Water plugging and heat insulation grouting material suitable for high-temperature fissure rock mass and preparation method thereof

Abstract

The present application relates to the technical field of grouting material, and particularly relates to a water plugging and heat insulation grouting material suitable for high-temperature fissure rock mass and a preparation method, and the present application prepares a grouting material with water plugging and heat insulation effects. Compared with ordinary water commonly used in grouting materials, the introduction of micro-nano bubble water improves the heat insulation performance of the grouting material. The micro-nano bubble water is a closed bubble structure, and the introduction of the micro-nano bubble water improves the heat insulation performance of the grouting material. SiO2 aerogel in the grouting material is a kind of efficient heat insulation material, and has a very low thermal conductivity and a high porosity, which makes the material effectively prevent heat transfer in a high-temperature environment. The grouting material of the present application is not only suitable for water control engineering of high-temperature fissure rock mass, but also can provide effective heat insulation protection for the rock mass and the surrounding underground structure, and reduce the influence of the high-temperature environment on the safety of the structure. Thus, the problem of poor applicability of the existing grouting material in a high-temperature environment is solved.

Description

Technical Field

[0001] This invention relates to the field of grouting materials technology, and in particular to water-blocking and heat-insulating grouting materials and preparation methods adapted to high-temperature fractured rock masses. Background Technology

[0002] As transportation infrastructure development extends into geologically complex mountainous areas, tunnel engineering is trending towards deeper and longer tunnels, often requiring passage through more complex geological units. High ground temperature is one of the typical adverse geological problems in recent years. During the construction of high-temperature tunnels, construction along the tunnel route often faces complex groundwater networks. The influx of geothermal water significantly increases the hot and humid environment inside the tunnel, creating greater construction difficulties. Grouting has become a primary technical means for water plugging and reinforcement in underground engineering due to its high economic efficiency and simple construction techniques. For high-temperature, water-rich, fractured rock tunnels, grouting not only serves to plug water and reinforce the tunnel but also isolates heat sources and reduces the temperature inside the tunnel. In the actual construction of high-temperature tunnels, advanced curtain grouting can be used to isolate underground hot water and improve the high-temperature and high-humidity thermal environment inside the tunnel.

[0003] Currently, cement or cement-water glass grouting materials are commonly used in engineering projects for water plugging. However, these materials have poor applicability and effectiveness in high-temperature environments. In fact, ordinary cement-based grouting materials exhibit high water separation rates, long setting times, weak erosion resistance, and reduced strength of the cementitious aggregate under high-temperature conditions, making them unable to withstand the erosion of hot water and prone to secondary seepage. To achieve effective water plugging in tunnel construction, the amount of cement-based grout is often increased several times over, significantly reducing the economic efficiency of grouting measures. Cement-water glass grout has a shortened gelation time in geothermal environments, reducing the grout diffusion radius and making it difficult to form a sufficient curtain grouting layer. Furthermore, pipe blockage is prone to occur during grouting, hindering effective reinforcement of the strata. In addition, the aforementioned cement or cement-water glass grouting materials do not possess good thermal insulation properties; heat from geothermal water can still be transferred to the tunnel through the curtain grouting ring, resulting in a harsh tunnel environment and posing a greater challenge to the development of tunnel cooling measures.

[0004] To address the problems existing in current tunnel grouting materials, it is necessary to develop a new type of tunnel grouting material and preparation method that is suitable for high geothermal environments and combines water-blocking reinforcement with heat insulation. This material can not only ensure the safety requirements of tunnel construction, but also meet the heat insulation requirements of the tunnel interior environment throughout its entire life cycle, saving economic investment. This is a topic with significant theoretical and practical engineering value. Summary of the Invention

[0005] The purpose of this invention is to provide a water-blocking and heat-insulating grouting material and its preparation method that are suitable for high-temperature fractured rock masses, aiming to solve the problem of poor applicability of existing grouting materials in high-temperature environments.

[0006] To achieve the above objectives, in a first aspect, the present invention provides a method for preparing a water-blocking and heat-insulating grouting material adapted to high-temperature fractured rock masses, comprising the following steps:

[0007] Weigh out cement, biochar, rice husk ash, SiO2 aerogel, silica fume, retarder, stabilizer, water-reducing agent, and micro / nano bubble water according to the preset mass fraction;

[0008] Cement, biochar, rice husk ash, SiO2 aerogel, and silica fume are placed in a cement paste mixer and slowly mixed for 120 seconds to obtain a mixture.

[0009] The retarder, stabilizer, and water-reducing agent are added to the micro-nano bubble water and mixed and stirred to obtain a micro-nano bubble aqueous solution;

[0010] The micro-nano bubble aqueous solution and the mixture were added to a mixing pot and stirred slowly for 60 seconds and then stirred rapidly for 60 seconds to obtain a mixed grouting slurry material.

