Industrial solid waste-based high-flow-state solidified sludge slurry and preparation method thereof

Abstract

The shield soil synchronous grouting material provided by the invention takes the shield muck as a main material, the high-performance nano mineral-based cementing material and the auxiliary materials are added and mixed to form the slurry for shield synchronous grouting, and the slurry has the advantages of simplicity in mixing, easiness in pumping, floating resistance, leakage resistance and the like. The main raw materials comprise slag powder, fly ash and muck, so that sustainable development of engineering construction is realized. In addition, a large dosage of muck is doped, so that the use of natural gravel is reduced, the preparation cost of the slurry is further reduced, and the influence of price increase of the gravel on engineering construction is alleviated.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of solid waste resource recycling, and particularly relates to an industrial solid waste-based high-flow-state solidified sludge slurry and a preparation method thereof. BACKGROUND

[0002] A large amount of cutting spoil is generated during shield construction. In China, less than 5% of the huge amount of shield spoil is resourcefully utilized. The spoil is usually piled in nearby spoil dumps, and a disposal fee is generally charged in various places, about 20-90 yuan / m 3 . Therefore, the piling of shield spoil not only causes serious environmental pollution and resource waste, but also increases construction cost. In the era of developing green and low-carbon transportation, resourceful utilization of shield spoil has become an urgent engineering problem to be solved.

[0003] The synchronous slurry as a backfilling material for the lining segment of a shield tunnel plays a crucial role in preventing the segment from floating, misaligning, being damaged and leaking water, and directly affects the durability and safety of the structure. How to achieve the anti-floating and anti-leakage goals of the shield tunnel depends on the use of a synchronous grouting material with specific properties, which should have good fluidity, stability, short initial setting time (in a closed environment), high early strength, low bleeding rate and high stone rate. The existing subway shield mortar is generally a cement-based mortar, and the components are cement, fly ash, river sand, bentonite, additive and water, which has problems of high cost and large consumption of natural resources. SUMMARY

[0004] In view of the above problems, an industrial solid waste-based high-flow-state solidified sludge slurry and a preparation method thereof are provided to overcome the above problems or at least partially solve the above problems, in particular:

[0005] The preparation method of the industrial solid waste-based high-flow-state solidified sludge slurry comprises the following steps:

[0006] Mixing the spoil with water to prepare a slurry with a specific gravity of 1.45-1.6 g / cm 3 ;

[0007] Adding an industrial solid waste-based solidifying agent to the slurry according to 10%-30% of the weight of the slurry, and pumping the prepared slurry into a slurry storage tank after stirring for 5 minutes;

[0008] The spoil is cutting spoil generated during shield construction, and the mass fraction of the raw materials of the industrial solid waste-based solidifying agent is: 100-200 parts of desulfurized gypsum powder, 600-700 parts of slag powder, 100-200 parts of ordinary Portland cement, 50-100 parts of first-grade fly ash, and 1-4 parts of polycarboxylic acid water reducer.

[0009] Optionally, the industrial solid waste-based curing agent raw materials are mixed by a dry powder mixer.

[0010] Optionally, the slag powder is a high-activity slag powder with a particle size of less than or equal to 100 nanometers.

[0011] Optionally, the content of hemihydrate gypsum in the desulfurization gypsum powder is greater than or equal to 85%, and the content of chloride ions is less than or equal to 0.01%.

[0012] Optionally, the activity index of the slag powder is: 7d is greater than or equal to 75%, and 28d is greater than or equal to 95%.

[0013] Optionally, the industrial solid waste-based curing agent further comprises 0.3-1 parts of a sulphoaluminate cement and 0.05 parts of an organic silicon water-repellent agent.

[0014] Optionally, 0.1-0.5 parts of a viscosity regulator are further added to the slurry, wherein the viscosity regulator is hydroxypropyl methyl cellulose.

[0015] The application further provides an industrial solid waste-based high-fluidity solidified sludge slurry prepared by the method.

