Test method for reinforcing discontinuous structural surface of rock mass of hydro-fluctuation belt by using microorganisms

Abstract

The invention relates to the field of microorganism reinforced rock-soil bodies, in particular to a test method for reinforcing a discontinuous structural surface of a hydro-fluctuation belt rock body by using microorganisms. The method comprises the following steps: sampling on site and manufacturing a fractured rock mass sample containing a through structural plane; culturing the microbial bacterial liquid, and preparing microbial sludge with urease activity; the method comprises the following steps: uniformly smearing microbial mud on a fissure surface, splicing a fissure rock mass, completely soaking the fissure rock mass in a high-concentration reaction liquid for continuous reaction, and further inducing to generate a calcium carbonate cementitious body to fill the fissure surface; and extracting the pore structure in the rock mass through a CT scanning technology, and evaluating the reinforcing effect. According to the method, the filling uniformity of the fissure surface is remarkably improved, and the problems that a traditional MICP grouting method is low in reinforcing efficiency and uneven in calcium carbonate cementation body distribution are solved. The method has the advantages of being environmentally friendly, efficient and free of pollution, and a new technical thought is provided for treatment of the three gorges reservoir area hydro-fluctuation belt fractured rock mass.

Description

Technical Field

[0001] The present invention relates to the field of microbial reinforcement of rock and soil masses, and particularly to a test method for using microorganisms to reinforce the discontinuous structural planes of the rock masses in the drawdown zone. Background Art

[0002] The rock masses in the high-steep reservoir banks' drawdown zone in the Three Gorges Reservoir area have been in a complex mechanical environment for a long time. Under the combined action of the self-weight of the overlying rock masses and the periodic fluctuations of the reservoir water, the rock masses continue to deteriorate, and the rock fissures continue to develop and expand, becoming the key disaster-causing factor inducing the instability and failure of the reservoir bank slopes in the Three Gorges Reservoir area at the present stage.

[0003] In recent years, certain progress has been made in the field of fissured rock mass reinforcement technology. Compared with the traditional grouting reinforcement and anchoring reinforcement technologies using cement materials, microbial reinforcement of rock and soil masses has become a research hotspot in the current geotechnical engineering field due to its advantages of being green, environmentally friendly, pollution-free, and having less disturbance to rock and soil masses. Microbial reinforcement of rock and soil masses generates mineral crystals through the metabolic functions of microorganisms themselves. These mineral crystals can fill the pores and fissures and cement the surrounding rock and soil masses to improve the strength of the rock and soil masses and reduce permeability. Among them, the more widely used one is the MICP (Microbially Induced Calcium Carbonate Precipitation) technology. Currently, there are few studies on using the MICP technology to reinforce fissured rock masses, and the research still remains at the indoor test stage.

[0004] The traditional MICP reinforcement method uses the idea of the grouting method, injecting the microbial bacterial solution and the reaction solution into the fissure surfaces of the rock masses respectively for reinforcement. And the traditional MICP grouting reinforcement method usually requires multiple rounds of grouting reinforcement, with low efficiency. Especially when dealing with rock masses with larger fissure surfaces or larger fissure apertures, it usually takes a long grouting time to achieve better reinforcement effects. Moreover, the calcium carbonate precipitate generated by the traditional grouting method will deposit near the grouting port, blocking the grouting channel and affecting the subsequent grouting reinforcement effect.

[0005] Based on this, the present invention proposes a new test method for using microorganisms to reinforce the discontinuous structural planes of the rock masses in the drawdown zone. Summary of the Invention

[0006] The purpose of the present invention is to solve the deficiencies existing in the prior art, and propose a test method for using microorganisms to reinforce the discontinuous structural planes of the rock masses in the drawdown zone, which uses microorganisms to induce the premature generation of calcium carbonate, prepares a solid microbial mud with urease activity to reinforce the fissured rock masses, and solves the problems of low reinforcement efficiency and uneven distribution of the generated calcium carbonate cementitious body in the traditional MICP grouting reinforcement method.

[0007] A test method for using microorganisms to reinforce the discontinuous structural planes of the rock masses in the drawdown zone includes the following steps:

[0008] Step 1: Collect fractured rock mass materials from the steep reservoir bank's water-level-fluctuation zone in the Three Gorges Reservoir Area. Use this rock mass material to make standard cylindrical specimens, and divide these standard cylindrical specimens to form a through-going structural plane.

