A method for land reclamation by sand-mud interlayer blower filling using silt-regenerated spherical sand

Abstract

The present invention discloses a method for land reclamation using a sand-mud interlayer using silt-regenerated spherical sand. The method comprises the following steps: mixing silt, powder A, and powder B, drying, crushing, adding water to form balls, curing, and carbonizing to produce the regenerated silt spherical sand; deploying a drain port, a mud delivery pipe, a sand blowing vessel, a sand transport vessel, and an elevation observation scale; and repeating the steps of blowing in a layer of dredged silt, laying a layer of geotextile, blowing in a layer of spherical sand, and laying a layer of geotextile until the design elevation is reached, thereby forming a drainage interlayer of geotextile-spherical sand-geotextile in the blown-in silt. Using dredged silt to prepare regenerated spherical sand for land reclamation can save a large amount of sand and gravel, realizing the transformation of dredged silt into valuable materials. The process is simple, low-cost, and easy to promote. The construction process of combining regenerated silt spherical sand with geotextile to form a blown-in silt interlayer can accelerate drainage and is of great significance for land reclamation.

Description

Technical Field

[0001] The present invention relates to the technical field of dredged silt blowing and filling land reclamation, and in particular to a method for blowing and filling land reclamation using sand-mud interlayers using silt-regenerated spherical sand. Background Art

[0002] Many materials can be used for landfill operations, with sand being the most preferred. Sand offers excellent permeability, rapid drainage, and relatively low deformation. However, environmental protection and the increasing scarcity of sand and gravel resources have severely constrained the speed and quality of port construction. Conventional landfill processes, however, create land with extremely high water content and low surface bearing capacity, making immediate deep reinforcement difficult. This prevents the rapid provision of usable land for project construction and makes subsequent soft foundation treatment extremely challenging.

[0003] In practical engineering applications worldwide, besides pure sand and mud fill, the most efficient method is to first blow a layer of mud, then a layer of sand. This method shortens the drainage path, speeds up consolidation, and indirectly reduces construction time. However, due to the extremely limited resources of sand and gravel, the search for new alternative materials is particularly important.

[0004] The amount of fill lost at the drain outlet is a crucial factor in controlling costs and schedules in land reclamation projects. Excessive loss can lead to waste of sediment resources, increased vessel costs, and delayed progress. Therefore, new construction techniques are needed to retain soil particles within the fill area and prevent them from clogging the drain outlets, thereby maximizing efficiency.

[0005] In recent years, dredging projects carried out across the country have produced a large amount of dredged silt with high water content. The effective use of dredged silt can effectively resolve the contradiction between the existing land occupation of storage yards and land resources.

[0006] However, in the prior art, dredged silt is used to make fill materials that can replace sand and gravel resources. However, this method of killing two birds with one stone is rarely used. Summary of the Invention

[0007] In order to solve the above-mentioned problems in construction period and technology, the purpose of the present invention is to provide a layered filling construction method for preparing silt-regenerated spherical sand for new land reclamation materials and combining it with geotextiles, which is conducive to speeding up construction progress, saving natural resources, and having strong safety and reliability.

[0008] In order to achieve the above object, the technical solution of the present invention is:

[0009] A method for land reclamation by sand-mud interlayer filling using silt-regenerated spherical sand comprises the following steps:

[0010] S1: Pretreatment: Powder A is uniformly mixed with dredged sludge after impurities are removed to obtain a mixture, the mixture is uniformly mixed with air foam to obtain foam mud, the obtained foam mud is air-dried to obtain a foam body, the obtained foam body is crushed to obtain dry soil, powder B is uniformly mixed with the dry soil to obtain a mixed powder body, the mixed powder and water are alternately added to a pelletizing plate, and green balls are obtained after the balls reach a ball size, the obtained green balls are cured to obtain cured small balls, the cured small balls are soaked and allowed to stand, and then placed in a carbonizing kettle for carbonization to obtain regenerated sludge spherical sand;

[0011] S2: Lay out the drainage outlet, mud delivery pipe, sand blowing vessel, sand transport vessel and elevation observation scale. The elevation observation scale is used to monitor the mud surface elevation in real time during the construction process of the filling area.

[0012] S3: Fill a layer of dredged silt in the filling area;

[0013] S4: Lay a layer of geotextile on top of the dredged silt filled;

[0014] S5: Blow or dump a layer of recycled silt spherical sand on top of the laid geotextile;

[0015] S6: Lay a layer of geotextile on top of the recycled silt spherical sand;

[0016] Repeat steps S3-S6 until the design elevation is reached;

[0017] S7: Drainage.

