Method for preventing surface sliding and erosion of sand soil slope

Abstract

The application discloses a method for preventing and treating surface sliding of sand soil slope and resisting erosion, which is characterized by the following steps: using the synergistic mechanism of MICP combined with sugar-calcium and locust bean gum solution to more fully and efficiently solidify sand soil, so as to achieve the effects of preventing and treating surface sliding of sand soil slope and resisting erosion, and the purposes of enhancing the solidification strength of sand soil and resisting natural environment erosion; during the process of solidifying sand soil by sugar-calcium combined with MICP, the metabolic activity and self-regulation mechanism of microorganisms can be controlled, so that the environment change can be better responded to, meanwhile, the locust bean gum solution forms a gel structure on the surface of sand soil, the permeability resistance of sand soil is enhanced, the sand soil erosion resistance is improved, and the sand soil is more stable when responding to the natural environment erosion; the application adopts green and environment-friendly materials, is suitable for reinforcing large-area sand soil area, has very remarkable solidification effect, has the excellent characteristics of resisting natural environment erosion, and is widely applied to the fields of slope solidification and protection.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of geotechnical engineering and geological engineering, and particularly relates to a method for preventing surface sliding and erosion of a sand slope. BACKGROUND

[0002] When a sand slope is excavated by adopting a slope, due to the characteristics of weak inter-particle adhesion and relatively small internal friction angle of sand, improper excavation or too fast excavation speed may cause stress redistribution of the slope, and the slope is prone to sliding. Long-time rainfall erosion may change the shape of the sand slope, and the rainfall seeps into the slope and is not easily discharged quickly. The sand may generate seepage force in the soil body under long-time rainwater soaking, and then may be softened, so as to form high pore water pressure in the soil body, reduce the effective stress of the soil body, and affect the stability of the slope. Meanwhile, the rainfall may seep into the slope through cracks on the slope surface, which may cause crack expansion, and the crack expansion may further promote water seepage, forming a vicious cycle and posing a great hidden danger to the stability of the sand slope. Therefore, it is crucial to timely implement temporary support measures and improve the water flow erosion resistance of the slope surface when the sand slope is excavated, which makes it an important topic to prevent the problem of slight disturbance of the sand slope during construction causing surface sliding and rainfall erosion of the slope.

[0003] At present, the traditional temporary support measures for ensuring the stability of the sand slope during excavation mainly include anchor rod support, soil nailing wall, steel sheet pile, underground diaphragm wall, prestressed anchor cable, geotextile, etc. The production and use of traditional support structures such as concrete and steel consume high energy and large natural resources, and produce exhaust gas and slag, which pollute the environment. In addition, the construction of traditional support structures such as driven piles and retaining walls is difficult, and requires large machinery and complex construction technology, especially in complex terrain sand slopes, which further leads to high material and construction costs. At the same time, the traditional protection technology does not fully consider the stability of the entire slope and the water flow erosion resistance of the slope surface. Therefore, more effective solutions should be sought for application engineering.

[0004] For the microbial solidification method, microorganisms can precipitate some crystalline and non-crystalline inorganic compounds through metabolism, which play a filling and cementing role in the soil body, and then improve the soil body properties, but the solidification efficiency is relatively low, which limits the application speed and efficiency of the method in actual engineering.

[0005] The patent application file with publication number CN 118498334 A discloses a method for reinforcing loess based on plant urease, which adopts a mixing method to fully mix soil material with sodium-based montmorillonite (Na-Mt); extracts soybean urease and prepares a cementing solution to form a solidification liquid, which is injected into the mixed soil material by a one-time injection method to solidify the loess, which helps to improve the strength of the solidified soil body; but EICP solidification does not rely on microorganisms, lacks metabolic activity and self-regulation mechanism of microorganisms, and cannot respond to environmental changes like MICP using the adaptability of microorganisms; at the same time, EICP solidification does not provide nucleation sites for the generated calcium carbonate, and the aggregation form of calcium carbonate is chaotic, resulting in high brittleness of the solidified soil body and easy brittle failure.

[0006] Zhang YJ et al. (Zhang YJ, Yan DQ, Qu J, et al. Research Progress of Microbial Induced Carbonate Precipitation (MICP) Solidification of Soil [J]. Civil Engineering, 2024, 13(5): 9. DOI:10.12677 / hjce.2024.135065.) proposed the research progress of microbial induced carbonate precipitation (MICP) solidification of soil, which utilizes urease-producing microorganisms to hydrolyze urea to obtain carbonate ions, and then the carbonate ions and calcium ions react to produce CaCO3 precipitate, which can quickly cement soil particles together to achieve soil reinforcement and reduce permeability; but in MICP solidification, due to the differences in pore structure and permeability of the soil, the diffusion of the bacterial solution and the cementing solution in the soil may not be uniform, resulting in better solidification effect in some areas and poor solidification effect in other areas; at the same time, the activity of microorganisms may decrease over time, affecting the generation rate and amount of calcium carbonate precipitate. SUMMARY

[0007] In order to overcome the defects of the prior art, the purpose of the present application is to provide a method for preventing and treating surface sliding and erosion resistance of sand soil slope, which utilizes the synergistic mechanism of MICP combined with sugar calcium and locust bean gum solution to more fully and efficiently solidify the sand soil body, thereby achieving the effect of preventing and treating surface sliding and erosion resistance of sand soil slope, and enhancing the solidification strength of sand soil body and resisting natural environmental erosion; the metabolic activity and self-regulation mechanism of microorganisms can be controlled during the process of sugar calcium combined with MICP solidification of sand soil body, thereby better responding to environmental changes, and the locust bean gum solution forms a gel-like structure on the surface of the sand soil, enhancing the impermeability of the sand soil body and improving the sand soil erosion resistance, making the sand soil body more stable in response to natural environmental erosion; the present application uses green and environmentally friendly materials, is suitable for reinforcing large areas of sand soil, has very significant solidification effect, and has excellent properties of resisting natural environmental erosion.

[0008] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows:

[0009] A method for preventing surface sliding and erosion of sand soil slope, comprising the following steps:

[0010] Step 1: drying natural aeolian sand, and filtering the dried aeolian sand through a 0.5-1 mm sieve to obtain a sand soil sample with impurities removed;

[0011] Step 2: mixing and stirring the bacterial solution and the cementing solution according to a volume ratio of 1:1, 1:2, 2:1 or 2:3 to prepare a solidification liquid;

[0012] Step 3: weighing a certain amount of the sand soil sample prepared in Step 1, adding the solidification liquid prepared in Step 2, which accounts for 15-20% of the mass of the sand soil sample, and uniformly mixing to obtain a sand soil material;

[0013] Step 4: adding calcium sugar, which accounts for 3-8% of the mass of the sand soil sample, to the sand soil material obtained in Step 3, and uniformly mixing to obtain a calcium sugar-sand soil material;

[0014] Step 5: compacting the calcium sugar-sand soil material obtained in Step 4 in 2-4 layers, with a compacting height of 20-40 mm, scraping the layers to treat the layers, and placing and curing at 35-40℃ for 5-7 days;

[0015] Step 6: spraying a locust bean gum solution, which accounts for 7-25% of the mass of the sand soil sample, on the surface of the calcium sugar-sand soil material after the static curing and maintenance in Step 5, and placing and curing at 35-40℃ for 24-36 h to obtain a solidified sand soil body.