[0016] The shield soil synchronous grouting material provided by the application is a slurry formed by mixing a shield muck as a main material, a high-performance nano mineral-based cementing material and auxiliary materials, and has the advantages of simple mixing, easy pumping, anti-floating and anti-leakage. The main raw materials of the slurry include slag powder, fly ash and muck, so that the application of the application realizes the sustainable development of engineering construction. In addition, the large-dose addition of muck reduces the use of natural sand and gravel, thereby reducing the preparation cost of the slurry and mitigating the influence of the price increase of sand and gravel on engineering construction. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the application, the following will briefly introduce the drawings needed to be used in the description of the application. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0018] Figure 1 is a preparation method flow chart of an industrial solid waste-based high-fluidity solidified sludge slurry provided by an embodiment of the application;

[0019] Figure 2 is a ground settlement detection measurement point arrangement situation schematic diagram of materials in the comparative example 1 of the application;

[0020] Figure 3 is a ground settlement detection measurement point arrangement situation schematic diagram of the embodiment 2 of the application;

[0021] Figure 4Fig. 1 is a monitoring data chart of surface subsidence of the grouting interval position of the material of Comparative Example 1 and the material of Example 2 of the present application. DETAILED DESCRIPTION

[0022] In order to make the above objectives, characteristics and advantages of the present application more apparent, comprehensible and easier to understand, the present application will be further described in detail below in combination with the drawings and specific embodiments. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making any creative efforts belong to the scope of protection of the present application.

[0023] Reference Figure 1 Fig. 1 is a monitoring data chart of surface subsidence of the grouting interval position of the material of Comparative Example 1 and the material of Example 2 of the present application.

[0024] A preparation method of an industrial solid waste-based high-fluidity solidified silt slurry, comprising the following steps:

[0025] Mixing the slag soil with water to prepare a slurry with a specific gravity of 1.45-1.6 g / cm 3

[0026] According to 10%-30% of the weight of the slurry, adding an industrial solid waste-based solidifying agent to the slurry, and after stirring for 5 minutes, pumping the prepared slurry into a slurry storage tank;

[0027] In the present application, the slag soil is the cutting spoil produced in shield construction, and the water can be tap water. The mass fraction of the raw materials of the industrial solid waste-based solidifying agent is: 100-200 parts of desulfurization gypsum powder, 600-700 parts of slag powder, 100-200 parts of ordinary Portland cement, 50-100 parts of first-grade fly ash, and 1-4 parts of polycarboxylic acid water reducer.

[0028] In the embodiments of the present application, the raw materials of the industrial solid waste-based solidifying agent can be first mixed by a dry powder mixer.

[0029] In actual application, the cutting spoil produced in shield tunnel construction can be first mixed with conventional tap water in a proportioning manner, and stirred uniformly by a mechanical stirring device, so as to control the specific gravity of the slurry to 1.45-1.6 g / cm 3 ​It can be understood that when the specific gravity is less than 1.45, the solid phase content of the slurry is insufficient, which can cause the strength of the solidified body to deteriorate, and when the specific gravity is higher than 1.6, the viscosity increases sharply, which can cause the risk of pumping blockage, and the slurry specific gravity range corresponds to a water content of 40%-45%, which can simultaneously optimize the rheological properties and the efficiency of the gelation reaction. Then, 10%-30% of the total mass of the industrial solid waste-based solidifying agent (the specific amount is dynamically adjusted according to the formation characteristics: 25%-30% is used in high-permeability sand layers to enhance the stone rate, and 10%-15% is used in low-permeability clay layers to avoid slurry retention) is added to the slurry, and the solidifying agent is prepared by pre-mixing five components in a dry powder mixer: 100-200 parts of desulfurized gypsum powder; 600-700 parts of slag powder; 100-200 parts of ordinary Portland cement; 50-100 parts of first-grade fly ash; and 1-4 parts of polycarboxylic acid water reducing agent. After feeding, the preset rotating speed can be continuously stirred for 5 minutes, so that the shear rate of the slurry breaks through the critical value of Bingham fluid, shear thinning is realized, the thixotropy recovery time of the slurry is relatively short, and the slump degree also meets the pumping requirements of shield synchronous grouting. Finally, the final product is pumped into a slurry storage tank for low-speed stirring to prevent segregation.

