formed by bacillus pasteurii and a mixed solution made of urea and calcium chloride. The bacteria liquid and the mixed liquid are sequentially added into the soil body to generate calcium carbonate precipitation so as to block the pores of the soil body, and the cemented sand grains achieve the purpose of improving the strength of the soil body.
Although the technology has a wide application range, the technology cannot be popularized and applied on a large scale at present. For example, Van Paassen tries to use the Paecilomyces pasteurianus induced calcium carbonate precipitation in the foundation treatment engineering of a horizontal directional gravel layer, and the detection result shows that a large amount of ammonia root is retained in a reinforced area after the treatment is finished; edward s.kuclfarsbb, 2007, applied for a patent of mixing urea-hydrolyzing bacteria and urea calcium ions in a permeable material to form a cement (US8182604), a ten-year promotion right purchased by the company Deltares in the netherlands, but no commercial project, mainly because ammonia generated after the reaction may pollute groundwater. Many studies have shown that ammonium ions in water are closely related to water eutrophication. The existence of ammonium ions hinders the application of the method, how to reduce or even eliminate the ammonia generated after the reinforcement is finished, and no better treatment method exists in the industry and academia at present.
Disclosure of Invention
In view of the above-mentioned disadvantages of the prior art, the present invention aims to provide a curing agent for strengthening cohesionless soil by microorganisms and a strengthening method thereof, which can effectively reduce ammonium ions in cohesionless soil, generate nitrogen gas, reduce the saturation of soil body and improve the solidification effect.
The technical scheme of the invention is realized as follows:
a curing agent for reinforcing cohesionless soil by microorganisms comprises a solution A, a solution B and a solution C, wherein the solution A is a mixed solution formed by an anaerobic ammonium oxidation bacteria solution, a urea solution and a calcium nitrite solution; the solution B is a bacillus pasteurii solution; the solution C is a mixed solution of potassium bicarbonate, potassium dihydrogen phosphate, magnesium sulfate, calcium chloride and ferrous sulfate.
Furthermore, the molar concentrations of the calcium nitrite solutions in the solution A are equal, and the molar concentration is 10-100 mmol/L.
Further, the OD of the B.pasteurianus solution600Greater than 2.
Further, the concentrations of the components in the solution C are respectively: 2-5 g/L potassium bicarbonate, 40-70 mg/L potassium dihydrogen phosphate, 200-500 mg/L magnesium sulfate, 200-500 mg/L sodium chloride and 8-15 mg/L ferrous sulfate.
Further, the anammox solution is a solution of anammox sludge particles dissolved in water.
A method for reinforcing cohesionless soil specifically comprises the following steps:
(1) surveying to obtain the depth h of the upper surface of the inviscid soil layer to be reinforced from the ground surface and the thickness s of the inviscid soil layer;
(2) preparing a solution A, a solution B and a solution C according to the curing agent for reinforcing the cohesionless soil by the microorganisms for later use;
(3) vertically drilling a plurality of wells downwards on the ground surface of the cohesionless soil layer to be reinforced, wherein all the wells are uniformly distributed in a matrix form at intervals of 1.5-2 m and are divided into grouting wells and pumping wells, the pumping wells are arranged around the grouting wells, and the grouting wells are arranged around the pumping wells; and inserting a steel perforated pipe into each well, wherein the length l of the steel perforated pipe inserted into the ground is
(4) Respectively installing a grouting pipe and a water pumping pipe in the grouting well and the water pumping well in the step (3), wherein one end of the grouting pipe is connected with a steel perforated pipe in the grouting well, and the other end of the grouting pipe is connected with grouting equipment; one end of the water pumping pipe is inserted into the steel perforated pipe in the water pumping well, and the other end of the water pumping pipe is connected with water pumping equipment;
(5) grouting and reinforcing:
5.1) first grouting: after the grouting equipment in the step (4) is communicated with the solution A and the solution C, starting the grouting equipment, injecting the solution A and the solution C into a grouting well according to the volume ratio of 1:9, simultaneously starting a water pumping device, pumping out the solution I in the water pumping well, timely checking the calcium ion concentration in the solution I, stopping pumping water and grouting when the calcium ion concentration in the solution I is more than 60mg/L, and standing for 3 hours;
after the grouting equipment is communicated with the solution B, starting the grouting equipment, injecting the solution B into a grouting well, simultaneously starting a pumping equipment, pumping out the solution II in a pumping well, and simultaneously detecting OD in the solution II600Value as groundwater OD600The value is blank, if the OD of the solution II minus the blank is measured600Stopping pumping water and grouting when the value is more than 0.1, and standing for 24-48 h;
5.2) second grouting: repeating the step 5.1), wherein the volume ratio of the solution A to the solution C in the grouting process is 1: 4;
5.3) third grouting: repeating the step 5.1), wherein the volume ratio of the solution A to the solution C in the grouting process is 1: 1;
5.4) fourth and later grouting: repeating step 5.3);
and after each grouting, detecting the content of calcium carbonate in the inviscid soil layer to be reinforced, and when the content of calcium carbonate in the inviscid soil layer to be reinforced is detected to be more than or equal to a set value, finishing the reinforcement of the inviscid soil layer in the corresponding area of the grouting well.
