Anti-freezing and thawing soft soil curing agent and preparation method thereof

Abstract

The application relates to an anti-freezing and thawing soft soil curing agent and a preparation method thereof, and relates to the technical field of curing materials.The preparation method of the anti-freezing and thawing soft soil curing agent comprises the following steps: mixing and crushing coal gangue, titanium gypsum and water-based drilling cuttings to obtain a mixture; and alternately and circularly treating the mixture by magnetic field heat treatment and freezing treatment in sequence to obtain the anti-freezing and thawing soft soil curing agent; wherein the weight ratio of the coal gangue, the titanium gypsum and the water-based drilling cuttings is (17-24):(4-8):(10-15). The application uses coal gangue, titanium gypsum and water-based drilling cuttings in a suitable proportion as raw materials, and combines magnetic field heat treatment and freezing treatment to realize the significant improvement of the compression strength and the anti-freezing and thawing capacity of the cured soft soil, promotes the resource utilization of solid waste, meets the green environmental protection requirement of treating waste with waste, and has important technical value and environmental protection significance.

Description

Technical Field

[0001] This invention relates to the field of solidification materials technology, and in particular to a freeze-thaw resistant soft soil solidifier and its preparation method. Background Technology

[0002] To overcome the shortcomings of traditional solidifying agents, researchers are actively exploring new development paths for solidifying agents. Among these, the preparation of high-performance solidifying agents using industrial waste and natural materials has become a research hotspot. For example, solidifying agents with excellent properties have been prepared using industrial wastes such as slag, fly ash, and desulfurized gypsum through physical, chemical, or composite modification methods. These solidifying agents can not only effectively improve the strength and stability of soft soil but also realize the resource utilization of industrial waste, reducing environmental pollution. However, although these new solidifying agents have made some progress in strength improvement, they still have certain limitations in freeze-thaw resistance, especially in extremely cold regions where the moisture in the soil undergoes significant volume changes during repeated freeze-thaw cycles, damaging the solidified soil structure and failing to meet user needs. Summary of the Invention

[0003] To address the above problems, this invention provides an antifreeze-thaw soft soil solidifying agent and its preparation method.

[0004] The technical solution provided by this invention is as follows:

[0005] In a first aspect, the present invention provides a method for preparing a freeze-thaw resistant soft soil solidifying agent, the method comprising the following steps:

[0006] Coal gangue, titanium gypsum, and water-based drilling cuttings are mixed and crushed to obtain a mixture.

[0007] The mixture is subjected to alternating cycles of magnetic field heat treatment and freezing treatment to obtain the freeze-thaw resistant soft soil solidifier.

[0008] The weight ratio of the coal gangue, titanium gypsum and water-based drilling cuttings is (17-24):(4-8):(10-15).

[0009] Furthermore, the weight ratio of the coal gangue, titanium gypsum, and water-based drilling cuttings is 20:6:13.

[0010] Furthermore, the particle size of the mixture is 100-200 mesh.

[0011] Furthermore, the operating conditions parameters for the magnetic field heat treatment include: magnetic flux coil current of 5-10A, magnetic field heat treatment temperature of 280-360℃, and magnetic field heat treatment time of 10-20 minutes.

[0012] Furthermore, the operating conditions parameters for the magnetic field heat treatment include: a magnetic flux coil current of 7A, a magnetic field heat treatment temperature of 335℃, and a magnetic field heat treatment time of 10–20 minutes.

[0013] Furthermore, the freezing temperature is -50℃ to -40℃.

[0014] Furthermore, the freezing process takes 15 to 25 minutes.

[0015] Furthermore, the alternating cyclic processing is performed 4 to 8 times.

[0016] In a second aspect, the present invention provides a freeze-thaw resistant soft soil solidifier, which is prepared by any of the preparation methods described in the first aspect.

