CN113396795B - Foreign soil and soil layer structure based on river and lake bottom mud and phosphorite solid waste and preparation method - Google Patents

Abstract

The invention provides a foreign soil layer structure based on river and lake bottom mud and phosphorite solid waste and a preparation method thereof. The soil layer structures are sequentially a foreign soil surface layer, a middle permeable layer and a foreign soil base layer from top to bottom, and the contact surface between each layer of foreign soil layer structure is a zigzag transition structure; the invention utilizes the industrial solid wastes such as phosphorus slag, phosphogypsum, steel slag and the like to modify and improve the dredging bottom mud of rivers and lakes to be used as the vegetation concrete alien soil, the acidity and alkalinity of the alien soil meet the growth requirement of vegetation and can provide continuous nutrition supply for the vegetation, the invention has the technical advantages of easy obtainment of raw materials, simple process, excellent economy, ecological environmental protection and the like, can also effectively solve the technical problems of high cost of the vegetation concrete alien soil, secondary pollution of solid waste piles to the environment and the like at the present stage, and is particularly suitable for urban areas with the requirements of river and lake remediation and industrial solid waste disposal.

Description

Foreign soil and soil layer structure based on river and lake bottom mud and phosphorite solid waste and preparation method

Technical Field

The invention relates to the technical field of solid waste treatment and urban soil improvement, and particularly provides a foreign soil layer structure based on solid waste of river and lake bottom mud and phosphorite and a preparation method thereof.

Background

Aiming at the current situations of serious water and soil loss and reduced ecological function of the bank slope in China, the development and popularization of the ecological bank protection technology becomes an important technical measure for the treatment and restoration of the river and lake ecological system in China. The vegetation concrete is an ecological slope bank protection technology which is widely applied, can be used for restoring and reconstructing ecological environments such as river bank protection, channel revetment, highway side slope and the like, has the characteristic of reinforcing the bank by the traditional concrete bank protection, can form green natural landscape, keeps the biological diversity of nearby microbial habitats and plays a role in purifying water quality, and has very outstanding social benefit and ecological benefit.

The foreign soil paved on the surface of the plant-growing concrete provides a growing environment for plants and protects the plant-growing concrete filling material from loss. The alien soil is usually prepared by using common soil as a base material and then mixing with proper nutrient fertilizer and/or organic matters, adhesive, water-retaining agent and the like. At present, the research on foreign soil in China mainly focuses on the aspects of construction devices and processes. The utility model discloses a Chinese utility model with publication number CN201120312772.0 discloses a soil removal fixing device, which comprises a soil removal bag which is parallel leaned on a base surface and an anchoring nail for fixing the soil removal bag; the Chinese invention patent with publication number CN101103696B discloses a method for recovering vegetation on a rock slope, which adopts a combination mode of double-layer spraying of foreign soil and organic matter and direct seeding of seeds and transplanting of arbor and shrub seedlings; the Chinese patent with publication number CN105340661B discloses a block-shaped foreign soil planting layer and a method for planting trees by using the same, aiming at saline-alkali areas, the method consists of an upper layer of aeolian pulverized fine sand soil layer, a lower layer of large particle layer and a grid cloth positioned between the upper layer and the lower layer, and can effectively control the salt content in the soil and avoid the invasion of the surrounding salt content.

