A construction method for high-piled wharves with the reverse sequence of driving piles first and then dredging mud

Abstract

The present invention relates to the technical field of port engineering, and particularly relates to a reverse construction method of driving piles first and then dredging mud for high-pile wharves, which includes the following steps: S1. Site leveling; S2. Using onshore pile driving equipment for pile foundation construction and pouring onshore pile caps; S3. Making an overall connection of the pile caps to form pile clamping; S4. Using onshore dredging equipment, in cooperation with offshore dredging equipment and mud suction equipment, to carry out mud cleaning operations between piles; S5. Laying geotextiles between piles and then carrying out stone throwing operations between piles. This method makes full use of the condition that the positions of the wharf pile foundations are basically located in the existing land area, directly driving the pile foundations in the land area environment without waiting for the dredging to be completed. This reverse construction method of "driving piles first and then dredging mud" greatly reduces the preliminary preparation time and significantly shortens the overall construction period. The pile driving in the land area has low dependence on equipment, and traditional onshore pile foundation construction equipment can be used, with lower operating costs, less maintenance and rental costs, thus effectively reducing the operation costs and operation risks.

Description

Technical Field

[0001] The present invention relates to the technical field of port engineering, and particularly relates to a reverse construction method of driving piles first and then dredging for high-piled wharves. Background Art

[0002] In the construction of offshore high-piled wharves, traditional pile foundation construction methods generally include the following steps: First, dredge the slope to the designed section elevation; then use a pile barge to carry out pile driving operations, and the pile barge is equipped with a guiding frame for a single pile to ensure positioning; after the bearing capacity of the pile foundation meets the requirements, lay geotextiles and carry out stone throwing operations; then set up a steel platform to complete the construction of the pile interior treatment, and finally pour the upper structures such as pile caps.

[0003] However, when the pile foundation position of the wharf is basically located (or entirely located) in the existing land area, the traditional method still needs to complete large-scale dredging in the land area before carrying out pile driving operations. This method relies on the waterborne pile driving process, which not only has a relatively high operation risk, but also the pile foundation construction must wait until the slope dredging is completed before it can start, resulting in a relatively late end time of the pile foundation sub-item, significantly extending the overall construction period and affecting the construction progress. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies that when the pile foundation position of the wharf is basically located in the existing land area, using the traditional pile foundation construction method for high-piled wharves affects the construction progress and has a relatively high operation risk for waterborne pile driving operations, and to provide a reverse construction method of driving piles first and then dredging for high-piled wharves.

[0005] In a first aspect, the present invention provides a reverse construction method of driving piles first and then dredging for high-piled wharves, including the following steps:

[0006] S1. Level the site;

[0007] S2. Use onshore pile driving equipment to carry out pile foundation construction and pour onshore pile caps;

[0008] S3. Make an overall connection of the pile caps to form pile clamping;

[0009] S4. Use onshore dredging equipment, in cooperation with waterborne dredging equipment and mud suction equipment, to carry out mud cleaning operations between piles;

[0010] S5. Lay geotextiles between piles and then carry out stone throwing operations between piles.

[0011] The reverse construction method of driving piles first and then dredging for high-piled wharves provided by the present invention makes full use of the condition that the pile foundation position of the wharf is basically located in the existing land area, directly driving the pile foundation in the land environment first without waiting for the dredging to be completed. This reverse construction method of "driving piles first and then dredging" greatly reduces the pre-construction preparation time and significantly shortens the overall construction period. The land-based pile driving has low dependence on equipment, and traditional onshore pile foundation construction equipment can be used, with lower operating costs, less maintenance and rental fees, thus effectively reducing the operation cost and operation risk.

[0012] To avoid the change of the pile body's stress caused by subsequent cleaning of the mud between piles and prevent the pile from tilting or shifting due to uneven stress, the present invention first integrally connects the pile caps before cleaning the mud to form pile clamping. Compared with the traditional pile clamping structure that connects the pile bodies, the pile clamping design of the present invention does not occupy the working space between piles, ensuring sufficient passage space for the mud cleaning machinery and significantly improving the efficiency and safety of subsequent mud cleaning operations.

[0013] Since the pile foundation is completed in the land environment, the subsequent mud cleaning operation between piles can first use onshore dredging equipment for cleaning, which has low equipment operation cost and high dredging efficiency; then, in cooperation with offshore dredging equipment, supplementary excavation is carried out for the sea-side area, and the suction equipment shuttles between the piles to accurately remove the residual mud, further improving the mud cleaning efficiency between piles.

[0014] Finally, after laying the geotextile between the piles and then carrying out the rock filling operation, the area between the piles is stabilized to ensure the long-term stability of the wharf foundation. By changing the construction sequence (driving piles first and then cleaning the mud) and making full use of onshore equipment and conditions, the present invention overcomes the deficiencies of the traditional method, such as long construction period, high cost, and relatively high risk of offshore pile driving operations, and provides an efficient and economical solution for similar projects.

[0015] Preferably, S1 includes the following steps:

[0016] Replace and fill the land-based silt, remove 0.2 - 0.8 m of silt, backfill and level the land-based construction platform, and backfill the construction platform at +3 m to +4 m.

[0017] There is often a silt layer in the land environment, with low and uneven bearing capacity. Direct construction may cause equipment sinking or pile foundation tilting. By removing the silt and replacing and filling it (such as filling high-bearing capacity materials such as sand and gravel), the mechanical properties of the foundation are effectively improved, providing a reliable support for the stable operation of onshore pile driving equipment; through the replacement and filling of land-based silt, the backfilling and leveling of the construction platform, and the design of widening towards the sea side, the stability of the construction platform is significantly improved, providing a solid foundation for subsequent pile foundation construction.

[0018] Preferably, S2 includes the following steps:

[0019] S21. Position the pile foundation;

[0020] S22. Measure and install the positioning frame to the designed pile position, and start driving the pile after using the crawler crane to lift the pile into position;

[0021] S23. Carry out onshore pile driving: first insert the pile with a vibratory hammer, and when the pile bottom penetrates through the sand layer, replace it with a diesel hammer to hammer the pile foundation until the designed position;

[0022] S24. Utilize an onshore piling construction platform. After excavating to the elevation of the pile cap bottom, pour a concrete cushion, install steel bars and side forms, and then conduct the pouring of the pile cap.

