Bi-component grouting material for reinforcing shallow hole of surrounding rock of coal mine tunnel

Abstract

The invention belongs to the technical field of grouting materials for coal mine tunnels, and particularly relates to a bi-component grouting material for reinforcing shallow holes of surrounding rock of a coal mine tunnel. The bi-component grouting material for reinforcing the shallow hole of the surrounding rock of the coal mine tunnel comprises a component A and a component B, the component A is prepared from the following solid components in parts by mass: 80 to 90 parts of sulphoaluminate cement clinker, 10 to 20 parts of denitration ash and 0.1 to 0.3 part of a water reducing agent; the component B comprises the following solid components in parts by weight: 64-72 parts of well salt gypsum, 16-18 parts of quick lime, 10-20 parts of denitration ash and 0.2-0.4 part of a water reducing agent. According to the double-component grouting material for reinforcing the shallow hole of the surrounding rock of the coal mine tunnel, a large amount of well salt gypsum and denitration ash which are difficult to recycle are adopted, the double-component grouting material is green and environmentally friendly, energy is saved, carbon is reduced, the treatment process is simple, and the production cost is remarkably reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of grouting materials for coal mine roadway, and particularly relates to a two-component grouting material for shallow hole reinforcement of surrounding rock of coal mine roadway. BACKGROUND

[0002] The coal mine roadway is often affected by high ground stress and mining stress, which leads to poor stability of surrounding rock and very serious deformation and damage, thus bringing major safety hazards to production and operation. Anchor cable net reinforcement is a common measure, but when the surrounding rock is severely broken or the lithology of the surrounding rock is soft rock, the supporting effect is very limited, and grouting reinforcement must be used in combination.

[0003] To ensure the reinforcement effect of the surrounding rock of the roadway, a deep-shallow hole grouting process is often used, that is, shallow hole grouting is first performed to seal the surface of the shallow surrounding rock, and then deep hole grouting is performed, so that the shallow hole surrounding rock of the roadway and the deep surrounding rock are cemented to form an arched continuous body reinforcement ring. The hole depth of the shallow hole grouting is usually within 3m. Since the shallow surrounding rock of the roadway is the most severely broken, the degree of fissure development is high, and the connectivity is strong, when the shallow hole grouting is implemented, the grouting material must have the characteristics of fast diffusion and fast hardening, so as to ensure that the surrounding rock fissures within a certain range are quickly filled, and the amount of grouting leakage is reduced. Due to the special environmental conditions of coal mines, flammable organic grouting materials such as polyurethane have been prohibited. At present, ordinary cement-silicate grouting materials and sulphoaluminate cement-based grouting materials are mainly used for shallow holes, but the former hardens too fast, which easily causes the grouting pipe to be scrapped, and the diffusion radius is small, the reinforcement effect is poor, and the maintenance frequency is high.

[0004] Sulphoaluminate cement-based grouting material has the characteristics of accurate setting time, fast strength development and micro-expansion of the set body, which is very suitable for roadway surrounding rock reinforcement. The sulphoaluminate cement-based grouting material for surrounding rock reinforcement is usually composed of two components A and B, wherein the main component of component A is sulphoaluminate cement clinker, and the main component of component B is anhydrite and quicklime. In addition, in order to meet the needs of grouting construction, the A component and the B component need to maintain high fluidity and suspension stability without solidification after being mixed with water and grouted respectively for a certain period of time, and need to spread to a certain range of cracks and quickly set and harden in a short period of time after mixing. Therefore, it is also necessary to add modifiers, such as water reducing agent to ensure strength and improve fluidity; thickening agent (or suspending agent) such as bentonite and cellulose ether to adjust the viscosity of the slurry and reduce particle settling. In addition, in order to ensure that the A component slurry can maintain good fluidity for a long time, it is often necessary to add an appropriate retarder (such as sodium gluconate) to delay the hydration of sulphoaluminate cement clinker. For example, ZL201310642046.9 adds water reducing agent, early strength agent, retarder and suspending agent to component A, and adds water reducing agent, accelerator, retarder and suspending agent to component B, which has too many admixtures, high requirements for the stability of the performance of the admixtures, and increases the complexity of production, resulting in a substantial increase in production cost. ZL201010508276.2 uses desulfurization gypsum instead of anhydrite, but desulfurization gypsum is in the form of powder, and has a single particle size distribution (40μm-60μm), which has little effect on the viscosity of the B component slurry, causing particle settling during slurry static placement, which requires the addition of bentonite to adjust the viscosity of the slurry. Although fine grinding can improve this situation, the grinding efficiency is greatly reduced, resulting in a substantial increase in cost.

