Reinforcement system and method for islands based on temperature-controlled micp

Abstract

The application discloses an island reef reinforcement system and method based on temperature control MICP. The system comprises a xanthan gum liquid tank, a constant low-temperature storage tank, a bacteria liquid tank and a reaction liquid tank arranged in the constant low-temperature storage tank, a constant-temperature storage tank, a mixed liquid tank arranged in the constant-temperature storage tank, a solar heat accumulator used for keeping the constant-temperature storage tank at constant temperature, a peristaltic pump, a water injection pipe, a drainage pipe, a liquid discharge channel arranged between the water injection pipe and the drainage pipe, a water collecting tank and a vacuum pump, and the constant low-temperature storage tank is kept at low temperature by using a groundwater pumping device. The elements are connected through valves and pipelines to realize the following processes: the mixed liquid tank at a required temperature is injected into an island reef to be reinforced to complete a first reinforcement by MICP induction, xanthan gum liquid is injected to complete a second reinforcement, and the liquid in the island reef to be reinforced is pumped out to realize a third reinforcement of the island reef. The application introduces the "temperature control MICP method" process into the protection engineering of large island reef reinforcement, and simultaneously realizes the multiple cycle reinforcement of the island reef by combining with the xanthan gum consolidation and the dry consolidation method.

Description

Technical Field

[0001] This invention belongs to the field of large-scale island and reef reinforcement technology, specifically relating to an island and reef reinforcement system and method based on temperature-controlled MICP. Background Technology

[0002] Because the main component of islands and reefs is calcareous sand, its engineering mechanical properties differ from ordinary terrestrial sand. Furthermore, the harsh natural environment and fragile ecosystem of island and reef areas present challenges in construction, including difficulties, environmental pollution, and cost control. Traditional foundation treatment methods such as vibro-compaction and cement grouting suffer from construction disturbance and environmental pollution. Additionally, construction costs are often high due to the need to transport all necessary engineering materials from land. Therefore, there is an urgent need for a new, eco-friendly island and reef reinforcement technology suitable for marine environments and calcareous sand sites. Microbial-induced calcium carbonate precipitation (MICP) reinforcement technology offers advantages over traditional cement grouting, such as lower grouting pressure, shorter curing time, natural raw material sources, and environmental friendliness, presenting new opportunities for green and environmentally friendly geotechnical island and reef engineering reinforcement technologies. However, MICP also has some drawbacks, such as the long-term issue of weak adhesion of calcium carbonate particles. Summary of the Invention

[0003] The purpose of this invention is to provide a method for island and reef reinforcement based on temperature-controlled MIP. By introducing the temperature-controlled MIP method into the protection engineering of large-scale island and reef reinforcement, the initial reinforcement of the island and reef can be achieved. At the same time, the method of xanthan gum consolidation and drying consolidation can be combined to achieve multiple cycles of reinforcement of the island and reef.

[0004] The technical solution to achieve the purpose of this invention is as follows: a reef reinforcement system based on temperature-controlled MICP, including a xanthan gum liquid tank, a constant-temperature storage tank, a bacterial liquid tank and a reaction liquid tank set in the constant-temperature storage tank, a constant-temperature storage tank, a mixed liquid tank set in the constant-temperature storage tank, a solar thermal energy storage device for maintaining the constant temperature of the constant-temperature storage tank, a peristaltic pump, a water injection pipe, a drain pipe, a drainage channel set between the water injection pipe and the drain pipe, a water collection tank and a vacuum pump, and the constant-temperature storage tank uses a groundwater extraction device to achieve a temperature of 4±0.5℃;

[0005] The various components are connected by valves and pipelines, which realizes the first reinforcement of the island and reef by injecting the mixed liquid at the required temperature into the area to be reinforced by the MICP, the second reinforcement by injecting xanthan gum solution, and the third reinforcement of the island and reef by pumping out the liquid in the area to be reinforced.

[0006] Furthermore, one end of the main pipeline of the principle water injection pipe is connected to the xanthan gum liquid tank via valve I;

[0007] The outlet of the bacterial culture tank and the outlet of the reaction liquid tank converge into one pipeline through valve III and then connect to the main pipeline through valve II. The mixing tank is equipped with valve V. The bacterial culture tank and the reaction liquid tank enter the mixing tank for mixing with the help of a peristaltic pump and valve.