Further, the vertical error of the drilling construction plane in the step (3) is less than or equal to 80 cm.
Further, when the solution A and the solution C are injected into the grouting well in the step (5), setting the grouting pressure of grouting equipment to be 100-300 KPa; and when the solution B is injected, setting the grouting pressure of grouting equipment to be 10-100 KPa.
Further, the set value of the calcium carbonate content in the step (5) is 10Kg/m3。
Further, the content of calcium carbonate in the cohesionless soil layer in the step (5) is calculated according to the following formula:
wherein: n-the number of repeated slip casting;
a-the molar concentration of urea in solution A, mmol/L;
the content of M-calcium carbonate is Kg/M3。
Compared with the prior art, the invention has the following beneficial effects:
1. according to the invention, the pasteurella bacillus hydrolyzes urea into ammonium ions and carbonate ions, and the ammonium ions and nitrite ions react to generate nitrogen under the action of anaerobic ammonium oxidation bacteria, so that the pollution of the ammonium ions to underground water is effectively avoided, and the generated nitrogen is beneficial to reducing the saturation of sandy soil and improving the liquefaction resistance of soil; and carbonate ions react with calcium ions to generate calcium carbonate, so that the non-adhesive soil is cured, and secondary pollution is avoided.
2. The curing agent adopted by the invention treats the inviscid soil by generating calcium carbonate to glue the inviscid soil and generating nitrogen to reduce the saturation of the inviscid soil, compared with the traditional microorganism reinforcement method, the invention can improve the uniformity of reinforcement, reduce the generation of reinforcement by-product ammonia, reduce the saturation of the inviscid soil layer and contribute to the prevention and treatment of earthquake liquefaction.
Drawings
Fig. 1-schematic view of the cohesive free soil layer reinforced structure of the invention.
Fig. 2-schematic cross-sectional view of reinforcement of cohesionless soil layer according to the present invention.
Wherein: 1-grouting well; 2-pumping well.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
A curing agent for reinforcing cohesionless soil by microorganisms comprises a solution A, a solution B and a solution C, wherein the solution A is a mixed solution formed by an anaerobic ammonium oxidation bacteria solution, a urea solution and a calcium nitrite solution; the solution B is a bacillus pasteurii solution; the solution C is a mixed solution formed by potassium bicarbonate, potassium dihydrogen phosphate, magnesium sulfate, calcium chloride and ferrous sulfate.
