Combined sinking deepwater double-wall steel cofferdam and construction method thereof

Abstract

The invention relates to a combined sinking deepwater double-wall steel cofferdam and a construction method thereof. The technology that a steel casing assists in overall lowering of the steel cofferdam is adopted. A sand blowing riverbed temporary steel coaming anti-scouring technology is adopted; a high-side water injection unbalance loading weight correction technology is adopted; and a cofferdam bottom sand blowing sinking technology is adopted. The construction method comprises the following main construction steps: (1) erecting and assembling a steel cofferdam assembling platform; the deepwater double-wall steel cofferdam has the advantages that the overall lowering speed of the deepwater double-wall steel cofferdam is increased, it is guaranteed that the temporary anti-scouring steel coaming is rapidly dismantled and recycled, and the deviation correction effect of the cofferdam is achieved.

Description

Technical Field

[0001] The invention relates to a deepwater double-wall steel cofferdam construction, in particular to a combined sinking deepwater double-wall steel cofferdam and a construction method thereof. Background Art

[0002] At present, my country's highway construction continues to advance, and the construction of deep-water bridge projects such as crossing rivers, lakes, etc. is increasing. In practice, double-walled steel cofferdams are often used for bridge foundation construction in deep-water areas. Due to the changeable water level and geological conditions in deep-water areas such as rivers, lakes, etc., if the construction method is unreasonable, the construction process is not scientifically set, and the construction supervision is weak, the sinking position of the bridge foundation may deviate, which will affect the construction safety and quality. Moreover, during the construction of the steel cofferdam, it was found that, especially for the lowering of the cofferdam on the sand-blowing riverbed, due to the weak anti-scouring ability of conventional steel cofferdams, it is easy to cause large deviations in the cofferdam bed. Therefore, how to innovate the design and improvement of the steel cofferdam construction technology is a key factor in the construction of large deep-water double-walled steel cofferdams.

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

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

[0005] In order to achieve the above technical objectives, the present invention adopts the following technical solutions: The construction method of the combined deep-water double-wall steel cofferdam comprises the following steps: Step 1: Set up and assemble the steel cofferdam assembly platform: Use the assembly platform to accurately locate the cofferdam wall 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; Step 3: The cofferdam sinks in water: After the cofferdam walls of each segment are assembled, the steel cofferdam is lifted by the jack lowering system, the bracket support of the assembly platform is retracted, and then the cofferdam is sunk. Water is evenly poured into the cofferdam compartments and the blade foot concrete is poured to make the cofferdam overcome the buoyancy and sink. 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 sunk, it is lifted by the jack lowering system and pulled up by the boom to quickly dismantle and recycle the temporary anti-scour steel cofferdam. Step 6: High side water injection, eccentric load and weight correction: Deviation correction is done by adjusting the weight distribution on both sides of the cofferdam.

[0006] Furthermore, in step 1, the bracket support of the assembly platform is installed on the steel casing, and a U-shaped limit device is provided on the steel casing to accurately position the cofferdam wall; After the assembly of the cofferdam walls of each segment is completed, the steel cofferdam is lifted using the jack lowering system. The screws at both ends are removed by turning the rotating nuts, so that the connecting block moves in the direction of shortening the length of the spring rod, and the angle between the cross brace and the column is reduced by the rotating shaft, so as to achieve the purpose of rapid contraction of the corbel support.

[0007] Furthermore, in step one, the corbel support is composed of a frame structure consisting of a transverse brace, a column and a telescopic diagonal brace, and the screw rod provided with the support plate is connected by a rotating nut to enhance the stability of the structure; connecting blocks are provided at both ends of the telescopic diagonal brace to be connected to the transverse brace and the spring rods in the column respectively; the U-shaped limit device is placed on the pressure plate, the left end of the U-shaped limit device is welded to the top plate, and the bottom is grooved to form a sliding groove to install the limit plate.