[0005] In general, the sulphoaluminate cement-based two-component grouting material has too many types of admixtures or a complex production process, resulting in a high market price (more than 3000 yuan / ton), which makes it difficult to be widely applied in coal mines.

[0006] Therefore, it is necessary to provide an improved technical solution to the above-mentioned deficiencies of the prior art. SUMMARY

[0007] The purpose of the present application is to provide a two-component grouting material for shallow hole reinforcement of coal mine roadway surrounding rock, which helps to solve or improve the problem of too many admixtures or high cost of the grouting material in the prior art.

[0008] In order to achieve the above object, the present application provides the following technical scheme: A kind of coal mine roadway surrounding rock shallow hole reinforcement is with two-component grouting material, the grouting material includes A component and B component;The solid component of the A component includes: sulphoaluminate cement clinker 80-90 parts, desulfurization ash 10-20 parts and water reducing agent 0.1-0.3 parts by mass fraction;The solid component of the B component includes: well salt gypsum 64-72 parts, quicklime 16-18 parts, desulfurization ash 10-20 parts and solid water reducing agent 0.2-0.4 parts.

[0009] Preferably, the desulfurization ash is the solid waste discharged after coal gasification using SCR denitrification technology in coal chemical industry, which is ground to a particle size D 95 ≤20 μm.

[0010] Preferably, the well salt gypsum is the waste residue of brine vacuum salt production after drying and grinding;The particle size of the well salt gypsum is D 95 =40-50 μm.

[0011] Preferably, the A component and the B component further include water;The mass ratio of water to solid component in the A component and / or the B component is 0.6-0.7.

[0012] Preferably, the solid water reducing agent is early strength polycarboxylic acid water reducing agent.

[0013] Preferably, the mass ratio of the A component to the B component is 1:1.

[0014] Preferably, the A component and the B component are stored separately before grouting.

[0015] Beneficial effects:

[0016] (1) The two-component grouting material for coal mine roadway surrounding rock shallow hole reinforcement of the present application uses a large amount of well salt gypsum and desulfurization ash which are difficult to be recycled, and is green, energy-saving, carbon-reducing, simple in processing technology and significantly reduces production cost.

[0017] (2) In the two-component grouting material for coal mine roadway surrounding rock shallow hole reinforcement of the present application, by reasonably controlling the dosage ratio and fineness of desulfurization ash and well salt gypsum, the A component slurry and the B component slurry can maintain good fluidity and suspension stability for a long time without using additional retarder, suspending agent (or thickening agent), so as to facilitate on-site grouting construction.

[0018] (3) The salt impurities contained in the well salt gypsum in the present application can accelerate the dissolution of anhydrous calcium sulfate in the well salt gypsum, thereby accelerating the hydration reaction of the grouting material and speeding up the setting and hardening speed of the grouting material, i.e. indirectly acting as a quick-setting agent and early strength agent.

[0019] (4) The grouting material of the present application has the characteristics of good workability, fast condensation and hardening, and high early strength, which meets the needs of surrounding rock shallow hole grouting reinforcement. At the same time, compared with the prior art, the grouting material of the present application has fewer component types, significantly simplifies the production process, shortens the production cycle, improves the production efficiency and quality stability. BRIEF DESCRIPTION OF DRAWINGS

[0020] The accompanying drawings constituting a part of this application provide further understanding of the present application, the illustrative embodiments of the present application and the description thereof serve to explain the present application, and do not constitute improper limitation on the present application. Among them:

[0021] Figure 1 The roof and floor displacement change curve diagram obtained by applying the two-component grouting material for coal mine roadway surrounding rock shallow hole reinforcement provided in embodiment 1 of the present application to surrounding rock grouting reinforcement test;

[0022] Figure 2 The two-side displacement change curve diagram obtained by applying the two-component grouting material for coal mine roadway surrounding rock shallow hole reinforcement provided in embodiment 1 of the present application to surrounding rock grouting reinforcement test. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments in the present application belong to the scope of protection of the present application.

