A screening construction method of soil for slope ecological restoration

Abstract

The application discloses a screening construction method for soil for slope ecological restoration, and is suitable for separation of gravel particles and mud components in moist engineering soil required by spray seeding construction. The method realizes soil and stone separation by means of water mixing, mechanical stirring, standing and settling, upper mud transfer and screen filtering of a mud separation tank, does not need special wet screening equipment, is simple in construction and strong in adaptability, can effectively reduce the risk of blockage of a spray seeding machine pipeline and a nozzle, and improves the continuity and stability of spray seeding construction.

Description

Technical Field

[0001] This invention relates to the field of slope ecological restoration and hydroseeding construction technology, specifically to a method for screening soil for slope ecological restoration, and more particularly to a method for screening soil for damp engineering projects that requires separation of gravel particles to meet the requirements of hydroseeding construction. The method is applicable to damp engineering soil, especially clay and silt with high moisture content, strong cohesion, and a tendency to clump. Background Technology

[0002] In engineering scenarios such as mine restoration, roadside slope revegetation, ecological restoration of exposed slopes, and geological disaster management, hydroseeding is often used to uniformly spray a hydroseeding slurry containing engineering soil, planting substrate, fertilizer, water-retaining agent, binder, fiber material, and plant seeds onto the slope surface, thereby forming a cover layer that retains water and fertilizer and provides conditions for subsequent plant growth. The hydroseeding construction usually relies on a hydroseeding machine to complete the mixing, transportation, and spraying of the slurry. Therefore, the quality of the engineering soil entering the hydroseeding machine will directly affect the continuity of the hydroseeding operation and the construction effect.

[0003] In current slope revegetation construction, the soil used in hydroseeding machines is mostly sourced from on-site extraction, stockpiling, or external transportation. Due to the complex actual construction environment, this type of soil usually has a certain moisture content and is often mixed with stones, gravel, and other larger particles. Especially after rain, on mountain slopes, or when the original soil itself has a high moisture content, the soil is prone to being damp, sticky, or even clumped. This is particularly true for clay and silt, which, due to their high fine particle content, large specific surface area, and strong adhesion and plasticity upon contact with water, are more likely to form aggregates that encapsulate stones. If this damp soil is directly fed into the hydroseeding machine without effective treatment, the larger stones mixed in can easily enter the hydroseeding machine's conveying system, causing blockages in the conveying pipelines and nozzles during pumping and spraying, thus affecting the continuity of spraying, construction efficiency, and uniformity of coverage.

[0004] To address the aforementioned engineering problems, existing technologies typically employ sieves to screen soil materials. For relatively dry and loose soil, sieves can, to some extent, intercept large-diameter stones, thus achieving the basic screening purpose. However, for damp engineering soil, especially damp clay and silt, the high water content and strong adhesion of the soil, coupled with the presence of mud layers on the stone surface and the tendency of the soil to form mud clumps, easily lead to problems such as sieve hole blockage, low screening efficiency, and difficulty in effectively separating stones during direct screening, resulting in waste of construction materials. In other words, sieves are not entirely unusable for damp engineering soil, but it is difficult to directly and efficiently screen raw damp soil, especially damp clay and silt, in a continuous and stable manner.

[0005] In addition, some existing technologies also use wet screening equipment, vibrating screening equipment or soil separation equipment to treat moist soil materials. However, such equipment is usually more complex in structure, more expensive, and requires more construction preparation work. Furthermore, in slope restoration projects, there are problems such as inconvenient equipment layout, insufficient on-site adaptability, and relatively cumbersome operation procedures, which are not conducive to the rapid organization and implementation of construction on site.

