Earthen site preservation materials that inhibit expansion and reinforce them, their preparation methods and applications

Abstract

This invention discloses a bentonite archaeological site protection material that inhibits and reinforces soil structure, its preparation method, and its application. The method includes: dissolving calcium acetate in deionized water to obtain a calcium acetate solution; adding 15-crown-5 to the calcium acetate solution under stirring conditions to obtain a bentonite swelling inhibitor; preparing a POSS-DETA solution by performing a Michael addition reaction between a methacryloyl POSS cage mixture and diethylenetriamine in an organic solvent under heating; mixing the bentonite swelling inhibitor with a soil sample from the archaeological site, allowing it to stand, and then drying it to obtain modified soil; and spraying the POSS-DETA solution into the modified soil and mixing it evenly to obtain the soil archaeological site protection material. The purpose of this invention is twofold: firstly, to fundamentally inhibit the water-induced swelling activity of bentonite in the soil, reducing the damage to the archaeological site structure caused by volume changes due to wet-dry cycles; and secondly, to enhance the mechanical strength of the soil while maintaining the original water vapor migration channels of the archaeological site, avoiding secondary damage caused by closed reinforcement.

Description

Technical Field

[0001] This invention belongs to the field of earthen site protection technology, specifically relating to an earthen site protection material that inhibits expansion and reinforces it, as well as its preparation method and application. Background Technology

[0002] Earthen sites are historical remains built primarily of soil, and their structural stability is significantly affected by changes in environmental humidity. Bentonite and other clay minerals commonly found in soil exhibit the characteristic of swelling upon contact with water and shrinking upon loss of water. Under the alternating wet and dry conditions of natural climates, these clay minerals repeatedly undergo volume changes, leading to structural damage such as cracks, hollowing, and surface peeling within the site itself. This is one of the core factors threatening the long-term preservation of earthen sites. The reason for this is that montmorillonite, the main component of bentonite, exhibits significant interlayer swelling characteristics upon contact with water, resulting in the formation of interlayer Na+. + The electrostatic bonding strength between negatively charged aluminosilicate layers is relatively weak, thus requiring a large number of sodium ions to enter the interlayer region to balance the charge. When montmorillonite comes into contact with an aqueous medium, a large amount of sodium ions in the interlayer... + Hydration occurs, causing more water molecules to enter the interlayer region, resulting in a sharp increase in the spacing between montmorillonite layers and macroscopic soil expansion. When the ambient humidity decreases, the water in the interlayer is removed, causing the soil to shrink. This cycle repeats itself, exacerbating the deterioration of the site.

[0003] For structural damage such as cracks and hollow areas in earthen archaeological sites, grouting is currently the most widely used reinforcement and repair method. Existing grouting materials mostly adopt organic polymer systems or organic-inorganic composite systems. The grout is injected into the cracks of the archaeological site through grouting equipment. After solidification, it forms a filling body with a certain strength to achieve bonding and reinforcement of loose soil.

[0004] However, the aforementioned grouting materials have two significant shortcomings in practical applications. First, these materials primarily enhance soil strength through physical bonding, lacking the ability to fundamentally inhibit the expansion and contraction activity of bentonite. The repaired sections of the site will still crack again due to the continued activity of bentonite during subsequent wet-dry cycles, making it difficult to eradicate the damage. Second, organic polymer grouting materials tend to form a dense hydrophobic film on or inside the soil during the curing process. This film blocks the original moisture migration channels of the earthen site, disrupting the dynamic balance of hygroscopic and evaporative absorption between the site and the external environment. This leads to secondary problems such as increased local humidity gradients, enrichment of soluble salts, and exacerbated freeze-thaw damage, posing new safety hazards to the earthen site. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a protective material for earthen archaeological sites that inhibits expansion and strengthens the site, along with its preparation method and application. The purpose is, on the one hand, to fundamentally inhibit the water-induced swelling activity of bentonite in the soil, reducing the damage to the archaeological structure caused by volume changes due to wet-dry cycles; on the other hand, to enhance the mechanical strength of the soil while maintaining the original water vapor migration channels of the earthen archaeological site, avoiding secondary damage caused by closed reinforcement.

