Deep well mudstone grouting anti-seepage reinforcement material with high flow and high water retention and its preparation method

Abstract

The invention discloses a deep well mudstone grouting anti-seepage reinforcement material with high fluidity and high water retention and a preparation method, which belongs to the technical field of grouting materials and is particularly suitable for grouting anti-seepage reinforcement of deep tunnel fissure rock mass. The material is composed of 55-65 parts by weight of silicate cement, 10-25 parts by weight of sulphoaluminate cement, 7-20 parts by weight of mineral powder, 1-5 parts by weight of fly ash, 1-5 parts by weight of gypsum, 28-30 parts by weight of water, 0.82-1.2 parts by weight of water reducer, 0.03-0.044 parts by weight of hydroxypropyl methylcellulose, 0.005-0.012 parts by weight of sodium polyacrylate, 0.01-0.012 parts by weight of sodium alginate, 0.52-0.72 parts by weight of nano silica sol, 0.38-0.56 parts by weight of lithium carbonate, 0.06-0.088 parts by weight of plastic expansion agent, and 0.18-0.26 parts by weight of defoamer. It has controllable gel time, high fluidity, high water retention, micro expansion, high early strength, high strength and low cost.

Description

Technical Field

[0001] The invention belongs to the technical field of grouting materials, and in particular relates to a deep well mudstone grouting anti-seepage reinforcement material with high fluidity and high water retention and a preparation method thereof. Technical Background

[0002] As the depth of coal mining gradually extends, the "five highs and two disturbances" problems caused by deep mining have become increasingly prominent. Deep muddy soft rock tunnels have high ground stress, large water seepage pressure, strong mining impact, and the degree of surrounding rock crushing and the range of the damage circle are significantly aggravated compared to the shallow part, resulting in large deformation of the surrounding rock in deep muddy soft rock tunnels, long duration, and abnormally significant creep damage of the surrounding rock for a long time, which has become a key bottleneck restricting the safe and efficient mining of deep coal resources. Through the delayed grouting of the surrounding rock, the slurry solidifies in the structural surface of the rock mass and fills and reinforces the structural surface, improves the bonding force and internal friction angle of the weak surface of the rock mass, changes the rock microstructure, reduces the rock porosity, enhances the density, impermeability and mechanical strength of the rock mass, and fundamentally enhances the bearing capacity of the engineering rock mass to resist external force damage.

[0003] Common grouting anti-seepage reinforcement materials include the following: single-liquid cement slurry, cement-water glass slurry, and chemical slurry. Cement slurry has become one of the most commonly used materials for deep mud soft rock grouting reinforcement due to its low price and wide source. However, it generally has problems such as long setting time, high water seepage rate, stone rate, slow strength growth and volume shrinkage. Mudstone has developed microcracks, high surface free energy, and high absorption capacity for water in the slurry. Water-absorbing soft rock will further reduce the strength of the rock mass. At present, in order to increase the fluidity of cement slurry in mudstone, the water-cement ratio of the slurry is set to be relatively large. For example, the water-cement ratio of the grouting material for grouting drilling is set to 0.8:1~1.2:1 in the Chinese patent CN113803087B "A method for grouting and reinforcing broken surrounding rock along the goaf of a small coal pillar". An excessively large water-cement ratio causes excess water in the slurry that does not participate in the hydration reaction to penetrate into the mudstone mass, which will significantly weaken the strength of the mudstone, significantly reduce the stone rate of the slurry, and significantly reduce the bonding strength of the slurry-rock interface, thereby causing the grouting of the mudstone mass to fail. In order to prevent the weakening of the slurry-rock interface strength caused by water absorption at the mudstone interface, the water retention of the slurry and mudstone can be improved by adding a large amount of water-retaining agent. For example, in the Chinese patent CN 110845213 B "A kind of soft stratum tunnel advance deep hole grouting reinforcement material and its preparation method", 12% hydroxymethyl cellulose by weight of cement is added to increase the viscosity of the slurry system and thus enhance the water retention. When the viscosity of the slurry is greatly increased, the injection resistance of the slurry increases, the fluidity and permeability of the slurry are significantly reduced, and the diffusion of the slurry grouting is significantly reduced. The contradiction between the fluidity and water retention of the grouting material has become an important factor restricting the grouting reinforcement effect of the mudstone mass. Therefore, developing a grouting material that can achieve high fluidity, strong permeability, high water retention, and a high degree of bonding with the mudstone interface has important application value for grouting reinforcement of deep well muddy soft rock. Summary of the invention