The pasteurella is an alkalophilic bacterium rich in soil and can be used in severe environments such as acid, alkali and high salinityCan maintain strong biological activity, and can use urea as energy source to produce a large amount of high-activity urease through metabolic activity to hydrolyze urea to generate NH4 +And CO3 2-In the presence of calcium nitrite, the special cell wall structure of the Pasteurella, the surface of which is provided with a large number of negative ion groups to adsorb Ca2+The Pasteurella pasteuris converts CO by its own vital activities3 2-Transport to cell surface and Ca2+Binding to form calcium carbonate crystals; and NH4 +Under the action of anaerobic ammonium oxidation bacteria, NO in calcium nitrite in anoxic environment2 -Ion to NH4 +The nitrogen is oxidized into nitrogen, the saturation of the soil body is further reduced by the nitrogen, and the reinforcing effect is improved. The reaction formula is as follows:
CO(NH2)2+2H2O→2NH4 ++CO3 2-
Ca2++CO3 2-→CaCO3↓
NH4 ++NO2 -→N2↑+2H2O
the molar concentrations of the urea solution and the calcium nitrite solution in the solution A are equal, and the molar concentration is 10-100 mmol/L. Thus, ammonium ions and carbonate ions generated by urea hydrolysis can respectively and completely react with calcium ions and nitrite ions in calcium nitrite, and the non-cohesive soil can be fully cured, and the ammonium ions can be removed.
OD of the Paenibacillus solution600Greater than 2. The method can ensure that the bacterial liquid contains sufficient pasteurella and can quickly hydrolyze the urea.
The concentration of each component in the solution C is as follows: 2-5 g/L potassium bicarbonate, 40-70 mg/L potassium dihydrogen phosphate, 200-500 mg/L magnesium sulfate, 200-500 mg/L sodium chloride and 8-15 mg/L ferrous sulfate. The solution C provides nutrient solution for the anaerobic ammonium oxidation bacteria to grow.
The anaerobic ammonia oxidation bacteria solution is formed by dissolving anaerobic ammonia oxidation sludge particles in water, and the anaerobic ammonia oxidation sludge particles come from an anaerobic ammonia oxidation process sewage treatment plant or an EGSB reactor. The anaerobic ammonia oxidizing bacteria are aggregated into a granular sludge form and converted into biomass, and the biomass of the added anaerobic ammonia oxidizing bacteria is 100-500 times of that of a bacillus pasteurianus solution with the same volume.
Referring to fig. 1 and 2, a method for reinforcing cohesionless soil specifically includes the following steps:
(1) surveying to obtain the depth h of the upper surface of the inviscid soil layer to be reinforced from the ground surface and the thickness s of the inviscid soil layer;
(2) preparing solution A, solution B and solution C as curing agent for microbiologically reinforcing clay without stickiness according to claim 1;
(3) vertically drilling a plurality of wells downwards on the ground surface of an inviscid soil layer to be reinforced, wherein all the wells are uniformly distributed in a matrix form at intervals of 1.5-2 m and are divided into grouting wells 1 and pumping wells 2, the pumping wells are arranged around the grouting wells, and the grouting wells are arranged around the pumping wells; and inserting a steel perforated pipe into each well, wherein the length l of the steel perforated pipe inserted into the ground is
(4) Respectively installing a grouting pipe and a water pumping pipe in the grouting well and the water pumping well in the step (3), wherein one end of the grouting pipe is connected with a steel perforated pipe in the grouting well, and the other end of the grouting pipe is connected with grouting equipment, so that a grouting system is formed; one end of the water pumping pipe is inserted into the steel perforated pipe in the water pumping well, and the other end of the water pumping pipe is connected with water pumping equipment, so that a water pumping system is formed;
as shown in figure 1, the grouting pipes and the water pumping pipes are arranged at intervals, the grouting pipes and the water pumping pipes are also arranged on two rows at intervals, and meanwhile, the grouting pipes and the water pumping pipes in the grouting system and the water pumping system can be multiple, so that the area of one-time reinforcement is larger.
(5) Grouting and reinforcing:
5.1) first grouting: after the grouting equipment in the step (4) is communicated with the solution A and the solution C, starting the grouting equipment, injecting the solution A and the solution C into a grouting well according to the volume ratio of 1:9, simultaneously starting a water pumping device, pumping out the solution I in the water pumping well, timely checking the calcium ion concentration in the solution I, stopping pumping water and grouting when the calcium ion concentration in the solution I is more than 60mg/L, and standing for 2-4 hours; theoretically, the solution I is groundwater, the solution I may contain a small amount of components of the solution A and the solution B after the solution A and the solution C are injected, and the solution A and the solution C are equivalent to replacement with groundwater after the solution I is extracted, and the inviscid soil layer is a mixed solution of the solution A and the solution C.
