Excavation method for soil between piles of wharf

Abstract

The invention relates to the technical field of wharf construction, in particular to an excavation method for inter-pile soil of a wharf, segmental excavation is performed in the length direction of the wharf, the excavation area on the cross section of each segment is divided into a first area and a second area, the first area is located above the water level, and the second area is located above the water level; the second area is located below the water level and above the bank slope. The method comprises the following steps that land excavation equipment is used for excavating the first area; the second area is excavated through the side, facing the water area, of the front edge line of the wharf by using overwater excavation equipment; and residual soil at the bottom of the second area is cleaned through mud suction equipment, and excavation of the soil between the piles of the wharf is completed. Through coordination and cooperation of the land excavation equipment, the water excavation equipment and the mud suction equipment, excavation of the soil between the piles of the wharf is achieved, and the problem that the soil between the pile foundations of the wharf cannot be effectively excavated through a traditional grab dredger is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of wharf construction, and particularly relates to a method for excavating soil between wharf piles. Background Art

[0002] In traditional wharf construction techniques, the general steps are to first excavate and shape the bank slope, then construct a pile foundation in this area, and gradually build the upper structure of the wharf based on this. However, when faced with areas of wharves to be built where there is already a large amount of backfill soil and the terrain is higher than the water level, the applicant has newly developed a reverse construction method for wharves, and this technology will be patented separately.

[0003] This method breaks the routine. Instead of pre-excavating and shaping the bank slope, it makes full use of the existing land environment in the area of the wharf to be constructed, and first constructs the pile foundation and pile cap. After this step is completed, the earthwork excavation between the piles is carried out. However, this new technical process faces a significant technical problem: Since the pile cap and pile foundation have been completed before excavating the bank slope, the presence of the pile cap and pile foundation severely restricts the effective excavation of the bank slope by traditional water grab ships. Specifically, the grab ship cannot enter the area of the pile foundation, and at the same time, the grab of the grab ship is extremely inconvenient to operate between the piles, resulting in the inability to effectively excavate the soil between the piles. Therefore, there is an urgent need to develop a solution for excavating the soil between the piles to overcome the problem that the traditional grab ship cannot effectively excavate the soil between the wharf piles. Summary of the Invention

[0004] The purpose of the present invention is to overcome the problem in the prior art that the traditional grab ship cannot effectively excavate the soil between the wharf piles, and to provide a method for excavating the soil between the wharf piles.

[0005] The present invention provides a method for excavating the soil between the wharf piles. Along the length direction of the wharf, sectional excavation is carried out. On the cross-section of each section, the excavation area is divided into a first area and a second area. The first area is above the water level line, and the second area is below the water level line and above the bank slope, including the following steps: S1: Use onshore excavation equipment to excavate the first area; S2: Use offshore excavation equipment on the side of the wharf front line facing the water area to excavate the second area; S3: Use a dredging device to clean the residual soil at the bottom of the second area to complete the excavation of the soil between the wharf piles.

[0006] The water level line is the designed water level line, which is generally the average water level of the wharf during construction.

[0007] The quay front line refers to the demarcation line between the water area and the quay pile foundation. Specifically, the demarcation line is located on the surface of the outermost pile cap facing the water area, that is, the side of the pile cap farthest from the land area facing the water area.

[0008] The present invention provides a method for excavating the soil between the quay piles. Since the first area is above the water level line, the onshore excavation equipment can be directly used for excavation. Compared with the underwater excavation method, this excavation method not only has high excavation efficiency, but also because the onshore excavation equipment can be directly moved between the pile foundations for excavation operations, it solves the defect that the traditional underwater excavation cannot enter between the pile foundations due to the large volume of the equipment, and at the same time avoids the danger that the excavation equipment may collide with the pile foundations or squeeze the pile foundations due to improper operation during traditional underwater excavation.

