Cement-based composite grouting material and method for reinforcing deep broken surrounding rock

Abstract

The invention provides a cement-based composite grouting material and method for reinforcing deep broken surrounding rock, and belongs to the technical field of grouting materials. The high-performance cement-based composite material is prepared from the following components in parts by weight: 100 to 200 parts of a Portland cement matrix, 20 to 70 parts of a multi-element active mineral admixture, 5 to 30 parts of hollow glass beads, 0.2 to 4.0 parts of aluminum oxide powder, 0.1 to 0.4 part of powdery graphene oxide, 0.5 to 3.0 parts of a polycarboxylate superplasticizer and 60 to 100 parts of water. The problems that in deep broken surrounding rock reinforcement, a traditional cement-based grouting material is difficult to consider bearing capacity and dynamic disturbance resistance at the same time, performance is degraded at the high temperature, and all components are not dispersed are solved; the material has the characteristics of dynamic wave absorbing performance, high strength, excellent flow diffusivity, high temperature resistance and the like, and can effectively reinforce surrounding rocks in high-stress, high-ground-temperature and dynamic disturbance environments.

Description

Technical Field

[0001] The present invention relates to the technical field of grouting materials, and particularly to a cement-based composite grouting material and method for reinforcing deep broken surrounding rock. Background Art

[0002] With the continuous advancement of deep underground engineering construction, such as mine exploitation and deep-buried tunnel excavation, the problem of reinforcing deep broken surrounding rock has become increasingly prominent. The geological environment where deep underground engineering is located is extremely complex, with the characteristics of "three highs and one disturbance", namely high ground stress, high ground temperature, high pore water pressure and dynamic disturbance, which poses great challenges to traditional surrounding rock reinforcement technologies.

[0003] In traditional grouting reinforcement of deep broken surrounding rock, ordinary cement-based grouting materials are commonly used. However, there are many insurmountable problems with such materials. On the one hand, the performance requirements for the slurry solidified body for improving the bearing capacity and anti-dynamic disturbance of broken surrounding rock are contradictory. To improve the bearing capacity, the slurry solidified body needs to be more dense, while to enhance the anti-dynamic disturbance, a controllable pore structure needs to be constructed in the solidified body to dissipate the energy of dynamic waves, and ordinary cement-based materials are difficult to meet these two requirements simultaneously. On the other hand, the thermal-mechanical coupling effect generated by the high ground temperature environment underground and high ground stress and dynamic disturbance will significantly exacerbate the decomposition of the hydration products of the solidified body of ordinary cement-based grouting materials, resulting in a non-linear attenuation of the comprehensive performance of the solidified body. In practical applications, when ordinary cement-based grouting materials are used for reinforcing deep broken surrounding rock, situations such as secondary instability failure of the surrounding rock or dynamic response failure often occur, seriously affecting the safety and stability of the project. Summary of the Invention

[0004] In order to overcome the deficiencies of the prior art, the purpose of the present invention is to provide a cement-based composite grouting material and method for reinforcing deep broken surrounding rock, which solves the problems existing in the reinforcement of deep broken surrounding rock by traditional cement-based grouting materials, such as the difficulty in taking into account both the bearing capacity and anti-dynamic disturbance, performance attenuation at high temperatures, and uneven dispersion of each component. By adding hollow glass microspheres, graphene oxide and alumina powder, the material has the characteristics of dynamic wave dissipation performance, high strength, excellent flow and diffusion performance and high temperature resistance, and can effectively reinforce the surrounding rock under high stress, high ground temperature and dynamic disturbance environments.

[0005] To achieve the above purpose, the present invention provides the following solutions:

[0006] A cement-based composite grouting material for reinforcing deep broken surrounding rock, by weight, comprises the following components: 100-200 parts of a portland cement matrix, 20-70 parts of a multi-component active mineral admixture, 5-30 parts of hollow glass microspheres, 0.2-4.0 parts of alumina powder, 0.1-0.4 parts of powdered graphene oxide, 0.5-3.0 parts of a polycarboxylate water reducer, and 60-100 parts of water.

[0007] Preferably, the multi-component active mineral admixture is composed of 10-30 parts of blast furnace slag, 5-20 parts of silica fume and 5-20 parts of fly ash.

[0008] Preferably, the specific surface area of the blast furnace slag is 350-380 m 2 / kg; the SiO2 content in the silica fume is greater than 85%, and the specific surface area is not greater than 15 m 2 / kg.

