CN113216228A - Construction process of combined pile cofferdam - Google Patents

Construction process of combined pile cofferdam Download PDF

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Publication number
CN113216228A
CN113216228A CN202110440396.1A CN202110440396A CN113216228A CN 113216228 A CN113216228 A CN 113216228A CN 202110440396 A CN202110440396 A CN 202110440396A CN 113216228 A CN113216228 A CN 113216228A
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Prior art keywords
cofferdam
water
pile
concrete
pumping
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Inventor
黄成�
李帅
徐伟
苏爱俊
王文博
贺新尊
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No2 Engineering Co Ltd Of Cccc Third Harbor Engineering Co ltd
CCCC Third Harbor Engineering Co Ltd
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No2 Engineering Co Ltd Of Cccc Third Harbor Engineering Co ltd
CCCC Third Harbor Engineering Co Ltd
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Publication of CN113216228A publication Critical patent/CN113216228A/en
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    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D19/00Keeping dry foundation sites or other areas in the ground
    • E02D19/02Restraining of open water
    • E02D19/04Restraining of open water by coffer-dams, e.g. made of sheet piles
    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D15/00Handling building or like materials for hydraulic engineering or foundations
    • E02D15/02Handling of bulk concrete specially for foundation or hydraulic engineering purposes
    • E02D15/06Placing concrete under water
    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D5/00Bulkheads, piles, or other structural elements specially adapted to foundation engineering
    • E02D5/02Sheet piles or sheet pile bulkheads
    • E02D5/03Prefabricated parts, e.g. composite sheet piles
    • E02D5/04Prefabricated parts, e.g. composite sheet piles made of steel
    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D5/00Bulkheads, piles, or other structural elements specially adapted to foundation engineering
    • E02D5/22Piles
    • E02D5/24Prefabricated piles
    • E02D5/28Prefabricated piles made of steel or other metals
    • E02D5/285Prefabricated piles made of steel or other metals tubular, e.g. prefabricated from sheet pile elements

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  • Engineering & Computer Science (AREA)
  • Structural Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Mining & Mineral Resources (AREA)
  • Paleontology (AREA)
  • Civil Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Composite Materials (AREA)
  • Placing Or Removing Of Piles Or Sheet Piles, Or Accessories Thereof (AREA)

Abstract

The invention provides a construction process of a combined pile cofferdam, which comprises the following steps: installing a positioning pile and a guide frame, and inserting and driving a lock catch pipe pile and a steel plate pile; the lock catch pipe piles and the steel sheet piles form a cofferdam, and the bottom of the cofferdam is subjected to underwater sand suction and desilting; pouring concrete on the bottom of the cofferdam underwater by adopting a vertical conduit method; pumping water in the cofferdam for multiple times, and mounting a surrounding purlin and a support after each water pumping until the water in the cofferdam is pumped to a designed elevation; and (5) pumping water and dredging, and then carrying out leveling layer construction. According to the invention, the concrete is poured after the sand is sucked and the silt is removed from the bottom of the cofferdam, the surrounding purlin and the support are pumped and installed in turn, and finally the leveling layer is constructed, so that the stability is improved, and the waterproof effect is better due to the use of the combined pile.

Description

Construction process of combined pile cofferdam
Technical Field
The invention relates to the field of cofferdam construction, in particular to a construction process of a combined pile cofferdam.
Background
The cofferdam is a temporary enclosure structure constructed for constructing permanent water conservancy facilities in the water conservancy project construction. The cofferdam has the functions of preventing water and soil from entering the building position of the building so as to drain water in the cofferdam, excavate a foundation pit and build the building.
The cofferdam is mainly used in hydraulic buildings in general, and the cofferdam is dismantled after being used up except for being used as a part of a formal building. The cofferdam height is higher than the highest water level that may occur during construction. The cofferdam can be used for preventing water and enclosing water and can also be used for supporting the pit wall of the foundation pit.
In order to improve the stability and the waterproof performance of the cofferdam, a combined pile cofferdam construction process is urgently needed to be researched.
Disclosure of Invention
The embodiment of the invention provides a construction process of a combined pile cofferdam, which comprises the steps of firstly sucking sand and dredging at the bottom of the cofferdam, then pouring concrete, then pumping water in times, installing purlins and supports, and finally constructing a leveling layer, so that the stability is improved, and the waterproof effect is better due to the use of combined piles.