[0008] A peristaltic pump and valve VI are installed sequentially between the mixing tank and the water injection pipe;

[0009] The outlet of the drain pipe is connected to the water collection tank via a pipeline and valve VII, and a vacuum pump is installed after the water collection tank.

[0010] Furthermore, the drainage channels are evenly distributed vertically in the area to be reinforced on the islands and reefs, so as to achieve uniform injection of mixed liquid or xanthan gum into the area to be reinforced.

[0011] A method for reinforcing islands and reefs using the aforementioned reinforcement system includes the following steps:

[0012] Step (1): Prepare high-yield urease-producing bacterial solution and reaction solution. Place the high-yield urease-producing bacterial solution and reaction solution in the bacterial solution tank and reaction solution tank respectively, and use extracted groundwater for cooling treatment.

[0013] Step (2): Using a solar thermal storage device, set the temperature of the mixing tank to 25°C, open valves II, III, IV and V, and pour the reaction liquid and high-yield urease bacteria liquid into the mixing tank under the action of a peristaltic pump;

[0014] Step (3): Open valves V, VI and VII. Under the action of the peristaltic pump, inject the bacterial mixed cementitious solution in the mixing tank into the island and reef to be reinforced through the injection pipe and the drainage channel; repeat until the island and reef to be reinforced is completely wetted, so as to realize the temperature-controlled MICP island and reef one-time reinforcement.

[0015] Step (4): Open valve I, valve VI and valve VII, and inject xanthan gum solution into the island reef to be reinforced under the action of peristaltic pump. Repeat until the island reef to be reinforced is completely wetted to achieve secondary reinforcement of the island reef.

[0016] Step (5): Open valves VI and VII, and under the action of the vacuum pump, extract the waste liquid and groundwater in the island and reef to be reinforced through the drainage pipe, and achieve the three-stage reinforcement of the island and reef through drying and consolidation.

[0017] Furthermore, the reaction solution in step (1) is a mixed solution of calcium chloride and urea, wherein the concentration of the calcium chloride solution is 2 mol / L, the concentration of the urea solution is 2 mol / L, and the concentration of the reaction solution after mixing equal volumes is 1 mol / L.

[0018] Furthermore, the concentration of the high-urease-producing bacterial solution was in a supersaturated state, and the activity was 2×10⁻⁶. 8cells / mL.

[0019] Furthermore, the specific steps for preparing the high-yield urease-producing bacterial culture in step (1) are as follows:

[0020] Step (11): Prepare the first culture medium: The first culture medium includes: seawater, peptone, yeast extract, sodium carbonate, sodium bicarbonate, agar powder and artificial urea; place the prepared first culture medium in an autoclave for high-temperature sterilization;

[0021] Step (12): Pour the sterilized first culture medium into a petri dish: Before the sterilized first culture medium containing agar powder cools and solidifies, pour the sterilized first culture medium into a petri dish to prepare a solid agar plate for bacterial activation.

[0022] Step (13): Bacterial activation: Take out the refrigerated high urease-producing bacterial strain and put it into seawater. Once the bacterial strain becomes liquid, a bacterial suspension can be obtained. Add the bacterial suspension to the solid agar plate prepared in step (12) and spread the added bacterial suspension evenly. Seal the petri dish and incubate at a constant temperature.

[0023] Step (14): Prepare the second culture medium: The second culture medium includes: seawater, peptone, yeast extract, sodium carbonate, sodium bicarbonate, and artificial urea; place the prepared second culture medium in an autoclave for high-temperature sterilization;

[0024] Step (15): Bacterial culture: Pick a single colony from step (13), inoculate it into the second culture medium, and culture it at a constant temperature to obtain a high-yield urease-producing bacterial solution.

[0025] Furthermore, in step (2), the reaction solution and bacterial solution are mixed in equal volumes and poured into the mixing tank at a rate of 100±10 ml / min.

