A loess foundation settlement repair material and method based on microbial nanotechnology

Abstract

The present application relates to the field of soil remediation, and more particularly to a loess foundation settlement repair material and method based on microbial nanotechnology. The loess foundation settlement repair material is a microbial nanocomposite slurry, and the components and functions of the microbial nanocomposite slurry are as follows: bacillus pasteurii for secreting calcium carbonate glue to realize soil into particles; nano-SiO2 for filling pores and enhancing creep resistance; and business liquid for maintaining microbial activity. The beneficial effects are as follows: the total settlement can be reduced by 41.5%, the secondary consolidation coefficient can be reduced by 46.7%, and the bearing capacity can be increased by 46.7%.

Description

Technical Field

[0001] This invention relates to the field of soil remediation, and more particularly to a loess foundation settlement repair material and method based on microbial nanotechnology. Background Technology

[0002] Existing foundation treatment technologies have several significant drawbacks and limitations. First, traditional dynamic compaction methods have a clear limitation on the depth of foundation treatment, typically not exceeding 10 meters. Furthermore, dynamic compaction generates strong vibrations during construction, which may damage surrounding structures and pose safety hazards. Second, while chemical grouting materials can effectively reinforce foundations in certain situations, their use carries potential environmental pollution risks. Some chemical components in chemical grouting materials may pollute soil and groundwater, impacting environmental sustainability. More importantly, chemical grouting materials cannot effectively inhibit secondary consolidation creep under long-term loads, potentially affecting the long-term stability and bearing capacity of the foundation. Finally, while existing drainage consolidation methods can accelerate the primary consolidation settlement process, thus shortening the construction period, this method often exacerbates secondary consolidation deformation. Secondary consolidation deformation refers to the slow deformation of the soil under continuous loads after primary consolidation, which may adversely affect the long-term stability and performance of buildings. Therefore, while improving construction efficiency, the existing drainage consolidation method also needs to address the challenges posed by secondary consolidation deformation.

[0003] CN119101631A, "Bacillus pasteurellii and its applications," discloses a strain of Bacillus pasteurellii, deposited at the China Center for Type Culture Collection (CCTCC M 20241864). The study utilizes ambient pressure, room temperature plasma technology to successfully screen a urease-inducing bacterial mutant strain, which significantly enhances the ability to induce calcium carbonate precipitation. This strain can be used to improve the mineralization efficiency of microbially induced calcium carbonate deposition and the soil consolidation effect. An improved kinetic model of bacterial-mediated microbial induced mineralization reaction is established, and an improved process and method for soil consolidation using this strain are proposed to address the need for efficient control of ammonium emissions.

[0004] However, this technology does not contain nano-silica, making it impossible to achieve foundation reinforcement in segments. Foundation reinforcement also needs to take settlement into account.

[0005] On July 27, 2025, using "Bacillus pasteurellii and silica and nano" as the abstract keywords and selecting the option to allow synonym expansion, a search was conducted in the China Patent Publication Database. CN108753253A, a waste rubber pulverizing grinding aid, belongs to the field of rubber pulverizing grinding technology.

[0006] On July 27, 2025, an abstract search was conducted on CNKI using the keywords "Bacillus pasteurellii and silica and nanomaterials". Wang Jing published "The impact of Bacillus pasteurellii on the remediation of cadmium-contaminated soil in the Yellow River beach area and the cadmium enrichment in winter wheat" on June 1, 2024.

[0007] On July 27, 2025, a search was conducted on the website of the United States Patent and Trademark Office for "Bacillus subtilis with silica with nanotechnology", but no relevant literature was found; the search URL is https: / / ppubs.uspto.gov / pubwebapp / .