[0023] The installation of the positioning frame further enhances the positioning accuracy of the pile foundation. As a commonly used lifting equipment on land, the crawler crane is stable and flexible in operation, and can quickly hoist the pile to the designed position, avoiding the uncertainties brought by the swaying of the floating crane ship due to wind and waves in the traditional pile foundation construction method.

[0024] When conducting onshore piling, equipment commonly used in onshore construction such as crawler cranes, vibratory hammers, and diesel hammers are all used. Compared with the floating crane ships, pile driving boats, or special pile sinking platforms relied on in the traditional method, the procurement, leasing, and maintenance costs are lower, and there is no need for additional ship support and water transportation costs. The vibratory hammer is suitable for the initial pile insertion, reducing the disturbance to the foundation and quickly penetrating the surface layer; the diesel hammer provides a powerful impact force after the pile bottom enters the sand layer to ensure that the pile foundation reaches the designed depth. This combined method is more efficient than the traditional single hammering. Especially under onshore conditions, there is no need for underwater adjustment equipment, and the construction continuity is stronger. Compared with the traditional underwater pile sinking, onshore piling does not require ship cooperation, reducing the time for equipment switching and positioning adjustment, and significantly improving the piling efficiency.

[0025] After the pile sinking is completed, cut or splice the pile head according to the designed elevation. Immediately after completion, conduct the onshore pile cap pouring. Compared with the traditional underwater pouring, the operation is simple, the quality is easier to control, ensuring the stability of the pile cap construction and further improving the operation efficiency.

[0026] Preferably, S3 includes the following steps: After the pile cap pouring is completed, erect a fixing frame on the top of adjacent pile caps, and use a tripod to fixedly connect the pile cap and the fixing frame from the side of the pile cap to form a pile clamping.

[0027] This pile clamping structure connects individual pile caps into a whole (for example, connecting a row of pile caps), effectively dispersing external loads (such as the lateral force change of the pile body during the dredging operation or the impact of the sea - side water flow), preventing the pile foundation from tilting or shifting due to uneven stress.

[0028] The fixing frame is erected on the top of the pile cap, and the tripod is fixed from the side, avoiding the problem that the traditional pile clamping structure (such as directly connecting the pile body or supporting at the bottom) occupies the space between piles. This design ensures the smoothness of the space between piles, providing sufficient passage and operation space for the operation of onshore dredging equipment, underwater dredging equipment, and mud suction equipment during the subsequent dredging operation between piles.

[0029] Preferably, S4 includes the following steps:

[0030] S41. Build a cofferdam on the sea - side of the wharf.

[0031] S42. Use onshore dredging equipment to conduct onshore excavation in the pile foundation area. During onshore excavation, conduct layered backhoe excavation and slope setting gradually from the cofferdam towards the land area, with the excavation depth increasing gradually until the designed slope surface is reached;

[0032] S43. Taking the pile cap closest to the sea side as the demarcation line, use offshore dredging equipment to conduct layered offshore excavation gradually from the demarcation line towards the sea side, with the excavation depth increasing gradually;

[0033] After the offshore dredging equipment has excavated into a slope, alternately use the offshore dredging equipment and the mud suction equipment to remove the residual soil on the remaining slope. The offshore dredging equipment conducts layered excavation on the side facing the water area of the demarcation line, and the mud suction equipment enters between the piles to conduct layered excavation on the side facing the land area of the demarcation line until the soil cleaning work between the wharf piles is completed.

[0034] Build a cofferdam on the sea side of the wharf to effectively isolate the land area from the water area, creating a dry and stable working environment for onshore excavation. This isolation measure avoids the interference of tides, water currents or waves on the mud cleaning operation, ensuring the efficient operation of onshore dredging equipment under waterless conditions. Compared with the dredging operation completely exposed to the water area environment in traditional methods, the cofferdam significantly improves the controllability and stability of the construction, laying the foundation for the subsequent steps.

[0035] The onshore dredging equipment conducts layered backhoe excavation gradually from the cofferdam towards the land area. Compared with the traditional bulky offshore dredging equipment, it is smaller in size and more maneuverable, and can directly drive into the piles to conduct mud cleaning operations, solving the defect that traditional offshore equipment cannot enter between the piles for excavation due to its too large size; the layered backhoe excavation makes full use of the high efficiency and flexibility of onshore equipment, and the excavation depth increases gradually to form a certain slope surface, not only improving the mud cleaning efficiency, but also ensuring the stability of the excavation area, avoiding the risk of slope collapse caused by underwater soil disturbance in traditional methods;

[0036] Taking the pile cap closest to the sea side as the demarcation line, in the area on the sea side that is not blocked by the pile foundation, large offshore dredging equipment can be used for layered excavation. This targeted design gives full play to the high-efficiency operation ability of offshore equipment in a large-scale and unobstructed area, and the excavation depth increases gradually to form a stable slope surface, further improving the construction efficiency and ensuring the terrain quality. Compared with the low efficiency of relying on offshore equipment throughout the process in traditional methods, the present invention selects appropriate equipment according to the regional characteristics, optimizing the resource allocation;

[0037] After the offshore dredging equipment has excavated into a slope, the offshore dredging equipment and the mud suction equipment conduct layered excavation alternately. The offshore dredging equipment is responsible for the area not affected by the pile foundation; the mud suction equipment is small and flexible and can enter between the piles to suck mud, and is responsible for the area affected by the pile foundation. This collaborative operation of dividing regions and equipment makes full use of their respective advantages and significantly improves the overall mud cleaning efficiency.

[0038] Preferably, the layered retreat excavation in S42 includes the following steps: using onshore dredging equipment to excavate a first slope surface with a predetermined slope ratio.

