Grouting material for gypsum / glauber's salt karst foundation and preparation method and application thereof

Abstract

The present invention provides a grouting material for gypsum / glauber's salt karst foundations, a preparation method, and an application thereof. The grouting material for gypsum / glauber's salt karst foundations comprises the following components by weight: 70 to 92 parts blast furnace slag powder, 8 to 30 parts steel slag powder, and 250 to 350 parts water. The blast furnace slag powder and steel slag powder of the grouting material provided by the present invention undergo high-temperature melting and rapid cooling during their formation, resulting in a relatively dense and stable structure. This structural stability prevents hydration reactions with water. When the grouting material reaches an environment containing gypsum / glauber's salt, the calcium oxide and aluminum oxide in the blast furnace slag powder and steel slag powder react with sulfate ions in the gypsum / glauber's salt to form ettringite, which adheres to the gypsum / glauber's salt interlayer, thereby blocking dissolution and improving the stability of the gypsum / glauber's salt karst foundation.

Description

Technical Field

[0001] The present invention relates to the technical field of grouting materials, and in particular to a grouting material for gypsum / glauber's salt karst foundation, and a preparation method and application thereof. Background Art

[0002] Gypsum and thenardite, the primary representatives of sulfate rocks, are widely distributed across many regions of the world, particularly in southwestern China, where extensive thin layers of thenardite / gypsum deposits have been discovered in strata such as Sichuan Province. Due to their solubility, these rocks are susceptible to dissolution under the influence of groundwater and other corrosive currents, forming complex karst landforms, including caves, gullies, and erosion funnels. These karst formations not only affect groundwater quality but also pose a serious threat to the safety of engineering projects. Problems such as unstable foundations, collapses, water inrush, and leakage are common, posing significant challenges to construction.

[0003] With the continuous advancement of modern engineering technology, the requirements for foundation stability and bearing capacity are increasing, particularly in the construction of large-scale infrastructure projects such as high-rise buildings, bridges, and tunnels. However, the dissolution of gypsum / glauber's salt karst foundations has become a major obstacle to the smooth implementation of these projects. Traditional foundation treatment methods, such as grouting and pile reinforcement, can improve the bearing capacity of the foundation to a certain extent, but they are limited in their effectiveness in preventing the dissolution of gypsum / glauber's salt and are often costly and complex to implement.

[0004] Therefore, it is particularly important to have a gypsum / glauber's salt karst foundation corrosion blocking material. Summary of the Invention

[0005] The purpose of the present invention is to solve the technical problem of unstable foundation caused by the dissolution phenomenon of existing gypsum / glauber's salt karst ground.

[0006] To solve the above technical problems, the present invention first provides a grouting material for gypsum / glauber's salt karst foundation, which at least includes the following components in parts by mass: 70-92 parts of blast furnace slag powder, 8-30 parts of steel slag powder, and 250-350 parts of water.

[0007] Preferably, the granulation grade of blast furnace slag powder is ≥ S75, and the density of blast furnace slag powder is ≥ 2.8 g / cm 3 , specific surface area ≥300m 2 / kg.

[0008] Preferably, the granulation grade of the steel slag powder is ≥ grade II, and the fineness of the steel slag powder is not less than 1200 mesh.

[0009] Preferably, the grouting material further comprises 5 to 10 parts of an alkaline activator.

[0010] Preferably, the alkaline activator is at least one of water glass, sodium hydroxide and quicklime.

[0011] Preferably, the grouting material further comprises 3 to 5 parts of an expansion hardener and 1 to 2 parts of a stabilizer.

[0012] Preferably, the expansion hardening agent is magnesium oxide, and the stabilizer is cellulose ether compound or polyvinyl alcohol.

[0013] Accordingly, the present invention also provides a method for preparing a grouting material for a gypsum / glauber's salt karst foundation as described above, the method comprising:

[0014] S10, mixing blast furnace slag powder and steel slag powder and grinding them to obtain a powder material;

[0015] S20, mixing the powder material with water and stirring to obtain a grouting material.