[0008] Furthermore, in step one, the cofferdam wall is placed between the limit plate and the right side vertical plate of the U-shaped groove, and the relative distance between the limit plate and the right side vertical plate of the U-shaped groove is adjusted by a jack to assemble the cofferdam.

[0009] Furthermore, in step 2, the specific measures for installing temporary anti-scour steel enclosures are: The cofferdam wall is placed in the center of the panel and the anti-scour side panel; the anti-scour side panels on both sides are fixed by means of plug blocks and sockets, and positioning plates are symmetrically arranged inside the anti-scour side panels and fixed to the panel by connecting rods; butt plates are welded at both ends of the butt rod and placed in the butt grooves of the positioning plates; Several anti-scour spiral devices consisting of elastic components, support rods, rod bodies and blades are arranged on the outside of the anti-scour side plates. Blades are arranged on the top of the rod body, and the bottom is fixed to the side plates. Elastic components are arranged through the support rods to form a buffer. The bottom plate is symmetrically installed at the bottom of the anti-scour side plate, and angle bolts are arranged on the installation bottom plate; The slide rail is fixed to the anti-scour side plate through a connecting plate and installed in a limit groove provided on the panel. The corresponding sliding block installed on the outside of the cofferdam wall is placed in the slide rail for quick positioning and fixing; a lifting ring is welded on the panel.

[0010] Furthermore, in step 4, the air inlet pipe when the sand is blown down is placed in the arc-shaped limit groove reserved in 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 the fixing plates; water filling pipes are arranged inside the frames on both sides, connected to the nozzles through the telescopic rods, and support rods are arranged to be connected to the cleaning brush through the telescopic rods; A spiral rod with a propeller head is placed in the threaded rod and can rotate and move up and down along the threaded rod. The propeller head rotates and the spiral rod moves up and down; when the propeller head is contaminated by mud and sand, the propeller head is flushed and cleaned by extending the nozzle and the cleaning brush.

[0011] Furthermore, in step six, the specific steps of correcting the deviation by adjusting the weight distribution on both sides of the cofferdam are: A hanging water tank weight-bearing system is installed on the steel trestle, which consists of a frame structure consisting of a load-bearing plate, side plates and connecting plates; a ladder is installed on the side plates, and an operating platform with a safety guardrail is fixed on the load-bearing plate through a telescopic rod; The water inlet main pipe is fixed with welding support columns and diagonal rods on both sides, which are connected to the pump and the water inlet tank respectively; the water inlet cross pipe is connected to the water inlet main pipe, and a number of water inlet branches are evenly arranged at its bottom to connect to the hanging water tank; The water outlet pipe is installed at the bottom of the hanging water tank, and a water outlet branch pipe is provided to connect with the water outlet tank; during construction, a pump is used to fill water into the hanging water tank at a higher point of the cofferdam.

[0012] Furthermore, in step six, if the hanging water tank is filled with too much water, the valve on the outlet pipe is opened to allow water to flow into the outlet tank, thereby achieving the effect of correcting the cofferdam deviation.

[0013] The combined deepwater double-walled steel cofferdam is constructed by the above-mentioned construction method of the combined deepwater double-walled steel cofferdam.

[0014] Compared with the prior art, the present invention has the following characteristics and beneficial effects: 1. The present invention adopts the technology of overall lowering of steel cofferdam assisted by steel casing, and uses the steel casing to set a U-shaped limit device to quickly assemble the cofferdam wall. The cofferdam is quickly sunk by using the jack lowering system and retractable bracket support, thereby improving the overall lowering speed of the steel cofferdam.

[0015] 2. The present invention adopts the anti-scour technology of temporary steel enclosures on the sand-blowing riverbed. Angle bolts are arranged at the bottom of the anti-scour side plates to increase the landing speed of the cofferdam in the sand-blowing riverbed. The cofferdam is quickly positioned and fixed by slide rails and sliders. The jack lowering system is used for lifting, and the temporary anti-scour steel enclosure is quickly dismantled and recovered in combination with the lifting of the boom.

