Method for repairing earthen ruins by using biological slurry

Abstract

The invention discloses a method for biologically repairing an earthen ruins, which comprises the following steps: 1) selecting a soil body consistent with the earthen ruins, and stirring the soil body with biological slurry in proportion to prepare a repairing filler; (2) selecting the bamboo canes which are soaked in saline water and cooked at high temperature to construct a supporting framework in a to-be-repaired area in a layered manner, and filling a repairing filler; and 3) spraying the biological treatment liquid on the repaired area and the peripheral surface thereof for multiple times and maintaining. According to the principle of'repairing old as old 'in cultural relic repairing, the earthen ruins are repaired and reinforced by utilizing the biological slurry based on the biological curing technology, the repairing efficiency is high, and the repairing effect is good. Meanwhile, when the earthen ruins are repaired through the technology researched and developed by the method, no obvious repairing traces exist in the repairing area, and the original historical deposits and styles of the earthen ruins can be well shown.

Description

Technical Field

[0001] The invention relates to the field of earthen ruins restoration, and in particular to a method for repairing earthen ruins using biological mud. Background Art

[0002] Earthen sites are the architectural heritage and historical and cultural heritage of ancient Chinese dwellings. They are the crystallization of the wisdom of the ancient working people and have a strong historical background and artistic value. Under the long-term influence of the environment and human factors in history, the mechanical properties of the materials used in the construction of earthen sites will inevitably deteriorate to varying degrees, and in the long history, earthen sites will inevitably be damaged by various natural and human factors, causing earthen sites to crack to varying degrees and even collapse. In order to inherit the historical memory of human civilization, effective protection of earthen sites and repair of damaged earthen sites based on the principle of "repairing the old as the old" have great historical value, scientific value and artistic value. However, limited by the existing level of earthen site restoration technology, cultural relics protection units at this stage have to violate the principle of "repairing the old as the old" in the repair of ancient buildings, and use concrete and steel supports to reinforce and repair earthen sites. Obviously, this method is difficult to show the original historical background and style of earthen sites. In view of this, the present invention will follow the principle of "repairing the old as the old, not changing the original state of cultural relics" in cultural relics protection, and propose a method for repairing earthen sites using biological mud. Summary of the invention

[0003] In order to solve the problems existing in the restoration process of earthen sites, the present invention proposes a method for repairing earthen sites using biological mud. This method has high efficiency and good effect in repairing earthen sites. The repaired earthen sites have strong anti-erosion ability and no obvious signs of repair. It strictly abides by the principle of cultural relics protection of "repairing the old as it is and not changing the original state of cultural relics".

[0004] The present invention is achieved through the following technical solutions: A method for repairing earthen ruins using bio-mud comprises the following steps: (1) Mixing the urease-producing bacteria liquid and the cementing liquid, stirring them continuously, letting them stand, and removing the supernatant to obtain the bioslurry; (2) Mix the bio-mud, the cementing liquid and the soil of the site to be repaired and stir them evenly to prepare the repair filler; (3) Select bamboo strips that have been soaked in salt water and steamed at high temperature to construct a support frame in layers in the area to be repaired and fill it with repair fillers. Use the remaining repair fillers to fill the gaps at the edges; (4) Mix the bean enzyme solution and the binder solution to prepare the biological treatment solution, and spray the biological treatment solution on the repair area and its surrounding surfaces several times for maintenance.

[0005] Furthermore, the binder liquid is a mixed liquid containing urea and CaCl2 in equimolar concentrations.

[0006] Furthermore, the volume ratio of the urease-producing bacteria liquid and the binder liquid in step (1) is 3:1-7:1, the concentration of the binder liquid is 4.0 mol / L, the stirring time is 8-12 h, and the standing time is 4-6 h.

[0007] Furthermore, in step (2), the mass ratio of the binder, the bio-mud, and the soil of the earthen ruins to be repaired is 1:1:8~3:1:16; the concentration of the binder is 2.0~4.0 mol / L, and the moisture content of the repair filler is 25~30%.

[0008] Furthermore, the bamboo strips described in step (3) are freshly cut bamboo strips that are first soaked in salt water with a concentration of 5% to 10% for 1 to 2 days, dried in the shade, and then boiled in boiling water at 100° C. for 6 to 12 hours.