[0006] Therefore, there is an urgent need to propose a screening method suitable for damp engineering soil, especially damp clay and silt, so that the stones in the damp engineering soil can be separated in the first stage by sedimentation in the mud separation tank, and then the upper mud layer can be transferred and separated in the second stage by screen. This solves the problem that damp engineering soil is difficult to screen effectively by direct screening, while retaining the effective filtering function of screen for thinner mud, so as to meet the requirements of hydroseeding construction for the particle size and flowability of engineering soil. Summary of the Invention

[0007] In view of this, the present invention provides a screening construction method for soil used in slope ecological restoration, in order to solve the technical problems in the prior art that wet engineering soil, especially wet clay and silt, is difficult to be effectively screened directly through a screen due to its high water content, strong adhesion and easy agglomeration. In addition, large-diameter stones mixed in wet engineering soil are easy to enter the hydroseeding machine conveying system with the soil and cause blockage of the conveying pipeline and nozzle, thereby affecting the continuity of hydroseeding and construction efficiency.

[0008] In particular, this invention relates to a method for screening and applying soil for damp engineering projects, requiring the separation of gravel particles to meet the requirements of hydroseeding. The method is applicable to damp engineering soils, especially clay and silt with high moisture content, strong cohesion, and a tendency to clump.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] This invention first discloses a screening construction method for soil used in slope ecological restoration. This method is suitable for separating gravel particles and mud components in moist engineering soil required for hydroseeding, thereby reducing the possibility of large-diameter gravel entering the hydroseeding machine's conveying system and causing blockages in the conveying pipeline and nozzles. The method achieves the separation of soil components and gravel components in moist engineering soil through water mixing, mechanical stirring, static settling, upper mud transfer, and sieve filtration in a mud separation tank. Specifically, it includes the following steps:

[0011] S1. The damp engineering soil mixed with stones is put into the mud separation tank. The damp engineering soil is soil containing a certain amount of moisture and mixed with stone particles.

[0012] S2. Add water to the mud separation tank to improve the dispersion and fluidity of the wet engineering soil in the tank, so that it can form a thinner mud system.

[0013] S3. Use machinery to stir the wet engineering soil and water in the mud separation tank, so that the wet engineering soil and water are fully mixed to form mud, and the soil attached to the surface of the stones is removed, so as to reduce the adhesion between the stones and the soil.

[0014] S4. After stopping stirring, allow the mixture to settle. Utilize the density difference and settling velocity difference between the stones and the mud to allow the stones to gradually settle to the bottom of the mud separation tank under the action of gravity, forming a stone sedimentation layer. The mud is on the upper layer, thus achieving soil-stone stratification.

[0015] S5. Transfer the upper layer of mud from the mud separation tank out of the tank;

[0016] S6. The upper layer of mud is screened and filtered through a screen to separate the residual stone particles and obtain mud suitable for hydroseeding construction.

[0017] S7. Transfer the slurry filtered through the screen to the hydroseeding machine for slope hydroseeding construction;

[0018] S8. Clean and centrally process the stones deposited at the bottom of the mud separation tank and the stones obtained by sieving, so that the mud separation tank can enter the next round of separation operation of wet engineering soil.

[0019] Furthermore, the damp engineering soil mentioned in step S1 is an engineering soil with high moisture content, strong adhesion and easy clumping, preferably silt, clay, or mixed soil with more fine particles.

[0020] Furthermore, when the soil used in the project is silt, its natural moisture content is 12% to 25%, preferably 15% to 20%; when the soil used in the project is clay, its natural moisture content is higher than the plastic limit and is in a plastic to soft plastic state, preferably with a liquid index IL of 0.25 to 0.75.

[0021] Furthermore, the clay, based on common engineering clay, has a natural moisture content of 20% to 30%.

[0022] Furthermore, the gravel mixed in the damp engineering soil described in step S1 includes gravel with a particle size greater than 2.5 cm.

[0023] Furthermore, the mud separation tank mentioned in step S1 is a cast-in-place tank, a prefabricated tank, a steel plate tank, or a tank structure formed by excavation and provided with an anti-seepage layer. The mud separation tank is used to contain moist engineering soil, water, and mud formed by stirring, and provides working space for subsequent static settling and stratified slurry extraction.

[0024] Furthermore, the feeding described in step S1 and the mud transfer described in step S5 are accomplished by one or more of the following equipment: excavator, loader, grab bucket, slurry pump, and mud pump, to adapt to the requirements of feeding, transporting, and mud extraction operations under different construction site conditions.

