Self-filling high-strength earth-rock dam water blocking material and preparation method thereof

Abstract

The application discloses a self-filling high-strength earth-rock dam water-stopping material and a preparation method thereof, and particularly relates to the following steps: adding active bacteria granules and bentonite into earth-rock materials, mixing to obtain premix, adding a gelling agent, ball-milling and mixing to obtain aggregate particles; placing the aggregate particles on a stirrer and spraying an organic solution on the aggregate particles for hydrophobic modification to obtain modified aggregate, drying, and mixing with urea to obtain the self-filling high-strength earth-rock dam water-stopping material. The method utilizes the urease of bacteria and the microbial induced carbonate precipitation (MICP) reaction of urea to form calcium carbonate precipitation, fills the pore structure in traditional earth-rock materials, and reduces the porosity and pore size, so that the overall water permeability of the dam body can be improved, and the overall dam body is more compact due to the reduction of the porosity, and the strength is improved to improve the resistance to external water pressure.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of sealing material preparation, and particularly relates to a preparation method of self-filling high-strength earth and rock dam water sealing material and the self-filling high-strength earth and rock dam water sealing material. BACKGROUND

[0002] The earth and rock dam is a common water conservancy engineering structure, mainly used for water storage and flood control, and has the advantages of local material, saving of building materials and reduction of long-distance transportation during dam construction. The structural design of the earth and rock dam is simple, easy to maintain and heighten, and expand, and the dam body of the earth and rock dam is a soil and rock granular structure, which has good deformation adaptation performance. The mechanical properties of the earth and rock dam material have an important influence on the design and construction of the earth and rock dam, and the mechanical property requirements cover multiple aspects such as strength, stability and permeability of the material, so as to ensure that the earth and rock dam can remain stable and safe under various environmental conditions. The earth and rock dam is built by various methods, and the raw materials used are mainly stone, soil or mixed materials according to the selected raw materials. However, there is a certain gap between the particle materials of the two materials. When the reservoir is filled with water, due to the action of water pressure, water penetrates through the gap between the earth and rock particles to the downstream dam body and foundation, causing a certain amount of seepage. At the same time, low strength will lead to the inability to resist the impact of water pressure, thereby damaging the overall stability and affecting the safety of actual use.

[0003] Chinese patent (application number: 202310980931.1, publication number: CN117143448A, publication date: 2023.12.01) discloses a preparation method of a coal mine underground reinforcing water sealing material, which adopts the reaction of two-phase materials to form an interpenetrating network structure to fill pores, thereby achieving water sealing. However, there are still pores in the interpenetrating network and only physical filling cannot achieve effective drainage function. Therefore, it is an urgent problem to be solved in the field of engineering materials to modify and improve the current traditional earth and rock dam water sealing material formula and construct a green earth and rock dam water sealing material with good impermeability and high strength. SUMMARY

[0004] The purpose of the present application is to provide a preparation method of self-filling high-strength earth and rock dam water sealing material, which solves the problem that the existing earth and rock dam water sealing material cannot simultaneously consider high strength and water permeability resistance.

[0005] Another purpose of the present application is to provide a self-filling high-strength earth and rock dam water sealing material.

[0006] The technical scheme adopted by the present application is a preparation method of self-filling high-strength earth and rock dam water sealing material, which is specifically implemented according to the following steps:

[0007] Step 1, pre-preparing active bacteria particles;

[0008] Step 2, the active bacteria particles obtained in step 1 are added to the soil and rock materials, mixed to obtain a premix, and then a gelling agent is added and mixed by ball milling to obtain aggregate particles;

[0009] Step 3, the aggregate particles in step 2 are placed on a stirrer and stirred, and an organic solution is sprayed on the aggregate particles, i.e. hydrophobic modification is carried out, to obtain modified aggregate;

[0010] Step 4, the modified aggregate obtained in step 3 is dried, and then mixed and stirred with urea to obtain a self-filling high-strength soil and rock dam water-blocking material.

[0011] The application also has the characteristics that,

[0012] In step 1, specifically,

[0013] Step 1.1, protein peptone, sodium chloride, and yeast extract are mixed with water, sterilized by high temperature and high pressure, and a bacterial culture solution is formed, and the active bacteria are cultured with the bacterial culture solution to obtain a bacterial solution;

[0014] Step 1.2, agar powder is dissolved in water, stirred, sterilized, and dried under sterile conditions to obtain an agar plate; the bacterial solution obtained in step 1.1 is placed on the agar plate, sterilized, dried and solidified, and broken into powder to obtain active bacteria particles.