[0004] In view of the shortcomings of the existing technology, a deep well mudstone grouting anti-seepage reinforcement material and a preparation method with high fluidity and high water retention are provided, which has the significant advantages of controllable gel time, high fluidity, high water retention, micro-expansion, high early strength, high strength and low cost, and is particularly suitable for grouting anti-seepage reinforcement of fractured rock masses in deep tunnels.

[0005] To achieve the above technical purpose, the present invention discloses a deep well mudstone grouting anti-seepage reinforcement material with high fluidity and high water retention, which is composed of: 55-65 parts by weight of silicate cement, 10-25 parts by weight of sulphoaluminate cement, 7-20 parts by weight of mineral powder, 1-5 parts by weight of fly ash, 1-5 parts by weight of gypsum, 28-30 parts by weight of water, 0.82-1.2 parts by weight of water reducer, 0.03-0.044 parts by weight of hydroxypropyl methylcellulose, 0.005-0.012 parts by weight of sodium polyacrylate, 0.01-0.012 parts by weight of sodium alginate, 0.52-0.72 parts by weight of nano silica sol, 0.38-0.56 parts by weight of lithium carbonate, 0.06-0.088 parts by weight of plastic expansion agent and 0.18-0.26 parts by weight of defoamer.

[0006] The silicate cement is PO 42.5 ordinary silicate cement; the sulphoaluminate cement is R·SAC 42.5 grade sulphoaluminate cement; the mineral powder is S95 grade mineral powder; the fly ash is secondary fly ash with a fineness of 1250 mesh; the SiO2 content of the silica ash is 96%; the water reducer is a high-performance polycarboxylate water reducer with a water reduction rate of ≥35%.

[0007] Furthermore, the gypsum is hemihydrate gypsum with a fineness of 1200 meshes.

[0008] Furthermore, the viscosity of the hydroxypropyl methylcellulose is 400 Pa·s, and the purity is industrial grade.

[0009] Furthermore, the molecular weight of the sodium polyacrylate is 300w and the purity is industrial grade.

[0010] Furthermore, the nano-silica sol has a concentration of 20% and an average particle size of 30 nm.

[0011] Furthermore, the average particle size of the plastic expansion agent is 2.5 to 3.9 μm, and the foaming time is ≤12 hours.

[0012] A method for preparing a deep well mudstone grouting anti-seepage reinforcement material with high flow and high water retention, the steps are as follows:

[0013] (1) Put silicate cement, sulphoaluminate cement, mineral powder, fly ash, gypsum, water, water reducer, hydroxypropyl methylcellulose, sodium polyacrylate, sodium alginate, lithium carbonate, nano silica sol and plastic expansion agent into a mixer according to the material ratio, stir at a low speed of 120-140 r / min for 1 min, and stir at a high speed of 250-350 r / min for 1 min to obtain a preliminary slurry.

[0014] (2) Add defoaming agent according to the material ratio, stir at a high speed of 250-350 r / min for 2 min, let the slurry stand and place the ultrasonic transmitter into the slurry, use ultrasonic excitation for 1 min, and then cycle high-speed stirring-ultrasonic excitation-high-speed stirring twice to obtain a high-flow and high-water-retention mudstone grouting anti-seepage reinforcement material.

[0015] Beneficial effects: Compared with existing grouting materials, the deep well mudstone grouting anti-seepage reinforcement material with high flow and high water retention and the preparation method of the present invention have the following beneficial effects:

[0016] 1) The present invention modifies silicate cement by using sulphoaluminate cement, mineral admixtures and modified admixtures. The materials used are all powder materials, the configuration is simple and convenient, and silicate cement is used as the main body, so the overall cost is low.