[0011] The mixed grouting slurry material was placed in a 60°C hot water bath and heated at a constant temperature before its thermophysical and mechanical properties were tested.

[0012] After testing, the mixed grouting slurry material was cast into a mold and then placed in a curing chamber for curing to obtain a high-temperature environment water-blocking grouting material.

[0013] In the step of "weighing cement, biochar, rice husk ash, SiO2 aerogel, silica fume, retarder, stabilizer, water-reducing agent, and micro / nano bubble water according to preset mass fractions," the mass fraction of cement is 30-70%; the mass fraction of biochar is 1-5%; the mass fraction of rice husk is 3-8%; the mass fraction of SiO2 aerogel is 15-30%; the mass fraction of silica fume is 2-6%; the mass fraction of retarder is 0.5-5%; the mass fraction of stabilizer is 0.2-1.5%; the mass fraction of water-reducing agent is 0.2-1.5%; and the mass fraction of micro / nano bubble water is 45%.

[0014] In the process of “weighing cement, biochar, rice husk ash, SiO2 aerogel, silica fume, retarder, stabilizer, water-reducing agent, and micro / nano bubble water according to a preset mass fraction,” the cement is ordinary silicate cement with a strength grade of not less than 42.5 MPa; the biochar is made by pyrolysis of wheat straw in a partially anaerobic environment; the rice husk ash is prepared by low-temperature combustion of rice husks; the SiO2 aerogel is nano aerogel powder; the silica fume is fine silica fume; the retarder is boric acid or sodium fluorosilicate, or calcium lignosulfonate; the stabilizer is any one of cellulose ether, polyvinyl alcohol, or water-soluble starch; the water-reducing agent is naphthalene-based, polycarboxylic acid-based, melamine-based, or lignin-based water-reducing agent; and the micro / nano bubble water is a non-chemical liquid medium with nano-sized bubbles.

[0015] Specifically, in the step of "weighing cement, biochar, rice husk ash, SiO2 aerogel, silica fume, retarder, stabilizer, water-reducing agent, and micro / nano bubble water according to a preset mass fraction," the biochar has a particle size ≤100 mesh; the SiO2 aerogel has a thermal conductivity of 0.013-0.020 W / (m·K), a particle size ≤3 mm, a pore size of 20-40 nm, and a porosity >90%; and the silica fume has an average particle size of 0.1-0.3 μm and a density of 2.33 g / cm³. 3 Its specific surface area is 20.5 m². 2 •kg; the micro-nano bubble water has a bubble diameter of 10-200nm and a bubble concentration of 10. 8 -10 9 per ml.

[0016] The step of "placing cement, biochar, rice husk ash, SiO2 aerogel, and silica fume into a cement paste mixer and slowly mixing for 120 seconds to obtain a mixture" includes the following steps:

[0017] Cement, biochar, rice husk ash, SiO2 aerogel, and silica fume are placed into the mixer in sequence;

[0018] Set the mixer to slow speed mode and mix for 120 seconds;

[0019] After mixing is complete, turn off the mixer and use a scraper to remove the mixture from the mixer and place it in a clean container for later use.

[0020] The step of "mixing and stirring the retarder, stabilizer, and water-reducing agent in micro-nano bubble water to obtain a micro-nano bubble aqueous solution" includes the following steps:

[0021] Add the weighed retarder, stabilizer, and water-reducing agent to the container containing micro-nano bubble water in sequence;

[0022] After setting the stirring speed of the electric mixer, mix the materials in the container.

[0023] Remove the micro-nano bubble aqueous solution from the container for later use.

[0024] The step of "adding the micro-nano bubble aqueous solution and mixture into a mixing pot and stirring slowly for 60 seconds and then rapidly for 60 seconds to obtain a mixed grouting slurry material" includes the following steps:

[0025] The prepared mixture and the micro / nano bubble aqueous solution were added separately into the mixing vessel;

[0026] Set the mixing bowl to the slow mixing mode and mix for 60 seconds.

[0027] Set the mixing bowl to the rapid mixing mode and mix for 60 seconds.

[0028] After mixing is complete, close the mixing pot and use a scraper to remove the mixed grouting material from the mixing pot and place it in a container for later use.

[0029] The step of "casting the tested mixed grouting slurry material into a mold and then curing it in a curing chamber to obtain a high-temperature environment water-blocking grouting material" includes the following steps:

[0030] The tested mixed grouting slurry material was poured into a 40×40×160mm mold. After molding, the mold was removed 24 hours later to obtain a semi-finished product.