[0006] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution: According to a first aspect of the present invention, a method for preparing a protective material for earthen ruins that inhibits expansion and reinforces them is provided, comprising: Calcium acetate was dissolved in deionized water to obtain a calcium acetate solution. 15-crown-5 was added to the calcium acetate solution and mixed under stirring conditions to obtain a bentonite swelling inhibitor. A POSS-DETA solution was prepared by Michael addition reaction of a mixture of methacrylamide POSS cages with diethylenetriamine in an organic solvent under heating. The bentonite swelling inhibitor is mixed evenly with the soil sample of the earthen site, and then left to stand and dry to obtain modified soil. The POSS-DETA solution is sprayed into the modified soil and mixed evenly to obtain the earthen site protection material.

[0007] In one possible implementation of the first aspect, deionized water is used as the solvent, and the mass concentration of calcium acetate in the bentonite swelling inhibitor is 2 wt% to 10 wt%, and the mass concentration of 15-crown-5 is 4 wt% to 12 wt%.

[0008] In one possible implementation of the first aspect, the mass ratio of calcium acetate to 15-crown-5 in the bentonite swelling inhibitor is 1:(1~2).

[0009] In one possible implementation of the first aspect, the mass ratio of the methacryl POSS cage mixture to diethylenetriamine is (5~9):16, and the total mass concentration of the methacryl POSS cage mixture and diethylenetriamine in the organic solvent is 15 wt%~25 wt%.

[0010] In one possible implementation of the first aspect, the temperature of the Michael addition reaction is 65-75 °C.

[0011] In one possible implementation of the first aspect, the added mass of the bentonite swelling inhibitor accounts for 5 wt% to 15 wt% of the mass of the soil sample from the archaeological site.

[0012] In one possible implementation of the first aspect, the settling time during the preparation of the modified soil is 12 to 24 hours.

[0013] In one possible implementation of the first aspect, the amount of POSS-DETA solution added is 1 to 3 mL per 10 g of the modified soil.

[0014] According to a second aspect of the present invention, an earthen site protection material that inhibits expansion and reinforces it is provided, which is prepared by the method for preparing the earthen site protection material that inhibits expansion and reinforces it.

[0015] According to a third aspect of the present invention, an application is provided of the aforementioned anti-expansion and reinforcement earthen site protection material in the repair of cracks and / or hollow areas of earthen sites. The earthen site protection material is mixed evenly with water to form a slurry, which is then filled into the cracks and / or hollow areas of the earthen site and compacted.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects: This invention employs a calcium salt-crown ether synergistic system as a bentonite swelling inhibitor. This system introduces crown ether 15-crown-5, utilizing its selective complexing properties—with its annular cavity size highly matched to the diameter of sodium ions—to achieve the inhibition of interlayer Na+ in bentonite. + Precise regulation. When the inhibitor penetrates the bentonite interlayer, 15-crown-5-crown ether preferentially binds to the interlayer Na+. + A strong coordination complex is formed, resulting in a stable crown ether-Na. + Complexes effectively block Na + The hydration channels of Ca²⁺ suppress lattice expansion caused by interlayer cation hydration. Meanwhile, Ca²⁺... + As a divalent cation, its charge number is Na. + Twice the amount of Ca² required to neutralize the same lattice negative charge. + The number is significantly reduced, thus the number of cations entering the interlayer domain to participate in hydration and the number of accompanying water molecules are greatly reduced. More importantly, Ca² + The electrostatic attraction between Na and negatively charged aluminosilicate sheets is significantly stronger than that between Na and Na. + This allows for a stronger electrostatic binding effect on the aluminosilicate sheets, effectively limiting their relative displacement in humid environments and further preventing the massive embedding and interlayer expansion of water molecules. A significant synergistic effect exists between the aforementioned calcium salt and crown ether: on the one hand, 15-crown-5 complexes interlayer Na... + , for Ca² + Replacement of Na + It also creates a favorable interlayer chemical environment by exerting an electrostatic anchoring effect; on the other hand, Ca² +The introduction of [a substance] reduces the total amount of cation hydration in the interlayer domain, thus reducing the amount of Na+ required for crown ether complexation. + The quantity and the two promote each other, working together to achieve efficient and long-lasting inhibition of the swelling activity of bentonite.

[0017] Regarding the reinforcing components, this invention employs POSS-DETA as a nanoscale cross-linking reinforcing agent. The rigid cage-like framework of POSS and the flexible amine segments of DETA are covalently linked via Michael addition reaction, enabling the construction of an organic-inorganic hybrid three-dimensional network structure between soil particles. This significantly enhances the mechanical strength, adhesion, and weather resistance of the protective material. Simultaneously, POSS-DETA possesses amphiphilic molecular characteristics, preventing the formation of a dense hydrophobic film on or within the soil surface while simultaneously providing reinforcement. This maintains necessary moisture transport channels within the earthen archaeological site, ensuring a dynamic balance between moisture absorption and evaporation between the site and its external environment.

