Combined immersed deep-water double-wall steel cofferdam and its construction method

Abstract

The present invention relates to a combined immersed deep-water double-wall steel cofferdam and its construction method, which adopts the technology of auxiliary overall lowering of the steel cofferdam by steel casing; adopts the technology of temporary steel cofferdam plate for anti-scouring of the dredged sand riverbed; adopts the technology of correcting deviation by partial load with high-side water injection; and adopts the technology of lowering the cofferdam by dredged sand at the bottom. Its main construction steps include: 1) erection and assembly of the steel cofferdam assembly platform; 2) installation of the temporary anti-scouring steel cofferdam plate of the cofferdam; 3) lowering of the cofferdam in water; 4) lowering of the cofferdam by dredged sand; 5) recovery of the temporary anti-scouring steel cofferdam plate; 6) deviation correction by partial load with high-side water injection. The deep-water double-wall steel cofferdam improves the overall lowering speed of the steel cofferdam, ensures the rapid demolition and recovery of the temporary anti-scouring steel cofferdam plate, and realizes the effect of correcting the deviation of the cofferdam.

Description

Technical Field

[0001] The present invention relates to the construction of a deep - water double - wall steel cofferdam, and particularly to a combined sinking deep - water double - wall steel cofferdam and its construction method. Background Technique

[0002] At the present stage, the construction of expressways in China is continuously advancing, and there are more and more deep - water bridge projects across rivers, lakes, etc. In practice, double - wall steel cofferdams are commonly used for the construction of bridge foundations in deep - water areas. Due to the complex water level and geological conditions in deep - water areas such as rivers and lakes, if the construction method is unreasonable, the construction process is not scientifically arranged, and the construction supervision is ineffective, there may be deviations in the sinking position of the bridge foundation, which will affect the construction safety and quality. Moreover, during the construction of the steel cofferdam, it is found that especially for the sinking of the cofferdam in a sand - blowing riverbed, due to the weak anti - erosion ability of the conventional steel cofferdam, it is easy to cause a large deviation in the landing of the cofferdam. Therefore, how to innovate and improve the construction technology of the steel cofferdam is a key factor in the construction of large - scale deep - water double - wall steel cofferdams.

[0003] In summary, it is of great significance to seek a combined sinking deep - water double - wall steel cofferdam and its construction method with high construction efficiency, low construction cost, and simple operation. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a combined sinking deep - water double - wall steel cofferdam and its construction method.

[0005] To achieve the above - mentioned technical purpose, the present invention adopts the following technical solutions:

[0006] The construction method of the present combined sinking deep - water double - wall steel cofferdam includes the following steps:

[0007] Step 1: Erection and assembly of the steel cofferdam assembly platform:

[0008] Precisely position the cofferdam wall using the assembly platform and perform the assembly of the cofferdam.

[0009] Step 2: Installation of the temporary anti - erosion steel sheeting for the cofferdam:

[0010] Install the temporary anti - erosion steel sheeting on the assembled cofferdam to reduce the impact of riverbed erosion on the cofferdam during construction.

[0011] Step 3: Sinking of the cofferdam in water:

[0012] After the assembly of each section of the cofferdam wall is completed, use the jacking system to lift the steel cofferdam, retract the corbel supports of the assembly platform, and then sink the cofferdam. By evenly injecting water into the cofferdam's compartment and pouring the concrete for the cutting edge, the cofferdam can overcome the buoyancy and sink.

[0013] Step 4: Sinking of the cofferdam by sand blowing:

[0014] After the cutting edge of the cofferdam enters the riverbed and the cutting edge concrete is poured, sand flushing and sinking are carried out;

[0015] Step Five: Recycling of the temporary anti-erosion steel bulkhead:

[0016] After the steel cofferdam is sunk, cooperate with the jack lowering system to lift it, and combine with the upward pull of the suspension rod to quickly remove and recycle the temporary anti-erosion steel bulkhead;

[0017] Step Six: Rectifying deviation by injecting water on the high side and applying eccentric ballast:

[0018] Deviation correction is carried out by adjusting the weight distribution on both sides of the cofferdam.

[0019] Furthermore, in Step One, the bracket supports of the assembly platform are installed on the steel casing, and a U-shaped limiting device is set on the steel casing to accurately position the cofferdam wall body;

[0020] After the assembly of each section of the cofferdam wall body is completed, use the jack lowering system to lift the steel cofferdam, remove the screw rods at both ends by rotating the rotating nuts, make the connecting block move along the direction of the shortening of the spring rod, and use the rotating shaft to reduce the angle between the cross brace and the column to achieve the purpose of rapid contraction of the bracket support.