[0031] The semi-finished product is placed in a cement mortar rapid curing box at 60℃ for a standard 28-day curing period to obtain a high-temperature environment water-blocking grouting material.

[0032] Secondly, the water-blocking and heat-insulating grouting material adapted to high-temperature fractured rock masses adopts the preparation method of the water-blocking and heat-insulating grouting material adapted to high-temperature fractured rock masses described in the first aspect, including cement, biochar, rice husk ash, SiO2 aerogel, silica fume, retarder, stabilizer, water-reducing agent and micro-nano bubble water.

[0033] The present invention discloses a method for preparing a water-blocking and heat-insulating grouting material adapted to high-temperature fractured rock masses, comprising the following steps: weighing cement, biochar, rice husk ash, SiO2 aerogel, silica fume, retarder, stabilizer, water-reducing agent, and micro-nano bubble water according to a preset mass fraction; slowly stirring the cement, biochar, rice husk ash, SiO2 aerogel, and silica fume in a cement paste mixer for 120 seconds to obtain a mixture; mixing the retarder, stabilizer, and water-reducing agent in the micro-nano bubble water to obtain a micro-nano bubble aqueous solution; adding the micro-nano bubble aqueous solution and the mixture to a mixing pot for 60 seconds of slow stirring and 60 seconds of rapid stirring to obtain a mixed grouting slurry material; heating the mixed grouting slurry material in a 60°C hot water bath using a magnetic stirring water bath and then conducting thermophysical and mechanical property tests; casting the tested mixed grouting slurry material into a mold and then curing it in a curing box to obtain a high-temperature environment water-blocking grouting material. The present invention prepares a grouting material with both water-blocking and heat-insulating effects. Compared to ordinary water commonly used in grouting materials, the introduction of micro-nano bubble water, with its closed bubble structure, improves the thermal insulation performance of the grouting material. SiO2 aerogel in the grouting material, as a highly efficient thermal insulation material, possesses extremely low thermal conductivity and high porosity, enabling it to effectively prevent heat transfer in high-temperature environments. The grouting material of this invention is not only suitable for water control projects in high-temperature fractured rock masses, but also provides effective thermal insulation protection for the rock mass and surrounding underground structures, reducing the impact of high-temperature environments on structural safety, thus solving the problem of poor applicability of existing grouting materials in high-temperature environments. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a flowchart of the preparation method of water-blocking and heat-insulating grouting material adapted to high-temperature fractured rock masses provided by the present invention.

[0036] Figure 2 The flowchart describes the process of slowly mixing cement, biochar, rice husk ash, SiO2 aerogel, and silica fume in a cement paste mixer for 120 seconds to obtain a mixture.

[0037] Figure 3 The flowchart describes the process of mixing and stirring retarder, stabilizer, and water-reducing agent in micro-nano bubble water to obtain a micro-nano bubble aqueous solution.

[0038] Figure 4The flowchart describes the process of adding the micro-nano bubble aqueous solution and the mixture into a mixing pot and stirring slowly for 60 seconds and then rapidly for 60 seconds to obtain a mixed grouting slurry material.

[0039] Figure 5 This is a flowchart illustrating the process of casting the tested mixed grouting slurry material into a mold and then curing it in a curing chamber to obtain a high-temperature environment water-blocking grouting material. Detailed Implementation

[0040] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0041] Please see Figures 1 to 5 In a first aspect, the present invention provides a method for preparing a water-blocking and heat-insulating grouting material adapted to high-temperature fractured rock masses, comprising the following steps:

[0042] S1 weighs cement, biochar, rice husk ash, SiO2 aerogel, silica fume, retarder, stabilizer, water-reducing agent, and micro-nano bubble water according to the preset mass fraction.

[0043] The cement content is 30-70% by mass; the biochar content is 1-5% by mass; the rice husk content is 3-8% by mass; the SiO2 aerogel content is 15-30% by mass; the silica fume content is 2-6% by mass; the retarder content is 0.5-5% by mass; the stabilizer content is 0.2-1.5% by mass; the water-reducing agent content is 0.2-1.5% by mass; and the micro / nano bubble water content is 45% by mass.

[0044] The cement is ordinary Portland cement with a strength grade of not less than 42.5 MPa; the biochar is made by pyrolysis of wheat straw in a partially anaerobic environment; the rice husk ash is prepared by low-temperature combustion of rice husks; the SiO2 aerogel is nano-aerogel powder; the silica fume is fine silica fume; the retarder is boric acid or sodium fluorosilicate, calcium lignosulfonate; the stabilizer is any one of cellulose ether, polyvinyl alcohol or water-soluble starch; the water-reducing agent is naphthalene-based, polycarboxylic acid-based, melamine-based, or lignin-based water-reducing agent; the micro-nano bubble water is a non-chemical liquid medium with nano-sized bubbles.