[0030] Further, the slag powder can be high-activity slag powder with a particle size of ≤100 nanometers.

[0031] In the embodiments of the present application, the slag powder can be high-activity slag powder treated by deep nanocrystallization. Under the synergistic action of the sulfate activation of desulfurized gypsum and the alkaline environment of cement, the depolymerization efficiency of the glass body structure of the slag can be greatly improved, the active components can be quickly released, and a dense nanogel network can be formed. Therefore, the performance of the slurry can be significantly optimized: the early strength development is accelerated, the late strength is significantly enhanced, the setting time is effectively shortened, and the ion permeation resistance is comprehensively improved. In view of the characteristics of easy agglomeration of nanoparticles, a special dispersant can also be introduced to maintain the stability of the system. In specific applications, the amount of the solidifying agent can be adaptively adjusted according to the geological conditions, and excellent diffusion and sealing effects can be achieved in complex formations.

[0032] In the embodiments of the present application, the content of hemihydrate gypsum in the desulfurized gypsum powder can be ≥85%, and the content of chloride ions can be ≤0.01%.

[0033] It can be understood that the above indexes can guarantee the reactivity of gypsum by flash calcination process, and the deep removal of chloride ions can be realized by fresh water centrifugal separation; high-purity hemihydrate gypsum can improve the dissociation efficiency of the slag glass body by sulfate, accelerate the nucleation rate of early gel, and avoid the strength attenuation caused by the wrapping of dihydrate phase; and reducing the content of chloride ions can also eliminate the risk of steel corrosion and simultaneously inhibit the salt expansion crystallization in the later stage, thereby ensuring the durability of the solidified body.

[0034] In the embodiments of the present application, the activity index of the slag powder can be: 7d≥75%, and 28d≥95%.

[0035] It can be understood that the early activity index of the slag powder can be higher than the conventional level, and the long-term activity index is close to the benchmark cement performance. The index is realized by selecting slag raw materials with high glass content and optimizing the powder fineness, and by means of the synergistic effect of sulfate activator and alkaline environment in the solidification system, the high-efficiency dissociation of slag glass network is promoted and a dense gel structure is formed. The early activity ensures that the slurry quickly establishes a strength support system, effectively controls the segment displacement risk in the tunnel construction stage; the long-term activity ensures that the solidification body forms a stable microstructure, so that the lining structure has good impermeability and durability.

[0036] Further, the industrial solid waste-based solidification agent can further include 0.3-1 parts of sulphoaluminate cement and 0.05 parts of organic silicon hydrophobic agent.

[0037] It can be understood that sulphoaluminate cement water can generate ettringite crystal network, which can build a high-strength skeleton in a short time, significantly improve the early strength of the slurry and produce a precise matching shrinkage micro-expansion effect, eliminating the segment backing cavity; the synchronous addition of the organic silicon hydrophobic agent self-assembles a molecular film on the capillary pore wall of the solidification body, increases the pore contact angle to the hydrophobic level, greatly blocks the penetration of water and erosive ions, greatly reduces the water absorption of the slurry and improves the salt corrosion resistance. The micro-alkaline environment created by sulphoaluminate cement can improve the film-forming efficiency of organic silicon, and the hydrophobic film can protect the ettringite network from groundwater erosion, which can effectively improve the durability of the segment joint in harsh environments such as cross-sea tunnels,

[0038] Further, 0.1-0.5 parts of a viscosity regulator can be added to the slurry, wherein the viscosity regulator is hydroxypropyl methyl cellulose.