[0016] Accordingly, in step S20, the stirring temperature of the stirring process is 20° C. to 30° C., and the stirring time of the stirring process is 2 to 4 minutes.

[0017] Correspondingly, the present invention further provides a grouting material for gypsum / glauber's salt karst foundation as described above and / or a preparation method for a grouting material for gypsum / glauber's salt karst foundation as described above, and their application in gypsum / glauber's salt karst foundation reinforcement projects.

[0018] The beneficial effects of the present invention are as follows: Different from the prior art, the present invention provides a grouting material for gypsum / glauber's salt karst foundation, its preparation method and application, and the grouting material for gypsum / glauber's salt karst foundation comprises at least the following components by mass: 70 to 92 parts of blast furnace slag powder, 8 to 30 parts of steel slag powder, and 250 to 350 parts of water. The blast furnace slag powder and steel slag powder of the grouting material provided by the present invention undergo high-temperature melting and rapid cooling during the formation process, making their structures relatively dense and stable. This structural stability avoids hydration reaction with water; when the grouting material reaches an environment with gypsum / glauber's salt, the calcium oxide and aluminum oxide in the blast furnace slag powder and steel slag powder can react with the sulfate ions in the gypsum / glauber's salt to form calcium sulfate and adhere to the gypsum / glauber's salt interlayer, thereby achieving the effect of blocking dissolution, thereby improving the stability of the gypsum / glauber's salt karst foundation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A flow chart of a method for preparing a grouting material for a gypsum / glauber's salt karst foundation provided by an embodiment of the present invention;

[0020] Figure 2 Schematic diagram of a gypsum / glauber's salt sandwich core sample provided by various embodiments of the present invention;

[0021] Figure 3a A schematic diagram of a core sample after the grouting material provided in some embodiments of the present invention is injected into a dynamic water test chamber containing a gypsum / glauber's salt sandwich core sample and then taken out 72 hours later;

[0022] Figure 3b Schematic diagram of a core sample taken out 72 hours after the grouting material provided in Comparative Example 2 of the present invention was injected into a dynamic water test chamber containing a gypsum / glauber's salt sandwich core sample;

[0023] Figure 4a Schematic diagram of the equipment used for performing dynamic water scouring tests on the specimens provided in Examples 1 to 6 and Comparative Examples 1 and 2 of the present invention;

[0024] Figure 4b Schematic diagram of the core sample of the test piece provided in Example 3 of the present invention after a 14-day dynamic water scour test;

[0025] Figure 4c This is a schematic diagram of the core sample of the test piece provided in Comparative Example 1 of the present invention after a 14-day dynamic water scour test;

[0026] Figure 4d This is a schematic diagram of the core sample of the test piece provided in Comparative Example 2 of the present invention after a 14-day dynamic water scour test;

[0027] Figure 4e Schematic diagram of the core sample of the test piece provided in Example 3 of the present invention after 22 days of dynamic water scour test;

[0028] Figure 4f Schematic diagram of the core sample of the specimen provided in Control Example 2 of the present invention after 22 days of dynamic water scour test. DETAILED DESCRIPTION

[0029] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] In response to the technical problem that the existing gypsum / glauber's salt karst foundation dissolution leads to unstable foundation, the present invention provides a grouting material for gypsum / glauber's salt karst foundation and its preparation method and application. The material has the advantages of good flow and permeability, no hydration ability in the absence of gypsum / glauber's salt, can target and block the dissolution of gypsum / glauber's salt, and is low in price.

[0031] In order to achieve the above technical objectives, this application adopts the following technical solutions:

[0032] In a first aspect, the present invention first provides a grouting material for gypsum / glauber's salt karst foundation, comprising at least the following components in parts by mass: 70 to 92 parts of blast furnace slag powder, 8 to 30 parts of steel slag powder, and 250 to 350 parts of water.

[0033] In the embodiment of the present invention, blast furnace slag powder is a potential hydraulic cementitious material. Experimental studies have shown that its activity changes with the change of its grinding fineness (specific surface area). When the specific surface area of ​​the grinding reaches 300m 2 / kg or above, the effect is better, which can significantly improve the early strength and the later strength can exceed that of silicate cement.