[0009] Preferably, the particle size of the hollow glass microspheres is 10μm-30μm, the density is 0.4-0.5 g / cm 3 , and the crushing strength is not less than 60 MPa.

[0010] Preferably, the graphene oxide is prepared from graphite powder by Hummer's process, and the graphene oxide has a sheet diameter greater than 5μm, a single-layer thickness of 0.8-1.2 nm, and a number of layers of 1-5 layers.

[0011] Preferably, the average particle size of the alumina powder is 0.77μm, and the density is 4.0 g / cm 3 .

[0012] The present invention also provides a preparation method of the cement-based composite grouting material for deep broken surrounding rock reinforcement as described above, including the following steps:

[0013] S1. According to the set ratio, the portland cement matrix, hollow glass microspheres, silica fume, fly ash and alumina powder are sequentially added to the mixing tank and stirred and mixed evenly to obtain dry materials;

[0014] S2. The polycarboxylate water reducer and powdered graphene oxide are added to water and stirred evenly to obtain a graphene oxide aqueous dispersion;

[0015] S3. The graphene oxide aqueous dispersion is added to the dry materials, and continuous stirring is carried out and the water amount is adjusted until the slurry is uniform and has the fluidity meeting the construction requirements, thereby obtaining the cement-based composite grouting material.

[0016] Preferably, in step S1, the dry materials are prepared by stirring the mixture at a speed of 300 rpm for 3 min by a stirring device; in step S2, the graphene oxide aqueous dispersion is prepared by stirring at a speed of 500 rpm until the graphene oxide is evenly dispersed; in step S3, the cement-based composite grouting material is prepared by continuously stirring at a speed of 500 rpm for 3 min.

[0017] Preferably, in step S2, the mass concentration of the graphene oxide aqueous dispersion is not greater than 4 mg / mL.

[0018] The present invention also provides an application method of the cement-based composite grouting material for reinforcing deep broken surrounding rock as described above, including the following steps:

[0019] Open grouting holes in the deep broken surrounding rock area and embed grouting pipes, and then use grouting equipment to inject the slurry of the cement-based composite grouting material into the fissures or broken zones of the surrounding rock;

[0020] During the grouting process, control the grouting pressure to be not less than 1.8 MPa and the grouting volume and flow rate to ensure that the slurry can be evenly and fully filled inside the surrounding rock fissures;

[0021] According to the construction environment and conditions, adjust the fluidity and setting time of the slurry. After the grouting operation is completed, the slurry naturally solidifies and fully hardens to form a stable reinforcement layer, completing the grouting reinforcement of the deep broken surrounding rock.

[0022] According to the specific embodiments provided by the present invention, the following technical effects are disclosed:

[0023] (1) By introducing hollow glass microspheres in the slurry solidified body to form independently distributed spherical closed micropores, the present invention can not only significantly improve the dynamic wave dissipation efficiency of the material, but also effectively block the heat conduction path, thereby inhibiting the thermal cracking of the slurry solidified body. At the same time, the high compressive strength characteristics of the hollow glass microspheres enable the micropore area to also transmit stress, avoiding the reduction of material strength due to the increase in porosity; by incorporating graphene oxide to promote the hydration reaction of the slurry, and its two-dimensional sheet-like nanostructure can inhibit the microcrack propagation of the slurry solidified body through nano-bridging action, realizing the strengthening of the bearing performance of the material; by incorporating micron-sized alumina powder to form a high-temperature stable phase, significantly improving the high-temperature resistance of the slurry solidified body. The "soft wave dissipation - hard bearing - high-temperature stability" mechanism formed by the synergistic action of hollow glass microspheres, graphene oxide and alumina powder makes the material of the present invention have better environmental adaptability in deep underground engineering.

[0024] (2) The cement-based composite grouting material provided by the present invention has a wide range of raw material sources. While meeting the reinforcement requirements of deep broken surrounding rock, it practices the concept of low-carbon environmental protection. This not only reduces the dependence on scarce resources, reduces the energy consumption and pollution in the material production process, but also provides strong support for the sustainable development of deep underground engineering; at the same time, the material has good fluidity and diffusibility, can be smoothly transmitted and evenly distributed in the complex fissures of deep broken surrounding rock; during grouting construction, the fluidity and setting time of the slurry can be adjusted according to different construction conditions, and by controlling the grouting pressure, grouting volume and flow rate, it is ensured that the slurry fully fills the surrounding rock fissures, improving the construction efficiency and reinforcement effect, and providing a reliable guarantee for the smooth progress of deep underground engineering.