[0024] The present application will be described in detail below in combination with embodiments. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0025] In view of the problems of excessive admixture and high cost of the grouting material in the prior art, the present application provides a two-component grouting material for coal mine roadway surrounding rock shallow hole processing.

[0026] The two-component grouting material for processing shallow holes of surrounding rock of a coal mine tunnel according to the embodiment of the application comprises component A and component B. The solid components of component A comprise, in parts by mass, 80-90 parts (for example, 80 parts, 82 parts, 84 parts, 86 parts, 88 parts or 90 parts) of sulphoaluminate cement clinker, 10-20 parts (for example, 10 parts, 12 parts, 14 parts, 16 parts, 18 parts or 20 parts) of denitration ash residue and 0.1-0.3 parts (for example, 0.1 part, 0.2 part and 0.3 part) of water reducing agent. The solid components of component B comprise, in parts by mass, 64-72 parts (for example, 64 parts, 65 parts, 66 parts, 67 parts, 68 parts, 69 parts, 70 parts, 71 parts or 72 parts) of well salt gypsum, 16-18 parts (for example, 16 parts, 17 parts or 18 parts) of quicklime, 10-20 parts (for example, 10 parts, 12 parts, 14 parts, 16 parts, 18 parts or 20 parts) of denitration ash residue and 0.2-0.4 parts (for example, 0.2 part, 0.3 part and 0.4 part) of water reducing agent.

[0027] The denitration ash residue is a solid waste discharged after the SCR denitration technology is used in coal gasification, and the particle size thereof is up to 10 mm, of which the particle size of 0.15 mm or more accounts for 30-40%. The inventors have found in research that the denitration ash residue has the characteristics of large particle size, high porosity and large water demand, and is difficult to be directly utilized. However, the water demand thereof can be reduced by grinding, and the water demand varies with the degree of grinding. In addition, the water retention thereof has a certain alleviating effect on the loss of flowability of the slurry over time. If the water demand thereof can be adjusted by controlling the appropriate particle size, the workability of the slurry will be significantly improved, the dependence on the retarder, the suspending agent or the thickening agent will be reduced, and the volcanic ash effect thereof will be exerted, the performance of the grouting material will be improved, the use amount of the sulphoaluminate cement clinker, the gypsum and the quicklime will be reduced, and the production cost will be reduced.

[0028] Well salt gypsum is a kind of waste residue discharged after filtering water in the vacuum salt making of brine in well salt industry, the main component of which is anhydrous gypsum, the water content of which is about 30%, which can not condense all the year round under the condition of airtightness, and the salt content of which is high (6% to 8%), so that the gypsum or cement products need to be desalted in addition to drying, resulting in an increase in treatment cost. The inventors found in the research that the strength of well salt gypsum after drying is very low (1 MPa to 2 MPa), which is easily broken into fine powder, and is easily dispersed into particles below 10 μm after adding water, but the degree of pulverization will affect the dissociation speed, when the particle size of well salt gypsum reaches 40 μm to 50 μm, it can be quickly dissociated into tiny particles in water. When the well salt gypsum with extremely small particle size is used in the B component, the viscosity of the slurry, the suspension stability and the injectability of the slurry can be improved, and the well salt gypsum is the same as the anhydrite component, the particle size is small, and the condensation and hardening are faster; if the anhydrite is replaced, the influence of the exploitation of anhydrite on the natural environment can be reduced, and there is no need to increase the desalting process. In addition, the salt impurities contained in the well salt gypsum can also accelerate the dissolution of anhydrous calcium sulfate in the well salt gypsum, and then accelerate the hydration reaction of the grouting material and the condensation and hardening speed of the grouting material, that is, indirectly play the role of accelerators and early strength agents.

[0029] Therefore, the well salt gypsum is used to replace the anhydrite in the present application, and the denitration ash slag is used to partially replace the sulphoaluminate cement clinker, gypsum and lime, so that a green low-carbon, low-cost, two-component grouting material for shallow hole reinforcement of coal mine roadway surrounding rock can be provided without adding external agents such as thickening agent, suspending agent or retarder. At the same time, the two-component grouting material for shallow hole reinforcement of coal mine roadway surrounding rock has the characteristics of good stability and injectability, fast condensation and hardening, and high early strength. In addition, compared with the prior art, the grouting material has fewer components, the production process can be significantly simplified, the production cycle can be shortened, the production efficiency and quality stability can be improved, and the use method is simple, that is, the solid components of the A component and the B component are uniformly mixed with water, and then grouting construction is carried out (preferably, the grouting pump sucks the A component and the B component at the same grouting speed during grouting construction).

