A highly thixotropic and highly adhesive cement-based anchoring material for full anchoring in argillaceous soft rock

Abstract

The present invention discloses a cement-based anchoring material with high thixotropy and high adhesion for full anchoring in argillaceous soft rock, belonging to the technical field of mining materials. The material components include: cementitious materials, admixtures, quartz sand and water, wherein the mass ratio of the cementitious materials, admixtures, quartz sand and water is 100:2.93:100:29; the cementitious materials include: portland cement, sulfoaluminate cement, mineral powder, silica fume, UEA expansive agent; the admixtures include: water reducer, plastic expansive agent, hydroxypropyl methylcellulose, polyacrylamide, fumed silica, lithium carbonate, calcium formate, defoamer, redispersible latex powder, 801 glue powder, silane coupling agent. It has good plasticity, good thixotropy, high water retention and adhesion, strong adhesion and anchoring force with the shale interface. Its good thixotropy enables no slurry leakage during roof grouting, and at the same time has water retention and high adhesion to the shale interface, thus greatly improving the anchoring force between the material and the shale.

Description

Technical Field

[0001] The present invention belongs to the technical field of mining materials, and particularly relates to a cement-based anchoring material with high thixotropy and high adhesion for full anchoring of argillaceous soft rock. Technical Background

[0002] With the increase of mining depth, the probability of engineering problems such as soft rock, strong mining disturbance, and large deformation in coal mine roadways has increased significantly. Problems such as the breakage of bolt cables and the debonding of anchoring have occurred, becoming difficult problems that need to be solved urgently in coal mine support safety. In order to reduce the damage after deep well soft rock excavation and timely control the surrounding rock deformation, support technologies with strong initial support, rapid resistance increase, and high resistance are required to prevent excessive damage and deformation of the surrounding rock. However, traditional end anchoring support has problems of insufficient adaptability under such engineering conditions. Compared with end anchoring, the full-length anchoring technology has more advantages and can effectively improve the reliability of the anchoring system, which is an effective way to solve the debonding failure problem. The bonding material within the length range of the bolt connects the surrounding rock and the bolt into a whole, enabling the bolt to not only have a holding force but also have the ability to resist the shear action of the surrounding rock within the full length, enhancing the control ability of the surrounding rock deformation.

[0003] The main way to achieve full-length anchoring of cable bolts is to first use resin anchoring agents for end anchoring and then use hollow or reserved pipes to pour anchoring materials to achieve hole filling and bonding anchoring. Cement-based grouting anchoring materials have significant advantages of low cost compared with chemical-based anchoring materials, but there are still problems such as easy slurry leakage, low stone formation rate, large shrinkage rate, and poor bonding performance, resulting in insufficient anchoring length in the free section and the appearance of anchoring bonding cavities, severely reducing the full-anchoring performance of cement-based materials. For this, Chinese Patent CN 115385615 B discloses a "Cement-based Grouting Material", which includes a cementitious material, anhydrite, quartz sand, defoamer, water reducer, and plastic expansion agent. This material solves the problem of easy shrinkage of cement grouting materials due to insufficient expansion and strength, but the fluidity of the grout is relatively large and the thixotropy is relatively low, and there is still a problem of slurry leakage in roof support. Chinese Patent CN 116514460 B discloses a "Quick-Setting Grouting Material for Structural Reinforcement", which contains the following components: slag micro-powder, fly ash, quartz powder, microsilica, steel fiber, nickel iron slag micro-powder, alkaline activator, surfactant, water reducer, retarder, and water. Through the distribution of steel fibers and nickel iron micro-powders in the "quasi-crystal" stacking structure composed of circular molecular chains, the thixotropy of the material is increased, but the water retention and bonding performance of this material are poor, and the bonding and anchoring performance with mudstone is still insufficient. Summary of the Invention

[0004] Aiming at the deficiencies of the existing technology, a cement-based anchoring material with high thixotropy and high bonding for full anchoring of argillaceous soft rock is provided. It has good plasticity, good thixotropy, high water retention and bonding properties, strong bonding and anchoring force with the shale interface, and at the same time has the characteristics of slight expansion and high early strength, and is especially suitable for the full-length anchoring of hollow anchor cables in argillaceous surrounding rock. The good thixotropy enables no leakage of grout during roof grouting, and at the same time has water retention and high bonding property with the shale interface, thus greatly improving the anchoring force between the material and the shale.