The technical scheme for realizing the purpose of the invention is as follows:
a construction process of a combined pile cofferdam comprises the following steps:
installing a positioning pile and a guide frame, and inserting and driving a lock catch pipe pile and a steel plate pile;
the lock catch pipe piles and the steel sheet piles form a cofferdam, and the bottom of the cofferdam is subjected to underwater sand suction and desilting;
pouring concrete on the bottom of the cofferdam underwater by adopting a vertical conduit method;
pumping water in the cofferdam for multiple times, and mounting a surrounding purlin and a support after each water pumping until the water in the cofferdam is pumped to a designed elevation;
and (5) pumping water and dredging, and then carrying out leveling layer construction.
In this embodiment, installation spud and leading truck includes:
installing and roughly positioning the guide frame at a specified position;
a dust guard is arranged at the bottom of the guide frame and then placed on the mud surface;
positioning piles are adopted as auxiliary pile legs of the guide frame, the positioning piles penetrate through the guide frame and are sunk to be 30-80 m below the mud surface,
and leveling and fixing the guide frame on the positioning pile.
In this embodiment, insert and beat hasp tubular pile and steel sheet pile, include:
blanking and processing the lock catch tubular pile;
hoisting and stacking the fore shaft steel pipe piles;
and constructing the fore shaft steel pipe pile.
In this embodiment, hasp tubular pile and steel sheet pile enclose into the cofferdam, inhales husky desilting under water to the bottom in cofferdam, include:
floating mud and gravels in the cofferdam need to be removed before the bottom sealing concrete is poured, so that a harmful interlayer does not exist between the substrate and the bottom sealing concrete;
sand is sucked in the cofferdam through surface treatment of the steel casing, the steel pipe pile and the steel sheet pile, only the large-range silt in the cofferdam is removed, and the silt adhered to the surface of the cofferdam is thoroughly removed by adopting high-pressure water jet before bottom sealing.
In this embodiment, the pouring of concrete to the bottom of the cofferdam by the vertical conduit method under water includes:
a plurality of catheters are adopted for perfusion, wherein two catheters are reserved;
the top of the conduit is connected with a funnel, and the funnel is connected with a concrete storage bin with a certain capacity;
the catheter is assembled in a trial mode before use and subjected to a water tightness experiment.
In this embodiment, draw water in the cofferdam for a plurality of times, all install one and enclose purlin and support after drawing water at every turn, draw water to design elevation in the cofferdam until, include:
pumping water in the steel cofferdam after the bottom sealing concrete reaches the design strength;
pumping water in the cofferdam to a first elevation, and installing a first purlin and a support;
pumping water in the cofferdam to a second elevation, and installing a second purlin and a support;
pumping water in the cofferdam to a third elevation, and installing a third purlin and a support;
pumping water in the cofferdam to the designed elevation.
In this embodiment, the water pumping work includes:
and arranging the number of the water pumps according to the size of the cofferdam and the actual water depth condition in the cofferdam.
In this embodiment, the pumping of water in the cofferdam to the designed elevation includes:
after the upper layer is ensured to be safe, the water is continuously pumped to enter the lower layer for construction;
pumping water to the top surface of the bottom sealing concrete.
In this embodiment, draw water and carry out levelling layer construction after the desilting, include:
removing sludge and sundries on the bottom sealing concrete;
and (5) constructing a leveling layer.
In this embodiment, the cofferdam is provided with an upper inner support and a lower inner support;
the enclosing purlin of the three inner supports adopts double-spliced H700 multiplied by 300 section steel, and the internal stay bars of the three inner supports all adopt
Figure BDA0003034753790000031
And (5) steel pipes.
Compared with the prior art, the invention has the beneficial effects that:
according to the invention, the concrete is poured after the sand is sucked and the silt is removed from the bottom of the cofferdam, the surrounding purlin and the support are pumped and installed in turn, and finally the leveling layer is constructed, so that the stability is improved, and the waterproof effect is better due to the use of the combined pile.
Drawings
FIG. 1 is a flow chart of a construction process of a combined pile cofferdam;
FIG. 2 is a schematic view of a combination pile assembly;
FIG. 3 is a sequence diagram of combined pile cofferdam piling;
reference numerals: 1-steel pipe pile; 2-steel sheet piles; 3-cushion cap sideline; 4-upstream; 5-downstream; 6-first combined pile; 7-folding the combined piles; a-the bank side; b-the side of the river.
