Ecological remediation method for engineering muck landfill based on double-layer soil structure

Abstract

The invention discloses a double-layer soil structure-based engineering residue soil filling body ecological improvement method, which comprises the following steps: S1, preparing a surface soil layer soil material: selecting sandy loam soil or clay loam soil in engineering residue soil as a surface soil main body, adding bagasse into the surface soil main body, and mixing the surface soil main body with the bagasse to obtain the surface soil layer soil material; s2, preparing a subsoil layer soil material: selecting clay loam soil in engineering residue soil as a subsoil main body, adding xanthan gum into the subsoil main body, and mixing the subsoil main body with the xanthan gum to obtain the subsoil layer soil material; s3, the subsoil layer soil material is laid on the surface of the engineering muck filling body to form a subsoil layer structure; s4, the subsoil layer is subjected to compaction treatment; and S5, the surface soil layer soil material is laid on the surface of the subsoil layer to obtain a surface soil layer structure. The problems of water and soil loss and ecological function deficiency of the engineering muck landfill can be effectively solved through a synergistic mechanism of coupling plant root system soil fixation, bagasse water retention reinforcement and xanthan gum impermeability.

Description

Technical Field

[0001] The present invention relates to the technical field of geotechnical engineering and ecological restoration, and in particular to an ecological restoration method for an engineering slag landfill based on a double-layer soil structure. Background Art

[0002] Construction waste soil generally includes sandy loam, clay loam, silt, mixed waste soil, etc., among which sandy loam accounts for 30%-50%, clay loam accounts for 20%-35%, and sandy loam and clay loam together account for more than half of the construction waste soil.

[0003] For the construction waste landfill formed by construction waste filling, due to its poor soil solidification and anti-seepage ability and weak ecological function, the construction waste landfill is not suitable for plant planting, which is not conducive to ecological restoration.

[0004] In view of the particularity of construction waste landfills and to meet the development needs of ecological restoration, it is necessary to propose ecological remediation methods for construction waste landfills. Summary of the Invention

[0005] The purpose of the present invention is to provide an ecological remediation method for engineering waste landfills based on a double-layer soil structure in response to the deficiencies of the existing technology. The ecological remediation method for engineering waste landfills based on a double-layer soil structure is based on a double-layer soil structure composed of a topsoil layer structure and a subsoil layer structure. The topsoil layer structure serves as an ecological planting layer and the subsoil layer structure serves as an anti-seepage layer. Since bagasse is incorporated into the topsoil layer structure and xanthan gum is incorporated into the subsoil layer structure, the topsoil layer structure can achieve the triple functions of water retention, fertilization, and root reinforcement, and the subsoil layer structure can significantly reduce the permeability coefficient and achieve seepage control and soil and water conservation. Therefore, the present invention can effectively solve the problems of soil erosion and lack of ecological functions in engineering waste landfills by coupling the synergistic mechanism of plant root consolidation, bagasse water retention and reinforcement, and xanthan gum anti-seepage.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions.

[0007] A method for ecological remediation of an engineering waste landfill based on a double-layer soil structure includes the following steps, specifically:

[0008] Step S1, preparing topsoil material: selecting sandy loam or clay loam from construction waste soil as the main body of topsoil, adding bagasse to the main body of topsoil, and mixing the main body of topsoil and bagasse to obtain the topsoil material;

[0009] Step S2, preparing a subsoil material: selecting clay loam from construction waste as the main body of the subsoil, adding xanthan gum to the main body of the subsoil, and mixing the main body of the subsoil with the xanthan gum to obtain the subsoil material;

[0010] Step S3: laying the subsoil material on the surface of the construction waste landfill, thereby forming a subsoil structure on the surface of the construction waste landfill;

[0011] Step S4, compacting the subsoil layer;

[0012] Step S5: laying the topsoil material on the surface of the subsoil layer to obtain the topsoil structure.

[0013] Wherein, in the step S1, the amount of bagasse added is 0.1% or 0.3% or 0.5% of the mass of the main body of the topsoil.