[0005] To achieve the above technical objectives, a cement-based anchoring material with high thixotropy and high bonding for full anchoring of argillaceous soft rock according to the present invention, the material components include: cementitious materials, admixtures, quartz sand and water, and the mass ratio of the cementitious materials, admixtures, quartz sand and water is 100:2.93:100:29;

[0006] The cementitious materials include: Portland cement with a mass percentage of 51-57%, sulphoaluminate cement with a mass percentage of 13-17%, blast furnace slag powder with a mass percentage of 12-20%, silica fume with a mass percentage of 3-8%, and UEA expansive agent with a mass percentage of 4-7%; the sum of the mass percentages of the raw materials in the cementitious materials is 100%;

[0007] The admixtures include: water reducer with a mass percentage of 38-45%, plastic expansive agent with a mass percentage of 1.5-3%, hydroxypropyl methylcellulose with a mass percentage of 0.7-1.2%, polyacrylamide with a mass percentage of 0.4-0.7%, fumed silica with a mass percentage of 1-2%, lithium carbonate with a mass percentage of 1-3%, calcium formate with a mass percentage of 2-4%, defoamer with a mass percentage of 7-11%, redispersible latex powder with a mass percentage of 32-42%, 801 rubber powder with a mass percentage of 3-5%, and silane coupling agent with a mass percentage of 3-5%; the sum of the mass percentages of the raw materials in the admixtures is 100%.

[0008] Both the Portland cement and the sulphoaluminate cement are of grade 42.5, and the specific surface area ≥ 400m 2 / kg; the blast furnace slag powder is S95 grade blast furnace slag powder; the SiO2 content of the silica fume is 96%; the fineness of the quartz sand is 70-110 mesh; the water reducer is a high-performance polycarboxylate water reducer, and the water reduction rate ≥ 35%.

[0009] Furthermore, in the UEA expansive agent, the proportion of aluminium sulphate and alumina is not less than 70%, and the specific surface area ≥ 200m 2 / kg.

[0010] Furthermore, it is characterized in that the average particle size of the plastic expansive agent is 2.5-3.9μm, and the foaming time ≤ 12h.

[0011] Furthermore, the viscosity of the hydroxypropyl methylcellulose is 400 Pa·s, and the purity is industrial grade.

[0012] Furthermore, the polyacrylamide is PAM anionic type 1200.

[0013] Furthermore, the fumed silica is composed of fumed silica with particle sizes of 20 nm and 1 μm in a mass ratio of 2:1, and the purity of both is 99.9%.

[0014] Furthermore, the redispersible latex powder is vinyl acetate / ethylene copolymer powder, with a solids content of ≥99% and a particle size of 1 - 7 μm.

[0015] Furthermore, the silane coupling agent is γ-aminopropyltriethoxysilane.

[0016] A preparation method of a high thixotropic and high bonding cement-based anchoring material for full anchoring of argillaceous soft rock is as follows:

[0017] (1) Put the silane coupling agent into water according to the material ratio, and stir at a low speed for 3 - 5 min, with the stirring temperature being 15 - 35°C;

[0018] (2) Put the gelling material, other admixtures, and quartz sand into the mixer in sequence according to the material ratio, stir at a low speed for 1 - 2 min, add 80% of the water by mass ratio, stir at a high speed for 1 - 2 min, add the remaining water, and continue to stir at a high speed for 3 - 5 min to obtain the anchoring material; the rotation speed of the low-speed stirring is 120 - 180 r / min; the rotation speed of the high-speed stirring is 250 - 350 r / min.

[0019] Beneficial effects: Compared with the existing anchoring materials, the high thixotropic and high bonding cement-based anchoring material of the present invention has the following beneficial effects:

[0020] 1) The performance of the grout of the present invention is stable and controllable. The grout has no segregation and bleeding, and the performance is uniform. The initial setting time of the grout can be adjusted within 95 min - 230 min, and the fluidity of the grout can be adjusted within 260 - 310 mm, which can meet the application requirements of various engineering conditions. At the same time, through the compounding of sulfoaluminate cement and early strength agent, the strength of the grout develops rapidly after initial setting. The 1-day compressive strength is ≥30 MPa; the long-term strength of the stone body is large, the 28-day compressive strength is ≥80 MPa, the flexural strength is ≥20 MPa, the bearing capacity of the stone body is strong, the ratio of flexure to compression is large, and the grout has outstanding bending and flexural resistance, which can greatly improve the anti-rock layer dislocation and shear ability of the full-anchoring structure.

[0021] 2) Through the low-dosage compounding of hydroxypropyl methylcellulose, polyacrylamide, and fumed silica, the present invention can form an organic-inorganic hybrid adsorption crosslinking network within the system, significantly enhancing the water retention, plasticity, and cohesion of the grout material, thereby remarkably improving the thixotropy of the grout material. Meanwhile, by combining with a high-performance polycarboxylate water reducer and a plasticizing expansive agent, lubrication between particles and foaming can be achieved, enabling the grout material to have good fluidity during pumping, reducing the pumping resistance, having strong pumpability, and having a stable thixotropy after being pumped into the borehole, meeting the requirements of stopping the grout when the pump stops and the grout not flowing out after pressure release, and enabling precise quantitative and fixed-length anchoring within the borehole.