Detailed Description
The present invention is described in detail with reference to the embodiments shown in the drawings, but it should be understood that these embodiments are not intended to limit the present invention, and those skilled in the art should understand that functional, methodological, or structural equivalents or substitutions made by these embodiments are within the scope of the present invention.
In the description of the present embodiments, it is to be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of describing the present invention and simplifying the description, but do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention.
Furthermore, the terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicit to a number of indicated technical features. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the invention, the meaning of "a plurality" is two or more unless otherwise specified.
The terms "mounted," "connected," and "coupled" are to be construed broadly and may, for example, be fixedly coupled, detachably coupled, or integrally coupled; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the creation of the present invention can be understood by those of ordinary skill in the art through specific situations.
Referring to fig. 1 to 3, an embodiment of the present invention provides a construction process of a combined pile cofferdam, including:
step one, installing a positioning pile and a guide frame, and inserting and driving a lock catch pipe pile and a steel plate pile 2.
In this embodiment, installation spud and leading truck includes: (1) installing and roughly positioning the guide frame at a specified position; (2) a dust guard is arranged at the bottom of the guide frame and then placed on the mud surface; (3) adopting a positioning pile as an auxiliary pile leg of the guide frame, penetrating the positioning pile through the guide frame and sinking the pile to a position 30-80 m below a mud surface, and (4) leveling and fixing the guide frame on the positioning pile.
In this embodiment, insert and beat hasp tubular pile and steel sheet pile 2, include: (1) blanking and processing the lock catch tubular pile; (2) hoisting and stacking the fore shaft steel pipe piles; (3) and constructing the fore shaft steel pipe pile.
The manufacturing of the locking steel pipe pile comprises lengthening of the pile and welding of the locking.
Firstly, entering a material field: the materials need to be checked and accepted when entering a field, the thickness and the performance of the materials meet the design requirements, the materials are regular and neat, and the measures of rust prevention and covering are well taken.
Transferring the locking steel pipe pile: the material size of the fore shaft steel pipe pile needs to meet the transportation requirement of a transport vehicle, the material is hoisted by a crawler crane in loading and unloading, and the material is required to be stacked neatly in the transportation process and the stacking place.
Feeding and processing of the fore shaft steel pipe pile: need to open a groove at the stake end when fore shaft steel-pipe pile connects long, during the welding, the butt welding earlier, welds stiffening plate again to at stake end preparation hanging pile hole, interface welding department keeps the straight line type, and welding seam length and height are: full weld and 5 mm. The requirement on the precision during the processing of the fore shaft steel pipe pile is high, the fore shaft mounting position can be determined by ink line springing and spot welding, then continuous double-sided foot-pasting full welding is carried out, and the thickness of a welding line is not less than 10 mm. The relative deviation between the central line of the locking notch and the central line of the tubular pile is less than or equal to 2mm, and the relative plane deviation between the top opening and the bottom opening of the locking notch is less than or equal to 4 mm.
Checking and accepting the locking steel pipe pile: after the steel pipe pile 1 fore shaft welding processing is completed, the fore shaft on two sides is tested to pass through by using 3m long and short steel plate piles 2, and 2-3 persons can pull the fore shaft to pass through. The locking notch can not pass through or the pile body has the defects of bending, twisting and the like, and the cold bending, hot knocking (the temperature does not exceed 800-1000 ℃), repair welding, riveting and the like are adopted for trimming. When the steel pipe pile 1 is connected, a groove is formed at the pile end, the reinforcing plate is welded after butt welding, and a pile hanging hole is formed at the pile end.
The hoisting and stacking method for the fore shaft steel pipe pile comprises the following steps: two-point hanging is adopted for loading and unloading the steel pipe pile 1, and attention is paid to protecting a locking notch and preventing deformation of the locking notch. The steel-pipe pile 1 is stacked on a flat and firm place, and stacked in layers, the number of stacked layers is not more than 3, sleepers are arranged between layers, the distance between the sleepers is 3-4 m, and the upper and lower layers of sleepers are on the same vertical line.
And step two, enclosing the lock catch pipe pile and the steel sheet pile 2 to form a cofferdam, and sucking sand and dredging the bottom of the cofferdam underwater.