[0021] Furthermore, in Step One, the bracket support consists of a cross brace, a column and a telescopic diagonal brace to form a frame structure, and the screw rod provided with a support plate is connected by a rotating nut to strengthen the structural stability; both ends of the telescopic diagonal brace are provided with connecting blocks respectively connected to the spring rods inside the cross brace and the column; the U-shaped limiting device is placed on the bearing plate, the top plate is welded to the left end thereof, and a sliding groove is formed at the bottom to install the limiting plate.

[0022] Furthermore, in Step One, the cofferdam wall body is placed between the limiting plate and the right vertical plate of the U-shaped groove, and the relative distance between the limiting plate and the right vertical plate of the U-shaped groove is adjusted by the jack for the assembly of the cofferdam.

[0023] Furthermore, in Step Two, the specific measures for installing the temporary anti-erosion steel bulkhead are as follows:

[0024] Place the cofferdam wall body at the center composed of the panel and the anti-erosion side plates; the two anti-erosion side plates are fixed by the insertion blocks and the insertion holes, and positioning plates are symmetrically arranged inside the anti-erosion side plates and fixed to the panel by the connecting rods; both ends of the docking rod are welded with docking plates and placed in the docking grooves of the positioning plates;

[0025] Several anti-erosion spiral devices composed of elastic components, support rods, rod bodies and blades are arranged on the outer side of the anti-erosion side plates. The top of the rod body is provided with blades, the bottom is fixed to the side plates, and elastic components are arranged through the support rods to form a buffer;

[0026] Bottom plates are symmetrically installed at the bottom of the anti-erosion side plates, and angle bolts are arranged on the installed bottom plates;

[0027] The slide rail is fixed to the erosion - proof side plate through a connecting plate and installed in the limit groove provided on the panel. The corresponding sliding blocks outside the cofferdam wall body are placed in the slide rail for quick positioning and fixing; lifting rings are welded on the panel.

[0028] Further, in step four, the air inlet pipe during sand - blowing and sinking is placed in the arc - shaped limit grooves reserved on the left and right frames and is connected to the threaded rod and the sand outlet pipe in sequence; the left and right frames are fixed by bolts through fixing plates; water filling pipes are arranged inside the two frames and are connected to the spray heads through telescopic rods, and support rods are arranged and connected to the cleaning brushes through telescopic rods.

[0029] A screw rod with a propeller head is placed inside the threaded rod and can rotate and move up and down along the threaded rod through the rotation of the propeller head and the up - and - down movement of the screw rod; when the propeller head is wrapped and polluted by sediment, the spray head and the cleaning brush are extended to wash and clean the propeller head.

[0030] Further, in step six, the specific steps for correcting the deviation by adjusting the weight distribution on both sides of the cofferdam are as follows:

[0031] A hanging water tank ballast system is installed on the steel trestle, which consists of a load - bearing plate, side plates and connecting plates to form a frame structure; a ladder is installed on the side plates, and an operating platform with a safety guardrail fixed by a telescopic rod is arranged on the load - bearing plate.

[0032] Support columns and diagonal rods are welded and fixed on both sides of the main water inlet pipe, which are respectively connected to the pump and the water inlet tank; the horizontal water inlet pipe is connected to the main water inlet pipe, and a number of water inlet branch pipes are evenly arranged at its bottom and connected to the hanging water tanks.

[0033] The outlet pipe is installed at the bottom of the hanging water tank and is provided with outlet branch pipes connected to the outlet tank; during construction, the pump is used to inject water into the hanging water tanks at the higher positions of the cofferdam.

[0034] Further, in step six, if too much water is injected into the hanging water tank, the valve on the outlet pipe is opened to make the water flow into the outlet tank, achieving the effect of correcting the cofferdam deviation.

[0035] The combined sinking deep - water double - wall steel cofferdam is constructed by the above - mentioned construction method of the combined sinking deep - water double - wall steel cofferdam.

[0036] Compared with the prior art, the present invention has the following characteristics and beneficial effects:

[0037] 1. The present invention adopts the technology of using a steel casing to assist the overall lowering of the steel cofferdam. By means of the U - shaped limit device set on the steel casing, the cofferdam wall body is quickly assembled, and with the jack lowering system and the retractable bracket support, the cofferdam is quickly sunk, improving the overall lowering speed of the steel cofferdam.