[0016] The preparation method of the bacterial solution in Step 2 is as follows:

[0017] In a sterile environment, 0.1-0.3 g of Bacillus pasteurii is inoculated into 50-100 mL of liquid culture medium, and placed in a constant temperature shaking incubator at 30-40℃ and 130-180 rpm for activation culture; when the liquid culture medium becomes turbid, the activation culture of Bacillus pasteurii is the second generation of Bacillus pasteurii; the second generation of Bacillus pasteurii and glycerol are uniformly mixed according to a volume ratio of (5-7):(3-5), and then the mixed second generation of Bacillus pasteurii-glycerol mixture is placed into liquid culture medium according to a volume ratio of (1-2):(100-300) for mixing, and finally placed in a constant temperature shaking incubator at 30-40℃ and 130-180 rpm for culture to obtain a bacterial solution;

[0018] The preparation method of the liquid culture medium is as follows:

[0019] Manganese sulfate, nickel chloride, ammonium chloride, yeast extract and deionized water are uniformly mixed according to the mass ratio (1-2) : (1-2) : (1000-2000) : (2000-4000) : (100000-200000), adjusted to pH = 8.0-9.0 with NaOH solution, heated and sterilized in steam for 30-45 min, and then cooled at room temperature for later use.

[0020] The preparation method of the cementing solution in step 2 is as follows:

[0021] Equal-concentration and equal-volume urea solution and anhydrous calcium chloride solution are uniformly mixed to obtain a cementing solution with a concentration of 0.5-2 mol / L.

[0022] The preparation method of the locust bean gum solution in step 6 is as follows:

[0023] Locust bean gum and deionized water are uniformly mixed according to the mass ratio 1 : (100-200).

[0024] The beneficial effects of the present application are as follows:

[0025] (1) The present application uses MICP to combine with sugar calcium and locust bean gum solution to solidify sand, uses Bacillus pasteurii to secrete urease under suitable environmental conditions, urease catalyzes the hydrolysis of urea to produce carbonate ions and ammonium ions, the carbonate ions produced by hydrolysis combine with calcium ions produced by the hydrolysis of calcium chloride to form calcium carbonate precipitate, and the calcium carbonate precipitate plays a cementing role between sand particles. 2+ , which can help to bond between particles, and sugar calcium can also promote microbial growth and adjust the reaction environment; the locust bean gum solution has good adhesion and can form a dense gelatinous protective film on the surface of sand particles, effectively improving the erosion resistance of sand soil through physical adhesion, water property adjustment and mechanical property enhancement, and through the combined action mechanism of MICP, sugar calcium and locust bean gum solution, the surface sliding of sand slope and erosion resistance are achieved, and the advantages of enhancing the solidification strength of sand soil and resisting natural environmental erosion are achieved.

[0026] (2) Compared with traditional reinforcement methods, the combined action of MICP, sugar calcium and locust bean gum solution on sand soil can significantly improve the solidification effect, enhance the erosion resistance and improve the natural environmental erosion resistance to achieve long-term stability, and can achieve green environmental protection, no pollution and sustainable use of resources, especially when reinforcing a large area.

[0027] (3) Compared with the EICP solidification method, the sugar calcium of the present application utilizes its own properties to synergistically cement the sand soil body with MICP. Compared with the EICP technology for solidifying the sand soil body, the sugar calcium combined with MICP can control the metabolic activity and self-regulation mechanism of the microorganisms during the process of solidifying the sand soil body, so as to better respond to environmental changes. At the same time, the reaction rate of generating calcium carbonate precipitate by the sugar calcium combined with MICP technology is more easily controlled than the EICP technology, and the generated calcium carbonate precipitate is more uniform. In addition, the locust bean gum solution forms a gel-like structure on the surface of the sand soil, enhances the permeability resistance of the sand soil body, improves the sand soil erosion resistance, and makes the sand soil body more stable when responding to natural environmental erosion.

[0028] (4) Compared with the single MICP solidification method, the addition of sugar calcium in the present application ensures that the MICP reaction is more fully carried out in the entire sand soil body, avoiding the occurrence of local solidification unevenness. The solidified sand soil structure is more stable and has higher strength. The sand soil body solidified by the single MICP technology has weaker resistance to natural environmental erosion. With the addition of the locust bean gum solution, a gel-like structure is formed on the surface of the sand soil body, which can effectively block the scouring of water flow, reduce the erosion force, and significantly improve the sand soil erosion resistance.

[0029] In summary, the present application utilizes the coordinated action mechanism of MICP combined with sugar calcium and locust bean gum solution to more fully and efficiently solidify the sand soil body, so as to achieve the effects of preventing and treating the surface sliding of the sand soil slope and resisting erosion, and to enhance the solidification strength of the sand soil body and the resistance to natural environmental erosion. At the same time, sugar calcium and locust bean gum are natural substances, which are pollution-free to the environment, sustainable in resource utilization, and can be widely applied in the fields of slope solidification and protection. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 The preparation flow chart of the present application for solidifying the sand soil body;

[0031] Figure 2 The sand soil sample particle size distribution graph after weathering and removing impurities of the present application;

[0032] Figure 3 The calcium carbonate generation amount and unconfined compressive strength control graph of the MICP combined with sugar calcium orthogonal test of the present application; wherein, Figure 3 (a) in the calcium carbonate generation amount and unconfined compressive strength control graph of the bacteria solution and the cementing solution with a volume ratio of 1:1; Figure 3 (b) in the calcium carbonate generation amount and unconfined compressive strength control graph of the bacteria solution and the cementing solution with a volume ratio of 1:2; Figure 3 (c) in the calcium carbonate generation amount and unconfined compressive strength control graph of the bacteria solution and the cementing solution with a volume ratio of 2:1; Figure 3 (d) in the calcium carbonate generation amount and unconfined compressive strength control graph of the bacteria solution and the cementing solution with a volume ratio of 2:3;

[0033] Figure 4 The peak value and stress-strain curve diagram of the MICP combined with sugar-calcium reinforced sample of the application; wherein, Figure 4 (a) in the figure is the peak value and stress-strain curve diagram of the volume ratio of bacteria liquid to cementing liquid being 1:1; Figure 4 (b) in the figure is the peak value and stress-strain curve diagram of the volume ratio of bacteria liquid to cementing liquid being 1:2; Figure 4 (c) in the figure is the peak value and stress-strain curve diagram of the volume ratio of bacteria liquid to cementing liquid being 2:1; Figure 4 (d) in the figure is the peak value and stress-strain curve diagram of the volume ratio of bacteria liquid to cementing liquid being 2:3;