[0017] 2) The present invention improves the dispersibility of additives and admixtures of different particle sizes and reduces the friction resistance between particles of different particle sizes through the compounding of high-performance polycarboxylate water-reducing agent, nano-silica sol and plastic expansion agent, and through the innovation of stirring process and ultrasonic excitation, so as to make the slurry material have excellent fluidity, the initial fluidity exceeds 480mm, the injection resistance is extremely low, and the high fluidity and strong permeability regulation of the slurry with a water-cement ratio of 0.28 is achieved.

[0018] 3) The present invention forms a triple cross-linked network of water-soluble polymers in the system by compounding hydroxypropyl methylcellulose with a low dosage of 400Pa·s, sodium polyacrylate with a molecular weight of 300w and sodium alginate, which greatly improves the cohesiveness and water retention of the slurry without affecting the fluidity of the slurry, realizes the self-water retention and self-maintenance of the slurry in a non-humid environment, significantly reduces the absorption of water in the slurry by mudstone, and improves the density and adhesion of the interface between the slurry and the mudstone. At the same time, it can achieve low loss (≤5%) of material properties under environmental maintenance at a temperature of 5-10°C and a relative humidity of 40-60%, and can adapt to a variety of grouting and anti-seepage reinforcement projects of deep well mudstone surrounding rocks in low-temperature-non-humid environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a nanometer-scale particle size distribution diagram of a deep well mudstone grouting anti-seepage reinforcement material with high flowability and high water retention in an embodiment of the present invention;

[0020] Figure 2 This is a slurry fluidity test diagram of a deep well mudstone grouting anti-seepage reinforcement material with high fluidity and high water retention in an embodiment of the present invention;

[0021] Figure 3 This is a microstructure diagram of the consolidated body of the deep well mudstone grouting anti-seepage reinforcement material with high flow and high water retention in an embodiment of the present invention;

[0022] Figure 4This is a microstructure comparison diagram of the bonding performance between the deep well mudstone grouting anti-seepage reinforcement material with high flow and high water retention and the mudstone interface in the embodiment of the present invention; (a) the conventional reinforcement material and the mudstone bonding interface have gaps, (b) the material and the mudstone bonding interface are dense and have no gaps DETAILED DESCRIPTION

[0023] An embodiment of the present invention is further described below in conjunction with the accompanying drawings:

[0024] Example 1

[0025] A deep well mudstone grouting anti-seepage reinforcement material with high fluidity and high water retention is made of the following raw materials in the following weight proportions: 650 parts of silicate cement, 250 parts of sulphoaluminate cement, 200 parts of mineral powder, 10 parts of fly ash, 30 parts of gypsum, 300 parts of water, 10 parts of water reducing agent, 0.37 parts of hydroxypropyl methylcellulose, 0.05 parts of sodium polyacrylate, 0.1 parts of sodium alginate, 5.2 parts of nano silica sol, 5.6 parts of lithium carbonate, 0.6 parts of plastic expansion agent and 1.8 parts of defoaming agent.

[0026] The silicate cement is PO 42.5 ordinary silicate cement. The sulphoaluminate cement is R·SAC 42.5 grade sulphoaluminate cement. The mineral powder is S95 grade mineral powder. The fly ash is secondary fly ash with a fineness of 1250 mesh. The SiO2 content of silica ash is 96%. The water reducer is a high-performance polycarboxylic acid water reducer with a water reduction rate of ≥35%. The gypsum is semi-hydrated gypsum with a fineness of 1200 mesh. The viscosity of hydroxypropyl methylcellulose is 400Pa·s and the purity is industrial grade. The molecular weight of sodium polyacrylate is 300w and the purity is industrial grade. The concentration of nano silica sol is 20% and the average particle size is 30nm. The average particle size of the plastic expansion agent is 2.5-3.9μm, and the foaming time is ≤12h.

[0027] A method for preparing a deep well mudstone grouting anti-seepage reinforcement material with high flowability and high water retention, comprising the following steps:

[0028] (1) Put silicate cement, sulphoaluminate cement, mineral powder, fly ash, gypsum, water, water reducer, hydroxypropyl methylcellulose, sodium polyacrylate, sodium alginate, lithium carbonate, nano silica sol and plastic expansion agent into a mixer according to the material ratio, stir at a low speed of 120 r / min for 1 min, and stir at a high speed of 250 r / min for 1 min to obtain a preliminary slurry.