[0014] Among them, sugarcane bagasse has a porous fiber structure, the fiber length of sugarcane bagasse is 0.65mm-2.17mm, and the width of sugarcane bagasse is 21μm-28μm.

[0015] Wherein, in said step S2, the amount of xanthan gum added is 0.1% or 0.3% or 0.5% of the mass of the main body of the heart soil.

[0016] Wherein, in said step S4, the thickness of the subsoil layer structure after compaction treatment is 25 cm;

[0017] In step S5, the thickness of the topsoil layer structure is 25 cm.

[0018] Compared with the prior art, the present invention has the following beneficial effects, specifically:

[0019] 1. The topsoil layer is made of sandy loam or clay loam from construction waste soil, mixed with bagasse. The topsoil layer serves as an ecological planting layer. By incorporating bagasse, the ecological planting layer can achieve the triple functions of water retention, fertilization, and root reinforcement, and can effectively enhance soil stability by collaborating with plant roots.

[0020] 2. The subsoil layer is constructed from clay loam from construction waste, mixed with xanthan gum. The subsoil layer serves as an anti-seepage layer. Because xanthan gum can form a highly viscous pseudoplastic solution, it effectively blocks soil pores, binds moisture, and bridges soil particles. This means the subsoil layer significantly reduces permeability and achieves seepage control and soil and water conservation.

[0021] 3. The present invention can effectively solve the problems of soil erosion and ecological function loss in engineering waste landfills by coupling the synergistic mechanism of plant root consolidation, bagasse water retention and reinforcement, and xanthan gum anti-seepage.

[0022] 4. The present invention uses waste soil and industrial by-products (bagasse, xanthan gum) as resource materials, that is, the present invention has the advantages of being green and low-cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be further described below with reference to the accompanying drawings. However, the embodiments in the accompanying drawings do not constitute any limitation to the present invention.

[0024] Figure 1 This is a comparison chart of the average germination rate of ryegrass plants.

[0025] Figure 2 This is a comparison chart of the plant height of ryegrass plants.

[0026] Figure 3 This is a comparison chart of the results of the variable head permeability test on the surface soil structure.

[0027] Figure 4 This is a comparison chart of the results of the variable head permeability test of the subsoil structure.

[0028] Figure 5 This is a diagram of the test process of the topsoil structure collapse in Group A.

[0029] Figure 6 This is a diagram of the structural collapse test process of the topsoil layer in Group C.

[0030] Figure 7 A comparison chart of the amount of topsoil structure collapse in groups A and C.

[0031] Figure 8 This is a diagram of the process of the core soil layer structure collapse test in Group A.

[0032] Figure 9 This is a diagram of the process of the core soil layer structure collapse test in Group C.

[0033] Figure 10 A comparison chart of the structural collapse of the core soil layers of groups A and C. DETAILED DESCRIPTION

[0034] The present invention will be described below with reference to specific embodiments.

[0035] A method for ecological remediation of an engineering waste landfill based on a double-layer soil structure includes the following steps, specifically:

[0036] Step S1, preparing topsoil material: selecting sandy loam or clay loam from construction waste soil as the main body of topsoil, adding bagasse to the main body of topsoil, and mixing the main body of topsoil and bagasse to obtain the topsoil material;

[0037] Step S2, preparing a subsoil material: selecting clay loam from construction waste as the main body of the subsoil, adding xanthan gum to the main body of the subsoil, and mixing the main body of the subsoil with the xanthan gum to obtain the subsoil material;

[0038] Step S3: laying the subsoil material on the surface of the construction waste landfill, thereby forming a subsoil structure on the surface of the construction waste landfill;

[0039] Step S4, compacting the subsoil layer;

[0040] Step S5: laying the topsoil material on the surface of the subsoil layer to obtain the topsoil structure.

[0041] Specifically, in step S1, the amount of bagasse added is 0.1% or 0.3% or 0.5% of the mass of the topsoil. The bagasse has a porous fiber structure, a fiber length of 0.65 mm to 2.17 mm, and a width of 21 μm to 28 μm.