[0018] Furthermore, in step S1, the amount of the powder A is 5%-30% of the wet weight of the dredged sludge after impurities are removed, the amount of the powder B is 5%-15% of the dry soil mass, and the amount of the air foam is 2%-5% of the mass of the mixture;

[0019] The raw materials of the powder A include: 85-95wt% basic converter steel slag powder and flocculant;

[0020] The raw materials of the powder B include: 65-85 parts by weight of cement and 15-35 parts by weight of lime.

[0021] Furthermore, the flocculant includes an inorganic flocculant or a polymer flocculant;

[0022] The inorganic flocculant includes 0-15wt% aluminum sulfate and / or ferric chloride;

[0023] The polymer flocculant includes 0-5 wt% of polyethylene and / or polypropylene.

[0024] Furthermore, the carbonization method in step S1 is to perform natural curing or steam curing on the green balls, the curing period of the natural curing is not less than 7 days, and the curing period of the steam curing is not less than 3 days.

[0025] Furthermore, the CO2 concentration in the carbonization kettle in step S1 is not less than 90%, the pressure is set to 0.15-0.3 MPa, and the carbonization time is set to 1-3 hours.

[0026] Furthermore, in step S1, the rotation speed of the ball forming disk is set to 30-50 rpm and the angle is 35°-50°;

[0027] The size of the pellets is such that the diameter of the pellets is 10 mm to 15 mm.

[0028] Furthermore, in step S1, the method of soaking the cured balls and allowing them to stand is as follows: soaking the cured balls in water for no more than 30 minutes, then taking them out and allowing them to stand for 12-24 hours.

[0029] Furthermore, in step S3, a layer of dredged silt is blown into the reclamation area by using a cutter suction dredger to dig and blow the silt near the reclamation area or a grab dredger to dredge the silt and then transport the dredged silt to the reclamation area by a mud barge.

[0030] Furthermore, in step S5, the method of blowing or dumping a layer of regenerated silt spherical sand is as follows: the regenerated silt spherical sand is loaded into a mud barge, and the mud barge enters the blowing and filling area to dump the regenerated silt spherical sand for filling; when the top surface of the blowing and filling area is raised to the point where the mud barge cannot enter the blowing and filling area, a cutter suction dredger is used for blowing and filling; when the blowing and filling land area is exposed to the water surface, a belt boat is used to directly dump the regenerated silt spherical sand into the blowing and filling area.

[0031] Furthermore, the drainage method in step S7 is: draining water through the set drain ports, drain pipes or open channels, and for the local low-lying water, using a water pump to drain the water out of the filling area.

[0032] The beneficial effects of the present invention are:

[0033] (1) The present invention uses dredged silt to make regenerated spherical sand for landfill materials, which can save a large amount of natural resources of sand and gravel building materials and effectively solve the problem of insufficient sand and gravel resources;

[0034] (2) The present invention can realize the waste utilization of silt. In port construction, it is often necessary to excavate a large amount of silt. The utilization of a large amount of dredged silt solves the problem of silt disposal and realizes the transformation of dredged silt into treasure.

[0035] (3) The present invention combines recycled silt spherical sand with geotextiles to form a blown-fill silt interlayer, which can accelerate drainage. When used as a permeable cushion layer, it has a fast drainage speed due to its large voids and high permeability coefficient, making it an excellent silt-consolidated drainage cushion layer;

[0036] (4) During the implementation of the present invention, a combination of geotextiles, dredged silt, and recycled silt spherical sand is laid to achieve the purpose of controlling the large-scale loss of soil particles at the drain outlet and preventing the blockage of the drainage pipe;

[0037] (5) The preparation process of regenerated silt spherical sand is simple, low-cost, biocompatible, easy to implement, and convenient for wide promotion and use. The present invention is of great significance to land reclamation by blowing. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0039] Figure 1 This is a schematic diagram of a layered filling project of mud-and-regenerated spherical sand in a method of sand-and-mud interlayer filling and land reclamation using silt-regenerated spherical sand disclosed in an embodiment of the present invention.