[0039] By using onshore dredging equipment to dig a slope surface with a predetermined slope ratio, it is ensured that the excavation slope is strictly implemented in accordance with the design requirements, reducing the risk of soil landslide or collapse. Onshore dredging equipment gradually excavates during the backward excavation process, and the soil force is evenly released, avoiding local over-excavation or soil instability problems that may be caused by large-scale dredging.

[0040] Preferably, in S43, the layered excavation above water forms a second slope surface with a predetermined slope ratio, and the slope ratio of the second slope surface is the same as the slope ratio of the first slope surface.

[0041] The second slope surface with a predetermined slope ratio is formed by the water dredging equipment, and the slope ratio is kept consistent with the first slope surface formed by land excavation, so that the cross section of the area to be excavated after the second slope surface is formed is similar to an isosceles triangle (the highest point is located at the dividing line). The first slope surface and the second slope surface use the same slope ratio, which conforms to the design principle of slope stability in soil mechanics. The uniform slope ratio reduces the stress concentration of the soil on both sides of the dividing line and avoids the risk of local landslides or collapses caused by soil excavation.

[0042] Preferably, the slope ratio between the first sloping surface and the second sloping surface is 1:3, and the first sloping surface forms a plurality of platforms.

[0043] The first and second slopes both have a slope ratio of 1:3. This slope (i.e., the ratio of vertical height to horizontal distance is 1:3, about 18.4°) is widely considered to be a relatively stable gentle slope design in soil mechanics, which can effectively reduce the risk of soil landslide or collapse. Several platforms are formed on the first slope, which, on the one hand, facilitates the mooring of land dredging equipment for dredging operations, and on the other hand, further divides the slope height, slows down the continuous downward trend of the soil, and enhances the anti-slip ability of the slope.

[0044] Preferably, both the excavation on land and the excavation on water are carried out in layers, and the excavation depth of each layer is 1.5m~2m.

[0045] Both onshore and offshore excavation are carried out in layers, with the depth of each layer controlled at 1.5m~2m. This layered excavation method avoids the risk of soil instability or landslides that may be caused by one-time deep excavation. The excavation depth of 1.5m~2m per layer facilitates the control of the slope ratio, ensuring that the slope is gradually formed during the layered construction, reducing local over-excavation or under-excavation, and ensuring the overall stability of the slope.

[0046] Preferably, S5 comprises the following steps:

[0047] S51. Cut the cross seams in advance on the geotextile between the piles. At least one of the cut seams of the cross seams extends to the side of the geotextile between the piles. The diver goes into the water and sets the pile body into the pre-cut cross seams, and performs underwater sewing on the cross seams to complete the laying of the geotextile between the piles in the construction area;

[0048] S52. Drive the first open-bottom barge to dump stones in the area between adjacent pile caps. When the pile body is exposed during the low tide period, drive the second open-bottom barge to lean against the pile body and dump stones in the projection area of the pile cap. The volume of the second open-bottom barge is smaller than that of the first open-bottom barge.

[0049] Due to the reverse construction method, the casting of the pile cap has been completed when laying the geotextile, and the projection of the pile cap completely covers the pile body. Therefore, the traditional laying method of directly sleeving the geotextile from the top of the pile body downwards is no longer applicable. The method for laying the geotextile between the piles provided by the present invention pre-cuts cross seams at the position of the pile body in advance before construction, and the cross seams can extend to the side of the geotextile. When in use, it is not necessary to sleeve from the top of the pile body downwards, but to pass the pile body through the geotextile between the piles through the cross seams underwater, and then sew the cross seams, ensuring that the geotextile can still be completely covered around the steel pile when the pile cap has been constructed, effectively avoiding the problem of the lack of geotextile in the vertical projection area of the pile cap in the traditional method, and ensuring the continuity and integrity of the overall laying effect;

[0050] Similarly, due to the influence of the pile cap, it is difficult for ordinary open-bottom barges to get completely close to the pile body, resulting in the area under the pile cap being difficult to be effectively covered by stones. The method for dumping stones between the piles provided by the present invention first uses the first open-bottom barge with a larger cabin volume to perform preliminary stone dumping between two adjacent rows of pile caps. However, due to the large volume of the first open-bottom barge and the blockage of the pile cap, some areas close to the pile foundation and the pile cap are difficult to be effectively covered, that is, there are blind areas for stone dumping. To solve this problem, then, during the low tide period, the highest point of the second open-bottom barge can be lower than the bottom surface of the pile cap, so the second open-bottom barge can smoothly move under the pile cap, and the second open-bottom barge with a smaller cabin volume is used for supplementary stone dumping, solving the problem of difficult coverage and easy omission of stone dumping under the pile cap in the traditional stone dumping method.

[0051] Compared with the prior art, the beneficial effects of the present invention:

[0052] 1. The present invention provides a reverse construction method of "pile first and mud later" for high-pile wharves, which makes full use of the condition that the positions of the wharf pile foundations are basically located in the existing land area, directly driving the pile foundations in the land environment first without waiting for the completion of dredging. This reverse construction method of "pile first and mud later" greatly reduces the pre-construction preparation time and significantly shortens the overall construction period. The pile driving in the land area has low dependence on equipment, and traditional onshore pile foundation construction equipment can be used, with lower operation costs, less maintenance and rental costs, thus effectively reducing the operation costs and operation risks;

[0053] 2. The present invention provides a reverse construction method for high-piled wharves, where the pile caps are integrally connected to form pile clamping before dredging. Compared with the traditional pile clamping structure that connects the pile bodies, the pile clamping design of the present invention does not occupy the working space between piles, ensuring sufficient passage space for dredging machinery and significantly improving the efficiency and safety of subsequent dredging operations.