[0026] Furthermore, in step (3), the bacterial mixed cementing solution is injected into the calcareous sand of the island reef area to be reinforced at a rate of 500±50L / h.

[0027] Furthermore, in step (4), the concentration of xanthan gum solution used is 100±10g / L, and it is injected into the calcareous sand of the island reef area to be reinforced at a rate of 10±1L / h.

[0028] Compared with the prior art, the significant advantages of this invention are:

[0029] (1) This invention applies the “temperature-controlled MIP method” to the construction of large island and reef reinforcement, solves the problem of slow urease metabolism under low temperature conditions, and improves the activity of urease bacteria and the solidification effect of MIP island and reef by temperature control, thereby greatly improving the reinforcement effect of island and reef.

[0030] (2) The present invention uses xanthan gum solution, which ensures that the bacterial solution, reaction solution and the island and reef to be reinforced are fully mixed before the MIP reaction occurs, so that the calcium carbonate generated by the MIP reaction will be more evenly distributed in the sand and soil, solving the problem of the calcium carbonate particles not being firmly bonded for a long time; at the same time, the addition of xanthan gum greatly improves the mechanical properties of the island and reef, and has a positive effect on the reinforcement of the island and reef.

[0031] (3) Tropical island and reef areas lack freshwater resources. This invention utilizes seawater resources to cultivate microorganisms, which will bring huge economic and environmental benefits.

[0032] (4) In view of the problems of inconvenient material sourcing and high transportation costs in the process of island and reef development, the island and reef resources and waste resources are fully utilized to realize the foundation processing method of local material sourcing and waste utilization. At the same time, since no chemical products such as cement are used, the reinforcement formed by biological methods is more environmentally friendly and has less impact on the environment. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the reinforcement system of the present invention.

[0034] Explanation of reference numerals in the attached figures:

[0035] 1-Valve I, 2-Valve II, 3-Valve III, 4-Valve IV, 5-Valve V, 6-Valve VI, 7-Valve VII, 8-Xanthan Gum Tank, 9-Bacterial Liquid Tank, 10-Reaction Liquid Tank, 11-Constant Low Temperature Storage Tank, 12-Groundwater Extraction Device, 13-Constant Temperature Storage Tank, 14-Solar Energy Storage Unit, 15-Mixed Liquid Tank, 16-Peristaltic Pump, 17-Water Injection Pipe, 18-Drainage Pipe, 19-Island / Reef Reinforcement Area, 20-Water Collection Tank, 21-Vacuum Pump. Detailed Implementation

[0036] The present invention will now be described in further detail with reference to the accompanying drawings.

[0037] like Figure 1 As shown, an island and reef reinforcement system based on temperature-controlled MICP includes a xanthan gum liquid tank 8, a constant-temperature storage tank 11, a bacterial liquid tank 9 and a reaction liquid tank 10 installed in the constant-temperature storage tank 11, a constant-temperature storage tank 13, a mixing liquid tank 15 installed in the constant-temperature storage tank 13, a solar thermal energy storage device for maintaining the constant temperature of the constant-temperature storage tank 13, a peristaltic pump 16, a water injection pipe 17, a drain pipe 18, a drainage channel installed between the water injection pipe 17 and the drain pipe 18, a water collection tank 20, and a vacuum pump 21. The constant-temperature storage tank 11 uses a groundwater extraction device 12 to achieve a temperature of 4±0.5℃.

[0038] The various components are connected by valves and pipelines to achieve the first reinforcement by injecting the mixed liquid at the required temperature into the island and reef reinforcement area 19, followed by the injection of xanthan gum to complete the second reinforcement, and finally the tertiary reinforcement by draining the liquid from the island and reef reinforcement area.

[0039] One end of the main pipeline away from the water injection pipe 17 is connected to the xanthan gum liquid tank 8 via valve I1;

[0040] The outlet of the bacterial culture tank 9 and the outlet of the reaction liquid tank 10 converge into a single pipeline via valve III and valve IV4, and are connected to the main pipeline via valve II2. The mixing tank 15 is equipped with valve V5. The bacterial culture tank 9 and the reaction liquid tank 10 enter the mixing tank 15 for mixing with the help of the peristaltic pump and the valve.