[0038] 2. The present invention adopts the technology of temporary steel cofferdam anti-erosion on the sand-blowing riverbed. Angle bolts are arranged at the bottom of the anti-erosion side plates to improve the landing speed of the cofferdam in the sand-blowing riverbed. The slide rails and sliders are used to quickly position and fix the cofferdam, and it is lifted in combination with the jack lowering system and pulled up by the hanging rods. The temporary anti-erosion steel cofferdam is quickly removed and recycled.

[0039] 3. The present invention adopts the technology of high-side water injection and eccentric load pressing to correct deviation. An adjustable safety operation platform is set up, and a hanging water tank pressing system is installed. Water is injected into the hanging water tank at the higher part of the cofferdam by using a pump. When there is too much water in the tank, the valve is adjusted to make the water flow into the outlet tank to achieve the effect of correcting the deviation of the cofferdam.

[0040] 4. The present invention adopts the technology of sand-blowing under the cofferdam to sink. Through the rotation of the propeller head and the up and down movement of the screw rod, the rapid rotation and stirring of the bottom sediment are realized, and the sinking speed of the sediment under the cofferdam is increased; when the propeller head is wrapped and polluted by sediment, the propeller head is washed by the nozzle and the cleaning brush to ensure the normal operation of the sand-blowing equipment. Description of the Drawings

[0041] Figure 1 It is a schematic structural diagram of the steel cofferdam assembly platform;

[0042] Figure 2 It is an elevation schematic diagram of the auxiliary overall lowering of the steel cofferdam by the steel casing;

[0043] Figure 3 It is an elevation cross-sectional view of the bracket support;

[0044] Figure 4 It is an elevation cross-sectional view after the bracket support shrinks;

[0045] Figure 5 It is a schematic structural diagram of the temporary steel cofferdam anti-erosion on the sand-blowing riverbed;

[0046] Figure 6 It is a schematic structural diagram of the temporary steel cofferdam anti-erosion on the sand-blowing riverbed before assembly;

[0047] Figure 7 It is a schematic structural diagram of the anti-erosion spiral device;

[0048] Figure 8 It is a schematic structural diagram of the sand-blowing under the cofferdam sinking equipment;

[0049] Figure 9 It is a schematic structural diagram of the sand-blowing under the cofferdam sinking equipment before assembly;

[0050] Figure 10 It is a schematic structural diagram of the high-side water injection and eccentric load pressing to correct deviation;

[0051] Figure 11 It is a plan view of the high-side water injection and eccentric load pressing to correct deviation.

[0052] In the figure: 1, vertical column; 2, telescopic diagonal brace; 3, rotating nut; 4, rotating shaft; 5, screw rod; 6, support plate; 7, cross brace; 8, U-shaped groove; 9, limit plate; 10, jack; 11, top plate; 12, bearing plate; 13, bracket support; 14, U-shaped limit device; 15, cofferdam wall body; 16, jack lowering system; 17, connecting block; 18, spring rod; 19, bottom plate; 20, anti-scouring side plate; 21, lifting ring; 22, limit groove; 23, slide rail; 24, suspension rod; 25, slider; 26, panel; 27, anti-scouring spiral device; 28, angle bolt; 29, docking plate; 30, docking rod; 31, docking groove; 32, positioning plate; 33, connecting rod; 34, jacking hole; 35, inserting block; 36, elastic component; 37, support rod; 38, rod body; 39, blade; 40, bearing plate; 41, telescopic rod; 42, water outlet branch pipe; 43, suspended water tank; 44, water outlet tank; 45, water inlet cross pipe; 46, support column; 47, water inlet main pipe; 48, water inlet branch pipe; 49, water outlet pipe; 50, diagonal rod; 51, safety guardrail; 52, water inlet tank; 53, pump; 54, steel trestle; 55, connecting plate; 56, operation platform; 57, side plate; 58, ladder; 59, suspended water tank weight system; 60, sprinkler head; 61, cleaning brush; 62, water filling pipe; 63, frame body; 64, air inlet pipe; 65, sand outlet pipe; 66, fixing plate; 67, screw rod; 68, propeller head; 69, threaded rod; 70, arc-shaped limit groove; 71, steel casing; 72, connecting plate. Detailed implementation manners

[0053] The present invention will be further described below in conjunction with embodiments, and traditional construction methods such as welding and installation will not be elaborated in detail. The descriptions of the following embodiments are only used to help understand the present invention. It should be noted that for those of ordinary skill in the art of this technology, without departing from the principle of the present invention, several improvements and modifications can still be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0054] Those skilled in the art should understand that in the disclosure of this application, the orientation or positional relationships indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings. It is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limiting this application.

