A hybrid structure old dock reconstruction and expansion construction method and structure

Abstract

The present invention provides a construction method and structure for reconstruction and expansion of an old wharf with a mixed structure, wherein the construction method includes breaking and leveling the upper rear end of the concrete block of the old wharf to form a first groove; removing the surface layer, the first filling layer and the vertical beam on the top of the middle panel of the old wharf to expose the middle panel of the old wharf flatly; opening a plurality of through holes for cast-in-place pile construction on the middle panel of the old wharf, and constructing cast-in-place piles at positions corresponding to each through hole; removing the middle panel of the old wharf and breaking the old wharf foundation piles under the middle panel of the old wharf; building a new wharf on the top of the cast-in-place piles, and setting a buffer plate between the front end of the new wharf and the first groove, and there is a gap between the bottom of the new wharf and the first groove; respectively building retaining walls on the left, right and rear sides of the new wharf, and setting a buffer plate between the retaining wall and the new wharf. The present invention aims to solve the shortcomings of the existing construction method for reconstruction and expansion of an old wharf with a mixed structure.

Description

Technical Field

[0001] The invention belongs to the technical field of dock construction, and in particular relates to a construction method and structure for reconstruction and expansion of an old dock with a mixed structure. Background Art

[0002] Some old docks that have been in operation for decades are mixed-structure docks with high-pile beam-slab docks and gravity docks. Because the specifications adopted in their design and construction are versions from decades ago, the thickness of the protective layer of the dock surface layer, the bottom of the longitudinal and transverse beams and other locations of their high-pile beam-slab dock structures is relatively thin. Under the collision of various operating machinery, the protective layer has often fallen off, the steel bars have leaked out, and the dock panels are damaged and can no longer meet the needs of modern vehicle operation. The effective pre-stress value of the driven piles decades ago is relatively small, and the probability of cracks in the pile body during the pile sinking construction stage is high. The piles are large and the technology is backward. The pile length and diameter are small. The bearing capacity cannot meet the transshipment load of modern ships and cargoes. In addition, during decades of operation, the berthing force of ships, the mooring force, the adsorption force of oysters and the wave force of the ebb and flow of tides often cause the concrete at the pile heads to crack and fall off. The chloride ions in seawater cause the diameter of the steel bars to become smaller and the physical and mechanical properties to be greatly reduced. The pile foundation can no longer withstand the constant loads of bridge cranes and containers during the operation stage. Therefore, after a period of operation, the high-pile beam-slab wharf often needs to be renovated and expanded.

[0003] The gravity dock structure uses plain concrete structure, which is more than ten meters deep. Due to its own material properties, concrete is often not weakened by decades of corrosion by seawater. Therefore, in the reconstruction of the old dock, if tens to hundreds of tons of concrete blocks are removed, the manpower, machinery costs and time cycle consumed are very huge. In addition, the concrete falls into the sea during the construction process, causing the sea depth to become shallower, and the construction ship will be unable to carry out the removal operation because it hits the bottom. Therefore, the technical difficulty and cost of the traditional mixed structure old dock construction often lead to the stranding of dock reconstruction.

[0004] The reconstruction of the traditional mixed structure wharf of high pile beam slab wharf and gravity wharf often uses a large amount of stones for filling in the soft soil foundation. The surface layer is a reinforced concrete structure. The volume of stones required for filling often reaches tens of thousands to hundreds of thousands of cubic meters, which is very costly. In addition, due to the existence of soft soil foundation below, the bearing capacity of the foundation is weak. Even if a block stone layer with a higher bearing capacity is used above, after the reconstruction of the new wharf pavement is completed, there will be a large settlement after a few years, making the wharf unable to operate. Summary of the invention

[0005] The purpose of the present invention is to provide a hybrid structure old wharf reconstruction and expansion construction method and structure, aiming to solve the shortcomings of the existing hybrid structure old wharf reconstruction and expansion construction method.

[0006] The present invention is achieved through the following technical solutions:

[0007] A construction method for reconstruction and expansion of an old dock with a mixed structure, comprising the following steps:

[0008] The upper rear end of the concrete block of the old dock is broken and leveled to form the first groove;

[0009] Remove the surface layer, the first filling layer and the vertical beam on the top of the middle panel of the old wharf to expose the middle panel of the old wharf flatly;

[0010] A plurality of through holes for cast-in-place pile construction are opened on the middle panel of the old wharf, and cast-in-place piles are constructed at positions corresponding to each through hole;

[0011] Removing the middle panel of the old pier and breaking the old pier foundation piles below the middle panel of the old pier;

[0012] A new wharf is constructed on the top of the cast-in-place pile, a buffer plate is arranged between the front end of the new wharf and the first groove, and a gap exists between the bottom of the buffer plate and the first groove;

[0013] Retaining walls are built on the left, right and rear sides of the new wharf, and buffer plates are set between the retaining walls and the new wharf.

[0014] Furthermore, the plurality of cast-in-place piles are divided into four rows, and the four rows of cast-in-place piles are arranged at equal intervals along the land toward the sea, a new wharf is built on the top of the cast-in-place piles, a buffer plate is arranged between the front end of the new wharf and the first groove, and a buffer plate is arranged between the bottom of the buffer plate and the first groove. The construction steps include:

[0015] Laying a sand cushion layer at the bottom of the first groove;

[0016] Except for a row of cast-in-place piles on the side closest to the land, a support system is installed on the upper part of the remaining cast-in-place piles, wherein the support system includes a corbel welded to the cast-in-place pile, a load-relief block and a support beam are arranged on the corbel in sequence, a main beam is erected on the support beam, a transfer beam and a wooden beam are arranged on the main beam at intervals, a wooden template is laid above the transfer beam and the wooden beam, and the bottom surface of one end of the wooden template abuts against the surface of the sand cushion layer;

[0017] Stones are dumped on the revetment structure to form a block stone bottom formwork, and a first concrete cushion layer is laid on the block stone bottom formwork at the rear side of the wooden formwork. The first concrete cushion layer is at the same elevation as the top of the wooden formwork, and the two are connected to form a bottom formwork;

[0018] A buffer plate is installed on the side wall of the first groove, and concrete is poured on the bottom formwork. After the concrete reaches the designed curing period, the support system and sand cushion layer are removed to form a new wharf.

[0019] Furthermore, the construction steps for dismantling the support system include:

[0020] Before pouring concrete on the bottom formwork, for each bored pile within the range of the wooden formwork, multiple embedded pipes are set around the bored pile. The top elevation of the embedded pipe is consistent with the top elevation of the newly built wharf, and its bottom passes through the wooden formwork;

[0021] After the concrete poured on the bottom formwork reaches the designed curing period, for each embedded pipe, a steel wire rope is passed through the embedded pipe and pulls the corresponding support beam;

[0022] Remove the unloading blocks and corbels, lower the supporting beams, main beams, transfer beams and wooden planks onto the floating raft via steel wire ropes, and remove the wooden formwork.

