A method for removing a double-wall steel cofferdam under an ultra-high working condition of well wall ballast concrete

Abstract

The application provides a double-wall steel cofferdam dismantling method under the ultra-high working condition of well wall ballast concrete, which comprises the following steps: removing the cofferdam inner support rod and inner wall panel above the cofferdam inner concrete in the double-wall steel cofferdam; reserving the concrete in the H range of the middle region of two adjacent bulkhead plates and the concrete in the T range of the two side regions of each bulkhead plate, thereby forming the reserved ballast concrete; using machinery to cooperate with manual chiseling to remove the remaining ballast concrete outside the reserved ballast concrete range, and simultaneously cutting off the cofferdam inner support rod and inner wall panel exposed in the process of chiseling the remaining ballast concrete; repeating step two until the remaining ballast concrete, cofferdam inner support rod and inner wall panel except the reserved ballast concrete are removed; opening the inner and outer communication device, injecting water into the cofferdam, so that the water level in the cofferdam is consistent with the water level outside the cofferdam; cutting off the temporary inclined support; removing the water-on part of the double-wall steel cofferdam, and removing the water-under part of the double-wall steel cofferdam. The dismantling method is convenient to operate, the process procedure is clear and easy to understand, the dismantling efficiency of the double-wall steel cofferdam can be greatly improved, and the safety risk can be reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of double-wall steel cofferdam dismantling construction, and particularly relates to a double-wall steel cofferdam dismantling method and post-installation method under the condition of well wall ballast concrete ultra-high working condition. BACKGROUND

[0002] The steel cofferdam is used as a working platform for the construction of the bridge tower and the pile foundation of the pier and a temporary water retaining structure during the construction of the pile cap. According to the requirements of the waterway department and the design, the steel cofferdam above the pile cap surface needs to be completely dismantled after the completion of the main bridge to meet the requirements of the navigation clearance and reduce the water blocking section of the river. After the steel cofferdam is lowered to the designed position, the concrete is generally filled in the gap between the well walls to play the role of fixing the steel support and transferring the load. The filling height of the concrete filled in the gap between the well walls directly affects the dismantling of the double-wall steel cofferdam after the completion of the mission.

[0003] The traditional dismantling method adopts the underwater cutting or underwater rope saw dismantling of the divers. The underwater cutting of the divers requires that there is no sedimentary river silt, construction leakage mixed mortar or filling concrete and other sundries in the cofferdam well wall within the cutting line range, otherwise the method cannot be implemented. For the cofferdam with the sedimentary river silt, construction leakage mixed mortar or filling concrete and other sundries in the well wall within the cutting line range, the underwater cutting of the rope saw needs to be used. The rope saw dismantling of the cofferdam has great construction difficulty, low efficiency, high cost and long period, and there is a lack of professional rope saw construction technical personnel in China. SUMMARY

[0004] The purpose of the present application is to provide a double-wall steel cofferdam dismantling method under the condition of well wall ballast concrete ultra-high working condition. The dismantling method is convenient to operate, the process procedure is clear and easy to understand, the dismantling efficiency of the double-wall steel cofferdam can be greatly improved, and the safety risk can be reduced.

[0005] In order to realize the above technical features, the purpose of the present application is realized as follows: a double-wall steel cofferdam dismantling method under the condition of well wall ballast concrete ultra-high working condition, which comprises the following steps:

[0006] Step one, removing the cofferdam inner support rod and inner wall panel above the concrete in the double-wall steel cofferdam;

[0007] Step two, reserving the concrete in the H range of the middle area of the adjacent two bulkhead plates and the concrete in the T range of the two side areas of each bulkhead plate to form the reserved ballast concrete; using the machinery to cooperate with the manual chiseling to remove the remaining ballast concrete outside the reserved ballast concrete range, and simultaneously cutting off the cofferdam inner support rod and inner wall panel exposed in the process of chiseling the remaining ballast concrete;

[0008] Step three, repeating step two until the remaining ballast concrete, cofferdam inner support rod and inner wall panel except the reserved ballast concrete are completely removed.

[0009] Step four, whether the stress of the cofferdam still meets the specification requirements after all the ballast concrete and the inner wall panel are removed, whether the temporary inclined support needs to be set according to the calculation result, if the requirements are met, the remaining part of the reserved ballast concrete is directly removed without setting the temporary inclined support, if the requirements are not met, the temporary inclined support is set in the remaining ballast concrete area removed in the first time, and then the remaining part of the reserved ballast concrete is removed;

[0010] Step five, the inner and outer communication device is opened, water is injected into the cofferdam, and the water level height in the cofferdam is consistent with the water level line outside the cofferdam;

[0011] Step six, the temporary inclined support is cut off;

[0012] Step seven, the water part of the double-wall steel cofferdam is removed;

[0013] Step eight, the underwater part of the double-wall steel cofferdam is removed.