[0040] In the figure: 1. Dredged silt; 2. Geotextile; 3. Recycled silt spherical sand; 4. Sand blanket; 5. Silt. DETAILED DESCRIPTION

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0042] This embodiment provides a method for land reclamation using sand-mud interlayer blown filling using silt-regenerated spherical sand, comprising the following steps:

[0043] S1: Pretreatment. This pretreatment step is the step of making regenerated silt spherical sand. The production steps are as follows:

[0044] Taking part of the dredged sludge, cleaning the large-grained stones and plant organic debris in the sludge to obtain the dredged sludge after the impurities are removed;

[0045] uniformly mixing the powder A with the dredged sludge after impurities are removed to obtain a mixture;

[0046] Mix the mixture evenly with air foam to obtain foam mud;

[0047] Drain the obtained foam mud to a nearby flat open space with a stacking thickness not exceeding 1 meter. The thickness of the mixed foam mud should be reduced as much as possible within the scope allowed by the site.

[0048] The obtained foam mud is air-dried to obtain a foam body; the air-drying method is: natural air-drying under non-continuous rainy weather conditions, or accelerated drying by a convection fan, and hot air or cold air drying can be used;

[0049] The obtained foam is crushed by a concrete mixing machine and then recovered to obtain dry soil;

[0050] The obtained dry soil is evenly mixed with powder B to obtain a mixed powder;

[0051] Alternately adding the mixed powder and water into a ball forming plate, and obtaining green balls when the diameter of the balls reaches the ball size;

[0052] Maintaining the obtained green balls;

[0053] The cured balls are soaked and allowed to stand, and then placed in a carbonizing kettle for carbonization to obtain regenerated sludge spherical sand;

[0054] S2: Laying out the drainage outlet, mud delivery pipe, sand blowing vessel, sand transport vessel and elevation observation scale, which is used to observe the mud surface elevation in real time during the construction process of the filling area;

[0055] Laying out the drain outlet: excavate the cofferdam into a trench, lay the drainage pipe, and then backfill with sandbags. The location of the drain outlet should be set according to the terrain of the fill area;

[0056] Dredger positioning: Based on the natural environment characteristics and draft requirements of the project area, several sand-blowing vessels are deployed along the axis of the dike outside the backfill area, and several sand-transporting vessels are also deployed;

[0057] Laying mud pipes: Connect several mud pipes to the sand outlet of the sand blowing ship, connect the mud pipes to the floating pipes on the water, and then use the amphibious pipe rack to connect the floating pipes to the shore pipes;

[0058] Arrange elevation observation scales: Before the start of filling construction, arrange elevation observation scales. During filling construction, the mud surface elevation will be observed in a timely manner, and the pipeline will be adjusted in a timely manner based on the observation results.

[0059] S3: Fill a layer of dredged silt 1 in the filling area;

[0060] S4: A layer of geotextile 2 is laid on top of the dredged sludge 1. The geotextile is selected to have good water permeability, and non-woven geotextiles with anti-filtration materials are usually used.

[0061] S5: Blow or dump a layer of recycled silt spherical sand 3 on top of the laid geotextile 2:

[0062] S6: Laying a layer of geotextile 2 on top of the recycled silt spherical sand 3;

[0063] Take a layer of dredged silt, lay a layer of geotextile, then dump or blow fill a layer of spherical sand, and then lay a layer of geotextile, and repeat steps S3-S6 until the design elevation is reached, that is, a layer of geotextile is formed in the blown silt. Figure 1 In the drainage sandwich of geotextile-recycled silt spherical sand-geotextile shown, the first layer of dredged silt 1 is blown over the silt 5 and sand 4 at the bottom of the filling area.

[0064] S7: Drainage.

[0065] Adding air foam to the mixture of powder A and dredged sludge after impurities are removed belongs to the foam drying method in the prior art. The foam drying method can achieve low-energy, low-cost and efficient drying of dredged sludge.

[0066] The method disclosed in the present invention for land reclamation by sand-mud interlayer filling using silt-regenerated spherical sand has the following beneficial effects:

[0067] (1) The present invention uses dredged silt to make regenerated spherical sand for landfill materials, which can save a large amount of natural resources of sand and gravel building materials and effectively solve the problem of insufficient sand and gravel resources;

[0068] (2) The present invention can realize the waste utilization of silt. In port construction, it is often necessary to excavate a large amount of silt. The utilization of a large amount of dredged silt solves the problem of silt disposal and realizes the transformation of dredged silt into treasure.