After the grouting equipment is communicated with the solution B, starting the grouting equipment, injecting the solution B into a grouting well, simultaneously starting the pumping equipment, pumping out the solution II in the pumping well, and simultaneously detecting OD in the solution II600Value as groundwater OD600The value is blank, if the measured solution II OD600The value is blank, if the OD of the solution II minus the blank is measured600Stopping pumping water and grouting when the value is more than 0.1, and standing for 24-48 h; at the moment, the solution II mainly comprises the solution A and the solution C, and a small amount of pasteurella, ammonium ions, carbonate ions and the like, and the solution B is added to be conveniently mixed and reacted with the solution A and the solution C.
5.2) second grouting: repeating the step 5.1), wherein the volume ratio of the solution A to the solution C in the grouting process is 1: 4;
5.3) third grouting: repeating the step 5.1), wherein the volume ratio of the solution A to the solution C in the grouting process is 1: 1;
5.4) fourth and later grouting: repeating step 5.3);
and after each grouting, detecting the content of calcium carbonate in the inviscid soil layer to be reinforced, and when the content of calcium carbonate in the inviscid soil layer to be reinforced is detected to be more than or equal to a set value, finishing the reinforcement of the inviscid soil layer in the corresponding area of the grouting well.
The high-concentration nitrite has toxicity to the anaerobic ammonium oxidation bacteria, and the toxicity threshold value is gradually increased along with the growth of the anaerobic ammonium oxidation bacteria; in the process of curing the cohesionless soil layer, the higher the calcium ion concentration is, the higher the speed of producing calcium carbonate is, and the higher the generation amount is. In order to ensure the activity of anaerobic ammonium oxidation bacteria and relatively high calcium carbonate growth rate in the strengthening process, the strengthening process is optimized by gradually increasing the calcium ion concentration in the mixed solution of the solution A and the solution C.
Wherein, the vertical error of the drilling construction plane in the step (3) is less than or equal to 80 cm.
When the solution A and the solution C are injected into the grouting well in the step (5), setting the grouting pressure of grouting equipment to be 100-300 KPa; and when the solution B is injected, setting the grouting pressure of grouting equipment to be 10-100 KPa. The solution B is injected in a low osmotic pressure mode, so that the solution B is mainly moved in the gap of the cohesionless soil layer under the diffusion action, the existing solution in the gap of the cohesionless soil layer cannot be flushed out, and the existing solution cannot be discharged out of the gap of the cohesionless soil layer in advance due to the fact that the speed is too high to form preferential flow, and the pasteurella in the solution B can be fully utilized.
Wherein the set value of the content of calcium carbonate in the step (5) is 10Kg/m3。
Wherein, the content of calcium carbonate in the inviscid soil layer in the step (5) is calculated according to the following formula:
wherein: n-the number of repeated slip casting;
a-the molar concentration of urea in solution A, mmol/L;
the content of M-calcium carbonate is Kg/M3。
Example (b):
firstly, preparation work before construction:
1. surveying to obtain the depth h of the upper surface of the inviscid soil layer to be reinforced from the ground surface to be 3m and the thickness s of the inviscid soil layer to be 5 m;
2. the method comprises the following steps that a plurality of wells are vertically drilled downwards on the ground surface of an inviscid soil layer to be reinforced, all the wells are uniformly distributed in a matrix form at intervals of 1.5m, all the wells are divided into grouting wells and pumping wells, pumping wells are arranged around the grouting wells, and grouting wells are arranged around the pumping wells; inserting a steel perforated pipe with the pipe diameter of 60mm and the wall thickness of 5mm into each well, wherein the length l of the steel perforated pipe inserted into the ground is 7 m; the vertical error of the drilling construction plane is not more than 80 cm;
3. a grouting pipe and a water pumping pipe are respectively arranged in the grouting well and the water pumping well, one end of the grouting pipe is connected with a steel perforated pipe in the grouting well, and the other end of the grouting pipe is connected with grouting equipment, so that a grouting system is formed; one end of the water pumping pipe is inserted into the steel perforated pipe in the water pumping well, and the other end of the water pumping pipe is connected with water pumping equipment, so that a water pumping system is formed.