[0055] Figure 1 It is a structural schematic diagram of a steel cofferdam assembly platform; Figure 2 It is an elevation schematic diagram of the overall lowering of the steel casing assisting the steel cofferdam; Figure 3It is an elevation sectional view of the bracket support; Figure 4 It is an elevation sectional view after the bracket support shrinks; Figure 5 It is a structural schematic diagram of the anti-scouring of the temporary steel bulkhead in the sand-blowing riverbed; Figure 6 It is a structural schematic diagram of the anti-scouring of the temporary steel bulkhead in the sand-blowing riverbed before assembly; Figure 7 It is a structural schematic diagram of the anti-scouring spiral device; Figure 8 It is a structural schematic diagram of the sand-blowing sinking equipment at the bottom of the cofferdam; Figure 9 It is a structural schematic diagram of the sand-blowing sinking equipment at the bottom of the cofferdam before assembly; Figure 10 It is a structural schematic diagram of the deviation correction by high-side water injection and eccentric load weighing; Figure 11 It is a plan view of the deviation correction by high-side water injection and eccentric load weighing.

[0056] Embodiment 1

[0057] Referring to the figures shown, the combined sinking deep-water double-wall steel cofferdam includes a column 1, a telescopic diagonal brace 2, a rotating nut 3, a rotating shaft 4, a screw rod 5, a support plate 6, a cross brace 7, a U-shaped groove 8, a limit plate 9, a jack 10, a top plate 11, a bearing plate 12, a bracket support 13, a U-shaped limit device 14, a cofferdam wall body 15, a jack lowering system 16, a connecting block 17, a spring rod 18, a bottom plate 19, an anti-scouring side plate 20, a lifting ring 21, a limit groove 22, a slide rail 23, a suspension rod 24, a slider 25, a panel 26, an anti-scouring spiral device 27, a corner bolt 28, a docking plate 29, a docking rod 30, a docking groove 31, a positioning plate 32, a tie rod 33, a jacking hole 34, a plug block 35, an elastic component 36, a support rod 37, a rod body 38, a blade 39, a load-bearing plate 40, a telescopic rod 41, a water outlet branch pipe 42, a suspended water tank 43, a water outlet tank 44, a water inlet cross pipe 45, a support column 46, a water inlet main pipe 47, a water inlet branch pipe 48, a water outlet pipe 49, an inclined rod 50, a safety guardrail 51, a water inlet tank 52, a pump 53, a steel trestle 54, a connecting plate 55, an operation platform 56, a side plate 57, a ladder 58, a suspended water tank weighing system 59, a nozzle 60, a cleaning brush 61, a water filling pipe 62, a frame body 63, an air inlet pipe 64, a sand outlet pipe 65, a fixing plate 66, a spiral rod 67, a propeller head 68, a threaded rod 69, an arc-shaped limit groove 70, a steel casing 71, a connecting plate 72; the combined sinking deep-water double-wall steel cofferdam adopts the technology of using a steel casing to assist the overall lowering of the steel cofferdam; the combined sinking deep-water double-wall steel cofferdam adopts the technology of preventing scouring of the temporary steel bulkhead in the sand-blowing riverbed; the combined sinking deep-water double-wall steel cofferdam adopts the technology of deviation correction by high-side water injection and eccentric load weighing; the combined sinking deep-water double-wall steel cofferdam adopts the technology of sand-blowing sinking at the bottom of the cofferdam.

