Polluted bottom mud collecting and removing method based on terrain transformation

Abstract

According to the technical scheme, the polluted bottom mud collecting and removing method comprises the following steps that a mud collecting tank is constructed at the bottom of a lake desilting area, and the center of the low-lying position of the mud collecting tank extends downwards to construct a mud well; the peripheral sludge is collected to the low-lying position of the sludge collecting groove and the interior of the sludge well through the sludge scraping equipment; the outer sleeve is vertically put down to the position above the low-lying position of the sludge collecting tank, so that the outer sleeve completely covers the sludge well, a lower end sleeve opening sinks into sludge at the low-lying position, and an upper end sleeve opening is exposed out of the water surface; water in the outer sleeve is pumped out; sludge collected in the outer sleeve and the sludge well is removed; the peripheral sludge is collected into a sludge collecting groove in the periphery of the outer sleeve through the gravity gathering effect and / or sludge scraping equipment; the outer sleeve is lifted until the bottom opening of the outer sleeve is lower than the mud surface at the low-lying position, and external sludge flows into the sludge well under the action of hydrostatic pressure to form secondary sludge collection; and repeating the step of clearing the secondary collected sludge until the sludge is cleared. The scheme has the advantages of improving the sludge collection efficiency, reducing the water content and reducing water disturbance.

Description

Technical Field

[0001] The present invention relates to the technical field of lake dredging, and in particular to a method for collecting and removing contaminated bottom mud based on terrain transformation. Background Art

[0002] Removing endogenously contaminated sediment from the bottoms of lakes and reservoirs is a critical step in water environment management. Existing removal technologies generally suffer from low removal efficiency, high moisture content in the removed sediment, and difficulties in subsequent disposal. To address these issues, a comprehensive, integrated technology for the routine and precise treatment of contaminated sediment has been developed. By integrating a multifunctional dredging platform and a wheeled, low-disturbance scraper, this technology significantly improves sediment removal efficiency and reduces moisture content.

[0003] The closest existing technology utilizes a "lake bottom silt capture tank" structure. Based on lake flow simulations to determine sediment settling areas, steel or sheet pile-supported silt capture tanks are deployed, relying on the natural flow of water to collect floating and flowing silt. Water excavators are then used to periodically remove silt from the tanks. This solution has efficiency bottlenecks. Relying solely on natural sedimentation by water flow results in a low silt collection rate; the scraping, collecting, and retrieval steps must be performed sequentially, resulting in overall low efficiency. The process can easily cause water disturbance and turbidity, damaging the ecological environment. The cleared silt has a high moisture content, requiring the addition of flocculants. Because it contains chemicals, it cannot be used in farmland or landscaping, and can only be disposed of in landscaping.

[0004] Although the aforementioned complete set of technologies improves collection efficiency through active sludge scraping, its serial process still has inherent defects. Sludge scraping and sludge collection cannot be carried out simultaneously, and the project efficiency is restricted by the operating speed of a single link; high water content sludge increases subsequent dehydration costs and disposal difficulties.

[0005] In view of the above problems, the existing technology is in urgent need of improvement. Summary of the Invention

[0006] In order to solve the above problems, the purpose of the present invention is to provide a method for collecting and removing contaminated sediment based on terrain transformation, which has the advantages of improving sludge collection efficiency, reducing water content and reducing water disturbance.

[0007] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions:

[0008] The present application provides a method for collecting and removing contaminated sediment based on landform transformation, and the technical solution is as follows: step (1), constructing a sludge collecting trough at the bottom of the lake desilting area, and extending downward from the center of the low-lying part of the sludge collecting trough to construct a sludge well; step (2), collecting the surrounding sludge into the low-lying part of the sludge collecting trough and the sludge well by a sludge scraping device;

[0009] Step (3), vertically lower the outer sleeve to the top of the low-lying part of the mud collecting tank, so that the outer sleeve completely covers the mud well and the lower end of the sleeve is sunken into the mud in the low-lying part, and the upper end of the sleeve is exposed to the water surface;

[0010] Step (4), pumping out the water inside the outer sleeve;

[0011] Step (5), removing the silt collected in the outer sleeve and the silt well;

[0012] Step (6), collecting the surrounding sludge into a sludge collecting tank on the periphery of the outer sleeve by gravity aggregation and / or scraping equipment;

[0013] Step (7), lifting the outer sleeve until the bottom opening thereof is lower than the mud surface height in the low-lying area, and the external silt flows into the silt well under the action of hydrostatic pressure to form a secondary silt collection;

[0014] Step (8), repeating steps (5)-(7) to remove the secondary collected sludge until the sludge is completely cleared;

[0015] The operations of step (5) and step (6) can be performed step by step or simultaneously.

[0016] This technical solution forms a graded mud collection structure by constructing a mud collection trough and a mud well, and realizes the parallel operation of mud scraping and mud collection by combining the dynamic control of the outer sleeve. The mud collection trough and mud well established in step (1) constitute a sedimentation area, and the mud is quickly collected by actively scraping the mud in step (2); step (3) lowers the outer sleeve to form a closed space, and step (4) forms a waterless environment after pumping water, which promotes step (5) to efficiently remove high-concentration mud; when step (6) continuously collects mud outside the outer sleeve, step (7) accurately controls the lifting height of the outer sleeve and uses hydrostatic pressure to drive the external mud to flow into the mud well for the second time, thereby realizing an uninterrupted "mud collection-dredging" cycle. The repeated operation of step (8) forms a dynamic balance, which not only avoids the waiting time of traditional serial operation, but also reduces the water content of mud by physical precipitation. Among them, the vertical lowering and lifting height control of the outer sleeve not only ensures the closed operation to reduce water disturbance, but also realizes the self-flow of mud by hydrostatic pressure. The dual effects improve the dredging efficiency and reduce the dewatering cost. This solution uses a mud collecting trough, an outer sleeve, and water pumping to maintain the low moisture content of the discharged sludge while realizing parallel operation of the mud scraping and mud collection processes, thereby improving operating efficiency while still being compatible with the existing basket mud collection method.