[0023] Furthermore, the pile diameter of the row of cast-in-place piles closest to the sea area among the four rows of cast-in-place piles is greater than the pile diameters of the other cast-in-place piles, and / or the pile tips of the row of cast-in-place piles closest to the sea area among the four rows of cast-in-place piles enter the hard soil layer at least 8 times their pile diameter, and the pile tips of the other cast-in-place piles enter the hard soil layer at least 5 times their pile diameter.

[0024] Furthermore, the construction steps of building a retaining wall at the rear side of the newly built wharf and setting a buffer plate between the retaining wall and the newly built wharf include:

[0025] Dig construction trenches at the locations where the revetment structure is located on the left, right and rear sides of the new pier;

[0026] Fill the construction trench with a crushed stone cushion layer and pour the second concrete cushion layer in sequence;

[0027] Install buffer plates at the left, right and rear ends of the new dock;

[0028] constructing the retaining wall on the second concrete pad;

[0029] The backfill sand layer and the road surface layer are constructed sequentially in the construction trench.

[0030] Further, the construction steps of the cast-in-place pile include:

[0031] Bury casing → drill holes → install steel cage → clean holes → pour concrete.

[0032] Furthermore, after the steps of breaking and leveling the upper rear end of the concrete block of the old wharf, the method further comprises:

[0033] Removal of fender pilings and old fenders on the old dock;

[0034] Several rubber fenders are installed at the front end of the concrete block of the old dock, and several mooring posts are installed at the upper end.

[0035] The present invention also provides a mixed-structure old dock reconstruction and expansion structure, including concrete blocks of the old dock, a new dock arranged at the rear side of the concrete blocks, and a revetment structure arranged below the new dock, a plurality of cast-in-place piles are arranged at the bottom of the new dock, a first groove is arranged at the upper rear side of the concrete blocks, a buffer plate is arranged between the front end of the new dock and the first groove, a spacer is arranged between the bottom of the new dock and the first groove, retaining walls are respectively arranged on the left side, right side and rear side of the new dock, the retaining wall is arranged in the revetment structure, and a buffer plate is arranged between the retaining wall and the new dock.

[0036] Furthermore, the newly built wharf includes a plurality of pedestal sections connected in sequence, a protrusion is provided at one end of the pedestal section, and a second groove is provided at the other end, the protrusion and the second groove match each other, a buffer plate is provided between two adjacent pedestal sections, and / or the retaining wall includes a plurality of structural sections, and a buffer plate is provided between two adjacent structural sections.

[0037] Furthermore, a drainage ditch is provided on the surface of the newly built dock near its front end, the bottom of the drainage ditch is connected to the bottom of the newly built dock through a number of drainage pipes, a fence cover is provided at the top opening of the drainage ditch, and / or a floor drain is provided on the surface of the newly built dock near its rear end, and the floor drain is connected to the bottom of the newly built dock through a drainage pipe.

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows: the concrete blocks of the existing old wharf are used as the main body to bear the upper operating load, and only the wharf part behind the concrete blocks is demolished, which can save a lot of time and cost; the new wharf adopts a cantilever structure, and there is a gap between it and the concrete blocks. The operating load above the new wharf will not be transmitted to the concrete blocks of the old wharf, which can effectively ensure the stability of the concrete blocks of the old wharf; the foundation piles adopt cast-in-place piles, which can ensure the stability of the new wharf and reduce the settlement of the wharf under various mechanical loads during the operation stage; the new wharf is connected to the concrete blocks and retaining walls through buffer plates. When the concrete blocks of the old wharf are squeezed by the docked ships, the buffer plates can be used to Part of the force is transmitted to the newly built wharf at the rear, and the newly built wharf transmits part of the force to the retaining wall at the rear. On the one hand, the coordination and consistency between the concrete blocks of the old wharf and the newly built wharf are ensured, and the displacement between the two is reduced or even avoided to buffer the displacement between different structures. On the other hand, the bearing capacity of the newly built wharf is fully utilized to effectively alleviate the force on the concrete blocks of the old wharf, thereby increasing the overall bearing capacity of the wharf and further avoiding the force damage between the newly built wharf and the concrete blocks. The present invention improves the construction efficiency of the reconstruction and expansion of the old wharf, shortens the construction period, ensures the quality of the newly built wharf after reconstruction and expansion, reduces the settlement of the wharf during the operation stage, ensures the quality of the wharf operation, and shortens the time of interruption of the wharf operation due to reconstruction. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1It is a flow chart of the steps of the construction method for reconstruction and expansion of an old dock with a mixed structure according to the present invention;

[0040] Figure 2 It is a schematic diagram of the reconstruction and expansion structure of the old dock with a hybrid structure according to the present invention;

[0041] Figure 3 for Figure 2 A magnified schematic diagram of part A;

[0042] Figure 4 It is a top view of a part of the structure of the hybrid structure old wharf reconstruction and expansion structure of the present invention;

[0043] Figure 5 This is a schematic diagram of the old dock;

[0044] Figure 6 It is a schematic diagram of the support system of a new dock in the hybrid structure of the old dock reconstruction and expansion structure of the present invention;

[0045] Figure 7 This is a pile position arrangement diagram of the foundation section in the hybrid structure old wharf reconstruction and expansion structure of the present invention.

[0046] In the figure, 11-concrete blocks, 12-driven concrete piles, 13-panel, 14-vertical beams, 15-first filling layer, 16-surface layer, 17-fender baffle piles, 18-old fender, 2-new dock, 21-cap section, 211-protrusion, 212-second groove, 22-drainage trough, 23-drainage pipe, 3-bank protection structure, 31-gravel cushion layer, 32-second concrete cushion layer, 33 - backfill sand layer, 34- road surface layer, 4- cast-in-place piles, 5- buffer plate, 6- retaining wall, 61- structure segment, 71- rubber fender, 72- bollard, 8- sand cushion layer, 9- support system, 91- corbel, 92- unloading block, 93- support beam, 94- main beam, 95- transfer beam, 96- wooden beam, 97- wooden formwork, 98- block stone bottom formwork, 99- first concrete cushion layer, 910- embedded pipe. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0048] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. At the same time, in the description of the present invention, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0050] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0051] In the description of the present invention, it should be noted that the terms "upper", "lower", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are directions or positional relationships in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0052] See also Figures 1 to 5 , Figure 1 This is a flow chart of the steps of the hybrid structure old wharf reconstruction and expansion construction method of the present invention. Figure 2 This is a schematic diagram of the hybrid structure of the old dock reconstruction and expansion structure of the present invention. Figure 3 for Figure 2 A magnified schematic diagram of part A, Figure 4 This is a partial structural top view of the hybrid structure of the old wharf reconstruction and expansion structure of the present invention. Figure 5 A construction method for reconstruction and expansion of an old wharf with a mixed structure includes the following steps:

[0053] S1, breaking and leveling the upper rear end of the concrete block 11 of the old wharf to form a first groove;

[0054] S2, removing the surface layer 16, the first filling layer 15 and the vertical beam 14 on the top of the middle panel 13 of the old wharf, so that the middle panel 13 of the old wharf is exposed flat;

[0055] S3, opening a plurality of through holes for the construction of cast-in-place piles 4 on the middle panel 13 of the old wharf, and constructing cast-in-place piles 4 at the position corresponding to each through hole;

[0056] S4, dismantling the middle panel 13 of the old wharf and breaking the old wharf foundation piles below the middle panel 13 of the old wharf;

[0057] S5, construct a new dock 2 on the top of the cast-in-place pile 4, and set a buffer plate 5 between the front end of the new dock 2 and the first groove, with a gap between the bottom of the buffer plate and the first groove;

[0058] S6. Build retaining walls 6 on the left side, right side and rear side of the newly built wharf 2 respectively, and set a buffer plate 5 between the retaining wall 6 and the newly built wharf 2.

[0059] The present invention is used for the reconstruction and expansion of an old dock, which is a mixed structure old dock. The mixed structure old dock includes a concrete block 11 on the side close to the sea, a high pile beam slab structure on the side close to the land, foundation piles arranged at the bottom of the high pile beam slab structure, and a revetment structure 3 located below the high pile beam slab structure. Below the concrete block 11 is a riprap prism, the foundation piles are driven concrete piles 12, the high pile beam slab structure includes a panel 13, a plurality of vertical beams 14 above the panel 13, a first filling layer 15 between two adjacent vertical beams 14, and a surface layer 16 arranged on the vertical beams 14 and the first filling layer 15. A fender baffle pile 17 is arranged on the side of the concrete block 11 facing the sea, and an old fender 18 is arranged on the upper part of the fender baffle pile 17.

[0060] In the above step S1, the surface of the old dock is cleaned to remove mud and debris on the surface of the old dock. The side of the old dock facing the sea is the front side, and the side of the old dock facing the land is the rear side. A hydraulic breaker is used to break the upper rear end of the concrete block 11 of the old dock. After breaking, concrete is used for leveling to ensure the flatness of the upper rear end of the concrete block 11, so that a first groove is formed at the upper rear end of the concrete block 11, and the first groove is L-shaped.

[0061] Furthermore, after step S1, the method further includes:

[0062] S11, dismantling the fender piles 17 and the old fender 18 on the old dock;

[0063] S12. Install a number of rubber fenders 71 at the front end of the concrete block 11 of the old dock, and install a number of mooring posts 72 at the upper end thereof.

[0064] In the above steps S11 and S12, the fender piles 17 are cut underwater to the mud surface level, and the old fenders 18 are cut off. A handheld electric drill is used to drill holes on the surface of the concrete block 11 and pre-embed screws, and concrete is poured to install the mooring column 72 above the concrete block 11. A handheld electric drill is used to drill holes on the front end of the concrete block 11 and pre-embed screws, and concrete is poured to install the rubber fender 71.

[0065] In the above step S2, a hydraulic breaker is used to remove the surface layer 16, the first filling layer 15 and the vertical beam 14 on the top of the middle panel 13 of the old wharf, and the broken waste is loaded onto a dump truck by a hook machine and transported away, leaving the flat middle panel 13 of the old wharf, and the middle panel 13 of the old wharf is used as the construction platform for the subsequent cast-in-place piles 4.

[0066] In the above step S3, a rope saw is used to open multiple through holes from top to bottom on the top of the middle panel 13 of the old wharf. The positions of the through holes should avoid the foundation piles of the old wharf to prevent conflicts between the new and old pile positions and affect the construction of the newly constructed cast-in-place piles 4. The through holes are square holes, and the diameter of the through holes needs to be larger than the diameter of the steel casing of the cast-in-place piles 4 to be constructed later. Preferably, the diameter of the through holes is 15 cm larger than the diameter of the steel casing of the cast-in-place piles 4 to be constructed later. Then, at the position corresponding to each through hole, the middle panel 13 of the old wharf is used as a construction platform, and the cast-in-place piles 4 are constructed on the middle panel 13 of the old wharf.

[0067] Furthermore, in step S3, the construction steps of the cast-in-place pile 4 include:

[0068] Bury casing → drill holes → install steel cage → clean holes → pour concrete.

[0069] Casing burial: for each through hole, use a crane to lift the casing, raise the segmented casing, extend the casing from the top of the through hole into the through hole, and sink it from the corresponding through hole. The cross-sectional size of the casing is smaller than the size of the through hole, and the center of the casing cross section is located at the center of the through hole; when the casing is close to the ground, adjust the verticality and naturally lower it into the ground; with the assistance of an air suction mud machine, use a vibrating hammer to vibrate the casing to the designed depth; during the sinking process of the casing, take measures to clamp the guide groove steel to ensure that the casing is vertical. The subsequent casing length is determined based on the welding on the fixed casing. When the casing is sunk to the designed depth, the bottom elevation of the casing should be deeper than the bottom elevation of the soft soil foundation by twice the diameter of the steel casing.

[0070] Drilling: Use a drilling rig to impact a hole. When drilling a hole, put a certain amount of clay in the casing according to the designed ratio and fill it with clean water. Use low hammer dense impact to keep the mud surface in the hole stable. After drilling to 1 meter below the blade foot, drill at a normal speed according to the formation conditions. If a deviated hole is found during the drilling process, the stone flakes should be backfilled to 300-500mm above the deviated hole, and then the hole should be re-punched. When encountering boulders, use high and low strokes to impact alternately to break the large boulders or hit them into the hole wall. Check the hole every 4-5 meters of drilling depth, and check the hole before replacing the drill bit or at places where the hole is prone to shrinkage. After entering the bedrock, the hole should be emptied and sampled every time a certain depth is drilled in preparation for final hole acceptance. During the drilling process, the mud surface in the hole must be kept higher than the water surface outside the hole to ensure the quality of the drilling and prevent the occurrence of phenomena such as hole collapse.

[0071] Lifting the steel cage: Use a crane and a loader to transport it to the platform hole, lift it with a crawler crane, lower the steel cage, and position it according to the center of the pile. Use steel bars or steel sections for positioning. To prevent the steel cage from deforming too much, add a cross brace during processing, and weld two stirrups at the lifting position. When transporting it to the platform, use a crawler crane to lift the flat steel cage vertically in the air to avoid dragging, squeezing and deforming the lower part of the steel cage. Because the pile hole is long, it is made in 2-3 sections and hoisted to the site for welding of the auxiliary bars at the hole to form a whole. During this process, attention should be paid to the vertical connection of the steel cage, and the welding operation should be carried out in strict accordance with relevant specifications.