[0018] This composite protective material, through the synergistic effect of its multiple components and mechanisms, organically unifies the function of bentonite in inhibiting expansion with the function of soil structure reinforcement. It fundamentally solves the structural deterioration problem caused by the expansion and contraction of bentonite in earthen sites, while avoiding secondary protective damage caused by the excessive sealing of traditional reinforcement materials. It provides a technically feasible and reliable material solution for repairing typical defects such as warping, hollowing, and cracking in earthen sites. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the specific embodiments of the present invention, the drawings used in the description of the specific embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 This diagram illustrates the swelling inhibition principle of bentonite swelling inhibitors. Before treatment with the swelling inhibitor, when montmorillonite is soaked in water, water molecules intercalate into the montmorillonite crystal lattice and coordinate with sodium ions, causing interlayer swelling of the montmorillonite. After treatment with the swelling inhibitor, the 15-crown-5 in the inhibitor interacts with the interlayer Na... + Coordination occurs, inhibiting the hydration of sodium ions; simultaneously, the high-valence Ca... 2+ The introduction of [a substance] enhanced the electrostatic attraction of the montmorillonite layer and synergistically suppressed the interlayer expansion of montmorillonite.

[0021] Figure 2The diagram shows the comparison of the swelling height of bentonite modified with swelling inhibitors in deionized water and kerosene. From left to right, the diagram shows the bentonite without any treatment, bentonite modified with 4 wt% calcium acetate-4 wt% crown ether, 8 wt%-8 wt% crown ether, and 10 wt%-12 wt% crown ether after swelling in deionized water for 24 h.

[0022] Figure 3 The water immersion test process of the plastic cylinders obtained by pressing the bentonite inhibitor and POSS-DETA modified soil samples; in Figure (a), samples ①, ②, ③, and ④ represent the plastic cylinders obtained by pressing the untreated soil sample, the soil sample modified with 4 wt% calcium acetate-4 wt% crown ether, 8 wt%-8 wt% crown ether, and 10 wt%-12 wt% crown ether, respectively. The red arrow indicates that the structure of the plastic cylinder has completely collapsed; Figure (b) shows the optical photographs of the plastic cylinders obtained by the methods of Examples 1 to 6 after immersion in water for 30 days; Figure (c) shows the bar graph of the time required for samples ①, ②, ③, and ④ to collapse after immersion.

[0023] Figure 4 The graph shows the mass retention rate of shaped cylinders obtained by pressing soil samples modified with bentonite inhibitor and POSS-DETA during wet-dry aging cycles and freeze-thaw aging cycles. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions 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.

[0025] Example 1 A method for preparing a protective material for earthen ruins that inhibits expansion and strengthens them specifically includes the following steps: Step 1: Preparation of bentonite swelling inhibitor Calcium acetate was dissolved in deionized water and stirred until completely dissolved to obtain a calcium acetate solution. Under continuous stirring, 15-crown-5 was added to the calcium acetate solution and mixed evenly to obtain a bentonite swelling inhibitor.

[0026] In this embodiment, deionized water is used as the solvent, the mass concentration of calcium acetate in the bentonite swelling inhibitor is 4 wt%, the mass concentration of 15-crown-5 is 4 wt%, and the mass ratio of calcium acetate to 15-crown-5 is 1:1.

[0027] Step 2: Preparation of the reinforcement agent POSS-DETA solution Methacrylamide POSS cage mixture (MA-0735) and diethylenetriamine (DETA) were dissolved in ethanol, magnetically stirred thoroughly, and then heated to carry out a Michael addition reaction to obtain a POSS-DETA solution.

[0028] In this embodiment, the mass ratio of MA-0735 to DETA is 9:16, the total mass concentration of the two in ethanol is 15 wt%, and the Michael addition reaction temperature is 65 ℃.

[0029] Step 3: Preparation of protective materials for earthen ruins The bentonite swelling inhibitor obtained in step one is mixed and stirred evenly with the soil sample of the earthen site. After standing, it is placed in a forced-air drying oven to dry, thus obtaining modified soil modified with bentonite swelling inhibitor. Then, the POSS-DETA solution obtained in step two is sprayed into the modified soil and mixed evenly to obtain mud-like earthen site protection material.