[0017] Furthermore, the present application also proposes that the diameter of the outer sleeve is larger than the diameter of the sludge well and smaller than the maximum diameter of the low-lying part in the sludge collecting tank. By limiting the two-way constraint relationship of the outer sleeve diameter, a synergistic effect is formed. The outer sleeve diameter is larger than the sludge well diameter to ensure that it completely covers the sludge well opening and prevents the sludge in the well from overflowing during the pumping process; at the same time, the diameter is smaller than the maximum diameter of the low-lying part of the sludge collecting tank, so that the outer sleeve can be accurately embedded in the sludge layer in the low-lying part when it sinks, forming a closed pumping space. This size matching ensures that the external sludge can effectively flow into the bottom of the outer sleeve through hydrostatic pressure during secondary sludge collection, and avoids the damage to the sludge collecting tank structure or the spread of sludge to non-target areas due to the outer sleeve being too large.

[0018] Furthermore, the present application also proposes that a rigid cylinder is pre-buried in the sludge well. By pre-buried a rigid cylinder inside the sludge well, the compressive resistance and structural stability of the rigid material are utilized to prevent the well wall from collapsing due to external water pressure or bottom mud fluidity, thereby ensuring that the sludge well maintains a preset shape during long-term mud collection operations. The presence of the rigid cylinder forms a physical isolation barrier, which not only prevents the sludge accumulated in the well from mixing with the surrounding loose bottom mud, but also reduces the disturbance of the soil around the well wall during the operation of the dredging equipment, thereby reducing the risk of secondary suspension of bottom mud particles to pollute the water body. In addition, as a pre-buried structure, the rigid cylinder can pre-control the diameter and depth parameters of the sludge well, providing the basic conditions for size matching for the subsequent precise lowering of the outer sleeve and hydrostatic pressure-driven secondary mud collection.

[0019] Furthermore, the present application also proposes that in step (7), the outer sleeve is lifted until the height of its bottom opening is lower than the height of the top surface of the mud collecting trough at the edge of the low-lying area. This height control not only avoids the excessive lifting of the outer sleeve, which causes the opening between the silt well and the mud collecting trough to be too large, resulting in the influx of lake water, but also ensures that the silt can continue to flow into the well stably during the secondary mud collection process. This technical means transforms the mud collection mode that passively relies on the natural deposition of water flow into an active drainage mode based on pressure difference by precisely controlling the spatial position of the outer sleeve, and can ensure that lake water does not enter the outer sleeve, thereby maintaining the low water content characteristic of the discharged silt.

[0020] Furthermore, the present application also proposes that in step (7), when the outer sleeve is lifted, if silt is found to flow into the low-lying area and the silt well along with the lake water, the outer sleeve height is immediately lowered to prevent water from entering. This technical solution controls the sealing of the silt well by dynamically adjusting the height of the outer sleeve. During the operation of lifting the outer sleeve, the water inflow into the low-lying area and the silt well is monitored in real time. When the inflow of the silt and lake water mixture is detected, the outer sleeve height is immediately lowered so that the bottom opening of the outer sleeve re-forms a physical barrier.

[0021] Furthermore, the present application also proposes to use a work platform floating on the water surface and a lifting device mounted thereon to perform the following operations:

[0022] Use the lifting device to lower the outer sleeve vertically to the top of the low-lying part of the mud collecting tank;

[0023] Use the lifting device to lift the water pump into the outer sleeve to pump water;

[0024] Use a lifting device to operate the grab bucket to remove silt;

[0025] Lift the outer sleeve by means of a lifting device.

[0026] This technical solution achieves integrated control of the dredging process by establishing a collaborative operating system between a surface work platform and a lifting device. Using a floating work platform as a mobile workstation, it can flexibly adapt to the needs of different waters, avoiding the water depth limitations of traditional fixed equipment. The multifunctional lifting characteristics of the lifting device enable precise positioning of the outer sleeve, rapid deployment of the water pump, and dredging operations with the grab bucket, forming a closed-loop operation chain, breaking the waiting time bottleneck of traditional serial processes.

[0027] Furthermore, this application also proposes:

[0028] Step (1) includes the following sub-steps:

[0029] Step (1.1): select the river confluence in the lake as the desilting area, construct a mud collection trough at the bottom of the desilting area, and extend downward from the center of the low-lying part of the mud collection trough to construct a mud well;

[0030] Step (1.2): Install a permeable sediment trap behind the mud collecting trough in the direction of the river confluence.

[0031] This technical solution achieves the dual goals of efficient mud collection and anti-diffusion by optimizing the selection of dredging areas and adding physical interception devices. First, the river confluence is used as the dredging area, and the natural sedimentation characteristics of the sediment carried by the water flow here are utilized to construct a mud collection trough and a mud well at the bottom to form a directional mud collection channel, which is more in line with the laws of fluid mechanics than the random layout of the mud collection structure. Secondly, a permeable sand-trapping device is set on the back side of the mud collection trough. Its permeability allows water to pass through but blocks the diffusion of mud, avoiding the water flow turbulence caused by the complete interception of the traditional cofferdam, and preventing the collected silt from being re-dispersed by the water flow. The layout direction of the sand-trapping device corresponds to the direction of the river confluence, ensuring that the upstream sand is intercepted without affecting the downstream water flow, thereby achieving a synergistic effect of improving mud collection efficiency and reducing ecological disturbance.