[0069] (3) The present invention combines recycled silt spherical sand with geotextiles to form a blown-fill silt interlayer, which can accelerate drainage. When used as a permeable cushion layer, it has a fast drainage speed due to its large voids and high permeability coefficient, making it an excellent silt-consolidated drainage cushion layer;

[0070] (4) During the implementation of the present invention, a combination of geotextiles, dredged silt, and recycled silt spherical sand is laid to achieve the purpose of controlling the large-scale loss of soil particles at the drain outlet and preventing the blockage of the drainage pipe;

[0071] (5) The preparation process of regenerated silt spherical sand is simple, low-cost, biocompatible, easy to implement, and convenient for wide promotion and use. The present invention is of great significance to land reclamation by blowing.

[0072] In a specific embodiment, in step S1, the amount of the powder A is 5%-30% of the wet weight of the dredged sludge after impurities are removed;

[0073] The amount of powder B is 5-15% of the mass of the dry soil;

[0074] The amount of water added to the ball forming plate is 25-40% of the mass of the mixed powder;

[0075] The amount of the air foam is 2% to 5% of the mass of the mixture obtained by mixing the powder A with the dredged sludge;

[0076] The raw materials of the powder A include: 85-95wt% basic converter steel slag powder and flocculant;

[0077] The raw materials of the powder B include: 65-85 parts by weight of cement and 15-35 parts by weight of lime.

[0078] Preferably, when the sludge moisture content is lower than 1.5 times the liquid limit, the dosage of powder A is 5%-20% of the wet weight of the dredged sludge; when the sludge moisture content is between 1.5-2.5 times the liquid limit, the dosage of powder A is 10-30% of the wet weight of the dredged sludge; when the sludge moisture content exceeds 2.5 times the liquid limit, the sludge needs to be aired and used only after the sludge moisture content is reduced to the processing range.

[0079] In order to ensure the strength of the prepared balls, the fineness of the steel slag powder in powder A should not be too fine, and the specific surface area should be between 100-200m 2 / kg. Since dredged sludge contains a large amount of water, powder A is added to the dredged sludge for flocculation and drainage. Powder A can reduce the initial moisture content of the sludge and increase the stability of the foam in the sludge, further improving the drying efficiency of the foamed sludge.

[0080] The water in the green sphere will react chemically with the dry soil containing powder A and powder B to increase the strength of the sphere. Specifically:

[0081] The incompletely hydrated steel slag in powder A is stimulated by the lime in powder B and hydrates during the green ball curing stage. The cement in powder B also hydrates at the same time. The hydration processes of the steel slag and cement are independent of each other. The reaction process is as follows:

[0082] 2(3CaO·SiO2)+6H2O→3CaO·2SiO2·3H2O+3Ca(OH)2 (1-1)

[0083] 2(2CaO·SiO2)+4H2O→3CaO·2SiO2·3H2O+Ca(OH)2 (1-2)

[0084] 3CaO·Al2O3+6H2O→3CaO·Al2O3·6H2O (1-3)4CaO·Al2O3·Fe2O3+2Ca(OH)2+10H2O→3CaO·Al2O3·6H2O+3CaO·Fe2O3·6H

[0085] (1-4)

[0086] 3CaSO4+3CaO·Al2O3+32H2O→3CaO·Al2O3·3CaSO4·32H2O (1-5)

[0087] The above reaction is reaction 1. In reaction 1, the hydration of steel slag and cement is the main source of the strength increase of the pellets.

[0088] Since the lime in powder B provides a higher alkalinity for the pore solution, Si and Al in the clay minerals in the dredged soil are dissolved and react with Ca 2 The + ions further undergo a pozzolanic reaction to generate hydration products such as calcium silicate hydrate (CSH), calcium aluminate hydrate (CAH), and calcium aluminosilicate hydrate (CASH), which fill the soil pores and further improve the strength of the sphere. This reaction is Reaction 2. The effects of the hydration reaction in Reaction 1 and the pozzolanic reaction in Reaction 2 on the strength of the spherical sand increase with increasing curing time.