[0008] On July 27, 2025, a search was conducted on the website of the Japan Patent Office (https: / / www.j-platpat.inpit.go.jp / ) for the search term "Bacillus subtilis and silica and nanotechnology", but no relevant literature was found. Summary of the Invention

[0009] Purpose of the invention: To provide a more effective loess foundation settlement repair material and method based on microbial nanotechnology, the specific purpose of which is described in the detailed implementation section for several substantial technical effects.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] A loess foundation settlement repair material based on microbial nanotechnology is characterized in that the loess foundation settlement repair material is a microbial nanocomposite slurry, the components and functions of which are as follows:

[0012] Bacillus pasteurellii is used to secrete calcium carbonate gel, thereby enabling soil to granulate.

[0013] Nano-SiO2 used to fill pores and enhance creep resistance;

[0014] Operating liquids used to maintain the activity of microorganisms.

[0015] A further technical solution of the present invention is that the amount of Pasteurella multocida is 10^6 CFU / mL.

[0016] A further technical solution of the present invention is that the weight percentage of nano-SiO2 in the overall slurry is 3-5 wt%.

[0017] A further technical solution of the present invention is that the operating liquid is 5g / L glucose.

[0018] A further technical solution of the present invention is that the microbial nanocomposite slurry is a slow-setting slurry, wherein 0.1% by weight of polyacrylamide is added, which can extend the main consolidation time to 1.5-2 times the design value.

[0019] A further technical solution of the present invention is that the microbial nanocomposite slurry is an injection-promoting slurry, wherein 0.05% by weight of calcium chloride is added to the slurry, which can accelerate the completion of the remaining solidification.

[0020] A method for repairing loess foundation settlement based on microbial nanotechnology, characterized by utilizing the loess foundation settlement repair material described above, and comprising the following steps:

[0021] Phase I (0-30 days): Inject a retarding grout containing 0.1% polyacrylamide to extend the primary consolidation time to 1.5-2 times the design value;

[0022] Phase II (31-60 days): Inject coagulation-promoting slurry containing 0.05% calcium chloride to accelerate the completion of the remaining consolidation;

[0023] Phase III (starting from day 61): Periodically supplement the nutrient solution to maintain the continuous microbial mineralization process.

[0024] A further technical solution of the present invention is that when the settling rate is detected to be >0.1mm / d, a grouting command is automatically triggered.

[0025] A further technical solution of the present invention is that the settling rate is monitored by a monitoring and control system, and a distributed optical fiber sensor network with a spacing of ≤2m is used to monitor strain and temperature in real time.

[0026] A further technical solution of the present invention is that the distributed optical fiber sensor network with a spacing of ≤2m is an optical fiber sensor array based on Brillouin scattering. The optical fiber sensor array based on Brillouin scattering and the automatic grouting system can be linked together. The slow-release grout can be automatically injected through the linkage device. The automatic grouting system includes a pump and a container. The pump is located in the container, and the grout is periodically added to the container. The pump is an Internet of Things pump.

[0027] The present invention, which adopts the above technical solution, has the following beneficial effects compared with the prior art: it can reduce the total settlement by 41.5%, the secondary consolidation coefficient by 46.7%, and the bearing capacity by 46.7%. Attached Figure Description

[0028] To further illustrate the present invention, the following description is provided in conjunction with the accompanying drawings:

[0029] Figure 1 The flowchart is for the invention. Detailed Implementation

[0030] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0031] This patent describes a method for controlling loess foundation settlement that combines microbial mineralization with nanomaterial modification. It is applicable to the treatment of building foundations, roadbeds, and water conservancy project foundations in collapsible loess areas.

[0032] (1) Core processing technology

[0033] Microbial-nano composite slurry formulation

[0034] | Components | Ratio | Functional Description |

[0035] | Bacillus pasteurellii | 10^6 CFU / mL | Secretes calcium carbonate cemented soil particles |

[0036] | Nano SiO2 | 3-5wt% | Fills pores and enhances creep resistance |

[0037] | Nutrient solution | Glucose 5g / L | To maintain microbial activity |

[0038] (2) Phased construction method

[0039] Phase I (0-30 days): Inject retarded grout (with 0.1% polyacrylamide added) to extend the primary consolidation time to 1.5-2 times the design value.