[0009] Furthermore, the degree of compaction of the repair filler filling the area to be repaired is not less than 90%.

[0010] Furthermore, in step (4), the soybean enzyme solution and the binder solution are mixed in a volume ratio of 1:1, and the concentration of the binder solution is 2.0 mol / L.

[0011] Furthermore, the soybean enzyme solution in step (4) is prepared by stirring raw soybean powder and water for 30 minutes, standing at 4°C for 12-24 hours, and separating the upper suspension to obtain the soybean enzyme solution, and the amount of raw soybean powder used is 80-100 g / L.

[0012] Furthermore, the spraying volume of the biological treatment liquid in step (4) is 2-2.5 L / m 2 / Second-rate.

[0013] Furthermore, in step (4), the biological treatment liquid is sprayed 3 to 7 times, and the time interval between each spraying is 24 hours.

[0014] As a preferred method, the bamboo strips used should be processed from newly cut local bamboo.

[0015] The principle of the present invention is to use urease-producing bacteria liquid and cementing liquid to prepare biological mud with high concentration of urease-producing bacteria. The urease-producing bacteria contained in the biological mud will hydrolyze urea in the cementing liquid and induce the formation of calcium carbonate crystals with cementing effect. At the same time, since the urease-producing bacteria are separated from the soil, they can survive and reproduce in the soil for a long time, so that the repair area can be repeatedly sprayed and solidified. By spraying biological treatment liquid (using soybean urease and cementing liquid), the filled repair area is repeatedly reinforced to improve its durability and erosion resistance.

[0016] The beneficial effects of the present invention are: introducing biological mud with high concentration of urease-producing bacteria into the soil by premixing, increasing the content of urease-producing bacteria per unit volume of the soil, and having higher biomineralization efficiency and in-situ treatment and reinforcement capabilities. In addition, the area repaired by the method described in the present invention has no obvious signs of repair, strictly abides by the principle of "repairing the old as it is" in cultural relics restoration, and better shows the original style of the earthen site. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a flow chart for repairing the present invention.

[0018] Figure 2 Prepare a flow chart for repairing the packing.

[0019] Figure 3 Fill compaction diagram for repair area.

[0020] Figure 4 Prepare a flow chart for the biological treatment fluid.

[0021] Figure 5 This is the effect of the sample surface being sprayed with biological treatment liquid for reinforcement treatment.

[0022] Figure 6 The disintegration rate diagram of Examples 1, 2, 3 and Comparative Examples 1, 2 after being immersed in water for 24 hours.

[0023] Figure 7 The results of the 24-hour corrosion resistance test of Example 1 in water are shown in FIG.

[0024] Figure 8 The direct shear test results of Example 1 are shown in FIG.

[0025] Fig. 9 The direct shear test results of Example 2 are shown in FIG.

[0026] Fig.10 The direct shear test results of Example 3 are shown in FIG.

[0027] Fig.11 The direct shear test results of comparative example 2 are shown in FIG. DETAILED DESCRIPTION

[0028] In order to make the contents of the present invention easier to understand, the technical solutions of the present invention are further described below in conjunction with specific implementation methods.

[0029] The urease-producing bacterial liquid used in this embodiment is the pasteurian spore octahedral liquid. The pasteurian spore octahedral strain is isolated and extracted from the soil and the mother bacteria are obtained by purification and screening through the conventional plate streak method. The obtained strain is inoculated into the YE-NH4 liquid culture medium for expansion culture. The components of the culture medium include: 20 g / L yeast, 15 g / L ammonium chloride (NH4Cl), and 0.025 mM nickel chloride (NiCl2). The mother bacteria are inoculated into a conical flask at a volume ratio of 1:1000, and it is placed in a constant temperature shaker. It is cultured at 30 ° C and 150 rpm for 20 hours to obtain a urease-producing bacterial liquid.

[0030] The soil used in this embodiment comes from the fully weathered and strongly weathered granite residual soil near the surface of Xiyuan Palace area in Fuzhou.

[0031] Example 1 1. Preparation of repair filler and treatment of the area to be repaired 1) Dissolve 240 g of urea and 444 g of anhydrous calcium chloride in water and adjust the volume to 1L to obtain a 4 mol / L cementing solution; mix the urease-producing bacterial solution with the 4 mol / L cementing solution at a volume ratio of 4:1, and stir at 600 rpm for 12 hours. After stirring, place the mixture in a refrigerator at 4°C and let it stand for 6 hours. After standing, remove the supernatant to obtain biological mud, such as Figure 2 shown.