[0034] Figure 5 The test mold schematic diagram and physical diagram of the application; wherein, Figure 5 (a) in the figure is the test mold schematic diagram; Figure 5 (b) in the figure is the test mold physical diagram;

[0035] Figure 6 The original state sand soil slope model schematic diagram of the application;

[0036] Figure 7 The improved sand soil slope model schematic diagram of the application;

[0037] Figure 8 The slope model scouring test device schematic diagram;

[0038] Figure 9 The original state sand soil slope model rainfall scouring test diagram of the application; wherein, Figure 9 (a) in the figure is the test diagram of the original state sand soil slope model after rainfall scouring for 30 min; Figure 9 (b) in the figure is the test diagram of the original state sand soil slope model after rainfall scouring for 60 min; Figure 9 (c) in the figure is the test diagram of the original state sand soil slope model after rainfall scouring for 90 min; Figure 9 (d) in the figure is the test diagram of the original state sand soil slope model after rainfall scouring for 120 min; Figure 9 (e) in the figure is the test diagram of the original state sand soil slope model after rainfall scouring for 150 min; Figure 9 (f) in the figure is the test diagram of the original state sand soil slope model after rainfall scouring for 180 min;

[0039] Figure 10 The broken line data diagram of the surface and internal erosion amount of the original state sand soil slope after rainfall erosion of the application;

[0040] Figure 11 The broken line data diagram of the cumulative erosion amount of the original state sand soil slope after rainfall erosion of the application;

[0041] Figure 12 Figure 1 is a diagram of a modified sand slope model rainfall erosion test according to the present application; Figure 12 Figure 1(a) is a diagram of the modified sand slope model after 30 minutes of rainfall erosion according to the present application; Figure 12 Figure 1(b) is a diagram of the modified sand slope model after 60 minutes of rainfall erosion according to the present application; Figure 12 Figure 1(c) is a diagram of the modified sand slope model after 90 minutes of rainfall erosion according to the present application; Figure 12 Figure 1(d) is a diagram of the modified sand slope model after 120 minutes of rainfall erosion according to the present application; Figure 12 Figure 1(e) is a diagram of the modified sand slope model after 150 minutes of rainfall erosion according to the present application; Figure 12 Figure 1(f) is a diagram of the modified sand slope model after 180 minutes of rainfall erosion according to the present application.

[0042] Figure 13 Figure 2 is a broken line data graph of the surface and internal erosion amount of the modified sand slope after rainfall erosion according to the present application;

[0043] Figure 14 Figure 3 is a broken line data graph of the cumulative erosion amount of the modified sand slope after rainfall erosion according to the present application;

[0044] Figure 15 Figure 4 is a flow rate change bar graph of the original sand slope model and the modified sand slope model according to the present application. DETAILED DESCRIPTION

[0045] The method, process and effects of the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings and the written description of the present application.

[0046] Embodiment 1

[0047] Referring to Figure 1 A method for preventing surface sliding and erosion of a sand slope, specifically comprising the following steps:

[0048] Step 1: Dry natural aeolian sand, then filter it through a 0.5 mm sieve to obtain a sand sample with impurities removed;

[0049] According to the "Code for Testing of Soil and Rock", the mechanical property parameters of the sand sample are determined. After the natural aeolian sand is dried, particles larger than 1 mm and impurities are removed. The content of particles with a particle size of 0.05 mm to 0.5 mm is 96%, and the dry density is 1.52 g / cm 3 , Cu = 2.25, C c = 0.73, and the particle size distribution of the sand sample is shown in Figure 2 ;

[0050] Step 2: Mix the bacteria solution and the cementing solution in a volume ratio of 1:1 and stir to prepare a solidification liquid;

[0051] The bacteria solution preparation method is:

[0052] In a sterile environment, 0.1 g of Sporosarcina pasteurii is inoculated into 50 mL of liquid culture medium, and is placed in a constant temperature shaking incubator at 30℃ and 180 rpm for activation culture. When the liquid culture medium becomes turbid, the activation culture of Sporosarcina pasteurii is the second generation Sporosarcina pasteurii. The second generation Sporosarcina pasteurii is uniformly mixed with glycerol at a volume ratio of 7:3, and then the mixed second generation Sporosarcina pasteurii-glycerol mixture is placed into the liquid culture medium at a volume ratio of 1:100 for mixing. Finally, it is placed in a constant temperature shaking incubator at 30℃ and 180 rpm for culture to obtain the bacteria solution.

[0053] The preparation method of the liquid culture medium is:

[0054] Manganese sulfate, nickel chloride, ammonium chloride, yeast extract and deionized water are uniformly mixed at a mass ratio of 1:1:1000:2000:100000. A 1 mol / L NaOH solution is used to adjust the pH to 9.0. After heating sterilization in steam for 35 min, it is cooled to room temperature for later use.

[0055] The preparation method of the cementing solution is:

[0056] Equal concentration and equal volume of urea solution and anhydrous calcium chloride solution are uniformly mixed to obtain a cementing solution with a concentration of 1 mol / L.

[0057] Step 3: A certain mass of the sand sample prepared in step 1 is weighed, and the solidification liquid prepared in step 2 is added at a mass ratio of 17% of the sand sample, and uniformly mixed to obtain a sand material.

[0058] Step 4: Add sugar calcium to the sand material obtained in step 3 at a mass ratio of 3% of the sand sample, and uniformly mix to obtain a sugar calcium-sand material.

[0059] The sugar calcium is obtained through a commercial channel (brand: Qingjun, model: retarder and water reducer). It is a brown yellow powder solid prepared from waste materials (waste molasses, vinasse) of sugar factories. It is a high molecular electrolyte with a molecular weight of 1000-100000, and the dispersibility of 10000-40000 is particularly effective. Sugar calcium has strong decomposition, adhesion and cementation.

[0060] Sugar calcium is mainly divided into sucrose calcium complex and monosaccharide calcium complex. The dissolution in water releases sticky substances (monosaccharides and sucrose) and Ca 2+ , which helps to bond between sand particles, and sugar calcium can also promote microbial growth and adjust the reaction environment.

[0061] Step 5: The sugar-calcium-sand soil material obtained in step 4 is compacted in three layers, each layer with a height of 27 mm, and the layers are scraped and treated between layers, and cured at 35℃ for 7 days;

[0062] Step 6: After the sugar-calcium-sand soil material is cured at 35℃ for 36h, a solution of locust bean gum is sprayed on the surface of the sand soil sample, with a mass ratio of 12%, and the cured sand soil body is obtained after 36h of curing at 35℃;

[0063] The preparation method of the locust bean gum solution is:

[0064] The locust bean gum and deionized water are uniformly mixed in a mass ratio of 1:100.