In the aspects of foreign soil property improvement and structure research, the Chinese patent with publication number CN101796913B discloses foreign soil for slope protection of loess slope plants, which meets the physical structure and nutritional ingredients required by the growth of the slope plants in semiarid loess regions by adding a certain proportion of soil conditioner, water-retaining agent, adhesive and compound fertilizer into sandy loess. The invention discloses a Chinese patent with publication number CN101371639B, which aims at solving the problems of low plant survival rate, difficult foreign soil source, high cost, secondary pollution risk of a large amount of excess sludge generated in urban domestic sewage treatment on the environment and the like existing in a reclamation method, and discloses surface soil for mining reclamation, which consists of stripping soil, tailing sand and excess sludge, wherein the weight percentages of all components are 75-80% of the stripping soil, 15-20% of the tailing sand and 1-10% of the excess sludge. The invention discloses a soilless planting substrate for recovering vegetation in a metal ore waste rock yard and a vegetation recovery construction method thereof, wherein the soilless planting substrate comprises HDS (high density fiberboard) bottom mud, rice hulls, fermented sludge, an organic polymerization crosslinking agent and a microbial agent, the HDS bottom mud is waste obtained by neutralizing mine acid wastewater with lime milk or acetylene sludge acid-base after valuable elements are recovered, namely the soilless planting substrate takes waste obtained by neutralizing the fermented sludge and the mine acid wastewater with acid-base as a main substrate and is improved by organic matters and fungi as an auxiliary material, the fermented sludge and the bottom mud have complex components, and harmful substances such as residual agents, heavy metals and the like exist in the substrate for vegetation growth for a long time, and the substrate for vegetation growth has long-term ecological risks. The Chinese patent with the publication number of CN103214300B also discloses a composite improved matrix material for ecological restoration of a coal gangue storage yard based on excess sludge, fly ash, soil, mushroom dregs and the like. Because various medicaments are mixed in the excess sludge treatment process and persistent pollutants such as heavy metals and the like remain, secondary environmental risks can be caused when the excess sludge treatment process is used as planting concrete soil dressing; on the basis, an optimized formula (publication number is CN 110683919A) for the improved matrix for the ecological restoration of the acidic weathered coal gangue yard is disclosed recently, and 25% of limestone powder and 10% of phosphate rock powder are adopted to replace residual sludge, fly ash and phosphogypsum, so that the ecological property of the improved matrix is further improved. The substrate material proposed by the patent is only used for covering the surface of the acid coal gangue storage yard by 2cm, and the cushion layer below the base layer still needs to purchase soil outside, so that the economy and sustainability of the soil and nutrition required by ecological restoration vegetation are not solved.

At present, relevant researches on utilization of river and lake bottom mud and industrial solid wastes as soil dressing are not reported.

Disclosure of Invention

The invention aims to solve the problems in the prior art, provides a foreign soil layer structure based on river and lake bottom mud and phosphorite solid waste, ensures that foreign soil can prevent plant-growing concrete filling materials from losing, ensures continuous nutrition supply requirements for plant growth, fully utilizes water environment to treat and dredge river and lake bottom mud, phosphorus slag, phosphogypsum, steel slag and other industrial solid waste, and can effectively solve the technical problems of high cost of vegetation concrete foreign soil, secondary pollution of industrial solid waste stacking on the environment and the like in the current stage.

The invention also aims to provide a preparation method of the soil layer structure of the removed soil based on the solid waste of the river and lake bottom mud and the phosphorite.

The above object of the present invention is achieved by the following means.

The soil-dressing structure is based on solid waste of river and lake bottom mud and phosphorite, the soil-dressing structure sequentially comprises a soil-dressing surface layer, a middle permeable layer and a soil-dressing base layer from top to bottom, and a contact surface between each two soil-dressing structures is a zigzag transition structure;

the soil dressing surface layer and the soil dressing base layer comprise the following raw materials in percentage by mass: 54-64% of river and lake bottom mud, 16-36% of phosphorus slag and 10-20% of humic acid organic fertilizer;

the middle permeable layer comprises the following raw materials in percentage by mass: 6 to 16 percent of phosphogypsum, 74 to 75 percent of steel slag sand and 10 to 20 percent of humic acid organic fertilizer.

The serrated transition structures and the steel slag sand are arranged between the soil layers to act together, when rainwater permeates into the surface layer of the passenger soil, the serrated transition structures increase the contact surface between the soil layers, and the penetration of the rainwater from the surface layer of the passenger soil to the base layer can be accelerated under the action of the steel slag sand in the middle permeable layer, so that the water permeation and delivery efficiency is improved, and the roots of plants are prevented from being rotten due to long-term immersion in water; meanwhile, the alien soil base layer can be used as a water retention layer, water is stored in the alien soil base layer under the action of a saw-toothed transition structure and steel slag sand, and the stored water of the alien soil base layer can be absorbed when the plants lack water, so that the water supply of the plants is guaranteed; the zigzag transition structure enables soil layer structures to be staggered with each other, so that nutrients can better permeate and are beneficial to plant absorption; the zigzag transition structure between soil layers can increase the stress effect, so that each layer of soil layer structure is more stable and has higher strength.