[0009] In Step 1, the rock mass material used is sampled from the steep reservoir bank's water-level-fluctuation zone in the Three Gorges Reservoir Area. Affected by the periodic water-level fluctuations in the Three Gorges Reservoir Area, the rock mass has been in a complex mechanical environment of wet-dry cycles for a long time, resulting in varying degrees of damage and deterioration. The rock mass fractures continue to expand and develop.

[0010] Since rock samples containing natural single through-going fractures are non-replicable, in Step 1, a through-going structural plane is made inside the standard cylindrical specimen by artificial cutting. The fracture surface mentioned below refers to this through-going structural plane here.

[0011] Step 2: Add the reaction solution and water to the urease-producing bacterial solution, place it on a magnetic stirrer and continuously stir for 12 h. After the stirring is completed, filter out the upper clear liquid, and take the lower milky white precipitate, which is the microbial mud with urease activity.

[0012] Among them, the solvent of the reaction solution is water, and the solutes include: urea and water-soluble calcium salts.

[0013] In Step 2, the microbial mud is a mixed viscous substance containing the urease-producing bacterial solution and calcium carbonate precipitate, and its active ingredients are calcium carbonate crystals and urease.

[0014] Step 3: Evenly apply the product obtained in Step 2 on the through-going structural plane of the standard cylindrical specimen, then assemble and tie it to maintain the fixation of the standard cylindrical specimen, and scrape off the product obtained in Step 2 that overflows from the structural plane.

[0015] Step 4: Completely immerse the fixed standard cylindrical specimen in the reaction solution for curing.

[0016] Step 5: Conduct a CT scan on the cured standard cylindrical specimen, obtain the pore data inside the specimen and construct a three-dimensional visualization model to evaluate the reinforcement effect.

[0017] Preferably, in Step 1, the size of the standard cylindrical specimen is Φ50mm×100mm.

[0018] Preferably, in Step 2, the materials in the urease-producing bacterial solution include: Sarcina pasteurii.

[0019] Preferably, in Step 2, the urease-producing bacterial solution is obtained by inoculating and culturing in a liquid medium; the liquid medium includes: 20 g / L of yeast extract, 15 g / L of ammonium chloride, and 0.01 g / L of nickel chloride.

[0020] Preferably, in Step 2, the strains in the urease-producing bacterial solution include: Sarcina pasteurii, Bacillus licheniformis, Bacillus natto.

[0021] Preferably, in step two, the urease activity in the urease-producing bacterial solution is ≥ 0.1 ms / (cm·min), and its absorbance OD 600 is 1.2 - 1.4.

[0022] Preferably, in step two, the molar concentrations of urea and calcium ions in the reaction solution are equal.

[0023] Preferably, in step two, in the system after mixing the urease-producing bacterial solution and the reaction solution, the urea concentration is 0.35 - 0.45 mol / L.

[0024] Preferably, in step two, the water-soluble calcium salt is at least one of calcium chloride, calcium acetate, and calcium nitrate.

[0025] Preferably, in step two, the solute in the reaction solution further includes: lanthanum chloride, and the concentration ratio of lanthanum chloride to urea is 0.01 - 0.05:1.

[0026] Since Sporosarcina pasteurii is an aerobic bacterium, while Bacillus licheniformis is a facultative anaerobic microorganism, the combination of the two can continue mineralization even in an anoxic environment. Combined with the action of Bacillus natto, the adaptability of the system under different environmental conditions is enhanced, and the stability of the mineralization ability is improved; combined with the action of lanthanum chloride, the adaptability of microorganisms in different environments is significantly enhanced, ensuring the continuous reaction of the biological mud with urease activity in the rock mass fissures and stably inducing the formation of calcium carbonate cement.

[0027] Preferably, step two further includes the following steps: adding sodium alginate and tetraethyl orthosilicate to water, stirring at 80 - 90 °C for 10 - 20 min, adding acetic acid thereto under stirring, stirring for 1 - 2 h, adding sodium bicarbonate thereto, stirring at 90 - 95 °C for 10 - 20 min, freeze-drying, pulverizing and adding to water, then adding calcium lactate and performing ultrasonic treatment for 10 - 30 min, and adding biological mud thereto and stirring evenly.

[0028] The present invention uses the compounding of sodium alginate and tetraethyl orthosilicate to form a composite sol, forms a porous structure with sodium bicarbonate therein, is cross-linked and stabilized by calcium lactate after freeze-drying, so that the formed porous gel structure is not easy to collapse, and can better load the biological mud. When used for smearing rock mass fissures, it not only has better stability on the cracks, promotes the cracks to be cemented into one body, but also the uniformly distributed porous structure is more conducive to the subsequent reaction solution to continuously enter the interior of the cracks for further cementation to reduce the permeability.