[0025] Furthermore, the water added in step S2 is clean water, recycled water, or a mixture of clean water and recycled water. The recycled water is reclaimed water that has been settled or treated to meet the requirements for soil separation and hydroseeding in wet engineering projects.

[0026] Furthermore, the mixing described in step S3 is carried out by excavator bucket turning, mechanical mixing device agitation, or a combination thereof, so as to break down the mud clumps in the wet engineering soil, disperse the soil particles in the water, and form a relatively uniform slurry.

[0027] Furthermore, in step S5, when transferring the mud, the mud collection point is located below the liquid surface of the mud separation tank and maintains a predetermined distance from the bottom stone sedimentation layer to reduce disturbance to the bottom stone sedimentation layer during mud collection. The predetermined distance is 50-70 cm.

[0028] Furthermore, the screen mentioned in step S6 is a filter screen suitable for intercepting stone particles, and the upper mud slurry treated in steps S2 to S5 has improved fluidity and reduced adhesion.

[0029] Furthermore, the mud slurry transferred to the hydroseeding machine in step S7 is mixed with one or more of the planting substrate, fertilizer, water-retaining agent, binder, fiber material and plant seeds required for hydroseeding construction, and then hydroseeded on the slope to form a hydroseeding slurry that meets the requirements of slope ecological restoration construction.

[0030] Compared with the prior art, the significant advantages of this invention are:

[0031] First, by adding water, mixing mechanically, and allowing the soil to settle in the mud separation tank, the stones mixed in with the damp engineering soil settle before entering the screen to form a stone sedimentation layer, thus solving the problem that damp engineering soil, especially damp clay and silt, is difficult to directly screen through the screen for effective separation.

[0032] Secondly, the pre-treated upper layer of mud has improved fluidity and reduced adhesion. Then, the residual stones are further separated by a screen, thus achieving a graded screening effect that combines sedimentation separation and screen separation.

[0033] Third, it does not rely on complex specialized wet screening equipment. The required equipment mainly consists of commonly used machinery on the construction site, mud separation tanks, and screens. The construction organization is relatively simple and the site adaptability is strong.

[0034] Fourth, it can effectively reduce the probability of large-diameter stones entering the hydroseeding machine's conveying system, thereby reducing the incidence of blockages in the hydroseeding machine's conveying pipelines and nozzles, and improving the continuity and operational stability of slope revegetation hydroseeding construction. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of the construction method described in this invention.

[0037] Figure 2 This is an actual on-site construction drawing of the construction method described in this invention. Detailed Implementation

[0038] The present invention will now be described in detail with reference to specific embodiments. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0039] Example 1

[0040] A method for screening and constructing soil for slope ecological restoration

[0041] At slope ecological restoration or hydroseeding construction sites, the soil used by hydroseeding machines is usually sourced locally from the construction area, from stockpiles, or transported from elsewhere. Because this type of soil often has a certain moisture content and contains larger particles such as stones and gravel, especially when it contains large stones, if it is directly fed into the hydroseeding machine without proper treatment, it can easily cause blockages in the delivery pipelines and nozzles during pumping and spraying, affecting continuous construction and spraying quality.

[0042] This invention is particularly suitable for damp engineering soil, especially clay and silt. Clay and silt, due to their high proportion of fine particles, strong water absorption, and tendency to exhibit strong adhesion and plasticity upon contact with water, tend to form mud clumps that encapsulate stones when wet, making it difficult to effectively separate the stones from the raw soil using conventional direct sieving methods. Therefore, this invention employs a combined treatment method of "slurry separation tank sedimentation pre-separation + further separation by sieving" to improve the screening effect.

[0043] In practice, a mud separation tank is first set up. The mud separation tank can be a cast-in-place tank, a prefabricated tank, a steel plate tank, or a tank structure excavated on site with an impermeable layer, depending on the site construction conditions. The volume of the mud separation tank can be set according to the scale of the hydroseeding construction, the amount of soil to be treated at one time, and the conditions of mechanical operation, so as to meet the requirements of feeding, mixing, settling, slurry collection, and subsequent screen filtration. The mud separation tank is used to hold the wet engineering soil, water, and mud formed by mixing, and provides working space for subsequent static settling and stratified slurry collection.