The river and lake bottom mud contains rich nutrient substances required by vegetation growth and flora for improving microbial habitat, and the phosphorus slag and the phosphogypsum contain a certain amount of soluble phosphorus element, calcium, sulfur and other elements, so that continuous nutrient supply can be provided for the vegetation.

Preferably, the thickness of the alien soil surface layer is 3-5cm, the thickness of the middle permeable layer is 2-4cm, the thickness of the alien soil base layer is 2-4cm, more specifically, the thickness of the alien soil surface layer is 4cm, the thickness of the middle permeable layer is 3cm, and the thickness of the alien soil base layer is 3cm.

Preferably, the sawtooth-shaped transition structure is a tooth-shaped groove, the distance between the tooth-shaped grooves is 0.5-0.8cm, and the depth is 0.5-0.8cm. More specifically, the pitch of the tooth-shaped grooves is 0.6cm, and the depth is 0.6cm.

Preferably, the river and lake bottom mud is desilting bottom mud or pipe network mud after the water environment is renovated, the water content of the river and lake bottom mud is 75% -85%, and the pH value of the river and lake bottom mud is 6.0-7.5.

Preferably, the fineness of the phosphorous slag is 100-200 meshes and P is ₂ O ₅ The content is 1.5-3.0%. The phosphorus slag is used as a dehydration conditioning raw material to perform dehydration and solidification treatment on the improvement of the dredging bottom mud of the river and the lake, so as to accelerate the rapid dehydration of the bottom mud of the river and the lake.

Preferably, the pH of the phosphogypsum is 4.5-5.5. The phosphorus slag and the phosphogypsum can act synergistically to neutralize and regulate the acidity and alkalinity of the foreign soil surface layer and the foreign soil base layer, so that the soil layer structure is more suitable for plant growth.

Preferably, the steel slag sand is drum steel slag which is sieved to obtain fine particles with the particle size of 2.35-5 mm. The steel slag sand is used for improving the water permeation and conveying efficiency.

The invention also provides a preparation method of the soil layer structure of the removed soil based on the solid waste of the river and lake bottom mud and the phosphorite, which comprises the following steps:

1) Uniformly mixing the river and lake bottom mud and the phosphorus slag, naturally stacking the stuffy materials at a rain sheltering position for 24-48 hours, discharging upper water after precipitation to enable the water content of the river and lake bottom mud to reach 50-55%, and then uniformly mixing the mixture of the river and lake bottom mud and the phosphorus slag with the humic acid organic fertilizer to obtain a material A;

2) Mixing and stirring phosphogypsum, steel slag sand and humic acid organic fertilizer for 30s to obtain a material B;

3) Paving the material A on the surface layer of the plant-growing concrete, wherein the paving thickness is 2-4cm, and thus obtaining the foreign soil base layer;

4) Setting a saw-tooth transition structure with the distance of 0.5-0.8cm and the depth of 0.5-0.8cm on the surface of the soil-dressing base layer paved in the step 3);

5) Laying the material B on the sawtooth-shaped transition structure in the step 4), and laying the material B with the thickness of 2-4cm from the top of the sawtooth-shaped transition structure to obtain the middle permeable layer;

6) Setting a saw-tooth transition structure with the interval of 0.5-0.8cm and the depth of 0.5-0.8cm on the surface of the middle water-permeable layer paved in the step 5);

7) And (3) paving the material A on the sawtooth-shaped transition structure in the step 6), and paving the material A to 3-5cm from the top of the sawtooth-shaped transition structure to obtain the surface layer of the foreign soil.