[0040] Phase II (31-60 days): Inject coagulating slurry (containing 0.05% calcium chloride) to accelerate the completion of the remaining consolidation.

[0041] Phase III (starting from day 61): Periodically supplement with nutrient solution to maintain continuous microbial mineralization.

[0042] (3) Monitoring and control system

[0043] Distributed fiber optic sensor network (spacing ≤ 2m) for real-time monitoring of strain / temperature

[0044] When the settling rate is detected to be greater than 0.1 mm / d, a grouting command is automatically triggered.

[0045] (3) Examples

[0046] Comparison of foundation treatment effects for a high-rise building in Lanzhou:

[0047] The indicators of this invention and the traditional dynamic compaction method are as follows: annual total settlement 48mm (originally 82mm, reduced by 41.5%), secondary consolidation coefficient 0.008 (originally 0.015, reduced by 46.7%), and bearing capacity 220kPa (originally 150kPa, increased by 46.7%).

[0048] Example 1: Combining Figure 1 A loess foundation settlement repair material based on microbial nanotechnology, characterized in that the loess foundation settlement repair material is a microbial nanocomposite slurry, the components and functions of which are as follows:

[0049] Bacillus pasteurellii is used to secrete calcium carbonate gel, thereby enabling soil to granulate.

[0050] Nano-SiO2 used to fill pores and enhance creep resistance;

[0051] A working liquid used to maintain microbial activity. The substantive technical effects and implementation process of the technical solution described herein, i.e., its basic functions, are as follows:

[0052] The concentration of Pasteurella multocida was 10^6 CFU / mL.

[0053] The weight percentage of nano-SiO2 in the overall slurry is 3-5 wt%.

[0054] The serving liquid is 5g / L glucose.

[0055] As an alternative, more nutrients can be added, but basic glucose is sufficient and will not produce gas or create weak gaps in the overall structure.

[0056] Example 2: As a further improvement, parallel, or optional independent solution, the microbial nanocomposite slurry is a slow-setting slurry, which contains 0.1% polyacrylamide by weight of the total slurry, which can extend the main consolidation time to 1.5-2 times the design value.

[0057] The microbial nanocomposite slurry is an injection-promoting slurry, which contains 0.05% calcium chloride by weight of the total slurry, which can accelerate the completion of the remaining consolidation.

[0058] The substantive technical effects and implementation process of the technical solution presented herein, i.e., its basic functions, are as follows: A *Bacillus pasteurellii*-nano silica composite curing system has been developed; a "delay-accelerate" consolidation control strategy is adopted, resulting in more stable strength.

[0059] Example 3: As a further possible improvement, parallel solution, or optional independent solution, a method for repairing loess foundation settlement based on microbial nanotechnology is characterized by utilizing the loess foundation settlement repair material described above, and comprising the following steps:

[0060] Phase I (0-30 days): Inject a retarding grout containing 0.1% polyacrylamide to extend the primary consolidation time to 1.5-2 times the design value;

[0061] Phase II (31-60 days): Inject coagulation-promoting slurry containing 0.05% calcium chloride to accelerate the completion of the remaining consolidation;

[0062] Phase III (starting from day 61): Periodically supplement the nutrient solution to maintain the continuous microbial mineralization process.

[0063] Example 4: As a further improvement, parallel, or optional independent solution, a grouting command is automatically triggered when the settling rate is detected to be >0.1 mm / d. The settling rate is monitored by a monitoring and control system, using a distributed fiber optic sensor network with a spacing ≤2m to monitor strain and temperature in real time. The distributed fiber optic sensor network with a spacing ≤2m is a Brillouin scattering-based fiber optic sensor array. The Brillouin scattering fiber optic sensor array and the automatic grouting system can be linked, and the slow-release grout can be automatically injected through the linkage device. The automatic grouting system includes a pump and a container. The pump is located in the container, and the grout is periodically added to the container. This pump is an IoT pump.