[0072] Hole cleaning: After the steel cage is lowered, check the hole bottom elevation. If the hole bottom elevation is higher than the design elevation, or the hole collapses during the steel cage sinking process, the air lift reverse circulation hole cleaning process can be used to clean the hole. During the hole cleaning process, high-quality mud is added and the water head in the hole is maintained to prevent hole collapse. When the hole bottom elevation after cleaning meets the design requirements and the mud indicators are qualified, concrete pouring can be carried out. The air lift reverse circulation hole cleaning process uses compressed air from an air compressor to be delivered to the pile hole through an air duct installed in the conduit. The high-pressure air mixes with the mud to form a slurry-gas mixture with a density less than that of the mud in the conduit. The slurry-gas mixture rises due to its small specific gravity, forming a negative pressure at the bottom of the mixer in the conduit. The mud below rises under the action of the negative pressure, and is continuously replenished under the combined action of the air pressure momentum. The mud that rises to the mixer forms an air-slurry mixture with the gas and continues to rise, thus forming a flow. Because the inner cross-sectional area of ​​the conduit is much smaller than the annular cross-sectional area between the outer wall of the conduit and the pile wall, a reverse circulation with extremely high flow rate and flow is formed, carrying the sediment out of the conduit and discharging it outside the conduit.

[0073] Concrete pouring: Connect the ends of a conduit with a diameter of 300mm, a thickness of 5mm and a length of 3m in a single section and sink it to the bottom of the hole. The top of the conduit is suspended on the top of the steel casing with a buckle and an iron plate. A 5m3 funnel is inserted above the top section of the conduit. An inclined steel platform is set on the side of the funnel. The mixer truck retreats to the top of the steel platform, and the side unloading plate of the mixer truck is opened manually. The concrete will be unloaded from the mixer truck to the funnel. The concrete in the hole is poured into the borehole along the conduit. After unloading the concrete of one mixer truck, another mixer truck can be connected until the concrete is poured to the top of the steel casing. During the pouring process, the conduit needs to be lifted from time to time to ensure that the depth of the buried conduit under the concrete is 2-6m to prevent the conduit from being pulled up due to excessive full depth. After the concrete in the casing solidifies, a cast-in-place pile 4 is formed.

[0074] Please refer to Figure 7 , Figure 7 The pile position arrangement diagram of the cap section in the hybrid structure of the old wharf expansion and reconstruction structure of the present invention. Further, after the construction is completed, the multiple cast-in-place piles 4 are divided into four rows, and the four rows of cast-in-place piles 4 are arranged at equal intervals along the land toward the sea. Since there is a gap between the bottom of the front end of the new wharf 2 and the concrete block 11, it is a cantilever structure. The pile foundation bearing capacity required at the front end of the new wharf 2 is higher, so the pile diameter of the row of cast-in-place piles 4 closest to the sea side among the four rows of cast-in-place piles 4 is greater than the pile diameters of the remaining cast-in-place piles 4. Preferably, the pile diameter of the row of cast-in-place piles 4 closest to the sea side among the four rows of cast-in-place piles 4 is 1.2m, and the pile diameters of the remaining cast-in-place piles 4 are 1m. At the same time, to ensure that the bearing capacity of the cast-in-place piles meets the requirements, the pile tips of the row of cast-in-place piles 4 closest to the sea side among the four rows of cast-in-place piles 4 penetrate the soft soil layer and enter the hard soil layer by no less than 8 times its pile diameter, and the pile tips of the remaining cast-in-place piles 4 penetrate the soft soil layer and enter the hard soil layer by no less than 5 times its pile diameter.

[0075] In the above step S4, a hydraulic breaker is used to gradually break the middle panel 13 of the old wharf along the length direction of the old wharf, and a hook machine is used to knock down the foundation piles and pile caps of the old wharf to ensure that the top elevation of the foundation piles of the old wharf after being broken does not affect the subsequent construction of the support system 9.

[0076] In the above step S5, a new wharf 2 is built on the top of the cast-in-place pile 4. After the construction of the new wharf 2 is completed, the top of the cast-in-place pile 4 is inserted into the new wharf 2 by no less than 10 cm. A drainage trough 22 is provided on the surface of the new wharf 2 near its front end. The bottom of the drainage trough 22 is connected to the bottom of the new wharf 2 through multiple drainage pipes 23. Preferably, multiple drainage pipes 23 connected to the drainage trough 22 are divided into multiple drainage pipe groups in pairs. Multiple drainage pipe groups are arranged at intervals along the length direction of the drainage trough 22, and the drainage pipe 23 is a UPVC pipe. A floor drain is provided on the surface of the new wharf 2 near its rear end. The floor drain is connected to the bottom of the new wharf 2 through the drainage trough 22 and the drainage pipe 23. Multiple floor drains are arranged, and multiple floor drains are arranged at equal intervals along the length direction of the new wharf. The accumulated water on the surface of the new wharf 2 flows to the bottom of the new wharf 2 through the drainage trough 22 and the drainage pipe 23, or flows to the bottom of the new wharf 2 through the floor drain and the drainage pipe 23. The floor drain can prevent debris from clogging the drainage pipe 23. Preferably, a fence cover is provided at the top opening of the drainage trough 22 to facilitate the operation of upper vehicles and prevent debris from falling into the drainage trough 22. Furthermore, the surface of the newly built dock 2 gradually slopes downward from a position near its rear end to its front and rear sides, so that the accumulated water on the surface of the newly built dock 2 flows into the drainage structures on its front and rear sides to meet the drainage needs of the newly built dock 2.

[0077] A buffer plate 5 is arranged between the front end of the newly built dock 2 and the first groove, and there is a gap between the bottom of the buffer plate 5 and the first groove, so that the newly built dock 2 forms a cantilever structure, and the operating load above the newly built dock 2 will not be transferred to the concrete blocks 11 of the old dock, which can effectively ensure the stability of the concrete blocks 11 of the old dock. When the concrete blocks 11 of the old dock are squeezed by the docked ships, part of the force can be transferred to the newly built dock 2 behind through the buffer plate 5. On the one hand, the coordination and consistency between the concrete blocks 11 of the old dock and the newly built dock 2 are ensured, and the displacement between the two is reduced or even avoided to buffer the displacement between different structures. On the other hand, the bearing capacity of the newly built dock 2 is fully utilized, and the force on the concrete blocks 11 of the old dock is effectively relieved, thereby increasing the bearing capacity of the dock as a whole, and further avoiding the force damage between the newly built dock 2 and the concrete blocks 11. Preferably, the buffer plate 5 is a foam board. Furthermore, the newly built wharf 2 includes a beam-slab structure section 61, a pier structure section 61 and a new wharf surface layer, the front end of the beam-slab structure section 61 is connected to the pier structure section 61, and includes a longitudinal beam and a plurality of transverse beams, the longitudinal beam is connected to the plurality of transverse beams, and the length direction of the longitudinal beam is perpendicular to the length direction of the transverse beams, the plurality of transverse beams are arranged in parallel with each other, and a second filling layer is arranged between two adjacent transverse beams, and the new wharf surface layer is arranged on the beam-slab structure section 61 and the pier structure section 61. Preferably, the rear end of the pier structure section 61 is inclined from bottom to top toward the land side to form an inclined surface, and the front end of the transverse beam is adapted to the rear end of the pier structure.