[0009] The underwater excavation equipment is used to excavate the second area, and the underwater excavation equipment only operates on the side of the quay front line facing the water area. The second area is divided into two inner and outer areas by the quay front line. The area on the side of the quay front line facing the water area is the outer area, and the area on the side of the quay front line facing the land area is the inner area. Since the outer area of the second area is located in the water area and is not affected by pile foundations and pile caps, the underwater excavation equipment can be used for earth excavation. The soil on the water side of the inner area of the second area is supported by the soil in the outer area. After the soil in the outer area is excavated, the soil on the water side of the inner area lacks the necessary lateral support. Therefore, under the action of gravity, the soil in the inner area will slide towards the outer area, and then continue to be excavated by the underwater excavation equipment, so as to complete the excavation operation of the second area. By this method, there is no need to move the underwater excavation equipment to the pile foundation area for excavation operations, so the influence of pile foundations and pile caps on the excavation operations can be reduced.

[0010] After using the underwater excavation equipment to excavate the second area, there will be some residual soil left at the bottom of the second area, that is, the area between the pile foundations and the area above the slope of the bank. The residual soil cannot automatically slide towards the outer area of the second area due to the action of gravity. Therefore, it is necessary to use the dredging equipment to clean the residual soil. The specific operation is to remove the residual soil through the suction function of the dredging equipment.

[0011] Through the coordinated cooperation of the onshore excavation equipment, the underwater excavation equipment and the dredging equipment, the excavation of the soil between the quay piles is realized, and the problem that the traditional grab dredger cannot effectively excavate the soil between the quay pile foundations is solved.

[0012] The onshore excavation equipment may be a loader, a general excavator, a long-arm excavator, etc. The width of the onshore excavation equipment needs to be less than the spacing between two adjacent rows of the pile foundations, so that the onshore excavation equipment can move between the pile foundations.

[0013] The offshore excavation equipment may be a bucket ladder dredger or a grab dredger. The bucket ladder dredger excavates sediment from the bottom of the water and lifts it onto the ship through the continuous movement of a series of bucket chains on the ladder boom. The grab dredger grabs the sediment at the bottom of the water through a grab on a crane.

[0014] The mud suction equipment may be a pump suction dredger installed on land or a suction dredger that can move on water.

[0015] When using the onshore excavation equipment to excavate the first area, it can be excavated from the side close to the water area to the side close to the land area, or from the side close to the land area to the side close to the water area.

[0016] Preferably, in step S1, when excavating the first area, the excavation method is to excavate from the side close to the water area to the side close to the land area. When excavating the first area from the side close to the water area to the side close to the land area, the unexcavated area can be used as a transportation channel for the earthmoving trucks, which can reduce the moving distance of the onshore excavation equipment and further improve the excavation efficiency of the first area. When excavating the first area, it can be excavated to the water level elevation at one time or in multiple layers. When the difference between the original elevation of the first area and the water level elevation is less than or equal to 2m, it can be chosen to excavate to the water level elevation at one time. When the difference between the original elevation of the first area and the water level elevation is greater than 2m, it can be chosen to excavate to the water level elevation in multiple layers.

[0017] Preferably, in step S2, when using the offshore excavation equipment to excavate the second area, it is excavated in layers from the quay front line towards the water area, and the layer height is less than or equal to 2m. The reason for adopting this layered excavation method is mainly to avoid the excessive height difference formed between the soil mass in the inner area and the outer area in the second area. This excessive height difference will cause the soil mass in the inner area of the second area to exert an excessive lateral pressure on the pile foundations, and the excessive lateral pressure may pose a threat to the structural safety of the pile foundations, thus there is a risk of causing pile breakage accidents. Therefore, it is necessary to carry out layered excavation and control the layer height below 2m.

[0018] When excavating each layer of the second area, excavation is carried out from the quay front line towards the water area. The purpose is to form a height difference on the water-side of the soil between the piles as early as possible, so that the soil between the piles slides towards the water-side of the quay front line under the action of gravity. At the same time, the above-water excavation equipment continues to excavate towards the water area at the current excavation layer, so as to shorten the time required for the soil between the piles to slide to the water-side of the quay front line, thereby improving the efficiency of the overall construction excavation.