[0025] (3) The present invention solves the problems existing in the ordinary cement-based grouting materials for deep broken surrounding rock reinforcement, such as the difficulty in balancing the bearing capacity and anti-dynamic disturbance performance, the performance attenuation at high temperatures, and the uneven dispersion of each component. By adding hollow glass microspheres, graphene oxide and alumina powder, the material has the characteristics of dynamic wave attenuation, high strength, excellent flow diffusion and high temperature resistance, and can effectively reinforce the surrounding rock in the environment of high stress, high geothermal temperature and dynamic disturbance. Brief Description of the Drawings

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0027] Figure 1 It is a flowchart of the preparation method of a cement-based composite grouting material for deep broken surrounding rock reinforcement according to the present invention;

[0028] Figure 2 It is a flowchart of the application method of a cement-based composite grouting material for deep broken surrounding rock reinforcement according to the present invention. Detailed Embodiments

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0030] To make the above objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0031] As Figure 1 shown, the present invention provides a cement-based composite grouting material for deep broken surrounding rock reinforcement and its preparation method, including the following steps:

[0032] S1. According to the set ratio, add the Portland cement matrix, hollow glass microspheres, silica fume, fly ash and alumina powder into the mixing tank in sequence, and stir and mix evenly to obtain dry materials;

[0033] S2. Add the polycarboxylate superplasticizer and powdered graphene oxide into water, and stir evenly to obtain a graphene oxide aqueous dispersion;

[0034] S3. Add the graphene oxide aqueous dispersion to the dry material, continuously stir and adjust the water volume until the slurry becomes uniform and has the fluidity meeting the construction requirements, thereby obtaining the cement-based composite grouting material.

[0035] Among them, in step S1, the dry material is prepared by stirring the mixture at a speed of 300 rpm for 3 minutes with a stirring device; in step S2, the graphene oxide aqueous dispersion is prepared by stirring at a speed of 500 rpm until the graphene oxide is uniformly dispersed, and the mass concentration of the graphene oxide aqueous dispersion is not more than 4 mg / mL; in step S3, the cement-based composite grouting material is prepared by continuously stirring at a speed of 500 rpm for 3 minutes.

[0036] In the above content, the cement-based composite grouting material, by weight, comprises the following components: 100 - 200 parts of a portland cement matrix, 20 - 70 parts of a multi-component active mineral admixture, 5 - 30 parts of hollow glass microspheres, 0.2 - 4.0 parts of alumina powder, 0.1 - 0.4 parts of powdered graphene oxide, 0.5 - 3.0 parts of a polycarboxylate water reducer, and 60 - 100 parts of water.

[0037] Among them, the multi-component active mineral admixture consists of 10 - 30 parts of blast furnace slag, 5 - 20 parts of silica fume, and 5 - 20 parts of fly ash. The specific surface area of the blast furnace slag is 350 - 380 m 2 / kg; the SiO2 content in the silica fume is greater than 85%, and the specific surface area is not more than 15 m 2 / kg.

[0038] In the above raw material composition, the particle size of the hollow glass microspheres is 10 μm - 30 μm, the density is 0.4 - 0.5 g / cm 3 , and the crushing strength is not less than 60 MPa. The graphene oxide is prepared from graphite powder by the Hummer's process, and the sheet diameter of the graphene oxide is greater than 5 μm, the single-layer thickness is 0.8 - 1.2 nm, and the number of layers is 1 - 5 layers. The average particle size of the alumina powder is 0.77 μm, and the density is 4.0 g / cm 3 .

[0039] Referring to Figure 2 , for the cement-based composite grouting material obtained above, its application method comprises the following steps:

[0040] Step 100. Open grouting holes in the area of deep broken surrounding rock, embed grouting pipes, and then use a grouting device to inject the slurry of the cement-based composite grouting material into the fissures or broken zones of the surrounding rock;

[0041] Step 200: During the grouting process, control the grouting pressure to be not less than 1.8 MPa, as well as the grouting volume and flow rate, to ensure that the grout can uniformly and fully fill the internal cracks of the surrounding rock;

[0042] Step 300: According to the construction environment and conditions, adjust the fluidity and setting time of the grout. After the grouting operation is completed, the grout naturally cures and fully hardens to form a stable reinforcement layer, completing the grouting reinforcement of the deeply broken surrounding rock.

[0043] The following further elaborates on the cement-based composite grouting material of the present invention through specific embodiments.