[0034] Specifically, the blast furnace slag powder adopts S75 pure slag powder that meets the standard of GB / T18046-2008 "Slag powder for cement and concrete". The density of blast furnace slag powder is ≥2.8g / cm 3 , specific surface area ≥300m 2 / kg.

[0035] Preferably, the blast furnace slag powder includes the following components in parts by mass: 30-40 parts of SiO2, 10-20 parts of Al2O3, 30-45 parts of CaO, 5-15 parts of MgO, and 1-5 parts of Fe2O3.

[0036] Steel slag powder is hot, smoldering slag. The open-hearth steelmaking process melts the charge at high temperatures into two immiscible liquid phases, separating the steel from other impurities to form steel slag powder. The activity of the free calcium oxide in the steel slag powder increases with decreasing slag fineness. Steel slag powder exhibits a certain degree of micro-expansion, which improves the shrinkage of cementitious materials.

[0037] Specifically, the granulation grade of the steel slag powder is ≥ Grade II, and the fineness of the steel slag powder is not less than 1200 meshes.

[0038] Preferably, the steel slag powder includes the following components in parts by mass: 10-30 parts of SiO2, 2-10 parts of Al2O3, 30-50 parts of CaO, 5-15 parts of MgO, and 10-30 parts of Fe2O3.

[0039] In the embodiment of the present invention, since the fineness of steel slag powder is relatively low and the glass structure of blast furnace slag powder is more stable than that of steel slag powder, this structural stability makes it easier for steel slag powder to react with sulfate ions in the gypsum / glauber's salt karst foundation to form ettringite; therefore, by adding a certain proportion of steel slag powder to the grouting material, it is beneficial to accelerate the formation of ettringite on the gypsum / glauber's salt interlayer, thereby achieving a targeted blocking effect of the dissolution of gypsum / glauber's salt and improving its anti-corrosion performance.

[0040] Specifically, when the slag powder content in the grout exceeds 30 parts per million, the formation of ettringite on the gypsum / glauber's salt interlayer is too rapid. Rapid ettringite formation can have multiple impacts on the grout's performance. On the one hand, excessively rapid formation can lead to unstable ettringite crystal structures, making it difficult to form an effective barrier layer on the gypsum / glauber's salt interlayer. On the other hand, an overly rapid reaction can lead to localized uneven reaction, compromising the stability and durability of the entire grout system.

[0041] Specifically, when the amount of steel slag powder in the grouting material is less than 8 parts, the rate of formation of calcium aluminate on the gypsum / glauber's salt interlayer is slow. When the steel slag powder content is too low, the substances participating in the reaction are relatively reduced, and the driving force of the reaction is insufficient, which slows down the rate of formation of calcium aluminate on the gypsum / glauber's salt interlayer. The slow formation of calcium aluminate will bring a series of problems. First, an effective protective layer cannot be formed on the interlayer in time, and the dissolution of gypsum and Glauber's salt cannot be blocked in time, which may cause the damage to the structure to gradually increase. Secondly, the slow reaction speed may affect the progress and efficiency of the entire grouting project and prolong the construction time.

[0042] In an embodiment of the present invention, the grouting material also includes 5 to 10 parts of an alkaline activator. The alkaline activator primarily promotes the reaction of active ingredients in the material by providing an alkaline environment. Under alkaline conditions, elements such as silicon and aluminum in the material react chemically with alkali metal ions to form a gelling product.

[0043] Specifically, the alkaline activator can promote the dissolution of silicon-calcium-aluminum substances in blast furnace slag powder and steel slag powder, thereby accelerating the reaction of silicon-calcium-aluminum substances with sulfate ions in gypsum / glauber's salt karst foundation to form ettringite.

[0044] Preferably, the alkaline activator is at least one of water glass, sodium hydroxide and quicklime.