In this embodiment, hasp tubular pile and steel sheet pile 2 enclose into the cofferdam, inhale husky desilting under water to the bottom in cofferdam, include: (1) floating mud and gravels in the cofferdam need to be removed before the bottom sealing concrete is poured, so that a harmful interlayer does not exist between the substrate and the bottom sealing concrete; (2) the sand is sucked in the cofferdam through the surface treatment of the steel pile casing, the steel pipe pile 1 and the steel sheet pile 2, only the large-range silt in the cofferdam is removed, and the silt adhered to the surface of the cofferdam is thoroughly removed by adopting high-pressure water jetting before bottom sealing.
The construction of the fore shaft steel pipe pile of the embodiment of the invention has the following construction sequence: and (3) inserting and beating 100t crawler cranes on the drilling platform from the downstream 5 of the cofferdam to the upstream 4 of the cofferdam by matching with a vibration hammer. The steel pipe pile 1 adopts a V120 hydraulic vibration hammer, and the steel plate pile 2 adopts an DZJ-120 electric vibration hammer. Before piling, grease mixture ointment is coated on the inner side, the outer side and the locking opening of the pile body to reduce the frictional resistance during inserting and beating and enhance the seepage-proofing performance. Firstly, the steel pipe pile 1 is hung to a pile position by a crawler crane for pile insertion, a measurer uses two total stations for matching and positioning, a locking notch is aligned during pile insertion, and a vibration hammer is fixed at the pile top after insertion and is hammered. Sealing treatment: since the cofferdam is large and the error of the distance between the steel pipe piles 1 is large, special treatment is required for the sealing steel pipe piles 1. When the sealing position is reached, the distance between the seals is measured, and 2-3 steel pipe piles 1 or steel sheet piles 2 can be specially processed, so that the seal can be successfully completed by locking the opening.
And step three, pouring concrete on the bottom of the cofferdam underwater by adopting a vertical conduit method.
In this embodiment, the concrete is poured underwater on the bottom of the cofferdam by using a vertical conduit method, which includes: (1) a plurality of catheters are adopted for perfusion, wherein two catheters are reserved; (2) the top of the conduit is connected with a funnel, and the funnel is connected with a concrete storage bin with a certain capacity; (3) the catheter is assembled in a trial mode before use and subjected to a water tightness experiment.
The bottom sealing concrete construction of the embodiment of the invention comprises the following steps: the thickness of the bottom sealing concrete is calculated to be 3m, the design amount is 1632m3, the underwater C30 concrete is poured by a vertical guide pipe method, the pouring is completed in two times, wherein the second pouring thickness is 50cm, and the second pouring is used for top surface leveling. The construction process comprises the following steps: clearing foundation of a cofferdam base → fixing a distributor, arranging a bottom sealing guide pipe → pouring bottom sealing concrete to a designed elevation → pumping water to the cofferdam and installing purlins and internal supports layer by layer → constructing a leveling layer.
Cofferdam foundation clearing: before the bottom sealing concrete is poured, floating mud and gravels in the cofferdam need to be removed, and no harmful interlayer is arranged between the substrate and the bottom sealing concrete. When sand is sucked in the cofferdam through surface treatment of the steel casing, the steel pipe pile 1 and the steel plate pile 2, only large-scale silt in the cofferdam is removed, the silt adhered to the surface of the cofferdam is not completely removed, and the silt must be completely removed before bottom sealing, so that the adhesive force between bottom sealing concrete and the steel casing, the steel pipe pile 1 and the steel plate pile 2 is ensured, and a water gushing channel can be prevented from being formed between the bottom sealing concrete and the bottom sealing concrete. The removal of the adhered silt is carried out by adopting high-pressure water jetting, and the whole cofferdam cannot be left; after cleaning, a diver needs to check the water. When a diver inspects, the diver needs to pay special attention to various corners, particularly the surfaces of the steel casing, the steel pipe pile 1 and the steel plate pile 2 in the range of the bottom sealing concrete need to be inspected in an important way, and mud and sand cannot be adhered to the surfaces.
Secondly, arranging a guide pipe and a measuring point: the construction process adopts a vertical conduit method for perfusion, a multi-conduit perfusion mode is adopted, and two conduits are reserved. The inner diameter of the catheter was 30cm and the wall thickness 8 mm. The distance between the guide pipes and the bottom of the river bed is 20cm, the diffusion radius of concrete is 3.5m, and the distance between the guide pipes is set to be 4.0-5.5 m. The top of the conduit is connected with a funnel, and the funnel is connected with a concrete storage bin with a certain capacity. Before pouring concrete, the hopper and the storage bin are filled with the concrete. The catheter is assembled in a trial mode before use and subjected to a water tightness experiment.