[0089] The purpose of carbonization treatment after ball sand molding and curing is to reduce the alkalinity of the spheres, forming a dense shell on the spheres to reduce the risk of leaching of dredged soil pollutants, thereby achieving harmless treatment of groundwater and nearby waters. The reactions involved are: carbonization of Ca(OH)2 in the hydration products of steel slag and cement, and carbonization of C2S (dicalcium silicate, 2CaO·SiO2) minerals in the incompletely hydrated steel slag. The reaction equation is:

[0090] Ca(OH)2+CO2→CaCO3+H2O (1-6)

[0091] 2CaO·SiO2+2CO2+nH2O→SiO2·nH2O+2CaCO3 (1-7)

[0092] In the present application, the hydration activity of C2S, the main mineral of steel slag in powder A, is extremely low, so the loss of C2S during the drying process is relatively small. During the maintenance of the green balls, the present application uses alkaline powder B to stimulate the hydration activity of the unhydrated C2S in powder A, so that the unhydrated C2S after the hydration activity is stimulated undergoes a hydration reaction, and the C2S minerals that are not fully stimulated can continue to react in the carbonization treatment step to provide strength for the sphere. A large amount of powder A is added during the preparation of dredged sludge regenerated spherical sand to assist in the rapid drying of the viscous mud. However, the powder A added during the drying stage will not be wasted, but will serve as an important reactant in subsequent treatments, thereby achieving the role of powder A in assisting the drying of the mud and fully utilizing the large amount of powder A.

[0093] In a specific embodiment, the flocculant includes an inorganic flocculant or a polymer flocculant;

[0094] The inorganic flocculant includes 0-15 wt% of at least one of aluminum sulfate and ferric chloride;

[0095] The polymer flocculant includes 0-5 wt% of polyethylene and / or polypropylene. The flocculant can improve the strength of the prepared green pellets and improve their stability after drying.

[0096] In a specific embodiment, the carbonization method in step S1 is to perform natural curing or steam curing on the green pellets, wherein the curing period of the natural curing is not less than 7 days, and the curing period of the steam curing is not less than 3 days. The curing time is set to ensure the strength of the pellets after curing.

[0097] In a specific embodiment, the CO2 concentration in the carbonization kettle in step S1 is not less than 90%, the pressure is set to 0.15-0.3 MPa, and the carbonization time is set to 1-3 hours. The CO2 concentration, pressure, and carbonization time are set to ensure the alkalinity of the spheres, thereby ensuring the density of the spheres and achieving the effect of forming a dense shell of the spheres.

[0098] In a specific embodiment, in step S1, the rotation speed of the ball forming disk is set to 30-50 rpm and the angle is 35°-50°;

[0099] The diameter of the pellets is 10mm-15mm. The size of the regenerated spherical sand particles can be adjusted by controlling the rotation speed and angle of the pelletizing disc, the number of feeding times and the pelletizing time.

[0100] In a specific embodiment, the method of soaking the cured balls and allowing them to stand in step S1 is: soaking the cured balls in water for no more than 30 minutes, then taking them out and allowing them to stand for 12-24 hours.

[0101] In a specific embodiment, the method for filling the reclamation area with a layer of dredged silt in step S3 is to use a cutter suction dredger to excavate and fill the area near the reclamation area simultaneously, or to use a grab dredger to dredge the dredged silt and then transport it to the reclamation area via a mud barge. If a suitable excavation area is available near the construction project, the cutter suction dredger can be used to excavate and fill the area near the reclamation area simultaneously. If there is no suitable excavation area but conditions exist for selective filling, a grab dredger can be used to excavate the silt, and a mud barge can be arranged on-site to transport the dredged silt as needed. The equipment and method for dredged silt filling are determined based on the actual project conditions.

[0102] In a specific embodiment, the method of blowing or dumping a layer of regenerated silt spherical sand in step S5 is: the regenerated silt spherical sand is loaded into a mud barge, and the mud barge enters the blowing and filling area to dump the regenerated silt spherical sand. When the top surface of the blowing and filling area is raised to the point where the mud barge cannot enter the blowing and filling area, a suction dredger is used for blowing and filling. When the blowing and filling land area is exposed to the water surface, a belt boat is used to directly dump it into the blowing and filling area.

[0103] In a specific embodiment, the drainage method in step S7 is to drain water through a set drain outlet, drainage pipe or open channel. For local low-lying water, a water pump is used to drain the water out of the filling area. Draining the water outside the filling area can promote the improvement of the bearing capacity of the surface soil.