[0065] Example 2

[0066] A method for preventing and controlling the surface sliding and erosion resistance of sand soil slope, specifically comprising the following steps:

[0067] Step 1: The natural aeolian sand is dried, then filtered through a 0.7mm sieve to obtain a sand soil sample with impurities removed;

[0068] Step 2: Mix the bacteria solution and the cementing solution in a volume ratio of 1:2 and stir to prepare a curing liquid;

[0069] The preparation method of the bacteria solution is:

[0070] In a sterile environment, 0.2g of Bacillus pasteurii is inoculated into 50mL of liquid culture medium, and placed in a constant temperature shaking incubator at 35℃ and 170rpm for activation culture. When the liquid culture medium becomes turbid, the activation culture of Bacillus pasteurii is the second generation of Bacillus pasteurii. The second generation of Bacillus pasteurii and glycerol are uniformly mixed in a volume ratio of 6:4, and then the mixed second generation of Bacillus pasteurii-glycerol mixture is placed in the liquid culture medium in a volume ratio of 1.5:200. Finally, it is placed in a constant temperature shaking incubator at 35℃ and 170rpm for culture to obtain the bacteria solution;

[0071] The preparation method of the liquid culture medium is:

[0072] Manganese sulfate, nickel chloride, ammonium chloride, yeast extract and deionized water are uniformly mixed in a mass ratio of 1:1.5:2000:3000:150000, and adjusted to pH=8.5 with 1moL / L NaOH solution. After heating sterilization in steam for 30min, it is cooled to room temperature for later use;

[0073] The preparation method of the cementing solution is:

[0074] The urea solution and anhydrous calcium chloride solution are uniformly mixed in equal concentration and equal volume to obtain a cementing solution with a concentration of 0.5mol / L;

[0075] Step 3: A certain mass of the sand sample prepared in step 1 is weighed, and the solidification liquid prepared in step 2 is added at a mass ratio of 18% of the sand sample, and uniformly mixed to obtain a sand material;

[0076] Step 4: The sand material obtained in step 3 is added with sugar-calcium at a mass ratio of 5% of the sand sample, and uniformly mixed to obtain a sugar-calcium-sand material;

[0077] Step 5: The sugar-calcium-sand material obtained in step 4 is compacted in 4 layers, each layer with a compacting height of 20mm, and the layers are scraped to treat the surface between the layers, and then placed at 37℃ for 6 days of curing and maintenance;

[0078] Step 6: The surface of the sugar-calcium-sand material after curing and maintenance in step 5 is sprayed with a locust bean gum solution at a mass ratio of 25% of the sand sample, and then placed at 37℃ for 30h of curing and maintenance to obtain a solidified sand body;

[0079] The preparation method of the locust bean gum solution is as follows:

[0080] The locust bean gum and deionized water are uniformly mixed at a mass ratio of 1:150.

[0081] Example 3

[0082] A method for preventing and treating surface sliding and erosion resistance of sand slope, specifically comprising the following steps:

[0083] Step 1: The natural aeolian sand is dried, and then filtered through a 0.9mm sieve to obtain a sand sample with impurities removed;

[0084] Step 2: The bacteria solution and the cementing solution are mixed and stirred at a volume ratio of 2:1 to prepare a solidification liquid;

[0085] The preparation method of the bacteria solution is as follows:

[0086] In a sterile environment, 0.2g of Bacillus circulans is inoculated into 100mL of liquid culture medium, and then placed in a constant temperature shaking incubator at 40℃ and 160rpm for activation culture. When the liquid culture medium becomes turbid, the activation culture of the Bacillus circulans is the second generation of Bacillus circulans. The second generation of Bacillus circulans and glycerol are uniformly mixed at a volume ratio of 5:5, and then the mixed second generation of Bacillus circulans-glycerol mixture is placed in the liquid culture medium at a volume ratio of 2:300 for mixing. Finally, the mixture is placed in a constant temperature shaking incubator at 40℃ and 160rpm for culture to obtain a bacteria solution;

[0087] The preparation method of the liquid culture medium is as follows:

[0088] Manganese sulfate, nickel chloride, ammonium chloride, yeast extract and deionized water are uniformly mixed according to the mass ratio of 2:2:2000:3000:200000, adjusted to pH=8.0 with 1 mol / L NaOH solution, heated and sterilized in steam for 40 min, and then cooled at room temperature for later use;

[0089] The preparation method of the cementation liquid is:

[0090] The urea solution and the anhydrous calcium chloride solution are uniformly mixed in equal concentration and equal volume to obtain a cementation liquid with a concentration of 1.5 mol / L;

[0091] Step 3: A certain mass of the sand sample prepared in step 1 is weighed, and the solidification liquid prepared in step 2 is added to the sand sample in a mass ratio of 15%, and uniformly mixed to obtain a sand material;

[0092] Step 4: The sand material obtained in step 3 is added with sugar-calcium in a mass ratio of 6% of the sand sample, and uniformly mixed to obtain a sugar-calcium-sand material;

[0093] Step 5: The sugar-calcium-sand material obtained in step 4 is compacted in three layers, each layer with a compacting height of 27 mm, and the layers are scraped to treat the layers, and then placed at 39°C for 5 days of curing and maintenance;

[0094] Step 6: The surface of the sugar-calcium-sand material after curing and maintenance in step 5 is sprayed with a locust bean gum solution in a mass ratio of 7% of the sand sample, and then placed at 39°C for 24 hours of curing and maintenance to obtain a solidified sand body;

[0095] The preparation method of the locust bean gum solution is:

[0096] The locust bean gum and deionized water are uniformly mixed according to the mass ratio of 1:200.

[0097] Example 4

[0098] A method for preventing and treating surface sliding and erosion resistance of sand slope, specifically comprising the following steps:

[0099] Step 1: The natural aeolian sand is dried, and then filtered through a 0.5 mm sieve to obtain a sand sample with impurities removed;

[0100] Step 2: The bacteria solution and the cementation liquid are mixed and stirred according to a volume ratio of 2:3 to prepare a solidification liquid;

[0101] The preparation method of the bacteria solution is:

[0102] In a sterile environment, 0.2 g of Sporosarcina pasteurii was inoculated into 50 mL of liquid culture medium, and was placed in a constant temperature shaker at 35℃ and 150 rpm for activation culture. When the liquid culture medium became turbid, the activation culture of Sporosarcina pasteurii was the second generation of Sporosarcina pasteurii; the second generation of Sporosarcina pasteurii was uniformly mixed with glycerol at a volume ratio of 5:3, and then the mixed second generation of Sporosarcina pasteurii-glycerol mixture was mixed into the liquid culture medium at a volume ratio of 2:100. Finally, the mixture was placed in a constant temperature shaker at 35℃ and 150 rpm for culture to obtain a bacterial solution;

[0103] The preparation method of the liquid culture medium is:

[0104] Manganese sulfate, nickel chloride, ammonium chloride, and yeast extract were uniformly mixed with deionized water at a mass ratio of 2:1:1000:4000:200000. Then, 1 mol / L NaOH solution was used to adjust the pH to 9.0. The mixture was heated and sterilized in steam for 45 min, and then cooled to room temperature for later use.