[0054] 3. The present invention provides a reverse construction method for high-piled wharves. Since the pile foundation is completed in the land environment, the subsequent dredging operation between piles can first be carried out using onshore dredging equipment, which has low equipment operation costs and high dredging efficiency. Then, in cooperation with offshore dredging equipment, supplementary excavation is carried out for the sea-side area, and the suction equipment shuttles between the piles to accurately remove the residual silt, further improving the dredging efficiency between piles. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 is a flow chart of the reverse construction method for high-piled wharves with pile first and mud later;

[0056] Figure 2 is a schematic diagram of the state when the pile foundation is inside the positioning frame;

[0057] Figure 3 is a schematic diagram of pile clamping;

[0058] Figure 4 is a schematic diagram of the cofferdam position;

[0059] Figure 5 is a schematic diagram of onshore excavation;

[0060] Figure 6 is a schematic diagram of offshore excavation by a grab dredger;

[0061] Figure 7 is a schematic diagram of offshore excavation by a cutter suction dredger;

[0062] Figure 8 is a schematic diagram of the suction equipment removing the residual soil on the remaining slope;

[0063] Figure 9 is a schematic diagram of the cutter suction dredger removing the residual soil on the remaining slope;

[0064] Figure 10 is a schematic diagram after the dredging operation between piles is completed;

[0065] Figure 11 is a schematic diagram of the geotextile laying between piles;

[0066] Figure 12 is a schematic diagram of the stone throwing between piles.

[0067] Markings in the figures:

[0068] 1 - Pile foundation, 2 - Pile cap, 3 - Onshore dredging equipment, 4 - Suction dredging equipment, 5 - Geotextile between piles, 6 - Positioning frame, 7 - Fixing frame, 8 - Tripod, 9 - Cofferdam, 10 - Designed slope surface, 11 - First slope surface for release, 111 - Platform, 12 - Second slope surface for release, 13 - First open hopper barge, 14 - Second open hopper barge, 15 - Grab dredger, 16 - Cutter suction dredger, 100 - Bank slope. Detailed implementation manners

[0069] The present invention will be further described in detail below in combination with specific embodiments. However, it should not be understood that the scope of the above-mentioned subject matter of the present invention is limited to the following embodiments. All technologies implemented based on the content of the present invention belong to the scope of the present invention.

[0070] In the description of the specific embodiments of the present invention, without special explanation, the expression terms indicating the orientation or positional relationship such as "upper", "lower", "left", "right", "center", "inner", "outer", etc. are all based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the invention product / equipment / device is usually used and placed. These terms of orientation or positional relationship are only for the convenience of describing the solution of the present invention or simplifying the description in the specific embodiments, so as to facilitate 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 positional relationship. Therefore, it cannot be understood as a limitation to the present invention.

[0071] In addition, for terms such as "horizontal", "vertical", "hanging", "parallel", etc., it does not mean that the corresponding device / component / element is required to be absolutely horizontal or vertical or hanging or parallel, but can be slightly inclined or have a deviation. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined. Or, it can be simply understood that the corresponding device / component / element is arranged in the directions of "horizontal", "vertical", "hanging", "parallel", etc., and can have an error / deviation of ±10% relative to the corresponding direction setting, more preferably within ±8%, more preferably within ±6%, more preferably within ±5%, more preferably within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its function in the solution of the present invention.

[0072] In addition, the expressions such as "first", "second", "third", etc. in the terms 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 a specific component.

[0073] In addition, in the description of the embodiments of the present invention, "several", "multiple", and "a number of" represent at least two. It can be any situation such as 2, 3, 4, 5, 6, 7, 8, 9, etc., and even more than 9.

[0074] In addition, in the description of the technical solutions of the present invention, unless otherwise clearly specified / defined / restricted, when terms such as "set", "installed", "connected", "connected", "provided with", "laid", and "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 common connection means in the art such as welding, riveting, bolting, and threaded connection. Such a 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 it can be the communication inside two components.

[0075] Embodiment 1

[0076] This embodiment provides a reverse construction method of pile first and mud later for high-piled wharves, which is applicable to pile foundation construction when the pile foundation position of the high-piled wharf is basically located or entirely located in the existing land area, such as Figure 1 As shown, the reverse construction method of pile first and mud later for the high-piled wharf in this embodiment includes the following steps:

[0077] S1. Site leveling;

[0078] Specifically, there is often a silt layer in the land environment, with low and uneven bearing capacity. Direct construction may cause equipment sinking or pile foundation inclination. The land silt is replaced, 0.2 - 0.8 m of silt is removed, and the land construction platform is backfilled and leveled. The construction platform is backfilled at +3 m to +4 m. By removing the silt and carrying out replacement treatment (such as filling high-bearing capacity materials such as sand and gravel), the mechanical properties of the foundation are effectively improved, providing a reliable support for the stable operation of onshore pile driving equipment; through the replacement treatment of land silt, the backfilling and leveling of the construction platform, and the widening design towards the sea side, the stability of the construction platform is significantly improved, providing a solid foundation for subsequent pile foundation 1 construction.

[0079] S2. Use onshore pile driving equipment to construct pile foundation 1 and pour onshore pile cap 2;

[0080] Since the reverse construction method of pile first and mud later for the high-piled wharf provided in this embodiment is in the land area during pile driving, the onshore pile driving method of industrial production can be used. Specifically, this embodiment takes driving steel pipe piles as an example for description. S2 includes the following steps:

[0081] S21. For onshore pile driving, a total station can be used to position pile foundation 1. The allowable deviation of the pile is 150 mm at the cut-off pile plane, and the allowable verticality deviation of the straight pile is not more than 1%.

[0082] S22. As Figure 2 shown, for onshore pile driving, a 36m positioning frame 6 can be used to assist in pile sinking, and the positioning frame 6 is measured and installed to the designed pile position.

[0083] Before hoisting the pile, holes can be pre - drilled at the steel pipe head for hoisting the pile, and the two - end hoisting method is used for unloading the vehicle. The double - point hoisting of the steel pipe pile head is adopted for hoisting the pile into position. By adjusting the relative position of the crawler crane boom and the steel pipe pile, the lifting hook slowly rises, and one end of the steel pipe pile lifting point slowly rises. During the hoisting process, the lifting hook remains basically vertical. After the steel pipe is in a vertical posture, adjust the position and height, put it into the positioning frame 6, and both the lifting hook lifting and lowering operations are carried out slowly. Rubber sheets or rubber wheels are installed in the area where friction may occur between the pile and the pile mouth of the positioning frame 6 to prevent abrasion of the coating during pile hoisting. After using the crawler crane to hoist the pile into position, pile driving starts.