[0042] In addition, in step S2, the amount of xanthan gum added is 0.1% or 0.3% or 0.5% of the mass of the core soil.

[0043] In addition, in the step S4, the thickness of the subsoil layer structure after compaction is 25 cm; in the step S5, the thickness of the topsoil layer structure is 25 cm.

[0044] Based on the above steps, the method for ecological remediation of engineering waste landfills based on a double-layer soil structure of the present invention has the following advantages, specifically:

[0045] 1. The topsoil layer is made of sandy loam or clay loam from construction waste soil, mixed with bagasse. The topsoil layer serves as an ecological planting layer. By incorporating bagasse, the ecological planting layer can achieve the triple functions of water retention, fertilization, and root reinforcement, and can effectively enhance soil stability by collaborating with plant roots.

[0046] 2. The subsoil layer is constructed from clay loam from construction waste, mixed with xanthan gum. The subsoil layer serves as an anti-seepage layer. Because xanthan gum can form a highly viscous pseudoplastic solution, it effectively blocks soil pores, binds moisture, and bridges soil particles. This means the subsoil layer significantly reduces permeability and achieves seepage control and soil and water conservation.

[0047] 3. The present invention can effectively solve the problems of soil erosion and ecological function loss in engineering waste landfills by coupling the synergistic mechanism of plant root consolidation, bagasse water retention and reinforcement, and xanthan gum anti-seepage.

[0048] 4. The present invention uses waste slag and industrial by-products (bagasse, xanthan gum) as resource materials, that is, the present invention has the advantages of being green and low-cost, and can provide a replicable solution for soil consolidation, anti-seepage and ecological restoration of engineering slag yards.

[0049] The following is an exploration of the ecological, impermeability and soil-fixing properties of the double-layer soil structure consisting of a topsoil layer structure and a subsoil layer structure through plant planting tests, variable water head permeability tests and disintegration tests. Specifically:

[0050] a. Set up experimental and control groups: the incorporation amount of bagasse in the topsoil layer is 0.1%, 0.3%, and 0.5%, and the incorporation amount of xanthan gum in the subsoil layer is 1%, 3%, and 5%. The main type of topsoil in the topsoil layer is sandy loam or clay loam. That is, there are 3×3×2=18 experimental groups in total. The specific information of the experimental and control groups is as follows:

[0051]

[0052]

[0053] b. Select ryegrass as the plant to be planted, set the growth cycle to six weeks, and observe the average germination rate of ryegrass plants after six weeks (e.g. Figure 1 as shown) and plant height (as shown) Figure 2 shown);

[0054] Based on the average germination rate and plant height of ryegrass plants, six optimal working conditions, A, C, G, I, N, and O, were selected. These six working conditions have good ecological properties, indicating that compared with clay loam, using sandy loam as the main surface soil structure is more conducive to plant growth.

[0055] c. Carry out variable water head permeability test on the surface soil structure. The test results are as follows: Figure 3 As shown, the T group is a topsoil structure of pure sandy loam, the U group is a topsoil structure of pure sandy loam + 0.1% (incorporated amount) sugarcane bagasse, and the V group is a topsoil structure of pure sandy loam + 0.3% (incorporated amount) sugarcane bagasse;

[0056] According to the experimental results, the anti-permeability of group A, group C and group N is stronger;

[0057] d. Carry out variable water head permeability test on the subsoil structure. The test results are shown in the following table and Figure 4 As shown;

[0058] The X group and the Y group were set up, wherein the X group was the subsoil structure containing only clay loam, and the Y group was the subsoil structure containing clay loam + 1% (doped amount) xanthan gum;

[0059] Among them, the A and C working conditions have the best impermeability compared with other working conditions and the control group. Among them, the impermeability of Y is much better than that of X, which shows that the addition of xanthan gum has greatly improved the impermeability of the soil. However, the impermeability of A and C working conditions is worse than that of Y, which shows that the roots in the soil will affect the impermeability of the soil, making its impermeability weakened. However, it is still stronger than X and S, which shows that the superiority of xanthan gum admixture can weaken the influence of roots on the impermeability of the soil.