[0030] Preferably, the mass of the water reducing agent in the A component is 0.1% to 0.3% (for example, 0.1%, 0.15%, 0.2%, 0.25% or 0.3%) of the sum of the mass of the sulphoaluminate cement clinker and the denitration ash slag; the mass of the water reducing agent in the B component is 0.2% to 0.4% (for example, 0.2%, 0.25%, 0.3%, 0.35% or 0.4%) of the sum of the mass of the well salt gypsum, the quicklime and the denitration ash slag.

[0031] In the preferred embodiment of the two-component grouting material for shallow hole reinforcement of coal mine roadway surrounding rock, the denitration ash slag is a solid waste discharged after the SCR denitration technology is used after coal gasification in coal chemical industry, which is pulverized to a particle size D 95 ≤ 20 μm.

[0032] In the preferred embodiment of the two-component grouting material for reinforcing surrounding rock of a coal mine roadway, the well salt gypsum is waste slag discharged from vacuum salt production of brine, which is dried and finely ground. 95 The particle size of the well salt gypsum is D 95 By drying the well salt gypsum, agglomeration is avoided. By finely grinding the well salt gypsum into particles with a particle size of D

[0033] In the preferred embodiment of the two-component grouting material for reinforcing surrounding rock of a coal mine roadway, the water in the A component and / or the B component is mixed with the solid components in a mass ratio of 0.6-0.7 (for example, 0.6, 0.62, 0.64, 0.66, 0.68, or 0.7).

[0034] In the preferred embodiment of the two-component grouting material for reinforcing surrounding rock of a coal mine roadway, the water-reducing agent in the A component and / or the B component is an early-strength polycarboxylic acid water-reducing agent.

[0035] In the preferred embodiment of the two-component grouting material for reinforcing surrounding rock of a coal mine roadway, the mass ratio of the A component to the B component is 1:1.

[0036] In the preferred embodiment of the two-component grouting material for reinforcing surrounding rock of a coal mine roadway, the A component and the B component are stored separately before grouting.

[0037] The two-component grouting material for reinforcing surrounding rock of a coal mine roadway and the construction method thereof will be described in detail below through specific embodiments.

[0038] The sources of the main raw materials used in the following embodiments are as follows: the sulphoaluminate cement clinker, the quicklime, and the early-strength polycarboxylic acid water-reducing agent are commercially available industrial products. Specifically, the sulphoaluminate cement clinker is purchased from Tangshan Polar Bear Building Material Co., Ltd.; the quicklime is purchased from Pingdingshan Guangwen Trading Co., Ltd.; and the early-strength polycarboxylic acid water-reducing agent (solid) is purchased from Shandong Wanshan Chemical Co., Ltd. The denitrification slag is sourced from the Nylon City Industrial Park in Pingdingshan, and the well salt gypsum is sourced from China Pingmei Shenma Group Joint Salt Chemical Co., Ltd.

[0039] The chemical compositions of the well salt gypsum and the denitrification slag are shown in Tables 1-2 below:

[0040] Table 1 Chemical composition of well salt gypsum / %

[0041] Na2O MgO SiO2 [P2O5] SO3 Cl CaO SrO 0.81 0.28 0.29 0.01 52.31 0.20 45.19 0.91

[0042] Table 2 Chemical composition of desulfurized ash / %

[0043] Na2O MgO Al2O3 SiO2 P2O5 SO3 [K2O] CaO TiO2 Fe2O3 0.62 0.56 26.73 58.15 0.06 3.36 1.42 2.56 1.81 4.73

[0044] The particle size distribution of the well salt gypsum and the desulfurized ash is shown in Table 3 below:

[0045] Table 3 Particle size of well salt gypsum and desulfurized ash

[0046] Raw materials D 10 / μm D 50 / μm D 95 / μm Well salt gypsum 1.9 9.4 43.6 Denitration ash 0.8 5.7 19.4

[0047] The market prices of various raw materials are shown in Table 4 below:

[0048] Table 4 Market prices of various raw materials

[0049]

[0050] Example 1

[0051] The two-component grouting material for shallow hole reinforcement of coal mine roadway surrounding rock of the present example includes, by mass fraction:

[0052] The solid components of the A component include: 88 parts of sulphoaluminate cement clinker, 12 parts of desulfurized ash, and 0.1 part of early strength polycarboxylic acid superplasticizer;

[0053] The B component includes: 70 parts of well salt gypsum, 18 parts of quicklime powder, 12 parts of desulfurized ash, and 0.2 part of early strength polycarboxylic acid superplasticizer;

[0054] The well salt gypsum is obtained after drying at 40℃, with a water content of less than 1%, and is ground to a particle size D 95 of no more than 44 μm; the desulfurized ash used is ground to a particle size D 95 of no more than 20 μm.

[0055] The construction method of the two-component grouting material for shallow hole reinforcement of coal mine roadway surrounding rock of the present example includes the following steps:

[0056] (1) uniformly mix the solid components of the A component with water (the mass ratio of water to solid components in the A component is 0.62), and uniformly mix the solid components of the B component with water (the mass ratio of water to solid components in the B component is 0.62);

[0057] (2) mix and grout the A component and the B component (the mass ratio of the A component to the B component is 1:1) through a grouting pump and a mixer at the same suction speed.

[0058] Example 2

[0059] The two-component grouting material for shallow hole reinforcement of coal mine roadway surrounding rock of the present example includes, by mass fraction:

[0060] The solid component of the A component includes: 82 parts of sulphoaluminate cement clinker, 18 parts of denitration slag, 0.3 part of early strength polycarboxylic acid water reducer;

[0061] The solid component of the B component includes: 65 parts of well salt gypsum, 17 parts of quicklime powder, 18 parts of denitration slag, 0.4 part of early strength polycarboxylic acid water reducer;

[0062] The well salt gypsum is obtained after drying at 40℃, and the water content is less than 1%, and is ground to a particle size D 95 of no more than 44μm; the denitration slag is ground to a particle size D 95 of no more than 20μm.

[0063] The construction method of the two-component grouting material for reinforcing the surrounding rock of the coal mine tunnel in this embodiment includes the following steps:

[0064] (1) uniformly mix the solid component of the A component with water (the mass ratio of water to solid component in the A component is 0.62), and uniformly mix the solid component of the B component with water (the mass ratio of water to solid component in the B component is 0.62);

[0065] (2) mix and grout the A component and the B component (the mass ratio of the A component to the B component is 1:1) through a grouting pump and a mixer at the same grouting speed.

[0066] Example 3

[0067] The two-component grouting material for reinforcing the surrounding rock of the coal mine tunnel in this embodiment includes, by mass fraction:

[0068] The solid component of the A component includes: 88 parts of sulphoaluminate cement clinker, 12 parts of denitration slag, 0.1 part of early strength polycarboxylic acid water reducer;

[0069] The solid component of the B component includes: 70 parts of well salt gypsum, 18 parts of quicklime powder, 12 parts of denitration slag, 0.2 part of early strength polycarboxylic acid water reducer;

[0070] The well salt gypsum is obtained after drying at 40℃, and the water content is less than 1%, and is ground to a particle size D 95 of no more than 44μm. The denitration slag is ground to a particle size D 95 of no more than 20μm.

[0071] The construction method of the two-component grouting material for reinforcing the surrounding rock of the coal mine tunnel in this embodiment includes the following steps:

[0072] (1) The solid components of the A component were mixed with water (the mass ratio of water to solid components in the A component was 0.67) and the solid components of the B component were mixed with water to obtain a B slurry (the mass ratio of water to solid components in the B component was 0.67);

[0073] (2) The A component and the B component (the mass ratio of the A component to the B component was 1:1) were mixed by a grouting pump and a mixer at the same pumping speed, and then grouting was performed.

[0074] The viscosity, bleeding rate, setting time and 2h compressive strength of the two-component grouting material for reinforcing the surrounding rock of the coal mine tunnel in Examples 1-3 were tested, and the test results are shown in Table 5 below:

[0075] Table 5

[0076]

[0077] Comparative Example 1

[0078] The grouting material of the present comparative example comprises, by mass fraction:

[0079] The solid components of the A component comprise: 100 parts of sulphoaluminate cement clinker, 4 parts of a suspending agent (sodium-based bentonite), 0.1 part of a common polycarboxylic acid water reducer and 2 parts of a retarder (sodium gluconate); the mass ratio of water to solid components was 0.62;

[0080] The solid components of the B component comprise: 80 parts of hard gypsum, 20 parts of quicklime, 8 parts of a suspending agent (sodium-based bentonite) and 0.5 parts of an accelerator (lithium carbonate); the mass ratio of water to solid components was 0.62;

[0081] The performance indicators of the A component, the B component and the mixed slurry do not differ by more than 5% from those of Example 2, but the cost increases by about 360 yuan / ton.