[0032] 2) The bioslurry, 4 mol / L concentration binder and soil completely dried at 105 °C were mixed in a mass ratio of 1:1:8 and stirred evenly to obtain a repair filler. The moisture content of the repair filler was 25%.

[0033] 3) Soak the newly cut bamboo strips in 10% salt water for 2 days, dry them in the shade, and then boil them in 100°C boiling water for 12 hours. The resulting bamboo strips are used as the supporting skeleton.

[0034] 4) Construct the support frame in layers in the area to be repaired and fill it with repair fillers, such as Figure 3 As shown, the dimensions of the specimen are 61.8 mm in diameter and 40 mm in height.

[0035] 5) Use the remaining repair filler to fill the gaps at the edges to ensure that there are no cracks in the area to be repaired.

[0036] 2. Preparation of biological treatment fluid and spraying of the area to be repaired 1) Mix raw soybean powder and tap water in a mass ratio of 1:10, with the amount of raw soybean powder being 100g / L, and stir for 30 minutes. Place the stirred mixed solution in a refrigerator at 4°C and let it stand for 12 hours. The upper suspension separated after standing is the soybean enzyme solution.

[0037] 2) If Figure 4 As shown in the figure, the bean enzyme solution and 2 mol / L cementing liquid were mixed in a volume ratio of 1:1 to prepare the biological treatment solution, which was evenly sprayed on the repaired area after filling. The single spraying volume was 2 L / m 2 , a total of 7 sprayings, each spraying interval is 24 hours. Figure 5 shown.

[0038] 3) Conduct indoor disintegration test on the treated soil samples, and place the soil samples in water for 1 minute, 5 minutes, 10 minutes, 30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, 12 hours and 24 hours. The test results are as follows: Figure 6 , 7 As shown in the figure, the sample can still maintain its original shape after being immersed in water for 24 hours, and the disintegration rate of the sample is A t is 0%. The formula for calculating the disintegration rate is A t =(R0-R t ) / R0, where R 0 is the initial mass of the sample, R t is the mass of the sample at time t. The test results show that the soil treated by mixing and spraying has good anti-collapse performance.

[0039] At the same time, direct shear tests were carried out on the samples. The test set 4 groups of different normal stresses, namely 100 kPa, 200 kPa, 300 kPa, and 400 kPa, with a shear rate of 0.8 mm / min and a shear amount of 6 mm. According to the "Geotechnical Test Method Standard GB / T50123-2019", under each group of normal stress, the shear stress corresponding to the shear amount of 4 mm is taken as the corresponding shear strength under the normal stress. The obtained shear strength values ​​are plotted on a graph and linearly fitted. The slope and intercept of the straight line are the internal friction angle and cohesion. The test results are as follows: Figure 8 As shown in the figure, the strength of the soil treated by the method proposed in the present invention is effectively improved. The cohesion of the sample can reach 62.65 kPa, and the internal friction angle is 27.03°.

[0040] Example 2 The same processing technology as in Example 1 is used to prepare the repair filler, and a layered support skeleton is constructed and the repair filler is filled.

[0041] The biological treatment solution was prepared by mixing soybean enzyme solution and 2 mol / L cementing solution in a volume ratio of 1:1. The solution was evenly sprayed on the repaired area after filling. The single spraying volume was 2 L / m 2 , spray 3 times in total, and the interval between each spraying is 24 hours.

[0042] The treated samples were subjected to disintegration test and direct shear test. Figure 6 As shown in Figure 2, the sample exhibited good anti-disintegration performance. The disintegration rate of the sample was only 10% after being immersed in water for 24 h. The direct shear test results are shown in Figure 2. Fig. 9 As shown in the figure, the cohesion of the sample is 54.7 kPa and the internal friction angle is 25.65°.

[0043] Example 3 The same processing technology as in Example 1 is used to prepare the repair filler, and a layered support skeleton is constructed and the repair filler is filled.