[0029] (2) Add defoaming agent according to the material ratio, stir at a high speed of 250 r / min for 2 min, let the slurry stand and place the ultrasonic transmitter into the slurry, use ultrasonic excitation for 1 min, and then cycle high-speed stirring-ultrasonic excitation-high-speed stirring twice to obtain a high-flow and high-water-retention mudstone grouting anti-seepage reinforcement material.

[0030] Example 2

[0031] A deep well mudstone grouting anti-seepage reinforcement material with high fluidity and high water retention is made of the following raw materials in parts by weight: 650 parts of silicate cement, 100 parts of sulphoaluminate cement, 150 parts of mineral powder, 50 parts of fly ash, 50 parts of gypsum, 280 parts of water, 12 parts of water reducing agent, 0.3 parts of hydroxypropyl methylcellulose, 0.05 parts of sodium polyacrylate, 0.1 parts of sodium alginate, 6 parts of nano silica sol, 3.8 parts of lithium carbonate, 0.88 parts of plastic expansion agent and 2.6 parts of defoaming agent.

[0032] The silicate cement is PO 42.5 ordinary silicate cement. The sulphoaluminate cement is R·SAC 42.5 grade sulphoaluminate cement. The mineral powder is S95 grade mineral powder. The fly ash is secondary fly ash with a fineness of 1250 mesh. The SiO2 content of silica ash is 96%. The water reducer is a high-performance polycarboxylic acid water reducer with a water reduction rate of ≥35%. The gypsum is semi-hydrated gypsum with a fineness of 1200 mesh. The viscosity of hydroxypropyl methylcellulose is 400Pa·s and the purity is industrial grade. The molecular weight of sodium polyacrylate is 300w and the purity is industrial grade. The concentration of nano silica sol is 20% and the average particle size is 30nm. The average particle size of the plastic expansion agent is 2.5-3.9μm, and the foaming time is ≤12h.

[0033] A method for preparing a deep well mudstone grouting anti-seepage reinforcement material with high flowability and high water retention, comprising the following steps:

[0034] (1) Put silicate cement, sulphoaluminate cement, mineral powder, fly ash, gypsum, water, water reducer, hydroxypropyl methylcellulose, sodium polyacrylate, sodium alginate, lithium carbonate, nano silica sol and plastic expansion agent into a mixer according to the material ratio, stir at a low speed of 140 r / min for 1 min, and stir at a high speed of 350 r / min for 1 min to obtain a preliminary slurry.

[0035] (2) Add defoaming agent according to the material ratio, stir at a high speed of 350 r / min for 2 min, let the slurry stand and place the ultrasonic transmitter into the slurry, use ultrasonic excitation for 1 min, and then cycle high-speed stirring-ultrasonic excitation-high-speed stirring twice to obtain a high-flow and high-water-retention mudstone grouting anti-seepage reinforcement material.

[0036] Example 3

[0037] A deep well mudstone grouting anti-seepage reinforcement material with high fluidity and high water retention is made of the following raw materials in parts by weight: 550 parts of silicate cement, 250 parts of sulphoaluminate cement, 200 parts of mineral powder, 50 parts of fly ash, 50 parts of gypsum, 300 parts of water, 12 parts of water reducer, 0.44 parts of hydroxypropyl methylcellulose, 0.1 parts of sodium polyacrylate, 0.1 parts of sodium alginate, 7 parts of nano-silica sol, 5.6 parts of lithium carbonate, 0.88 parts of plastic expansion agent and 2.6 parts of defoaming agent.