[0015] In step 1.1, the active bacteria are any one of exopolysaccharide-producing bacteria, urease-producing bacteria, denitrifying bacteria, sulfate-reducing bacteria, and methanotrophic bacteria.

[0016] In step 1.2, the dissolution temperature is 50-70 DEG C, and the stirring time is 3-5 h; when breaking, the rotation speed is 200-400 r / min, and the breaking time is 3-5 h.

[0017] In step 2, the mass ratio of active bacteria particles, bentonite, and soil and rock materials is 1:1:3; the mass ratio of gelling agent to premix is 1:3-5.

[0018] In step 2, the bentonite is calcium-based bentonite or sodium-based bentonite; the gelling agent is any one of an epoxy resin-based gelling agent, an acrylic acid-based gelling agent, a polyurethane-based gelling agent, and a synthetic rubber-based gelling agent.

[0019] In step 3, the organic solution is obtained by mixing a coupling agent and water;

[0020] The coupling agent is any one of a sulfur silane coupling agent, an amino silane coupling agent, and an epoxy-based silane coupling agent; the mass ratio of the organic solution to the aggregate particles is 5:1.

[0021] In step 4, the drying temperature is 100-150 DEG C, the drying time is 2-4h, and the stirring time is 3-5h; and the mass ratio of the modified aggregate to urea is 1:5-10.

[0022] Another technical solution of the application is that the self-filling high-strength earth-rock dam water-stopping material is prepared by the preparation method of the self-filling high-strength earth-rock dam water-stopping material.

[0023] The method has the advantages that: the method firstly utilizes the microorganism-induced calcium carbonate precipitation MICP reaction of bacteria, under the action of nutrients (urea), the urease of the bacteria can decompose urea to form calcium carbonate precipitation, thereby filling the pores between the aggregates to improve the water permeability resistance, and the reduction of the porosity improves the mechanical properties; the water-soluble organic gel agent is used as the shell of the aggregate, when the whole material meets water, the shell is dissolved in water, the bentonite in the core expands when meeting water, and the expansion force and the surface hydrophobic group are used to automatically discharge the water in the dam body, meanwhile, the bacteria dissolved in water react with urea to generate calcium carbonate precipitation to fill the drainage channel, which is beneficial to long-term use, and after the drainage is completed, the calcium carbonate connects the aggregates to effectively transmit the expansion force of the bentonite and generate prestress, thereby further improving the strength, and when the dam body is impacted by superhigh water pressure, the overall safety and stability of the dam body can be effectively improved. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The figure is a structural diagram of the self-filling high-strength earth-rock dam water-stopping material.

[0025] In the figure, 1 is an active bacteria particle, 2 is a stone, 3 is bentonite, and 4 is earth material. DETAILED DESCRIPTION

[0026] The application will be described in detail below in combination with the drawings and specific embodiments.

[0027] The preparation method of the self-filling high-strength earth-rock dam water-stopping material is specifically implemented according to the following steps.

[0028] Step 1, preparing an active bacteria particle; specifically,

[0029] Step 1.1, mixing protein peptone, sodium chloride and yeast extract with water to perform high-temperature and high-pressure sterilization to form a bacterial culture solution, and culturing the active bacteria with a volume ratio of 1:100 to the bacterial culture solution to obtain a bacterial solution;

[0030] The culturing time is 24h.

[0031] The active bacteria are any one of extracellular polymer-producing bacteria, urease-producing bacteria, denitrifying bacteria, sulfate-reducing bacteria and methane-oxidizing bacteria.

[0032] The mass ratio of peptone to water is 1:100; the mass ratio of sodium chloride to water is 1:200; and the mass ratio of yeast extract to water is 1:200;

[0033] Step 1.2, dissolving the agar powder in water, stirring, sterilizing, drying in a sterile state to obtain an agar plate; spreading the bacterial liquid obtained in step 1.1 on the agar plate, sterilizing, drying and solidifying, crushing into powder to obtain active bacteria granules;

[0034] The dissolving temperature is 50-70℃, and the stirring time is 3-5h;

[0035] The rotation speed during crushing is 200-400r / min, and the crushing time is 3-5h;

[0036] The content of the bacterial liquid inoculated on the agar plate is 100-300 microliters;

[0037] Step 2, preparing aggregate granules: adding the active bacteria granules obtained in step 1 and bentonite into the earth-rock material, mixing at 30-40℃ for 2-4h to obtain a premix, and then adding a gelling agent and ball-milling to obtain the aggregate granules;