[0045] In an embodiment of the present invention, the grouting material also includes 3 to 5 parts of an expansive hardener and 1 to 2 parts of a stabilizer; wherein the expansive hardener can fill the tiny gaps and cracks between the grouting material and the injected structure, thereby improving the overall density and enhancing the waterproof and anti-seepage properties; the stabilizer can prevent the grouting material from undergoing performance changes during storage, transportation and use, such as precipitation, stratification, deterioration, etc., thereby ensuring that the grouting material always maintains good working performance.

[0046] Preferably, the expansion hardening agent is magnesium oxide, and the stabilizer is cellulose ether compound or polyvinyl alcohol.

[0047] See also Figure 1 , Figure 1 A flow chart of a method for preparing a grouting material for a gypsum / glauber's salt karst foundation provided in an embodiment of the present invention; wherein the method comprises:

[0048] S10, mixing blast furnace slag powder and steel slag powder and grinding them to obtain a powder material;

[0049] S20, mixing the powder material with water and stirring to obtain a grouting material.

[0050] Specifically, in step S10, the blast furnace slag powder and the steel slag powder are mixed evenly using a mixer, and then ground using a ball mill.

[0051] In step S20, the stirring temperature of the stirring treatment is 20° C. to 30° C., and the stirring time of the stirring treatment is 2 to 4 minutes.

[0052] Accordingly, the present invention further provides a grouting material for gypsum / glauber's salt karst foundation as described above and / or a preparation method for a grouting material for gypsum / glauber's salt karst foundation as described above, and its application in a gypsum / glauber's salt karst foundation reinforcement project; wherein the mechanism by which the grouting material can have good anti-corrosion performance in a gypsum / glauber's salt karst environment is as follows:

[0053] Since both blast furnace slag powder and steel slag powder contain CaO and Al2O3, and while they have some potential activity, they are essentially inert to hydration reactions in water alone. Therefore, in the absence of gypsum / salt-salt, the material can diffuse with the water flow without losing its active ingredients due to hydration reactions.

[0054] When the above grouting material reaches the environment with gypsum / glauber's salt, it can generate ettringite and adhere to the gypsum / glauber's salt interlayer. The specific reaction is as follows:

[0055] 6CaO+Al2O3+3CaSO4+61H2O=3CaO·Al2O3·3CaSO4·32H2O+29H2O.

[0056] Because ettringite is CaO, Al2O3 and SO4 2- The reaction generates SO4 in the environment 2－ It will not corrode the newly formed ettringite, thus achieving the effect of blocking dissolution.

[0057] The technical solution of the present invention will now be further described with reference to specific embodiments.

[0058] 1. Test methods for various embodiments and comparative examples

[0059] Example 1:

[0060] This embodiment 1 provides a grouting material for gypsum / glauber's salt karst foundation, comprising the following components in parts by mass: 95 parts of blast furnace slag powder, 5 parts of steel slag powder, and 300 parts of water; wherein the blast furnace slag powder is 800 mesh S95 grade granulated blast furnace slag, and the steel slag powder is 1200 mesh Grade II steel slag powder.

[0061] Example 2:

[0062] This embodiment 2 provides a grouting material for gypsum / glauber's salt karst foundation, comprising the following components in parts by mass: 92 parts of blast furnace slag powder, 8 parts of steel slag powder, and 300 parts of water; wherein the blast furnace slag powder is 800 mesh S95 grade granulated blast furnace slag, and the steel slag powder is 1200 mesh Grade II steel slag powder.

[0063] Example 3:

[0064] This embodiment 3 provides a grouting material for gypsum / glauber's salt karst foundation, comprising the following components in parts by mass: 90 parts of blast furnace slag powder, 10 parts of steel slag powder, and 300 parts of water; wherein the blast furnace slag powder is 800 mesh S95 grade granulated blast furnace slag, and the steel slag powder is 1200 mesh Grade II steel slag powder.

[0065] Example 4:

[0066] This embodiment 4 provides a grouting material for gypsum / glauber's salt karst foundation, comprising the following components in parts by mass: 85 parts of blast furnace slag powder, 15 parts of steel slag powder, and 300 parts of water; wherein the blast furnace slag powder is 800 mesh S95 grade granulated blast furnace slag, and the steel slag powder is 1200 mesh Grade II steel slag powder.