[0078] Please refer to Figure 6 , Figure 6 The schematic diagram of the support system of the new dock in the hybrid structure of the old dock expansion structure of the present invention. Further, in step S5, the new dock 2 is built on the top of the cast-in-place pile 4, and a buffer plate 5 is set between the front end of the new dock 2 and the first groove, and the construction steps of the buffer plate 5 having a gap between the bottom and the first groove include:

[0079] S51, laying a sand cushion layer 8 at the bottom of the first groove;

[0080] S52, except for a row of cast-in-place piles 4 on the side closest to the land, a support system 9 is installed on the upper part of the remaining cast-in-place piles 4, wherein the support system 9 includes a corbel 91 welded to the cast-in-place piles 4, a load-relief block 92 and a support beam 93 are sequentially arranged on the corbel 91, a main beam 94 is erected on the support beam 93, a transfer beam 95 and a wooden beam 96 are arranged on the main beam 94 at intervals, a wooden template 97 is laid above the transfer beam 95 and the wooden beam 96, and the bottom surface of one end of the wooden template 97 abuts against the surface of the sand cushion layer 8;

[0081] S53, dumping stones on the revetment structure 3 to form a block stone bottom formwork 98, laying a first concrete cushion layer 99 on the block stone bottom formwork 98 at the rear side of the wooden formwork 97, the first concrete cushion layer 99 and the top elevation of the wooden formwork 97 being consistent, and the two are connected to form a bottom formwork;

[0082] S54, installing a buffer plate 5 on the side wall of the first groove, pouring concrete on the bottom formwork, and after the concrete reaches the designed curing period, removing the support system 9 and the sand cushion layer 8, thereby forming a new wharf 2.

[0083] In the above steps S51 to S54, a sand cushion layer 8 is laid at the bottom of the first groove, and the thickness of the sand cushion layer 8 is the spacing distance between the bottom of the newly built wharf 2 and the first groove. Then, except for a row of cast-in-place piles 4 on the side closest to the land, brackets 91 are symmetrically welded on the upper part of the remaining cast-in-place piles 4. Furthermore, in order to ensure the bearing capacity of the brackets 91, diagonal braces are welded between the brackets 91 and the steel casings of the cast-in-place piles 4. A load-relief block 92 is spot-welded on each corbel 91 to ensure that no displacement occurs during the concrete pouring process of the new wharf 2. The support beam 93 is located above the load-relief block 92, and the length direction of the support beam 93 is consistent with the connection direction of each row of cast-in-place piles 4. The main beam 94 is located above the support beam 93, and the length direction of the main beam 94 is perpendicular to the length direction of the support beam 93. Above the main beam 94, the transfer beam 95 and the wooden beam 96 are staggered, and the length direction of the two is consistent with the length direction of the support beam 93. Finally, a wooden formwork 97 is placed above the transfer beam 95 and the wooden beam 96. The silt layer on the revetment structure 3 is removed, and stones are dumped on the revetment structure 3 around the row of cast-in-place piles 4 on the side closest to the land to form a block stone bottom formwork 98. The dumped stones can be stones excavated from the top of the revetment structure 3. A first concrete cushion layer 99 is laid on the position of the block stone bottom formwork 98 located at the rear side of the wooden template 97. The first concrete cushion layer 99 is consistent with the top elevation of the wooden template 97, and the two are connected to form a bottom template. After the subsequent retaining wall 6 and the newly built wharf 2 are constructed, a closed space is formed between the retaining wall 6, the newly built wharf 2 and the revetment structure 3. Therefore, the support system 9 is used in the row of cast-in-place piles 4 on the side closest to the land, and it cannot be removed after the concrete is poured, which increases the construction cost. Therefore, using dumped stones as the block stone bottom formwork 98 can greatly save the one-time use cost of the support system 9. After the rear support system 9 is installed, a buffer plate 5 is installed on the side wall of the first groove of the concrete block 11, so that after the pouring of the newly built wharf 2 is completed, there is a buffer plate 5 between the front end of the newly built wharf 2 and the first groove. Then, concrete is poured on the bottom formwork. The concrete pouring process is an existing technology and will not be described in detail here. After the concrete reaches the designed curing period, the support system 9 is removed, and the sand cushion layer 8 is washed out by a high-pressure water gun, thereby forming a new dock 2, and a buffer plate 5 is provided between the front end of the new dock 2 and the first groove, and there is a gap between the bottom of the new dock 2 and the first groove.

[0084] Furthermore, in the process of constructing the new wharf 2, the construction can be carried out in sections, that is, the new wharf 2 is divided into multiple platform sections 21 for construction. A protrusion 211 is provided at one end of the platform section 21, and a second groove 212 is provided at the other end. The protrusion 211 and the second groove 212 are matched. A buffer plate 5 is provided between two adjacent platform sections 21, which can form the entire new wharf 2 into a whole, reduce the displacement of the wharf when large-tonnage ships berth and moor, and improve the horizontal resistance, which can greatly improve the horizontal resistance of the wharf. A buffer plate 5 is provided between two adjacent platform sections 21, which can effectively prevent the collision between different platform sections 21 under the action of wind, waves and currents, causing the concrete to fall off, thereby ensuring the quality of the new wharf 2.

[0085] Furthermore, in step S54, the construction steps of dismantling the support system 9 include:

[0086] S541, before pouring concrete on the bottom formwork, for each cast-in-place pile 4 within the range of the wooden formwork 97, a plurality of embedded pipes 910 are arranged around the cast-in-place pile 4, the top elevation of the embedded pipe 910 is consistent with the top elevation of the newly built wharf 2, and the bottom thereof passes through the wooden formwork 97;

[0087] S542, after the concrete poured on the bottom formwork reaches the designed curing period, for each embedded pipe, use a steel wire rope to pass through the embedded pipe 910 and pull the corresponding support beam 93;

[0088] S543, remove the unloading block 92 and the corbel 91, lower the support beam 93, the main beam 94, the transfer beam 95 and the wooden beam 96 to the floating raft through the steel wire rope, and remove the wooden formwork 97.