[0019] Preferably, in step S2, when excavating each layer, the following steps are included: S21: Excavate the soil on the water-side of the quay front line in the second area; S22: Use the underwater agitation method or the water flow impact method to promote the soil on the land-side of the quay front line in the second area to slide towards the water-side of the quay front line; S23: Excavate the soil that has slid to the water-side of the quay front line in step S22 to complete the excavation work of the current layer.

[0020] The purpose of this solution is that when the soil on the land-side of the quay front line in the second area cannot slide towards the water-side of the quay front line by its own weight in a short time, the underwater agitation method or the water flow impact method is used to promote the soil on the land-side of the quay front line in the second area, that is, the soil between the piles, to slide more quickly to the water-side of the quay front line. Because there is no influence of pile foundations and pile caps on the water-side of the quay front line, the above-water excavation equipment can be used to excavate the soil that has slid to the water-side of the quay front line. This solution further improves the efficiency of the excavation operation.

[0021] The underwater agitation method can be realized by a submersible mixer. The submersible mixer drives the impeller to rotate through an electric motor, and this rotational movement can cause the vibration of the soil between the piles, thereby promoting the soil between the piles to slide along the slope.

[0022] The water flow impact method can be realized by a high-pressure water pump. The high-pressure water pump impacts the soil between the piles underwater, thereby promoting the soil between the piles to slide along the slope.

[0023] Preferably, in the step S22, it further includes controlling the slope of the slope formed after the earthwork on the landward side of the quay front line in the second area to be less than or equal to the slope of the bank slope. The purpose of this solution is to control the slope of the slope within a safe range to prevent excessive lateral pressure on the pile foundation due to too large a slope of the slope, thereby threatening the structural safety of the pile foundation. Since the slope of the bank slope is designed according to safety standards, ensuring that the slope of the slope does not exceed the slope of the bank slope is a safe and feasible practice.

[0024] Preferably, in the step S3, when using the dredging equipment to clean the residual soil at the bottom of the second area, it is cleaned from top to bottom along the slope of the bank slope. The advantage of this method is that by moving the dredging equipment from the top to the bottom along the slope, the cleaning task can be completed efficiently at one time. In contrast, if the method of cleaning from the bottom to the top of the slope is selected, the problem that the soil body at the cleaned part slides down along the slope may be encountered, which may cause the dredging equipment to need to make multiple round trips for cleaning, increasing the work complexity and time cost.

[0025] Preferably, when the segment adjacent to the current segment is the segment to be excavated, a slope operation needs to be carried out at one end of the current segment close to the segment to be excavated, and the slope of the slope is controlled below 0.5. This solution can effectively avoid the lateral soil pressure effect of the segment to be excavated on the pile foundation of the current segment, thereby protecting the structural safety of the pile foundation. The slope operation can gradually reduce the height of the earthwork, form a gradually transitional inclined plane, which can more effectively disperse the soil pressure, reduce the possibility of its concentrated action on the pile foundation, and thus reduce the risk of damage to the pile foundation due to the lateral soil pressure effect, ensuring the safety and stability of the structure.

[0026] Preferably, in the step S1, the onshore excavation equipment is a long-arm excavator, and the onshore excavation equipment maintains a distance of at least 50 cm from both the pile foundation and the pile cap. The long-arm excavator has significant advantages in high construction efficiency, strong adaptability, and flexible operation compared with ordinary excavators. With its unique long-arm structure, the long-arm excavator can expand the operation range and cover a wider excavation area, thereby reducing the need for the excavator itself to move. In addition, the long-arm structure further increases the excavation depth of the excavator. The onshore excavation equipment maintains a distance of at least 50 cm from both the pile foundation and the pile cap. The purpose of this solution is to reduce the risk of accidental collision between the long-arm excavator and the pile foundation or the pile cap and avoid damage to the pile foundation.