[0045] The biochar has a particle size ≤100 mesh; the SiO2 aerogel has a thermal conductivity of 0.013-0.020 W / (m·K), a particle size ≤3 mm, a pore size of 20-40 nm, and a porosity >90%; the silica fume has an average particle size of 0.1-0.3 μm and a density of 2.33 g / cm³. 3 Its specific surface area is 20.5 m². 2 •kg; the micro-nano bubble water has a bubble diameter of 10-200nm and a bubble concentration of 10. 8 -10 9 per ml.

[0046] Specifically, using an electronic scale, weigh each of the following components according to the preset mass fraction: cement, biochar, rice husk ash, SiO2 aerogel, silica fume, retarder, stabilizer, water-reducing agent, and micro-nano bubble water, ensuring accurate weighing. Place the weighed raw materials into clean containers and label them to prevent confusion.

[0047] S2: Cement, biochar, rice husk ash, SiO2 aerogel, and silica fume are placed in a cement paste mixer and slowly mixed for 120 seconds to obtain a mixture.

[0048] S21 puts cement, biochar, rice husk ash, SiO2 aerogel, and silica fume into the mixer in sequence;

[0049] Specifically, open the lid of the cement paste mixer and add cement, biochar, rice husk ash, SiO2 aerogel, and silica fume into the mixer in sequence.

[0050] S22 sets the mixer to slow mixing mode and mixes for 120 seconds;

[0051] Specifically, set the mixer to slow mixing mode, controlling the mixing speed within an appropriate range to avoid material splashing and mixer overload. Set the mixing time to 120 seconds to ensure the materials are thoroughly and evenly mixed. Observe the mixer's operating status and the uniformity of the mixture during the mixing process.

[0052] After S23 is finished mixing, turn off the mixer and use a scraper to remove the mixture from the mixer and place it in a clean container for later use.

[0053] Specifically, after mixing is complete, turn off the mixer and wait for it to stop completely before opening the lid. Use a spatula or shovel to remove the mixture from the mixer and place it in a clean container for later use.

[0054] S3 involves mixing and stirring a retarder, stabilizer, and water-reducing agent in micro-nano bubble water to obtain a micro-nano bubble aqueous solution.

[0055] S31 adds the weighed retarder, stabilizer and water-reducing agent to the container containing micro-nano bubble water in sequence;

[0056] Specifically, the weighed retarder, stabilizer, and water-reducing agent are added sequentially to the container containing micro-nano bubble water.

[0057] S32 sets the stirring speed of the electric stirrer to mix the materials in the container;

[0058] Specifically, use an electric or magnetic stirrer to mix the materials in the container. The stirring speed should be moderate to avoid generating too many bubbles or damaging the structure of the micro- and nano-bubbles. The stirring time depends on the specific situation, until all components are completely dissolved and evenly distributed in the micro- and nano-bubble water.

[0059] S33 removes the micro-nano bubble aqueous solution from the container for later use.

[0060] Specifically, after stirring is complete, turn off the stirrer and wait for it to stop completely before taking out the micro-nano bubble aqueous solution from the container for later use.

[0061] S4. The micro-nano bubble aqueous solution and the mixture are added to a mixing pot and stirred slowly for 60 seconds and then stirred rapidly for 60 seconds to obtain a mixed grouting slurry material.

[0062] S41. The prepared mixture and the micro / nano bubble aqueous solution are added separately into the mixing vessel;

[0063] Specifically, the prepared mixture and the micro / nano bubble aqueous solution are added separately to the mixing vessel.

[0064] S42 sets the mixing bowl to slow mixing mode and performs slow mixing for 60 seconds.

[0065] Specifically, set the mixing bowl to the slow mixing mode and mix for 60 seconds. The mixing speed should be moderate to ensure that the ingredients are thoroughly and evenly mixed.

[0066] S43 sets the mixing bowl to the rapid mixing mode for 60 seconds of rapid mixing;

[0067] Specifically, the mixing bowl is then set to rapid mixing mode for 60 seconds. Rapid mixing helps improve the uniformity and fluidity of the grouting material, providing favorable conditions for subsequent construction and curing.

[0068] After S44 mixing is completed, the mixing pot is closed, and the mixed grouting slurry material is removed from the mixing pot using a scraper and placed in a container for later use.

[0069] Specifically, after mixing is complete, the mixing pot is turned off and waited for it to stop completely. Then, the mixed grouting slurry material is removed from the mixing pot by a scraper and placed in a container for later use.