[0038] The bentonite is specifically calcium-based bentonite or sodium-based bentonite;

[0039] The mass ratio of soil to stone in the earth-rock material is 1:1;

[0040] The mass ratio of the active bacteria granules, bentonite and earth-rock material is 1:1:3;

[0041] The mass ratio of the gelling agent to the premix is 1:3-5;

[0042] The gelling agent is any one of an epoxy resin-based gelling agent, an acrylic acid-based gelling agent, a polyurethane-based gelling agent, and a synthetic rubber-based gelling agent;

[0043] The ball-milling rotation speed is 300-500r / min, and the ball-milling time is 3-5h;

[0044] Step 3, placing the aggregate granules in step 2 on a stirrer and spraying an organic solution on the aggregate granules, i.e. performing hydrophobic modification, to obtain modified aggregate;

[0045] The organic solution is mixed from a coupling agent and water; the concentration of the organic solvent is 0.5-1%;

[0046] The coupling agent is any one of a sulfur silane coupling agent, an amino silane coupling agent, and an epoxy-based silane coupling agent;

[0047] The mass ratio of the organic solution to the aggregate granules is 5:1;

[0048] The stirring speed is 200-400 r / min, and the stirring time is 10-30 min;

[0049] Step 4: Dry the modified aggregate obtained in Step 3, and then mix it with urea to obtain a self-filling high-strength earth-rock dam water-blocking material.

[0050] The drying temperature is 100-150℃, the drying time is 2-4 hours, and the stirring time is 3-5 hours.

[0051] The mass ratio of modified aggregate to urea is 1:5-10.

[0052] like Figure 1 The diagram shown is a structural diagram of the self-filling high-strength earth-rock dam water-blocking material prepared by the method of the present invention. A single circle represents modified aggregate particles, which are prepared by active bacterial particles 1, stone 2, bentonite 3 and soil 4 according to the steps.

[0053] The method of this invention utilizes the microbial induced calcium carbonate precipitation (MICP) reaction between bacteria's own urease and urea to form calcium carbonate precipitate, filling the pore structure in traditional soil and rock materials. The reduction in porosity and pore size can improve the overall seepage resistance of the dam body. At the same time, the decrease in porosity makes the overall dam body more compact, and the increased strength enhances its ability to resist external water pressure. In addition, a water-soluble organic solvent is used as a shell to pre-encapsulate bacteria and bentonite in the core. When encountering water that has seeped into the dam body, the outer shell pre-dissolves in water, releasing the core material. The bentonite swells upon contact with water, and due to the hydrophobic modification of the shell surface, the swelling force and surface hydrophobic groups help to expel water from the dam body. The bacteria dissolve and react with urea dissolved in water to generate calcium carbonate precipitate, filling the spaces where water has been expelled, further densifying the dam. Calcium carbonate also acts as a connector between the aggregates, effectively transferring the swelling force generated by the bentonite, achieving prestressing in the whole structure, further enhancing strength. When subjected to ultra-high water pressure, this effectively improves the overall safety and stability of the dam body.

[0054] Example 1

[0055] The preparation method of the self-filling high-strength earth-rock dam water-blocking material of the present invention is as follows:

[0056] Dissolve 5g peptone, 2.5g sodium chloride, and 2.5g yeast extract in 500ml water to form a bacterial culture medium. After high temperature and high pressure sterilization, incubate the extracellular polymeric bacteria with the bacterial culture medium at a ratio of 1:100 for 24 hours to obtain bacterial suspension. Add 10g agar powder to 500ml water at 50℃ and stir to dissolve for 3 hours. After sterilization and drying under aseptic conditions, take 100µL of bacterial suspension and spread it on top. After solidification, crush it at 200r / min for 3 hours to obtain active bacterial particles.

[0057] The traditional earth-rock dam material is adopted, wherein the mass ratio of soil material to stone material is 1:1; the mass ratio of active bacteria species granules, bentonite and earth-rock material is 1:1:3; the premix is mixed under dry condition at 30 DEG C for 2h; then the premix is added into the epoxy resin type gelling agent, and the mass ratio of gelling agent to premix is 1:3; the ball milling mixing is carried out at 300 r / min for 3h.

[0058] The sulfur silane coupling agent is configured into 0.5% concentration aqueous solution, the above-mentioned aggregate granules are placed on the stirrer, the proportion of aqueous solution to aggregate granules is adjusted to 5:1, the rotating speed is 200 r / min, the silane solution is sprayed on the aggregate granules and stirred for 10 minutes.