[0032] Furthermore, the present application also proposes that the mud collecting trough is constructed as a linear trough, and its extension direction intersects with the direction of the river confluence; the setting direction of the sand retaining device is consistent with the extension direction of the mud collecting trough. By designing the mud collecting trough as a linear trough structure and making its extension direction intersect with the direction of the river confluence, the interception area of the mud collecting trough in the direction of river flow can be effectively expanded, and the interception effect of the mud entering the lake with the water flow can be enhanced, avoiding the problem of mud bypassing the trough body and being unable to be collected due to the direction of the mud collecting trough being parallel to the direction of the water flow. At the same time, the setting method of the sand retaining device and the mud collecting trough extending in the same direction allows the barrier belt formed by the enclosure to form a continuous barrier along the length of the mud collecting trough, further preventing the mud not captured by the mud collecting trough from diffusing into the interior of the lake, thereby realizing the coordinated interception of the mud collecting trough and the sand retaining device in the spatial layout, and improving the overall dredging efficiency.

[0033] Furthermore, the present application also proposes that the sand trapping device includes:

[0034] Multiple floats floating on the water surface at the confluence of the river;

[0035] A permeable net with its upper end fixed on the float and its lower end below the water surface;

[0036] Fixing piles to secure the floats and permeable net to the lake bed.

[0037] This technical solution achieves efficient sediment interception through the synergistic effect of a three-layer structure. Floating buoys provide dynamic support for the permeable net, allowing it to automatically adjust its vertical position as the water level fluctuates, preventing the net from moving out of its effective interception zone due to water level fluctuations. The permeable net is arranged with its upper end fixed to the buoys and its lower end extending below the water surface, forming a continuous filtration barrier from the water surface to the lakebed. This allows water to pass through, reducing hydraulic impact, while also intercepting suspended sediment particles. Fixed piles anchor the buoys and permeable net to the lakebed, preventing structural failure caused by water impact.

[0038] Furthermore, the sand-trapping device comprises:

[0039] - a permeable net below the water surface;

[0040] -Fixing piles to secure the permeable net to the lake bed.

[0041] Furthermore, the present application also proposes that the bottom of the permeable net extends to a position close to the surface of the lake bed. By extending the bottom of the permeable net to a position close to the surface of the lake bed, a continuous interception barrier is formed from the water surface to the near surface of the lake bed, which not only makes up for the sediment escape channel caused by the suspension of the bottom of the traditional enclosure, but also retains the pore structure characteristics of the permeable net itself. On the one hand, this design inhibits the bottom silt from bypassing the enclosure and diffusing into the interior of the lake under the impact of river confluence through physical blocking. On the other hand, through the flexible contact mode of the permeable net and the lake bed surface that is not completely in contact, it avoids the destruction of the benthic habitat caused by the direct compression of the lake bed by the rigid structure, and allows some water to seep slowly through the mesh holes, preventing the local vortex from scouring the lake bed due to the complete interruption of water flow.

[0042] From the above, it can be seen that the present application provides a method and system for collecting and removing contaminated sludge based on terrain transformation. By constructing a sludge collection trough and a sludge well combined with an outer sleeve to collect sludge in stages, and using hydrostatic pressure to achieve secondary sludge collection, it solves the problems of low sludge collection efficiency, high water content and water disturbance in the existing technology, and has the advantages of improving sludge collection efficiency, reducing water content and reducing water disturbance. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Schematic diagram of step 3 of a method for collecting and removing contaminated sediment based on terrain modification provided in this application.

[0044] Figure 2 Schematic diagram of step 4 of a method for collecting and removing contaminated sediment based on terrain modification provided in this application.

[0045] Figure 3 Schematic diagram of step 5 of a method for collecting and removing contaminated sediment based on terrain modification provided in this application.

[0046] Figure 4 Schematic diagram of step 7 of a method for collecting and removing contaminated sediment based on terrain modification provided in this application.

[0047] Figure 5 A top view schematic diagram of a method for collecting and removing contaminated sediment based on terrain modification provided in this application.

[0048] Figure 6 A top view schematic diagram of the contaminated sediment collection and removal method based on landform modification at the river confluence.

[0049] Figure 7 A side view schematic diagram of a method for collecting and removing contaminated sediment based on landform modification at a river confluence.

[0050] Figure 8 A schematic diagram of the front view of the contaminated sediment collection and removal method based on landform modification at the river confluence.

[0051] Figure 9 This is a front view schematic diagram of the second type of sediment retention device implemented at the river confluence. DETAILED DESCRIPTION

[0052] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0053] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0054] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more, unless otherwise explicitly specified.

[0055] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0056] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0057] In existing technologies, the removal of endogenously contaminated sediment at the bottom of lakes and reservoirs is a key step in water environment management. However, existing technologies generally suffer from low removal efficiency, high water content in the cleared sediment, and difficulty in subsequent disposal. The closest existing technology uses steel sludge capture tanks that rely on natural sedimentation by water flow to collect sludge, but this suffers from problems such as low collection rates, low efficiency due to the need to perform scraping and sludge collection sequentially, and the turbidity and disturbance of the water body caused by the operation process. For example, in lake dredging projects, traditional methods require waiting for the scraping to be completed before sludge collection can be performed, and the cleared sludge needs to be treated with chemical agents due to its high water content, making it impossible to recycle it as a resource.

[0058] To address this issue, the inventors discovered that existing technologies were unable to simultaneously scrape and collect mud, resulting in long engineering cycles and high costs. Analysis revealed that creating a closed environment during the mud collection process for physical dehydration, while simultaneously enabling continuous external sludge replenishment through structural design, could overcome the efficiency bottleneck. Based on this, they proposed installing a vertically adjustable outer sleeve within the mud collection tank, utilizing hydrostatic pressure to drive the secondary flow of sludge, thereby constructing a dynamic mud collection and desilting cycle.