[0022] 3) Through the compounding of redispersible latex powder and 801 rubber powder, the present invention enables a water-soluble adhesive polymer to coat the surface of the cementitious material. And through the bridging effect of the pre-dissolved silane coupling agent at the inorganic-organic interface, the bonding force between the cementitious material particles and the polymer is enhanced, further strengthening the bonding force between the material and the interface. Moreover, through the water retention provided by hydroxypropyl methylcellulose, polyacrylamide, and fumed silica, the absorption of water in the slurry by the mudstone is significantly reduced, enabling the grout material to have good bonding force with the interface of the argillaceous rock mass. The bonding strength with the mudstone is ≥2.5 MPa, and the reduction in bonding force at the wet and water-containing interface is less, with the reduction in bonding strength in the water-containing state of the interface not exceeding 10%, capable of meeting the full-length anchoring of anchor cables under various working conditions.

[0023] 4) Through the compounding of sulfoaluminate cement, UEA expansive agent, and plasticizing expansive agent, the grout material exhibits significant expansion performance in the early-middle-late stages of gelation, capable of achieving long-term (>28 days) micro-expansion with an expansion rate ≥0.2%. The long-term expansion of the slurry can generate expansion extrusion on the inner wall of the surrounding rock borehole, thereby enhancing the normal friction force of the anchoring material in the hole and further improving the bonding and anchoring performance of the grout material.

[0024] 5) The present invention mainly uses cement and quartz sand, with the grout material having a low cost and being able to replace high-cost chemical resin anchoring materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is the thixotropic flow chart of the high-thixotropy and high-bonding cement-based anchoring material for full anchoring in argillaceous soft rock in the embodiment of the present invention;

[0026] Figure 2 It is the consolidation expansion diagram of the high-thixotropy and high-bonding cement-based anchoring material for full anchoring in argillaceous soft rock in the embodiment of the present invention;

[0027] Figure 3 It is the tensile bonding test diagram of the high-thixotropy and high-bonding cement-based anchoring material for full anchoring in argillaceous soft rock in the embodiment of the present invention and the mudstone; in the figure, (a) is the state before the tensile bonding test, and (b) is the state after the tensile bonding test;

[0028] Figure 4 It is the microscopic structure diagram of the adsorption cross-linking network of the high thixotropic and high bonding cement-based anchoring material for full anchoring in argillaceous soft rock in the embodiment of the present invention;

[0029] Figure 5 It is the schematic diagram of the microscopic structure of foaming between particles of the stone body of the high thixotropic and high bonding cement-based anchoring material for full anchoring in argillaceous soft rock in the embodiment of the present invention;

[0030] Figure 6 It is the microscopic structure diagram of the slurry-rock interface between the high thixotropic and high bonding cement-based anchoring material for full anchoring in argillaceous soft rock and mudstone in the embodiment of the present invention. Specific embodiments

[0031] The embodiments of the present invention will be further described below with reference to the accompanying drawings:

[0032] Embodiment 1

[0033] A high thixotropic and high bonding cement-based anchoring material for full anchoring in argillaceous soft rock is composed of a gelling material, an admixture, quartz sand and water with a mass ratio of 100:2.93:100:29.

[0034] The gelling material includes: 570 g of Portland cement, 170 g of sulfoaluminate cement, 160 g of mineral powder, 50 g of silica fume, and 50 g of UEA expansive agent; the admixture includes: 12.89 g of water reducer, 0.59 g of plastic expansive agent, 0.35 g of hydroxypropyl methylcellulose, 0.15 g of polyacrylamide, 0.32 g of fumed silica, 0.59 g of lithium carbonate, 0.64 g of calcium formate, 2.34 of defoamer, 9.38 g of redispersible latex powder, 0.88 g of 801 rubber powder, and 1.17 g of silane coupling agent; 1000 g of quartz sand; 290 g of water.