[0017] The technical solutions provided in the embodiments of the present invention have at least the following advantages compared with the prior art:

[0018] This invention provides a freeze-thaw resistant soft soil solidifier and its preparation method. Using coal gangue, titanium gypsum, and water-based drilling cuttings in appropriate proportions as raw materials, and combining a combined alternating cycle of magnetic field heat treatment and freeze treatment, this invention significantly improves the compressive strength and freeze-thaw resistance of the solidified soft soil. It also promotes the resource utilization of solid waste, achieving the green and environmentally friendly requirement of treating waste with waste, and has significant technical value and environmental significance. Specifically:

[0019] 1) On the one hand, this invention uses coal gangue as the main active ingredient source of the solidifying agent. Its high content of silicon, aluminum, and other oxides can form stable cementing mineral phases such as calcium silicate and aluminosilicate during the hydration reaction, ensuring the strength of the solidified soil. The calcium sulfate dihydrate contained in titanium gypsum not only has filling properties, filling the gaps between soil particles and improving the density of the solidified soil, but also reacts chemically with the components in coal gangue to generate more stable mineral phases. At the same time, the appropriate addition of titanium gypsum can also adjust the pH value of the solidified soil, which is conducive to the hydration reaction. Water-based drilling cuttings play a regulating role. They contain a certain amount of clay minerals and quartz, which can improve the gradation of soil particles, making the soil particles more evenly distributed, thereby improving the stability and workability of the solidified soil and making the solidification process easier to control.

[0020] Therefore, by setting the above-mentioned suitable weight ratio, the present invention achieves complementary advantages among coal gangue, titanium gypsum, and water-based drilling cuttings. Coal gangue provides the main active ingredients and strength source; titanium gypsum enhances the compactness and stability of the solidified soil through filling, pH adjustment, and synergistic reaction; and water-based drilling cuttings improve the gradation of soil particles and the workability of the solidified soil, laying a good foundation for the subsequent solidification process.

[0021] 2) On the other hand, this invention employs an alternating cycle of magnetic field heat treatment and freezing treatment. Magnetic field heat treatment primarily promotes chemical reactions and the activation of mineral activity, while freezing treatment causes the material to break down, optimizing the particle structure and facilitating the formation of a more stable mineral phase network during subsequent solidification. This alternating cycle of treatment not only promotes the optimization of the internal structure of the raw material and the deepening of chemical reactions under different physical fields, but also achieves a significant improvement in the compressive strength and freeze-thaw resistance of the solidified soft soil through repeated cumulative effects, achieving a synergistic effect of "1+1>2". Simultaneously, the entire preparation process is relatively mild, avoiding the problems of high energy consumption inherent in traditional high-temperature activation. Attached Figure Description

[0022] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 A flowchart illustrating the preparation method of the freeze-thaw resistant soft soil solidifying agent provided by the present invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0027] In a first aspect, the present invention provides a method for preparing an antifreeze-thaw soft soil solidifying agent, such as... Figure 1 As shown, the preparation method of the freeze-thaw resistant soft soil solidification agent includes the following steps:

[0028] Coal gangue, titanium gypsum, and water-based drilling cuttings are mixed and crushed to obtain a mixture.

[0029] The mixture is subjected to alternating cycles of magnetic field heat treatment and freezing treatment to obtain the freeze-thaw resistant soft soil solidifier.

[0030] The weight ratio of the coal gangue, titanium gypsum and water-based drilling cuttings is (17-24):(4-8):(10-15).

[0031] This invention provides a method for preparing a freeze-thaw resistant soft soil solidifier. The invention uses coal gangue, titanium gypsum and water-based drilling cuttings in appropriate proportions as raw materials, and combines magnetic field heat treatment and freezing treatment in an alternating cycle to significantly improve the compressive strength and freeze-thaw resistance of the solidified soft soil. It also promotes the resource utilization of solid waste and meets the green and environmentally friendly requirements of treating waste with waste, which has important technical value and environmental significance.

[0032] In this invention, coal gangue is a solid waste generated and discharged during coal mining and washing processes, and its waste code in the "Solid Waste Classification and Code Catalog" is 060-001-S04. Optionally, the main components of the coal gangue selected in this invention include Al2O3 and SiO2, with the weight percentage of Al2O3 being 21% to 30% and the weight percentage of SiO2 being 45% to 62%.

[0033] In this invention, the titanium gypsum is a type of gypsum produced during the sulfuric acid process for titanium dioxide production. It is created by adding lime (or carbide slag) to neutralize the large amount of acidic wastewater to treat the wastewater. Its waste code in the "Solid Waste Classification and Code Catalog" is 261-003-S11. Its main component is calcium sulfate dihydrate, it is solid, and its initial color is black. Optionally, the titanium gypsum selected in this invention has calcium sulfate dihydrate as its main component, with a weight percentage of 68-74%.