[0038] The silicate cement is PO 42.5 ordinary silicate cement. The sulphoaluminate cement is R·SAC 42.5 grade sulphoaluminate cement. The mineral powder is S95 grade mineral powder. The fly ash is secondary fly ash with a fineness of 1250 mesh. The SiO2 content of silica ash is 96%. The water reducer is a high-performance polycarboxylic acid water reducer with a water reduction rate of ≥35%. The gypsum is semi-hydrated gypsum with a fineness of 1200 mesh. The viscosity of hydroxypropyl methylcellulose is 400Pa·s and the purity is industrial grade. The molecular weight of sodium polyacrylate is 300w and the purity is industrial grade. The concentration of nano silica sol is 20% and the average particle size is 30nm. The average particle size of the plastic expansion agent is 2.5-3.9μm, and the foaming time is ≤12h.

[0039] A method for preparing a deep well mudstone grouting anti-seepage reinforcement material with high flowability and high water retention, comprising the following steps:

[0040] (1) Put silicate cement, sulphoaluminate cement, mineral powder, fly ash, gypsum, water, water reducer, hydroxypropyl methylcellulose, sodium polyacrylate, sodium alginate, lithium carbonate, nano-silica sol and plastic expansion agent into a mixer according to the material ratio, stir at a low speed of 130 r / min for 1 min, and stir at a high speed of 300 r / min for 1 min to obtain a preliminary slurry.

[0041] (2) Add defoaming agent according to the material ratio, stir at a high speed of 300 r / min for 2 min, let the slurry stand and place the ultrasonic transmitter into the slurry, use ultrasonic excitation for 1 min, and then cycle high-speed stirring-ultrasonic excitation-high-speed stirring twice to obtain a high-flow and high-water-retention mudstone grouting anti-seepage reinforcement material.

[0042] Example 4

[0043] A deep well mudstone grouting anti-seepage reinforcement material with high fluidity and high water retention is made of the following raw materials in parts by weight: 600 parts of silicate cement, 150 parts of sulphoaluminate cement, 150 parts of mineral powder, 40 parts of fly ash, 40 parts of gypsum, 280 parts of water, 12 parts of a water reducing agent, 0.44 parts of hydroxypropyl methylcellulose, 0.05 parts of sodium polyacrylate, 0.1 parts of sodium alginate, 5.2 parts of nano silica sol, 4.2 parts of lithium carbonate, 0.75 parts of a plastic expansion agent, and 2.2 parts of a defoaming agent.

[0044] The silicate cement is PO 42.5 ordinary silicate cement. The sulphoaluminate cement is R·SAC 42.5 grade sulphoaluminate cement. The mineral powder is S95 grade mineral powder. The fly ash is secondary fly ash with a fineness of 1250 mesh. The SiO2 content of silica ash is 96%. The water reducer is a high-performance polycarboxylic acid water reducer with a water reduction rate of ≥35%. The gypsum is semi-hydrated gypsum with a fineness of 1200 mesh. The viscosity of hydroxypropyl methylcellulose is 400Pa·s and the purity is industrial grade. The molecular weight of sodium polyacrylate is 300w and the purity is industrial grade. The concentration of nano silica sol is 20% and the average particle size is 30nm. The average particle size of the plastic expansion agent is 2.5-3.9μm, and the foaming time is ≤12h.

[0045] A method for preparing a deep well mudstone grouting anti-seepage reinforcement material with high flowability and high water retention, comprising the following steps:

[0046] (1) Put silicate cement, sulphoaluminate cement, mineral powder, fly ash, gypsum, water, water reducer, hydroxypropyl methylcellulose, sodium polyacrylate, sodium alginate, lithium carbonate, nano silica sol and plastic expansion agent into a mixer according to the material ratio, stir at a low speed of 140 r / min for 1 min, and stir at a high speed of 350 r / min for 1 min to obtain a preliminary slurry.

[0047] (2) Add defoaming agent according to the material ratio, stir at a high speed of 350 r / min for 2 min, let the slurry stand and place the ultrasonic transmitter into the slurry, use ultrasonic excitation for 1 min, and then cycle high-speed stirring-ultrasonic excitation-high-speed stirring twice to obtain a high-flow and high-water-retention mudstone grouting anti-seepage reinforcement material.

[0048] The relevant performances of the above embodiments were tested through slurry truncated cone fluidity test, slurry static water separation rate test, solidification rate test, mudstone water separation rate test, vertical expansion rate test, 3-day compressive strength and 28-day compressive strength.