[0041] A peristaltic pump 16 and a valve VI6 are sequentially installed between the mixing tank 15 and the water injection pipe 17;

[0042] The outlet of the drain pipe 18 is connected to the water collection tank 20 through a pipeline and valve VII7, and a vacuum pump 21 is installed after the water collection tank 20.

[0043] The drainage channels are evenly distributed vertically in the island and reef reinforcement area 19 to achieve uniform injection of mixed liquid or xanthan gum liquid into the island and reef reinforcement area 19.

[0044] A method for island and reef reinforcement based on temperature-controlled MICP includes the following steps:

[0045] Step 1: Based on the low temperature conditions of groundwater, the pre-prepared reaction solution and the high-yield urease-producing bacterial solution are placed in the extracted groundwater for cooling treatment.

[0046] Step 2: Based on the utilization of solar energy resources, the mixing tank 15 is kept in a constant temperature environment of 25°C. Open the valve and peristaltic pump 16 to pour the reaction solution and bacterial solution into the mixing tank 15.

[0047] Step 3: Open the valve and peristaltic pump 16 to inject the mixture into the calcium sand layer at different depths in the area to be reinforced on the island and reef, so as to realize the one-time reinforcement of the island and reef by temperature-controlled microbial induced calcium carbonate precipitation (MICP).

[0048] Step 4: Open the valve and peristaltic pump 16 to inject xanthan gum solution into the calcium sand layer at different depths in the area to be reinforced on the island and reef, thereby achieving secondary reinforcement of the island and reef.

[0049] Step 5: Turn on vacuum pump 21 to extract waste liquid and groundwater from the area of ​​the island to be reinforced, and achieve the third reinforcement of the island through drying and consolidation.

[0050] Step one: Based on the low temperature conditions of groundwater, the pre-prepared reaction solution and the high-yield urease-producing bacterial solution are placed in the extracted groundwater for cooling treatment, specifically including the following:

[0051] (1-1): Preparation of the first culture medium: The first culture medium includes: seawater, peptone, yeast extract, sodium carbonate, sodium bicarbonate, agar powder and artificial urea; The prepared first culture medium is placed in an autoclave for high-temperature sterilization;

[0052] (1-2): Pour the sterilized first culture medium into a petri dish: Before the sterilized first culture medium containing agar powder cools and solidifies, pour the sterilized first culture medium into a petri dish to prepare a solid agar plate for bacterial activation.

[0053] (1-3): Bacterial activation: Take out the refrigerated high urease-producing bacterial strain and put it into seawater. Once the bacterial strain becomes liquid, a bacterial suspension can be obtained. Add the bacterial suspension to the solid agar plate prepared in step (12) and spread the added bacterial suspension evenly. Seal the petri dish and incubate at a constant temperature.

[0054] (1-4): Prepare the second culture medium: The second culture medium includes: seawater, peptone, yeast extract, sodium carbonate, sodium bicarbonate, and artificial urea; place the prepared second culture medium in an autoclave for high-temperature sterilization;

[0055] (1-5): Bacterial culture: Pick a single colony from step (13), inoculate it into the second culture medium, and incubate at constant temperature to obtain a high-yield urease-producing bacterial solution.

[0056] Step two: Based on the utilization of solar energy resources, the mixing tank is kept in a constant temperature environment of 25°C. The valve and peristaltic pump are opened to pour the reaction solution and bacterial solution into the mixing tank, specifically including the following:

[0057] (2-1): Open valves 2, 3, 4 and 5, mix equal volumes of reaction solution and bacterial solution and pour into the mixing tank at 100 ml / min to form bacterial mixture;

[0058] (2-2): Due to the harsh geographical environment of the islands and reefs, in order to save resources, concave mirrors are used to convert solar energy into thermal energy, so that the mixing tank is kept at a constant temperature of 25°C.