[0064] The substantive technical effects and implementation process of the technical solution presented here, i.e., its basic functions, are as follows: Higher degree of automation, enabling intelligent construction site control. The injection volume can be flexibly controlled based on the underground space to be sealed.

[0065] In summary: a synergistic composition of Bacillus pasteurellii and surface-modified nano-SiO2.

[0066] A staged grouting process is adopted to achieve controllable adjustment of the consolidation rate.

[0067] A fiber optic sensing array based on Brillouin scattering and an automatic grouting linkage device.

[0068] Innovatively, each of the above effects exists independently, yet a single structure can be used to combine the results.

[0069] It should be noted that the multiple modules in this patent are an integration of existing technology modules and do not involve any new modules. Even if some modules use programs, those programs are undoubtedly known programs.

[0070] It should be noted that the multiple solutions provided in this patent include their own basic solutions, which are independent of each other and do not restrict each other. However, they can also be combined with each other without conflict to achieve multiple effects.

[0071] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims.

Claims

1. A loess foundation settlement repair material based on microbial nanotechnology, characterized in that, The loess foundation settlement repair material is a microbial nanocomposite slurry. The components and functions of the microbial nanocomposite slurry are as follows: Bacillus pasteurellii is used to secrete calcium carbonate gel, thereby enabling soil to granulate. Nano-SiO2 used to fill pores and enhance creep resistance; Operating liquids used to maintain the activity of microorganisms.

2. The loess foundation settlement repair material based on microbial nanotechnology as described in claim 1, characterized in that, The concentration of Pasteurella multocida was 10^6 CFU / mL.

3. The loess foundation settlement repair material based on microbial nanotechnology as described in claim 1, characterized in that, The weight percentage of nano-SiO2 in the overall slurry is 3-5 wt%.

4. The loess foundation settlement repair material based on microbial nanotechnology as described in claim 1, characterized in that, The serving liquid is 5g / L glucose.

5. The loess foundation settlement repair material based on microbial nanotechnology as described in claim 1, characterized in that, The microbial nanocomposite slurry is a slow-setting slurry, which contains 0.1% polyacrylamide by weight of the total slurry, which can extend the main consolidation time to 1.5-2 times the design value.

6. The loess foundation settlement repair material based on microbial nanotechnology as described in claim 1, characterized in that, The microbial nanocomposite slurry is an injection-promoting slurry, which contains 0.05% calcium chloride by weight of the total slurry, which can accelerate the completion of the remaining consolidation.

7. A method for repairing loess foundation settlement based on microbial nanotechnology, characterized in that, The loess foundation settlement repair material according to claims 1-6 comprises the following steps: Phase I (0-30 days): Inject a retarding grout containing 0.1% polyacrylamide to extend the primary consolidation time to 1.5-2 times the design value; Phase II (31-60 days): Inject coagulation-promoting slurry containing 0.05% calcium chloride to accelerate the completion of the remaining consolidation; Phase III (starting from day 61): Periodically supplement the nutrient solution to maintain the continuous microbial mineralization process.

8. The method for repairing loess foundation settlement based on microbial nanotechnology as described in claim 7, characterized in that, When the settling rate is detected to be greater than 0.1 mm / d, a grouting command is automatically triggered.

9. A method for repairing loess foundation settlement based on microbial nanotechnology as described in claim 8, characterized in that, Settlement rate is monitored by a monitoring and control system, which uses a distributed fiber optic sensor network with a spacing of ≤2m to monitor strain and temperature in real time.

10. A method for repairing loess foundation settlement based on microbial nanotechnology as described in claim 9, characterized in that, The distributed optical fiber sensor network with a spacing of ≤2m is a Brillouin scattering-based optical fiber sensor array. The Brillouin scattering optical fiber sensor array and the automatic grouting system can be linked together. The slow-release grout can be automatically injected through the linkage device. The automatic grouting system includes a pump and a container. The pump is located in the container, and the grout is periodically added to the container. This pump is an Internet of Things (IoT) pump.

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