[0089] In the above steps S541 to S543, for each cast-in-place pile 4 within the range of the wooden formwork 97, four embedded pipes 910 are arranged around the cast-in-place pile 4, the embedded pipes 910 are fixed to the upper steel bars by tying wires, and the bottom of the embedded pipes 910 passes through the wooden formwork 97. When the concrete pouring is completed and the support system 9 needs to be disassembled, for each embedded pipe 910, a steel wire rope is passed through the embedded pipe 910 and connected to the support beam 93 below, and the end of the steel wire rope away from the support beam 93 can be connected to a hand winch as a support point, and the hand winch is arranged on the newly built wharf 2, so that the support beam 93 is suspended by the steel wire rope. The unloading block 92 is knocked off manually with a hammer, the corbel 91 and the diagonal brace below are removed by welding, and then the support beam 93, the main beam 94, the transfer beam 95 and the wooden beam 96 are lowered onto the floating raft by lowering the wire rope through a hand winch to recycle the support beam 93, the main beam 94, the transfer beam 95 and the wooden beam 96, etc., to save construction costs, and finally the wooden formwork 97 is removed.

[0090] In the above step S6, retaining walls 6 are constructed on the left, right and rear sides of the newly built wharf 2. The newly built wharf 2 transfers part of the force to the retaining wall 6 at the rear through the buffer plate 5, reducing or even avoiding the displacement between the two, so as to buffer the displacement between different structures. On the other hand, the bearing capacity of the newly built wharf 2 is fully utilized, and the force on the newly built wharf 2 is effectively alleviated, thereby increasing the overall bearing capacity of the wharf and further avoiding force damage between the newly built wharf 2 and the retaining wall 6.

[0091] Further, in step S6, a retaining wall 6 is constructed at the rear side of the newly built wharf 2, and a buffer plate 5 is provided between the retaining wall 6 and the newly built wharf 2. The construction steps include:

[0092] S61, digging construction trenches at the positions of the revetment structure 3 on the left side, right side and rear side of the newly built wharf 2;

[0093] S62, filling the crushed stone cushion layer 31 and pouring the second concrete cushion layer 32 in the construction trench in sequence;

[0094] S63, installing buffer plates 5 at the left end, the right end and the rear end of the newly built dock 2;

[0095] S64, constructing a retaining wall 6 on the second concrete cushion layer 32;

[0096] S65, constructing the backfill sand layer 33 and the road surface layer 34 in the construction trench in sequence.

[0097] In the above steps S61 to S65, a construction trench is dug at the top of the revetment structure 3 at the left, right and rear sides of the newly built wharf 2. The stones excavated from the revetment structure 3 can be used as the filling materials of the block bottom mold 98 when pouring the newly built wharf 2. The crushed stone cushion layer 31 is filled in the construction trench. The thickness of the crushed stone cushion layer 31 is 30 cm. The crushed stone with a particle size of 30-150 mm is used. After the filling is completed, the back of the long-arm hook hopper is compacted and the flat plate rammer is used for secondary compaction to prevent the subsequent settlement of the retaining wall 6. Then the second concrete cushion layer 32 is poured. The thickness of the second concrete cushion layer 32 is 10 cm. After the second concrete cushion layer 32 is poured, the buffer plate 5 is installed at the left end, right end and rear end of the newly built wharf 2 so that the current and the newly built wharf 2 are connected through the buffer plate 5. Then the retaining wall 6 is poured on the second concrete cushion layer 32. The retaining wall 6 is poured in layers, and the thickness of a single layer does not exceed 50 cm. After the retaining wall 6 is poured, a backfill sand layer 33 is constructed in the space between the retaining wall 6 and the construction trench. The backfill sand layer 33 is compacted by flushing water and vibrating with a vibrating rod. The road surface layer 34 is a reinforced concrete structure with a thickness of 20 cm. Furthermore, the retaining wall 6 can be constructed in sections, that is, the retaining wall 6 is divided into multiple structural sections 61 for construction, and a buffer plate 5 is provided between two adjacent structural sections 61.

[0098] The present invention also provides a mixed-structure old dock reconstruction and expansion structure, including a concrete block 11 of the old dock, a new dock 2 arranged at the rear side of the concrete block 11, and a revetment structure 3 arranged below the new dock 2. A plurality of cast-in-place piles 4 are arranged at the bottom of the new dock 2, a first groove is arranged at the upper rear side of the concrete block 11, a buffer plate 5 is arranged between the front end of the new dock 2 and the first groove, a space is arranged between the bottom of the new dock 2 and the first groove, retaining walls 6 are respectively arranged on the left side, right side and rear side of the new dock 2, the retaining wall 6 is arranged in the revetment structure 3, and a buffer plate 5 is arranged between the retaining wall 6 and the new dock 2.

[0099] The hybrid structure of the old dock reconstruction and expansion structure of the present invention retains the concrete blocks 11 and the revetment structure 3 of the old dock, only the old dock structure behind the concrete blocks 11 is demolished, and a new dock 2 and cast-in-place piles 4 are built on the original site of the old dock. The concrete blocks 11 of the existing old dock are used as the main body to bear the upper operating load, which can save a lot of time and cost. The new dock 2 adopts a cantilever structure, and there is a gap between it and the concrete blocks 11. The operating load above the new dock 2 will not be transferred to the concrete blocks 11 of the old dock, which can effectively ensure the stability of the concrete blocks 11 of the old dock; the new dock 2 is connected to the concrete blocks 11 through the buffer plate 5 1 and the retaining wall 6. When the concrete blocks 11 of the old wharf are subjected to the squeezing force of the docked ships, the buffer plate 5 can transfer part of the force to the newly built wharf 2 behind, and the newly built wharf 2 transfers part of the force to the retaining wall 6 behind. On the one hand, the coordination and consistency between the concrete blocks 11 of the old wharf and the newly built wharf 2 are ensured, and the displacement between the two is reduced or even avoided to buffer the displacement between different structures. On the other hand, the bearing capacity of the newly built wharf 2 is fully utilized to effectively relieve the force on the concrete blocks 11 of the old wharf, thereby increasing the bearing capacity of the wharf as a whole and further avoiding the force damage between the newly built wharf 2 and the concrete blocks 11. Preferably, the buffer plate 5 is a foam board.

[0100] In one embodiment, the newly built dock 2 includes a plurality of capping sections 21 connected in sequence, one end of the capping section 21 is provided with a protrusion 211, and the other end is provided with a second groove 212, the protrusion 211 and the second groove 212 are matched, and a buffer plate 5 is provided between two adjacent capping sections 21. The protrusion 211 and the second groove 212 are matched between the two adjacent capping sections 21, so that the entire newly built dock 2 can be formed as a whole, reducing the displacement of the dock when large-tonnage ships are berthed and moored, and improving the horizontal resistance, which can greatly improve the horizontal resistance of the dock. The buffer plate 5 is provided between the two adjacent capping sections 21, which can effectively prevent the collision between different capping sections 21 under the action of wind, waves, and currents, resulting in the problem of concrete falling off, thereby ensuring the quality of the newly built dock 2. In one embodiment, the newly built wharf 2 includes a beam-slab structure section 61, a pier structure section 61 and a wharf surface layer, the front end of the beam-slab structure section 61 is connected to the pier structure section 61, and it includes a longitudinal beam and a plurality of transverse beams, the longitudinal beam is connected to the plurality of transverse beams, and the length direction of the longitudinal beam is perpendicular to the length direction of the transverse beams, the plurality of transverse beams are arranged in parallel with each other, and a second filling layer is arranged between two adjacent transverse beams, and the wharf panel 13 is arranged on the beam-slab structure section 61 and the pier structure section 61. Preferably, the rear end of the pier structure section 61 is inclined from bottom to top toward the land side to form an inclined surface, and the front end of the transverse beam is adapted to the rear end of the pier structure.