The invention takes the sediment dredged by the water environment remediation project as the raw material, adopts the phosphorus slag and the phosphogypsum in the solid waste of the phosphorite as the dehydration conditioning raw material, and the phosphorus slag carries out dehydration curing treatment on the sediment, thereby accelerating the dehydration efficiency of the sediment, shortening the treatment period, enabling the sediment to have higher strength and being more stable and difficult to slide when being used as the river channel slope protection; the river and lake bottom mud contains rich nutrient substances required by plant growth and flora for improving microbial habitat, and is supplemented with humic acid organic fertilizer to improve the nutrition level; the intermediate permeable layer of the phosphogypsum and coarse grains of the steel slag sand is supplemented with humic acid organic fertilizer, which is beneficial to adjusting the alkalinity of the upper and lower soil layers; the phosphorus slag and the phosphogypsum both contain a certain amount of soluble phosphorus, and the gradual slow release of the soluble phosphorus can provide continuous nutrition supply for the growth of surface layer plants, the invention can avoid the high cost caused by purchasing foreign soil, and can fully eliminate bottom mud and industrial solid waste generated by water environment remediation.

Compared with the prior art, the invention has the beneficial effects that:

(1) The raw materials are easy to obtain, the river and lake bottom mud is used as a soil dressing base material, the phosphorus slag is used as a dehydration conditioning raw material, the phosphorus slag and the phosphogypsum are used as a pH value adjusting material, the steel slag sand is used for improving the water permeation and transportation efficiency, all the materials are fully based on the principle of local materials, and the river and lake bottom mud, the phosphorite solid waste and the steel slag sand in the dredging engineering are utilized, so that waste materials are changed into valuable materials, the secondary utilization of waste material resources is realized, the resource utilization approach of the solid waste is widened, the solid waste accumulation occupied land is reduced, the technical problems of high cost of vegetation concrete dressing, secondary pollution of industrial solid waste accumulation to the environment and the like in the current stage are effectively solved, and the technical economic and ecological benefits are very obvious.

(2) The soil dressing structure prepared by the method is suitable for plant growth, the survival rate of plants can be improved, the phosphogypsum is acidic and the phosphorous slag is alkaline through the synergistic effect of the phosphorous slag and the phosphogypsum, and the acidity and alkalinity of the soil dressing surface layer and the soil dressing base layer can be neutralized and adjusted, so that the soil layer structure is more suitable for plant growth; the river and lake bottom mud contains rich nutrient substances required by vegetation growth and flora for improving microbial habitat, and the phosphorus slag and the phosphogypsum contain a certain amount of soluble phosphorus element, calcium, sulfur and other elements, so that continuous nutrient supply can be provided for the vegetation, and the dosage of nutrient fertilizers in the traditional soil dressing is reduced; the zigzag transition structure enables the soil layer structures to be mutually staggered, the contact surface is increased, moisture and nutrients can better permeate, plants can absorb the moisture and the fertility, and the moisture retention performance and the fertility of the soil layer structures can be simultaneously guaranteed.

(3) According to the invention, the sawtooth-shaped transition structure and the steel slag sand act together, when rainwater permeates into the surface layer of the soil, the sawtooth-shaped transition structure increases the contact surface between soil layers, and the penetration of the rainwater from the surface layer of the soil to the base layer of the soil can be accelerated under the action of the steel slag sand in the middle permeable layer, so that the water permeation and delivery efficiency is improved, and the roots of plants are prevented from being rotten due to long-term immersion in water; meanwhile, the alien soil base layer can be used as a water retention layer, water is stored in the alien soil base layer under the action of the sawtooth-shaped transition structure and the steel slag sand, and the stored water of the alien soil base layer can be absorbed when the plants lack water, so that the water supply of the plants is guaranteed.

(4) The foreign soil and soil layer structure is more stable when being used as a river course slope protection, the phosphorus slag carries out dehydration and solidification treatment on the bottom mud, the dehydration efficiency of the bottom mud can be accelerated, the treatment period is shortened, the strength of the bottom mud is increased, and the soil layer structure can be more stable when being used as the river course slope protection; secondly, the cockscomb structure between the soil horizon increases the atress effect for it is more stable between every layer of soil horizon structure, has higher intensity, can effective scour protection and prevent the landslide that causes because of the side slope is unstable when as the river course bank protection.