[0070] S5 uses a magnetically stirred water bath to place the mixed grouting material in a 60°C hot water bath for constant temperature heating and then conducts thermophysical and mechanical property tests.

[0071] Specifically, the temperature of the magnetically stirred water bath is set to 60℃, and the mixed grouting slurry material is placed in the water bath for constant-temperature heating. During heating, a magnetic stirrer is used to ensure uniform heating of the slurry. Thermophysical and mechanical properties of the mixed grouting slurry material are tested periodically during the heating process. Test items include, but are not limited to, compressive strength, impermeability, and thermal insulation performance. Test data are recorded for subsequent analysis and evaluation of the grouting material's performance.

[0072] S6 casts the tested mixed grouting material into a mold and then places it in a curing chamber for curing to obtain a high-temperature environment water-blocking grouting material.

[0073] S61 pours the tested mixed grouting material into a 40×40×160mm mold, and removes the mold after 24 hours to obtain a semi-finished product;

[0074] Specifically, select a suitable mold (e.g., a 40×40×160mm mold) and pour the tested mixed grouting material into the mold. Use a scraper or shovel to smooth the grouting material inside the mold to ensure even distribution. After the grouting material has initially cured (e.g., after 24 hours), remove the mold to obtain the semi-finished product.

[0075] S62 places the semi-finished product in a 60℃ cement mortar rapid curing box for a standard 28-day curing to obtain a high-temperature environment water-blocking grouting material.

[0076] Specifically, the semi-finished product after demolding is placed in a 60℃ cement mortar rapid curing chamber for a standard 28-day curing treatment. During the curing process, the hardening condition and performance changes of the grouting material are checked regularly to ensure that it meets the predetermined performance requirements.

[0077] Example 1:

[0078] The city tap water was prepared into micro-nano bubble water using a micro-nano bubble generator, and after standing for 1 hour to eliminate unstable bubbles, it was ready for use.

[0079] Mass fraction of each component: P·O42.5 ordinary Portland cement 85%, biochar 5%, rice husk ash 5%, silica fume 2%, retarder 1.5%, stabilizer 0.5%, high-efficiency water-reducing agent 1%, micro-nano bubble water 45%;

[0080] The retarder has a boric acid or sodium fluorosilicate to calcium lignosulfonate mass ratio of 1:5; the water-reducing agent has a naphthalene-based, polycarboxylic acid-based, melamine-based, and lignin-based mass ratio of 1.1:3.7:1.5:1.9.

[0081] According to the mass fraction, weighed ordinary silicate cement, biochar, rice husk ash, SiO2 aerogel, and silica fume were placed in a cement paste mixer and slowly stirred for 120 seconds. Then, according to the mass fraction, weighed retarder, stabilizer, and high-efficiency water-reducing agent were added to correspondingly weighed micro-nano bubble water and thoroughly stirred. The micro-nano bubble water solution was then poured into a mixing pot and slowly stirred for 60 seconds, followed by fast stirring for 60 seconds to obtain a mixed grouting slurry material. Next, the prepared slurry was heated at a constant temperature of 60℃ in a magnetic stirring water bath and subjected to thermophysical and mechanical property tests. Finally, the cement-based grouting material slurry was poured into a 40×40×160mm mold. After molding, the mold was removed after 24 hours, and the grout was placed in a cement mortar rapid curing box at 60℃ for a standard 28-day curing period, thus obtaining a high-temperature environment water-blocking grouting material.

[0082] The material testing specifications are as follows:

[0083] At a high temperature of 60℃, the initial setting time of cement mortar is 214 min, the final setting time is 253 min, the water separation rate is 2.18%, the 3-day, 7-day, and 21-day compressive strengths are 8.7 MPa, 9.8 MPa, and 1.1 MPa, respectively, and the thermal conductivity is 1.02 W / (m·K).

[0084] Example 2:

[0085] The city tap water was prepared into micro-nano bubble water using a micro-nano bubble generator, and after standing for 1 hour to eliminate unstable bubbles, it was ready for use.

[0086] Mass fraction of each component: P·O42.5 ordinary Portland cement 65%, biochar 4%, rice husk ash 6%, SiO2 aerogel 17%, silica fume 3%, retarder 3%, stabilizer 0.8%, high-efficiency water-reducing agent 1.2%, micro-nano bubble water 45%;

[0087] The retarder has a boric acid or sodium fluorosilicate to calcium lignosulfonate mass ratio of 1:5; the water-reducing agent has a naphthalene-based, polycarboxylic acid-based, melamine-based, and lignin-based mass ratio of 1.5:3.1:1.2:2.2.