[0030] In this embodiment, the amount of bentonite swelling inhibitor added accounts for 5 wt% of the mass of the soil sample from the earthen site; after being mixed evenly with the soil sample, it is allowed to stand for 12 hours to complete the modification; when adding POSS-DETA solution to the modified soil, 1 mL of POSS-DETA solution is added for every 10 g of modified soil, and after stirring evenly, it is dried in a forced-air oven to obtain the modified and reinforced soil sample (i.e., earthen site protection material).

[0031] The on-site application method is as follows: When using it, spray an appropriate amount of water onto the modified and reinforced soil sample and mix it evenly to obtain a mud-like protective material. Then fill the cracks and / or hollow areas of the earthen site with the protective material and compact it to achieve reinforcement and protection.

[0032] To evaluate the protection effect of this embodiment, the following experiment was designed.

[0033] 5 wt% bentonite was added to untreated soil to simulate a bentonite-containing soil sample from an archaeological site. The bentonite-doped simulated soil sample was modified and reinforced using the method described in this embodiment to obtain a protective material for the archaeological site, and its performance was then tested. First, a soil sample was shaped into a cylindrical form by applying a pressure of 5 MPa to 4.3 g of the protective material using a mold and a tablet press, simulating the protective layer formed after compaction during on-site application. Subsequently, the shaped soil sample was subjected to tap water immersion tests, wet heat aging cycle tests, and freeze-thaw aging cycle tests to comprehensively evaluate the water resistance and weather resistance of the protective material.

[0034] In the tap water immersion experiment, soil sample cylinders protected by different materials were simultaneously immersed in a water tank, and the time for complete soil collapse was recorded. The specific procedure for the wet-heat aging cycle was as follows: the soil sample cylinders were immersed in tap water for 2 hours, then dried in a 60℃ oven for 2 hours, and this cycle was repeated multiple times, recording the mass of the soil sample cylinders after each drying. The specific procedure for the freeze-thaw aging cycle was as follows: the soil sample cylinders were immersed in tap water for 2 hours, then frozen in a -20℃ freezer for 4 hours, and this cycle was repeated multiple times, recording the mass of the soil sample cylinders after each immersion.

[0035] Experimental results Figure 1 This is a schematic diagram illustrating the mechanism of action of the bentonite swelling inhibitor described in this invention, detailing the principle of synergistic inhibition of interlayer swelling by calcium salts and crown ethers. The left figure shows the destructive mechanism of bentonite on earthen sites under wet-dry cycles: water molecules insert into the interlayer due to the hydrophilicity of bentonite, causing swelling; sodium ion hydration further exacerbates this process; when the temperature rises or the humidity decreases, the water in the interlayer is removed, leading to shrinkage; this cycle repeats, causing the site to deteriorate. The right figure shows that after modification with the inhibitor, 15-crown-5 is pre-intercalated and coordinates interlayer sodium ions through the annular cavity, weakening its hydration capacity; simultaneously, the introduction of calcium ions enhances the electrostatic attraction with the layers, synergistically inhibiting interlayer swelling.

[0036] Figure 3 (a) shows the water immersion process of a molded cylinder obtained by pressing a modified soil sample without POSS-DETA reinforcement and a molded cylinder obtained by pressing a modified soil sample with POSS-DETA reinforcement. Figure 3 (c) shows the time it took for different soil samples to collapse after being soaked in water. Figure 3 In (a) of the diagram, ①, ②, ③, and ④ represent shaped cylinders formed from untreated soil samples, soil samples modified with 4 wt% calcium acetate-4 wt% crown ether, 8 wt% calcium acetate-8 wt% crown ether, and 10 wt% calcium acetate-12 wt% crown ether, respectively (none of which had POSS-DETA added). Figure 3 As shown in (a), the addition of the bentonite swelling inhibitor significantly enhanced the water resistance of the molded cylinders. Molded cylinders made from unmodified soil collapsed after immersion in water for 60 seconds; while molded cylinders made from soil modified with 4 wt% calcium acetate-4 wt% crown ether, 8 wt% calcium acetate-8 wt% crown ether, and 10 wt% calcium acetate-12 wt% crown ether showed extended collapse times of 120 seconds, 480 seconds, and 300 seconds respectively, representing increases of 100%, 700%, and 400% compared to the unmodified samples. This indicates that the bentonite swelling inhibitor described in this invention can significantly improve the problem of water-induced swelling and deterioration of soil structures. Figure 3(b) is an optical photograph of the shaped cylinders obtained in Examples 1-6 after being immersed in water for more than 30 days. The image shows that all the shaped cylinders maintained structural stability during the immersion process without any changes in morphology or loss of mass, which proves the structural enhancement effect of POSS-DETA on the earthen site samples.