[0035] Both the Portland cement and the sulfoaluminate cement are of grade 42.5, and the specific surface area ≥ 400 m 2 / kg; the mineral powder is S95 grade mineral powder; the SiO2 content of the silica fume is 96%; the fineness of the quartz sand is 70 - 110 mesh; the water reducer is a high-performance polycarboxylate water reducer, and the water reduction rate ≥ 35%. In the UEA expansive agent, the specific gravity of aluminum sulfate and alumina is not less than 70%, and the specific surface area ≥ 200 m 2 / kg. The average particle size of the plastic expansive agent is 2.5 - 3.9 μm, and the foaming time ≤ 12 h. The viscosity of the hydroxypropyl methylcellulose is 400 Pa·s, and the purity is industrial grade. The polyacrylamide is PAM anionic type 1200. The fumed silica is composed of fumed silica with particle sizes of 20 nm and 1 μm in a mass ratio of 2:1, and the purity of both is 99.9%. The redispersible latex powder is vinyl acetate / ethylene copolymer rubber powder, the solid content ≥ 99%, and the particle size is 1 - 7 μm. The silane coupling agent is γ-aminopropyltriethoxysilane.

[0036] A preparation method of a high thixotropic and high adhesive cement-based anchoring material for full anchoring in argillaceous soft rock, comprising the following steps:

[0037] (1) Put the silane coupling agent into water according to the material ratio, stir at low speed for 5 min, and the stirring temperature is 35 °C;

[0038] (2) Put the gelling material, other admixtures and quartz sand into the mixer in sequence according to the material ratio, stir at low speed for 1 - 2 min, add 80% of the water by mass ratio, stir at high speed for 2 min, add the remaining water, and continue to stir at high speed for 5 min to obtain the anchoring material; the rotation speed of the low-speed stirring is 180 r / min; the rotation speed of the high-speed stirring is 350 r / min.

[0039] Example 2

[0040] A high thixotropic and high adhesive cement-based anchoring material for full anchoring in argillaceous soft rock is composed of a gelling material, an admixture, quartz sand and water in a mass ratio of 100:2.93:100:29.

[0041] The gelling material includes: 550 g of portland cement, 130 g of sulfoaluminate cement, 200 g of mineral powder, 60 g of silica fume, 60 g of UEA expansive agent; the admixture includes: 12.31 g of water reducer, 0.88 g of plasticizing expansive agent, 0.29 g of hydroxypropyl methylcellulose, 0.21 g of polyacrylamide, 0.38 g of fumed silica, 0.29 g of lithium carbonate, 0.88 g of calcium formate, 2.64 of defoamer, 9.38 g of redispersible latex powder, 0.88 g of 801 rubber powder, 1.17 g of silane coupling agent; 1000 g of quartz sand; 290 g of water. The materials used are the same as those in Example 1.

[0042] A preparation method of a high thixotropic and high adhesive cement-based anchoring material for full anchoring in argillaceous soft rock, comprising the following steps:

[0043] (1) Put the silane coupling agent into water according to the material ratio, stir at low speed for 3 - 5 min, and the stirring temperature is 15 - 35 °C;

[0044] (2) Put the gelling material, other admixtures and quartz sand into the mixer in sequence according to the material ratio, stir at low speed for 1 - 2 min, add 80% of the water by mass ratio, stir at high speed for 1 - 2 min, add the remaining water, and continue to stir at high speed for 3 - 5 min to obtain the anchoring material; the rotation speed of the low-speed stirring is 120 - 180 r / min; the rotation speed of the high-speed stirring is 250 - 350 r / min.

[0045] Example 3

[0046] A high thixotropic and high bonding cement - based anchoring material for full - anchoring in argillaceous soft rock, which is composed of a cementitious material, an admixture, quartz sand and water with a mass ratio of 100:2.93:100:29.

[0047] The cementitious material includes: 530 g of portland cement, 170 g of sulfoaluminate cement, 180 g of mineral powder, 80 g of silica fume, 40 g of UEA expansive agent; The admixture includes: 11.72 g of water - reducing agent, 0.44 g of plasticizing expansive agent, 0.21 g of hydroxypropyl methylcellulose, 0.21 g of polyacrylamide, 0.32 g of fumed silica, 0.29 g of lithium carbonate, 0.88 g of calcium formate, 2.64 of defoamer, 10.55 g of redispersible latex powder, 1.17 g of 801 rubber powder, 0.88 g of silane coupling agent; 1000 g of quartz sand; 290 g of water. The materials used are the same as those in Example 1.

[0048] A preparation method of a high thixotropic and high bonding cement - based anchoring material for full - anchoring in argillaceous soft rock, which includes the following steps,

[0049] (1) Put the silane coupling agent into water according to the material ratio, stir at a low speed for 3 - 5 min, and the stirring temperature is 15 - 35 °C;

[0050] (2) Put the cementitious material, other admixtures and quartz sand into the mixer in sequence according to the material ratio, stir at a low speed for 1 - 2 min and add 80% of the water by mass, stir at a high speed for 1 - 2 min and add the remaining water, and continue to stir at a high speed for 3 - 5 min to obtain the anchoring material; The rotation speed of the low - speed stirring is 120 - 180 r / min; The rotation speed of the high - speed stirring is 250 - 350 r / min.