[0088] According to the mass fraction, weighed ordinary silicate cement, biochar, rice husk ash, SiO2 aerogel, and silica fume were placed in a cement paste mixer and slowly stirred for 120 seconds. Then, according to the mass fraction, weighed retarder, stabilizer, and high-efficiency water-reducing agent were added to correspondingly weighed micro-nano bubble water and thoroughly stirred. The micro-nano bubble water solution was then poured into a mixing pot and slowly stirred for 60 seconds, followed by fast stirring for 60 seconds to obtain a mixed grouting slurry material. Next, the prepared slurry was heated at a constant temperature of 60℃ in a magnetic stirring water bath and subjected to thermophysical and mechanical property tests. Finally, the cement-based grouting material slurry was poured into a 40×40×160mm mold. After molding, the mold was removed after 24 hours, and the grout was placed in a cement mortar rapid curing box at 60℃ for a standard 28-day curing period, thus obtaining a high-temperature environment water-blocking grouting material.

[0089] The material testing parameters are as follows:

[0090] At a high temperature of 60℃, the initial setting time of cement mortar is 141 min, the final setting time is 168 min, the water separation rate is 1.58%, the 3-day, 7-day, and 21-day compressive strengths are 6.4 MPa, 8.5 MPa, and 9.1 MPa, respectively, and the thermal conductivity is 0.67 W / (m·K).

[0091] Example 3:

[0092] The city tap water was prepared into micro-nano bubble water using a micro-nano bubble generator, and after standing for 1 hour to eliminate unstable bubbles, it was ready for use.

[0093] Mass fraction of each component: P·O42.5 ordinary Portland cement 55%, biochar 5%, rice husk ash 7%, SiO2 aerogel 25%, silica fume 3.5%, retarder 2.5%, stabilizer 0.8%, high-efficiency water-reducing agent 1.2%, micro-nano bubble water 45%;

[0094] The retarder has a boric acid or sodium fluorosilicate to calcium lignosulfonate mass ratio of 1:5; the water-reducing agent has a naphthalene-based, polycarboxylic acid-based, melamine-based, and lignin-based mass ratio of 1.3:2.9:1.1:1.8.

[0095] According to the mass fraction, weighed ordinary silicate cement, biochar, rice husk ash, SiO2 aerogel, and silica fume were placed in a cement paste mixer and slowly stirred for 120 seconds. Then, according to the mass fraction, weighed retarder, stabilizer, and high-efficiency water-reducing agent were added to correspondingly weighed micro-nano bubble water and thoroughly stirred. The micro-nano bubble water solution was then poured into a mixing pot and slowly stirred for 60 seconds, followed by fast stirring for 60 seconds to obtain a mixed grouting slurry material. Next, the prepared slurry was heated at a constant temperature of 60℃ in a magnetic stirring water bath and subjected to thermophysical and mechanical property tests. Finally, the cement-based grouting material slurry was poured into a 40×40×160mm mold. After molding, the mold was removed after 24 hours, and the grout was placed in a cement mortar rapid curing box at 60℃ for a standard 28-day curing period, thus obtaining a high-temperature environment water-blocking grouting material.

[0096] The material testing specifications are as follows:

[0097] At a high temperature of 60℃, the initial setting time of cement mortar is 134 min, the final setting time is 153 min, the water separation rate is 1.44%, the 3-day, 7-day, and 21-day compressive strengths are 5.4 MPa, 6.8 MPa, and 7.6 MPa, respectively, and the thermal conductivity is 0.62 W / (m·K).

[0098] Example 4:

[0099] The city tap water was prepared into micro-nano bubble water using a micro-nano bubble generator, and after standing for 1 hour to eliminate unstable bubbles, it was ready for use.

[0100] Mass fraction of each component: P·O42.5 ordinary Portland cement 40%, biochar 7%, rice husk ash 8%, SiO2 aerogel 35%, silica fume 4%, retarder 3.2%, stabilizer 1.2%, high-efficiency water-reducing agent 1.6%, micro-nano bubble water 45%;

[0101] The retarder has a boric acid or sodium fluorosilicate to calcium lignosulfonate mass ratio of 1:5; the water-reducing agent has a naphthalene-based, polycarboxylic acid-based, melamine-based, and lignin-based mass ratio of 1.2:2.5:1.8:2.5.