[0105] The preparation method of the cementing liquid is:

[0106] Equal-concentration and equal-volume urea solution and anhydrous calcium chloride solution were uniformly mixed to obtain a cementing liquid with a concentration of 1 mol / L.

[0107] Step 3: A certain mass of the sand sample prepared in step 1 was weighed, and the solidification liquid prepared in step 2 was added at a mass ratio of 20% of the sand sample, and uniformly mixed to obtain a sand material.

[0108] Step 4: Sugar-calcium was added to the sand material obtained in step 3 at a mass ratio of 6% of the sand sample, and uniformly mixed to obtain a sugar-calcium-sand material.

[0109] Step 5: The sugar-calcium-sand material obtained in step 4 was compacted in two layers, each with a compacting height of 40 mm, and the layers were treated with a scraping process. The compacted material was placed at 40℃ for 7 days of curing and maintenance.

[0110] Step 6: A locust bean gum solution was sprayed on the surface of the sugar-calcium-sand material obtained in step 5 after curing and maintenance, at a mass ratio of 10% of the sand sample. The compacted material was placed at 40℃ for 36 h of curing and maintenance to obtain a solidified sand body.

[0111] The preparation method of the locust bean gum solution is:

[0112] Locust bean gum and deionized water were uniformly mixed at a mass ratio of 1:180.

[0113] Example 5

[0114] A method for preventing and controlling the surface sliding and erosion resistance of a sand slope, specifically comprising the following steps:

[0115] Step 1: Dry the natural aeolian sand, and then filter it through a 1.0 mm sieve to obtain a sample of the sand soil with impurities removed;

[0116] Step 2: Mix the bacterial solution and the cementing solution in a volume ratio of 1:1 and stir to prepare a solidifying solution;

[0117] The bacterial solution is prepared by:

[0118] In a sterile environment, 0.1 g of Sporosarcina pasteurii is inoculated into 100 mL of liquid culture medium, and then placed in a constant temperature shaking incubator at 30℃ and 130 rpm for activation culture. When the liquid culture medium becomes turbid, the activation culture of Sporosarcina pasteurii is the second generation of Sporosarcina pasteurii. The second generation of Sporosarcina pasteurii is uniformly mixed with glycerol at a volume ratio of 5:4, and then the mixed second generation of Sporosarcina pasteurii-glycerol mixture is mixed with liquid culture medium at a volume ratio of 1:300. Finally, it is placed in a constant temperature shaking incubator at 30℃ and 130 rpm for culture to obtain the bacterial solution;

[0119] The preparation method of the liquid culture medium is:

[0120] Manganese sulfate, nickel chloride, ammonium chloride, yeast extract and deionized water are uniformly mixed at a mass ratio of 2:2:2000:3000:200000. Then, 1 moL / L NaOH solution is used to adjust the pH to 8.5. The mixture is heated and sterilized in steam for 35 min, and then cooled to room temperature for later use;

[0121] The preparation method of the cementing solution is:

[0122] Equal-concentration and equal-volume urea solution and anhydrous calcium chloride solution are uniformly mixed to obtain a cementing solution with a concentration of 2 mol / L;

[0123] Step 3: A certain mass of the sand soil sample prepared in step 1 is weighed, and the solidifying solution prepared in step 2 is added to the sand soil sample at a mass ratio of 17%, and then uniformly mixed to obtain a sand soil material;

[0124] Step 4: Sugar-calcium is added to the sand soil material obtained in step 3 at a mass ratio of 8% of the sand soil sample, and then uniformly mixed to obtain a sugar-calcium-sand soil material;

[0125] Step 5: The sugar-calcium-sand soil material obtained in step 4 is compacted in three layers, each with a compaction height of 27 mm, and the layers are treated by scraping to remove the hair between the layers. The material is placed at 35℃ for 5 days of curing and maintenance;

[0126] Step 6: A locust bean gum solution is sprayed on the surface of the sugar-calcium-sand soil material obtained in step 5 after curing and maintenance, and the mass ratio of the locust bean gum solution to the sand soil sample is 13%. The material is placed at 35℃ for 28 h of curing and maintenance to obtain a solidified sand soil body;

[0127] The preparation method of the locust bean gum solution is:

[0128] Mix locust bean gum and deionized water uniformly at a mass ratio of 1:200.

[0129] Test verification

[0130] To explore the key influencing factors and effects of the application in preventing and treating surface sliding and erosion resistance of sandy soil slope, orthogonal test verification is designed from two aspects of MICP combined with sugar-calcium solidification and MICP combined with sugar-calcium and locust bean gum solution solidification.

[0131] Key influencing factors and effects of sugar-calcium combined with MICP solidification of sandy soil are explored: by considering the volume ratio of mixed solution of bacterial liquid and cementing liquid (1:1, 1:2, 2:1, 2:3), cementing liquid concentration (0.5 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L), mass ratio of solidification liquid added into sandy soil sample (15%, 17%, 18%, 20%), and sugar-calcium addition amount (3%, 5%, 6%, 8%) four factors, the following experiment is designed:

[0132] The test scheme is shown in Table 1 as follows:

[0133] Table 1 Key influencing factor orthogonal test scheme of MICP combined with sugar-calcium solidification of sandy soil

[0134]

[0135]

[0136] According to the requirements of the test scheme in Table 1, the mixed solution of bacterial liquid and cementing liquid is mixed and stirred according to the volume ratio of 1:1, 1:2, 2:1, 2:3 to prepare the solidification liquid, a certain mass of sandy soil sample is weighed, and 15% to 20% of the solidification liquid and 3% to 8% of the sugar-calcium in the mass ratio of the sandy soil sample are added into the sandy soil sample to uniformly mix to obtain the sugar-calcium-sandy soil material; the sugar-calcium-sandy soil material is layered and compacted, the layers are scraped and treated, and the curing is placed.

[0137] The sugar-calcium-sandy soil material prepared in the above test scheme is taken, and 1 mol / L hydrochloric acid is used for sufficient acid washing to measure the content of calcium carbonate. The specific operation is as follows: a certain amount of sugar-calcium-sandy soil material after solidification and curing is accurately weighed and put into a conical flask, and enough dilute hydrochloric acid is added into the conical flask, so that the calcium carbonate in the sample reacts with the hydrochloric acid to generate carbon dioxide gas, the reaction condition of the sample and the acid is observed, the carbon dioxide gas generated in the reaction will form bubbles, after no bubbles are observed, a small amount of distilled water is used to wash the filter residue, to ensure that all the soluble substances enter the filtrate, and then the filter residue is placed in a dryer to dry and weigh, and the mass of the dried filter residue is subtracted from the mass of the original sample, that is, the generated amount of calcium carbonate reacted.