[0060] The impermeability of A and C is of the same order of magnitude, and the impermeability of C is slightly stronger than that of A;

[0061]

[0062]

[0063] e. Further measure the soil-fixing properties of Group A and Group C based on the disintegration test. Figures 5 to 10 As shown;

[0064] Specifically, such as Figures 5 to 7 As shown, the topsoil structure in Group A disintegrated faster, with most of it disintegrating within 30 minutes. Compared to Group A, the topsoil structure in Group C disintegrated more slowly, not disintegrating until 3 hours. Therefore, it can be concluded that the topsoil structure in Group C (with 0.3% bagasse incorporation) exhibited better soil-consolidation properties than that in Group A. The coupling effect of 0.3% bagasse incorporation with the root-soil complex provided the best soil-consolidation performance.

[0065] In addition, if Figures 8 to 10 As shown, the disintegration rates of the core soil structures of Groups A and C were both slow, but the general trend slope of Group C was gentler than that of Group A, indicating a slower disintegration rate. Furthermore, within the same timeframe, the amount of disintegration in Group C was smaller than that in Group A. Therefore, the core soil structure of Group C had a stronger ability to resist disintegration, maintained stability in water for a longer period, and exhibited stronger soil consolidation properties. Therefore, the disintegration experiment revealed that the core soil structure of Group A disintegrated faster from the beginning to the end than the core soil structure of Group C, and exhibited a larger amount of disintegration. Therefore, it can be concluded that the core soil structure of Group C exhibited better soil consolidation properties than the core soil structure of Group A.

[0066] In summary, after plant planting tests, variable head permeability tests, and disintegration tests, Group C (sandy loam in the topsoil layer, 0.3% bagasse mixed in the topsoil layer, and 1% xanthan gum mixed in the subsoil layer) has the best ecology, impermeability, and soil-fixing properties, which can provide reference and reference for soil fixation, impermeability, and ecological restoration of subsequent engineering slag dumps.

[0067] The above contents are only preferred embodiments of the present invention. For ordinary technicians in this field, according to the concept of the present invention, there may be changes in the specific implementation methods and application scopes. The contents of this specification should not be understood as limiting the present invention.

Claims

1. A method for ecological remediation of engineering waste landfill based on a double-layer soil structure, characterized in that: The following steps are included, specifically: Step S1, preparing topsoil material: selecting sandy loam or clay loam from construction waste soil as the main body of topsoil, adding bagasse to the main body of topsoil, and mixing the main body of topsoil and bagasse to obtain the topsoil material; Step S2, preparing a subsoil material: selecting clay loam from construction waste as the main body of the subsoil, adding xanthan gum to the main body of the subsoil, and mixing the main body of the subsoil with the xanthan gum to obtain the subsoil material; Step S3: laying the subsoil material on the surface of the construction waste landfill, thereby forming a subsoil structure on the surface of the construction waste landfill; Step S4, compacting the subsoil layer; Step S5: laying the topsoil material on the surface of the subsoil layer to obtain the topsoil structure.

2. The method for ecological remediation of a construction waste landfill based on a double-layer soil structure according to claim 1, characterized in that: In step S1, the amount of bagasse added is 0.1% or 0.3% or 0.5% of the mass of the topsoil.

3. The method for ecological remediation of an engineering waste landfill based on a double-layer soil structure according to claim 1, characterized in that: Bagasse has a porous fiber structure, the fiber length of bagasse is 0.65mm-2.17mm, and the width of bagasse is 21μm-28μm.

4. The method for ecological remediation of a construction waste landfill based on a double-layer soil structure according to claim 1, characterized in that: In step S2, the amount of xanthan gum added is 0.1% or 0.3% or 0.5% of the mass of the core soil.

5. The method for ecological remediation of an engineering waste landfill based on a double-layer soil structure according to claim 1, characterized in that: In step S4, the thickness of the subsoil structure after compaction is 25 cm; In step S5, the thickness of the topsoil layer structure is 25 cm.

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