Measuring point layout principle: each catheter perfusion point is provided with a measuring point; a measuring point is arranged between the catheters; and a measuring point is arranged at the intersection point of the influence radius of the guide pipe and the guide pipe.
Pouring concrete to the designed elevation: before the first plate of concrete is sealed, a measuring hammer is used for measuring the distance between the lower opening of the guide pipe and the sand layer surface from the interior of the guide pipe, and the distance is adjusted to 10-20 cm by means of the pad beam. The first plate of concrete adopts a large hopper of 8m 3. And installing a water-isolating ball, and filling concrete into the hopper. When the large hopper is filled with concrete, the water-isolating ball is cut off, and meanwhile, the pump pipe continuously discharges the concrete, so that the first plate bottom sealing concrete pouring is completed. After the bottom sealing concrete is put down, measuring points are arranged at the opening of the guide pipe and nearby, and the buried depth and the flowing range are measured in time. When the thickness of the concrete reaches the design requirement, the guide pipe starts to move slowly along the material distribution guide frame for pouring, and the measuring hammer is used for measuring the elevation of the top surface of the concrete at any time.
The slump of the first batch of concrete of the ball pulling volume is not suitable to be too large so as to avoid that the concrete cannot form a certain gradient and cannot bury the guide pipe. The volume of the first batch of concrete was calculated using the following formula:
V=1/3×π×R2×h
r-concrete diffusion radius, 3.5m
h-burying height of concrete at bottom opening of conduit, taking 0.5m
Calculating to obtain: v is 6.5m3
And after the first plate bottom sealing concrete is successful, entering a normal pouring stage, and directly pouring concrete into the hopper. In order to ensure that the outlet of the guide pipe has a certain buried depth, the guide pipe is not lifted as much as possible when the concrete pouring is smooth; when the guide pipe needs to be lifted, the guide pipe is lifted slowly by adopting the crawler crane, the lifting height is controlled to be 50cm below the concrete surface, the concrete height at the lifting point needs to be measured on duty, the phenomenon of lifting and leaking the guide pipe is avoided, and the actual measurement depth is strictly taken as the lifting basis.
And after the concrete height at the pouring position reaches the design requirement, slowly moving the guide pipe forwards along the guide frame according to the monitoring result to carry out circulating pouring construction.
In the pouring process, the mixing proportion of the concrete is adjusted according to the actual situation on site, and the performance of the concrete is strictly controlled, so that all indexes of the concrete meet the quality requirement of the back cover. The top surface of the concrete is measured by a measuring rope at any time during pouring, and the top surface is low and not high. When pouring, the unfavorable condition of stress on the cofferdam caused by the rise of the water level in the cofferdam is not prevented, and water is pumped by a water pump to ensure the balance of the internal and external water levels. And (5) after the concrete pouring is finished, leveling the elevation by divers.
a. The initial fluidity of the concrete is more than or equal to 600 mm;
b. the slump of the first concrete is 18-20 cm, the slump is 20-22 cm during normal pouring, and the slump is strictly controlled;
c. and when the concrete pouring is close to the end, comprehensively measuring the elevation of the top surface of the concrete, monitoring the intersection of the operating radiuses of the guide pipes, the periphery of the pile casing and the periphery of the inner side of the steel cofferdam, increasing the pouring amount of the displacement guide pipes near the measuring points with lower elevations according to the result, trying to flatten the top surface of the concrete, and ensuring that the thickness of the concrete meets the requirement. When all the measuring points meet the requirements, stopping pouring concrete, pulling up a guide pipe, and flushing and stacking;
d. when bottom sealing concrete is poured, the water level inside and outside the cofferdam is changed continuously, when the initial concrete strength is lower, the permeation damage can be caused inside the concrete by the overlarge difference between the water heads inside and outside the cofferdam, in order to avoid the above condition, a three-phase submersible pump is respectively arranged inside and outside the cofferdam, water can be drained and supplemented at any time, the difference between the water heads inside and outside the cofferdam is monitored at any time within 24 hours after the bottom sealing process and the bottom sealing, and the difference is controlled within 0.3 m;
e. the buried depth of the guide pipe is controlled to be 0.8-1.0 m, the pipe is lifted in time during pouring, and the pipe is prevented from being buried in concrete to be too deep to cause pipe blockage. Pouring from the periphery of the cofferdam to the middle of the cofferdam.
f. The strength of the underwater bottom sealing concrete is not less than 50% of the design strength in 3 days, and after the concrete reaches the design strength, the next procedure construction can be carried out.