[0034] In this invention, water-based drilling cuttings are solid waste generated during oil and gas drilling processes, belonging to Category I general industrial solid waste under the encouraged resource utilization category. Their waste code in the "Solid Waste Classification and Code Catalog" is 071-001-S12. Optionally, the main components of the water-based drilling cuttings used in this invention include Al2O3, CaO, and SiO2, wherein the weight percentage of Al2O3 is 3.5–5%, the weight percentage of CaO is 30–33%, and the weight percentage of SiO2 is 20–24%.

[0035] In some specific embodiments, the weight ratio of the coal gangue, titanium gypsum, and water-based drilling cuttings is 20:6:13.

[0036] In some specific embodiments, the particle size of the mixture is 100-200 mesh.

[0037] In some specific embodiments, the operating conditions parameters of the magnetic field heat treatment include: magnetic flux coil current of 5-10A, magnetic field heat treatment temperature of 280-360℃, and magnetic field heat treatment time of 10-20 minutes.

[0038] In some specific embodiments, the operating conditions parameters of the magnetic field heat treatment include: magnetic flux coil current of 7A, magnetic field heat treatment temperature of 335℃, and magnetic field heat treatment time of 10 to 20 minutes.

[0039] In some specific embodiments, the freezing temperature is -50°C to -40°C, preferably -45°C.

[0040] In some specific embodiments, the freezing time is 15 to 25 minutes, preferably 20 minutes.

[0041] In some specific embodiments, the alternating cycle is performed 4 to 8 times, preferably 5 times.

[0042] Secondly, based on the same inventive concept, the present invention provides a freeze-thaw resistant soft soil solidifying agent, which is prepared by the preparation method described in any one of the first aspects.

[0043] The freeze-thaw resistant soft soil solidification provided by the present invention is achieved based on the preparation method of the freeze-thaw resistant soft soil solidification agent according to any one of the first aspects, and therefore has at least the beneficial effects of the preparation method of the freeze-thaw resistant soft soil solidification agent according to any one of the first aspects, which will not be elaborated here.

[0044] It should be noted that, unless otherwise specified or described, the raw materials involved in the freeze-thaw resistant soft soil solidifier and its preparation method provided by this invention can be directly adopted from commercially available products or made in-house according to the preparation process disclosed in the prior art; at the same time, unless otherwise specified or described, the operation steps and condition parameters involved can be carried out according to the existing soft soil solidifier preparation process or using existing equipment, and will not be described in detail in this invention document.

[0045] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed according to national standards. If no corresponding national standard exists, then generally accepted international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0046] Example 1

[0047] This example provides a freeze-thaw resistant soft soil solidifier, the preparation method of which includes the following steps:

[0048] Step (1): Mix and crush coal gangue, titanium gypsum and water-based drilling cuttings in a weight ratio of 20:6:13, and pass them through a 100-mesh sieve to obtain the first mixture;

[0049] Step (2): Place the first mixture obtained in step (1) in a magnetic heating device and perform magnetic field heat treatment for 15 minutes under the conditions of magnetic flux coil current of 7A and temperature of 335℃ to obtain the second mixture;

[0050] Step (3): Place the second mixture obtained in step (2) in a -45℃ environment for freezing treatment for 20 minutes, and then restore it to room temperature to obtain the third mixture;

[0051] Step (4): The third mixture obtained in step (3) is subjected to alternating cycles of magnetic field heat treatment in step (2) and freezing treatment in step (3) for a total of 5 cycles to obtain the freeze-thaw resistant soft soil solidifying agent.

[0052] Example 2

[0053] This example provides a freeze-thaw resistant soft soil solidifier, the preparation method of which includes the following steps:

[0054] Step (1): Mix and crush coal gangue, titanium gypsum and water-based drilling cuttings in a weight ratio of 17:4:10, and pass them through a 100-mesh sieve to obtain the first mixture;

[0055] Step (2): Place the first mixture obtained in step (1) in a magnetic heating device and perform magnetic field heat treatment for 10 minutes under the conditions of magnetic flux coil current of 5A and temperature of 360℃ to obtain the second mixture;

[0056] Step (3): Place the second mixture obtained in step (2) in a -40℃ environment for freezing treatment for 25 minutes, and then restore it to room temperature to obtain the third mixture;

[0057] Step (4): The third mixture obtained in step (3) is subjected to alternating cycles of magnetic field heat treatment in step (2) and freezing treatment in step (3) for a total of 5 cycles to obtain the freeze-thaw resistant soft soil solidifying agent.