[0039] In the embodiments of the present application, 0.1-0.5 parts of hydroxypropyl methyl cellulose (HPMC) can also be added to the slurry as a viscosity regulator, which forms a dynamic three-dimensional network structure in an alkaline environment: through hydrogen bonding, the apparent viscosity of the slurry is increased to a stable interval when at rest, effectively suspending the solid phase particles and eliminating the risk of segregation; when subjected to pumping shear, the network is temporarily detached, realizing a cliff-like drop in viscosity, ensuring the smoothness of high-flow grouting. The component synchronously builds a water-permeable barrier, cooperates with the organic silicon hydrophobic agent to block the migration of water in capillary pores, and suppresses the bleeding rate to a low level, and delays the dehydration and pulverization of ettringite crystals. The flexible cellulose chain wraps the rigid ettringite network, inhibiting the hydration fluctuation of sulphoaluminate cement; the surface potential of nano slag is increased to enhance the dispersion stability; the dosage of external additives is reduced through competitive adsorption with polycarboxylic acid superplasticizer.

[0040] The main raw materials of the present application are slag powder, fly ash and slag, so the application of the present application realizes the sustainable development of engineering construction. In addition, the large-dose addition of slag reduces the use of natural sand and gravel, thereby reducing the preparation cost of the slurry and alleviating the influence of the price increase of sand and gravel on engineering construction.

[0041] The shield earth synchronous grouting material is formed by mixing the shield earth as the main material, high-performance nano mineral-based cementitious material and auxiliary materials, and has the advantages of simple mixing, easy pumping, anti-floating, anti-leakage and the like.

[0042] The main role of the high-performance nano mineral-based cementitious material is to stimulate the activity of soil particles, so that the soil particles and the nano mineral-based cementitious material form a new cementitious material for self-bonding and solidification. Under the condition of water, the nano mineral-based cementitious material can be bonded into a whole cementitious material by physical and chemical reactions of itself, and the product can bond the scattered material with a particle size of less than 10 pm into a whole cementitious material. The slurry prepared by the nano mineral-based cementitious material has a shrinkage rate of less than 0.06%, absorbs water and heat during the reaction process, and the solidified body slightly expands after forming, thereby improving the stability of the formed tunnel and having a good supporting effect on the floating and leakage of the shield tunnel.

[0043] The slurry prepared by the technology can be directly transported to the tunnel for use after sampling and inspection. Compared with the traditional slurry, the slurry prepared by the technology has the advantages of short initial setting time, high early strength, good stability, adjustable proportion, reduced ground settlement, reduced segment floating amount, reduced structural leakage water and improved tunnel forming quality.

[0044] The application also provides an industrial solid waste-based high-fluidity solidified sludge slurry prepared by the above method.

[0045] In addition, in order to facilitate understanding, the application also provides the following examples:

[0046] Comparative Example 1

[0047] The following raw materials are used in Comparative Example 1: 433 parts of natural sand, 93 parts of tap water, 110 parts of first-grade fly ash, 27 parts of slaked lime, 17 parts of sodium-based bentonite and 1 part of polycarboxylic acid water reducer. After mechanical stirring for 5 minutes, each sample is manually poured and tamped, and the compressive strength test piece is subjected to standard curing. The properties of Comparative Example 1 are shown in Table 1.

[0048]

[0049] Table 1

[0050] Example 1

[0051] The following raw materials are used in Example 1: 1920 parts of shield cutting slag, 1280 parts of tap water, and the slag is pre-configured to have a specific gravity of 1.45 g / cm 3Desulfurization gypsum 140 parts, slag 700 parts, ordinary Portland cement 120 parts, and polycarboxylic acid water reducing agent 1 part. After mechanical stirring for 5 minutes, each sample was manually poured and tamped, and the compressive strength test piece was subjected to standard curing. The properties of Example 1 are shown in Table 2.