[0029] More preferably, the mass ratio of sodium alginate, tetraethyl orthosilicate, acetic acid, sodium bicarbonate, calcium lactate, and biological mud is 1 - 2:1 - 4:1 - 3:1 - 2:1 - 3:20 - 40.

[0030] Preferably, in Step 3, the product obtained in Step 2 is evenly applied and then left standing for 2 - 3 min. After the water evaporates and the fluidity of the product weakens, assembly is carried out.

[0031] Preferably, in Step 3, a rubber band is used for tying to provide circumferential restraint and prevent the product obtained in Step 2 from overflowing from the structural plane.

[0032] Preferably, in Step 4, the urea concentration in the reaction solution > 4 mol / L.

[0033] Preferably, in Step 4, the curing time ≥ 72 h.

[0034] In Step 5, as a non - destructive testing method, CT scanning can evaluate the filling and reinforcement effect of microbial mud on the microscopic pores of the fracture surface from the mesoscopic scale.

[0035] Beneficial effects:

[0036] The present invention uses a microbial product with urease activity to reinforce the fractured rock mass specimens in the water - level - fluctuating zone of a high - steep reservoir bank, cementing the fractured rock samples into a whole, which is a new type of green and pollution - free reinforcement technology.

[0037] Compared with MICP grouting reinforcement, the microbial mud method solves the problems of low grouting efficiency and uneven distribution of the generated calcium carbonate cementing body. Moreover, the rock mass in the water - level - fluctuating zone of the reservoir bank is affected by the periodic fluctuation of the reservoir water for a long time and has high requirements for impermeability. The fractured rock samples reinforced by the microbial mud technology can effectively reduce the permeability, and the improvement of the anti - seepage performance far exceeds that of the traditional MICP reinforcement. Description of the drawings

[0038] Figure 1 It is a flow schematic diagram of Example 1.

[0039] Figure 2 It is a whole - picture photo of the water - level - fluctuating zone fractured rock mass specimen with a through - type structural plane obtained in Example 1.

[0040] Figure 3 It is a photo of the disassembled water - level - fluctuating zone fractured rock mass specimen with a through - type structural plane obtained in Example 1.

[0041] Figure 4 It is a photo of the microbial bacterial solution obtained in Example 1.

[0042] Figure 5 It is a photo of magnetic stirring of the microbial bacterial solution and the reaction solution in Example 1.

[0043] Figure 6 It is a photo of the layered state after magnetic stirring of the microbial bacterial solution and the reaction solution in Example 1.

[0044] Figure 7Photo of the microbial mud obtained in Step 2 of Example 1 evenly smeared on the rock mass fracture surface.

[0045] Figure 8 Photo of the fractured rock mass specimen after reinforcement in Example 1.

[0046] Figure 9 CT scan image of the fractured rock mass specimen after reinforcement in Example 1.

[0047] Figure 10 CT scan image of the fractured rock mass specimen after grouting reinforcement in Comparative Example 1. Detailed implementation manners

[0048] The present invention will be further explained below in conjunction with specific embodiments.

[0049] Example 1

[0050] As Figure 1 shown, this example provides a method for reinforcing the fractured rock mass specimen in the drawdown zone using microbial mud. Specifically, it includes the following steps:

[0051] Step 1: Collect rock mass specimens from the drawdown zone of the reservoir bank in Wushan section of the Three Gorges Reservoir area on-site. According to the specification requirements of GB / T 50266 - 2013 "Standard for Test Methods of Engineering Rock Masses", the collected rock masses are made into standard cylindrical specimens with a diameter of Φ50mm and a height of 100mm, and a through fracture is pre-cut in the middle of the rock mass specimen. The obtained fractured rock mass specimens are as Figure 2 and Figure 3 shown.

[0052] Step 2: Dissolve 20g / L yeast extract, 15g / L ammonium chloride, and 0.01g / L nickel chloride in an appropriate amount of ultrapure water to prepare a liquid medium; select Sporosarcina pasteurii as the urease-producing bacterium, inoculate and expand it in the liquid medium, and store it refrigerated; dissolve 4mol / L urea and 4mol / L calcium chloride in an appropriate amount of ultrapure water to prepare a reaction solution for standby.