[0059] Step three involves opening the valves and peristaltic pump to inject the mixture into calcium sand layers at different depths in the area to be reinforced, achieving temperature-controlled microbial induced calcium carbonate precipitation (MICP) reinforcement of the island and reef in a single step. This includes the following:

[0060] (3-1): In the area to be reinforced, set up longitudinal injection ports and drainage ports;

[0061] (3-2): Burying injection pipes and drainage pipes: Install injection pipes in injection wells and drainage pipes in drainage wells. Open valves 5, 6, and 7 and the peristaltic pump. Add bacterial mixed cementitious liquid to the injection pipes and inject it into the calcareous sand of each layer of the island reef to be reinforced at a rate of 500L / h.

[0062] (3-3): Repeat (3-1)-(3-2) until the island / reef area to be reinforced is completely saturated, thus achieving one-time reinforcement of the island / reef by temperature-controlled microbial induced calcium carbonate precipitation (MICP).

[0063] Step four: Open the valves and peristaltic pump to inject xanthan gum solution into the calcium sand layer at different depths in the area to be reinforced on the island / reef, thereby achieving secondary reinforcement of the island / reef. This specifically includes the following:

[0064] Close valve 5, open valves 1, 6, and 7 and the peristaltic pump, add xanthan gum solution to the injection pipe, and inject it into the calcareous sand of each layer of the reef to be reinforced at a rate of 10 L / h; repeat 5-10 times until the area of ​​the reef to be reinforced is completely wetted, thus achieving secondary reinforcement of the reef.

[0065] Step five: Turn on the vacuum pump to extract waste liquid and groundwater from the area of ​​the island / reef to be reinforced, and achieve the three-stage reinforcement of the island / reef through drying and consolidation, specifically including the following:

[0066] Close valve 1 and the peristaltic pump, open valves 6 and 7 and the vacuum pump, and extract waste liquid and groundwater from the island and reef area to be reinforced through the drain pipe. The island and reef will be reinforced three times through drying and consolidation.

[0067] This invention utilizes temperature-controlled microbial MIP-induced treatment, where urease-inducing bacteria catalyze hydrolysis under the action of urease, thereby enhancing the precipitation efficiency of MIP and achieving microbial-induced calcium carbonate precipitation in the island / reef reinforcement area, thus achieving a primary reinforcement effect. Simultaneously, the addition of xanthan gum achieves a secondary reinforcement effect. Finally, a drying and consolidation method is used to drain the liquid from the island / reef reinforcement area, achieving a tertiary reinforcement effect. By repeating the above steps, multiple cycles of reinforcement can be achieved, significantly improving the reinforcement effect of the island / reef.

Claims

1. An island and reef reinforcement system based on temperature-controlled MICP, characterized in that, Includes xanthan gum liquid tank (8), constant temperature storage tank (11), bacterial liquid tank (9) and reaction liquid tank (10) set in constant temperature storage tank (11), constant temperature storage tank (13), mixed liquid tank (15) set in constant temperature storage tank (13), solar thermal energy storage device for maintaining constant temperature of constant temperature storage tank (13), peristaltic pump (16), water injection pipe (17), drain pipe (18), drainage channel set between water injection pipe (17) and drain pipe (18), water collection tank (20) and vacuum pump (21). The constant temperature storage tank (11) uses groundwater extraction device (12) to achieve a temperature of 4±0.5℃. The various components are connected by valves and pipelines to achieve the first reinforcement by injecting the mixture at the required temperature into the island reef to be reinforced area (19), the second reinforcement by injecting xanthan gum, and the third reinforcement by pumping out the liquid in the island reef to be reinforced area. One end of the main pipeline away from the water injection pipe (17) is connected to the xanthan gum liquid tank (8) through valve I (1); The outlet of the bacterial liquid tank (9) and the outlet of the reaction liquid tank (10) are connected to a pipeline through valve III and valve IV (4), and then connected to the main pipeline through valve II (2); the mixing tank (15) is equipped with valve V (5), and the bacterial liquid tank (9) and the reaction liquid tank (10) enter the mixing tank (15) to achieve mixing with the cooperation of the peristaltic pump and the valve; A peristaltic pump (16) and a valve VI (6) are sequentially installed between the mixing tank (15) and the water injection pipe (17); The outlet of the drain pipe (18) is connected to the water collection tank (20) through the pipeline and valve VII (7), and a vacuum pump (21) is installed after the water collection tank (20).