[0044] Example 1

[0045] In this example, the cement-based composite grouting material is prepared from the following raw materials: 100 parts of a portland cement matrix, 12 parts of blast furnace slag, 8 parts of silica fume, 8 parts of fly ash, 10 parts of hollow glass microspheres, 1 part of a polycarboxylate water reducer, 1.5 parts of alumina powder, 0.2 part of powdered graphene oxide, and 60 parts of water.

[0046] The specific preparation process is as follows: According to the proportion requirements of this example, the portland cement matrix, hollow glass microspheres, silica fume, fly ash, and alumina powder are sequentially added to a mixing tank, and the above components are stirred for 3 minutes at a speed of 300 rpm using a stirring device to obtain dry materials; subsequently, the polycarboxylate water reducer and powdered graphene oxide are added to 50 parts of water and stirred at a speed of 500 rpm until the graphene oxide is uniformly dispersed to obtain a graphene oxide aqueous dispersion; then the graphene oxide aqueous dispersion is added to the dry materials and continuously stirred at a speed of 500 rpm for 3 minutes, and the remaining 10 parts of water are added to the slurry during the stirring process until the slurry is uniform and has a fluidity that meets the construction requirements; finally, through steps such as standing and screening, the cement-based composite grouting material is obtained.

[0047] Example 2

[0048] In this example, the difference from Example 1 is that the selected hollow glass microspheres in this example are 5 parts, and the powdered graphene oxide is 0.1 part, and the other raw material ratios and preparation methods are the same as those in Example 1.

[0049] Example 3

[0050] In this example, the difference from Example 1 is that the selected hollow glass microspheres in this example are 6 parts, and the powdered graphene oxide is 0.15 part, and the other raw material ratios and preparation methods are the same as those in Example 1.

[0051] Example 4

[0052] In this embodiment, the difference from Embodiment 1 is that the selected hollow glass microspheres are 7.5 parts, and the powdered graphene oxide is 0.18 part. The other raw material ratios and preparation methods are the same as those in Embodiment 1.

[0053] Embodiment 5

[0054] In this embodiment, the difference from Embodiment 1 is that the selected hollow glass microspheres are 9 parts, and the powdered graphene oxide is 0.2 part. The other raw material ratios and preparation methods are the same as those in Embodiment 1.

[0055] Embodiment 6

[0056] In this embodiment, the difference from Embodiment 1 is that the selected hollow glass microspheres are 12.5 parts, and the powdered graphene oxide is 0.24 part. The difference in the preparation method of this embodiment from that of Embodiment 1 is that the polycarboxylate water reducer and the powdered graphene oxide are added to 60 parts of water and stirred at a speed of 500 rpm until the graphene oxide is evenly dispersed to obtain a graphene oxide aqueous dispersion; then the graphene oxide aqueous dispersion is added to the dry materials and continuously stirred at a speed of 500 rpm for 3 min until the slurry is uniform and has the fluidity to meet the construction requirements; finally, through steps such as standing and screening, a cement-based composite grouting material is obtained.

[0057] Comparative Example 1

[0058] The preparation method of this comparative example is the same as that of Embodiment 1, and the difference is that no hollow glass microspheres, graphene oxide, and alumina powder are added in this comparative example.

[0059] According to the above content, various performance tests are carried out on the cement-based composite grouting materials obtained in Embodiments 1 to 6 and Comparative Example 1, and the test results are shown in Table 1:

[0060] Table 1 Test Results

[0061]

[0062] In Table 1, the calculation formula for the compressive strength decay rate after high temperature is:

[0063]

[0064] Wherein σ1 and σ0 are the static compressive strengths of the cement-based composite grouting material before and after high-temperature treatment, respectively. The high-temperature treatment condition is to continue for 2 hours at a temperature of 400 °C.

[0065] As can be seen from Table 1, the static compressive strength of the cement-based composite grouting materials prepared in Examples 1 to 6 is not significantly reduced compared with that of the ordinary cement-based grouting materials, but there are significant improvements in terms of fluidity, setting time, dynamic compressive strength and strength attenuation rate after high temperature. At the same time, the comprehensive performance of the cement-based composite grouting materials prepared in Examples 1 to 6 is significantly improved compared with that of the ordinary cement-based grouting materials.

[0066] Therefore, by using the above-mentioned cement-based composite grouting material and method for deep broken surrounding rock reinforcement, the problems existing in the traditional cement-based grouting material for deep broken surrounding rock reinforcement, such as the difficulty in taking into account both bearing capacity and anti-dynamic disturbance, performance attenuation at high temperature, uneven dispersion of each component, etc., are solved. By adding hollow glass microspheres, graphene oxide and alumina powder, the material has the characteristics of dynamic wave attenuation, high strength, excellent flow diffusion and high temperature resistance, and can effectively reinforce the surrounding rock under the environment of high stress, high geothermal temperature and dynamic disturbance.