[0138] According to GB / T50123-2019 "Standard for Soil Test Methods", the unconfined compressive strength test of the sugar-calcium-sand soil material prepared by the above test scheme and cured after standing is carried out by using a strain control type unconfined compression testing machine with a set value of loading rate of 1 mm / min, and the compressive strength of different sugar-calcium-sand soil materials is obtained.

[0139] Table 2 Calcium carbonate generation amount and compressive strength of MICP combined with sugar-calcium orthogonal test

[0140]

[0141] According to the data analysis of Table 2, the influence of the amount of sugar-calcium added to the sand and the mass ratio of the curing liquid added to the sand on the strength of the sand material and the calcium carbonate generation amount plays a major role, the influence of the cementing liquid concentration and the volume ratio of the mixed liquid of the bacterial liquid and the cementing liquid on the strength of the sand material and the calcium carbonate generation amount is smaller, and thus the influence of the above three factors on the strength of the sand material and the calcium carbonate generation amount is in the order of the amount of sugar-calcium added to the sand > the mass ratio of the curing liquid added to the sand > the cementing liquid concentration > the volume ratio of the mixed liquid of the bacterial liquid and the cementing liquid.

[0142] With the increase of the amount of sugar-calcium added, the strength and calcium carbonate content of the sample have a large increase, and the strength and calcium carbonate content of the sample generally show a positive correlation. According to the analysis of (a)-(d) in Table 2 and Figure 3 , when the amount of sugar-calcium added is 5%, it breaks through 3000 kPa, when the amount is 6%, it reaches the peak value of 3310 kPa, and when the amount is 8%, the strength is close to that when the amount is 6%, which is increased by about 1418% compared with the compressive strength of the sand sample without adding curing material; when the amount reaches 6%, the calcium carbonate content can reach 17.1%, which is because sugar-calcium will dissolve in the liquid and decompose free Ca 2 + , providing a more sufficient calcium source for the microbial process.

[0143] No matter what the amount of sugar-calcium-sand material is, the stress-strain curve of the sugar-calcium-sand material also has a significant value, which is a strain softening type, and mainly exists in three stages of stress rise, stress drop and residual stress. According to the analysis of (a)-(d) in Table 2 and Figure 4 , when the amount of sugar-calcium added is 3%, the influence on the curing effect is small, and the residual strength is about 280 kPa. With the gradual increase of the amount of sugar-calcium added, the curve gradually moves up, when the amount reaches 6%, the strain corresponding to the peak stress of the sample is 0.025%, and the curve slope in the stress rising stage increases obviously, and the sample shows a high residual strength of about 650 kPa in the stress drop stage, indicating that the addition of sugar-calcium improves the deformation resistance to a certain extent, and the contribution to the peak strength is most obvious.

[0144] Preferably, the optimal combination of the MICP combined with sugar-calcium solidified sand in the embodiment is that the volume ratio of the mixed solution of the bacterial solution and the cementing solution is 1:1, the concentration of the cementing solution is 1 mol / L, the mass ratio of the solidification liquid added into the sand is 17%, and the sugar-calcium content in the sand can be 6%.

[0145] According to the optimal combination of the MICP combined with sugar-calcium, an orthogonal test scheme of key influencing factors of the MICP combined with sugar-calcium and locust bean gum solution solidified sand is designed.

[0146] The sugar-calcium-sand material is obtained by uniformly mixing the sand sample solidified by the sugar-calcium with the optimal content of 6%, and the solidification and curing of the surface of the sugar-calcium-sand material after standing, and then spraying the locust bean gum solution (locust bean gum and deionized water are uniformly mixed at a mass ratio of 1:100 or 1:200) accounting for 7%-25% of the mass of the sand sample on the surface of the sugar-calcium-sand material, and then standing and curing to obtain the solidified sand body.

[0147] The test scheme is shown in Table 3 below.

[0148] Table 3 Orthogonal test scheme of key influencing factors of the MICP combined with sugar-calcium and locust bean gum solution solidified sand

[0149]

[0150] According to the orthogonal test scheme of key influencing factors of the MICP combined with sugar-calcium and locust bean gum solution solidified sand in Table 3, the wet disintegration test of the structural solidified sand body prepared by the test scheme is carried out according to SL 237-008-1999 “Wet Test (with Article Description)”, and the disintegration rate in water is determined.

[0151] Table 4 Wet disintegration test results of the MICP combined with sugar-calcium and locust bean gum solution orthogonal test

[0152]

[0153]

[0154] From the disintegration test results of Table 4, it can be seen that the anti-disintegration effects of spraying the locust bean gum solution with a concentration of 1:200 and a locust bean gum amount of 10% of the mass of the sand sample onto the surface of the sugar-calcium sand material, spraying the locust bean gum solution with a concentration of 1:100 and a locust bean gum amount of 12% of the mass of the sand sample, spraying the locust bean gum solution with a concentration of 1:100 and a locust bean gum amount of 20% of the mass of the sand sample, spraying the locust bean gum solution with a concentration of 1:100 and a locust bean gum amount of 25% of the mass of the sand sample, and spraying the locust bean gum solution with a concentration of 1:200 and a locust bean gum amount of 13% of the mass of the sand sample all show a consistent change trend, and the sugar-calcium sand material with different locust bean gum amounts does not disintegrate at all at the same curing age. Meanwhile, the cost of spraying the locust bean gum solution with a concentration of 1:200 and a locust bean gum amount of 10% of the mass of the sand sample onto the surface of the sugar-calcium sand material is as low as 0.6 yuan, and the economic benefit is high.

[0155] Since the locust bean gum is a natural high-molecular polysaccharide material with a structural framework of mannose and galactose, the mannose and galactose in the molecular structure of the locust bean gum have good linking and adhesive properties in water, and can link the soil aggregates together, thereby forming a more stable soil structure. Long-term soaking has little effect on the anti-disintegration properties of the sugar-calcium sand material, and the spraying amount of the locust bean gum plays a decisive role in the anti-disintegration properties of the sugar-calcium sand material.

[0156] In summary, the locust bean gum solution with a concentration of 1:100 (the locust bean gum amount is 12-25% of the mass of the sand) or the locust bean gum solution with a concentration of 1:200 (the locust bean gum amount is 10-13% of the mass of the sand) can be sprayed onto the surface of the sugar-calcium sand material to achieve the effect of completely resisting disintegration, and thus the excellent anti-scouring and anti-erosion properties are achieved.

[0157] Preferably, to achieve the best effect of resisting rainwater scouring and erosion, the locust bean gum solution with a concentration of 1:200 (the locust bean gum amount is 10% of the mass of the sand) is selected.