[0058] In this embodiment, the technology of using a steel casing to assist the overall lowering of the steel cofferdam includes:

[0059] The bracket support 13 is installed on the steel casing 71, and a U-shaped limiting device 14 is arranged thereon to accurately position the cofferdam wall body 15; the bracket support 13 is composed of a cross brace 7, a column 1 and a telescopic diagonal brace 2 to form a frame structure, and a screw rod 5 provided with a support plate 6 is connected through a rotating nut 3 to enhance the stability of the structure; both ends of the telescopic diagonal brace 2 are provided with connecting blocks 17 which are respectively connected with the spring rods 18 in the cross brace 7 and the column 1; the U-shaped limiting device 14 is placed on the bearing plate 12, the top plate 11 is welded to the left end thereof, and a sliding groove is formed at the bottom to install the limiting plate 9; the cofferdam wall body 15 is placed between the limiting plate 9 and the right vertical plate of the U-shaped groove 8, and the relative distance between the limiting plate 9 and the right vertical plate of the U-shaped groove 8 is adjusted by a jack 10; after the assembly of each section of the cofferdam wall body 15 is completed, the steel cofferdam is lifted by the jack lowering system 16, the screw rods 5 at both ends are removed by rotating the rotating nut 3, so that the connecting block 17 moves along the direction in which the length of the spring rod 18 is shortened, and the included angle between the cross brace 7 and the column 1 is reduced by using the rotating shaft 4, achieving the purpose of rapid contraction of the bracket support 13 and avoiding the cumbersome steps of gradually removing the bracket support 13.

[0060] In this embodiment, the anti-erosion technology of the temporary steel cofferdam on the sand-blowing riverbed includes:

[0061] The cofferdam wall body 15 is placed at the center composed of the panel 26 and the anti-erosion side plates 20; the two anti-erosion side plates 20 are fixed by the insertion blocks 35 and the insertion holes 34, and positioning plates 32 are symmetrically arranged inside the anti-erosion side plates 20 and fixed to the panel 26 through the connecting rods 33; both ends of the docking rod 30 are welded with docking plates 29 and placed in the docking grooves 31 of the positioning plates 32; a number of anti-erosion spiral devices 27 composed of elastic components 36, support rods 37, rod bodies 38 and blades 39 are arranged on the outer side of the anti-erosion side plates 20, the blades 39 are arranged at the top of the rod bodies 38, the bottom is fixed to the side plates, and the elastic components 36 are arranged through the support rods 37 to form a buffer; the bottom of the anti-erosion side plates 20 is symmetrically installed with bottom plates 19, and angle bolts 28 are arranged thereon to improve the landing speed of the cofferdam in the sand-blowing riverbed; the slide rails 23 are fixed to the anti-erosion side plates 20 through the connecting plates 72 and installed in the limiting grooves 22 arranged on the panel 26, and the corresponding sliding blocks 25 are installed outside the cofferdam wall body 15 and placed in the slide rails 23 for rapid positioning and fixing; the lifting rings 21 are welded on the panel 26, after the sinking of the steel cofferdam is completed, it is lifted in cooperation with the jack lowering system 16 and pulled up by the suspension rods 24 to quickly remove and recycle the temporary anti-erosion steel cofferdam.

[0062] In this embodiment, the high-side water injection eccentric load counterweight correction technology includes:

[0063] A hanging water tank ballast system 59 is installed on the steel trestle 54, which consists of a load-bearing plate 40, side plates 57 and connecting plates 55 to form a frame structure; a ladder 58 is installed on the side plates 57, and an operating platform 56 with a safety guardrail 51 is fixedly provided on the load-bearing plate 40 through a telescopic rod 41; support columns 46 and diagonal rods 50 are welded on both sides of the water inlet main pipe 47 and fixed, and they are respectively connected to a pump 53 and a water inlet tank 52; a water inlet cross pipe 45 is connected to the water inlet main pipe 47, and a number of water inlet branch pipes 48 are evenly arranged at the bottom thereof and connected to a hanging water tank 43; a water outlet pipe 49 is installed at the bottom of the hanging water tank 43, and a water outlet branch pipe 42 is provided and connected to a water outlet tank 44; during construction, the pump 53 is used to inject water into the hanging water tank 43 at a higher position of the cofferdam. If too much water is injected into the hanging water tank 43, the valve on the water outlet pipe 49 is opened to allow the water to flow into the water outlet tank 44, achieving the effect of correcting the deviation of the cofferdam.