[0051] Example 4

[0052] A high thixotropic and high bonding cement - based anchoring material for full - anchoring in argillaceous soft rock, which is composed of a cementitious material, an admixture, quartz sand and water with a mass ratio of 100:2.93:100:29.

[0053] The cementitious material includes: 510 g of portland cement, 170 g of sulfoaluminate cement, 200 g of mineral powder, 60 g of silica fume, 60 g of UEA expansive agent; The admixture includes: 11.13 g of water - reducing agent, 0.59 g of plasticizing expansive agent, 0.29 g of hydroxypropyl methylcellulose, 0.18 g of polyacrylamide, 0.41 g of fumed silica, 0.47 g of lithium carbonate, 0.41 g of calcium formate, 2.05 of defoamer, 11.43 g of redispersible latex powder, 1.47 g of 801 rubber powder, 0.88 g of silane coupling agent; 1000 g of quartz sand; 290 g of water. The materials used are the same as those in Example 1.

[0054] A preparation method of a high thixotropic and high bonding cement - based anchoring material for full - anchoring in argillaceous soft rock, which includes the following steps,

[0055] (1) Put the silane coupling agent into water according to the material ratio, stir at a low speed for 3 - 5 min, and the stirring temperature is 15 - 35 °C;

[0056] (2) Put the cementitious material, other admixtures and quartz sand into the mixer in sequence according to the material ratio, stir at a low speed for 1 - 2 min, add 80% of the water by mass ratio, stir at a high speed for 1 - 2 min, add the remaining water, and continue to stir at a high speed for 3 - 5 min to obtain the anchoring material; the rotation speed of the low-speed stirring is 120 - 180 r / min; the rotation speed of the high-speed stirring is 250 - 350 r / min.

[0057] The relevant properties of the above embodiments were tested through the slump flow test, the water absorption test of the slurry and mudstone, the thixotropy test of the slurry, the vertical expansion rate test of the stone body, the tensile bond test, the 1-day compressive strength test, the 3-day compressive strength test and the 28-day compressive strength test.

[0058] After testing, the test results of Examples 1 - 4 are shown in Table 1. It can be seen from the table that within the mixing ratio range, the properties of the grouting material are stable and the performance is uniform. The slump flow is between 313 - 324 mm; the water absorption between the slurry and mudstone is small, between 0.05 - 0.09%; the thixotropy coefficient is high and stable, between 2.42 - 2.63, indicating that the material has good thixotropy, as Figure 1 shown; the expansion rate is relatively stable, between 0.51 - 0.75%, and has the characteristic of long-term micro-expansion, as Figure 2 shown; through the tensile bond experiment, as Figure 3 in (a) and (b), it can be seen that the bond strength between the slurry and mudstone is relatively large, 2.84 - 2.99 MPa; the early strength of the material is relatively high, the final strength is large, and the strength development is fast. The 1-day compressive strength is 25.3 - 28.4 MPa, the 3-day compressive strength is 37.4 - 41.4 MPa, and the 28-day strength is 61.5 - 65.1 MPa. This is because through the low-dosage compounding of hydroxypropyl methylcellulose, polyacrylamide and fumed silica in the present invention, an organic-inorganic hybrid adsorption cross-linked network can be formed in the system (see Figure 3 ), which greatly improves the water retention, plasticity and cohesiveness of the grouting material, thus significantly improving the thixotropy of the grouting material. At the same time, by matching with a high-performance polycarboxylate water reducer and a plastic expansion agent, lubrication and foaming between particles are realized, as Figure 4As shown, it can make the grouting material have good fluidity during pumping, reduce the pumping resistance, have strong pumpability, and have stable thixotropy after being pumped into the borehole. It can meet the requirements of stopping the slurry when the pump stops and the slurry not flowing out after the pressure is released, and can achieve accurate quantitative and fixed-length anchoring in the borehole. Through the compounding of redispersible latex powder and 801 rubber powder, a water-soluble adhesive polymer is coated on the surface of the cementitious material, and through the bridging action of the pre-dissolved silane coupling agent at the inorganic-organic interface, the bonding force between the cementitious material particles and the polymer is enhanced, and further the bonding force between the material and the interface is enhanced. And through the water retention provided by hydroxypropyl methylcellulose, polyacrylamide, and fumed silica, the absorption of water in the slurry by the mudstone is greatly reduced, and the interface bonding is dense and firm. See Figure 5 , making the grouting material have good bonding force with the interface of the argillaceous rock mass. The bonding strength with mudstone is ≥2.5 MPa, and the bonding force decreases less at the wet and water-containing interface. The bonding strength at the water-containing state of the interface decreases by no more than 10%, which can meet the full-length anchoring of anchor cables under various working conditions. Through the compounding of sulfoaluminate cement, UEA expansive agent, and plastic expansive agent, the grouting material has significant expansion performance in the early-middle-late stages of gelation, can achieve long-term (>28 days) micro-expansion, and the expansion rate is ≥0.2%. The long-term expansion of the slurry can produce expansion extrusion on the inner wall of the surrounding rock borehole, thereby enhancing the normal friction force of the anchoring material in the hole and further improving the bonding and anchoring performance of the grouting material. Figure 6 It is a microstructural diagram of the slurry-rock interface between a cement-based anchoring material with high thixotropy and high bonding for full anchoring in argillaceous soft rock and mudstone.