(5) The construction process is simple, the preparation process of the soil layer structure of the foreign soil comprises mechanical stirring and natural material stacking, the environment is not polluted, and the normal construction is not influenced.

Drawings

Fig. 1 is a schematic sectional view of a soil layer structure of the present invention.

Reference numerals are as follows: 1. a soil surface layer is removed; 2. a middle permeable layer; 3. a soil base layer is removed; 4. a plant seed; 5. a saw-toothed transition structure.

Detailed Description

The technical solutions of the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings, and it is to be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without any inventive step, are within the scope of the present invention.

As shown in figure 1, the foreign soil layer structure based on solid waste of river and lake bottom mud and phosphorite sequentially comprises a foreign soil surface layer 1, a middle permeable layer 2 and a foreign soil base layer 3 from top to bottom, plant seeds 4 are arranged on the upper layer of the foreign soil surface layer 1, the plant seeds 4 are directly sprayed and sowed within 2cm of the upper layer of the foreign soil surface layer 1, the contact surface between each layer of the foreign soil layer structure is a sawtooth-shaped transition structure 5, the sawtooth-shaped transition structure 5 is a tooth-shaped groove, the space between the tooth-shaped grooves is 0.6cm, and the depth is 0.6cm.

The preparation method of the foreign soil layer structure based on the river and lake bottom mud and the phosphorite solid waste provided by the following examples and comparative examples comprises the following steps:

1) Weighing river and lake bottom mud, phosphorus slag and a humic acid organic fertilizer according to the mass percentage of 54-64 to 16-36, uniformly mixing the river and lake bottom mud and the phosphorus slag, naturally stacking the materials in a rain sheltering place for 24-48 hours, discharging upper water after precipitation to enable the water content of the river and lake bottom mud to reach 50-55%, and uniformly mixing the mixture of the river and lake bottom mud and the phosphorus slag with the humic acid organic fertilizer to obtain a material A;

2) Weighing the phosphogypsum, the steel slag sand and the humic acid organic fertilizer according to the mass percentage of 6-16;

3) Paving the material A on the surface layer of the plant-growing concrete, wherein the paving thickness is 2-4cm, and thus obtaining the foreign soil base layer;

4) Setting a saw-tooth transition structure with the distance of 0.5-0.8cm and the depth of 0.5-0.8cm on the surface of the soil dressing base layer paved in the step 3);

5) Laying the material B on the sawtooth-shaped transition structure in the step 4), and laying the material B with the thickness of 2-4cm from the top of the sawtooth-shaped transition structure to obtain the middle permeable layer;

6) Setting a saw-tooth transition structure with the interval of 0.5-0.8cm and the depth of 0.5-0.8cm on the surface of the middle water-permeable layer paved in the step 5);

7) And (3) paving the material A on the sawtooth-shaped transition structure in the step 6), and paving the material A to 3-5cm from the top of the sawtooth-shaped transition structure to obtain the surface layer of the foreign soil.

Wherein the water content of the river and lake bottom mud is 75-85%, and the pH value is 6.0-7.5; the fineness of the phosphorous slag is 100-200 meshes and P ₂ O ₅ The content is 1.5% -3.0%; the pH value of the phosphogypsum is 4.5-5.5; the steel slag sand is drum steel slag and is screened to obtain fine particles with the particle size of 2.35-5 mm.

The humic acid organic fertilizer is a commercially available product, and the manufacturer is Handan City-sourced WoFei technology company Limited; the following embodiments use the same organic fertilizer of humic acids, which is a prior art and is not intended to limit the invention further.

Examples 1 to 5 and comparative examples 1 to 4

By adopting the preparation method of the soil layer structure of the soil for foreign land, the river and lake bottom mud of a certain water system remediation project in the horsetail area of Fuzhou city of Fujian province is selected and mixed with phosphorite solid waste for improvement test, and the material consumption and the soil layer thickness of each soil layer are as shown in the following table 1:

TABLE 1

Comparative example 5

The difference between comparative example 5 and example 1 is that no sawtooth-shaped transition structure is established in step 4) and step 6).

