A soil site crack biological repair agent and a repair method

Abstract

The application discloses a kind of soil ruins crack biological repair agent and repair method, it is characterized in that, the raw material of soil ruins crack biological repair agent is carbonic anhydrase solution 21.038%, skimmed milk powder 0.07%, xanthan gum 0.018%, aspartic acid 0.018%, active magnesium oxide 5.615%, sodium bicarbonate 2.948%, straw fiber 0.105%, ruins soil powder 28.075% and fine sand 42.113% by mass percentage.The repair method is: cleaning crack; extract carbonic anhydrase solution; prepare soil ruins crack biological repair agent; fill biological repair agent.The application is based on the catalytic effect of carbonic anhydrase on carbon dioxide hydration reaction and the carbonation reaction of active magnesium oxide, forms soil ruins crack biological repair agent with good fluidity, large bonding force, high strength and low shrinkage, provides a kind of ecological compatibility stronger, more low-carbon environmental protection biological repair material and method for soil ruins.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cultural relic protection, and particularly relates to a soil site crack biological repair agent and a repair method. BACKGROUND

[0002] Soil site is an ancient site with significant historical, cultural and scientific value, which is mainly made of soil, and is an important basis for studying the origin and development of civilization. However, with the passage of time, under the influence of natural factors and human factors, the soil site appears wall root erosion and soil body cracking and other damage phenomena, which not only deteriorates the mechanical properties of the soil body and damages the structural integrity, but also provides a path for rainwater and plant roots, leading to wind erosion and further accelerating the damage of external conditions to the site body, causing more serious permanent structural damage.

[0003] At present, the reinforcing materials for soil sites in China are roughly divided into three categories: (1) inorganic materials, such as barium hydroxide solution, calcium hydroxide solution and water glass, etc.; (2) organic materials, such as organic silicon material, epoxy resin, acrylic resin, organic water-based fluorine material, etc.; (3) composite materials, such as silica sol-silicon resin material, acrylic-acrylic-silicone-epoxy resin hybrid material, etc. These materials each have certain problems and limitations to some extent, such as poor air permeability and permeability, salting out, peeling and falling off, etc.

[0004] In order to prolong the service life of the soil site, in view of the typical soil body erosion and cracking problems in the soil site, it is urgent to provide a soil site crack repair material and a repair method which have good compatibility, low shrinkage, good weather resistance and good stability. SUMMARY

[0005] In view of the poor compatibility, peeling and falling off of the soil site crack repair material in the prior art, the present application provides a soil site crack biological repair agent and a repair method.

[0006] The specific technical scheme is as follows:

[0007] A soil site crack biological repair agent, the raw materials of which are carbonic anhydrase solution 21.038%, skimmed milk powder 0.07%, xanthan gum 0.018%, aspartic acid 0.018%, active magnesium oxide 5.615%, sodium bicarbonate 2.948%, straw fiber 0.105%, site soil powder 28.075% and fine sand 42.113% by mass percentage.

[0008] The main reaction principle of the soil site crack biological repair agent is that the carbonic anhydrase catalyzes the hydration reaction of carbon dioxide and the carbonation reaction of active magnesium oxide, forming a soil site crack biological repair agent with good flowability, large adhesion, high strength and low shrinkage.

[0009] Further, the carbonic anhydrase is extracted from any one of Gracilaria lemaneiformis, thiourea hydrogen blue, and algae; the activity of the carbonic anhydrase solution is not less than 2000 kU / L.

[0010] Further, the particle sizes of the skimmed milk powder, the xanthan gum, and the aspartic acid are all less than 0.075 mm.

[0011] Further, the content of magnesium oxide in the active magnesium oxide is not less than 95%.

[0012] Further, the length of the straw fiber ranges from 10 mm to 40 mm, and the diameter ranges from 1 mm to 2 mm.

[0013] Further, the site soil powder is obtained by drying, crushing, grinding, and sieving a soil body of a repaired site soil through a 0.075 mm aperture sieve.