[0027] Preferably, in the step S2, the water excavation equipment is a grab dredger. Compared with a bucket ladder dredger, the grab dredger is relatively simple to operate and has relatively low skill requirements for operators, which helps to reduce labor costs and improve operation efficiency. At the same time, the grab dredger can also provide better construction accuracy when precisely controlling the excavation range and depth.

[0028] Preferably, in the step S3, the mud suction equipment is a suction dredger, and the suction dredger includes an open barge, a sand pump, and a mud suction pipe head, including the following steps: S31: Lower the mud suction pipe head into the water; S32: Start the mud suction operation, suck the residual soil into the open barge. During the mud suction process, the mud suction pipe head moves downward along an S-shaped path on the slope of the bank slope to complete the mud suction operation.

[0029] Compared with a pump suction dredger installed on land, the suction dredger can move on the water surface, has higher convenience and flexibility, and can further improve the construction efficiency of cleaning the residual soil. The suction dredger can suck the residual soil through a pipeline to a specific area on land or suck it onto the ship for temporary storage. The sand pump has the function of directly extracting the residual soil from the second area and transporting it into the open barge. Once the open barge is full of the residual soil, it can sail through the waterway to the designated dumping area and quickly perform the unloading operation, which significantly improves the efficiency of construction operations.

[0030] Compared with the prior art, the beneficial effects of the present invention are: The present invention provides a method for excavating the soil between the piles of a wharf. Through the coordinated cooperation of the onshore excavation equipment, the water excavation equipment, and the mud suction equipment, the excavation of the soil between the piles of the wharf is realized, and the problem that the traditional grab ship cannot effectively excavate the soil between the wharf piles is solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the excavation of the first area in the present invention.

[0032] Figure 2 It is a schematic diagram of the layered excavation of the second area in the present invention.

[0033] Figure 3 It is a schematic diagram of the cleaning of the residual soil in the second area in the present invention.

[0034] Figure 4 It is a schematic diagram of the wharf after the excavation is completed in the present invention.

[0035] Figure 5 It is a finite element modeling diagram of the layered excavation of the second area in the present invention.

[0036] Figure 6 It is the displacement nephogram of the finite element simulation result of the layered excavation in the second area of the present invention.

[0037] Markings in the figure: 1 - bank slope, 101 - slope surface, 2 - first area, 3 - second area, 301 - layered excavation line, 4 - quay front line, 5 - pile foundation, 6 - pile cap, 7 - onshore excavation equipment, 8 - offshore excavation equipment, 9 - dredging equipment, 10 - water level line, 11 - residual soil. Specific implementation manners

[0038] The present invention will be further described in detail below in conjunction with specific embodiments. However, this should not be construed as limiting the scope of the above-mentioned subject matter of the present invention to the following embodiments. All technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0039] In the description of the specific embodiments of the present invention, without special explanation, the expression terms of the orientation or position relationship such as "upper", "lower", "left", "right", "center", "inner", "outer", etc. are all based on the orientation or position relationship shown in the drawings, or the orientation or position relationship when the invention product / device / equipment is commonly used. These orientation or position relationship terms are only for the convenience of describing the present invention solution or simplifying the description in the specific embodiments, facilitating technicians to quickly understand the solution, rather than indicating or implying that a specific device / component / element must have a specific orientation, or be constructed and operated in a specific position relationship. Therefore, it should not be construed as a limitation to the present invention.

[0040] In addition, when terms such as "horizontal", "vertical", "hanging", "parallel" appear, it does not mean that the corresponding device / component / element is required to be absolutely horizontal or vertical or hanging or parallel, but it can be slightly inclined or deviated. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and it does not mean that the structure must be completely horizontal, but it can be slightly inclined. Or, it can be simply understood that the corresponding device / component / element is arranged in directions such as "horizontal", "vertical", "hanging", "parallel", etc., and can have an error / deviation of ±10% relative to the corresponding direction setting, more preferably an error / deviation within ±8%, more preferably an error / deviation within ±6%, more preferably an error / deviation within ±5%, more preferably an error / deviation within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still perform its function in the solution of the present invention.