[0049] After testing, the test results of Examples 1 to 4 are shown in Table 1. As can be seen from the table, the dispersibility of the additives and additives with different particle sizes is improved by compounding the high-performance polycarboxylate water-reducing agent, nano-silica sol and plastic expansion agent, and by the innovation of stirring process and ultrasonic excitation, as shown in Table 1. Figure 1 As shown in the figure, the friction resistance between particles of different sizes is reduced, making the slurry fluidity excellent. The initial fluidity of the slurry in the ratio range exceeds 480mm. Figure 2As shown. By compounding hydroxypropyl methylcellulose with a low dosage of 400Pa·s, sodium polyacrylate with a molecular weight of 300w and sodium alginate, a water-soluble polymer with a triple cross-linked network is formed in the system. Ultrasonic vibration makes the polymer cross-linked network evenly distributed, which greatly improves the cohesiveness and water retention of the slurry without affecting the fluidity of the slurry, significantly reduces the absorption of water in the slurry by mudstone, and improves the microstructural density of the stone body, as shown in the figure. Figure 3 As shown in Figure 2, the density of the bonding interface between the slurry and the mudstone is improved and the void volume in the interface area is reduced. Figure 4 As shown in (a) the voids at the bonding interface between the conventional reinforcement material and the mudstone and (b) the dense void-free bonding interface between the present material and the mudstone, the stability of the slurry is greatly improved.

[0050] Table 1 Test results of Examples 1 to 4

[0051]

[0052] Comparative Example 1

[0053] The same as Example 1, the only difference is that one of hydroxypropyl methylcellulose, sodium polyacrylate, sodium alginate, silica sol, and plastic expansion agent is removed from the material ratio, and other parameters are the same as those in Example 1 and will not be repeated. The test results are shown in Table 2 below.

[0054] It can be seen from Table 2 combined with the data of Example 1 that when a certain component in the grouting anti-seepage reinforcement material is removed, it will have a significant impact on the overall performance of the slurry, seriously affecting the fluidity and water retention of the slurry. Among them, when hydroxypropyl methylcellulose, sodium polyacrylate and sodium alginate are removed, the fluidity of the slurry increases, the water retention decreases, the water separation rate and the water absorption rate of mudstone increase. For example, when hydroxypropyl methylcellulose is removed, the water separation rate increases from 0 to 1.22%, the water absorption rate increases by 11.5 times, the solidification rate decreases, and the compressive strength increases. The degree of influence is: hydroxypropyl methylcellulose>sodium polyacrylate>sodium alginate; after the nano-silica sol is removed, the fluidity and water retention of the slurry are less affected, but the compressive strength is more affected. The compressive strength of 3 days is reduced by 9.7%, and the compressive strength of 28 days is reduced by 10.6%; after the plastic expansion agent is removed, the fluidity of the slurry is significantly reduced, the water retention is less affected, the slurry does not expand, and the compressive strength increases. From the above analysis, it can be seen that when any of the above components in the grouting anti-seepage reinforcement material is removed, it will have an adverse effect on a certain performance of the grouting material, and the above materials are indispensable.

[0055] Table 2 Effect of removing a certain component on performance

[0056]

[0057] Comparative Example 2

[0058] Comparison of configuration methods: no ultrasound, one-time addition

[0059] The method is the same as Example 1, except that the ultrasonic transmitter is not used to ultrasonically excite the slurry in the slurry preparation method, and other materials and steps are the same as Example 1, which will not be described in detail. The test results are shown in Table 3 below.

[0060] Table 3 Comparison of slurry performance without ultrasonic excitation

[0061]

[0062]

[0063] It can be seen from the above table that when the ultrasonic excitation step is removed, the fluidity, expansion rate and strength of the slurry are significantly affected. On the one hand, ultrasound can make the distribution of the three polymer networks more uniform, and can also make the water reducer disperse more evenly, thereby reducing the friction between particles. After the ultrasonic excitation is removed, the friction between particles increases and the fluidity becomes worse. At the same time, ultrasonic excitation can assist in the elimination of harmful bubbles in the slurry, thereby enhancing the defoaming ability of the defoaming agent. After the ultrasonic excitation is removed, the amount of harmful bubbles in the system increases, the expansion rate of the slurry increases, the density decreases, and therefore the compressive strength decreases.