[0067] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. The same or similar parts among the embodiments can be referred to each other.

[0068] In this article, specific examples are used to elaborate on the principles and implementation modes of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation mode and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A cement-based composite grouting material for reinforcing deeply broken surrounding rock, characterized in that, By weight parts, it includes the following components: 100 - 200 parts of silicate cement matrix, 20 - 70 parts of multi-component active mineral admixture, 5 - 30 parts of hollow glass microspheres, 0.2 - 4.0 parts of alumina powder, 0.1 - 0.4 parts of powdered graphene oxide, 0.5 - 3.0 parts of polycarboxylate superplasticizer, and 60 - 100 parts of water.

2. The cement-based composite grouting material for deep broken surrounding rock reinforcement according to claim 1, characterized in that, The multi-component active mineral admixture is composed of 10 - 30 parts of blast furnace slag, 5 - 20 parts of silica fume, and 5 - 20 parts of fly ash.

3. The cement-based composite grouting material for deep broken surrounding rock reinforcement according to claim 2, characterized in that, The specific surface area of the blast furnace slag is 350 - 380 m 2 / kg; the SiO2 content in the silica fume is greater than 85%, and the specific surface area is not greater than 15 m 2 / kg.

4. The cement-based composite grouting material for reinforcing deeply broken surrounding rock according to claim 1, characterized in that, The particle size of the hollow glass microspheres is 10μm - 30μm, and the density is 0.4 - 0.5 g / cm 3 , and the crushing strength is not less than 60 MPa.

5. The cement-based composite grouting material for deep broken surrounding rock reinforcement according to claim 1, characterized in that, The graphene oxide is prepared from graphite powder by Hummer’s process, and the graphene oxide has a sheet diameter greater than 5μm, a single-layer thickness of 0.8 - 1.2nm, and a number of layers of 1 - 5 layers.

6. The cement-based composite grouting material for reinforcing deeply broken surrounding rock according to claim 1, characterized in that, The average particle size of the alumina powder is 0.77 μm and the density is 4.0 g / cm 3 .

7. A preparation method of a cement-based composite grouting material for reinforcing deeply broken surrounding rock according to any one of claims 1 to 6, characterized in that, It includes the following steps: S1. According to the set ratio, the silicate cement matrix, hollow glass microspheres, silica fume, fly ash, and alumina powder are sequentially added to a mixing tank and stirred and mixed evenly to obtain dry materials. S2. The polycarboxylate superplasticizer and powdered graphene oxide are added to water and stirred evenly to obtain a graphene oxide aqueous dispersion. S3. The graphene oxide aqueous dispersion is added to the dry materials, and continuous stirring is carried out while adjusting the water volume until the slurry is uniform and has a fluidity that meets the construction requirements, thereby obtaining a cement-based composite grouting material.

8. The preparation method of the cement-based composite grouting material for deep broken surrounding rock reinforcement according to claim 7, characterized in that, In step S1, the dry materials are prepared by stirring the mixture at a speed of 300 rpm for 3 min using a stirring device; in step S2, the graphene oxide aqueous dispersion is prepared by stirring at a speed of 500 rpm until the graphene oxide is evenly dispersed; in step S3, the cement-based composite grouting material is prepared by continuously stirring at a speed of 500 rpm for 3 min.

9. The preparation method of the cement-based composite grouting material for reinforcing deeply broken surrounding rock according to claim 8, characterized in that, In step S2, the mass concentration of the graphene oxide aqueous dispersion is not greater than 4 mg / mL.

10. A method for applying a cement-based composite grouting material for reinforcing deeply broken surrounding rock according to any one of claims 1 to 6, characterized in that, It includes the following steps: Grouting holes are opened in the deep broken surrounding rock area, and grouting pipes are buried. Subsequently, the slurry of the cement-based composite grouting material is injected into the cracks or broken zones of the surrounding rock using a grouting device. During the grouting process, the grouting pressure is controlled to be not less than 1.8 MPa, as well as the grouting volume and flow rate, to ensure that the slurry can be evenly and fully filled inside the surrounding rock cracks. According to the construction environment and conditions, the fluidity and setting time of the slurry are adjusted. After the grouting operation is completed, the slurry naturally cures and fully hardens to form a stable reinforcement layer, completing the grouting reinforcement of the deep broken surrounding rock.

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