[0059] Therefore, Figure 1-5 As shown, this embodiment proposes a method for collecting and removing contaminated sediment based on landform transformation, comprising the following steps:

[0060] Step (1) constructing a sludge collecting trough 10 at the bottom of the lake desilting area, and extending downward from the center of the low-lying area 101 of the sludge collecting trough 10 to construct a sludge well 3;

[0061] Step (2), collecting the surrounding sludge into the low-lying area 101 of the sludge collecting tank 10 and the sludge well 3 by means of a sludge scraping device;

[0062] Step (3), vertically lower the outer sleeve 4 to above the low-lying area 101 of the mud collecting tank 10, so that the outer sleeve 4 completely covers the mud well 3 and the lower end of the sleeve is immersed in the mud in the low-lying area 101, and the upper end of the sleeve is exposed to the water surface;

[0063] Step (4), removing the water inside the outer sleeve 4;

[0064] Step (5), removing the silt collected in the outer sleeve 4 and the silt well 3;

[0065] Step (6), collecting the surrounding silt into the sludge collecting tank 10 outside the outer sleeve 4 by gravity aggregation and / or scraping equipment; Step (7), lifting the outer sleeve 4 until its bottom opening is lower than the mud surface height of the low-lying area 101, and the external silt flows into the sludge well 3 under the action of hydrostatic pressure to form secondary sludge collection;

[0066] Step (8), repeating the clearing and lifting operations of steps (5)-(7) to clear the secondary collected sludge until the sludge is cleared; wherein, the operations of step (5) and step (6) can be performed step by step or simultaneously.

[0067] In this solution, the sludge collecting trough 10 refers to a groove structure constructed at the bottom of the lake, which is used to collect the surrounding silt. Specifically, it can be formed by excavation equipment, and its low-lying area 101 is designed to help the silt settle naturally. The silt well 3 refers to a vertical shaft structure extending downward from the low-lying area 101 of the sludge collecting trough 10. The structural stability can be enhanced by pre-buried rigid cylinders, and it is used for centralized storage of high-concentration silt. The outer sleeve 4 refers to a vertically movable cylindrical structure. When lowered, it forms a closed space to facilitate pumping operations. When lifted, it triggers hydrostatic pressure to drive the silt to flow by controlling the opening height. The effect of hydrostatic pressure refers to the physical phenomenon of forming a water level difference inside and outside the cylinder by adjusting the height of the outer sleeve 4, and using the water pressure difference to drive the peripheral silt to flow into the well.

[0068] The method first forms a primary sludge collection area by constructing a sludge collecting trough 10, and the scraping equipment quickly collects the dispersed sludge to the low-lying area 101. After the outer sleeve 4 is lowered, a closed space is formed, and the internal water body is pumped out to naturally dehydrate the sludge. At this time, high-concentration sludge can be removed efficiently. During the removal operation, the outer sludge collecting trough 10 continues to collect new sludge. There are two methods for collecting new sludge. The first is to collect the sludge by gravity, which is relatively inefficient, but does not require additional operation. The other option is to use scraping equipment for scraping, which has a higher sludge collection efficiency. When the outer sleeve 4 is lifted to a specific height, the external sludge automatically flows into the well driven by hydrostatic pressure to form secondary sludge collection. This process realizes the parallel operation of scraping and collecting sludge by alternating closed dredging and open sludge collection, while using physical precipitation to reduce the water content.

[0069] Compared with the existing technology, the traditional method relies on natural sedimentation and requires the execution of each link in sequence, while the present solution realizes the spatial separation and temporal overlap of mud collection and dredging through the adjustable outer sleeve 4. In the existing technology, the sludge capture tank can only collect passively. The present solution actively drives the secondary flow of sludge through hydrostatic pressure to form a continuous replenishment mechanism. In addition, the traditional dredging process is prone to cause water turbidity due to open operation. The present solution reduces water disturbance through the closed operation of the outer sleeve 4 to avoid secondary pollution. Through the above technical solution, the present application realizes the simultaneous execution of mud scraping operation and mud collection operation, effectively shortening the dredging cycle. The physical precipitation principle is used to reduce the water content of the sludge, reduce the subsequent dehydration treatment cost, and because no flocculants are added, it can be directly used in farmland and gardens. The closed dredging operation reduces water disturbance and avoids the impact of the diffusion of suspended matter on the ecological environment. By dynamically adjusting the height of the outer sleeve 4, a continuous mud collection-dredging cycle is formed, which significantly improves the amount of sludge treated per unit time.

[0070] In a further solution, the diameter of the outer sleeve 4 is larger than the diameter of the sludge well 3 and smaller than the maximum diameter of the low-lying area 101 in the sludge collecting trough 10. The diameter of the outer sleeve 4 refers to the maximum outer edge size of its cross section, which can be achieved by using a steel cylinder or a polygonal cylinder. This size must meet the operational requirements of completely covering the opening of the sludge well 3. The diameter of the sludge well 3 refers to the cross-sectional size of its wellhead, which can be achieved by pre-buried rigid cylinders or mechanical excavation to form a vertical well. This size must match the physical properties of the natural sedimentation of sludge. The maximum diameter of the low-lying area 101 in the sludge collecting trough 10 refers to the maximum horizontal expansion range of the sludge collection area. It can be formed by mechanical excavation after determining the trough contour through underwater topographic mapping. This size must meet the coverage requirements of the operating radius of the scraping equipment. This solution forms a closed operating space to prevent sludge from flowing in during the pumping stage by limiting the size matching relationship between the outer sleeve 4 and the surrounding structure, and establishes a directional sludge conveying channel through the annular gap during the secondary sludge collection stage, thereby achieving a synergistic improvement in sludge collection efficiency and anti-diffusion capability.