[0084] S23. When carrying out onshore pile driving, the vibratory hammer can be used to slowly insert the pile first. After the pile bottom penetrates the sand layer, replace it with a D160 diesel hammer (or HHP25 hydraulic hammer) to hammer the pile foundation 1 until the designed position. After the pile sinking is completed, cut or connect the pile head according to the designed elevation.

[0085] When using a D160 diesel hammer (or HHP25 hydraulic hammer), the pile - sinking control standard: mainly control by the penetration degree, and use the pile tip elevation as a check. Specifically, the final hammering standard is:

[0086] a1. The pile tip reaches the designed elevation. For the last three blows, ten blows in each blow (for the D160 diesel hammer in the second gear or the HHP25 hydraulic hammer, the hammer core stroke is not less than 1.2m), and the average penetration degree < 4mm / blow, then the final hammering;

[0087] b1. The pile tip reaches the designed elevation, but the penetration degree does not meet the design requirements. Continue to sink the pile until its penetration degree reaches the controlled penetration degree, or after driving the additional pile length, then the final hammering;

[0088] c1. Reach the controlled penetration degree, but the pile tip does not reach the designed elevation:

[0089] When the distance between the pile tip and the designed elevation < 1.0m, for the last three blows, ten blows in each blow (for the D160 diesel hammer in the third gear or above or the maximum stroke of the HHP25 hydraulic hammer hammer core), and the average penetration degree < 4mm / blow, then the final hammering;

[0090] When the distance between the pile tip and the designed elevation ≤ 1.5m, for the last three blows, ten blows in each blow (for the D160 diesel hammer in the third gear or above or the maximum stroke of the HHP25 hydraulic hammer hammer core), and the average penetration degree ≤ 3mm / blow, then the final hammering.

[0091] This kind of final hammering control standard, mainly controlling by the penetration degree and using the pile tip elevation as a check, avoids the limitations of relying solely on a single index of elevation or penetration degree, ensures that the pile foundation can meet the design bearing capacity requirements under different geological conditions, and improves the safety and reliability of the project.

[0092] S24. Utilize an onshore piling construction platform. After excavating to the bottom elevation of the pile cap 2, pour a concrete cushion layer, install steel bars and side forms, and then carry out the pouring of the pile cap 2.

[0093] The installation of the positioning frame 6 further enhances the positioning accuracy of the pile foundation 1. As a commonly used lifting equipment on land, the crawler crane is stable and flexible in operation, and can quickly lift the pile to the designed position, avoiding the uncertainty caused by the shaking of the floating crane ship due to wind and waves in the traditional construction method of the pile foundation 1;

[0094] When carrying out onshore piling, equipment commonly used in onshore construction such as crawler cranes, vibratory hammers, and diesel hammers are all used. Compared with the floating crane ship, pile driving boat, or special pile sinking platform 111 relied on in the traditional method, the procurement, rental, and maintenance costs are lower, and there is no need for additional ship support and water transportation costs; The vibratory hammer is suitable for the initial pile insertion, reducing the disturbance to the foundation and quickly penetrating the surface layer; The diesel hammer provides a powerful impact force after the pile bottom enters the sand layer to ensure that the pile foundation 1 reaches the designed depth. This combination method is more efficient than traditional single hammering. Especially under onshore conditions, there is no need for underwater adjustment equipment, the construction continuity is stronger. Compared with traditional underwater pile sinking, onshore piling does not require ship cooperation, reducing the time for equipment switching and positioning adjustment, and significantly improving the piling efficiency;

[0095] After the pile sinking is completed, cut or connect the pile heads according to the designed elevation. Immediately after completion, carry out the pouring of the onshore pile cap 2. Compared with traditional underwater pouring, the operation is simple, the quality is easier to control, ensuring the stability of the construction of the pile cap 2 and further improving the operation efficiency.

[0096] S3. Carry out overall connection of the pile caps 2 to form pile clamping;

[0097] Specifically, as Figure 3 shown, after the pouring of the pile cap 2 is completed, set up a fixing frame 7 on the top of adjacent pile caps 2. The fixing frame 7 can be welded on-site using channel steel. The fixing frame 7 can be in the structural form of two parallel channel steels + cross beams between the channel steels. Use a tripod 8 to fixedly connect the pile cap 2 and the fixing frame 7 from the side of the pile cap 2 to form pile clamping. The top of the tripod 8 is welded to the fixing frame 7, and the tripod 8 can be fixedly connected to the side wall of the pile cap 2 through M30 high-strength bolts. It can be understood that after the pile clamping is completed, the pile area should meet the requirements for the subsequent operation of the onshore dredging equipment 3, suction equipment 4, and the second open barge 14 to travel between the pile rows.

[0098] This pile clamping structure connects individual pile caps 2 into a whole (for example, connecting a row of pile caps 2), effectively dispersing external loads (such as the lateral force change of the pile body during the mud cleaning operation or the impact of the sea-side water flow), and preventing the pile foundation 1 from tilting or shifting due to uneven stress;

[0099] The fixing frame 7 is erected on the top of the pile cap 2, and the tripod 8 is fixed from the side, avoiding the problem that the traditional pile clamping structure (such as directly connecting the pile body or supporting at the bottom) occupies the area between the piles. This design ensures the smoothness of the space between the piles and provides sufficient passage and working space for the operation of the onshore dredging equipment 3, the offshore dredging equipment and the mud suction equipment 4 during the subsequent mud cleaning operation between the piles.

[0100] S4. Use the onshore dredging equipment 3, in cooperation with the offshore dredging equipment and the mud suction equipment 4, to carry out the mud cleaning operation between the piles;

[0101] Specifically, S4 includes the following steps:

[0102] S41. After the construction of the pile cap 2, the working area of the onshore dredging equipment 3 between the piles can be processed, backfilled and leveled to +1.9 m, facilitating the operation of the excavator and the dump truck through the passage between the bent frames; as Figure 4 shown, a cofferdam 9 of 1 m can be built on the sea side of the wharf.