[0102] According to the mass fraction, weighed ordinary silicate cement, biochar, rice husk ash, SiO2 aerogel, and silica fume were placed in a cement paste mixer and slowly stirred for 120 seconds. Then, according to the mass fraction, weighed retarder, stabilizer, and high-efficiency water-reducing agent were added to correspondingly weighed micro-nano bubble water and thoroughly stirred. The micro-nano bubble water solution was then poured into a mixing pot and slowly stirred for 60 seconds, followed by fast stirring for 60 seconds to obtain a mixed grouting slurry material. Next, the prepared slurry was heated at a constant temperature of 60℃ in a magnetic stirring water bath and subjected to thermophysical and mechanical property tests. Finally, the cement-based grouting material slurry was poured into a 40×40×160mm mold. After molding, the mold was removed after 24 hours, and the grout was placed in a cement mortar rapid curing box at 60℃ for a standard 28-day curing period, thus obtaining a high-temperature environment water-blocking grouting material.

[0103] The material testing specifications are as follows:

[0104] At a high temperature of 60℃, the initial setting time of cement mortar is 145 min, the final setting time is 176 min, the water separation rate is 1.24%, the 3-day, 7-day, and 21-day compressive strengths are 4.2 MPa, 5.3 MPa, and 6.2 MPa, respectively, and the thermal conductivity is 0.54 W / (m·K).

[0105] As can be seen from the above four implementation schemes, the high-temperature fractured rock mass water-blocking and heat-insulating grouting material prepared by this invention, while meeting the compressive strength requirements, can achieve a minimum thermal conductivity of 0.54 W / (m·K). Compared with the thermal conductivity of existing ordinary cement grouting materials (1.18 W / (m·K)) and cement-water glass grouting materials (1.14 W / (m·K), the invented grouting and heat-insulating material reduces these coefficients by 52.63% and 54.24%, respectively, effectively blocking heat flow. The optimal material ratio is recommended as follows: cement: biochar: rice husk ash: SiO2 aerogel: nano-bubble water: retarder: stabilizer: water-reducing agent = 1.00: 0.18: 0.20: 0.88: 0.10: 0.08: 0.04: 0.04. Appropriate addition of biochar and rice husk ash to the material can not only reduce the thermal conductivity of the grout to a certain extent, but also develop green, environmentally friendly, and energy-saving geopolymer grouting materials. The addition of SiO2 aerogel and micro-nano bubble water made by micro-nano bubble generator can form a closed porous structure in the cement grout, which can greatly improve the thermal insulation performance of the grouting material and has great application value in high geothermal fracture rock mass environment.

[0106] Secondly, the water-blocking and heat-insulating grouting material adapted to high-temperature fractured rock masses adopts the preparation method of the water-blocking and heat-insulating grouting material adapted to high-temperature fractured rock masses described in the first aspect, including cement, biochar, rice husk ash, SiO2 aerogel, silica fume, retarder, stabilizer, water-reducing agent and micro-nano bubble water.

[0107] Beneficial effects:

[0108] I. Significantly Improved Thermal Insulation Performance: By rationally proportioning raw materials such as cement, biochar, rice husk ash, and SiO2 aerogel, and combining the unique properties of micro-nano bubble water, the prepared grouting material exhibits a significantly reduced thermal conductivity, reaching as low as 0.54 W / (m·K). Compared to traditional cement grouting materials and cement-water glass grouting materials, the thermal conductivity is reduced by 52.63% and 54.24%, respectively. This characteristic enables the grouting material to effectively block heat flow conduction in high-temperature fractured rock environments, providing strong protection for the stability and safety of underground engineering projects.

[0109] Second, it improves the water-blocking performance and effect of grouting materials in high geothermal environments, enabling the grouting range to be reached and improving the water-blocking effect, etc.

[0110] III. Green Environmental Protection and Resource Recycling: The reuse of biochar and rice husk ash as agricultural waste not only reduces environmental pollution but also achieves resource recycling. Meanwhile, the addition of high-performance materials such as SiO2 aerogel enhances the overall performance of the grouting material, making it more environmentally friendly and efficient.

[0111] IV. Optimizing material performance and construction efficiency: Through precise component design and preparation process, the grouting material exhibits excellent performance in terms of strength, thermal insulation and stability.

[0112] V. Broad Application Prospects: The grouting material prepared by this invention is not only suitable for water control and thermal insulation protection of high-temperature fractured rock masses, but also for geological disaster management, underground resource development, and waterproofing, leak sealing, and thermal insulation protection of underground pipelines, tunnels, and other underground engineering projects. Its broad application prospects and huge market potential provide strong support for the advancement and sustainable development of underground engineering technology.

[0113] The above-disclosed embodiments are merely preferred embodiments of the water-blocking and heat-insulating grouting material and preparation method adapted to high-temperature fractured rock masses of the present invention. Of course, they should not be construed as limiting the scope of the present invention. Those skilled in the art can understand that all or part of the processes of the above embodiments can be implemented, and equivalent changes made in accordance with the claims of the present invention still fall within the scope of the invention.