[0071] Furthermore, it is proposed to pre-embed a rigid cylinder in the silt well 3. The rigid cylinder refers to a cylindrical structure made of high-strength material, which can be realized by steel or concrete pipes. Its function is to resist external soil pressure and water pressure through its own rigidity and maintain the geometric shape of the silt well 3. Pre-embedding refers to the simultaneous installation of the rigid cylinder when constructing the silt well 3. It can be realized by vibration pipe sinking method or drilling and burying process. This operation makes the rigid cylinder form a close contact with the surrounding soil, and enhances the integrity of the structure through the synergistic effect of the structure and the soil. Specifically, in the stage of constructing the silt well 3 by extending downward from the low-lying part 101 of the sludge collecting trough 10, the rigid cylinder is vertically implanted into the lakebed formation. When the scraping equipment collects silt into the sludge collecting trough 10, a smooth interface is formed on the inner wall of the rigid cylinder, guiding the silt to settle and gather in the vertical direction. When the outer sleeve 4 is lowered, the outer diameter of the rigid cylinder and the inner diameter of the outer sleeve 4 form a size matching relationship. During the well sludge removal process, the rigid cylinder isolates the grab bucket's mechanical force from the surrounding soil, preventing loose sediment particles from dispersing into the water column. During the secondary sludge collection phase, the rigid cylinder maintains the effective volume of sludge well 3, providing a stable channel boundary for hydrostatic pressure-driven external sludge backfill.

[0072] In a further embodiment, in step (7), the outer sleeve 4 is lifted to a height where the bottom opening is lower than the top surface height of the mud collecting trough 10 at the edge of the low-lying area 101. The bottom opening height refers to the vertical position of the lower end of the outer sleeve 4, which can be achieved by measuring the relative height difference between the bottom of the outer sleeve 4 and the top surface of the mud collecting trough 10, for example, by using a height sensor on a lifting device for real-time monitoring. The top surface height of the mud collecting trough 10 at the edge of the low-lying area 101 refers to the highest point position of the mud collecting trough 10 outside the low-lying area, which can be determined by underwater three-dimensional terrain scanning, for example, by using sonar equipment to perform terrain mapping of the dredging area and then establish an elevation model. Specifically, when the outer sleeve 4 is lifted to a point where the bottom opening is lower than the top surface of the mud collecting trough 10, the external silt forms a flow path along the space between the top surface of the mud collecting trough 10 and the outer sleeve 4 under the drive of the hydrostatic pressure difference. At this time, the silt well 3 is connected to the inside of the outer sleeve 4, and the external silt continues to flow into the well through this path to complete the secondary mud collection. During this process, the height of the bottom opening of the outer sleeve 4 is precisely controlled to be lower than the top surface of the sludge collecting tank 10 but higher than the liquid level in the sludge well 3, which not only prevents lake water from flowing back into the outer sleeve 4 through the opening, but also maintains the pressure gradient required for sludge flow. This solution forms a pressure difference driving mechanism by actively regulating the spatial position of the outer sleeve 4, so that the sludge flows in a directional manner under the action of hydrostatic pressure, significantly improving the stability and sustainability of secondary sludge collection. In addition, in the prior art, the sludge well 3 is directly connected to the external environment, which easily causes lake water to mix with the sludge during operation. However, this solution effectively blocks the intrusion of external water bodies through height control, avoiding the problem of increased water content. Through the above technical solution, the present application solves the problem that external sludge cannot effectively flow into the sludge well 3 during the secondary sludge collection process, and achieves continuous and efficient sludge collection by establishing a sludge flow path driven by pressure difference. At the same time, the solution blocks the mixing of lake water and sludge through spatial height control, ensuring that the cleared sludge maintains a low water content state, providing basic conditions for subsequent resource utilization.

[0073] Furthermore, during the lifting process of the outer sleeve 4, if silt is detected flowing into the low-lying area 101 and the silt well 3 along with the lake water, the outer sleeve 4 is immediately lowered to prevent water ingress. The lifting process of the outer sleeve 4 refers to the phase in which the vertical position of the outer sleeve 4 is adjusted by the lifting device after the pumping operation is completed. Specifically, height adjustment can be achieved using a hydraulic lifting system or a winch, while the stability of the sleeve is maintained by controlling the lifting speed. This operation phase must be linked to the silt flow state.

[0074] Among them, when it is found that silt flows into the low-lying area 101 and the silt well 3 along with the lake water, it means that the fluid state of the connection area between the silt well 3 and the outer sleeve 4 is detected in real time through a monitoring device or manual observation. Specifically, a turbidity sensor or an underwater camera can be used to realize turbidity monitoring, and a response mechanism is triggered when it is detected that the concentration of suspended matter in the water body exceeds the threshold. This monitoring link is used to determine whether the external water body has broken through the isolation barrier. Among them, immediately lowering the height of the outer sleeve 4 means that after the abnormal flow is detected, the cylinder is lowered to a predetermined position within a set time by the actuator. Specifically, a lifting device can be used to achieve rapid response, and the lowering distance can be dynamically adjusted according to the height of the mud surface. This action restores the physical barrier function by rebuilding the contact surface between the bottom of the cylinder and the silt layer. Through the above technical solution, the present application effectively blocks the reverse infiltration of external pollutants to the mud collection area during dredging operations, ensuring the stable storage of collected silt. This technology is particularly effective in the final stage of dredging. When the outer silt layer becomes thinner, the height of the isolation device is dynamically adjusted to avoid mud-water mixing caused by hydrostatic pressure imbalance, thereby ensuring the low water content of the cleared silt and creating favorable conditions for subsequent resource utilization.

[0075] In a specific scheme, this method uses a working platform floating on the water surface and a lifting device mounted thereon to perform the following operations: the outer sleeve 4 is lowered vertically to above the low-lying area 101 of the mud collecting tank 10 by the lifting device; the water pump 5 is hoisted into the outer sleeve 4 by the lifting device to pump water; the grab bucket 6 is controlled by the lifting device to remove the silt; and the outer sleeve 4 is lifted by the lifting device.