[0103] Build the cofferdam 9 on the sea side of the wharf, effectively isolating the land area from the water area, creating a dry and stable working environment for onshore excavation. This isolation measure avoids the interference of tides, water currents or waves on the mud cleaning operation, ensuring the efficient operation of the onshore dredging equipment 3 under anhydrous conditions. Compared with the dredging operation completely exposed to the water area environment in the traditional method, the cofferdam 9 significantly improves the controllability and stability of the construction, laying the foundation for the subsequent steps.

[0104] S42. As Figure 5 shown, Figure 5 the shaded inverted triangular area in the figure is the area to be excavated onshore. Use the onshore dredging equipment 3 to carry out onshore excavation of the pile foundation area. During onshore excavation, gradually carry out layered backhoe excavation from the cofferdam 9 towards the land area and slope according to the construction requirements. The excavation depth gradually increases until the designed slope surface 10 of the bank slope 100 is excavated; it can be understood that the onshore dredging equipment 3 here can be an excavator, specifically, for example, an excavator with a specification of 40 t, and / or, an excavator with a 22 m long arm.

[0105] Furthermore, the layered backhoe excavation may include the following steps: Use the onshore dredging equipment 3 to excavate to form a first slope surface 11 with a predetermined slope ratio. By using the onshore dredging equipment 3 to excavate to form a slope surface with a predetermined slope ratio, it is ensured that the excavation slope strictly complies with the design requirements, reducing the risk of soil landslide or collapse. During the backhoe excavation process, the onshore dredging equipment 3 gradually excavates, and the soil stress is evenly released, avoiding the problems of local over-excavation or soil instability that may be caused by large-scale dredging.

[0106] In the further embodiments of this embodiment or other embodiments, the slope ratio of the first slope surface 11 can be 1:3, and a plurality of platforms 111 can be formed on the first slope surface 11 during the backhoe excavation process. Forming a plurality of platforms 111 on the first slope surface 11 facilitates the berthing of the onshore dredging equipment 3 for dredging operations on the one hand, and further divides the slope height on the other hand, slowing down the continuous sliding trend of the soil mass and enhancing the anti-sliding ability of the slope surface.

[0107] Areas that are difficult to excavate between the piles can be assisted by flushing with a high-pressure water gun.

[0108] Furthermore, in this embodiment or other embodiments, the onshore excavation can be carried out in layers at a rate of 1.5m to 2m per layer, and the slope ratio of the designed slope surface 10 of the bank slope 100 in this embodiment or other embodiments can be 1:2.

[0109] The onshore dredging equipment 3 performs layered backhoe excavation step by step from the cofferdam 9 towards the land area. Compared with traditional bulky offshore dredging equipment, it is smaller in volume and more maneuverable, and can directly drive into the space between the pile foundations 1 for mud cleaning operations, solving the defect that traditional offshore equipment cannot enter the space between piles for excavation due to its excessive volume; the layered backhoe excavation makes full use of the high efficiency and flexibility of onshore equipment, and the excavation depth gradually increases to form a certain slope surface, which not only improves the mud cleaning efficiency but also ensures the stability of the excavation area, avoiding the risk of slope collapse caused by underwater soil disturbance in traditional methods.

[0110] S43. As Figure 6 shown, Figure 6 the shaded triangular area in the figure, including the cofferdam 9, is the area to be excavated offshore.

[0111] Taking the edge of the pile cap 2 closest to the sea side as the demarcation line, use offshore dredging equipment to perform layered offshore excavation step by step from the demarcation line towards the sea side, and the excavation depth gradually increases.

[0112] Furthermore, the layered offshore excavation can form a second slope surface 12 with a predetermined slope ratio, and the slope ratio of the second slope surface 12 is the same as that of the first slope surface 11.

[0113] By forming a second slope surface 12 with a predetermined slope ratio through offshore dredging equipment and keeping the slope ratio consistent with that of the first slope surface 11 formed by onshore excavation, the subsequent area to be excavated after the second slope surface 12 is sloped has a cross-section similar to an isosceles triangle (for example Figure 8 shown, the highest point of the triangle is located at the demarcation line). The first slope surface 11 and the second slope surface 12 have the same slope ratio, which conforms to the design principle of slope stability in soil mechanics. The unification of the slope ratio reduces the stress concentration on both sides of the demarcation line of the soil mass, avoiding the risk of local landslides or collapses caused by soil excavation.

[0114] Both the first slope surface 11 and the second slope surface 12 adopt a slope ratio of 1:3. This slope (i.e., the ratio of the vertical height to the horizontal distance is 1:3, approximately 18.4°) is widely considered in soil mechanics to be a relatively stable gentle slope design, which can effectively reduce the risk of soil landslides or collapses.

[0115] Taking the pile cap 2 closest to the sea side as the demarcation line, the area on the sea side that is not blocked by the pile foundation 1 can be excavated in layers using large-scale water dredging equipment. This targeted design gives full play to the high-efficiency operation ability of water equipment in a large-scale and unobstructed area. The excavation depth gradually increases to form a stable slope surface, further improving the construction efficiency and ensuring the terrain quality. Compared with the low efficiency of the traditional method that relies entirely on water equipment throughout the process, the present invention selects appropriate equipment according to the regional characteristics and optimizes the resource allocation.

[0116] Furthermore, in this embodiment or other embodiments, the water dredging equipment can be a grab dredger 15 and a cutter suction dredger 16. Specifically, the grab dredger 15 can be a grab ship with a specification of 8m 3 . As Figure 6 shown, the grab dredger 15 can be used to grab and clean the silt layer. As Figure 7 shown, the cutter suction dredger 16 can be used to clean the sandy soil layer. In this embodiment or other embodiments, during water excavation, it can be excavated in layers at a rate of 1.5m to 2m per layer. The grab dredger 15 and the cutter suction dredger 16 can alternate construction and excavate in layers when encountering different soil types. Specifically, for example, when encountering silty clay layers or clay layers, the grab dredger 15 can be used for excavation, and when encountering sandstone or siltstone, the cutter suction dredger 16 can be used for excavation.