Secondly, preparing solution A, solution B and solution C for later use
1. Solution A: the anaerobic ammonia oxidation granular sludge is taken from an anaerobic ammonia oxidation process sewage treatment plant or an EGSB reactor, 13.21g (100mmol) of industrial-grade calcium nitrite and 6.01g (100mmol) of urea are weighed and dissolved in 1L of water to prepare a solution A, and the solution A is stored in a container with a stirrer.
2. Solution B: inoculating the pasteurella to a yeast extract culture medium containing 15g of yeast extract and 10g of ammonium sulfate per liter, controlling the pH to be 9-10 by using sodium hydroxide and hydrochloric acid solution, and culturing for 20-30 hours at 30 ℃ by using a constant temperature shaking box at the rotating speed of 120r/min to obtain the pasteurella culture solution. In order to ensure the survival rate of the bacteria, the air is preferably continuously pumped. Centrifuging the culture solution, and resuspending the centrifuged bacteria with 5g/L yeast extract water solution to obtain Paenibacillus pasteurianus solution, OD of the solution600Above 2, solution B should be stored in a container with a stirrer.
3. Solution C: 4.66g of industrial-grade potassium bicarbonate, 20mg of industrial-grade potassium dihydrogen phosphate, 400mg of industrial-grade magnesium sulfate, 400mg of industrial-grade sodium chloride and 10mg of industrial-grade ferrous sulfate are weighed and dissolved in 1L of water to prepare a solution C which is ready to use.
Third, grouting and reinforcing
1. Grouting for the first time: after the grouting equipment in the step (4) is communicated with the solution A and the solution C, starting the grouting equipment, injecting the solution A and the solution C into a grouting well according to the volume ratio of 1:9, simultaneously starting a water pumping device, pumping out the solution I in the water pumping well, timely checking the calcium ion concentration in the solution I, stopping pumping water and grouting when the calcium ion concentration in the solution I is more than 60mg/L, and standing for 3 hours;
after the grouting equipment is communicated with the solution B, starting the grouting equipment, injecting the solution B into a grouting well, simultaneously starting a pumping equipment, pumping out the solution II in a pumping well, and simultaneously detecting OD in the solution II600Value as groundwater OD600The value is a blank sample, and the OD of the solution II minus the blank sample is measured600Stopping pumping water and grouting when the value is more than 0.3, and standing for 48 hours;
2. and (3) grouting for the second time: repeating the first grouting step, wherein the volume ratio of the solution A to the solution C is 1:4, and simultaneously detecting the concentration of calcium carbonate in the cohesionless soil layer to be 6Kg/m3；
3. Grouting for the third time: repeating the first grouting step, wherein the volume ratio of the solution A to the solution C is 1:1, and simultaneously detecting the concentration of calcium carbonate in the cohesionless soil layer to be 8Kg/m3；
4. Fourth grouting: repeating the third grouting step, and detecting that the concentration of the calcium carbonate in the cohesionless soil layer is 13Kg/m3And finishing the reinforcement of the reinforced area.
Finally, it should be noted that the above-mentioned examples of the present invention are only examples for illustrating the present invention, and are not intended to limit the embodiments of the present invention. Variations and modifications in other variations will occur to those skilled in the art upon reading the foregoing description. Not all embodiments are exhaustive. All obvious changes and modifications of the present invention are within the scope of the present invention.