[0064] In this embodiment, the bottom sand blowing and sinking technology of the cofferdam includes:

[0065] An air inlet pipe 64 is placed in the arc-shaped limit grooves 70 reserved in the left and right frame bodies 63, and is successively connected to a threaded rod 69 and a sand outlet pipe 65; the left and right frame bodies 63 are fixed by bolts through a fixing plate 66; a water filling pipe 62 is arranged inside the two frame bodies 63, and is connected to a spray head 60 through a telescopic rod 41, and a support rod 37 is arranged and connected to a cleaning brush 61 through a telescopic rod 41; a screw rod 67 with a propeller head 68 is placed inside the threaded rod 69 and can rotate and move up and down along the threaded rod 69. Through the rotation of the propeller head 68 and the up and down movement of the screw rod 67, the bottom sediment is quickly rotated and stirred, improving the sinking speed of the cofferdam; when the propeller head 68 is wrapped and polluted by sediment, the spray head 60 and the cleaning brush 61 are extended to wash and clean the propeller head 68, ensuring the normal operation of the sand blowing equipment.

[0066] Embodiment 2

[0067] The construction method of the combined sinking deep-water double-wall steel cofferdam includes the following steps:

[0068] Step 1: Erection and assembly of the steel cofferdam assembly platform: The corbel supports 13 of the assembly platform are installed on the steel casing 71, and a U-shaped limiting device 14 is arranged thereon to accurately position the cofferdam wall body 15; the corbel supports 13 consist of a cross brace 7, a column 1 and a telescopic diagonal brace 2 to form a frame structure, and a screw rod 5 with a support plate 6 is connected through a rotating nut 3 to strengthen the stability of the structure; connecting blocks 17 are arranged at both ends of the telescopic diagonal brace 2 and are respectively connected to the spring rods 18 inside the cross brace 7 and the column 1; the U-shaped limiting device 14 is placed on the bearing plate 12, and its left end is welded with a top plate 11, and a sliding groove is formed at the bottom to install a limiting plate 9; the cofferdam wall body 15 is placed between the limiting plate 9 and the right vertical plate of the U-shaped groove 8, and the relative distance between the limiting plate 9 and the right vertical plate of the U-shaped groove 8 is adjusted through a jack 10 for cofferdam assembly.

[0069] Step 2. Installation of temporary anti-erosion steel sheeting for cofferdam: The cofferdam wall 15 is placed at the center composed of the panel 26 and the anti-erosion side plates 20; the two anti-erosion side plates 20 are fixed by the insertion blocks 35 and the insertion holes 34, and positioning plates 32 are symmetrically arranged inside the anti-erosion side plates 20 and fixed to the panel 26 through the connecting rods 33; both ends of the docking rod 30 are welded with docking plates 29 and placed in the docking grooves 31 of the positioning plates 32; several anti-erosion spiral devices 27 composed of elastic components 36, support rods 37, rod bodies 38 and blades 39 are arranged on the outer side of the anti-erosion side plates 20, the blade 39 is arranged at the top of the rod body 38, the bottom is fixed to the side plate, and the elastic component 36 is arranged through the support rod 37 to form a buffer; the bottom plates 19 are symmetrically installed at the bottom of the anti-erosion side plates 20, and angle bolts 28 are arranged thereon to improve the landing speed of the cofferdam in the sand-blowing riverbed; the slide rails 23 are fixed to the anti-erosion side plates 20 through the connecting plates 72 and installed in the limit grooves 22 arranged on the panel 26, and the corresponding sliding blocks 25 are installed outside the cofferdam wall 15 and placed in the slide rails 23 for quick positioning and fixing; the lifting rings 21 are welded on the panel 26.

[0070] Step 3. Sinking of the cofferdam in water: After the assembly of each section of the cofferdam wall 15 is completed, the steel cofferdam is lifted by the jack lowering system 16, the corbel supports 13 are retracted, and then the cofferdam is sunk. By uniformly injecting water into the cofferdam compartment and pouring the concrete for the cutting edge, the cofferdam is made to sink against the buoyancy.

[0071] Step 4. Sinking of the cofferdam by sand blowing: After the cutting edge of the cofferdam enters the riverbed and the concrete for the cutting edge is poured, the cofferdam is sunk by sand blowing; the air inlet pipe 64 is placed in the arc-shaped limit grooves 70 reserved in the left and right frames 63 and connected to the threaded rod 69 and the sand outlet pipe 65 in sequence; the left and right frames 63 are fixed by bolts through the fixing plates 66; the water filling pipes 62 are arranged inside the two frames 63 and connected to the nozzles 60 through the telescopic rods 41, and the support rods 37 are arranged to be connected to the cleaning brushes 61 through the telescopic rods 41; the screw rod 67 provided with the propeller head 68 is placed in the threaded rod 69 and can rotate and move up and down along the threaded rod 69. Through the rotation of the propeller head 68 and the up and down movement of the screw rod 67, the bottom sediment is quickly rotated and stirred to improve the sinking speed of the cofferdam; when the propeller head 68 is wrapped and polluted by sediment, the nozzle 60 and the cleaning brush 61 are extended to wash and clean the propeller head 68 to ensure the normal operation of the sand blowing equipment.