[0014] The value of the intermediate area H of the two partition panels in the step two is 1m~1.5m.

[0015] The value of the two side areas T of each partition panel in the step two is 20cm~25 cm.

[0016] In the step four, one end of the temporary inclined support is fixed by back pulling the fine rolling threaded steel on the concrete pile cap, and the other end is welded and fixed with the steel cofferdam in the remaining ballast concrete area removed in the first time.

[0017] In the step six, if the temporary inclined support is not set in the step four, the temporary inclined support does not need to be cut off.

[0018] In the step seven, when the water part of the double-wall steel cofferdam is removed, the cutting line position needs to exceed the water level line to ensure that the cutting seam is exposed to the water surface after water is injected into the cofferdam.

[0019] In the step eight, when the underwater part of the double-wall steel cofferdam is removed, symmetrical cutting from the downstream to the upstream is adopted.

[0020] The present application has the following beneficial effects:

[0021] 1. The stripping of the inner wall panel of the double-wall steel cofferdam increases the operation space for removing the ballast concrete, improves the removal efficiency, and effectively reduces the construction cost.

[0022] 2. The present application adopts the inner partition panel reserved ballast concrete to avoid setting a large number of temporary supports in the cofferdam, thereby effectively reducing the difficulty of removal construction and saving the removal construction cost.

[0023] 3、The present application guarantees the overall structural strength of the cofferdam after the inner wall panel and the remaining ballast concrete in the demolition part are removed, eliminates the safety influence of water flow impact force on the overall rigidity and stability of the cofferdam, and effectively guarantees the safety of construction.

[0024] 4、The strength of the support to the inner wall panel in the subsequent inner wall panel removal process is guaranteed by the temporary inclined support, thereby guaranteeing the safety of the removal process. BRIEF DESCRIPTION OF DRAWINGS

[0025] The present application will be further described below in combination with the drawings and embodiments.

[0026] Fig. 1 The flow chart of the double-wall steel cofferdam removal of the present application.

[0027] Fig. 2 The steel cofferdam compartment axis development plan of the present application.

[0028] Fig. 3 The temporary inclined support schematic diagram of the present application.

[0029] In the figure, the double-wall steel cofferdam 1, the reserved ballast concrete 2, the remaining ballast concrete 3, the compartment plate 4, the temporary inclined support 5, the inner wall panel 6, and the concrete pile cap 7. DETAILED DESCRIPTION

[0030] The embodiments of the present application will be further described below in combination with the drawings.

[0031] Embodiment 1:

[0032] Please refer to Figs. 1-3 A double-wall steel cofferdam removal method under the condition of well wall ballast concrete ultra-high working condition, which comprises the following steps:

[0033] Step one, remove the cofferdam inner support rod and the inner wall panel 6 above the cofferdam 1 inner concrete of the double-wall steel cofferdam;

[0034] Step two, reserve the concrete in the range of 1m~1.5m in the middle area of the adjacent two compartment plates 4 and the concrete in the range of 20cm~25cm in the two side areas of each compartment plate 4, thereby forming the reserved ballast concrete 2 together; use machinery to cooperate with manual chiseling to remove the remaining ballast concrete 3 outside the reserved ballast concrete 2 range, and simultaneously cut off the cofferdam inner support rod and the inner wall panel 6 exposed in the process of chiseling the remaining ballast concrete;

[0035] Step three, repeat step two until the remaining ballast concrete 3, cofferdam inner support rod and inner wall panel 6 except the reserved ballast concrete 2 are removed;

[0036] Step four, whether the stress of the cofferdam still meets the specification requirements after all the ballast concrete and the inner wall panel 6 are removed, to determine whether temporary diagonal bracing 5 is needed according to the calculation results; if the requirements are met, the remaining part of the reserved ballast concrete 2 is removed directly without setting temporary diagonal bracing 5; if the requirements are not met, the temporary diagonal bracing 5 is set in the area of the remaining ballast concrete 3 removed in the first time before the remaining part of the reserved ballast concrete 2 is removed;

[0037] When the temporary diagonal bracing 5 is needed, one end of the temporary diagonal bracing 5 is fixed by being pulled back through the finished rolled threaded steel to the concrete pile cap 7, and the other end is welded and fixed to the steel cofferdam in the area of the remaining ballast concrete 3 removed in the first time.

[0038] Step five, open the inner and outer communication device, and fill water into the cofferdam to make the water level in the cofferdam consistent with the water level outside the cofferdam.

[0039] Step six, cut off the temporary diagonal bracing 5; if the temporary diagonal bracing 5 is not set in step four, the temporary diagonal bracing 5 does not need to be cut off.

[0040] Step seven, remove the water part of the double-wall steel cofferdam 1; the cutting line position needs to exceed the water level to ensure that the cut seam is exposed to the water surface after the cofferdam is filled with water.

[0041] Step eight, remove the underwater part of the double-wall steel cofferdam 1; symmetrically cut from the downstream to the upstream.