Comparative example 6

The difference between comparative example 6 and example 1 is that the steel slag sand is replaced with natural river sand in the middle permeable layer.

Comparative example 7

Comparative example 7 differs from example 1 in that a zigzag transition structure was established with a pitch of 0.4cm and a depth of 0.4cm.

Comparative example 8

Comparative example 8 is different from example 1 in steps 3), 5), 7) the thicknesses of the soil surface layer, the intermediate permeable layer and the soil base layer were 4, 4.5 and 3cm, respectively.

Comparative example 9

And in the comparative example 9, outsourcing soil (manufacturers: huangpi district and Qinhu Cao works in Wuhan City) and humic acid organic fertilizer are adopted, the mass percentage of the outsourcing soil to the humic acid organic fertilizer is 90 percent, the outsourcing soil and the humic acid organic fertilizer are laid on the surface layer of the vegetation concrete, the thickness of the outsourcing soil is 8cm, and meanwhile, a sawtooth transition structure is not arranged.

Application example Performance detection

And (3) within the range of 2cm on the soil surface, carrying out spray sowing on bermuda grass seeds by using the foreign soil, simulating rainfall infiltration conditions, and measuring the pH value, the shear strength, the seed germination time and the vegetation coverage rate after one month of each soil layer.

The method for testing the soil layer shear resistance inner friction angle and the cohesive force is carried out according to the regulation in GB/T50123-2019 geotechnical test method Standard.

The test results of the examples and comparative examples are shown in Table 2:

TABLE 2

By comparing the experimental data in table 2, it can be seen that:

compared with the example 1, when the using amount of the phosphorous slag is increased or the using amount of the phosphogypsum is reduced, the pH values of the upper soil layer and the lower soil layer are alkalescent and positive, and when the using amount of the phosphorous slag is reduced or the using amount of the phosphogypsum is increased, the pH values of the soil layers are lowered, so that the growth of plants is not facilitated; according to the embodiment 1-5 in the table 2, when the river and lake bottom mud, the phosphorus slag and the humic acid organic fertilizer are selected according to the mass percentage of 54-64 to 16-36, and the phosphogypsum, the steel slag sand and the humic acid organic fertilizer are selected according to the mass percentage of 6-16 to 74-75; the phosphorous slag and the phosphogypsum can act synergistically, the phosphogypsum is acidic, the phosphorous slag is alkaline, and the acidity and the alkalinity of the foreign soil surface layer and the foreign soil base layer can be neutralized and adjusted, so that the soil layer structure is more suitable for plant growth.

Compared with the embodiment 1-5, the comparative example 5 has the advantages that the serrated transition structure is not arranged, the shear strength of the soil layers is reduced, the serrated transition structure between the soil layers increases the stress effect, each layer of soil layer structure is more stable, the strength is higher, and the anti-scouring effect can be effectively realized and the landslide caused by the instability of the side slope can be prevented when the soil layer structure is used as the river channel slope protection.

Comparative examples 5 to 6 compared with example 1, when no steel slag sand was used or no zigzag transition structure was established, the water permeability of the soil layer was reduced, the water permeation and transport efficiency was slow, the plant growth was slow, and the soil layer structure was not suitable for the plant growth. The serrated transition structure and the steel slag sand act together, so that the water permeation and delivery efficiency can be improved, and the water supply of plants can be guaranteed.

Comparative example 7 compared with example 1, when the pitch of the zigzag transition structure becomes small and the depth becomes shallow, the shear strength of the soil layer structure becomes low, and the moisture permeation and transportation efficiency is low, which is not favorable for the growth of plants.

Compared with the embodiment 1, the comparative example 8 has the advantages that the thickness of the middle permeable layer is too thick, so that the middle permeable layer is not suitable for the growth of plant roots, the soil layer strength is reduced, and the middle permeable layer is not suitable for river channel revetment.