And step four, pumping water in the cofferdam for multiple times, and installing a surrounding purlin and a support after pumping water each time until the water in the cofferdam is pumped to the designed elevation.
In this embodiment, draw water in the cofferdam many times, all install one after drawing water at every turn and enclose purlin and support, draw water to the design elevation in the cofferdam until, include: (1) pumping water in the steel cofferdam after the bottom sealing concrete reaches the design strength; (2) pumping water in the cofferdam to a first elevation, and installing a first purlin and a support; (3) pumping water in the cofferdam to a second elevation, and installing a second purlin and a support; (4) pumping water in the cofferdam to a third elevation, and installing a third purlin and a support; (5) pumping water in the cofferdam to the designed elevation.
In this embodiment, the pumping work includes: and arranging the number of the water pumps according to the size of the cofferdam and the actual water depth condition in the cofferdam.
In this embodiment, pumping water to the designed elevation in the cofferdam includes: after the upper layer is ensured to be safe, the water is continuously pumped to enter the lower layer for construction; pumping water to the top surface of the bottom sealing concrete.
The cofferdam pumps water and installs enclosing purlin, internal stay layer by layer: and pumping water in the steel cofferdam and installing the enclosing purlins and the inner supports layer by layer after the bottom sealing concrete reaches the design strength. And the number of the water pumps is reasonably arranged according to the size of each cofferdam and the actual water depth in the cofferdam. An upper inner support and a lower inner support are designed in the cofferdam, the enclosing purlin is made of double-spliced 56a I-shaped steel, the inner supports are made of phi 600 multiplied by 10mm steel pipes, and the upper layer is ensured to be safe according to the principle of 'supporting before pumping' and then pumping water continuously to enter the lower layer for construction. Pumping water to the top surface of the bottom sealing concrete, removing sludge and sundries on the bottom sealing concrete, and then constructing a 50cm leveling layer.
Cofferdam water leakage treatment in the water pumping process: the water leakage of individual places can be detected by a diver launching water and the water leakage position is covered by waterproof cloth; the double-layer color strip cloth is sewn into an annular cloth belt for water leakage, the width of the annular cloth belt is the height from the top of the cofferdam to the river bed surface and is 7m, the minimum circumference is 2 times of the circumference of the cofferdam, after all the steel pipe piles with the locking notches are inserted and beaten, the cloth bag is sleeved from the top of the cofferdam, the upper opening of the cloth bag is flush with the top of the cofferdam, the lower opening of the cloth bag is paved on the river bed, and the cloth bag is compacted by a sand bag.
And arranging observation points at the four corners and the center of each side of the steel cofferdam, recording the original positions, and observing the change conditions of the displacement and the elevation of each working condition observation point. After the construction of the bottom-sealing concrete is completed, observation is performed once a day. And when the deformation value exceeds the calculated value, entering an early warning state, reinforcing the observation frequency, irrigating in the cofferdam, reducing the water pressure difference between the inner side and the outer side, and reinforcing the inner support or increasing the number of the inner supports if the deformation continues to increase.
And fifthly, carrying out leveling layer construction after pumping water and dredging.
In this embodiment, draw water and carry out leveling layer construction after the desilting, include: removing sludge and sundries on the bottom sealing concrete; and (5) constructing a leveling layer.
In this embodiment, the cofferdam is provided with an upper inner support and a lower inner support; the enclosing purlin of the three inner supports adopts double-spliced H700 multiplied by 300 section steel, and the internal stay bars of the three inner supports all adopt
Figure BDA0003034753790000101
And (5) steel pipes.
And (4) after the main piers are drained, the steel cofferdam can be dismantled. Because the pier area is in a severe scouring area, in order to reduce the influence of scouring of the bridge bearing platform area, the composite piles above the bearing platform top are removed by underwater cutting, and the composite piles below the bearing platform top are reserved. And (3) dismantling sequence: before the cofferdam is dismantled, water is injected into the cofferdam section by section according to the setting height of the inner support, then the inner support and the enclosing purlin are dismantled, the pressure difference between the inside and the outside of the cofferdam is ensured not to be too large, and finally the steel pipe pile 1 is cut underwater.