[0014] Further, the particle size of the fine sand ranges from 0.075 mm to 0.25 mm.

[0015] A method for repairing a crack of a site soil, which is implemented based on the biological repair agent for a crack of a site soil, and includes the following steps:

[0016] (1) A fan or a vacuum cleaner is used to clean the crack of the site soil without damaging the site soil, so as to clean the foreign matters in the crack of the site soil and avoid affecting the filling repair effect in the later period;

[0017] (2) A carbonic anhydrase solution is extracted;

[0018] (3) Skimmed milk powder, xanthan gum, aspartic acid, and sodium bicarbonate are added into the carbonic anhydrase solution to be stirred and dissolved, so as to prepare a reinforced carbonic anhydrase solution; straw fiber, active magnesium oxide, site soil powder, and fine sand are uniformly mixed to prepare a solid filling material;

[0019] (4) The reinforced carbonic anhydrase solution is added into the solid filling material to be uniformly mixed, so as to prepare the biological repair agent for a crack of a site soil; the biological repair agent for a crack of a site soil is not suitable for an extreme high-temperature environment, which may cause the carbonic anhydrase to be inactivated and affect the solidification effect;

[0020] (5) The biological repair agent for a crack of a site soil and a gas injection pipe with a gas injection hole on a side wall are filled into the crack, so that the top of the gas injection pipe is flush with the surface of the site soil; after the filling is completed, carbon dioxide gas is injected from the top of the gas injection pipe, and then the gas injection pipe is filled with the biological repair agent for a crack of a site soil, the surface is leveled, and curing is performed for more than 72 hours, so as to achieve a better solidification effect and complete the repair of the site.

[0021] Further, the step (2) is specifically: 0.3g-1g of Gracilaria lemaneiformis in the form of rope is weighed and put into a pre-cooled mortar, liquid nitrogen is added for grinding, 5mL of barbital buffer is added for mixing, and then centrifugation is performed to obtain a carbonic anhydrase solution, and the prepared carbonic anhydrase solution has an activity of not less than 2000kU / L.

[0022] Further, the soil site crack biological repair agent prepared in the step (4) is filled within 1 hour after preparation, so as to avoid the rapid solidification of the biological repair agent and affect the filling.

[0023] Further, in the step (5), the volume concentration of the injected carbon dioxide gas is 80%-100%, the injection rate is 2L / min-5L / min, and the injection time is maintained for more than 60min.

[0024] The present application has the following beneficial effects:

[0025] (1) The soil site crack biological repair agent used in the present application can quickly form a dense solidified body with high strength, low permeability, strong anti-erosion and anti-disintegration ability, good durability and the like in the soil site crack, and the solidified body and the crack side wall can be effectively cemented into a whole, so as to achieve the effect of repairing the crack.

[0026] (2) The soil site crack biological repair agent used in the present application has high solidification efficiency, can complete the repair in a short time, overcomes the problems of poor compatibility, salt precipitation, shedding, poor air permeability and permeability of traditional repair materials, and the material used is more friendly to the environment, reduces the energy consumption and carbon emission caused by raw material production, and the active magnesium oxide also has the potential of absorbing and sequestrating carbon dioxide.

[0027] (3) The soil site crack biological repair agent of the present application is convenient to construct and has strong operability when repairing the soil site crack, has a short treatment cycle and good durability, and meets the special requirements of the material for soil site repair. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 A flow chart of a soil site crack repair method provided by the present application is shown.

[0029] Figure 2 A schematic diagram of filling and gas injection treatment of soil site cracks by using the biological repair agent of the present application is shown.

[0030] Figure 3 Compressive strength test results of the biological repair materials of Examples 1-3 and Comparative Examples 1-4 of the present application are shown.

[0031] Figure 4 Flexural strength test results of the biological repair materials of Examples 1-3 and Comparative Examples 1-4 of the present application are shown.