[0064] Comparative Example 3

[0065] The same as Example 1, the only difference is that in the slurry preparation method, the defoamer and other materials are added to the material in batches for stirring, and the other materials and steps are the same as Example 1, which will not be repeated. The test results are shown in Table 4 below.

[0066] Table 4 Effect of defoamer addition order on slurry properties

[0067]

[0068] As can be seen from the above table, the order of adding defoamers has a great influence on the performance of the slurry. When added with other materials at the beginning, the fluidity and expansion will be reduced. Because the water reducer, hydroxypropyl methylcellulose, sodium polyacrylate and sodium alginate in the system all have a certain air entraining effect, stirring at this time will introduce more bubbles into the slurry. If the defoamer is added at the beginning, after the subsequent ultrasonic oscillation excitation, both the beneficial small bubbles and the harmful large bubbles will be fully eliminated, and the small bubbles in the system will be reduced, which will reduce the fluidity of the slurry and the expansion rate. Therefore, the defoamer needs to be added after the initial stirring, so that the beneficial small bubbles can be introduced first, and the harmful large bubbles can be eliminated by the ultrasonic excitation to assist the defoamer, so that the fluidity and expansion rate of the slurry can be effectively improved.

Claims

1. A deep well mudstone grouting anti-seepage reinforcement material with high flow and high water retention, characterized in that: The composition is: 55-65 parts by weight of silicate cement, 10-25 parts by weight of sulphoaluminate cement, 7-20 parts by weight of mineral powder, 1-5 parts by weight of fly ash, 1-5 parts by weight of gypsum, 28-30 parts by weight of water, 0.82-1.2 parts by weight of water reducer, 0.03-0.044 parts by weight of hydroxypropyl methylcellulose, 0.005-0.012 parts by weight of sodium polyacrylate, 0.01-0.012 parts by weight of sodium alginate, 0.52-0.72 parts by weight of nano silica sol, 0.38-0.56 parts by weight of lithium carbonate, 0.06-0.088 parts by weight of plastic expansion agent, and 0.18-0.26 parts by weight of defoamer; The silicate cement is PO 42.5 ordinary silicate cement; the sulphoaluminate cement is R·SAC 42.5 grade sulphoaluminate cement; the mineral powder is S95 grade mineral powder; the fly ash is secondary fly ash with a fineness of 1250 mesh; the water reducer is a high-performance polycarboxylate water reducer with a water reduction rate of ≥35%; The gypsum is semi-hydrated gypsum with a fineness of 1200 mesh; the molecular weight of sodium polyacrylate is 300w and the purity is industrial grade; the viscosity of hydroxypropyl methylcellulose is 400 Pa·s and the purity is industrial grade; The deployment steps are as follows: (1) Put silicate cement, sulphoaluminate cement, mineral powder, fly ash, gypsum, water, water reducer, hydroxypropyl methylcellulose, sodium polyacrylate, sodium alginate, lithium carbonate, nano-silica sol and plastic expansion agent into a mixer according to the material ratio, stir at a low speed of 120-140 r / min for 1 min, and stir at a high speed of 250-350 r / min for 1 min to obtain a preliminary slurry. (2) Add defoaming agent according to the material ratio, stir at a high speed of 250-350 r / min for 2 min, let the slurry stand, place the ultrasonic transmitter into the slurry, use ultrasonic excitation for 1 min, and then cycle high-speed stirring-ultrasonic excitation-high-speed stirring twice to obtain a high-flow and high-water-retention mudstone grouting anti-seepage reinforcement material.

2. The deep well mudstone grouting anti-seepage reinforcement material with high fluidity and high water retention according to claim 1 is characterized in that: The nano silica sol has a concentration of 20% and an average particle size of 30 nm.

3. The deep well mudstone grouting anti-seepage reinforcement material with high fluidity and high water retention according to claim 1 is 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.

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