[0042] Example 2:

[0043] In the process of a certain bridge construction, the double-wall steel cofferdam 1 is removed in the process of the double-wall steel cofferdam 1 removal after the main bridge is completed. First, the wood boards, steel components and other sundries placed in the well wall cabin are removed. After the silted sand and loose mortar above the concrete in the cabin are washed and sucked by the suction dredger and high-pressure water gun, the cofferdam inner support rod and the inner wall panel 6 above the concrete in the double-wall steel cofferdam 1 are removed. The remaining concrete 3 in the range of 1m~1.5m in the middle area of the reserved two cabin boards 4 and the range of 20cm on both sides of the cabin board is removed by mechanical cooperation with manual chiseling. The cofferdam inner support rod and the inner wall panel 6 exposed in the process of chiseling the remaining concrete are cut off. The step is repeated until the remaining concrete, inner support and inner wall panel 6 except the reserved concrete 2 are completely removed. Before chiseling the reserved concrete 2, the stress of the remaining double-wall steel cofferdam 1 structure is calculated. The results show that the combined stress and shear stress of the remaining double-wall steel cofferdam 1 meet the specification requirements, and the structure is safe. Therefore, temporary diagonal bracing 5 is not needed, and the remaining part of the reserved concrete 2 is directly chiseled. After the inner and outer communication devices are opened, the water level in the cofferdam is consistent with the river surface outside the cofferdam, and then the double-wall steel cofferdam 1 is removed. When the double-wall steel cofferdam 1 is removed, the water should be cut off in sequence, and then the underwater part of the double-wall steel cofferdam 1 is removed. When the upper part of the double-wall steel cofferdam 1 is removed, attention should be paid to the position of the cutting line, which needs to exceed the water level line to ensure that the water in the double-wall steel cofferdam 1 is exposed after cutting. Finally, the underwater part of the double-wall steel cofferdam 1 is cut from the downstream to the upstream symmetrically. The above completes the removal of the double-wall steel cofferdam 1 with all the super-high pressure concrete.

Claims

1. A method for removing a double-wall steel cofferdam in an ultra-high working condition of a well wall weight concrete, characterized in that, It comprises the following steps: Step one, remove the inner wall panel (6) and the inner support bar of the double-wall steel cofferdam (1) above the concrete; Step two, reserve the concrete in the middle area H of the two adjacent bulkhead plates (4) and the concrete in the area T on both sides of each bulkhead plate (4), thereby forming the reserved ballast concrete (2); use machinery to cooperate with manual chiseling to remove the remaining ballast concrete (3) outside the reserved ballast concrete (2), and simultaneously cut off the inner wall panel (6) and the inner support bar exposed during the chiseling of the remaining ballast concrete; Step three, repeat step two until the remaining ballast concrete (3), the inner wall panel (6) and the inner support bar are removed except for the reserved ballast concrete (2); Step four, theoretically calculate whether the stress of the cofferdam still meets the specification requirements after chiseling all the ballast concrete and the inner wall panel (6), and determine whether temporary diagonal bracing (5) is needed according to the calculation results; if the requirements are met, the remaining reserved ballast concrete (2) can be directly chiseled without setting temporary diagonal bracing (5); if the requirements are not met, set temporary diagonal bracing (5) in the area of the remaining ballast concrete (3) chiseled in the first time and then chisel the remaining reserved ballast concrete (2); Step five, open the inner and outer communication device, and fill water into the cofferdam so that the water level in the cofferdam is consistent with the water level outside the cofferdam; Step six, cut off the temporary diagonal bracing (5); Step seven, remove the water part of the double-wall steel cofferdam (1); Step eight, remove the underwater part of the double-wall steel cofferdam (1).

2. The method according to claim 1, wherein the method is characterized in that: The value of the middle area H of the two bulkhead plates (4) in step two is 1m~1.5m.

3. The method according to claim 1, wherein the method is characterized in that: The value of the area T on both sides of each bulkhead plate (4) in step two is 20cm~25 cm.

4. The method according to claim 1, wherein the method is characterized in that: In step four, one end of the temporary diagonal bracing (5) is fixed by reverse pulling the fine rolled threaded steel to the concrete pile cap (7), and the other end is welded to the steel cofferdam in the area of the remaining ballast concrete (3) chiseled in the first time.

5. The method of claim 1, wherein the method further comprises: In step six, if no temporary diagonal bracing (5) is set in step four, the temporary diagonal bracing (5) does not need to be cut off.

6. The method of claim 1, wherein the method further comprises: In step seven, when removing the water part of the double-wall steel cofferdam (1), the cutting line position needs to exceed the water level line to ensure that the cutting seam is exposed to water after the cofferdam is filled with water.

7. The method of claim 1, wherein the method further comprises: In step eight, when removing the underwater part of the double-wall steel cofferdam (1), symmetrically cut from downstream to upstream.

Images