[0041] In addition, when expressions such as "first", "second", "third", etc. appear in the terms, they are only used to distinguish the description of the same or similar components, and should not be understood as emphasizing or implying the relative importance of specific components.

[0042] In addition, in the description of the embodiments of the present invention, "several", "multiple", "a number of" represent at least 2. It can be any situation such as 2, 3, 4, 5, 6, 7, 8, 9, etc., and even can be a situation of more than 9.

[0043] In addition, in the description of the technical solution of the present invention, unless otherwise clearly specified / defined / restricted, when terms such as "set", "installed", "connected", "connected", "provided with", "laid", "arranged" appear, they should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection. It can be connection means commonly used in the art such as welding, riveting, bolting, threaded connection, etc. This kind of connection can be a mechanical connection, an electrical connection or a communication connection; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two components.

[0044] Embodiment 1 As Figure 1 shown, a method for excavating the soil between the wharf piles is to perform sectional excavation along the length direction of the wharf. On the cross-section of each said section, the excavation area is divided into a first area 2 and a second area 3. The first area 2 is above the water level line 10, the second area 3 is below the water level line 10, and the second area 3 is above the bank slope 1, including the following steps: S1: Use the onshore excavation equipment 7 to excavate the first area 2. The excavated soil is transported to the designated spoil ground by a dump truck. As Figure 1 shown, a schematic diagram of using the onshore excavation equipment 7 to excavate the first area 2 is shown.

[0045] S2: Use the underwater excavation equipment 8 to excavate the second area 3 on the side of the quay front line 4 facing the water area. Specifically, in the second area 3, the area between the piles on the side of the quay front line 4 facing the land area is the inter-pile area, and the underwater excavation equipment 8 can only carry out excavation operations on the side of the second area 3 facing the water area of the quay front line 4. The soil on the side of the second area 3 facing the land area of the quay front line 4, that is, the soil between the pile foundations 5, will naturally collapse under the action of gravity during the excavation process due to the loss of lateral support in the water area direction, forming a slope. As Figure 2 shown, it shows a schematic diagram of using the underwater excavation equipment 8 to excavate the second area 3.

[0046] During the excavation operation, in order to accurately monitor the excavation progress, an echo sounder or a water depth sounding weight can be used to measure the excavated area. The specific method is to set a measurement point every 2 meters in both the horizontal and vertical dimensions to ensure that the excavation depth neither exceeds the expected value nor is lower than the requirement, thereby effectively avoiding the occurrence of under-excavation or over-excavation phenomena.

[0047] S3: Use the dredging equipment 9 to clean the residual soil 11 at the bottom of the second area 3 to complete the excavation of the soil between the quay piles. Specifically, after using the underwater excavation equipment 8 to excavate the second area 3, there will be residual soil 11 on the slope surface 101 of the bank slope 1. The residual soil 11 cannot slide to the side of the quay front line 4 facing the water area under the action of gravity, so it cannot be excavated by the underwater excavation equipment 8. The existence of the residual soil 11 will cause the elevation of the bank slope 1 not to meet the requirements of the design elevation. Therefore, in order to deal with this part of the residual soil 11, the dredging equipment 9 is used for cleaning operations. As Figure 3 shown, it shows a schematic diagram of using the dredging equipment 9 to clean the residual soil 11 at the bottom of the second area 3. As Figure 4 shown, it shows a schematic diagram of the shape of the slope surface 101 of the bank slope 1 after the excavation is completed.

[0048] In an optional implementation manner, in the step S1, the method of excavating the first area 2 can be to excavate from the side close to the water area to the side close to the land area. Specifically, use the land excavation equipment 7 to first excavate the soil on the side of the first area 2 close to the water area, and then gradually excavate in the direction of the land area.

[0049] In an optional implementation manner, in the step S2, when using the underwater excavation equipment 8 to excavate the second area 3, it can be excavated in layers from the quay front line 4 to the water area direction, and the layer height is less than or equal to 2m. The specific height can be 1m, 1.2m, 1.4m, 1.5m, 1.6m, 1.8m, 2m. When excavating in layers, first excavate the soil at the quay front line 4 position, and then gradually continue to excavate in the direction away from the land area. Figure 2The layered excavation lines 301 during the layered excavation of the second area 3 are shown.