[0053] Measure the urease activity and the number of microorganisms of the Sporosarcina pasteurii bacterial solution with mineralization ability obtained by cultivation through a conductivity meter and a spectrophotometer. The urease activity is controlled above 0.1ms / (cm·min), and the absorbance OD 600 is controlled between 1.2 - 1.4. The cultivated microbial bacterial solution is as Figure 4 shown.

[0054] Add the reaction solution and water to the microbial bacterial solution to make the urea concentration in the system 0.44mol / L, and place it on a magnetic stirrer and continuously stir for 12h, as Figure 5As shown, during the stirring process, the urease produced by the microbial bacterial solution comes into full contact with urea and continuously hydrolyzes to generate carbonate ions. At the same time, the hydrolysis of urea keeps the solution in an alkaline environment all the time. The carbonate ions react with the calcium ions provided by calcium chloride in the alkaline environment to form calcium carbonate crystal precipitates; after the stirring is completed, as Figure 6 shown, the upper clear liquid is filtered out, and the lower milky white precipitate is the microbial mud with urease activity, and its effective components are calcium carbonate crystals and urease.

[0055] Step 3: As Figure 7 shown, evenly apply the microbial mud obtained in Step 2 on the rock mass fracture surface. After standing for 2 - 3 minutes, butt and join the two rock masses together, use a rubber band to fix the position of the rock mass to ensure proper splicing, and scrape off the microbial mud overflowing from the fracture surface.

[0056] Step 4: Immerse the ligated fractured rock mass specimen completely in a 4mol / L reaction solution for 72h, so that the microbial mud with urease activity in the rock mass fractures continues to react, and further induces the formation of calcium carbonate cementing bodies. The completed reinforced fractured rock mass specimen is as Figure 8 shown.

[0057] Step 5: Conduct a CT scan experiment on the reinforced fractured rock mass specimen, construct a three-dimensional visualization model based on the CT scan gray data, extract the internal pore structure of the fractured rock mass specimen, calculate the overall porosity and connectivity before and after microbial reinforcement, and compare and analyze the effect of microbial reinforcement.

[0058] In this embodiment, the overall porosity of the fractured rock mass before microbial mud reinforcement is 4.303%, the fracture structural plane is overall connected, and the isolated porosity is only 0.053%; after microbial mud reinforcement, the fracture structural plane of the fractured rock mass is overall filled with the generated calcium carbonate cementing bodies, and the overall porosity is reduced to 1.413%. At the same time, the original connected pores are cut into isolated pores by the cementing bodies, there are no connected pores in the fracture plane, and no effective seepage channels can be formed inside the rock mass, so the anti-seepage performance of the rock mass is greatly improved.

[0059] Comparative Example 1

[0060] In this comparative example, the conventional MICP grouting reinforcement method is used to reinforce the drawdown zone fractured rock mass specimen. For comparison, the fractured rock mass specimen used in this comparative example is from the same batch as that in Example 1, and the microbial bacterial solution used is also the same as that in Example 1.

[0061] In this comparative example, a BT101LY peristaltic pump was used to inject the microbial solution and the cementing solution into the rock mass fissures through different grouting channels. First, 10 mL of the microbial solution was injected at a rate of 1 mL / min. After standing for a period of time until the microorganisms were evenly distributed in the fissures, an equal amount of the cementing solution was slowly injected at a rate of 1 mL / min to allow them to fully react within the rock mass fissures, generating calcium carbonate crystal precipitates at the bottom of the fissures. After the microbial solution and the cementing solution fully reacted in the rock mass fissures to form calcium carbonate precipitates, the excess waste liquid was discharged, and 10 mL of the microbial solution and the cementing solution were injected again, causing the induced calcium carbonate precipitates to gradually deposit at the bottom of the fissures. The above steps were repeated until the entire rock mass fissure surface was filled and cemented with calcium carbonate precipitates.

[0062] The fissured rock mass specimens after grouting reinforcement were also subjected to CT scanning to extract the internal pore structure and construct a three-dimensional visualization model.

[0063] Before reinforcement in this comparative example, the overall porosity of the fissured rock mass was 5.096%, and the fissure surface was overall through; after reinforcement, the overall porosity decreased to 4.204%. Due to the cutting of the through pores by the cementitious body, the isolated porosity increased to 0.003%.

[0064] After reinforcement using the method of Example 1, the overall porosity of the fissured rock mass decreased more and the proportion of isolated pores was larger, indicating that the method of the present invention has a better filling effect on the internal pores of the fissured rock mass; moreover, the method of the present invention is more convenient to operate, does not require multiple grouting operations on the fissure surface, has a shorter reinforcement period, and higher reinforcement efficiency.