[0059] Table 1 Test results of Examples 1-4

[0060] Flowability / mm Water Absorption / % Thixotropy Coefficient Swelling Ratio / % Bond Strength / MPa 1-day Compressive Strength / MPa 3-day Compressive Strength / MPa 28-day Compressive Strength / MPa Example 1 315 0.08 2.54 0.68 2.84 26.5 38.9 64.2 Example 2 324 0.09 2.63 0.75 2.86 25.6 37.9 65.1 Example 3 317 0.06 2.42 0.51 2.95 28.4 41.4 61.5 Example 4 313 0.05 2.51 0.62 2.99 25.3 37.4 63.7

[0061] Comparative Example 1

[0062] Same as Example 1, the difference is only that one of hydroxypropyl methylcellulose, polyacrylamide, fumed silica, redispersible latex powder, 801 rubber powder, silane coupling agent, UEA expansive agent, and plastic expansive agent is removed from the material ratio, and other parameters are the same as those in Example 1 and will not be elaborated. The test results are shown in Table 2 below.

[0063] As can be seen from Table 2 in combination with the data of Example 1, when a certain component in the anchoring material is removed, it will have a significant impact on the overall performance of the material. Among them, after removing hydroxypropyl methylcellulose, the cohesiveness of the grout decreases, the fluidity increases, the water absorption rate increases significantly, the thixotropy coefficient and the bonding strength decrease significantly, the compressive strength increases, and the impact on the expansion rate is relatively small; after removing polyacrylamide, the impact characteristics on the slurry are similar to those of hydroxypropyl methylcellulose, but the impact degree is slightly weaker; after removing fumed silica, the fluidity of the grout increases significantly, the thixotropy coefficient decreases significantly, and the impact on other parameters is relatively small; after removing redispersible latex powder, the fluidity of the slurry increases, the thixotropy coefficient decreases, the bonding strength decreases significantly, the compressive strength increases more, the impact on the bonding strength is the greatest, and the impact on other parameters is relatively small; after removing 801 rubber powder, the impact characteristics on the slurry are similar to those of redispersible latex powder, but the impact degree is slightly weaker; after removing silane coupling agent, the impact on the bonding strength of the slurry is relatively large, and the impact on other parameters is relatively small; after removing UEA expansive agent, the impact on the overall expansion rate of the slurry is relatively large, the strength is slightly increased, and the impact on other parameters is relatively small; after removing plastic expansive agent, the fluidity and thixotropy coefficient of the slurry decrease, the strength increases, and the impact on other parameters is relatively small. From the above analysis, it can be known that the impact on the fluidity of the slurry is: hydroxypropyl methylcellulose > fumed silica > polyacrylamide > redispersible latex powder > 801 rubber powder > plastic expansive agent > UEA expansive agent > silane coupling agent; the impact on the water absorption rate of the slurry and mudstone is: hydroxypropyl methylcellulose > polyacrylamide > redispersible latex powder > 801 rubber powder > silane coupling agent > fumed silica > plastic expansive agent > UEA expansive agent; the impact on the thixotropy coefficient of the slurry is: fumed silica > hydroxypropyl methylcellulose > polyacrylamide > redispersible latex powder > 801 rubber powder > plastic expansive agent > UEA expansive agent > silane coupling agent; the impact on the expansion rate of the slurry is: plastic expansive agent > UEA expansive agent > polyacrylamide > redispersible latex powder > hydroxypropyl methylcellulose > 801 rubber powder > fumed silica > silane coupling agent; the impact on the bonding strength of the slurry is: redispersible latex powder > hydroxypropyl methylcellulose > 801 rubber powder > polyacrylamide > silane coupling agent > fumed silica > plastic expansive agent > UEA expansive agent; the impact on the early compressive strength of the grout stone body is: plastic expansive agent > hydroxypropyl methylcellulose > UEA expansive agent > redispersible latex powder > polyacrylamide > 801 rubber powder > fumed silica > silane coupling agent; the impact on the ultimate strength of the grout stone body is: plastic expansive agent > redispersible latex powder > 801 rubber powder > hydroxypropyl methylcellulose > UEA expansive agent > polyacrylamide > silane coupling agent > fumed silica. Based on the above analysis, it can be known that when a certain component in the cement-based anchoring material is removed, it will have an adverse impact on a certain performance of the anchoring material, and none of the above materials can be missing.