[0050] In an alternative embodiment, in step S2, when excavating each layer, the following steps may be included: S21: Excavate the soil on the side of the second area 3 facing the water area along the quay front line 4.

[0051] S22: Use the underwater agitation method or the water flow impact method to cause the soil on the side of the second area 3 facing the land area along the quay front line 4 to slide towards the side of the quay front line 4 facing the water area. Specifically, a diving mixer or a high-pressure water pump can be used to flush water to agitate the soil on the side of the second area 3 facing the land area along the quay front line 4, so as to cause it to slide along the slope towards the side of the quay front line 4 facing the water area. The diving mixer or the high-pressure water pump can be used in cooperation with a small boat to facilitate transfer between different positions.

[0052] S23: Excavate the soil that has slid towards the side of the quay front line 4 facing the water area in step S22 to complete the excavation work of the current layer.

[0053] In an alternative embodiment, in step S22, it may further include controlling the slope of the slope formed after the soil on the side of the second area 3 facing the land area along the quay front line 4 slides to be less than or equal to the slope of the bank slope 1. Specifically, for example, if the slope of the bank slope 1 is 0.5, then the slope of the slope may be 0.5, 0.45, 0.4, 0.35 or 0.3.

[0054] In an alternative embodiment, in step S3, when using the dredging equipment 9 to clean the residual soil 11 at the bottom of the second area 3, it can be cleaned from top to bottom along the slope surface 101 of the bank slope 1. Specifically, the suction pipe head of the dredging equipment 9 can start from the position where the slope surface 101 intersects the water level line 10 and be cleaned down along the slope surface 101 to the bottom of the slope surface 101. The width of each cleaning along the slope surface 101 can be the spacing between two adjacent rows of pile foundations 5. For example, if the spacing between two adjacent rows of pile foundations 5 is 6.6 meters, the cleaning width can also be set to 6.6 meters. At the position where the pile foundation 5 intersects the slope surface 101, the side facing the land area is the main accumulation area of the residual soil 11, and this area needs to be cleaned as a key point.

[0055] In an alternative embodiment, when the segment adjacent to the current segment is a segment to be excavated, a slope can be made at one end of the current segment close to the segment to be excavated, and the slope of the slope is controlled below 0.5. The specific slope can be 0.5, 0.45, 0.4, 0.35 or 0.3. The length of each segment can be 40m - 60m, specifically it can be 40m, 45m, 50m, 55m, 60m.

[0056] In an alternative embodiment, in step S1, the onshore excavation equipment 7 may be a long-arm excavator. The onshore excavation equipment 7 can maintain a distance of at least 50 cm from both the pile foundation 5 and the pile cap 6. The long-arm excavator may be a crawler long-arm excavator. The width of the long-arm excavator needs to be less than the distance between the pile caps 6 of two adjacent rows of pile foundations 5 so that the long-arm excavator can operate normally between two adjacent rows of pile foundations 5. Specifically, the long-arm excavator is a model with a weight of 50 tons or more and equipped with an 18-meter long arm, and its minimum turning radius is 4 meters. The onshore excavation equipment 7 maintains a distance of at least 50 cm from both the pile foundation 5 and the pile cap 6 to avoid unnecessary damage to the pile foundation 5 or the pile cap 6 caused by the long-arm excavator. To ensure reducing damage in necessary situations, before the excavation operation, the pile cap 6 can be wrapped and protected with sponge material with a thickness of 10 cm. Similarly, when the pile body part of the pile foundation 5 is exposed, the same thickness of sponge can also be used for wrapping. Such protective measures can effectively reduce the damage caused when the long-arm excavator may accidentally collide with the pile foundation 5 or the pile cap 6.