[0158] To explore the application effect of preventing and treating the surface sliding of the sand slope and resisting scouring and erosion, the inventor of the present application makes a natural sand slope model. A transparent slope mold is designed by using an organic glass plate, as shown in Fig. 1. Figure 5The length, width and height of the slope mold are 34 cm, 24 cm and 14 cm respectively, and the slope ratio of the slope is 1:2. There is a baffle at the slope angle of the slope mold to separate the slope surface and the outflowing material, and the empty groove in front of the baffle can be used to collect the slope surface erosion outflowing material; the bottom of the slope surface is uniformly arranged with 5 mm circular small holes every 1 cm for the outflowing material and moisture through internal erosion. When filling the sample, in order to avoid the standard sand flowing directly from the bottom small holes during the filling process, a layer of coarse gravel is laid on the model and the bottom, and the laying height is consistent with the height of the baffle. The natural aeolian sand is taken in an appropriate amount, dried, and filtered with a 0.5 mm hole screen to obtain the impurity-removed soil sample, and the soil sample (total 7075 g) is filled into the above-mentioned slope mold to obtain the undisturbed soil slope model, as shown in Figure 6 .

[0159] On the basis of the above-mentioned undisturbed soil (total 7075 g) slope model, the volume ratio of bacteria liquid to cementing liquid is 1:1, the cementing liquid concentration is 1 mol / L, the solidified liquid accounts for 17% of the mass of the soil sample, and the sugar calcium accounts for 6% of the mass of the soil sample. The above-mentioned proportions are sequentially added to the soil slope, and after 3 h of penetration, a 1:200 concentration locust bean gum solution accounting for 10% of the mass of the soil sample is sprayed to the outer surface of the sugar calcium-soil material. The treated slope model is placed in a 35℃ environment for curing for 7 days to obtain the improved soil slope model, as shown in Figure 7 .

[0160] The cumulative soil erosion amount and erosion characteristics of the undisturbed soil slope model and the improved soil slope model under rainfall erosion are analyzed by respectively conducting rainfall erosion tests, so as to study the application effect thereof.

[0161] In order to better observe the erosion resistance of the sand soil slope under extreme conditions, the rainfall intensity is 300 mm / h, and the rainfall time is set to 30 min, 60 min, 90 min, 120 min, 150 min and 180 min for testing. The slope model erosion test device is shown in Figure 8 . The slope model erosion test device is composed of a PVC support, a water conveying system, a pressure valve, an on-off valve, and a rainfall nozzle. The rainfall system is set to a height of 1 m, and 5 replaceable types of atomizing nozzles are uniformly arranged at the top. By changing the number and type of the nozzles, the rainfall intensity can be changed. On one side of the PVC support, a water conveying pipe is connected to the top, and tap water is directly supplied. The flow and pressure are controlled by the on-off valve and the pressure valve. The rainfall area covers an area of about 1 square meter.

[0162] Figure 9Fig. 1 is a diagram of the original sand soil slope model rainfall erosion test of the present application, in which six groups of original sand soil slope models are set, the rainfall intensity is 300 mm / h, and the rainfall erosion time is set as 30 min, 60 min, 90 min, 120 min, 150 min and 180 min, respectively. Figure 9 Figs. 1(a)-1(f) are diagrams of the original sand soil slope model after rainfall erosion for 30 min, 60 min, 90 min, 120 min, 150 min and 180 min, respectively.

[0163] Based on the above rainfall erosion test, the rainfall erosion characteristics of the original sand soil slope model are counted, as shown in Table 5.

[0164] Table 5 Rainfall erosion characteristics of the original sand soil slope model

[0165]

[0166]

[0167] Figure 12 Fig. 2 is a diagram of the improved sand soil slope model rainfall erosion test of the present application, in which six groups of improved sand soil slope models are set, the rainfall intensity is 300 mm / h, and the rainfall erosion time is set as 30 min, 60 min, 90 min, 120 min, 150 min and 180 min, respectively. Figure 12 Figs. 2(a)-2(f) are diagrams of the improved sand soil slope model after rainfall erosion for 30 min, 60 min, 90 min, 120 min, 150 min and 180 min, respectively.

[0168] Based on the above rainfall erosion test, the rainfall erosion characteristics of the improved sand soil slope model are counted, as shown in Table 6.

[0169] Table 6 Rainfall erosion characteristics of the improved sand soil slope model

[0170]

[0171] According to the rainfall erosion characteristics of Tables 5 and 6 above, and based on the test of the slope anti-rainfall erosion of the original sand soil slope model and the improved sand soil slope model under the same conditions, the following conclusions are drawn: under the rainfall erosion, not only the surface erosion of the slope, but also the internal erosion caused by the internal flow of the rainfall will cause damage to the slope.

[0172] According to the rainfall erosion characteristics of Table 5 above and Figure 9The analysis of the test figures in (a)-(f) in Table 6 shows that for the undisturbed sand slope model, the surface of the entire slope is severely eroded with the increase of rainfall time, the erosion of the slope develops from the middle of the slope surface, then extends to the inside of the slope, the height of the slope is continuously reduced with time, and finally the slope is completely eroded.

[0173] According to Figure 10 , Figure 11 and Figure 15 , it can be seen that with the increase of rainfall time, the surface erosion of the undisturbed slope model gradually increases, when the rainfall time accumulates to 180 min, the cumulative erosion reaches 5044g, accounting for about 71.3% of the total amount of sand slope, and the surface erosion of the slope reaches 4912g, accounting for about 69.3% of the total amount of sand slope, and the internal erosion of the slope is 152g, accounting for about 2% of the total amount of sand slope, and the rainfall erosion mainly affects the surface of the undisturbed slope model.

[0174] According to the rainfall erosion characteristics in Table 6 above and Figure 12 the analysis of the test figures in (a)-(f) after rainfall erosion shows that for the improved sand slope model, it shows good anti-erosion characteristics compared with the undisturbed sand slope model. The reduction of slope erosion caused by rainfall mainly depends on the good adhesion of locust bean gum solution, which can form a dense gel-like impermeable protective film on the surface of sand particles, which effectively prevents water erosion, and the joint MICP and sugar-calcium reinforcement treatment cements the sand particles together to form a protective shell layer. Under the combined action mechanism of MICP, sugar-calcium and locust bean gum solution, it can effectively prevent the surface sliding of the sand slope due to slight disturbance and rainfall erosion. For the change of slope surface flow and seepage flow of the sand slope model before and after improvement and reinforcement, the improved and reinforced sand slope shows the phenomenon of reduced internal seepage flow and increased surface flow.

[0175] According to Figure 13 , Figure 14 and Figure 15 , it can be seen that the improved sand slope model shows excellent anti-erosion effect under long-time rainfall erosion. When the rainfall time accumulates to 180 min, the cumulative erosion is about 33g, accounting for about 0.43% of the total amount of sand slope, and the surface erosion of the slope is about 31g, accounting for about 0.42% of the total amount of sand slope, and the internal erosion of the slope can be ignored.