[0016] 3. The present invention adopts high-side water injection and eccentric load weight correction technology, sets an adjustable safety operating platform, installs a hanging water tank weight correction system, and uses a pump to inject water into the hanging water tank at a higher point of the cofferdam. If too much water is injected into the tank, adjust the valve to allow water to flow into the outlet water tank, thereby achieving the effect of correcting the cofferdam deviation.

[0017] 4. The present invention adopts the cofferdam bottom sand blowing and sinking technology. Through the rotation of the spiral paddle head and the up and down movement of the spiral rod, the bottom sediment is quickly rotated and stirred, thereby increasing the sediment sinking speed under the cofferdam. When the spiral paddle head is wrapped and contaminated by sediment, the paddle head is flushed and cleaned through the nozzle and cleaning brush to ensure the normal operation of the sand blowing equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural diagram of the steel cofferdam assembly platform; Figure 2 It is a schematic elevation diagram of the overall lowering of the steel cofferdam assisted by the steel casing; Figure 3 It is the elevation section view of the corbel support; Figure 4 This is the elevation section view after the corbel support is contracted; Figure 5 It is a schematic diagram of the structure of temporary steel enclosure for sand-blowing riverbed to prevent scour; Figure 6 This is a schematic diagram of the structure of the temporary steel enclosure for sand-blowing riverbed before it is assembled to prevent scour; Figure 7 It is a schematic diagram of the structure of the anti-scour spiral device; Figure 8 It is a schematic diagram of the structure of the sand blowing and sinking equipment at the bottom of the cofferdam; Fig. 9 This is a schematic diagram of the structure of the sand blowing and sinking equipment at the bottom of the cofferdam before assembly; Fig.10 It is a structural diagram of high side water injection eccentric load weight correction; Fig.11 It is a plan view of the high side water injection and eccentric load correction.

[0019] In the figure: 1, column; 2, telescopic diagonal brace; 3, rotating nut; 4, rotating shaft; 5, screw; 6, support plate; 7, cross brace; 8, U-shaped groove; 9, limit plate; 10, jack; 11, top plate; 12, pressure plate; 13, bracket support; 14, U-shaped limit device; 15, cofferdam wall; 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, lifting 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, socket; 35, plug block; 36, elastic component; 37, support Support rod; 38, rod body; 39, blades; 40, load-bearing plate; 41, telescopic rod; 42, water outlet branch pipe; 43, hanging 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, inclined rod; 51, safety guardrail; 52, water inlet tank; 53, pump; 54, steel trestle; 55, connecting plate; 56, operating platform; 57, side plate; 58, ladder; 59, hanging water tank weight system; 60, nozzle; 61, cleaning brush; 62, water filling pipe; 63, frame; 64, air inlet pipe; 65, sand outlet pipe; 66, fixing plate; 67, spiral rod; 68, propeller head; 69, threaded rod; 70, arc limit groove; 71, steel casing; 72, connecting plate. DETAILED DESCRIPTION

[0020] The present invention is further described below in conjunction with embodiments, wherein conventional construction methods such as welding and installation are not described in detail. The description of the following embodiments is only used to help understand the present invention. It should be noted that, for those of ordinary skill in the art, several improvements and modifications may be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0021] Those skilled in the art should understand that, in the disclosure of the present application, the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, which are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply 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 understood as limiting the present application.

[0022] Figure 1 It is a structural diagram of the steel cofferdam assembly platform; Figure 2 It is a schematic elevation diagram of the overall lowering of the steel cofferdam assisted by the steel casing; Figure 3 It is the elevation section view of the corbel support; Figure 4 This is the elevation section view after the corbel support is contracted; Figure 5 It is a schematic diagram of the structure of temporary steel enclosure for sand-blowing riverbed to prevent scour; Figure 6 This is a schematic diagram of the structure of the temporary steel enclosure for sand-blowing riverbed before it is assembled to prevent scour; Figure 7 It is a schematic diagram of the structure of the anti-scour spiral device; Figure 8 It is a schematic diagram of the structure of the sand blowing and sinking equipment at the bottom of the cofferdam; Fig. 9 This is a schematic diagram of the structure of the sand blowing and sinking equipment at the bottom of the cofferdam before assembly; Fig.10 It is a structural diagram of high side water injection eccentric load weight correction; Fig.11 It is a plan view of the high side water injection and eccentric load correction.