[0072] Step 5. Recycling of the temporary anti-erosion steel sheeting: After the sinking of the steel cofferdam is completed, it is lifted in cooperation with the jack lowering system 16 and pulled up by the hanging rods 24, and the temporary anti-erosion steel sheeting is quickly removed and recycled.

[0073] Step 6. High-side water injection and partial load ballasting for deviation correction: Install a hanging water tank ballasting system 59 on the steel trestle 54, which consists of a load-bearing plate 40, side plates 57 and connecting plates 55 to form a frame structure; install a ladder 58 on the side plates 57, and fix an operating platform 56 with a safety guardrail 51 on the load-bearing plate 40 through a telescopic rod 41; weld support columns 46 and diagonal rods 50 on both sides of the water inlet main pipe 47 and fix them, which are respectively connected to the pump 53 and the water inlet tank 52; the water inlet cross pipe 45 is connected to the water inlet main pipe 47, and a number of water inlet branch pipes 48 are evenly arranged at the bottom thereof and connected to the hanging water tank 43; the water outlet pipe 49 is installed at the bottom of the hanging water tank 43, and a water outlet branch pipe 42 is provided and connected to the water outlet tank 44; during construction, use the pump 53 to inject water into the hanging water tank 43 at a higher position of the cofferdam. If too much water is injected into the hanging water tank 43, open the valve on the water outlet pipe 49 to make the water flow into the water outlet tank 44 to achieve the effect of correcting the deviation of the cofferdam.

Claims

1. A construction method for combining and sinking deepwater double-walled steel cofferdams, characterized in that: The following steps are involved: Step 1: Set up and assemble the steel cofferdam assembly platform: Using the assembly platform to accurately locate the cofferdam wall (15) and assemble the cofferdam; Step 2: Installation of temporary anti-scour steel panels for cofferdam: Temporary anti-scour steel panels are installed on the cofferdam after assembly to reduce the impact of riverbed scour on the cofferdam during construction; Among them, the specific measures for installing temporary anti-scour steel panels are: The cofferdam wall (15) is placed at the center of the panel (26) and the anti-scour side plate (20); the anti-scour side plates (20) on both sides are fixed by means of plug blocks (35) and plug holes (34), and positioning plates (32) are symmetrically arranged inside the anti-scour side plates (20) and fixed to the panel (26) by connecting rods (33); docking plates (29) are welded to both ends of the docking rod (30) and placed in the docking grooves (31) of the positioning plates (32); A plurality of anti-scour spiral devices (27) composed of elastic components (36), support rods (37), a rod body (38) and blades (39) are arranged outside the anti-scour side plate (20); the blades (39) are arranged on the top of the rod body (38); the bottom is fixed to the side plate, and the elastic components (36) are arranged through the support rod (37) to form a buffer; A bottom plate (19) is symmetrically mounted on the bottom of the anti-scour side plate (20), and angle bolts (28) are arranged on the mounting bottom plate (19); The slide rail (23) is fixed to the anti-scour side plate (20) through the connecting plate (72), and is installed in a limiting groove (22) provided on the panel (26); the corresponding installation slide block (25) is placed in the slide rail (23) on the outside of the cofferdam wall (15) for rapid positioning and fixing; and a lifting ring (21) is welded on the panel (26); Step 3: The cofferdam sinks in water: After the cofferdam wall (15) of each segment is assembled, the steel cofferdam is lifted by the jack lowering system (16), the bracket support (13) of the assembly platform is retracted, and then the cofferdam is sunk. Water is evenly poured into the cofferdam compartment and blade foot concrete is poured, so that the cofferdam overcomes buoyancy and sinks. Step 4: Sand blowing and sinking of cofferdam: After the cofferdam blade foot enters the riverbed and the blade foot concrete is poured, sand blowing and sinking are carried out; Step 5: Temporary anti-scour steel fence recovery: After the steel cofferdam is lowered, it is lifted by the jack lowering system (16) and pulled upward by the suspension rod (24) to quickly dismantle and recover the temporary anti-scour steel cofferdam. Step 6: High side water injection, eccentric load and weight correction: Deviation correction is performed by adjusting the weight distribution on both sides of the cofferdam; The bracket support (13) of the assembly platform in step 1 is installed on the steel casing (71), and a U-shaped limit device (14) is provided on the steel casing (71) to accurately position the cofferdam wall (15); After the cofferdam wall (15) of each segment is assembled, the steel cofferdam is lifted by using a jack lowering system (16), and the screw rods (5) at both ends are removed by rotating the rotating nut (3), so that the connecting block (17) moves in the direction of shortening the length of the spring rod (18), and the angle between the cross brace (7) and the column (1) is reduced by using the rotating shaft (4), so as to achieve the purpose of rapid contraction of the corbel support (13); the corbel support (13) is composed of a cross brace (7), a column (1) and a telescopic diagonal brace (2) to form a frame structure, and the screw rods (5) provided with a support plate (6) are connected by rotating the nut (3) to enhance the stability of the structure; connecting blocks (17) are provided at both ends of the telescopic diagonal brace (2) to be respectively connected to the cross brace (7) and the spring rod (18) in the column (1).