[0101] The pile foundation of the newly built wharf 2 adopts cast-in-place piles 4, which can ensure the stability of the newly built wharf 2 and reduce the settlement of the wharf under various mechanical loads during the operation stage; further, the multiple cast-in-place piles 4 are divided into four rows, and the four rows of cast-in-place piles 4 are arranged at equal intervals along the land toward the sea. Since there is a gap between the bottom of the front end of the newly built wharf 2 and the concrete block 11, it is a cantilever structure. The pile foundation bearing capacity required at the front end of the newly built wharf 2 is higher, so the pile diameter of the row of cast-in-place piles 4 closest to the sea side among the four rows of cast-in-place piles 4 is greater than the pile diameters of the remaining cast-in-place piles 4. Preferably, the pile diameter of the row of cast-in-place piles 4 closest to the sea side among the four rows of cast-in-place piles 4 is 1.2m, and the pile diameters of the remaining cast-in-place piles 4 are 1m. At the same time, in order to ensure that the pile bearing capacity meets the requirements, the pile tips of the row of cast-in-place piles 4 closest to the sea side among the four rows of cast-in-place piles 4 penetrate the soft soil layer and enter the hard soil layer by no less than 8 times its pile diameter, and the pile tips of the remaining cast-in-place piles 4 penetrate the soft soil layer and enter the hard soil layer by no less than 5 times its pile diameter.

[0102] Furthermore, the revetment structure 3 is provided with construction trenches at the left, right and rear sides of the newly built wharf 2, and a crushed stone cushion layer 31 is provided in the construction trench, and a second concrete cushion layer 32 is provided on the crushed stone cushion layer 31, and the retaining wall 6 is provided on the second concrete cushion layer 32, and a backfill sand layer 33 and a road surface layer 34 are filled between the retaining wall 6 and the inner wall of the construction trench, and the road surface layer 34 is provided on the backfill sand layer 33. The newly built wharf 2 transfers part of the force to the retaining wall 6 at the rear, reducing or even avoiding the displacement between the two, so as to buffer the displacement between different structures, and on the other hand, gives full play to the bearing capacity of the newly built wharf 2, effectively alleviates the force on the newly built wharf 2, thereby increasing the bearing capacity of the wharf as a whole, and further avoiding the force damage between the newly built wharf 2 and the retaining wall 6. Preferably, the crushed stone cushion layer 31 is 30 cm thick, and crushed stones with a particle size of 30-150 mm are used, the second concrete cushion layer 32 is 10 cm thick, and the retaining wall 6 is cast in layers, and the thickness of a single layer does not exceed 50 cm. In one embodiment, the retaining wall 6 includes a plurality of structural segments 61 , and a buffer plate 5 is disposed between two adjacent structural segments 61 .

[0103] In one embodiment, a drainage trough 22 is provided near the front end of the surface of the newly built dock 2, and the bottom of the drainage trough 22 is connected to the bottom of the newly built dock 2 through multiple drainage pipes 23, and / or a floor drain is provided near the rear end of the surface of the newly built dock 2, and the floor drain is connected to the bottom of the newly built dock 2 through the drainage trough 22 and the drainage pipe 23. The accumulated water on the surface of the newly built dock 2 flows to the bottom of the newly built dock 2 through the drainage trough 22 and the drainage pipe 23, or flows to the bottom of the newly built dock 2 through the floor drain and the drainage pipe 23. The floor drain can prevent debris from clogging the drainage pipe 23. In one embodiment, a fence cover is provided at the top opening of the drainage trough 22. The fence cover is provided for the operation of upper vehicles to prevent debris from falling into the drainage trough 22. In one embodiment, the surface of the newly built dock 2 gradually slopes downward from the position near the rear end to the front and rear sides thereof. The accumulated water on the surface of the newly built dock 2 flows to the drainage structures on the front and rear sides thereof to meet the drainage needs of the surface of the newly built dock 2.

[0104] In one embodiment, a plurality of rubber fenders 71 are provided at the front end of the concrete block 11, and a plurality of mooring posts 72 are provided at the upper end thereof. New rubber fenders 71 and mooring posts 72 are replaced on the concrete block 11 to meet the berthing requirements of the ship.

[0105] Compared with the prior art, the beneficial effects of the present invention are as follows: the concrete blocks 11 of the existing old wharf are used as the main body to bear the upper operating load, and only the wharf part behind the concrete blocks 11 is demolished, which can save a lot of time and cost; the newly built wharf 2 adopts a cantilever structure, and there is a gap between it and the concrete blocks 11, so the operating load above the newly built wharf 2 will not be transmitted to the concrete blocks 11 of the old wharf, which can effectively ensure the stability of the concrete blocks 11 of the old wharf; the foundation piles adopt cast-in-place piles 4, which can ensure the stability of the newly built wharf 2 and reduce the settlement of the wharf under various mechanical loads during the operation stage; the newly built wharf 2 is connected to the concrete blocks 11 and the retaining wall 6 through the buffer plate 5. When the concrete blocks 11 of the old wharf are squeezed by the docked ships, the buffer plate 5 can be used to The punching plate 5 transfers part of the force to the newly built wharf 2 at the rear, and the newly built wharf 2 transfers part of the force to the retaining wall 6 at the rear. On the one hand, the coordination and consistency between the concrete blocks 11 of the old wharf and the newly built wharf 2 are ensured, and the displacement between the two is reduced or even avoided, so as to buffer the displacement between different structures. On the other hand, the bearing capacity of the newly built wharf 2 is fully utilized, and the force on the concrete blocks 11 of the old wharf is effectively alleviated, thereby increasing the overall bearing capacity of the wharf, and further avoiding the force damage between the newly built wharf 2 and the concrete blocks 11. The present invention improves the construction efficiency of the reconstruction and expansion of the old wharf, shortens the construction period, ensures the quality of the newly built wharf 2 after reconstruction and expansion, reduces the settlement of the wharf during the operation stage, ensures the quality of the wharf operation, and shortens the time of interruption of the wharf operation due to reconstruction.