Claims (9)
1. The method for reinforcing the cohesionless soil is characterized by comprising the following steps:
(1) surveying to obtain the depth h of the upper surface of the inviscid soil layer to be reinforced from the ground surface and the thickness s of the inviscid soil layer;
(2) preparing a solution A, a solution B and a solution C for later use, wherein the solution A is a mixed solution formed by an anaerobic ammonium oxidation bacteria solution, a urea solution and a calcium nitrite solution; the solution B is a bacillus pasteurii solution; the solution C is a mixed solution of potassium bicarbonate, potassium dihydrogen phosphate, magnesium sulfate, calcium chloride and ferrous sulfate;
(3) vertically drilling a plurality of wells downwards on the ground surface of the cohesionless soil layer to be reinforced, wherein all the wells are uniformly distributed in a matrix form at intervals of 1.5-2 m and are divided into grouting wells and pumping wells, the pumping wells are arranged around the grouting wells, and the grouting wells are arranged around the pumping wells; and inserting a steel perforated pipe into each well, wherein the length l of the steel perforated pipe inserted into the ground is
(4) Respectively installing a grouting pipe and a water pumping pipe in the grouting well and the water pumping well in the step (3), wherein one end of the grouting pipe is connected with a steel perforated pipe in the grouting well, and the other end of the grouting pipe is connected with grouting equipment; one end of the water pumping pipe is inserted into the steel perforated pipe in the water pumping well, and the other end of the water pumping pipe is connected with water pumping equipment;
(5) grouting and reinforcing:
5.1) first grouting: after the grouting equipment in the step (4) is communicated with the solution A and the solution C, starting the grouting equipment, injecting the solution A and the solution C into a grouting well according to the volume ratio of 1:9, simultaneously starting a water pumping device, pumping out the solution I in the water pumping well, timely checking the calcium ion concentration in the solution I, stopping pumping water and grouting when the calcium ion concentration in the solution I is more than 60mg/L, and standing for 2-4 hours;
after the grouting equipment is communicated with the solution B, starting the grouting equipment, injecting the solution B into a grouting well, simultaneously starting a pumping equipment, pumping out the solution II in a pumping well, and simultaneously detecting OD in the solution II600Value as groundwater OD600The value is blank, if the OD of the solution II minus the blank is measured600Stopping pumping water and grouting when the value is more than 0.1, and standing for 24-48 h;
5.2) second grouting: repeating the step 5.1), wherein the volume ratio of the solution A to the solution C in the grouting process is 1: 4;
5.3) third grouting: repeating the step 5.1), wherein the volume ratio of the solution A to the solution C in the grouting process is 1: 1;
5.4) fourth and later grouting: repeating step 5.3);
and after each grouting, detecting the content of calcium carbonate in the inviscid soil layer to be reinforced, and when the content of calcium carbonate in the inviscid soil layer to be reinforced is detected to be more than or equal to a set value, finishing the reinforcement of the inviscid soil layer in the corresponding area of the grouting well.
2. The method for reinforcing the inviscid soil according to claim 1, wherein the molar concentrations of the urea solution and the calcium nitrite solution in the solution A are equal, and the molar concentration is 10-100 mmol/L.
3. The method of claim 1, wherein the OD of the Pasteurella solution is600Greater than 2.
4. The method for reinforcing cohesive-free soil according to claim 1, wherein the concentrations of the components in the solution C are as follows: 2-5 g/L potassium bicarbonate, 40-70 mg/L potassium dihydrogen phosphate, 200-500 mg/L magnesium sulfate, 200-500 mg/L sodium chloride and 8-15 mg/L ferrous sulfate.
5. The method for consolidating inviscid soil according to claim 1, wherein the anammox bacteria solution is a solution of anammox sludge particles dissolved in water.
6. The method for consolidating inviscid soil according to claim 1, wherein the vertical deviation of the drilling construction plane in step (3) is less than or equal to 80 cm.
7. The method for reinforcing the inviscid soil according to claim 1, wherein when the solution A and the solution C are injected into the grouting well in the step (5), the grouting pressure of grouting equipment is set to be 100-300 KPa; and when the solution B is injected, setting the grouting pressure of grouting equipment to be 10-100 KPa.
8. The method for reinforcing tack-free soil according to claim 1, wherein the set value of the calcium carbonate content in the step (5) is 10Kg/m3。
9. The method for reinforcing inviscid soil according to claim 1, wherein the content of calcium carbonate in the inviscid soil layer in the step (5) is calculated according to the following formula:
wherein: n-the number of repeated slip casting;
a-the molar concentration of urea in solution A, mmol/L;
the content of M-calcium carbonate is Kg/M3。
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| CN111377627A (en) * | 2020-02-18 | 2020-07-07 | 温州大学 | Method for reinforcing residual soil by novel microbial inorganic cementing material and spraying equipment thereof |
| CN113250184B (en) * | 2021-03-31 | 2022-02-01 | 南京大学 | Combined repairing method for multi-scale fracture of rock mass based on microbial mineralization |
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