[0037] Figure 4 This demonstrates the mass loss of the shaped cylinder prepared by pressing the protective material obtained in this embodiment during wet-dry aging cycles and freeze-thaw aging cycles. Tests were conducted, combined with... Figure 4 As shown in (a) and (b), the shaped cylinder maintained a mass retention rate of over 97.90% after 30 wet-dry aging cycles and over 99.24% after 30 freeze-thaw aging cycles, indicating that the protective material prepared in this embodiment can be used as a long-lasting grouting protection material for earthen sites. Furthermore, after soaking in tap water for 24 hours, the mass of the shaped cylinder before and after soaking was tested, and the water absorption rate was measured to be 7.8%, indicating that the earthen site protection material obtained in this embodiment still possesses air permeability and water absorption, which is beneficial for preserving the original water vapor transport channels of the earthen site and avoiding protective damage.

[0038] Example 2 A method for preparing a protective material for earthen ruins that inhibits expansion and strengthens them specifically includes the following steps: Step 1: Preparation of bentonite swelling inhibitor Calcium acetate was dissolved in deionized water and stirred until completely dissolved to obtain a calcium acetate solution. Under continuous stirring, 15-crown-5 was added to the calcium acetate solution and mixed evenly to obtain a bentonite swelling inhibitor.

[0039] In this embodiment, deionized water is used as the solvent, the mass concentration of calcium acetate in the bentonite swelling inhibitor is 8 wt%, the mass concentration of 15-crown-5 is 8 wt%, and the mass ratio of calcium acetate to 15-crown-5 is 1:1.

[0040] Step 2: Preparation of the reinforcement agent POSS-DETA solution Methacrylamide POSS cage mixture (MA-0735) and diethylenetriamine (DETA) were dissolved in ethanol, magnetically stirred thoroughly, and then heated to carry out a Michael addition reaction to obtain a POSS-DETA solution.

[0041] In this embodiment, the mass ratio of MA-0735 to DETA is 9:16, the total mass concentration of the two in ethanol is 20 wt%, and the Michael addition reaction temperature is 70 ℃.

[0042] Step 3: Preparation of protective materials for earthen ruins The bentonite swelling inhibitor obtained in step one is mixed and stirred evenly with the soil sample of the earthen site. After standing, it is dried in a forced-air drying oven to obtain modified soil. Then, the POSS-DETA solution obtained in step two is sprayed into the modified soil and mixed evenly to obtain mud-like earthen site protection material.

[0043] In this embodiment, the amount of bentonite swelling inhibitor added accounts for 10 wt% of the mass of the soil sample from the archaeological site; after being mixed evenly with the soil sample, it is allowed to stand for 24 hours to complete the modification; when adding POSS-DETA solution to the modified soil, 3 mL of POSS-DETA solution is added for every 10 g of modified soil, and after stirring evenly, it is dried in a forced-air oven to obtain the modified and reinforced soil sample.

[0044] The on-site application method is the same as in Example 1.

[0045] Soil samples were shaped into cylinders using the method described in Example 1 and evaluated under the same testing conditions.

[0046] Experimental results Figure 4 This demonstrates the mass loss of the shaped cylinder prepared by pressing the protective material obtained in this embodiment during wet-dry aging cycles and freeze-thaw aging cycles. Tests were conducted, combined with... Figure 4 As shown in (a) and (b), the shaped cylinder maintained a mass retention rate of over 98.29% after 30 wet-dry aging cycles and over 99.59% after 30 freeze-thaw aging cycles, indicating that the protective material prepared in this embodiment can be used as a long-lasting grouting protection material for earthen sites. Furthermore, after soaking in tap water for 24 hours, the mass of the shaped cylinder before and after soaking was tested, and the water absorption rate was measured to be 8.9%, indicating that the material has good air permeability and water absorption, which is beneficial for preserving the original water vapor transport channels of earthen sites and avoiding protective damage.

[0047] Example 3 A method for preparing a protective material for earthen ruins that inhibits expansion and strengthens them specifically includes the following steps: Step 1: Preparation of bentonite swelling inhibitor The process is the same as step one in Example 2, that is, the mass concentration of calcium acetate in the bentonite swelling inhibitor is 8 wt%, the mass concentration of 15-crown-5 is 8 wt%, and the mass ratio of the two is 1:1.