[0032] Figure 5 Test results of water erosion resistance of the biological repair agent and the soil of Example 1 of the present application.

[0033] Figure 6 Test results of permeability coefficient of the biological repair agent and the soil of Example 1 of the present application.

[0034] Figure 7 Test results of wind erosion resistance of the biological repair agent and the soil of Example 1 of the present application for repairing the soil cracks of the site.

[0035] In the figure, the air injection hole 1, the air injection pipe 2, and the crack 3. DETAILED DESCRIPTION

[0036] The present application will be described in detail below according to the accompanying drawings and preferred embodiments, and the purposes and effects of the present application will become more apparent. The present application will be further described in detail below in combination with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0037] The present application is based on the following mechanism for repairing and strengthening the soil site: the soil site crack biological repair agent formed by mixing the carbonic anhydrase solution, the skimmed milk powder, the xanthan gum, the aspartic acid, the active magnesium oxide, the sodium bicarbonate, the straw fiber, the site soil powder, and the fine sand can quickly form a dense solidified body in the soil site crack, which has the advantages of high strength, low permeability, good ductility, strong erosion resistance and disintegration resistance, and good durability, and the dense solidified body and the crack side wall can be effectively cemented as a whole, the relative displacement of the soil site interface is controlled, and the effect of repairing the crack is achieved.

[0038] The main solidification principle of the soil site crack biological repair agent is: carbonic anhydrase catalyzes carbon dioxide hydration reaction to generate carbonate, which provides material source for carbonation of active magnesium oxide, and the carbonate reacts with the active magnesium oxide to generate hydrated magnesium carbonate cement with certain expansion, high strength, strong cementation, good stability and durability; the skimmed milk powder as the carbonic anhydrase stabilizer improves the catalytic efficiency of the carbonic anhydrase, thereby enhancing the solidification effect. The xanthan gum as the water locking agent locks the water in the soil site crack biological repair agent, avoids the secondary damage to the soil site caused by the loss of water along the soil site cracks, and the addition of the xanthan gum can increase the toughness of the cementation effect, avoid the cracks or disconnection between the surface of the soil site crack biological repair agent and the original soil site, and further improve the strength of the solidified body. The aspartic acid as the chelating agent has the effect of agglomerating the hydrated magnesium carbonate, thereby further enhancing the solidification efficiency; the straw fiber as the reinforcing material can effectively improve the deposition efficiency and yield of the hydrated magnesium carbonate, thereby further avoiding the generation of cracks and the occurrence of disconnection phenomenon, and guaranteeing the repair effect of the soil site cracks.

[0039] The application will be further illustrated by the following examples and comparative examples. It should be noted that in the following examples and comparative examples, the xanthan gum used is Fufeng brand, purchased from Shanghai National Trade Commodity City; the aspartic acid is Guo Yao Reagent brand, purchased from Ba Si Yi Laboratory Supply City; and the skimmed milk powder is Scientific Phygene brand test special type PH1519, purchased from Walidasi Experimental Reagent and Consumable Store.

[0040] Example 1

[0041] The example provides a soil site crack biological repair agent, and the raw materials are as follows in terms of mass percentage: carbonic anhydrase solution 21.038%, skimmed milk powder 0.07%, xanthan gum 0.018%, aspartic acid 0.018%, active magnesium oxide 5.615%, sodium bicarbonate 2.948%, straw fiber 0.105%, site soil powder 28.075%, and fine sand 42.113%.

[0042] The carbonic anhydrase is extracted from Gracilaria Venerabilis, the particle sizes of the skimmed milk powder, the xanthan gum and the aspartic acid are all less than 0.075 mm, and the content of the magnesium oxide in the active magnesium oxide is not less than 95%. The length of the straw fiber ranges from 10 mm to 40 mm, and the diameter ranges from 1 mm to 2 mm. The site soil powder is obtained by drying, crushing and grinding the same soil as the repaired soil site to 0.075 mm aperture sieve, and the particle size of the fine sand ranges from 0.075 mm to 0.25 mm.