Comparative example 9 compared to example 1, with the outsourcing soil, the plant growth was slow and the soil layer shear strength was low.

According to the test results, the preparation method and the soil layer structure provided by the embodiment of the invention are beneficial to the growth of the bermuda grass, the water wettability is good after irrigation, the pH value of soil is weak acid, the internal friction angle in the shear strength is increased, the cohesive force is increased, the soil layer structure is more stable, the germination time of the bermuda grass is early, and the vegetation coverage rate of the foreign soil surface after growth for one month is high.

The soil layer structure of the foreign soil based on the solid waste of the bottom mud of the river and the lake and the phosphorite and the preparation method have wide application prospects in the fields of water environment remediation, ecological restoration of mines and slag yards and the like, and have the following beneficial effects:

(1) Resource utilization of river and lake bottom mud and industrial solid waste

A large amount of desilting bottom mud is generated in the comprehensive water environment treatment process, the open-air stacking occupies land, and secondary pollution to river channels, soil and the like can be generated after long-term rain wash; similar environmental threats can be formed by the land occupation and stockpiling of phosphorus slag, phosphogypsum and steel slag. The soil substitute prepared by the invention takes river and lake dredging bottom mud, phosphorus slag, phosphogypsum, steel slag sand and other solid wastes as raw materials; the river and lake bottom mud is used as a soil dressing base material, the phosphorus slag and the phosphogypsum are used as dehydration conditioning raw materials and alkalinity adjusting materials, the steel slag sand is used for improving the water permeation and transmission efficiency, the solid wastes are used as raw materials for preparing soil dressing, the high-value resource utilization of the wastes is realized, and the ecological benefit is very prominent.

(2) Sustained release of phosphorus for supplying nutrients and regulating pH value

Phosphorus slag and phosphogypsum are a large amount of industrial solid wastes discharged by phosphorite enterprises in China, and the treatment, disposal and resource utilization of the phosphorus slag and the phosphogypsum become important bottlenecks which disturb the innovation and development of the phosphorite enterprises. Compared with other bulk industrial solid wastes, the phosphorus slag and the phosphogypsum both contain a certain amount of soluble phosphorus elements, calcium (Ca), sulfur (S) and other elements, the phosphorus slag, river and lake bottom mud and humic acid organic fertilizers are mixed to be used as soil dressing upper and lower soil layers, the mixture of the phosphogypsum, steel slag sand and humic acid organic fertilizers is used as a water permeable layer, continuous nutrition supply can be provided for plant growth on the surface of the plant-growing concrete, the phosphogypsum is acidic, the phosphorus slag is alkaline, the internal adjustment of the pH value of the upper and lower layers and the middle water permeable layer can be realized, and the material attribute characteristics of various solid wastes are fully utilized.

(3) Excellent in economy

The traditional soil for foreign land is usually prepared by using common soil as a base material and then mixing with proper nutrient fertilizer and/or organic matter, adhesive, water-retaining agent and the like; in developed urban areas, due to the shortage of soil resources in urban areas, outsourced soil is often used as a base material, more nutrition fees and other functional materials are also needed to be doped, factors such as vehicle-mounted transportation, transportation distance and nutrition conditioning are comprehensively considered, and the cost of soil dressing is on the rise. The soil substitute provided by the invention completely depends on local river and lake dredging sediment and industrial solid waste, the cost is obviously reduced, and the economical efficiency is outstanding.

(4) The construction process is simple

In the preparation process of the plant-growing concrete alien soil based on the solid waste of the river and lake bottom mud and the phosphorite, the plant-growing concrete alien soil only needs to be prepared by directly doping a certain proportion of phosphorus slag into the river and lake bottom mud, naturally stacking the phosphorus slag to dehydrate the phosphorus slag, and mechanically and uniformly mixing the phosphorus slag with humic acid organic fertilizer, and has no adverse effect on normal construction.