[0065] After the CT scans of the drawdown zone fissured rock mass specimens reinforced in Example 1 and Comparative Example 1, the visualized images of the fissure surfaces constructed were respectively as Figure 9 、 Figure 10 shown. Through comparison, it was found that: in Comparative Example 1, most of the calcium carbonate cementitious bodies generated by grouting reinforcement were deposited at the bottom of the fissure surface, and the distribution of the cementitious bodies in the upper half of the fissure surface was very uneven; while the calcium carbonate cementitious bodies induced by the method of the present invention were evenly distributed within the fissure surface, could well fill and cement the fissured rock mass specimens, block the seepage channels, greatly improve the anti-seepage ability of the fissured rock mass, and have a better reinforcement effect.

[0066] Example 2

[0067] The difference from Example 1 is that:

[0068] (1) In step two, Sporosarcina pasteurii, Bacillus licheniformis, and Bacillus natto were respectively inoculated and cultured and then mixed to obtain a urease-producing bacterial solution, where the viable cell numbers ratio of Sporosarcina pasteurii, Bacillus licheniformis, and Bacillus natto was 11:6:3;

[0069] (2) In Step 2, the solutes in the reaction solution consist of urea, calcium chloride, and lanthanum chloride, and the concentration of lanthanum chloride is 0.1 mol / L.

[0070] Before reinforcement in this example, the overall porosity of the fractured rock mass was 4.587%, the fracture structural planes were overall connected, and the isolated porosity was 0.061%; after reinforcement with microbial mud, the fracture structural planes of the fractured rock mass were overall filled with the generated calcium carbonate cement, the overall porosity decreased to 1.256%, and the isolated porosity increased to 0.192%.

[0071] Comparative Example 2

[0072] The difference from Example 2 is that only Sporosarcina pasteurii and Bacillus licheniformis were respectively inoculated and cultured and then mixed to obtain a urease-producing bacterial solution, and the ratio of the viable cell numbers of Sporosarcina pasteurii to Bacillus licheniformis was 11:6.

[0073] Before reinforcement in this comparative example, the overall porosity of the fractured rock mass was 4.787%, the fracture structural planes were overall connected, and the isolated porosity was 0.055%; after reinforcement with microbial mud, the fracture structural planes of the fractured rock mass were overall filled with the generated calcium carbonate cement, the overall porosity decreased to 2.035%, and the isolated porosity increased to 0.079%.

[0074] Comparison between Example 2 and Comparative Example 2 shows that: using the method of Example 2 results in a greater decrease in the overall porosity, and can effectively block the seepage channels, cut the connected pores, increase the isolated porosity to a greater extent, and greatly improve the anti-seepage ability of the fractured rock mass, with better reinforcement effect.

[0075] Example 3

[0076] The difference from Example 2 is that in Step 2, the microbial mud was further processed, and in Step 3, the further processed product of the microbial mud was smeared on the connected structural planes of the standard cylindrical specimens.

[0077] The specific steps for further processing with the microbial mud in this example are as follows: By mass, 1.5 parts of sodium alginate and 2.5 parts of tetraethyl orthosilicate were added to 45 parts of water, stirred at 85°C for 15 min with a stirring speed of 600 r / min. 2 parts of acetic acid were added under stirring, and stirring continued for 90 min. 1.5 parts of sodium bicarbonate were added, stirred at 92°C for 15 min, freeze-dried, pulverized, and then added to 30 parts of water. 2 parts of calcium lactate were added and ultrasonic treated for 20 min with an ultrasonic frequency of 4.5 kHz. 30 parts of microbial mud were added and stirred evenly.

[0078] Before reinforcement in this example, the overall porosity of the fractured rock mass was 4.691%, the fracture structural planes were overall connected, and the isolated porosity was 0.059%. After reinforcement with microbial mud, the fracture structural planes of the fractured rock mass were overall filled with the generated calcium carbonate cementing body, the overall porosity decreased to 1.003%, and the isolated porosity increased to 0.237%.

[0079] Comparative Example 3

[0080] The difference from Example 3 lies in that the further treatment method using microbial mud is inconsistent.

[0081] The specific steps for further treatment with microbial mud in this comparative example are as follows: By mass, add 1.5 parts of sodium alginate and 2.5 parts of tetraethyl orthosilicate to 45 parts of water, stir at 85°C for 15 min, with a stirring speed of 600 r / min. Add 2 parts of acetic acid thereto under stirring, continue stirring for 90 min, freeze-dry, pulverize and add to 30 parts of water. Add 2 parts of calcium lactate thereto and perform ultrasonic treatment for 20 min, with an ultrasonic frequency of 4.5 kHz. Add 30 parts of microbial mud thereto and stir evenly.