[0043] The example also provides a method for repairing soil site cracks by using the soil site crack biological repair agent, which comprises the following steps:

[0044] (1) Clear the cracks of the earthen site. Use a fan or a vacuum cleaner to clean the cracks of the earthen site without damaging the earthen site, so as to clean the sundries in the cracks of the earthen site and avoid the sundries affecting the filling and repairing effect in the later stage.

[0045] (2) Extract the carbonic anhydrase solution. First, weigh 0.3-1 g of string-like Gracilaria lemaneiformis, put it into a pre-cooled mortar, add liquid nitrogen to grind thoroughly, then add 5 mL of barbital buffer to mix uniformly, and then centrifuge in a centrifuge to obtain the carbonic anhydrase solution. The activity of the carbonic anhydrase solution is not less than 2000 kU / L.

[0046] (3) Add skimmed milk powder, xanthan gum, aspartic acid and sodium bicarbonate to the carbonic anhydrase solution to stir and dissolve, to prepare a reinforced carbonic anhydrase solution; mix straw fibers, site soil powder and fine sand uniformly to prepare a solid filler.

[0047] (4) Mix the reinforced carbonic anhydrase solution with the solid filler uniformly to prepare the earthen site crack biological repair agent. The earthen site crack biological repair agent is not suitable for extremely high temperature environment, which may cause the inactivation of carbonic anhydrase and affect the solidification effect.

[0048] (5) Fill the cracks and maintain, and the specific construction process is as follows:

[0049] As shown in Figure 2 , the biological repair agent and the gas injection pipe 2 with a gas injection hole 1 in the side wall are filled into the cracks 3, so that the top of the gas injection pipe 2 is flush with the surface of the earthen site, and the inside of the gas injection pipe 2 is not filled; after filling, carbon dioxide gas is injected through the gas injection pipe 2, so that the carbon dioxide gas diffuses into the soil through the gas injection hole 1. Then the gas injection pipe 2 is filled with the biological repair agent, the surface is leveled, and the site is repaired after curing for 72 hours. The volume concentration of the injected carbon dioxide gas is 80%-100%, the injection rate is 2L / min-5L / min, and the injection time is maintained for 60 min. The curing time should be at least 72 hours to achieve better solidification effect.

[0050] It should be noted that the operation time of filling the earthen site crack biological repair agent in step (5) should not exceed 1 hour, so as to avoid the rapid solidification of the earthen site crack biological repair agent and affect the subsequent filling.

[0051] Comparative Example 1

[0052] The earthen site crack biological repair agent of the present comparative example does not add skimmed milk powder, and is identical to Example 1 in other aspects.

[0053] Comparative Example 2

[0054] The soil site crack bioremediation agent of the present comparative example does not add aspartic acid, and is otherwise identical to Example 1.

[0055] Comparative Example 3

[0056] The soil site crack bioremediation agent of the present comparative example does not add xanthan gum, and is otherwise identical to Example 1.

[0057] Comparative Example 4

[0058] The soil site crack bioremediation agent of the present comparative example does not add straw fiber, and is otherwise identical to Example 1.

[0059] Example 2

[0060] The soil site crack bioremediation agent of the present example uses site soil powder with a mass percentage of 49.132%, and fine sand with a mass percentage of 21.056%, and is otherwise identical to Example 1.

[0061] Example 3

[0062] The soil site crack bioremediation agent of the present example uses site soil powder and fine sand, both with a mass percentage of 35.094%, and is otherwise identical to Example 1.

[0063] The component contents of the bioremediation agents of Examples 1-3 are shown in Table 1 below.

[0064] Table 1

[0065]

[0066] The performance of Examples 1-3 and Comparative Examples 1-4 was evaluated as follows.