[0104] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for land reclamation by sand-mud interlayer filling using silt-regenerated spherical sand, characterized in that: The following steps are involved: S1： Pretreatment: Powder A is uniformly mixed with dredged sludge after impurities are removed to obtain a mixture, the mixture is uniformly mixed with air foam to obtain foam slurry, the obtained foam slurry is air-dried to obtain a foam body, the obtained foam body is crushed to obtain dry soil, powder B is uniformly mixed with dry soil to obtain a mixed powder body, the mixed powder and water are alternately added to a ball-forming plate, and regenerated balls are obtained after the balls reach a ball size, the obtained regenerated balls are cured to obtain cured balls, the cured balls are soaked and allowed to stand, and then placed in a carbonization kettle for carbonization to obtain regenerated sludge spherical sand; The raw materials of the powder A include: 85-95wt% basic converter steel slag powder and flocculant; The raw materials of the powder B include: 65-85 parts by weight of cement and 15-35 parts by weight of lime; S2: Lay out the drainage outlet, mud delivery pipe, sand blowing vessel, sand transport vessel and elevation observation scale. The elevation observation scale is used to monitor the mud surface elevation in real time during the construction process of the filling area. S3: Fill a layer of dredged silt in the filling area; S4: Lay a layer of geotextile on top of the dredged silt filled; S5: Blow or dump a layer of recycled silt spherical sand on top of the laid geotextile; S6: Lay a layer of geotextile on top of the recycled silt spherical sand; Repeat steps S3-S6 until the design elevation is reached; S7: Drainage.

2. The method for land reclamation by sand-mud interlayer filling using silt-regenerated spherical sand according to claim 1, characterized in that: In step S1, the amount of powder A is 5%-30% of the wet weight of the dredged sludge after impurities are removed, the amount of powder B is 5%-15% of the dry soil mass, and the amount of air foam is 2%-5% of the mixture mass.

3. The method for land reclamation by sand-mud interlayer filling using silt-regenerated spherical sand according to claim 2, characterized in that: The flocculant includes an inorganic flocculant or a polymer flocculant; The inorganic flocculant includes 0-15wt% aluminum sulfate and / or ferric chloride; The polymer flocculant includes 0-5 wt% of polyethylene and / or polypropylene.

4. The method for land reclamation by sand-mud interlayer filling using silt-regenerated spherical sand according to claim 1, characterized in that: The curing in step S1 is natural curing or steam curing of the regenerated balls. The curing period of the natural curing is not less than 7 days, and the curing period of the steam curing is not less than 3 days.

5. The method for land reclamation by sand-mud interlayer filling using silt-regenerated spherical sand according to claim 1, characterized in that: The CO2 concentration in the carbonization kettle in step S1 is not less than 90%, the pressure is set to 0.15-0.3 MPa, and the carbonization time is set to 1-3 hours.

6. The method for land reclamation by sand-mud interlayer filling using silt-regenerated spherical sand according to claim 1, characterized in that: In step S1, the ball forming disk has a rotation speed of 30-50 rpm and an angle of 35°-50°; The size of the pellets is such that the diameter of the pellets is 10 mm to 15 mm.

7. The method for land reclamation by sand-mud interlayer filling using silt-regenerated spherical sand according to claim 1, characterized in that: In step S1, the method of soaking the cured balls and allowing them to stand is as follows: soaking the cured balls in water for no more than 30 minutes, then taking them out and allowing them to stand for 12-24 hours.

8. The method for land reclamation by sand-mud interlayer filling using silt-regenerated spherical sand according to claim 1, characterized in that: In step S3, a layer of dredged silt is blown into the reclamation area by using a cutter suction dredger to dig and blow the silt near the reclamation area, or by using a grab dredger to dredge the silt and then transporting the dredged silt to the reclamation area by a silt barge.

9. The method for land reclamation by sand-mud interlayer filling using silt-regenerated spherical sand according to claim 1, characterized in that: In step S5, the method of blowing or dumping a layer of regenerated silt spherical sand is as follows: the regenerated silt spherical sand is loaded into a mud barge, and the mud barge enters the blowing and filling area to dump the regenerated silt spherical sand. When the top surface of the blowing and filling area is raised to the point where the mud barge cannot enter the blowing and filling area, a cutter suction dredger is used for blowing and filling. When the blowing and filling land area is exposed to the water surface, a belt boat is used to directly dump the regenerated silt spherical sand into the blowing and filling area.

10. The method for land reclamation by sand-mud interlayer filling using silt-regenerated spherical sand according to claim 1, characterized in that: The drainage method in step S7 is: draining water through the set drain outlet, drainage pipe or open channel. For the local low-lying water, a water pump is used to discharge the water out of the filling area.

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