[0059] The modified aggregate obtained above is dried at 100 DEG C for 2h, and then is fully mixed with urea at room temperature for 3h, the urea content is 5 times of the active bacteria species bacterial liquid; then the modified aggregate is filled in the application field to form a dam body according to the traditional compaction method.

[0060] Example 2

[0061] The application discloses a preparation method of a self-filling high-strength earth-rock dam water-stopping material.

[0062] 500ml water is used to dissolve 5g peptone, 2.5g sodium chloride and 2.5g yeast extract to form a bacterial culture solution; after high-temperature and high-pressure sterilization, the extracellular polymer-producing bacteria are cultured in the bacterial culture solution at a ratio of 1:100 for 24h to obtain a bacterial liquid; 10g agar powder is added into 60 DEG C, 500ml water, stirred and dissolved for 3.5h, sterilized, dried in a sterile state, 150 microliters of the bacterial liquid is laid on the agar powder, broken at 250 r / min for 3.5h after solidification, and then active bacteria species granules are obtained.

[0063] The traditional earth-rock dam material is adopted, wherein the mass ratio of soil material to stone material is 1:1; the mass ratio of active bacteria species granules, bentonite and earth-rock material is 1:1:3; the premix is mixed under dry condition at 30 DEG C for 2.5h; then the premix is added into the epoxy resin type gelling agent, and the mass ratio of gelling agent to premix is 1:3; the ball milling mixing is carried out at 350 r / min for 3.5h.

[0064] The sulfur silane coupling agent is configured into 0.6% concentration aqueous solution, the above-mentioned aggregate granules are placed on the stirrer, the proportion of aqueous solution to aggregate granules is adjusted to 5:1, the rotating speed is 250 r / min, the silane solution is sprayed on the aggregate granules and stirred for 15 minutes.

[0065] The modified aggregate obtained above is dried at 110 DEG C for 2.5h, and then is fully mixed with urea at room temperature for 3.5h, the urea content is 6 times of the active bacteria species bacterial liquid; then the modified aggregate is filled in the application field to form a dam body according to the traditional compaction method.

[0066] Example 3

[0067] The application discloses a preparation method of a self-filling high-strength earth-rock dam water-stopping material.

[0068] 500ml water is dissolved with 5g proteose peptone, 2.5g sodium chloride and 2.5g yeast extract to form a bacterial culture solution, and after high-temperature and high-pressure sterilization, the urease-producing bacteria are cultured with the bacterial culture solution at a ratio of 1:100 for 24 hours to obtain a bacterial solution. 10g agar powder is added to 500ml water at 65 DEG C and stirred and dissolved for 4 hours, and after sterilization, the agar powder is dried in a sterile state, 200 microliters of the bacterial solution is laid on the agar powder, and after solidification, the agar powder is broken at 300r / min for 4 hours to obtain active bacteria granules.

[0069] The traditional earth-rock dam material is used, wherein the ratio of soil material to stone material is 1:1; the ratio of the active bacteria granules, bentonite and earth-rock material is 1:1:3; the premix is added into an acrylic gelling agent under dry conditions at a temperature of 35 DEG C for 3 hours, and the mass ratio of the gelling agent to the premix is 1:4; and the ball milling is carried out at 400r / min for 4 hours.

[0070] The sulfur silane coupling agent is configured into a water solution with a concentration of 0.75%, the aggregate particles are placed on a stirrer, the ratio of the water solution to the aggregate particles is adjusted to be 5:1, the rotating speed is 300r / min, the aggregate particles are sprayed with the silane solution and stirred for 20 minutes.

[0071] The modified aggregate particles obtained are dried at 130 DEG C for 3 hours, and the urea is fully mixed with the active bacteria solution at room temperature for 4 hours, the content of the urea is 8 times that of the active bacteria solution, and then the modified aggregate particles and the urea are filled into an application site to form a dam body in a traditional compaction method.

[0072] Example 4

[0073] The application discloses a preparation method of a self-filling high-strength earth-rock dam water-stopping material.

[0074] 500ml water is dissolved with 5g proteose peptone, 2.5g sodium chloride and 2.5g yeast extract to form a bacterial culture solution, and after high-temperature and high-pressure sterilization, the urease-producing bacteria are cultured with the bacterial culture solution at a ratio of 1:100 for 24 hours to obtain a bacterial solution. 10g agar powder is added to 500ml water at 65 DEG C and stirred and dissolved for 4 hours, and after sterilization, the agar powder is dried in a sterile state, 200 microliters of the bacterial solution is laid on the agar powder, and after solidification, the agar powder is broken at 300r / min for 4 hours to obtain active bacteria granules.