[0023] Example 1 Referring to the figures, the combined sinking deepwater double-wall steel cofferdam includes a column 1, a telescopic diagonal brace 2, a rotating nut 3, a rotating shaft 4, a screw 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 pressure plate 12, a bracket support 13, a U-shaped limit device 14, a cofferdam wall 15, a jack lowering system 16, a connecting block 17, a spring rod 18, a bottom plate 19, an anti-scouring side plate 20, and a lifting ring 2 1, limit groove 22, slide rail 23, suspension rod 24, slider 25, panel 26, anti-scouring spiral device 27, angle bolt 28, docking plate 29, docking rod 30, docking groove 31, positioning plate 32, connecting rod 33, jack 34, plug block 35, elastic component 36, support rod 37, rod body 38, blade 39, load-bearing plate 40, telescopic rod 41, water outlet branch pipe 42, hanging water tank 43, water outlet tank 44, water inlet transverse pipe 45, support column 46, water inlet main pipe 47, water inlet branch pipe 48, water outlet pipe 49, inclined rod 50, safety guardrail 51, water inlet tank 52, pump 53, steel trestle 54, connecting plate 55, operating platform 56, side plate 57, ladder 58, hanging water tank weight system 59, nozzle 60, cleaning brush 61, water filling pipe 62, frame 63, air inlet pipe 64, sand outlet pipe 65, fixing plate 66, screw rod 67, propeller head 68, threaded rod 69, arc-shaped limit groove 70, steel casing 71, connecting plate 72; the combined deep-water double-wall steel cofferdam adopts the steel casing-assisted steel cofferdam overall lowering technology; the combined deep-water double-wall steel cofferdam adopts the sand-blowing riverbed temporary steel enclosure anti-scouring technology; the combined deep-water double-wall steel cofferdam adopts the high-side water injection eccentric load weight correction technology; the combined deep-water double-wall steel cofferdam adopts the cofferdam bottom sand blowing sinking technology.

[0024] In this embodiment, the steel casing assisted steel cofferdam overall lowering technology includes: The corbel support 13 is installed on the steel casing 71, and a U-shaped limit device 14 is arranged on it to accurately position the cofferdam wall 15; 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 is connected to a screw 5 with a support plate 6 by a rotating nut 3 to enhance 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 cross brace 7 and the spring rod 18 in the column 1; the U-shaped limit device 14 is placed on the pressure plate 12, and the top plate 11 is welded at its left end, and a slot is opened at the bottom to form a sliding slot for installing the limit plate 9; the cofferdam The weir wall body 15 is placed between the limit plate 9 and the right side vertical plate of the U-shaped groove 8, and the relative distance between the limit plate 9 and the right side vertical plate of the U-shaped groove 8 is adjusted by the jack 10; after the assembly of each segment cofferdam wall body 15 is completed, the steel cofferdam is lifted by the jack lowering system 16, and the screws 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 the rotating shaft 4, so as to achieve the purpose of rapid contraction of the corbel support 13, avoiding the tedious steps of gradually removing the corbel support 13.