[0067] Figure 3 The compressive strength test results of the bioremediation agents prepared for Examples 1-3 and Comparative Examples 1-4 are shown below. The sample preparation method was as follows: the bioremediation agents prepared in the examples and comparative examples were filled into a cylindrical mold, placed in a sealed curing box with a carbon dioxide concentration of 90% for 72 hours, and then dried to obtain cylindrical samples with a diameter of 50 mm and a height of 100 mm. A universal testing machine was used to perform unconfined compressive strength tests, and the compressive strengths of the samples were obtained as shown in Table 2. Figure 3 The experimental results show that the sample prepared using the bioremediation agent of Example 1 has the highest compressive strength, indicating that the skimmed milk powder, xanthan gum, aspartic acid, and straw fiber in the bioremediation agent all have certain strengthening and solidifying effects, and the ratio of site soil powder to sand in the bioremediation agent of Example 1 is also better than that of Examples 2 and 3.

[0068] Figure 4The test results of the flexural strength of the bioremediation agents prepared for Examples 1-3 and Comparative Examples 1-4. The sample preparation method is as follows: the bioremediation agents prepared in the examples and comparative examples are filled into a cuboid mold, placed in a sealed curing box with a carbon dioxide concentration of 90% for 72 hours, and then dried to obtain a sample with a size of 40mm x 40mm x 160mm. The flexural strength of each sample is measured as shown in Table 1. Figure 4 As shown in Table 1, the experimental results show that the flexural strength of the sample made of the bioremediation agent of Example 1 is the highest, indicating that the skimmed milk powder, xanthan gum, aspartic acid and straw fiber in the bioremediation agent all have a certain effect of enhancing and solidifying, and the ratio of site soil powder to sand in the bioremediation agent of Example 1 is also better than that of Examples 2 and 3.

[0069] Figure 5 The test results of the water erosion resistance of the bioremediation agent prepared in Example 1 and the plain soil. The indoor erosion resistance test uses a model test, in which the rainfall simulation device uses closed-loop automatic control technology and a rotating downward spraying nozzle, the rainfall height is 2.5m, the rainfall intensity varies in the range of 100mm / h, the simulated rainfall droplet size is close to natural rainfall, the soil tank size is 0.8m x 0.6m x 0.3m, the soil tank aperture is 3mm, the hole spacing is 4cm, the front end of the soil tank support is 40cm high, and the rear end is 80cm high. The test results are shown in Table 2. Figure 5 As shown in Table 2, the experimental results show that as the rainfall time increases, the erosion amount increases with time, and during the whole rainfall erosion test, the erosion amount of the bioremediation agent prepared in the application is significantly lower than that of the plain soil, and the increase is slow, indicating that the bioremediation agent prepared in the application has good erosion resistance.

[0070] Figure 6 The test results of the permeability coefficient of the bioremediation agent prepared in Example 1 and the plain soil. The indoor permeability coefficient test is based on the "Standard for Soil Test Methods" (GB / T50123-2019), in which the triaxial sample diameter is 39.1mm and the height is 80mm. The test results are shown in Table 3. Figure 6 As shown in Table 3, the experimental results show that as the confining pressure increases, the permeability coefficient gradually decreases, and the permeability coefficient of the bioremediation agent sample prepared in the application is much smaller than that of the plain soil sample, indicating that the bioremediation agent prepared in the application can effectively reduce the water permeability of the sample.

[0071] Figure 7The results of the wind erosion resistance test of the bio-repairing agent prepared in Example 1 and the site soil for repairing the site soil cracks. The sample preparation method is as follows: two identical disc samples (10 cm in diameter and 1 cm in thickness) with cracks are prepared by using the site soil taken from Liangzhu site, one sample is repaired by using the site soil as a reference sample, and the other sample is filled and repaired by using the bio-repairing agent prepared in Example 1, and then the samples are placed in a sealed carbon dioxide maintenance box with a carbon dioxide concentration of 90% for 72 hours, and then a wind erosion test is carried out at a wind speed of 15 m / s (far more than the maximum local wind speed of the site soil) for 15 minutes, and the erosion rates of the samples are measured as shown in Table 1. Figure 7 The experimental results show that the erosion rate of the sample repaired by using the site soil is 98%, and the erosion rate of the sample treated by using the bio-repairing agent prepared in Example 1 is 0, which indicates that the bio-repairing agent prepared in the application can effectively repair the soil cracks and resist wind erosion.