[0048] Step 2: Preparation of the reinforcement agent POSS-DETA solution The reaction was carried out in the same manner as step two of Example 2, namely, the mass ratio of MA-0735 to DETA was 9:16, the total mass concentration in ethanol was 20 wt%, and the reaction temperature was 70 ℃.

[0049] Step 3: Preparation of protective materials for earthen ruins The bentonite swelling inhibitor obtained in step one is mixed and stirred evenly with the soil sample of the earthen site, allowed to stand, and then dried to obtain modified soil; then the POSS-DETA solution obtained in step two is sprayed into the modified soil and mixed evenly to obtain mud-like earthen site protection material.

[0050] In this embodiment, the amount of bentonite swelling inhibitor added was 10 wt% of the soil sample mass; the standing time was 24 hours; and the amount of POSS-DETA solution added was 2 mL per 10 g of modified soil.

[0051] The on-site application method is the same as in Example 1.

[0052] Soil samples were shaped into cylinders and tested following the method described in Example 1.

[0053] Experimental results Figure 4 This paper demonstrates the wet-dry aging cycle and freeze-thaw aging cycle of the shaped cylinder prepared by pressing the protective material obtained in this embodiment, and illustrates the mass loss process during these cycles. Tests showed that the shaped cylinder retained a mass retention rate of over 98.60% after 30 wet-dry aging cycles and over 99.24% after 30 freeze-thaw aging cycles, indicating that the protective material prepared in this embodiment can serve as a long-lasting grouting protection material for earthen sites. Furthermore, after soaking in tap water for 24 hours, the mass of the shaped cylinder before and after soaking was tested, revealing a 9.3% increase in mass. This indicates that the earthen site protection material obtained in this embodiment still possesses air permeability and water absorption, which is beneficial for preserving the original moisture transport channels of the earthen site and preventing protective damage.

[0054] Example 4 A method for preparing a protective material for earthen ruins that inhibits expansion and strengthens them specifically includes the following steps: Step 1: Preparation of bentonite swelling inhibitor The process is the same as step one in Example 2, that is, the mass concentration of calcium acetate in the bentonite swelling inhibitor is 8 wt%, the mass concentration of 15-crown-5 is 8 wt%, and the mass ratio of the two is 1:1.

[0055] Step 2: Preparation of the reinforcement agent POSS-DETA solution The reaction was carried out in the same manner as step two of Example 2, namely, the mass ratio of MA-0735 to DETA was 9:16, the total mass concentration in ethanol was 20 wt%, and the reaction temperature was 70°C.

[0056] Step 3: Preparation of protective materials for earthen ruins The bentonite swelling inhibitor obtained in step one is mixed and stirred evenly with the soil sample of the earthen site, allowed to stand, and then dried to obtain modified soil; then the POSS-DETA solution obtained in step two is sprayed into the modified soil and mixed evenly to obtain the earthen site protection material.

[0057] In this embodiment, the amount of bentonite swelling inhibitor added was 10 wt% of the soil sample mass; the standing time was 24 hours; and the amount of POSS-DETA solution added was 1 mL per 10 g of modified soil.

[0058] The on-site application method is the same as in Example 1.

[0059] Soil samples were shaped into cylinders and tested following the method described in Example 1.

[0060] Experimental results Figure 4 This paper demonstrates the dry-wet aging cycle and freeze-thaw aging cycle processes of the shaped cylinder prepared by pressing the protective material obtained in this embodiment, as well as the mass loss process. Tests showed that the shaped cylinder retained a mass retention rate of over 98.06% after 30 dry-wet aging cycles and over 97.63% after 30 freeze-thaw aging cycles, indicating that the protective material prepared in this embodiment can be used as an effective grouting protection material for earthen sites. Furthermore, after soaking in tap water for 24 hours, the mass of the shaped cylinder before and after soaking was tested, and a water absorption rate of 8.8% was measured. This indicates that the earthen site protection material obtained in this embodiment still possesses air permeability and water absorption, which is beneficial for preserving the original water vapor transport channels of the earthen site and preventing protective damage.

[0061] Example 5 A method for preparing a protective material for earthen ruins that inhibits expansion and strengthens them specifically includes the following steps: Step 1: Preparation of bentonite swelling inhibitor Calcium acetate was dissolved in deionized water and stirred until completely dissolved to obtain a calcium acetate solution. Under continuous stirring, 15-crown-5 was added to the calcium acetate solution and mixed evenly to obtain a bentonite swelling inhibitor.