[0076] Among them, the working platform refers to a floating carrier that carries the dredging equipment. Specifically, it can be implemented by a steel platform with a pontoon structure. Its floating characteristics can adapt to the working requirements of different water depths. The lifting device refers to a mechanical arm with a multi-directional lifting function. Specifically, it can be implemented by a hydraulically driven rotary crane. It is used to accurately control the spatial positioning of the outer sleeve 4, the water pump 5 and the grab 6. The water pump 5 refers to a device used to discharge the water in the outer sleeve 4. Specifically, it can be implemented by a submersible pump. By being directly arranged above the silt well 3, rapid dehydration is achieved. The grab 6 refers to a mechanical device for grabbing silt. Specifically, it can be implemented by a hydraulic grab 6. Its opening and closing action is remotely controlled by the lifting device to complete the silt removal in the silt collecting tank 10. Specifically, the working platform moves along the water surface as a mobile workstation to the working area of the silt collecting tank 10. The lifting device lowers the outer sleeve 4 vertically to a position that completely covers the silt well 3, ensuring that the lower end of the cylinder is immersed in the silt to form a sealed space. A pump 5 is lowered into the outer sleeve 4 via a lifting device, directly extracting water from the sleeve to accelerate sludge settling and dehydration. Once dehydration is complete, the pump 5 can be quickly removed to avoid interfering with subsequent silt removal. A grab bucket 6, controlled by the lifting device, enters the sludge collection trough 10 to grab the dehydrated sludge, achieving simultaneous mechanical sludge extraction and hydrostatic sludge collection. The lifting device adjusts the height of the outer sleeve 4 based on the water level in the sludge well 3, maintaining a hydrostatic pressure differential to encourage continuous inflow of sludge.

[0077] In such Figure 6-8 In the preferred embodiment shown, this embodiment further proposes to use the above-mentioned secondary mud collection and dredging method in the river confluence area; specifically

[0078] Step (1) includes the following sub-steps:

[0079] Step (1.1): select the river channel in the lake as the desilting area, construct a sludge collecting trough 10 at the bottom of the desilting area, and extend downward from the center of the low-lying part 101 of the sludge collecting trough 10 to construct a sludge well 3;

[0080] Step (1.2): a permeable sediment trap 7 is provided at the rear side of the sediment collecting trough 10 in the direction of the river confluence.

[0081] The river confluence refers to a specific area within a lake that receives river flow. Because this area carries a large amount of sediment, it is suitable for dredging. This can be achieved by determining the main flow path of the river through hydrological surveys, leveraging the natural flow dynamics to improve silt collection efficiency. The sediment trap 7 is a permeable barrier located behind the silt collection trough 10. Specifically, it can be implemented using a permeable net suspended by floats and anchored with fixed piles. This allows water to pass through but blocks the spread of sediment, preventing the collected silt from being redispersed.

[0082] Specifically, after selecting the dredging area at the river confluence, a mud collecting trough 10 is first constructed at the bottom by mechanical or hydraulic means, and a mud well 3 is formed downward from the low-lying part 101 in the trough, forming a directional mud collection channel. Subsequently, a permeable sand-trapping device 7 is arranged at the rear side of the mud collecting trough 10. The enclosure is composed of floats, a permeable net and fixed piles. The lower end of the permeable net extends to near the surface of the lake bed, allowing water to flow through to maintain water exchange and intercepting upstream sand to avoid secondary diffusion. When the mud and sand carried by the river flow enters the mud collecting trough 10, it naturally settles to the low-lying part 101 in the trough due to the reduction in flow rate. After some fine-grained mud penetrates the mud collecting trough 10 with the water flow, it is blocked by the sand-trapping device 7 and settles in the rear area of the trough, achieving a synergistic effect of efficient mud collection and diffusion prevention. This solution proactively selects high-sediment-load areas to construct a sediment collection structure and adds a permeable sediment interception device 7. This not only utilizes the natural dynamics of water flow to enhance sediment collection, but also reduces sediment diffusion through physical barriers, resolving the conflicting issues of low efficiency and ecological disturbance in traditional technologies. Through the above-mentioned technical solution, this application can significantly improve the efficiency of silt collection in the river confluence area, while effectively controlling the secondary pollution of the water body caused by sediment diffusion during operation. The permeable enclosure structure maintains the smooth flow of water, avoids the flow turbulence caused by complete interception, and creates favorable conditions for subsequent silt dehydration and resource utilization.

[0083] In a specific solution, the sludge collecting trough 10 is constructed as a linear trough and its extension direction intersects with the direction of the river confluence, and the setting direction of the sand-trapping device 7 is consistent with the extension direction of the sludge collecting trough 10. Among them, the linear trough refers to a trough-like structure with a clear extension direction, which can be realized by mechanical excavation or prefabricated component splicing. Its extension direction forms an intersection angle with the river flow, and the interception range of silt is expanded through spatial layout. Among them, the sludge-trapping device 7 refers to a permeable barrier structure, which can be realized by a float-suspended permeable net and anchored with fixed piles. Its extension direction is consistent with the direction of the sludge collecting trough 10, and the silt not captured by the sludge collecting trough 10 is blocked from spreading through a continuous barrier. Specifically, the extension direction of the linear trough forms an intersection angle with the direction of the water flow converging into the river, such as an orthogonal or acute angle arrangement, so that the silt carried by the water flow is accelerated to settle when entering the sludge collecting trough 10 due to the change in flow direction. At the same time, the sand-trapping device 7 is arranged parallel to the length of the mud collecting trough 10, forming a secondary interception belt complementary to the mud collecting trough 10, and performing secondary interception on the fine-grained mud that bypasses the mud collecting trough 10. This spatial layout achieves dual interception of mud in the horizontal and vertical directions through the synergistic effect of the mud collecting trough 10 and the sand-trapping device 7. Through the above technical solution, the present application can improve the interception efficiency of mud in the water flow entering the river channel, reduce the diffusion range of mud in the lake, thereby reducing the risk of repeated pollution of the surrounding waters during dredging operations, and at the same time increase the amount of mud collected per unit time.