[0044] In the specific operation process, the damp engineering soil mixed with stones is first put into the mud separation tank. The damp engineering soil is soil containing a certain amount of moisture and mixed with stone particles. The feeding can be carried out by mechanical equipment such as excavators, loaders, and grab buckets. Depending on the soil conditions at the construction site, the stones mixed in the damp engineering soil may include stones with a particle size greater than 2.5cm. These stones are more likely to cause blockage of the hydroseeding machine's conveying system during hydroseeding construction, so they need to be separated first.

[0045] Water is then added to the mud separation tank. The added water can be clean water, recycled water, or a mixture of clean water and recycled water. The recycled water is recycled water that has been settled or treated to meet the requirements for separating and spraying wet engineering soil. The purpose of adding water is to improve the dispersion of wet engineering soil in the tank, enhance the dispersibility and fluidity of soil particles in the liquid phase, and create conditions for subsequent mixing to form a thinner mud. For engineering soil with low moisture content or high soil cohesion, the amount of water added can be appropriately increased; for soil with high moisture content, the amount of water added can be reduced accordingly, so that the resulting upper mud layer has good fluidity and is easy to filter through a screen.

[0046] The wet engineering soil and water in the mud separation tank are stirred mechanically to fully mix the soil and water to form mud, and to remove the soil adhering to the surface of the stones, thereby reducing the adhesion between the stones and the soil. The stirring can be carried out by excavator bucket turning, mechanical stirring device agitation, or a combination thereof. Through mechanical stirring, the mud clumps in the wet engineering soil gradually disintegrate, and the soil particles disperse in the water to form a relatively uniform mud, thus providing conditions for subsequent soil-rock stratification using settlement difference.

[0047] After mixing, the mixture is allowed to settle. Due to the density and settling velocity differences between the stones and the mud, the stones gradually settle to the bottom of the mud separation tank under gravity, forming a stone sedimentation layer, while the mud is on the upper layer, thus achieving soil-stone stratification. If necessary, the settling time can be adjusted according to the soil moisture content, stone content, and on-site operation rhythm to make the stratification state in the tank more stable.

[0048] After the stratification is formed, the upper layer of mud in the mud separation tank is transferred out of the tank. The mud transfer can be completed by one or more of the following equipment: excavator, loader, grab bucket, suction pump, mud pump, etc., to adapt to the requirements of feeding, transportation and mud sampling operations under different construction site conditions. In order to reduce the disturbance to the stone sediment layer at the bottom of the tank during the mud sampling process, preferably, the mud sampling position is located below the liquid surface of the mud separation tank and maintains a predetermined distance from the stone sediment layer at the bottom of the tank. The upper layer of mud transferred out here is used as the object for subsequent screen filtration.

[0049] The upper layer of mud is screened and filtered through a sieve to separate residual stone particles, resulting in mud suitable for hydroseeding. The sieve is a filter sieve suitable for intercepting stone particles. After the above steps, the upper layer of mud has increased fluidity and reduced adhesion, so the sieve can effectively filter the residual stones. Here, the sieve is not used directly to screen the original damp engineering soil, but to further separate the upper layer of mud after pretreatment in the mud separation tank.

[0050] The slurry filtered through a screen is transferred to a hydroseeding machine for slope hydroseeding construction. The slurry transferred to the hydroseeding machine can be mixed with one or more of the planting substrate, fertilizer, water-retaining agent, binder, fiber material and plant seeds required for hydroseeding construction before slope hydroseeding to form a hydroseeding slurry that meets the requirements of slope ecological restoration construction.

[0051] The stones deposited at the bottom of the mud separation tank, as well as the stones filtered through the screen, are cleaned and centrally processed so that the mud separation tank can proceed to the next round of separation of wet engineering soil. The stone cleaning can be completed by mechanical equipment such as excavators and loaders or by manual assistance. After cleaning, the mud separation tank and screen device can continue to be used for the processing of the next batch of wet engineering soil, thus forming a cyclical operation mode suitable for continuous on-site construction.