[0025] In this embodiment, the scouring prevention technology of temporary steel enclosure for sand-blowing riverbed includes: The cofferdam wall 15 is placed in the center composed 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 sockets 34, and positioning plates 32 are symmetrically arranged inside the anti-scour side plates 20, and are fixed to the panel 26 by connecting rods 33; docking plates 29 are welded at both ends of the docking rod 30 and placed in the docking groove 31 of the positioning plate 32; a number of anti-scour spiral devices 27 composed of elastic components 36, support rods 37, rod bodies 38 and blades 39 are arranged on the outside of the anti-scour side plates 20, blades 39 are arranged on the top of the rod body 38, and the bottom is fixed to the side plate, and is connected to the side plate by connecting rods 33. An elastic component 36 is arranged through the support rod 37 to form a buffer; a bottom plate 19 is symmetrically installed at the bottom of the anti-scour side plate 20, and an angle bolt 28 is arranged on it to improve the landing speed of the cofferdam in the sand-blowing riverbed; the slide rail 23 is fixed to the anti-scour side plate 20 through the connecting plate 72, and it is installed in the limit groove 22 set on the panel 26, and the slider 25 is correspondingly installed on the outside of the cofferdam wall 15 and placed in the slide rail 23 for rapid positioning and fixing; a lifting ring 21 is welded on the panel 26. After the steel cofferdam is sunk, it is lifted in conjunction with the jack lowering system 16, and combined with the upward pull of the suspension rod 24, the temporary anti-scour steel cofferdam is quickly removed and recovered.

[0026] In this embodiment, the high side water injection eccentric load weight correction technology includes: A hanging 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 of 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, which 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 number of water inlet branches 48 are evenly arranged at its bottom 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 to connect the 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 water to flow into the water outlet tank 44, thereby achieving the effect of correcting the cofferdam deviation.

[0027] In this embodiment, the cofferdam bottom sand blowing and sinking technology includes: The air inlet pipe 64 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 turn; the left and right side frames 63 are fixed by bolts through the fixing plate 66; a water filling pipe 62 is arranged inside the two side frames 63, which is connected to the nozzle 60 through the telescopic rod 41, and a support rod 37 is arranged to be connected to the cleaning brush 61 through the telescopic rod 41; the spiral rod 67 with a 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 propeller head 67, the bottom mud and sand can be quickly rotated and stirred, thereby increasing the sinking speed of the cofferdam; when the propeller head 68 is wrapped and contaminated by mud and sand, the propeller head 68 is flushed and cleaned by extending the nozzle 60 and the cleaning brush 61 to ensure the normal operation of the sand blowing equipment.

[0028] Example 2 The construction method of the combined deep-water double-wall steel cofferdam comprises the following steps: Step 1, erection and assembly of steel cofferdam assembly platform: the corbel support 13 of the assembly platform is installed on the steel casing 71, and a U-shaped limit device 14 is arranged on it to accurately position the cofferdam wall 15; 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 is connected to a screw 5 with a support plate 6 by a rotating nut 3 to enhance 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 cross brace 7 and the spring rod 18 in the column 1; the U-shaped limit device 14 is placed on the pressure plate 12, the left end of which is welded with the top plate 11, and the bottom is grooved to form a sliding groove to install the limit plate 9; the cofferdam wall 15 is placed between the limit plate 9 and the right side plate of the U-shaped groove 8, and the relative distance between the limit plate 9 and the right side plate of the U-shaped groove 8 is adjusted by the jack 10 to assemble the cofferdam.

[0029] Step 2: Installation of temporary anti-scour steel panels for the cofferdam: The cofferdam wall 15 is placed in the center of the panel 26 and the anti-scour side panels 20; the anti-scour side panels 20 on both sides are fixed by means of plug blocks 35 and sockets 34, and positioning plates 32 are symmetrically arranged inside the anti-scour side panels 20, and fixed to the panel 26 by connecting rods 33; docking plates 29 are welded at both ends of the docking rods 30 and placed in the docking grooves 31 of the positioning plates 32; a number of anti-scour steel panels 20 consisting of elastic components 36, support rods 37, rod bodies 38 and blades 39 are arranged on the outside of the anti-scour side panels 20. A scouring spiral device 27 is provided with a blade 39 on the top of the rod body 38, which is fixed to the side plate at the bottom, and an elastic component 36 is provided through the support rod 37 to form a buffer; a bottom plate 19 is symmetrically installed at the bottom of the anti-scouring side plate 20, and an angle bolt 28 is arranged on it to increase the landing speed of the cofferdam in the sand-blowing riverbed; the slide rail 23 is fixed to the anti-scouring side plate 20 through a connecting plate 72, and is installed in a limiting groove 22 provided on the panel 26, and a slider 25 is correspondingly installed on the outside of the cofferdam wall body 15 and placed in the slide rail 23 for rapid positioning and fixing; a lifting ring 21 is welded on the panel 26.