[0082] Before reinforcement in this comparative example, the overall porosity of the fractured rock mass was 4.912%, the fracture structural planes were overall connected, and the isolated porosity was 0.070%. After reinforcement with microbial mud, the fracture structural planes of the fractured rock mass were overall filled with the generated calcium carbonate cementing body, the overall porosity decreased to 1.178%, and the isolated porosity increased to 0.135%.

[0083] As described above, it is only the preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and all should be covered within the protection scope of the present invention.

Claims

1. An experimental method for strengthening discontinuous structural planes of rock masses in the water-level-fluctuation zone using microorganisms, characterized in that, It includes the following steps: Step 1: Collect fractured rock mass materials in the drawdown zone of high-steep reservoir banks, use the rock mass materials to make standard cylindrical specimens, and divide the standard cylindrical specimens to form through-going structural planes; Step 2: Continuously stir by adding a reaction solution and water to the urease-producing bacterial solution, and filter to obtain microbial mud; Among them, the solvent of the reaction solution is water, and the solutes include: urea and water-soluble calcium salts; Step 3: Uniformly apply the product obtained in Step 2 on the through-going structural planes of the standard cylindrical specimens, then maintain and fix the standard cylindrical specimens, and scrape off the product obtained in Step 2 that overflows from the structural planes; Step 4: Completely immerse the fixed standard cylindrical specimens in the reaction solution for curing; Step 5: Perform CT scanning on the cured standard cylindrical specimens, obtain the internal pore data of the specimens and construct a three-dimensional visualization model to evaluate the reinforcement effect.

2. The test method for using microorganisms to reinforce discontinuous structural planes of the rock mass in the drawdown zone according to claim 1, wherein, In Step 1, the size of the standard cylindrical specimen is Φ50mm×100mm.

3. The test method for using microorganisms to reinforce the discontinuous structural planes of the rock mass in the water-level-fluctuation zone according to claim 1, characterized in that, In Step 2, the bacterial species in the urease-producing bacterial solution include: Sarcina pasteurii.

4. The test method for using microorganisms to reinforce the discontinuous structural planes of the rock mass in the drawdown zone according to claim 1, wherein, In Step 2, the bacterial species in the urease-producing bacterial solution include: Bacillus licheniformis, Bacillus natto.

5. The test method for using microorganisms to reinforce discontinuous structural planes of rock masses in the water-level-fluctuation zone according to claim 1, characterized in that In step two, the urease activity in the urease-producing bacteria solution is ≥ 0.1 ms / (cm·min), and its absorbance OD 600 is 1.2 - 1.

4.

6. The test method for using microorganisms to reinforce the discontinuous structural planes of the rock mass in the drawdown zone according to claim 1, characterized in that In Step 2, the molar concentrations of urea and calcium ions in the reaction solution are equal.

7. The test method for using microorganisms to reinforce the discontinuous structural planes of the rock mass in the drawdown zone according to claim 1, characterized in that, In Step 2, in the system after mixing the urease-producing bacterial solution and the reaction solution, the urea concentration is 0.35 - 0.45mol / L.

8. The test method for using microorganisms to reinforce the discontinuous structural planes of the rock mass in the drawdown zone according to claim 1, characterized in that, Step 2 also includes the following steps: Add sodium alginate and tetraethyl orthosilicate to water, stir at 80 - 90°C for 10 - 20min, add acetic acid thereto under stirring, stir for 1 - 2h, add sodium bicarbonate thereto, stir at 90 - 95°C for 10 - 20min, freeze-dry, pulverize and add to water, then add calcium lactate and perform ultrasonic treatment for 10 - 30min, and add microbial mud and stir evenly.

9. The test method for using microorganisms to reinforce the discontinuous structural planes of the rock mass in the drawdown zone according to claim 8, characterized in that, The mass ratio of sodium alginate, tetraethyl orthosilicate, acetic acid, sodium bicarbonate, calcium lactate, and microbial mud is 1 - 2:1 - 4:1 - 3:1 - 2:1 - 3:20 - 40.

10. The test method for using microorganisms to reinforce the discontinuous structural planes of the rock mass in the water-level-fluctuation zone according to claim 1, wherein In Step 4, the urea concentration in the reaction solution > 4mol / L.

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