[0064] Table 2 Influence of Removing a Certain Component on Performance

[0065] Flowability / mm Water Absorption / % Thixotropy Coefficient Swelling Ratio / % Bond Strength / MPa 1-day Compressive Strength / MPa 3-day Compressive Strength / MPa 28-day Compressive Strength / MPa Example 1 315 0.08 2.54 0.68 2.84 26.5 38.9 64.2 Hydroxypropyl Methylcellulose 390 0.48 1.49 0.63 1.75 29.8 43.7 73.1 Polyacrylamide 377 0.21 1.84 0.62 1.96 28.4 41.8 67.5 Fumed Silica 386 0.07 0.89 0.67 2.51 27.4 37.9 64.7 Redispersible Polymer Powder 347 0.1 2.06 0.63 1.21 28.9 42.9 75.8 801 Glue Powder 332 0.1 2.1 0.66 1.93 28.2 41.5 73.7 Silane Coupling Agent 312 0.09 2.5 0.68 2.12 27.4 37.2 65.8 UEA Expansive Agent 318 0.04 2.45 0.58 2.8 29.2 42.9 72.3 Plastic Expansive Agent 293 0.05 2.16 0.11 2.75 32.7 45.9 75.9

[0066] Comparative Example 2

[0067] Same as Example 1, the difference is only that in the slurry preparation method, the silane coupling agent is stirred synchronously with other materials without pre-hydrolyzing it in water. The other materials and steps are the same as those in Example 1 and will not be elaborated here. The test results are shown in Table 3 below.

[0068] Table 3 Influence of non-pre-hydrolysis of silane coupling agent on slurry properties

[0069] Flowability / mm Water Absorption / % Thixotropy Coefficient Swelling Ratio / % Bond Strength / MPa 1-day Compressive Strength / MPa 3-day Compressive Strength / MPa 28-day Compressive Strength / MPa Example 1 315 0.08 2.54 0.68 2.84 26.5 38.9 64.2 Comparative Example 2 319 0.09 2.5 0.63 2.18 27.8 37.2 64.8

[0070] As can be seen from the above table, in the slurry preparation method, after the silane coupling agent is stirred synchronously with other materials, the bonding strength of the prepared slurry to the mudstone is significantly reduced. Because by pre-adding it to water and stirring within a specified temperature, it can accelerate the hydrolysis of the silane coupling agent into short-chain small molecule structures, realize the structural change of the silane coupling agent molecules, and promote the cross-linking combination between the inorganic particles and the surface of the polymer network, thereby improving the bonding performance of the cement-polymer system at the mudstone interface. Therefore, the silane coupling agent should be pre-added to water and stirred for hydrolysis.

[0071] Comparative Example 3

[0072] Chinese Patent CN 115385615 B "A Cement-based Grouting Material" consists of the following raw materials: cementitious materials, anhydrite, quartz sand, defoamer, water reducer, retarder, and plastic expansion agent; the dosage of the defoamer is 0.2% of the cementitious materials, the dosage of the water reducer is 0.15% of the cementitious materials, the dosage of the plastic expansion agent is 0.3% of the cementitious materials, the cementitious materials are sulfoaluminate cement and 42.5R cement, the dosage of the sulfoaluminate cement is less than 10% of the cementitious materials, the dosage of the anhydrite is less than 5% of the cementitious materials, the dosage of the retarder is 0.24% of the cementitious materials, the retarder is a combination of sodium gluconate and tartaric acid, and the dosage ratio of sodium gluconate to tartaric acid is 3:5. The water-cement ratio is 0.23.

[0073] After testing, the performance comparison between Example 1 and Comparative Example 3 is shown in Table 4. As can be seen from Table 4, compared with Example 1, the slump flow of Comparative Example 3 is too large, being 417 mm, the thixotropy is poor, and the thixotropy coefficient is 1.1, which cannot meet the pumping thixotropic construction of the pumping type anchoring material. At the same time, the water absorption rate at the mudstone interface increases significantly, rising to 0.58%, and the bonding strength between the mudstones is relatively low, being 1.5 MPa. Although the compressive strength of the stone body of Comparative Example 3 is relatively large, the anchoring material mainly acts by bonding force in the drill hole. Therefore, the excessive compressive strength cannot play a role, and Comparative Example 3 cannot meet the technical requirements of the pumping anchoring technology for argillaceous surrounding rock.