[0030] Step 3: sinking the cofferdam 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 is retracted, and then the cofferdam is sunk. Water is evenly injected into the cofferdam compartment and blade foot concrete is poured to make the cofferdam overcome buoyancy and sink.

[0031] Step 4, sand blowing and sinking of the cofferdam: after the blade foot of the cofferdam enters the riverbed and the blade foot concrete is poured, sand blowing and sinking are carried out; the air inlet pipe 64 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 turn; the left and right side frames 63 are fixed by bolts through the fixing plates 66; a water filling pipe 62 is arranged inside the two side frames 63, which is connected to the nozzle 60 through the telescopic rod 41, and a support rod 37 is arranged to be connected to the cleaning brush 61 through the telescopic rod 41; the spiral rod 67 with a propeller head 68 is placed in the threaded rod 69, which can rotate and move up and down along the threaded rod 69, and the rotation of the propeller head 68 and the up and down movement of the propeller head 67 can realize the rapid rotation and stirring of the bottom sediment, thereby increasing the sinking speed of the cofferdam; when the propeller head 68 is wrapped and contaminated by sediment, the propeller head 68 is flushed and cleaned by extending the nozzle 60 and the cleaning brush 61 to ensure the normal operation of the sand blowing equipment.

[0032] Step 5: Recovering the temporary anti-scour steel coaming: After the steel coaming is lowered, the temporary anti-scour steel coaming is quickly removed and recovered by coordinating with the jack lowering system 16 and pulling up the suspension rod 24.

[0033] Step 6: High side water injection and weight correction: A hanging water tank weight correction system 59 is installed on the steel trestle 54, which is composed of a load-bearing plate 40, a side plate 57 and a connecting plate 55 to form a frame structure; a ladder 58 is installed on the side plate 57, and an operating platform 56 of 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, which are connected to the pump 53 and the water inlet tank 52 respectively; the water inlet cross pipe 45 is connected to the water inlet main pipe 47, and a number of water inlet branches 48 are evenly arranged at the bottom thereof and connected to the 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 to connect 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. If too much water is injected into the hanging water tank 43, 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.

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; 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.

2. The construction method of combined submerged deepwater double-walled steel cofferdam according to claim 1 is characterized in that: In step 1, the bracket support (13) of the assembly platform 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 assembly of the cofferdam wall (15) of each segment is completed, the steel cofferdam is lifted by using the jack lowering system (16), and the screw rods (5) at both ends are removed by rotating the rotating nuts (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).

3. The construction method of combined submerged deepwater double-walled steel cofferdam according to claim 2 is characterized in that: In step 1, 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 is connected to a screw rod (5) provided with a support plate (6) by a rotating 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); a U-shaped limit device (14) is placed on the pressure plate (12), the left end of which is welded to the top plate (11), and the bottom is grooved to form a sliding groove to install the limit plate (9).

4. The construction method of combined submerged deepwater double-walled steel cofferdam according to claim 3 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.

5. The construction method of combined submerged deepwater double-walled steel cofferdam according to claim 1 is characterized in that: In step 2, 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 a connecting plate (72) and is installed in a limiting groove (22) provided on the panel (26). The corresponding sliding block (25) is installed outside the cofferdam wall (15) and is placed in the slide rail (23) for rapid positioning and fixing. A lifting ring (21) is welded on the panel (26).

6. 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).

7. The construction method of the combined submerged deepwater double-walled steel cofferdam according to any one of claims 1 to 6, 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.

8. The construction method of combined submerged deepwater double-walled steel cofferdam according to claim 7 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.

9. 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 8.

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