[0072] Those skilled in the art can understand that the above description is only preferred examples of the application and is not used to limit the application, although the application is described in detail with reference to the foregoing examples, those skilled in the art can still modify the technical solutions recorded in the foregoing examples or make equivalent replacement for part of the technical features. Any modification, equivalent replacement, etc. within the spirit and principles of the application shall be included in the protection scope of the application.

Claims

1. A method for repairing cracks in earthen ruins, which is realized based on a crack repairing agent for earthen ruins, characterized by, The soil site crack biological repair agent comprises, in percentage by mass, carbonic anhydrase solution 21.038%, skimmed milk powder 0.07%, xanthan gum 0.018%, aspartic acid 0.018%, active magnesium oxide 5.615%, sodium bicarbonate 2.948%, straw fiber 0.105%, site soil powder 28.075%, and fine sand 42.113%; and the soil site crack repair method comprises the following steps: (1) cleaning the soil site cracks without damaging the soil site; (2) extracting a carbonic anhydrase solution; (3) adding skimmed milk powder, xanthan gum, aspartic acid, and sodium bicarbonate into the carbonic anhydrase solution to stir and dissolve, to obtain a strengthened carbonic anhydrase solution; and mixing straw fiber, active magnesium oxide, site soil powder, and fine sand to obtain a solid filling material; (4) adding the strengthened carbonic anhydrase solution into the solid filling material to mix uniformly, to obtain the soil site crack biological repair agent; (5) filling the soil site crack biological repair agent and a gas injection pipe with a gas injection hole in the side wall into the cracks, so that the top of the gas injection pipe is flush with the surface of the soil site, injecting carbon dioxide gas from the top of the gas injection pipe after the filling is completed, then filling the gas injection pipe with the soil site crack biological repair agent, leveling the surface, and curing for more than 72 hours, to complete the site repair.

2. The earthen site crack repair method of claim 1, wherein, The step (2) specifically comprises: taking 0.3g-1g of Gracilaria Venerabilis in a pre-cooled mortar, adding liquid nitrogen to grind thoroughly, then adding 5mL of barbital buffer to mix uniformly, and then centrifuging in a centrifuge to obtain the carbonic anhydrase solution.

3. The earthen site crack repair method of claim 1, wherein, The operation time for filling the soil site crack biological repair agent in the step (5) is within 1 hour after the biological repair agent prepared in the step (4) is prepared.

4. The earthen site crack repair method of claim 1, wherein, In the step (5), the volume concentration of the injected carbon dioxide gas is 80%-100%, the injection rate is 2L / min-5L / min, and the gas injection time is maintained for more than 60min.

5. The earthen site crack repair method of claim 1, wherein, The carbonic anhydrase is extracted from any one of Gracilaria Venerabilis, thiourea hydrogen blue, and algae; and the activity of the carbonic anhydrase solution is not less than 2000kU / L.

6. The earthen site crack repair method of claim 1, wherein, The particle size of the skimmed milk powder, xanthan gum, and aspartic acid is less than 0.075mm.

7. The earthen site crack repair method of claim 1, wherein, The length of the straw fiber ranges from 10mm to 40mm, and the diameter ranges from 1mm to 2mm.

8. The earthen site crack repair method of claim 1, wherein, The site soil powder is obtained by drying, crushing, grinding, and sieving through a 0.075mm aperture sieve on the same soil as the repaired soil site.

9. The method of repairing earthen site cracks of claim 1, wherein, The particle size of the fine sand ranges from 0.075mm to 0.25mm.

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