[0062] In this embodiment, deionized water is used as the solvent, the mass concentration of calcium acetate in the bentonite swelling inhibitor is 2 wt%, the mass concentration of 15-crown-5 is 4 wt%, and the mass ratio of calcium acetate to 15-crown-5 is 1:2.

[0063] Step 2: Preparation of the reinforcement agent POSS-DETA solution Methacrylamide POSS cage mixture (MA-0735) and diethylenetriamine (DETA) were dissolved in ethanol, magnetically stirred thoroughly, and then heated to carry out a Michael addition reaction to obtain a POSS-DETA solution.

[0064] In this embodiment, the mass ratio of MA-0735 to DETA is 7:16, the total mass concentration of the two in ethanol is 25 wt%, and the Michael addition reaction temperature is 68 ℃.

[0065] Step 3: Preparation of protective materials for earthen ruins The bentonite swelling inhibitor obtained in step one is mixed and stirred evenly with the soil sample of the earthen site. After standing, it is dried in a forced-air drying oven to obtain modified soil. Then, the POSS-DETA solution obtained in step two is sprayed into the modified soil and mixed evenly to obtain mud-like earthen site protection material.

[0066] In this embodiment, the amount of bentonite swelling inhibitor added accounts for 15 wt% of the mass of the soil sample from the archaeological site; after being mixed evenly with the soil sample, it is allowed to stand for 24 hours to complete the modification; when adding POSS-DETA solution to the modified soil, 2 mL of POSS-DETA solution is added for every 10 g of modified soil, and after stirring evenly, it is dried in a forced-air oven to obtain the modified and reinforced soil sample.

[0067] The on-site application method is the same as in Example 1.

[0068] Soil samples were shaped into cylinders and tested following the method described in Example 1.

[0069] Experimental results Figure 4 This demonstration shows the mass loss of the molded cylinder prepared by pressing the protective material obtained in this embodiment during wet-dry aging cycles and freeze-thaw aging cycles. After 30 wet-dry aging cycles, the mass retention rate remained above 98.06%, and after 30 freeze-thaw aging cycles, the mass retention rate remained above 97.63%. After soaking in tap water for 24 hours, the mass of the molded cylinder before and after soaking was tested, and the water absorption rate was measured to be 8.1%.

[0070] Example 6 A method for preparing a protective material for earthen ruins that inhibits expansion and strengthens them specifically includes the following steps: Step 1: Preparation of bentonite swelling inhibitor Calcium acetate was dissolved in deionized water and stirred until completely dissolved to obtain a calcium acetate solution. Under continuous stirring, 15-crown-5 was added to the calcium acetate solution and mixed evenly to obtain a bentonite swelling inhibitor.

[0071] In this embodiment, deionized water is used as the solvent, the mass concentration of calcium acetate in the bentonite swelling inhibitor is 10 wt%, the mass concentration of 15-crown-5 is 12 wt%, and the mass ratio of calcium acetate to 15-crown-5 is 1:1.2.

[0072] Step 2: Preparation of the reinforcement agent POSS-DETA solution Methacrylamide POSS cage mixture (MA-0735) and diethylenetriamine (DETA) were dissolved in ethanol, magnetically stirred thoroughly, and then heated to carry out a Michael addition reaction to obtain a POSS-DETA solution.

[0073] In this embodiment, the mass ratio of MA-0735 to DETA is 5:16, the total mass concentration of the two in ethanol is 15 wt%, and the Michael addition reaction temperature is 75 ℃.

[0074] Step 3: Preparation of protective materials for earthen ruins The bentonite swelling inhibitor obtained in step one is mixed and stirred evenly with the soil sample of the earthen site. After standing, it is dried in a forced-air drying oven to obtain modified soil. Then, the POSS-DETA solution obtained in step two is sprayed into the modified soil and mixed evenly to obtain mud-like earthen site protection material.

[0075] In this embodiment, the amount of bentonite swelling inhibitor added accounts for 9 wt% of the mass of the soil sample from the archaeological site; after being mixed evenly with the soil sample, it is allowed to stand for 18 hours to complete the modification; when adding POSS-DETA solution to the modified soil, 1.5 mL of POSS-DETA solution is added for every 10 g of modified soil, and after stirring evenly, it is dried in a forced-air oven to obtain the modified and reinforced soil sample.