[0067] Example 5:

[0068] This embodiment 5 provides a grouting material for gypsum / glauber's salt karst foundation, comprising the following components in parts by mass: 80 parts of blast furnace slag powder, 20 parts of steel slag powder, and 300 parts of water; wherein the blast furnace slag powder is 800 mesh S95 grade granulated blast furnace slag, and the steel slag powder is 1200 mesh Grade II steel slag powder.

[0069] Example 6:

[0070] This embodiment 6 provides a grouting material for gypsum / glauber's salt karst foundation, comprising the following components in parts by mass: 75 parts of blast furnace slag powder, 25 parts of steel slag powder, and 300 parts of water; wherein the blast furnace slag powder is 800 mesh S95 grade granulated blast furnace slag, and the steel slag powder is 1200 mesh Grade II steel slag powder.

[0071] Comparative Example 1:

[0072] Comparative Example 1 provides a grouting material for a gypsum / glauber's salt karst foundation, comprising 400 parts by mass of clean water.

[0073] Comparative Example 2:

[0074] Comparative Example 2 provides a grouting material for gypsum / glauber's salt karst foundation, including 400 parts by mass of PO42.5 cement paste (water-cement ratio 1:1), where the PO42.5 cement paste is a slurry formed by mixing PO42.5 ordinary Portland cement and water.

[0075] II. Analysis of test results of various embodiments and comparative examples

[0076] The grouting materials prepared in Examples 1 to 6 and Comparative Examples 1 to 2 were injected into a dynamic water test box containing a gypsum / glauber's salt sandwich core sample for 4 hours. Afterwards, the SO4 content of each test box was tested at intervals of 24 hours. 2- concentration, conductivity; until SO4 in all examples 2－ After the temperature is 0, Examples 1 to 6 and Comparative Example 2 are cleaned.

[0077] See also Figure 2 、 Figure 3a as well as Figure 3b , Figure 2 Schematic diagram of a gypsum / glauber's salt sandwich core sample provided by various embodiments of the present invention; Figure 3a A schematic diagram of a core sample after the grouting material provided in some embodiments of the present invention is injected into a dynamic water test chamber containing a gypsum / glauber's salt sandwich core sample and then taken out 72 hours later; Figure 3b Schematic diagram of the core sample taken out 72 hours after the grouting material provided in comparative example 2 of the present invention was injected into a dynamic water test box containing a gypsum / glauber's salt sandwich core sample; Figure 3a as well as Figure 3b It can be seen that the core samples of Examples 1 to 6 are all covered with a thick layer of gypsum / glauber's salt karst foundation dissolution blocking material (ettringite), while the cement slurry of Control Example 2 completely fills the entire test box and is processed into a cylindrical core sample.

[0078] See also Figure 4a , Figure 4a Schematic diagram of the equipment used for the dynamic water scouring test of the specimens provided in Examples 1 to 6 of the present invention and Comparative Examples 1 to 2; the same SO4 as in Comparative Example 1 was used. 2- The cylindrical core samples formed after the tests of Examples 1 to 6 and Control Example 2 in the dynamic water test chamber were subjected to a dynamic water scouring test with a concentration solution. The respective dissolution amounts were recorded every 24 hours. After 24 hours, the dissolution amount of Control Example 1 was no longer tested. The state of the specimens was observed. Figure 4b to Figure 4f As shown, Figure 4b Schematic diagram of the core sample of the test piece provided in Example 3 of the present invention after a 14-day dynamic water scour test; Figure 4c This is a schematic diagram of the core sample of the test piece provided in Comparative Example 1 of the present invention after a 14-day dynamic water scour test; Figure 4dThis is a schematic diagram of the core sample of the test piece provided in Comparative Example 2 of the present invention after a 14-day dynamic water scour test; Figure 4e Schematic diagram of the core sample of the test piece provided in Example 3 of the present invention after 22 days of dynamic water scour test; Figure 4f Schematic diagram of the core sample of the specimen provided in Control Example 2 of the present invention after 22 days of dynamic water scour test.