[0117] In this embodiment or other embodiments, both land excavation and water excavation are carried out in layers, and the depth of each layer is controlled within 1.5m to 2m. This layering method avoids the risk of soil instability or landslides that may be caused by one-time large-depth excavation; the excavation depth of 1.5m to 2m per layer is convenient for controlling the slope ratio of the slope surface, ensuring that the slope surface is gradually formed during layered construction, reducing local over-excavation or under-excavation phenomena, and ensuring the overall stability of the slope surface.

[0118] S44. After the water dredging equipment excavates into a slope (i.e., after the second slope surface 12 forms a slope), the remaining slope residual soil is removed by alternately using the water dredging equipment and the mud suction equipment 4. As Figure 9 shown, the water dredging equipment can excavate the side facing the water area along the demarcation line of the layered excavation; as Figure 8 shown, the mud suction equipment 4 enters between the piles to excavate the side facing the land area along the demarcation line in layers. It can be understood that the mud suction equipment 4 can specifically be a small suction ship with a high-pressure water gun and a silt pumping function. The specific specification of the small suction ship can be 500m 3 / day. AsFigure 10 as shown until the soil cleaning work between the wharf piles is completed.

[0119] After the underwater dredging equipment excavates to form a slope, the underwater dredging equipment and the mud suction equipment 4 alternate in excavation. The underwater dredging equipment is responsible for the area not affected by the pile foundation 1, and the mud suction equipment 4 is small and flexible, capable of entering between the piles to suck mud and is responsible for the area affected by the pile foundation 1. This collaborative operation of dividing the area and equipment makes full use of their respective advantages and significantly improves the overall mud cleaning efficiency.

[0120] S5. After laying the geotextile 5 between the piles, carry out the stone throwing operation between the piles.

[0121] Furthermore, S5 includes the following steps:

[0122] S51. Due to the reverse construction method, the casting of the pile cap 2 has been completed when laying the geotextile, and the projection of the pile cap 2 completely covers the pile body. Therefore, the traditional laying method of directly sleeving the geotextile from the top of the pile body downwards is no longer applicable. Thus, as Figure 11 shown, according to the instructions of the construction drawings in advance, and based on the positions of the pile foundation 1 and the corresponding pile cap 2, cut a cross seam on the geotextile 5 between the piles. The two cut seams of the cross seam can be perpendicular to each other, and at least one cut seam of the cross seam extends to the side of the geotextile 5 between the piles. For example, the longer cut seam of the cross seam can start from one long side of the geotextile 5 between the piles and extend towards the midline direction of the geotextile 5 between the piles, and the other shorter cut seam of the cross seam is perpendicular to the longer cut seam. This cutting method is convenient for the pile foundation 1 to enter the geotextile 5 between the piles from the longer cut seam later. It can be foreseen that the length of the cut seam of the cut cross seam is not less than the diameter of the pile body, and the shorter cut seam and the longer cut seam may not be perpendicular to each other. During laying, the diver goes underwater to sleeve the pile body into the pre-cut cross seam and perform underwater seam connection of the cross seam to complete the laying of the geotextile 5 between the piles in the construction area.

[0123] This method of laying the geotextile 5 between the piles pre-cuts a cross seam at the position of the pile body before construction, and the cross seam can extend to the side of the geotextile. When in use, it is not necessary to sleeve it from the top of the pile body downwards, but to pass the pile body through the geotextile 5 between the piles through the cross seam underwater and then sew the cross seam, ensuring that the geotextile can still be completely covered around the steel pile when the pile cap 2 has been constructed, effectively avoiding the problem of the lack of geotextile in the vertical projection area of the pile cap 2 in the traditional method and ensuring the continuity and integrity of the overall laying effect.

[0124] S52. Similarly, during the rock dumping operation, due to the influence of the pile cap 2, an ordinary open barge cannot fully approach the pile body, resulting in the area under the pile cap 2 being difficult to be effectively covered by stones. Therefore, the first open barge 13 can be driven to dump stones in the area between adjacent pile caps 2 first. When the pile body is exposed during the low tide period, for example, the highest point of the second open barge 14 can be lower than the bottom surface of the pile cap 2. In this way, the second open barge 14 can be driven to fully lean against the pile body to dump stones in the projection area of the pile cap 2. The volume of the second open barge 14 is smaller than that of the first open barge 13. This method of dumping stones between piles first uses the first open barge 13 with a larger hold capacity to conduct preliminary stone dumping between two adjacent rows of pile caps 2. However, due to the large volume of the first open barge 13 and the obstruction of the pile cap 2, some areas close to the pile foundation 1 and the pile cap 2 are difficult to be effectively covered, that is, there are stone dumping blind areas. To solve this problem, then, during the low tide period, since the highest point of the second open barge 14 can be lower than the bottom surface of the pile cap 2, the second open barge 14 can smoothly move under the pile cap 2, and the second open barge 14 with a smaller hold capacity is used for supplementary stone dumping, solving the problems of difficult coverage and easy omission of stone dumping under the pile cap 2 in the traditional stone dumping method.

[0125] The traditional construction method of the pile foundation 1 of a high-pile wharf needs to complete a large-scale dredging operation before pile driving. The construction process is limited by the dredging progress, often resulting in project delays. The underwater pile driving operation is interfered by adverse factors such as tides and winds, with great positioning difficulty and low accuracy, and strong dependence on floating cranes, pile driving boats or special pile driving platforms, resulting in extremely high construction costs and relatively high risks in the underwater pile driving operation.