[0082] Comparative Example 2

[0083] The grouting material of the present comparative example comprises:

[0084] The solid components of the A component: 100 parts of sulphoaluminate cement clinker and 0.1 part of an early-strength polycarboxylic acid water reducer; the mass ratio of solid components to water was the same as in Example 1;

[0085] The B component is the same as in Example 2;

[0086] The performance test results of the grouting material of the present comparative example (compared with Example 1): the 1h bleeding rate of the A component increased from 1.6% to 12.4%, the 20min flow rate increased from 47s to 75s, and the slurry lost fluidity after 30min.

[0087] Further experiments show that when 6 parts of suspending agent (sodium bentonite) and 2 parts of retarder (sodium gluconate) are added to the A component, the 1 h bleeding rate of the A component slurry is 1.8%, and the 20 min time-dependent fluidity is 50 s, which is not much different from the A slurry in Example 2, but the cost increases by about 190 yuan / ton.

[0088] Comparative Example 3

[0089] The difference between this comparative example and Example 1 is only that desulfurized gypsum (particle size D 95 49 μm) discharged by a thermal power plant is used to replace the well salt gypsum in the same amount; and the rest is consistent with Example 1.

[0090] The performance test results of the grouting material of this comparative example (compared with Example 1) are as follows: the 1 h bleeding rate of the B component slurry increases from 2.5% to 10.2%, and the particle settlement is serious; and the 2 h strength of the mixed slurry decreases from 18.9 MPa to 7.7 MPa.

[0091] Further experiments show that when 5 parts of common suspending agent (sodium bentonite) are added to the B component, the 1 h bleeding rate of the B component slurry is 2.4%, which is not much different from Example 1, but the 2 h strength of the mixed slurry is only 8.1 MPa. At the same time, the cost increases by about 20 yuan / ton.

[0092] Comparative Example 4

[0093] The difference between this comparative example and Example 1 is only that the hard gypsum used is an industrial product, and the particle size D 95 45 μm, which is used to replace the well salt gypsum in the same amount; and the rest is consistent with Example 1.

[0094] The performance test results of the grouting material of this comparative example (compared with Example 1) are as follows: the 1 h bleeding rate of the B component slurry increases from 2.5% to 12.1%, and the particle settlement is serious; and the initial setting time of the mixed slurry is extended from 12 min to 34 min, and the final setting time is extended from 14 min to 42 min.

[0095] Further experiments show that when 6 parts of common suspending agent (sodium bentonite) and 0.5 parts of accelerator (lithium carbonate) are added to the B component of this comparative example, the 1 h bleeding rate of the B component slurry is 2.7%, the initial setting time is 14 min, and the final setting time is 16 min, which are not much different from Example 1, but the cost increases by about 180 yuan / ton.

[0096] Comparative Example 5

[0097] The difference between this comparative example and Example 2 is only that the denitration ash in the B component is omitted, the amount of well salt gypsum is increased from 65 parts to 80 parts, and the amount of quicklime is increased from 17 parts to 20 parts; and the rest is consistent with Example 2.

[0098] The performance test results of the grouting material of the present comparative example (compared with Example 2): the 1h bleeding rate of the B component slurry increased from 1.3% to 3.7%; the initial setting time of the mixed slurry shortened from 13 min to 11 min, and the final setting time shortened from 15 min to 13 min.

[0099] The grouting material of the present comparative example can still meet the requirements of surrounding rock grouting reinforcement, but the cost increases by about 5 yuan / ton.

[0100] Comparative Example 6

[0101] The present comparative example differs from Example 1 only in that the particle size D 95 ≤ 65 pm, and the rest remains the same as Example 1.

[0102] The performance test results of the grouting material of the present comparative example (compared with Example 1): the initial slurry viscosity of the A component increased from 46 s to 58 s, and the initial slurry viscosity of the B component increased from 47 s to 60 s; the initial setting time of the mixed slurry extended from 12 min to 24 min, and the final setting time extended from 14 min to 28 min.