[0074] Table 4 Performance Comparison between Example 1 and Comparative Example 3

[0075] Flowability / mm Water Absorption / % Thixotropy Coefficient Swelling Ratio / % Bond Strength / MPa 1-day Compressive Strength / MPa 3-day Compressive Strength / MPa 28-day Compressive Strength / MPa Example 1 315 0.08 2.54 0.68 2.84 26.5 38.9 64.2 Comparative Example 3 417 0.58 1.1 0.32 1.5 39.6 58.3 95.4

Claims

1. A high thixotropic and high bonding cement-based anchoring material for full anchoring of muddy soft rock, characterized in that: The material components include: cementitious material, admixture, quartz sand and water, wherein the mass ratio of cementitious material, admixture, quartz sand and water is 100:2.93:100:29; The cementitious material includes: 51-57% by mass of silicate cement, 13-17% by mass of sulphoaluminate cement, 12-20% by mass of mineral powder, 3-8% by mass of silica fume, and 4-7% of UEA expansion agent; the total mass percentage of each raw material in the cementitious material is 100%; The admixtures include: 38-45% by mass of water reducing agent, 1.5-3% by mass of plastic expansion agent, 0.7-1.2% by mass of hydroxypropyl methylcellulose, 0.4-0.7% by mass of polyacrylamide, 1-2% by mass of fumed silica, 1-3% by mass of lithium carbonate, 2-4% by mass of calcium formate, 7-11% by mass of defoaming agent, 32-42% by mass of dispersible latex powder, 3-5% by mass of 801 rubber powder, and 3-5% by mass of silane coupling agent; the total mass percentage of each raw material in the admixture is 100%; The silicate cement and sulphoaluminate cement are both grade 42.5, with a specific surface area of ​​≥400m 2 / kg; the mineral powder is S95 grade mineral powder; the SiO2 content of the silica fume is 96%; the fineness of the quartz sand is 70-110 mesh; the water reducer is a high-performance polycarboxylate water reducer, and the water reduction rate is ≥35%; The preparation method steps are as follows: (1) Put the silane coupling agent into water according to the material ratio, stir at low speed for 3-5 minutes, and the stirring temperature is 15-35℃; (2) Put the cementitious material, other admixtures and quartz sand into the mixer in sequence according to the material ratio, stir at a low speed for 1-2 minutes, add 80% water by mass, stir at a high speed for 1-2 minutes, add the remaining water, and continue stirring at a high speed for 3-5 minutes to obtain the anchoring material; the rotation speed of the low-speed stirring is 120-180 r / min; the rotation speed of the high-speed stirring is 250-350 r / min.

2. The high thixotropic and high bonding cement-based anchoring material for full anchoring of muddy soft rock according to claim 1, characterized in that: The proportion of aluminum sulfate and aluminum oxide in the UEA expansion agent is not less than 70%, and the specific surface area is ≥200m 2 / kg.

3. The high thixotropic and high bonding cement-based anchoring material for full anchoring of muddy soft rock according to claim 1, characterized in that: The average particle size of the plastic expansion agent is 2.5-3.9 μm, and the foaming time is ≤12 hours.

4. The high thixotropic and high bonding cement-based anchoring material for full anchoring of muddy soft rock according to claim 1, characterized in that: The viscosity of the hydroxypropyl methylcellulose is 400 Pa·s, and the purity is industrial grade.

5. The high thixotropic and high bonding cement-based anchoring material for full anchoring of muddy soft rock according to claim 1, characterized in that: The polyacrylamide is PAM anion 1200 type.

6. The high thixotropic and high bonding cement-based anchoring material for full anchoring of muddy soft rock according to claim 1, characterized in that: The fumed silica is composed of 20 nm and 1 μm fumed silica in a mass ratio of 2:1, and the purity of both is 99.9%.

7. The high thixotropic and high bonding cement-based anchoring material for full anchoring of muddy soft rock according to claim 1, characterized in that: The dispersible latex powder is vinyl acetate / ethylene copolymer powder, with a solid content of ≥99% and a particle size of 1-7 μm.

8. The high thixotropic and high bonding cement-based anchoring material for full anchoring of muddy soft rock according to claim 1, characterized in that: The silane coupling agent is γ-aminopropyltriethoxysilane.

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