[0057] In an alternative embodiment, in step S2, the offshore excavation equipment 8 may be a grab dredger, as Figure 2 shown. The grab dredger excavates the soil in the second area 3, transfers the excavated soil to a mud barge, and then transports the excavated soil to a designated dumping area through the mud barge. Specifically, the bucket capacity of the grab dredger can be 4 m³ - 8 m³. The capacity of the mud barge is 2000 m³ - 3000 m³. The mud barge may specifically be a self-propelled open-body mud barge, which is economical and practical and has less impact on the environment.

[0058] When using the grab dredger for layered excavation, to ensure that the accuracy of layered excavation during construction is controlled within a thickness of 2 meters per layer, clear equidistant scale marks can be set at intervals of 2 meters on the steel wire rope used by the grab of the grab dredger to guide and control the excavation depth.

[0059] In an alternative embodiment, in step S3, the mud suction equipment 9 may be a suction dredger. The suction dredger includes an open barge, a sand pumping pump, and a mud suction pipe head, and includes the following steps: S31: Move the suction dredger to the water surface of the inter-pile area, then lower the mud suction pipe head into the water and make the mud suction pipe head contact the residual soil 11.

[0060] S32: Start the mud suction operation, and suck the residual soil 11 into the open barge. During the mud suction process, the mud suction pipe head moves downward along an S-shaped path on the slope 101 of the bank slope 1 to complete the mud suction operation. Specifically, the mud suction pipe head moves downward along an S-shaped path on the slope 101 between two adjacent rows of pile foundations 5.

[0061] The open barge is composed of two symmetrical hulls (left and right or longitudinal). When loading sediment, the two hulls are in a closed state. When reaching the predetermined destination, the two hulls will be pushed apart to form a notch at the bottom. Due to the gravity of the sediment itself, it will quickly slide into the water through this notch to complete the unloading process. The sand pump is installed on the open barge. The sand pump includes a mud suction pipe and a mud suction pipe head. The mud suction pipe is used to connect the sand pump and the mud suction pipe head, and the mud suction pipe head is controlled to move in the vertical and horizontal directions through the hoisting equipment equipped on the open barge.

[0062] Specifically, the open barge uses a small open barge with a length of 18.3 m and a width of 3 m, and the sand pump uses a unit with a designed flow rate of 1000 m 3 / h - 1500 m 3 / h.

[0063] In an optional implementation, before excavation, the pile caps 6 of the pile foundations 5 in the same row can be integrally connected by an assembled channel steel steel frame to achieve the pile clamping operation on the pile caps 6 in the same row. The pile foundations 5 in the same row refer to those whose arrangement direction is perpendicular to the length direction of the wharf. Through the pile clamping operation, connecting the pile caps 6 in the same row integrally can improve the collaborative working ability between the pile foundations 5 and enhance the stability of the overall structure. During the excavation process, this integral connection can more effectively resist external loads and soil pressure, preventing the pile bodies of the pile foundations 5 from shifting, tilting or being damaged.

[0064] Embodiment 2 To evaluate the feasibility of stratified excavation of the second area 3, the key prerequisite is that during the entire excavation process, the pile top displacement of the pile foundation 5 must be strictly controlled within 150 mm specified in the design. For this purpose, the applicant adopted the finite element simulation method, selected a row of pile foundations 5 as the research object, a total of 7 pile foundations 5. Since the spacing between two adjacent rows of pile foundations 5 is 9 m, a section of soil with a width of 9 m along the longitudinal direction of the wharf was selected for simulation calculation, and the selected row of pile foundations 5 is exactly located at the center of the width of this section of soil.

[0065] The pile foundation 5 is specifically a steel pipe pile with a diameter of 1200 mm, the wall thickness of the steel pipe pile is 22 mm, the steel pipe pile material is selected as Q355B, and the pile foundation 5 uses moderately weathered siltstone as the bearing stratum.