2. The reinforcement system according to claim 1, characterized in that, The drainage channels are evenly distributed vertically in the island and reef reinforcement area (19) to achieve uniform injection of mixed liquid or xanthan gum into the island and reef reinforcement area (19).

3. A method for reinforcing islands and reefs using the reinforcement system described in any one of claims 1-2, characterized in that, Includes the following steps: Step (1): Prepare high-yield urease-producing bacterial solution and reaction solution. Place the high-yield urease-producing bacterial solution and reaction solution in the bacterial solution tank (9) and reaction solution tank (10) respectively, and use extracted groundwater for cooling treatment. Step (2): Using a solar thermal storage device, set the temperature of the mixing tank to 25°C, open valves II, III, IV and V, and pour the reaction liquid and high-yield urease bacteria solution into the mixing tank (15) under the action of a peristaltic pump. Step (3): Open valves V, VI and VII. Under the action of the peristaltic pump, inject the bacterial mixed cementitious solution in the mixing tank into the island and reef to be reinforced through the water injection pipe (17) and the drainage channel; repeat until the island and reef to be reinforced is completely wetted, so as to realize the temperature-controlled MICP island and reef one-time reinforcement. Step (4): Open valve I, valve VI and valve VII, and inject xanthan gum solution into the area to be reinforced on the island and reef under the action of the peristaltic pump. Repeat until the area to be reinforced on the island and reef is completely wetted to achieve secondary reinforcement of the island and reef. Step (5): Open valves VI and VII, and under the action of the vacuum pump, extract the waste liquid and groundwater in the island and reef to be reinforced through the drainage pipe, and achieve the three-stage reinforcement of the island and reef through drying and consolidation.

4. The method according to claim 3, characterized in that, The reaction solution in step (1) is a mixture of calcium chloride and urea, wherein the concentration of the calcium chloride solution is 2 mol / L, the concentration of the urea solution is 2 mol / L, and the concentration of the reaction solution after mixing equal volumes is 1 mol / L.

5. The method according to claim 4, characterized in that, The concentration of the high-urease-producing bacteria in the bacterial solution was supersaturated, and the activity was 2 × 10⁻⁶. 8 cells / mL.

6. The method according to claim 5, characterized in that, The specific steps for preparing the high-yield urease-producing bacterial culture in step (1) are as follows: Step (11): Prepare the first culture medium: The first culture medium includes: seawater, peptone, yeast extract, sodium carbonate, sodium bicarbonate, agar powder and artificial urea; place the prepared first culture medium in an autoclave for high-temperature sterilization; Step (12): Pour the sterilized first culture medium into a petri dish: Before the sterilized first culture medium containing agar powder cools and solidifies, pour the sterilized first culture medium into a petri dish to prepare a solid agar plate for bacterial activation. Step (13): Bacterial activation: Take out the refrigerated high urease-producing bacterial strain and put it into seawater. Once the bacterial strain becomes liquid, a bacterial suspension can be obtained. Add the bacterial suspension to the solid agar plate prepared in step (12) and spread the added bacterial suspension evenly. Seal the petri dish and incubate at a constant temperature. Step (14): Prepare the second culture medium: The second culture medium includes: seawater, peptone, yeast extract, sodium carbonate, sodium bicarbonate, and artificial urea; place the prepared second culture medium in an autoclave for high-temperature sterilization; Step (15): Bacterial culture: Pick a single colony from step (13), inoculate it into the second culture medium, and culture it at a constant temperature to obtain a high-yield urease-producing bacterial solution.

7. The method according to claim 6, characterized in that, In step (2), the reaction solution and bacterial solution are mixed in equal volumes and poured into the mixing tank at a rate of 100±10 ml / min.

8. The method according to claim 7, characterized in that, In step (3), the bacterial mixed cementing solution is injected into the calcareous sand of the island and reef area to be reinforced at a rate of 500±50L / h.

9. The method according to claim 8, characterized in that, The concentration of xanthan gum solution used in step (4) is 100±10g / L, and it is injected into the calcareous sand of the island and reef area to be reinforced at a rate of 10±1L / h.

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