[0079] Specifically, by Figure 4b to Figure 4f It can be seen that the cylindrical core samples of the specimens provided in Example 3 of the present invention after the 14d and 22d dynamic water scouring tests were all covered with a thick layer of gypsum / glauber's salt karst foundation dissolution blocking material, and no dissolution occurred. The specimens provided in Control Example 1 of the present invention all showed obvious dissolution after the 14d dynamic water scouring test.

[0080] Please refer to Table 1 below, which shows the dissolution results of the test pieces provided in Examples 1 to 6 and Comparative Examples 1 to 2 of the present invention after the dynamic water scouring test:

[0081] Table 1

[0082]

[0083] Specifically, it can be seen from Table 1 that the dissolution amount of the cylindrical core sample of Control Example 1 after the dynamic water scouring test after 24 hours of dynamic water scouring is 23%, indicating that obvious dissolution occurs; the cylindrical core samples of Examples 1 to 6 after the dynamic water scouring test are all covered with a thick layer of gypsum / glauber's salt karst foundation dissolution blocking material, and the dissolution amount after 24 hours of dynamic water scouring is 0, and the structure of the cylindrical core sample after the dynamic water scouring test is stable, indicating that they all have good dissolution performance, can remain stable for a long time in the groundwater environment, and effectively prevent the dissolution and migration of gypsum and Glauber's salt.

[0084] Furthermore, it can be seen from Table 1 that the cylindrical core samples formed by injecting PO42.5 cement slurry with a water-cement ratio of 1:1 into the gypsum / glauber's salt interlayer in Control Example 2 showed a dissolution rate of 0 after a 24-hour dynamic water scouring test, indicating that Control Example 2 also has a certain dissolution performance on the gypsum / glauber's salt interlayer. This is mainly because the main components of PO42.5 cement, such as tricalcium silicate, dicalcium silicate, and tricalcium aluminate, will undergo hydration reactions in a water environment. When sulfate ions are present in the environment, sulfate ions will react with calcium hydroxide in the cement to form calcium sulfate, and calcium sulfate may further react with tricalcium aluminate in the cement to form calcium sulfonite. However, the formation of calcium sulfonite will cause the volume expansion of the cement, causing cracking and damage to the cylindrical core samples, which is not conducive to the stability of the foundation of the gypsum / glauber's salt interlayer. Figure 4d as well as Figure 4f shown.

[0085] The grouting material for gypsum / glauber's salt karst foundations provided by the embodiments of the present invention exhibits excellent corrosion resistance and can maintain long-term stability in groundwater environments. It effectively prevents the dissolution and migration of gypsum and glauber's salt, thereby blocking the corrosion effects of gypsum and glauber's salt, thereby improving the stability and bearing capacity of the karst foundation. Furthermore, the material should exhibit good construction performance, facilitate application in complex and variable karst foundation environments, and be cost-effective and economically viable.

[0086] The grouting material for gypsum / salt-repellent karst foundation provided by the embodiment of the present invention has good flow and permeability, has no hydration ability in the absence of gypsum / salt-repellent, and only has the ability to hydrate in the presence of SO4 2－ Hydration can only occur in a suitable environment, which can target and block the dissolution of gypsum / saltrock, and it is inexpensive. Furthermore, the main components of the grouting material are solid powders. Before use, only water needs to be added and mixed to obtain the desired grouting material. No activator solution needs to be prepared in advance, which has the advantages of simple process and convenient construction.

[0087] Compared with other existing methods, the benefits of the present invention include:

[0088] (1) Compared with the existing barrier method, the design is more difficult and requires regular maintenance. However, the corrosion blocking treatment using the present invention is simple and easy, has good durability, excellent corrosion resistance, and does not require regular maintenance.

[0089] (2) The pile-repair method requires the pile to pass through the gypsum layer, which has a high processing cost. However, the present invention can react the gypsum interlayer in the rock layer and block the progress of dissolution, so the cost is lower.