[0084] exist Figure 8In the specific scheme shown, the sediment interception device 7 includes multiple floats 71 floating on the water surface at the river confluence, a permeable net 72 with its upper end fixed to the floats 71 and its lower end below the water surface, and fixed piles 73 that secure the floats 71 and permeable net 72 to the lakebed. The floats 71 are buoyant floating units, specifically hollow polyethylene buoys. The buoyancy supports the permeable net 72 and automatically adjusts its vertical position as the water level changes. The permeable net 72 is a flexible filter material with a porous structure, specifically a nylon woven mesh. The pore size is set according to the target intercepted sediment particle size, forming a physical barrier that is permeable to water flow. The fixed piles 73 are anchoring members inserted vertically into the lakebed, specifically steel piles. The friction between the piles and the lakebed maintains the spatial stability of the floats 71 and permeable net 72. Specifically, the floats 71 form a continuous floating belt on the water surface, driving the permeable net 72 to remain vertically suspended. When the river water level fluctuates, floats 71 drive the permeable net 72 to rise and fall synchronously, ensuring that the lower end of the permeable net 72 remains below the water surface in an effective interception zone. The permeable net 72 extends from the water surface to near the lakebed, forming a filter layer covering the entire water depth, allowing water to pass through while retaining suspended sediment. Piles 73 anchor the floats 71 and permeable net 72 together, preventing structural deflection caused by water impact. The bottom of the permeable net 72 lies close to the lakebed, eliminating the escape path for sediment caused by the gap between the bottom of traditional enclosures and the lakebed, and intercepting high-concentration sediment-laden water near the bottom. In some embodiments, the spacing between floats 71 can be set to 3-5 meters, the distance between the bottom of the permeable net 72 and the lakebed surface is controlled within 10 centimeters, and the piles 73 can be buried to a depth of more than 2 meters. The porosity of the permeable net 72 can be set to 60%-70%, ensuring water flow while retaining sediment particles larger than 0.1 mm. Through the above-mentioned technical solution, the present application solves the problem of interception failure caused by water level fluctuations in traditional sediment interception device 7, eliminates the escape path of bottom sediment, and improves sediment interception efficiency. The synergistic effect of permeable net 72, float 71, and fixed pile 73 maintains the water exchange capacity while achieving targeted sediment enrichment, creating stable preconditions for efficient sediment collection in subsequent sediment collection trough 10 and reducing the risk of secondary pollution.

[0085] exist Figure 9 In the specific embodiment shown, the sand trap device 7 includes: a permeable net 72 below the water surface; and fixed piles 73 for fixing the permeable net 72 on the lake bed. The permeable net 72 in this solution is used to intercept the size of sediment particles and form a physical barrier that can be penetrated by water flow. This is similar to the above-mentioned recorded solution and will not be repeated here. Figure 8 The embodiment shown eliminates the float 71, thereby reducing the impact of the estuary water flow on the sand-trapping device 7 and making it more stable.

[0086] Furthermore, the bottom of the permeable net 72 extends close to the lakebed surface. Close to the lakebed surface means that the bottom of the permeable net 72 maintains non-rigid contact with the lakebed surface. This can be achieved by suspending a counterweight or embedding a flexible ballast strip at the bottom of the permeable net 72, allowing the net to naturally hang down to a position less than 10 centimeters from the lakebed surface. This design minimizes the escape space for bottom sediment without damaging the surface ecology of the lakebed. Specifically, the permeable net 72 extends downward from the surface float 71 to near the lakebed surface, forming a continuous interception zone from the water surface to the near-surface of the lakebed. When river water carries sediment into the lake, the permeable net 72 filters the water through its porous structure, trapping the suspended sediment carried by the water on the water-facing side of the net. Because the bottom of the permeable net 72 is close to the lakebed surface, bottom-loaded sediment that might otherwise escape through the gaps at the bottom of a traditional enclosure is physically blocked. However, the water can still slowly seep through the mesh, preventing the formation of local vortices behind the enclosure. At the same time, the flexible contact between the permeable net 72 and the lakebed surface avoids the destruction of benthic habitats caused by the insertion of a rigid structure into the lakebed, and maintains the natural state of the bottom sediments.

[0087] In summary, the secondary sludge collection and desilting method proposed in this plan has the following significant advantages, which are summarized as follows:

[0088] 1. Simultaneous operation of mud scraping and mud collection: The adjustable outer sleeve 4 realizes the spatial separation and temporal overlap of mud collection and dredging, breaking through the limitation of traditional methods that require the sequential execution of mud scraping and mud collection, significantly shortening the project cycle and reducing time costs.

[0089] 2. Actively drive the secondary flow of silt: Utilize the hydrostatic pressure difference to build a dynamic silt collection and desilting circulation system, so that the peripheral silt continuously flows into the silt well 3, forming an active recharge mechanism and solving the problem of low collection rate of traditional technology.

[0090] 3. Physical dehydration to reduce moisture content: The pumping operation in the closed space of the outer sleeve 4 promotes the natural dehydration of the sludge, reducing the need for subsequent chemical treatment. The cleared sludge can be directly used in farmland and gardens to achieve resource utilization.

[0091] 4. Closed operation reduces secondary pollution: The closed operation of the outer sleeve 4 avoids water disturbance and diffusion of suspended matter during dredging, protects the water ecological environment, and solves the problem that traditional open operation easily causes water turbidity.