[0044] The biological treatment solution was prepared by mixing soybean enzyme solution and 2 mol / L cementing solution in a volume ratio of 1:1. The solution was evenly sprayed on the repaired area after filling. The single spraying volume was 2 L / m 2 , spray 5 times in total, and the interval between each spraying is 24 hours.

[0045] The treated samples were subjected to disintegration test and direct shear test. Figure 6 As shown in Figure 2, the sample exhibited good anti-disintegration performance. The disintegration rate of the sample was only 7.4% after being immersed in water for 24 h. The direct shear test results are shown in Figure 2. Fig.10 As shown in the figure, the cohesion of the sample is 61.4 kPa and the internal friction angle is 24.71°.

[0046] Comparative Example 1 A control test was conducted on the soil without any treatment. The specific sample preparation steps are as follows: 1) Mix completely dried soil with water in a mass ratio of 4:1. The moisture content of the soil after mixing is 25%; 2) Load the mixed soil into the ring knife sample maker and compact it. The compaction degree of the sample is 95%.

[0047] Disintegration test results Figure 6 As shown in the figure, the disintegration rate of the sample reached 100% (complete disintegration) within 10 min.

[0048] Comparative Example 2 The same treatment process as in Example 1 was used to prepare the repair filler, and a layered support frame was constructed and the repair filler was filled in. No bean enzyme solution was used for spraying reinforcement as a control test.

[0049] Disintegration test results Figure 6 As shown in the figure, the erosion resistance of the sample has been improved to a certain extent, and the disintegration rate of the sample after immersion in water for 24 hours is 27.36%. The direct shear test results are shown in Fig.11 As shown in the figure, the cohesion of the sample is 50.25 kPa and the internal friction angle is 26.83°.

[0050] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention should fall within the scope of the present invention.

Claims

1. A method for repairing earthen ruins using bio-mud, characterized in that: The following steps are involved: (1) Mixing the urease-producing bacteria liquid and the cementing liquid, stirring them continuously, letting them stand, and removing the supernatant to obtain the biological mud; (2) Mix the bio-mud, the cementing liquid and the soil of the site to be repaired and stir them evenly to prepare the repair filler; (3) Select bamboo strips that have been soaked in salt water and steamed at high temperature to construct a support frame in layers in the area to be repaired and fill it with repair fillers. Use the remaining repair fillers to fill the gaps at the edges; (4) Mix the bean enzyme solution and the binder solution to prepare the biological treatment solution, and spray the biological treatment solution on the repair area and its surrounding surfaces several times for maintenance.

2. The method according to claim 1, characterized in that: The cementing liquid is a mixed liquid containing urea and CaCl2 in equal molar concentrations.

3. The method according to claim 1, characterized in that: The volume ratio of the urease-producing bacteria liquid and the binder liquid in step (1) is 3:1-7:1, the concentration of the binder liquid is 4.0 mol / L, the stirring time is 8-12 h, and the standing time is 4-6 h.

4. The method according to claim 1, characterized in that: In step (2), the mass ratio of the binder, the bio-mud, and the soil of the ruins to be repaired is 1:1:8-3:1:16; the concentration of the binder is 2.0-4.0 mol / L, and the moisture content of the repair filler is 25-30%.

5. The method according to claim 1, characterized in that: The bamboo strips described in step (3) are freshly cut bamboo strips that are first soaked in salt water with a concentration of 5% to 10% for 1 to 2 days, dried in the shade, and then boiled in boiling water at 100° C. for 6 to 12 hours.

6. The method according to claim 1, characterized in that: The compaction degree of the repair filler in step (3) is not less than 90%.

7. The method according to claim 1, characterized in that: In step (4), the soybean enzyme solution and the binder solution are mixed in a volume ratio of 1:1, and the concentration of the binder solution is 2.0 mol / L.

8. The method according to claim 1, characterized in that: The soybean enzyme solution in step (4) is prepared by stirring raw soybean powder and water for 30 minutes, standing at 4°C for 12-24 hours, and separating the upper suspension to obtain the soybean enzyme solution. The amount of raw soybean powder used is 80-100 g / L.

9. The method according to claim 1, characterized in that: The spraying volume of the biological treatment liquid in step (4) is 2~2.5L / m 2 / Second-rate.

10. The method according to claim 1, characterized in that: In step (4), the biological treatment liquid is sprayed 3 to 7 times, and the time interval between each spraying is 24 hours.

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