[0106] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Therefore, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A construction method for reconstruction and expansion of an old mixed-structure wharf, characterized in that: The following steps are involved: The upper rear end of the concrete block of the old dock is broken and leveled to form the first groove; Removing the surface layer, the first filling layer and the vertical beams on the top of the middle panel of the old wharf to expose the middle panel of the old wharf flatly; A plurality of through holes for the construction of cast-in-place piles are opened on the middle panel of the old wharf, and cast-in-place piles are constructed at positions corresponding to each of the through holes; dismantling the middle panel of the old pier and breaking the old pier foundation piles below the middle panel of the old pier; A new wharf is constructed on the top of the cast-in-place pile, a buffer plate is arranged between the front end of the new wharf and the first groove, and a gap exists between the bottom of the buffer plate and the first groove; Retaining walls are respectively constructed on the left side, right side and rear side of the newly built wharf, and a buffer plate is arranged between the retaining walls and the newly built wharf.

2. The hybrid structure old dock reconstruction and expansion construction method according to claim 1 is characterized in that: The plurality of cast-in-place piles are divided into four rows, and the four rows of cast-in-place piles are arranged at equal intervals from the land toward the sea area. The construction steps of building a new wharf on the top of the cast-in-place piles, arranging a buffer plate between the front end of the new wharf and the first groove, and having a gap between the bottom of the buffer plate and the first groove include: Laying a sand cushion layer at the bottom of the first groove; Except for a row of the cast-in-place piles on the side closest to the land, a support system is installed on the upper part of the remaining cast-in-place piles, wherein the support system includes a corbel welded to the cast-in-place piles, a load-relief block and a support beam are sequentially arranged on the corbel, a main beam is erected on the support beam, a transfer beam and a wooden beam are arranged on the main beam at intervals, a wooden template is laid above the transfer beam and the wooden beam, and the bottom surface of one end of the wooden template abuts against the surface of the sand cushion layer; Throwing stones on the revetment structure to form a block stone bottom formwork, laying a first concrete cushion layer on the block stone bottom formwork at the rear side of the wooden formwork, wherein the first concrete cushion layer has the same elevation as the top of the wooden formwork, and the two are connected to form a bottom formwork; A buffer plate is installed on the side wall of the first groove, and concrete is poured on the bottom formwork. After the concrete reaches the designed curing period, the support system and the sand cushion layer are removed to form the newly built wharf.

3. The hybrid structure old dock reconstruction and expansion construction method according to claim 2 is characterized in that: The construction steps of dismantling the support system include: Before pouring concrete on the bottom formwork, for each bored pile within the range of the wooden formwork, a plurality of embedded pipes are arranged around the bored pile, the top elevation of the embedded pipes being consistent with the top elevation of the newly built wharf, and the bottom of the embedded pipes passing through the wooden formwork; After the concrete poured on the bottom formwork reaches the designed curing period, for each embedded pipe, a steel wire rope is passed through the embedded pipe and pulls the corresponding support beam; The unloading blocks and corbels are removed, and the supporting beams, main beams, transfer beams and wooden beams are lowered onto the floating raft by steel wire ropes, and the wooden formwork is removed.

4. The hybrid structure old dock reconstruction and expansion construction method according to claim 2 is characterized in that: The pile diameter of the row of cast-in-place piles closest to the sea area among the four rows is larger than the pile diameters of the other cast-in-place piles, and / or the pile tips of the row of cast-in-place piles closest to the sea area among the four rows enter the hard soil layer at least 8 times its pile diameter, while the pile tips of the other cast-in-place piles enter the hard soil layer at least 5 times its pile diameter.

5. The hybrid structure old dock reconstruction and expansion construction method according to claim 1 is characterized in that: The construction steps of building a retaining wall at the rear side of the newly built wharf and setting a buffer plate between the retaining wall and the newly built wharf include: Dig construction trenches at the locations where the revetment structure is located on the left, right and rear sides of the new pier; sequentially filling a crushed stone cushion layer and pouring a second concrete cushion layer in the construction trench; Installing buffer plates at the left end, the right end and the rear end of the newly built wharf; constructing a retaining wall on the second concrete cushion layer; A backfill sand layer and a road surface layer are sequentially constructed in the construction trench.

6. The hybrid structure old dock reconstruction and expansion construction method according to claim 1 is characterized in that: The construction steps of the cast-in-place pile include: Bury casing → drill holes → install steel cage → clean holes → pour concrete.

7. The hybrid structure old dock reconstruction and expansion construction method according to claim 1 is characterized in that: After the step of breaking and leveling the upper rear end of the concrete block of the old wharf, the method further comprises: removing the fender sheet piles and old fenders on said old dock; A plurality of rubber fenders are installed at the front end of the concrete block of the old wharf, and a plurality of mooring posts are installed at the upper end thereof.

8. A hybrid structure for the reconstruction and expansion of an old dock, characterized in that: The invention comprises a concrete block of an old wharf, a new wharf arranged at the rear side of the concrete block, and a revetment structure arranged under the new wharf, wherein a plurality of cast-in-place piles are arranged at the bottom of the new wharf, the plurality of cast-in-place piles are divided into four rows, and the four rows of cast-in-place piles are arranged at equal intervals along the land toward the sea area, the pile diameter of a row of cast-in-place piles closest to the sea area among the four rows of cast-in-place piles is larger than the pile diameters of the other cast-in-place piles, a first groove is arranged at the upper rear side of the concrete block, a buffer plate is arranged between the front end of the new wharf and the first groove, a gap is arranged between the bottom of the new wharf and the first groove, retaining walls are arranged on the left side, right side and rear side of the new wharf respectively, construction grooves are arranged at the positions of the revetment structure located at the left side, right side and rear side of the new wharf respectively, a crushed stone cushion layer is arranged in the construction groove, a concrete cushion layer is arranged on the crushed stone cushion layer, the retaining wall is arranged on the concrete cushion layer, a backfill sand layer and a road surface layer are filled between the retaining wall and the inner wall of the construction groove, the road surface layer is arranged on the backfill sand layer, and a buffer plate is arranged between the retaining wall and the new wharf.

9. The hybrid structure old dock reconstruction and expansion structure according to claim 8 is characterized in that: The newly built wharf includes a plurality of pedestal sections connected in sequence, one end of the pedestal section is provided with a protrusion, and the other end is provided with a second groove, the protrusion and the second groove are matched with each other, a buffer plate is provided between two adjacent pedestal sections, and / or the retaining wall includes a plurality of structural sections, and a buffer plate is provided between two adjacent structural sections.

10. The hybrid structure of the old dock reconstruction and expansion structure according to claim 8, characterized in that: A drainage ditch is provided on the surface of the newly built dock near its front end, and the bottom of the drainage ditch is connected to the bottom of the newly built dock through a plurality of drainage pipes. A fence cover is provided at the top opening of the drainage ditch, and / or a floor drain is provided on the surface of the newly built dock near its rear end, and the floor drain is connected to the bottom of the newly built dock through a drainage pipe.

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