(5) Easily available raw materials and good economical efficiency

The planting concrete foreign soil based on the river and lake bottom mud and the phosphorite solid waste provided by the invention fully utilizes the river and lake bottom mud, the phosphorite solid waste and the steel slag of the dredging engineering according to the local material utilization principle, widens the resource utilization way of the solid waste, does not need to purchase a soil base material from other places, and has very remarkable economic benefit.

(6) Environmental protection and no pollution

The plant-growing concrete soil provided by the invention fully utilizes river and lake bottom mud and industrial solid wastes of dredging engineering, changes waste into valuable, realizes secondary utilization of waste resources, and reduces the accumulation land occupation; the preparation process of the foreign soil comprises mechanical stirring and natural stacking of the stuffy materials, and has no pollution to the environment.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are also within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (8)

1. The soil layer structure is characterized in that the soil layer structure comprises a soil surface layer, a middle permeable layer and a soil base layer from top to bottom in sequence, and the contact surface between the soil surface layer structure and the soil base layer is a zigzag transition structure;

the soil dressing surface layer and the soil dressing base layer both comprise the following raw materials in percentage by mass: 54-64% of river and lake bottom mud, 16-36% of phosphorus slag and 10-20% of humic acid organic fertilizer;

the middle permeable layer comprises the following raw materials in percentage by mass: 6 to 16 percent of phosphogypsum, 74 to 75 percent of steel slag sand and 10 to 20 percent of humic acid organic fertilizer.

2. The foreign soil layer structure of claim 1 wherein said foreign soil surface layer has a thickness of 3-5cm, said intermediate permeable layer has a thickness of 2-4cm, and said foreign soil base layer has a thickness of 2-4cm.

3. A soil layer structure according to claim 1 wherein the jagged transition structure is a serrated groove having a pitch of 0.5 to 0.8cm and a depth of 0.5 to 0.8cm.

4. The structure of a foreign soil layer according to claim 1, wherein the river and lake bottom sludge is desilting bottom sludge or pipe network sludge after water environment remediation, the water content of the river and lake bottom sludge is 75-85%, and the pH value of the river and lake bottom sludge is 6.0-7.5.

5. According to claimThe foreign soil layer structure is characterized in that the fineness of the phosphorous slag is 100-200 meshes and P is ₂ O ₅ The content is 1.5-3.0%.

6. A subsoil layer structure according to claim 1 characterized in that said phosphogypsum has a pH value comprised between 4.5 and 5.5.

7. A soil layer structure of foreign soil as claimed in claim 1 wherein said steel slag sand is drum steel slag that has been sieved to obtain fine particles of 2.35-5mm in size.

8. Method for producing a soil layer structure of foreign soil according to any of claims 1 to 7, characterized in that it comprises the following steps:

1) Uniformly mixing the river and lake bottom mud and the phosphorus slag, naturally stacking closed materials at a rain sheltering position for 24-48 hours, discharging upper water after precipitation to enable the water content of the river and lake bottom mud to reach 50-55%, and then uniformly mixing the mixture of the river and lake bottom mud and the phosphorus slag with a humic acid organic fertilizer to obtain a material A;

2) Mixing and stirring phosphogypsum, steel slag sand and humic acid organic fertilizer for 30s to obtain a material B;

3) Paving the material A on the surface layer of the vegetation concrete, wherein the paving thickness is 2-4cm, and obtaining the foreign soil base layer;

4) Setting a saw-tooth transition structure with the distance of 0.5-0.8cm and the depth of 0.5-0.8cm on the surface of the soil-dressing base layer paved in the step 3);

5) Laying the material B on the sawtooth-shaped transition structure in the step 4), and laying the material B with the thickness of 2-4cm calculated from the top of the sawtooth-shaped transition structure to obtain the middle permeable layer;

6) Setting a saw-tooth transition structure with the interval of 0.5-0.8cm and the depth of 0.5-0.8cm on the surface of the middle water-permeable layer paved in the step 5);

7) And (3) paving the material A on the sawtooth-shaped transition structure in the step 6), and paving the material A to 3-5cm from the top of the sawtooth-shaped transition structure to obtain the surface layer of the foreign soil.

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