[0058] Example 3

[0059] This example provides a freeze-thaw resistant soft soil solidifier, the preparation method of which includes the following steps:

[0060] Step (1): Mix and crush coal gangue, titanium gypsum and water-based drilling cuttings in a weight ratio of 24:8:15, and pass them through a 100-mesh sieve to obtain the first mixture;

[0061] Step (2): Place the first mixture obtained in step (1) in a magnetic heating device and perform magnetic field heat treatment for 20 minutes under the conditions of magnetic flux coil current of 10A and temperature of 280℃ to obtain the second mixture;

[0062] Step (3): Place the second mixture obtained in step (2) in a -50℃ environment for freezing treatment for 15 minutes, and then restore it to room temperature to obtain the third mixture;

[0063] Step (4): The third mixture obtained in step (3) is subjected to alternating cycles of magnetic field heat treatment in step (2) and freezing treatment in step (3) for a total of 5 cycles to obtain the freeze-thaw resistant soft soil solidifying agent.

[0064] Comparative Example 1

[0065] This example provides a soft soil solidification agent and its preparation method. The only difference from Example 1 is that the combined alternating cycle of magnetic field heat treatment and freezing treatment is not performed; all other steps and parameters are the same.

[0066] The preparation method of the above-mentioned soft soil stabilizing agent includes the following steps:

[0067] Coal gangue, titanium gypsum, and water-based drilling cuttings in a weight ratio of 20:6:13 were mixed, crushed, and passed through a 100-mesh sieve to obtain the soft soil solidifying agent.

[0068] Comparative Example 2

[0069] This example provides a soft soil solidification agent and its preparation method, which differs from Example 1 only in that magnetic field heat treatment is not performed; all other steps and parameters are the same.

[0070] The preparation method of the above-mentioned soft soil stabilizing agent includes the following steps:

[0071] Step (1): Mix and crush coal gangue, titanium gypsum and water-based drilling cuttings in a weight ratio of 20:6:13, and pass them through a 100-mesh sieve to obtain the first mixture;

[0072] Step (2): Place the first mixture obtained in step (1) in a -45℃ environment for freezing treatment for 20 minutes, and then restore it to room temperature to obtain the second mixture;

[0073] Step (3): The second mixture obtained in step (2) is subjected to cyclic treatment according to the freezing treatment in step (2) for 5 cycles to obtain the freeze-thaw resistant soft soil solidifying agent.

[0074] Comparative Example 3

[0075] This example provides a soft soil stabilizer and its preparation method, which differs from Example 1 only in that: no freezing treatment is performed; all other steps and parameters are the same.

[0076] The preparation method of the above-mentioned soft soil stabilizing agent includes the following steps:

[0077] Step (1): Mix and crush coal gangue, titanium gypsum and water-based drilling cuttings in a weight ratio of 20:6:13, and pass them through a 100-mesh sieve to obtain the first mixture;

[0078] Step (2): Place the first mixture obtained in step (1) in a magnetic heating device and perform magnetic field heat treatment for 15 minutes under the conditions of magnetic flux coil current of 7A and temperature of 335℃ to obtain the second mixture;

[0079] Step (3): The second mixture obtained in step (2) is subjected to cyclic treatment according to the magnetic field heat treatment in step (2), and the number of cycles is 5, to obtain the freeze-thaw resistant soft soil solidifying agent.

[0080] Comparative Example 4

[0081] This example provides a soft soil stabilizer and its preparation method. The only difference from Example 1 is that the weight ratio of coal gangue, titanium gypsum and water-based drilling cuttings is adjusted to 1:1:1; the other steps and parameters are the same.

[0082] Comparative Example 5

[0083] This example provides a soft soil stabilizer and its preparation method. The only difference from Example 1 is that the water-based drilling cuttings are replaced with fly ash; the other steps and parameters are the same.

[0084] Test case

[0085] This example demonstrates the performance testing of the soft soil stabilizers provided in Examples 1-3 and Comparative Examples 1-5.