[0076] The on-site application method is the same as in Example 1.

[0077] To verify the individual inhibitory effect of the bentonite swelling inhibitor described in this invention on the swelling behavior of bentonite, different concentrations of bentonite swelling inhibitor were prepared according to the method in step one of the embodiments, and then used to modify pure bentonite. Specifically, equal masses of untreated bentonite and modified bentonite were soaked in deionized water or kerosene for 24 hours, respectively; then centrifuged at 4000 rad / min, the final swelling height of the bentonite was measured, and the swelling inhibition rate B was calculated according to the following formula:

[0078] In the formula: The swelling height of untreated bentonite in deionized water; The swelling height of untreated bentonite in kerosene; This refers to the swelling height of modified bentonite in deionized water.

[0079] Measurements showed that the swelling height of untreated bentonite in kerosene was 1.20 cm. The swelling heights of untreated bentonite, bentonite modified with 4 wt% calcium acetate-4 wt% crown ether, 8 wt% calcium acetate-8 wt% crown ether, and 10 wt% calcium acetate-12 wt% crown ether in deionized water were 1.90 cm, 1.40 cm, 1.36 cm, and 1.32 cm, respectively. See also... Figure 2 The swelling inhibition rates of the modified soil samples were calculated to be 71.43%, 77.14%, and 82.86%, respectively. The results indicate that the bentonite swelling inhibitor described in this invention can effectively inhibit interlayer swelling of bentonite in an aqueous environment.

[0080] Finally, it should be noted that the above-described embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit them. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the scope of the technology disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a protective material for earthen ruins that inhibits expansion and strengthens them, characterized in that, include: Calcium acetate was dissolved in deionized water to obtain a calcium acetate solution. 15-crown-5 was added to the calcium acetate solution and mixed under stirring conditions to obtain a bentonite swelling inhibitor. A POSS-DETA solution was prepared by Michael addition reaction of a mixture of methacrylamide POSS cages with diethylenetriamine in an organic solvent under heating. The bentonite swelling inhibitor is mixed evenly with the soil sample of the earthen site, and then left to stand and dry to obtain modified soil. The POSS-DETA solution is sprayed into the modified soil and mixed evenly to obtain the earthen site protection material.

2. The method for preparing an earthen archaeological site protection material that inhibits expansion and reinforces it according to claim 1, characterized in that, Using deionized water as a solvent, the mass concentration of calcium acetate in the bentonite swelling inhibitor is 2 wt%~10 wt%, and the mass concentration of 15-crown-5 is 4 wt%~12 wt%.

3. A method for preparing an earthen archaeological site protection material that inhibits expansion and reinforces it according to claim 2, characterized in that, In the bentonite swelling inhibitor, the mass ratio of calcium acetate to 15-crown-5 is 1:(1~2).

4. A method for preparing an earthen archaeological site protection material that inhibits expansion and reinforces it according to claim 1, characterized in that, The mass ratio of the methacryl POSS cage mixture to diethylenetriamine is (5~9):16, and the total mass concentration of the methacryl POSS cage mixture and diethylenetriamine in the organic solvent is 15 wt%~25 wt%.

5. A method for preparing an earthen archaeological site protection material that inhibits expansion and reinforces it according to claim 1, characterized in that, The Michael addition reaction is carried out at a temperature of 65-75 °C.

6. A method for preparing an earthen archaeological site protection material that inhibits expansion and reinforces it according to claim 1, characterized in that, The added bentonite swelling inhibitor accounts for 5 wt% to 15 wt% of the soil sample mass of the archaeological site.

7. The method for preparing an earthen archaeological site protection material that inhibits expansion and reinforces it according to claim 1, characterized in that, During the preparation of the modified soil, the settling time is 12-24 hours.

8. A method for preparing an earthen archaeological site protection material that inhibits expansion and reinforces it according to claim 1, characterized in that, The amount of POSS-DETA solution added is 1~3 mL per 10 g of the modified soil.

9. A protective material for earthen ruins that inhibits expansion and reinforces them, characterized in that, The material is prepared by any one of claims 1 to 8 as a method for preparing an earthen site protection material that inhibits expansion and reinforces it.

10. The application of a protective material for earthen sites that inhibits expansion and reinforces it as described in claim 9 in the repair of cracks and / or hollow areas in earthen sites, characterized in that, Mix the earthen site protection material with water to form a slurry, fill the cracks and / or hollow areas of the earthen site, and then compact it.

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