[0066] According to different regions, the soil conditions of different positions in each region, and the case of layered excavation (each layer with a height of 2 m) in the second region 3, the soil body is divided into several finite element groups, as Figure 5 shown. According to the actual soil conditions, corresponding material models and material parameters are assigned to different finite element groups. When setting the working conditions, in accordance with the actual excavation steps, the finite element groups in the second region 3 are removed layer by layer from top to bottom to simulate the layered excavation of the second region 3. Finally, the displacement conditions of the tops of all the pile foundations 5 in the simulation results are checked. The simulation results are as Figure 6 shown. The pile top displacements of the 7 pile foundations 5 are 22 mm, 20 mm, 39 mm, 51 mm, 40 mm, 27 mm, and 23 mm from left to right respectively. The maximum pile top displacement is 51 mm, and this pile top displacement is less than the designed 150 mm. Therefore, it shows that the layered excavation of the above-mentioned solution of Embodiment 1 for the second region 3 is feasible.

[0067] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for excavating soil between wharf piles, characterized in that, Along the length of the wharf, sectional excavation is carried out. On the cross-section of each section, the excavation area is divided into a first area (2) and a second area (3). The first area (2) is above the water level line (10), and the second area (3) is below the water level line (10) and above the bank slope (1), including the following steps: S1: Use onshore excavation equipment (7) to excavate the first area (2); S2: Use offshore excavation equipment (8) on the side facing the water area along the wharf front line (4) to excavate the second area (3); S3: Use a dredging equipment (9) to clean the residual soil (11) at the bottom of the second area (3) to complete the excavation of the soil between the wharf piles.

2. The excavation method for the soil between wharf piles according to claim 1, characterized in that, In step S1, the excavation of the first area (2) is carried out from the side facing the water area to the side facing the land area.

3. The excavation method for the soil between wharf piles according to claim 1 is characterized in that, In step S2, when using the offshore excavation equipment (8) to excavate the second area (3), layered excavation is carried out from the wharf front line (4) towards the water area, and the layer height is less than or equal to 2m.

4. A method for excavating soil between wharf piles according to claim 3, characterized in that, In step S2, when carrying out excavation for each layer, the following steps are included: S21: Excavate the soil in the second area (3) on the side facing the water area along the wharf front line (4); S22: Use the underwater agitation method or the water flow impact method to prompt the soil in the second area (3) on the side facing the land area along the wharf front line (4) to slide towards the side facing the water area along the wharf front line (4); S23: Excavate the soil that has slid towards the side facing the water area along the wharf front line (4) in step S22 to complete the excavation work of the current layer.

5. A method for excavating the soil between wharf piles according to claim 4, characterized in that, In step S22, it also includes controlling the slope of the slope formed after the soil in the second area (3) on the side facing the land area along the wharf front line (4) slides to be less than or equal to the slope of the bank slope (1).

6. A method for excavating soil between wharf piles according to claim 1, characterized in that, In step S3, when using the dredging equipment (9) to clean the residual soil (11) at the bottom of the second area (3), it is cleaned from top to bottom along the slope surface (101) of the bank slope (1).

7. A method for excavating the soil between the wharf piles according to any one of claims 1-6, characterized in that When the adjacent section to the current section is a section to be excavated, slope cutting operation is carried out at one end of the current section close to the section to be excavated, and the slope of the slope cutting is controlled below 0.

5.

8. A method for excavating soil between wharf piles according to any one of claims 1-6, characterized in that, In step S1, the onshore excavation equipment (7) is a long-arm excavator, and the onshore excavation equipment (7) maintains a distance of at least 50 cm from both the pile foundation (5) and the pile cap (6).

9. A method for excavating soil between wharf piles according to claim 8, characterized in that, In step S2, the offshore excavation equipment (8) is a grab dredger.

10. A method for excavating soil between wharf piles according to claim 8, characterized in that, In step S3, the dredging equipment (9) is a dredger, and the dredger includes an open barge, a sand pumping pump, and a dredging pipe head, including the following steps: S31: Lower the dredging pipe head into the water; S32: Start the dredging operation, suck the residual soil (11) into the open barge. During the dredging process, the dredging pipe head moves along an S-shaped path from top to bottom on the slope surface (101) of the bank slope (1) to complete the dredging operation.

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