[0086] Test methods: 1) The soft soil solidifying agents provided in each embodiment and comparative example were mixed with soft soil at a weight ratio of 1:3, and water was added and stirred to obtain a uniform slurry with a weight percentage concentration of 65%. The slurry was poured and molded according to GB / T50123-2019 "Standard for Geotechnical Testing Methods". After demolding, the solidified soil samples were cured in a standard curing room at 20℃ and 90% humidity for 28 days, and then the unconfined compressive strength was tested. 2) The solidified soil samples after 28 days of curing were subjected to freeze-thaw cycle tests. They were first frozen at -20℃ for 4 hours, and then adjusted to 20℃ and placed for another 4 hours. This is one freeze-thaw cycle. After 15 freeze-thaw cycles, the unconfined compressive strength loss rate was tested and calculated. The lower the unconfined compressive strength loss rate, the better the freeze-thaw resistance.

[0087] The test results are shown in Table 1.

[0088] Table 1

[0089]

[0090] As shown in Table 1:

[0091] 1) Compared with comparative examples 1 to 5, the solidified soil samples obtained by using the freeze-thaw resistant soft soil solidifier provided in examples 1 to 3 of this invention have better compressive strength and freeze-thaw resistance, especially the loss rate of unconfined compressive strength is lower, maintained at about 5%, which can meet the needs of soft soil solidification in extremely cold regions.

[0092] 2) The test results of Comparative Example 1, Comparative Example 2, Comparative Example 3 and Example 1 show that the present invention adopts a combined alternating cycle of magnetic field heat treatment and freezing treatment, which has a significant synergistic effect, and achieves a significant improvement in the compressive strength and freeze-thaw resistance of the solidified soft soil, achieving a synergistic effect of "1+1>2".

[0093] 3) The test results of Comparative Example 4, Comparative Example 5 and Example 1 show that when the proportion or composition of coal gangue, titanium gypsum and water-based drilling cuttings as raw materials in this invention are adjusted, the compressive strength and freeze-thaw resistance of the obtained solidified soil samples will be significantly reduced, especially the freeze-thaw resistance.

[0094] In summary, the embodiments of the present invention provide a freeze-thaw resistant soft soil solidifier and its preparation method. By using coal gangue, titanium gypsum and water-based drilling cuttings in appropriate proportions as raw materials, and combining magnetic field heat treatment and freezing treatment in an alternating cycle, the compressive strength and freeze-thaw resistance of the solidified soft soil are significantly improved. It also promotes the resource utilization of solid waste, meets the green and environmentally friendly requirements of treating waste with waste, and has important technical value and environmental significance.

[0095] Various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is indicated herein, it means including any referenced number (fraction or integer) within the indicated range. The above description is merely a specific embodiment of the invention to enable those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for preparing an anti-freeze-thaw soft soil solidifying agent, characterized by, The preparation method of the anti-freezing and thawing soft soil curing agent comprises the following steps: The coal gangue, titanium gypsum and water-based drilling cuttings are mixed and crushed to obtain a mixture; The mixture is subjected to alternating cycle treatment of magnetic field heat treatment and freezing treatment in sequence to obtain the anti-freezing and thawing soft soil curing agent; The working condition parameters of the magnetic field heat treatment include that the magnetic flux coil current is 5-10 A, the magnetic field heat treatment temperature is 280-360 DEG C, and the magnetic field heat treatment time is 10-20 minutes; The freezing treatment temperature is -50 DEG C to -40 DEG C, the freezing treatment time is 15-25 minutes, and the number of alternating cycle treatment is 4-8 times. The weight ratio of the coal gangue, titanium gypsum and water-based drilling cuttings is 20:6:

13.

2. The method for preparing the anti-freezing and thawing soft soil solidifying agent according to claim 1, characterized in that, The particle size of the mixture is 100-200 meshes.

3. The preparation method of the freeze-thaw resistant soft soil solidifying agent according to claim 1, characterized in that, The working condition parameters of the magnetic field heat treatment include that the magnetic flux coil current is 7 A, the magnetic field heat treatment temperature is 335 DEG C, and the magnetic field heat treatment time is 10-20 minutes.

4. An anti-freeze-thaw soft soil solidifying agent, characterized by, The anti-freezing and thawing soft soil curing agent is prepared by the preparation method in any one of claims 1-3.

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