[0052] The core of this invention lies not in eliminating the screen, but in changing the stage of its use. For original damp engineering soil, especially damp clay and silt, due to its high water content, strong adhesion and easy agglomeration characteristics, the screen is difficult to work effectively directly. However, by adding water, mixing mechanically, and allowing static sedimentation in the mud separation tank, the stones first settle to form a stone sedimentation layer, and then the thinner upper mud layer is filtered through the screen. This allows the screen to function in a more suitable material state, thereby achieving a graded screening effect that combines sedimentation separation and screen separation.

[0053] Compared with the traditional direct sieving method, the present invention is more suitable for the pretreatment of damp engineering soil in the construction site of slope revegetation spraying, especially for the treatment of damp clay and silt. Compared with the solution that relies entirely on special wet screening equipment, the equipment required by the present invention is mainly common machinery used on construction site, mud separation tank and screen. The equipment structure is relatively simple, the construction organization is more flexible, and the site adaptability is strong.

[0054] The method of this invention can effectively reduce the possibility of large-diameter stones entering the hydroseeding machine's conveying system, reduce the incidence of blockages in the hydroseeding machine's conveying pipelines and nozzles, improve the continuity and operational stability of slope revegetation hydroseeding construction, and help improve hydroseeding construction efficiency and material utilization.

[0055] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various variations or substitutions within the technical scope disclosed in the present invention, and these should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of protection of the claims.

Claims

1. A method for screening and constructing soil for slope ecological restoration, comprising: S1. The damp engineering soil mixed with stones is put into the mud separation tank, water is added and stirred, and then it is allowed to settle to achieve soil-stone stratification. The bottom is the stone sedimentation layer and the top is the mud layer. S2. The mud layer is transferred out of the mud separation tank. The obtained mud is screened and filtered, and the filtered mud is collected for slope spraying construction.

2. The screening construction method according to claim 1, wherein: The damp engineering soil mentioned in step S1 is engineering soil with high water content, strong adhesion and easy clumping, and is mixed with stones with a particle size greater than 2.5cm.

3. The screening construction method according to claim 2, wherein: The soil used in the damp engineering project is engineering soil with high moisture content, strong cohesion, and easy clumping.

4. The screening construction method according to claim 3, wherein: The soil used in the project is silt, clay, or mixed soil with a high content of fine particles.

5. The screening construction method according to claim 4, wherein: When the soil used in the project is silty soil, its natural moisture content is 12% to 25%, preferably 15% to 20%; When the soil used in the project is clay, its natural water content is higher than the plastic limit and it is in a plastic to soft plastic state, preferably with a liquid index IL of 0.25 to 0.

75.

6. The screening construction method according to claim 5, wherein: When the soil used in the project is silty soil, its natural moisture content is 15% to 20%; When the soil used in the project is clay, its natural water content and liquidity index (IL) are 0.25 to 0.

75.

7. The screening construction method according to claim 6, wherein: The clay, based on common engineering clay, has a natural moisture content of 20% to 30%.

8. The screening construction method according to claim 1, wherein: The mud separation tank mentioned in step S2 is selected from: cast-in-place tank, prefabricated tank, steel plate tank, or tank structure formed by excavation and equipped with an anti-seepage layer.

9. The screening construction method according to claim 1, wherein: The sieve used in step S2 is a filter sieve suitable for intercepting stone particles.

10. The screening construction method according to claim 1, wherein: When collecting the filtered mud in step S2, the mud collection point is located below the liquid surface of the mud separation tank and at a predetermined distance of 50-70 cm from the bottom stone sedimentation layer to reduce disturbance to the bottom stone sedimentation layer during the mud collection process.

11. The screening construction method according to claim 1, wherein: The filtered mud used for slope spraying construction in step S2 needs to be mixed with one or more of the following materials required for spraying construction: planting substrate, fertilizer, water-retaining agent, binder, fiber material and plant seeds, before being sprayed on the slope.

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