[0176] Compared with the cumulative soil erosion of the undisturbed sand slope model under rainfall erosion, the cumulative soil erosion of the improved slope model is reduced by 165 times.

[0177] In summary, the sand soil is solidified by using the sugar calcium combined MICP technology (the volume ratio of the mixed solution of the bacterial solution and the cementing solution is 1:1, the concentration of the cementing solution is 1 mol / L, and the mass ratio of the solidification solution added into the sand soil is 17%) with 6%, and the locust bean gum solution with a concentration of 1:200 (the amount of the locust bean gum solution is 10% of the mass of the sand soil), so that the surface sliding of the sand soil slope and the rain erosion resistance can be effectively prevented.

[0178] From the above examples, compared with the prior art, the following advantages can be obtained:

[0179] The present application solidifies the sand soil by MICP combined with sugar calcium and locust bean gum solution, uses the urease secreted by the Bacillus pasteurii under suitable environmental conditions, the urease catalyzes the hydrolysis of urea to produce carbonate ions and ammonium ions, the carbonate ions produced by hydrolysis combine with the calcium ions produced by the hydrolysis of calcium chloride to form calcium carbonate precipitate, and the calcium carbonate precipitate plays a cementing role between sand soil particles. 2+ The sugar calcium mainly includes sucrose calcium complex and monosaccharide calcium complex, and the dissolution in water releases viscous substances (monosaccharide and sucrose) and Ca

[0180] Compared with the traditional reinforcement method, through the joint action of MICP combined with sugar calcium and locust bean gum solution on the sand soil body, the solidification effect, the anti-erosion performance and the natural environmental erosion resistance are significantly improved to achieve the purpose of long-term stability, and the green and environment-friendly non-pollution and sustainable utilization of resources are achieved, which can be preferentially considered especially when reinforcing a large area.

[0181] Compared with the EICP solidification method, the sugar calcium of the present application utilizes its own properties to synergistically cement the sand soil body with MICP, and compared with the EICP technology for solidifying the sand soil body, the sugar calcium combined with MICP for solidifying the sand soil body can control the metabolic activity and self-regulation mechanism of the microorganisms, so as to better respond to environmental changes; at the same time, the reaction rate of the calcium carbonate precipitate generated by the sugar calcium combined with MICP technology is more easily controlled than the EICP technology, and the calcium carbonate precipitate generated is more uniform; in addition, the locust bean gum solution forms a gel-like structure on the surface of the sand soil, enhances the permeability resistance of the sand soil body, improves the sand soil erosion resistance, and makes the sand soil body more stable when responding to natural environmental erosion.

[0182] Compared with a single MICP solidification method, the addition of sugar calcium ensures that the MICP reaction is more fully carried out in the whole sand body, avoids the occurrence of local solidification unevenness, and the solidified sand structure is more stable and has higher strength; the sand body solidified by the single MICP technology has weak resistance to natural environment erosion, and with the addition of the locust bean gum solution, a gel-like structure is formed on the surface of the sand body, which can effectively block the scouring of water flow, reduce the erosion, and significantly improve the erosion resistance of the sand.

[0183] In summary, the present application utilizes the coordinated action mechanism of MICP combined with sugar calcium and locust bean gum solution to more fully and efficiently solidify the sand body, thereby achieving the effects of preventing and treating the surface layer sliding of the sand slope and resisting erosion, and enhancing the solidification strength of the sand body and the resistance to natural environment erosion; meanwhile, the sugar calcium and locust bean gum are pollution-free to the environment, and the resources are sustainable, so the present application can be widely applied in the fields of slope solidification and protection.

[0184] The above describes the present application and its embodiments, which are not limited, and the embodiments shown in the drawings are only one of the embodiments of the present application. In summary, if a person skilled in the art is inspired by it, without departing from the purpose of the present application, similar structural modes and embodiments can be designed without creative design, which should belong to the protection scope of the present application.

Claims

1. A method for preventing surface sliding and erosion of sandy soil slopes, characterized in that, Specifically comprising the following steps: Step 1: drying natural aeolian sand, and filtering the dried aeolian sand through a 0.5-1 mm sieve to obtain a sand sample with impurities removed; Step 2: mixing and stirring the bacterial solution and the cementing solution in a volume ratio of 1:1, 1:2, 2:1 or 2:3 to prepare a solidification liquid; The bacterial solution is prepared by: In a sterile environment, 0.1-0.3 g of Sporosarcina pasteurii is inoculated into 50-100 mL of liquid culture medium, and is placed in a constant-temperature shaking incubator at 30-40°C and 130-180 rpm for activation culture. When the liquid culture medium becomes turbid, the activation culture of Sporosarcina pasteurii is the second generation of Sporosarcina pasteurii. The second generation of Sporosarcina pasteurii is uniformly mixed with glycerol in a volume ratio of (5-7):(3-5), and then the mixed second generation of Sporosarcina pasteurii-glycerol mixture is mixed with liquid culture medium in a volume ratio of (1-2):(100-300). Finally, the mixture is placed in a constant-temperature shaking incubator at 30-40°C and 130-180 rpm for culture to obtain the bacterial solution. The liquid culture medium is prepared by: Manganese sulfate, nickel chloride, ammonium chloride, yeast extract and deionized water are uniformly mixed in a mass ratio of (1-2):(1-2):(1000-2000):(2000-4000):(100000-200000), and NaOH solution is used to adjust the pH to 8.0-9.

0. The mixture is heated and sterilized in steam for 30-45 min, and then cooled to room temperature for later use. Step 3: weighing a certain amount of the sand sample prepared in step 1, adding the solidification liquid prepared in step 2 in an amount of 15-20% of the mass of the sand sample, and uniformly mixing to obtain a sand material; Step 4: adding calcium sugar in an amount of 3-8% of the mass of the sand sample to the sand material obtained in step 3, and uniformly mixing to obtain a calcium sugar-sand material; Step 5: compacting the calcium sugar-sand material obtained in step 4 in 2-4 layers, with a compacting height of 20-40 mm for each layer, and scraping the layers to treat the layers, and then placing and curing at 35-40°C for 5-7 days; Step 6: spraying a locust bean gum solution in an amount of 7-25% of the mass of the sand sample on the surface of the calcium sugar-sand material obtained after standing and curing in step 5, and placing and curing at 35-40°C for 24-36 h to obtain a solidified sand body.

2. The method for preventing surface sliding and erosion of sandy soil slope according to claim 1, characterized in that, The preparation method of the cementing solution in step 2 is: Urea solution and anhydrous calcium chloride solution are uniformly mixed in equal concentration and equal volume to obtain a cementing solution with a concentration of 0.5-2 mol / L.

3. The method for preventing surface sliding and erosion of sandy soil slope according to claim 1, characterized in that: The preparation method of the locust bean gum solution in step 6 is: Locust bean gum and deionized water are uniformly mixed in a mass ratio of 1:(100-200).

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