[0092] 5. Dynamic circulation improves treatment efficiency: By alternating closed silt removal and open silt collection, combined with dynamic adjustment of the height of the outer sleeve 4, a continuous silt collection-silt removal cycle is formed, significantly increasing the silt treatment volume per unit time.

[0093] 6. Directional optimization of river confluences: Construct linear sediment collection troughs 10 and install permeable sediment interception devices 7 at the confluence area of the river. This utilizes the natural dynamics of water flow to improve sediment collection efficiency while reducing sediment diffusion through physical barriers, thus solving the problem of dredging in areas with high sediment loads.

[0094] 7. Eco-friendly permeable enclosure design: The permeable net 72 works in conjunction with the float 71 and fixed piles 73 to intercept sediment and maintain water exchange, avoiding the ecological damage caused by traditional rigid enclosures. The bottom is close to the lakebed and eliminates the escape path of sediment.

[0095] Through systematic innovation, this plan comprehensively optimizes the operation mode, structural design and ecological protection, significantly improving the dredging efficiency and resource utilization level, and is both technologically advanced and environmentally friendly.

[0096] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0097] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention.

Claims

1. A method for collecting and removing contaminated sediment based on landform transformation, characterized in that: The following steps are involved: Step (1), constructing a mud collecting trough (10) at the bottom of the lake desilting area, and extending downward from the center of a low-lying area (101) of the mud collecting trough (10) to construct a mud well (3); Step (2), collecting the surrounding sludge into the low-lying area (101) of the sludge collecting tank (10) and the sludge well (3) through a sludge scraping device; Step (3), vertically lowering the outer sleeve (4) to above the low-lying area (101) of the mud collecting trough (10), so that the outer sleeve (4) completely covers the mud well (3) and the lower end of the sleeve is sunken into the mud in the low-lying area (101), and the upper end of the sleeve is exposed to the water surface; Step (4), removing the water inside the outer sleeve (4); Step (5), removing the silt collected in the outer sleeve (4) and the silt well (3); Step (6), collecting the surrounding sludge into the sludge collecting tank (10) outside the outer sleeve (4) by gravity gathering and / or scraping equipment; Step (7), lifting the outer sleeve (4) until the bottom opening thereof is lower than the mud surface height of the low-lying area (101), and the external mud flows into the mud well (3) under the action of hydrostatic pressure to form secondary mud collection; Step (8), repeating steps (5)-(7) to remove the secondary collected sludge until the sludge is completely cleared; The operations of step (5) and step (6) can be performed step by step or simultaneously.

2. The method for collecting and removing contaminated sediment based on landform modification according to claim 1, characterized in that: The diameter of the outer sleeve (4) is larger than the diameter of the sludge well (3) and smaller than the maximum diameter of the low-lying area (101) in the sludge collecting trough (10).

3. The method for collecting and removing contaminated sediment based on landform modification according to claim 1 is characterized in that: A rigid cylinder is pre-buried in the sludge well (3).

4. The method for collecting and removing contaminated sediment based on landform modification according to claim 1 is characterized in that: In step (7), the outer sleeve (4) is lifted until the height of its bottom opening is lower than the height of the top surface of the mud collecting trough (10) at the edge of the low-lying area (101).

5. The method for collecting and removing contaminated sediment based on landform modification according to claim 1 is characterized in that: In step (7), during the process of lifting the outer sleeve (4), when it is found that silt flows into the low-lying area (101) and the silt well (3) along with the lake water, the height of the outer sleeve (4) is immediately lowered to prevent water from entering.

6. The method for collecting and removing contaminated sediment based on landform modification according to claim 1 is characterized in that: The following operations are performed using a working platform (1) floating on the water surface and a lifting device (2) mounted thereon: - In step (3): the outer sleeve (4) is lowered vertically to above the low-lying area (101) of the mud collecting trough (10) by means of the lifting device (2); - In step (4): using the lifting device (2) to lower the water pump (5) into the outer sleeve (4) to pump water; - In step (5): the grab bucket (6) is operated by the lifting device (2) to remove the silt; - In step (7): the outer sleeve (4) is lifted by the lifting device (2).

7. A method for collecting and removing contaminated sediment based on landform modification according to any one of claims 1 to 6, characterized in that: Step (1) includes the following sub-steps: Step (1.1), selecting the river channel in the lake as the desilting area, constructing a sludge collecting trough (10) at the bottom of the desilting area, and extending downward from the center of the low-lying part (101) of the sludge collecting trough (10) to construct a sludge well (3); Step (1.2): a permeable sediment trap (7) is provided at the rear side of the sediment collecting trough (10) in the direction of the river confluence.

8. The method for collecting and removing contaminated sediment based on landform modification according to claim 7 is characterized in that: The mud collecting trough (10) is constructed as a linear trough, and its extension direction intersects with the direction of confluence of the river channel; The arrangement direction of the sand trapping device (7) is consistent with the extension direction of the mud collecting trough (10).

9. The method for collecting and removing contaminated sediment based on landform modification according to claim 7, characterized in that: The sand-trapping device (7) comprises: - a plurality of floats (71) floating on the water surface at the confluence of the river; - a permeable net (72) with its upper end fixed to the float (71) and its lower end below the water surface; - Fixing piles (73) for fixing the float (71) and the permeable net (72) to the lake bed.

10. The method for collecting and removing contaminated sediment based on landform modification according to claim 7, characterized in that: The sand-trapping device (7) comprises: - a permeable net (72) below the water surface; - Fixing piles (73) for fixing the permeable net (72) to the lake bed.

11. The method for collecting and removing contaminated sediment based on landform modification according to claim 9 or 10, characterized in that: The bottom of the permeable net (72) extends to a position close to the surface of the lake bed.

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