[0075] The traditional earth and rock dam material is used, wherein the ratio of soil material to rock material is 1:1; the ratio of active bacteria granules, bentonite and earth and rock material is 1:1:3; the premix is mixed under dry conditions at a temperature of 40 DEG C for 4 hours; then the premix is added to the acrylic acid gelling agent, and the mass ratio of the gelling agent to the premix is 1:5; the ball milling mixing is carried out at 500 r / min for 5 hours.

[0076] The sulfur silane coupling agent is configured into a 1% concentration aqueous solution; the aggregate particles are placed on a stirrer; the ratio of the aqueous solution to the aggregate particles is adjusted to be 5:1; the rotating speed is 400 r / min; the aggregate particles are sprayed with the silane solution and stirred for 30 minutes.

[0077] The modified aggregate obtained above is dried at 150 DEG C for 4 hours, and then mixed with urea at room temperature for 5 hours; the urea content is 10 times that of the active bacteria liquid; then the modified aggregate is filled in the dam body according to the traditional compaction method.

[0078] Table 1 is a comparison of the impermeability and compaction degree of the earth and rock dam of Examples 1-4 with the traditional earth and rock dam

[0079]

[0080] As shown in Table 1, the dam body is pre-formed with a certain prestress to resist the impact of external water pressure by using the swelling property of bentonite, and the pores are filled with calcium carbonate precipitates generated by the MICP reaction of specific bacteria, so that the impermeability and strength of the dam body are further improved after the compaction degree is improved, and the safety and stability of the dam body are improved.

Claims

1. A method for preparing self-filling high-strength earth-rock dam water-blocking material, characterized in that, The specific steps are as follows: Step 1, Pre-preparing active microbial granules; specifically: Step 1.1: Mix peptone, sodium chloride, yeast extract and water, and sterilize under high temperature and high pressure to form a bacterial culture medium. Incubate the active bacteria with the bacterial culture medium to obtain bacterial culture solution. Step 1.2: Dissolve agar powder in water, stir, sterilize, and dry under sterile conditions to obtain an agar plate; spread the bacterial solution obtained in Step 1.1 onto the agar plate, sterilize, dry and solidify, and break it into powder to obtain active bacterial granules. Step 2: Add the active bacterial granules obtained in Step 1 and bentonite to the soil and stone materials, mix them to obtain a premix, then add a gelling agent, ball mill and mix to obtain aggregate particles; The bentonite is either calcium-based bentonite or sodium-based bentonite; the gelling agent is any one of epoxy resin gelling agents, acrylic gelling agents, polyurethane gelling agents, or synthetic rubber gelling agents. Step 3: Place the aggregate particles from Step 2 on a mixer and stir, then spray an organic solution onto the aggregate particles to perform hydrophobic modification and obtain modified aggregate. The organic solution is a mixture of a coupling agent and water; the coupling agent is any one of sulfosilane coupling agents, aminosilane coupling agents, or epoxysilane coupling agents; the mass ratio of the organic solution to the aggregate particles is 5:

1. Step 4: Dry the modified aggregate obtained in Step 3, and then mix it with urea to obtain a self-filling high-strength earth-rock dam water-blocking material.

2. The preparation method of the self-filling high-strength earth-rock dam water-blocking material as described in claim 1, characterized in that, In step 1.1, the active bacterial strain is any one of the following: extracellular polymeric bacteria, urease-producing bacteria, denitrifying bacteria, sulfate-reducing bacteria, and methanogenic bacteria.

3. The preparation method of the self-filling high-strength earth-rock dam water-blocking material as described in claim 1, characterized in that, In step 1.2, the dissolution temperature is 50-70℃ and the stirring time is 3-5h; during crushing, the rotation speed is 200-400r / min and the crushing time is 3-5h.

4. The preparation method of the self-filling high-strength earth-rock dam water-blocking material as described in claim 1, characterized in that, In step 2, the mass ratio of active microbial granules, bentonite, and soil / stone is 1:1:3; the mass ratio of gelling agent to premix is ​​1:3-5.

5. The preparation method of the self-filling high-strength earth-rock dam water-blocking material as described in claim 1, characterized in that, In step 4, the drying temperature is 100-150℃, the drying time is 2-4h, the stirring time is 3-5h, and the mass ratio of modified aggregate to urea is 1:5-10.

6. The earth-rock dam water-blocking material prepared by the method for preparing self-filling high-strength earth-rock dam water-blocking material as described in any one of claims 1-5.

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