[0126] However, the reverse construction method of "driving piles first and then dredging" (driving piles and constructing pile caps first, and then dredging the mud between piles) provided in this embodiment makes full use of the condition that the positions of the wharf pile foundations are basically located in the existing land area, directly driving the pile foundation 1 in the land environment first without waiting for the dredging to be completed. This reverse construction method of "driving piles first and then dredging" greatly reduces the preliminary preparation time and significantly shortens the overall construction period. The land pile driving has low dependence on equipment, and traditional onshore pile foundation construction equipment can be used, with lower operating costs, less maintenance and rental costs, thus effectively reducing the operation costs and operation risks.

[0127] To avoid the change of the pile body force caused by the subsequent mud cleaning operation between piles and prevent the pile body from tilting or shifting due to uneven force, in this embodiment, the pile caps 2 are integrally connected to form pile clamping before mud cleaning. Compared with the traditional pile clamping structure for connecting the pile body, the pile clamping design in this embodiment does not occupy the operation space between piles, ensuring sufficient passage space for the mud cleaning machinery and significantly improving the efficiency and safety of the subsequent mud cleaning operation.

[0128] Since the pile foundation 1 is completed in the land environment, for the subsequent mud cleaning operation between piles, the land dredging equipment 3 can be first used for cleaning, with low equipment operation cost and high dredging efficiency. Then, the water dredging equipment is used to supplement the excavation in the sea side area, and the suction dredging equipment 4 shuttles between the piles to accurately remove the residual silt, further improving the mud cleaning efficiency between piles.

[0129] Finally, after laying the geotextile 5 between the piles, the rock filling operation is carried out to stabilize the area between the piles and ensure the long-term stability of the wharf foundation. By changing the construction sequence (driving piles first and then cleaning mud) and making full use of land equipment and conditions, this embodiment overcomes the deficiencies of the traditional method, such as long construction period, high cost and high risk of underwater pile driving operation, and provides an efficient and economical solution for similar projects.

[0130] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A construction method of reverse sequence of pile first and mud later for high-piled wharf, characterized in that It includes the following steps: S1. Site leveling; S2. Use onshore piling equipment to construct the pile foundation (1) and pour the onshore pile cap (2); S3. Integrally connect the pile caps (2) to form pile clamping; S3 includes the following steps: After the pile cap (2) is poured, set up a fixing frame (7) on the top of adjacent pile caps (2), and use a tripod (8) to fixedly connect the pile cap (2) and the fixing frame (7) from the side of the pile cap (2) to form pile clamping; S4. Use onshore dredging equipment (3), in cooperation with offshore dredging equipment and mud suction equipment (4), to carry out mud cleaning operation between piles; S4 includes the following steps: S41. Build a cofferdam (9) on the sea side of the wharf; S42. Use onshore dredging equipment (3) to carry out onshore excavation in the pile foundation area. During onshore excavation, gradually carry out layered backhoe excavation and slope setting from the cofferdam (9) towards the land area, and the excavation depth gradually increases until the designed slope surface (10); S43. Taking the pile cap (2) closest to the sea side as the demarcation line, use offshore dredging equipment to gradually carry out layered offshore excavation from the demarcation line towards the sea side, and the excavation depth gradually increases; S44. After the offshore dredging equipment excavates into a slope, alternately use the offshore dredging equipment and the mud suction equipment (4) to remove the remaining slope residual soil. The offshore dredging equipment excavates the side of the demarcation line facing the water area in layers, and the mud suction equipment (4) enters between the piles to excavate the side of the demarcation line facing the land area in layers until the soil cleaning work between the wharf piles is completed; S5. After laying the geotextile (5) between piles, carry out stone throwing operation between piles; S5 includes the following steps: S51. Cut a cross seam in advance on the geotextile (5) between piles. At least one cut seam of the cross seam extends to the side of the geotextile (5) between piles. Divers go into the water to put the pile body into the pre-cut cross seam and carry out underwater seam connection of the cross seam to complete the laying of the geotextile (5) between piles in the construction area; S52. Drive the first open barge (13) to throw stones in the area between adjacent pile caps (2). When the pile body is exposed during the low tide period, drive the second open barge (14) to lean against the pile body and throw stones in the projected area of the pile cap (2). The volume of the second open barge (14) is smaller than that of the first open barge (13).

2. The reverse construction method of pile first and mud later for high-piled wharf according to claim 1, characterized in that S1 includes the following steps: Carry out replacement treatment of the land area silt, remove 0.2 - 0.8 m of silt, backfill and level the land construction platform, and backfill the construction platform at +3 m to +4 m.

3. A reverse construction method of high-piled wharf with pile driving first and mud filling later according to claim 1, characterized in that, S2 includes the following steps: S21. Position the pile foundation (1); S22. Measure and install the positioning frame (6) to the designed pile position, and start driving the pile after using the crawler crane to lift the pile into position; S23. Carry out onshore piling: First, use a vibratory hammer to insert the pile. When the pile bottom penetrates the sand layer, replace it with a diesel hammer to hammer the pile foundation (1) until the designed position; S24. Using the onshore piling construction platform, excavate to the bottom elevation of the pile cap (2), pour the concrete cushion, install the steel bars and side forms, and carry out the pouring of the pile cap (2).

4. A reverse construction method for high-piled wharves with pile driving first and mud filling later according to claim 1, characterized in that The layered backhoe excavation in S42 includes the following steps: Use onshore dredging equipment (3) to excavate to form a first slope surface (11) with a predetermined slope ratio.

5. A construction method for a high-piled wharf with pile driving first and mud dredging later in reverse order according to claim 4, characterized in that In S43, a second slope surface (12) with a predetermined slope ratio is formed by stratified underwater excavation, and the slope ratio of the second slope surface (12) is the same as that of the first slope surface (11).

6. A construction method of constructing piles first and then mud in reverse sequence for high-piled wharves according to claim 5, characterized in that, The slope ratios of the first slope surface (11) and the second slope surface (12) are 1:3, and the first slope surface (11) forms several platforms (111).

7. A reverse construction method for high-piled wharves with pile driving first and mud filling later according to claim 1, characterized in that, Both the onshore excavation and the underwater excavation are stratified excavations, and the excavation depth of each layer is 1.5 m to 2 m.

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