Claims

1. A method for preparing grouting material suitable for high-temperature fractured rock masses, characterized in that: Includes the following steps: Weigh out cement, biochar, rice husk ash, SiO2 aerogel, silica fume, retarder, stabilizer, water-reducing agent, and micro / nano bubble water according to the preset mass fraction; Cement, biochar, rice husk ash, SiO2 aerogel, and silica fume are placed in a cement paste mixer and slowly mixed for 120 seconds to obtain a mixture. The retarder, stabilizer, and water-reducing agent are added to the micro-nano bubble water and mixed and stirred to obtain a micro-nano bubble aqueous solution; The micro-nano bubble aqueous solution and the mixture were added to a mixing pot and stirred slowly for 60 seconds and then stirred rapidly for 60 seconds to obtain a mixed grouting slurry material. In the process of "weighing cement, biochar, rice husk ash, SiO2 aerogel, silica fume, retarder, stabilizer, water-reducing agent, and micro / nano bubble water according to preset mass fractions," the mass fraction of cement is 55-65%; the mass fraction of biochar is 4-5%; the mass fraction of rice husk ash is 6-8%; the mass fraction of SiO2 aerogel is 17-25%; the mass fraction of silica fume is 3-4%; the mass fraction of retarder is 3-3.2%; the mass fraction of stabilizer is 0.8-1.2%; the mass fraction of water-reducing agent is 1.2-1.5%; and the mass fraction of micro / nano bubble water is 45%. The micro-nano bubble water has a bubble diameter of 10-200 nm and a bubble concentration of 10. 8 -10 9 per ml.

2. The method for preparing grouting material adapted to high-temperature fractured rock masses as described in claim 1, characterized in that: In the phrase "weighing cement, biochar, rice husk ash, SiO2 aerogel, silica fume, retarder, stabilizer, water-reducing agent, and micro / nano bubble water according to preset mass fractions", the cement is ordinary silicate cement with a strength grade of not less than 42.5 MPa; the biochar is made by pyrolysis of wheat straw in a partially anaerobic environment; the retarder is boric acid or sodium fluorosilicate, or calcium lignosulfonate; the stabilizer is any one of cellulose ether, polyvinyl alcohol, or water-soluble starch; and the micro / nano bubble water is a non-chemical liquid medium containing nano-sized bubbles.

3. The method for preparing grouting material adapted to high-temperature fractured rock masses as described in claim 1, characterized in that: In the process of "weighing cement, biochar, rice husk ash, SiO2 aerogel, silica fume, retarder, stabilizer, water-reducing agent, and micro / nano bubble water according to preset mass fractions," the biochar has a particle size ≤100 mesh; the SiO2 aerogel has a thermal conductivity of 0.013-0.020 W / (m·K), a particle size ≤3 mm, a pore size of 20-40 nm, and a porosity >90%; and the silica fume has an average particle size of 0.1-0.3 μm and a density of 2.33 g / cm³. 3 Its specific surface area is 20.5 m². 2 ·kg.

4. The method for preparing grouting material adapted to high-temperature fractured rock masses as described in claim 1, characterized in that: The process of "placing cement, biochar, rice husk ash, SiO2 aerogel, and silica fume into a cement paste mixer and slowly mixing for 120 seconds to obtain a mixture" includes the following steps: Cement, biochar, rice husk ash, SiO2 aerogel, and silica fume are placed into the mixer in sequence; Set the mixer to slow speed mode and mix for 120 seconds; After mixing is complete, turn off the mixer and use a scraper to remove the mixture from the mixer and place it in a clean container for later use.

5. The method for preparing grouting material adapted to high-temperature fractured rock masses as described in claim 1, characterized in that: The process of "mixing and stirring retarder, stabilizer, and water-reducing agent in micro-nano bubble water to obtain micro-nano bubble aqueous solution" includes the following steps: Add the weighed retarder, stabilizer, and water-reducing agent to the container containing micro-nano bubble water in sequence; After setting the stirring speed of the electric mixer, mix the materials in the container. Remove the micro-nano bubble aqueous solution from the container for later use.

6. The method for preparing grouting material adapted to high-temperature fractured rock masses as described in claim 1, characterized in that: The process of "adding the micro / nano bubble aqueous solution and mixture into a mixing tank and stirring slowly for 60 seconds followed by rapid stirring for 60 seconds to obtain a mixed grouting slurry material" includes the following steps: The prepared mixture and the micro / nano bubble aqueous solution were added separately into the mixing vessel; Set the mixing bowl to the slow mixing mode and mix for 60 seconds. Set the mixing bowl to the rapid mixing mode and mix for 60 seconds. After mixing is complete, close the mixing pot and use a scraper to remove the mixed grouting material from the mixing pot and place it in a container for later use.

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