[0090] (3) Compared with the existing treatment technology, the present invention has the characteristics of low cost, targeted treatment, and green environmental protection. It can effectively and economically block the dissolution reaction and fundamentally solve the dissolution problem of gypsum interlayer.

[0091] In summary, different from the prior art, the present invention provides a grouting material for gypsum / glauber's salt karst foundation and its preparation method and application. The grouting material for gypsum / glauber's salt karst foundation comprises at least the following components in parts by mass: 70 to 92 parts of blast furnace slag powder, 8 to 30 parts of steel slag powder, and 250 to 350 parts of water. The blast furnace slag powder and steel slag powder of the grouting material provided by the present invention undergo high-temperature melting and rapid cooling during the formation process, making their structure relatively dense and stable. This structural stability avoids hydration reaction with water; when the grouting material reaches an environment with gypsum / glauber's salt, the calcium oxide and aluminum oxide in the blast furnace slag powder and the steel slag powder can react with the sulfate ions in the gypsum / glauber's salt to form calcium aluminate and adhere to the gypsum / glauber's salt interlayer, thereby achieving the effect of blocking dissolution, thereby improving the stability of the gypsum / glauber's salt karst foundation.

[0092] It should be noted that the above embodiments all belong to the same inventive concept, and the description of each embodiment has its own focus. For any details not described in individual embodiments, reference may be made to the description in other embodiments.

[0093] The above embodiments merely illustrate the implementation methods of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A grouting material for gypsum / glauber's salt karst foundation, characterized in that: The grouting material is composed of the following components in parts by mass: 70-92 parts of blast furnace slag powder, 8-30 parts of steel slag powder, and 250-350 parts of water. The granulation grade of the blast furnace slag powder is ≥ S75, and the density of the blast furnace slag powder is ≥ 2.8 g / cm 3 , specific surface area ≥300m 2 / kg, the granulation grade of the steel slag powder is ≥ Grade II, and the fineness of the steel slag powder is not less than 1200 mesh; When the grouting material reaches an environment with gypsum / glauber's salt, calcium oxide and aluminum oxide in the blast furnace slag powder and the steel slag powder can react with sulfate ions in the gypsum / glauber's salt to form ettringite and adhere to the gypsum / glauber's salt interlayer.

2. A grouting material for gypsum / glauber's salt karst foundation, characterized in that: The grouting material is composed of the following components in parts by mass: 70-92 parts of blast furnace slag powder, 8-30 parts of steel slag powder, 250-350 parts of water, 3-5 parts of expansion hardener, and 1-2 parts of stabilizer; the granulation grade of the blast furnace slag powder is ≥ S75, and the density of the blast furnace slag powder is ≥ 2.8g / cm 3 , specific surface area ≥300m 2 / kg, the granulation grade of the steel slag powder is ≥ Grade II, and the fineness of the steel slag powder is not less than 1200 mesh; When the grouting material reaches an environment with gypsum / glauber's salt, calcium oxide and aluminum oxide in the blast furnace slag powder and the steel slag powder can react with sulfate ions in the gypsum / glauber's salt to form ettringite and adhere to the gypsum / glauber's salt interlayer.

3. The grouting material for gypsum / glauber's salt karst foundation according to claim 2, characterized in that: The expansion hardening agent is magnesium oxide, and the stabilizer is cellulose ether compound or polyvinyl alcohol.

4. A method for preparing a grouting material for gypsum / glauber's salt karst foundation according to claim 1, characterized in that: The method comprises: S10, mixing blast furnace slag powder and steel slag powder and grinding them to obtain a powder material; S20, mixing the powder material with water and stirring to obtain a grouting material.

5. The method for preparing a grouting material for gypsum / glauber's salt karst foundation according to claim 4, characterized in that: In the step S20, the stirring temperature of the stirring process is 20° C. to 30° C., and the stirring time of the stirring process is 2 to 4 minutes.

6. Use of the grouting material for gypsum / glauber's salt karst foundation according to claim 1 or 2 and / or the preparation method of the grouting material for gypsum / glauber's salt karst foundation according to any one of claims 4 to 5 in gypsum / glauber's salt karst foundation reinforcement projects.

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