2. The construction method of combined submerged deepwater double-walled steel cofferdam according to claim 1 is characterized in that: In step one, the U-shaped limiting device (14) is placed on the pressure plate (12), the left end of the U-shaped limiting device (14) is welded to the top plate (11), and the bottom is grooved to form a sliding groove for installing the limiting plate (9).

3. The construction method of combined submerged deepwater double-walled steel cofferdam according to claim 2 is characterized in that: In step 1, the cofferdam wall (15) is placed between the limiting plate (9) and the right side vertical plate of the U-shaped groove (8), and the relative distance between the limiting plate (9) and the right side vertical plate of the U-shaped groove (8) is adjusted by the jack (10) to assemble the cofferdam.

4. The construction method of combined submerged deepwater double-walled steel cofferdam according to claim 1 is characterized in that: In step 4, the air inlet pipe (64) during the sand blowing and sinking is placed in the arc-shaped limit groove (70) reserved in the left and right frames (63), and is connected to the threaded rod (69) and the sand outlet pipe (65) in sequence; the left and right frames (63) are fixed by bolts through the fixing plates (66); a water filling pipe (62) is arranged inside the frames (63) on both sides, and is connected to the nozzle (60) through the telescopic rod (41); a support rod (37) is arranged and connected to the cleaning brush (61) through the telescopic rod (41); A screw rod (67) provided with a screw propeller head (68) is placed in a threaded rod (69) and can rotate and move up and down along the threaded rod (69). When the screw propeller head (68) is contaminated by sand and mud, the screw propeller head (68) is flushed and cleaned by extending the nozzle (60) and the cleaning brush (61).

5. The construction method of the combined submerged deepwater double-walled steel cofferdam according to any one of claims 1 to 4, characterized in that: In step six, the specific steps for correcting the deviation by adjusting the weight distribution on both sides of the cofferdam are: A suspended water tank weight system (59) is installed on the steel trestle (54), and the frame structure is composed of a load-bearing plate (40), a side plate (57) and a connecting plate (55); a ladder (58) is installed on the side plate (57), and an operating platform (56) provided with a safety guardrail (51) is fixed on the load-bearing plate (40) through a telescopic rod (41); Support columns (46) and inclined rods (50) are welded on both sides of the water inlet main pipe (47) and fixed, and are respectively connected to the pump (53) and the water inlet tank (52); the water inlet transverse pipe (45) is connected to the water inlet main pipe (47), and a plurality of water inlet branch pipes (48) are evenly arranged at the bottom thereof and connected to the hanging water tank (43); The water outlet pipe (49) is installed at the bottom of the hanging water tank (43) and is provided with a water outlet branch pipe (42) connected to the water outlet tank (44). During construction, a pump (53) is used to inject water into the hanging water tank (43) at a higher position of the cofferdam.

6. The construction method of combined submerged deepwater double-walled steel cofferdam according to claim 5 is characterized in that: In step six, if the hanging water tank (43) is filled with too much water, the valve on the water outlet pipe (49) is opened to allow water to flow into the water outlet tank (44), thereby achieving the effect of correcting the cofferdam deviation.

7. Combined deep-water double-wall steel cofferdam, characterized in that: The invention is obtained by the construction method of the combined deep-water double-wall steel cofferdam as described in any one of claims 1 to 6.

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