[0103] Comparative Example 7

[0104] The present comparative example differs from Example 1 only in that the particle size D 95 ≤ 80 pm after drying and powder grinding, and the rest remains the same as Example 1.

[0105] The performance test results of the grouting material of the present comparative example (compared with Example 1): the 1h bleeding rate of the B component slurry increased from 2.5% to 7.3%, and the slurry stability was poor; at the same time, the initial setting time of the mixed slurry extended from 12 min to 18 min, and the final setting time extended from 14 min to 22 min.

[0106] Comparative Example 8

[0107] The present comparative example differs from Example 1 only in that the ordinary polycarboxylic acid water reducer or the retarder type polycarboxylic acid water reducer is used instead of the early strength type polycarboxylic acid water reducer in Example 1, and the rest remains the same as Example 1.

[0108] When the ordinary polycarboxylic acid water reducer is used, the initial setting time of the mixed slurry extends from 12 min to 25 min, and the final setting time extends to 30 min; when the retarder type polycarboxylic acid water reducer is used, the initial setting time of the mixed slurry extends from 12 min to 40 min, and the final setting time extends to 50 min. These two types of water reducers cannot meet the requirements of rapid setting of shallow hole grouting of surrounding rock of roadway.

[0109] Engineering application effect analysis:

[0110] The grouting material of the embodiment 1 of the present application is used in the surrounding rock grouting reinforcement test of a mine roadway in Pingdingshan City, and the cross method is used to detect the deformation of the roof and floor and two sides of the roadway, and the interval between each measuring point is 3m. After 60d, the maximum convergence of the roof and floor of the un-reinforced section is 110mm, and the maximum convergence of the two sides is 95mm, while the convergence of the reinforced section is as shown in Table 1-5 (1#-5# in the table respectively refer to different measuring points), the maximum displacement of the roof and floor is only 12mm, and the maximum displacement of the two sides is only 10mm, which is far less than the control design index (the displacement of the roof and floor <70mm, and the displacement of the two sides <60mm), and the reinforcement effect is good. Figure 1 Figure 1

[0111] In summary, the two-component grouting material for the surrounding rock shallow hole reinforcement of the mine roadway has good slurry stability, good working performance, fast hardening and setting, and high early strength, and can meet the demand of the surrounding rock shallow hole grouting reinforcement. The present application can effectively solve the problems and deficiencies of the prior art, such as large amount of external additive, multiple types, poor product performance stability, etc., and can effectively realize the resource utilization of solid waste denitration ash and well salt gypsum.​​

Claims

1. A two-component grouting material for shallow hole reinforcement of surrounding rock of coal mine tunnel, characterized in that: The grouting material includes component A and component B; the solid components of component A include, by mass, 80-90 parts of sulphoaluminate cement clinker, 10-20 parts of denitrification ash, and 0.1-0.3 parts of a water reducer; The solid components of the B component include: 64-72 parts of well salt gypsum, 16-18 parts of quicklime, 10-20 parts of denitrification ash and 0.2-0.4 parts of water reducing agent.

2. The two-component grouting material for shallow hole reinforcement of coal mine tunnel surrounding rock according to claim 1, characterized in that: The denitrification ash is the solid waste discharged by coal chemical industry after coal gasification using SCR denitrification technology, which is ground into particles with a particle size of D 95 ≤20μm.

3. The two-component grouting material for shallow hole reinforcement of coal mine tunnel surrounding rock according to claim 1, characterized in that: The well salt gypsum is the waste residue discharged from vacuum salt production with brine, which is dried and ground; The particle size of the well salt gypsum is D 95 =40-50μm.

4. The two-component grouting material for shallow hole reinforcement of coal mine tunnel surrounding rock according to claim 1, characterized in that: The A component and the B component also include water; The mass ratio of water to solid components in the component A and / or component B is 0.6-0.

7.

5. The two-component grouting material for shallow hole reinforcement of coal mine tunnel surrounding rock according to claim 1, characterized in that: The water reducer in component A and / or component B is an early-strength polycarboxylate water reducer.

6. The two-component grouting material for shallow hole reinforcement of surrounding rock of coal mine tunnel according to any one of claims 1 to 5, characterized in that: The mass ratio of the component A to the component B is 1:1.

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