[0052]

[0053] Table 2

[0054] Example 2

[0055] The following materials were used in Example 2 in the following mass fractions: 1860 parts of shield cutting spoil, 1360 parts of tap water, and the spoil was pre-configured into a slurry with a specific gravity of 1.5 g / cm 3 Desulfurization gypsum 140 parts, slag 700 parts, ordinary Portland cement 120 parts, and polycarboxylic acid water reducing agent 1 part. After mechanical stirring for 5 minutes, each sample was manually poured and tamped, and the compressive strength test piece was subjected to standard curing. The properties of Example 2 are shown in Table 3.

[0056]

[0057] Table 3

[0058] Example 3

[0059] The following materials were used in Example 3 in the following mass fractions: 1760 parts of shield cutting spoil, 1440 parts of tap water, and the spoil was pre-configured into a slurry with a specific gravity of 1.55 g / cm 3 Desulfurization gypsum 140 parts, slag 700 parts, ordinary Portland cement 120 parts, and polycarboxylic acid water reducing agent 1 part. After mechanical stirring for 5 minutes, each sample was manually poured and tamped, and the compressive strength test piece was subjected to standard curing. The properties of Example 3 are shown in Table 4.

[0060]

[0061] Table 4

[0062] In the SGCX08 bid of the Ningbo-Cixi City (suburban) railway project, the shield interval from Jiulong Avenue Station to Yongmao West Road Station, the field application of the slurry of Example 2 was carried out. The test section of Example 2 is left line 1320-1420 ring. The ground settlement detection points of the material in Comparative Example 1 are arranged at left line 1075 ring, and the specific arrangement is shown in Figure 2 The ground settlement detection points of Example 2 are arranged at left line 1375 ring, and the specific arrangement is shown in Figure 3 The monitoring data of the surface subsidence of the grouting interval position of the material of Comparative Example 1 and Example 2 is shown in Figure 4

[0063] ​The industrial solid waste-based high-fluidity solidified sludge liquid and the preparation method thereof are described in detail above, and the principles and implementation manners of the present application are described by using specific examples. The above examples are only used to help understand the method of the present application and its core idea. Meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation manners and application ranges will be changed, and the above description should not be understood as a limitation on the present application.

Claims

1. A method for preparing a highly fluid solidified sludge slurry based on industrial solid waste, characterized in that: The method comprises: Mix the slag with water to a specific gravity of 1.45-1.6g / cm 3 of mud; Adding an industrial solid waste-based curing agent to the slurry at a rate of 10% to 30% by weight of the slurry, stirring for 5 minutes, and then pumping the resulting slurry into a slurry storage tank; Among them, the slag is the cut waste generated by shield construction, and the mass fraction of the raw materials of the industrial solid waste-based curing agent is: 100-200 parts of desulfurized gypsum powder, 600-700 parts of slag powder, 100-200 parts of ordinary Portland cement, 50-100 parts of first-class fly ash, and 1-4 parts of polycarboxylic acid water reducer.

2. The method according to claim 1, characterized in that The industrial solid waste-based curing agent raw materials are mixed by a dry powder mixer.

3. The method according to claim 2, characterized in that The slag powder is a high-activity slag powder with a particle size of ≤100 nanometers.

4. The method according to claim 3, characterized in that The desulfurized gypsum powder has a hemihydrate gypsum content of ≥85% and a chloride ion content of ≤0.01%.

5. The method according to claim 4, characterized in that The activity index of the slag powder is: 7d≥75%, 28d≥95%.

6. The method according to claim 5, characterized in that The industrial solid waste-based curing agent further comprises 0.3-1 parts of sulphoaluminate cement and 0.05 parts of an organosilicon water repellent.

7. The method according to claim 6, characterized in that 0.1-0.5 parts of a viscosity modifier is further added to the slurry, wherein the viscosity modifier is hydroxypropyl methylcellulose.

8. An industrial solid waste-based highly fluid solidified sludge slurry, produced by the method according to claims 1-7.

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