The above-listed detailed description is only a specific description of a possible embodiment of the present invention, and they are not intended to limit the scope of the present invention, and equivalent embodiments or modifications made without departing from the technical spirit of the present invention should be included in the scope of the present invention.
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.
Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

Claims (9)

1. A construction process of a combined pile cofferdam is characterized by comprising the following steps:
installing a positioning pile and a guide frame, and inserting and driving a lock catch pipe pile and a steel plate pile;
the lock catch pipe piles and the steel sheet piles form a cofferdam, and the bottom of the cofferdam is subjected to underwater sand suction and desilting;
pouring concrete on the bottom of the cofferdam underwater by adopting a vertical conduit method;
pumping water in the cofferdam for multiple times, and mounting a surrounding purlin and a support after each water pumping until the water in the cofferdam is pumped to a designed elevation;
and (5) pumping water and dredging, and then carrying out leveling layer construction.
2. The construction process of claim 1, wherein the installing the spud and the guide frame comprises:
installing and roughly positioning the guide frame at a specified position;
a dust guard is arranged at the bottom of the guide frame and then placed on the mud surface;
positioning piles are adopted as auxiliary pile legs of the guide frame, penetrate through the guide frame and are sunk to be 30-80 m below the mud surface;
and leveling and fixing the guide frame on the positioning pile.
3. The construction process according to claim 1, wherein the inserting and driving of the lock catch pipe pile and the steel sheet pile comprises:
blanking and processing the lock catch tubular pile;
hoisting and stacking the fore shaft steel pipe piles;
and constructing the fore shaft steel pipe pile.
4. The construction process according to claim 1, wherein the concrete is poured underwater on the bottom of the cofferdam by using a vertical conduit method, comprising:
a plurality of catheters are adopted for perfusion, wherein two catheters are reserved;
the top of the conduit is connected with a funnel, and the funnel is connected with a concrete storage bin with a certain capacity;
the catheter is assembled in a trial mode before use and subjected to a water tightness experiment.
5. The construction process according to claim 1, wherein the step of pumping water in the cofferdam for a plurality of times is carried out, and a surrounding purlin and a support are installed after each pumping of water until the water in the cofferdam is pumped to a designed elevation, and comprises the following steps:
pumping water in the steel cofferdam after the bottom sealing concrete reaches the design strength;
pumping water in the cofferdam to a first elevation, and installing a first purlin and a support;
pumping water in the cofferdam to a second elevation, and installing a second purlin and a support;
pumping water in the cofferdam to a third elevation, and installing a third purlin and a support;
pumping water in the cofferdam to the designed elevation.
6. The construction process according to claim 5, wherein the pumping operation comprises:
and arranging the number of the water pumps according to the size of the cofferdam and the actual water depth condition in the cofferdam.
7. The construction process according to claim 5, wherein the step of pumping water in the cofferdam to a designed elevation comprises the following steps:
after the upper layer is ensured to be safe, the water is continuously pumped to enter the lower layer for construction;
pumping water to the top surface of the bottom sealing concrete.
8. The construction process according to claim 1, wherein the leveling construction is performed after the water pumping and the desilting, and comprises the following steps:
removing sludge and sundries on the bottom sealing concrete;
and (5) constructing a leveling layer.
9. The construction process according to claim 1, wherein the cofferdam is provided with an upper and a lower three-way inner support;
the enclosing purlin of the three inner supports adopts double-spliced H700 multiplied by 300 section steel, and the internal stay bars of the three inner supports all adopt
Figure FDA0003034753780000021
And (5) steel pipes.
CN202110440396.1A 2021-01-13 2021-04-23 Construction process of combined pile cofferdam Pending CN113216228A (en)

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CN116676964A (en) * 2023-07-27 2023-09-01 中国建筑第六工程局有限公司 Bare rock pile foundation construction method under tidal action

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CN108330995A (en) * 2018-01-23 2018-07-27 四川公路桥梁建设集团有限公司 Construction method of steel sheet pile cofferdam in deep water thick silt layer environment
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JP2000192446A (en) * 1998-12-24 2000-07-11 Nippon Steel Corp Steel sheet pile and method for constructing steel-sheet pile wall
CN1837512A (en) * 2006-04-07 2006-09-27 上海市政工程设计研究总院 Combined cofferdam of steel slab pile and steel pipe pile an method for manufacturing the same
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Publication number Priority date Publication date Assignee Title
CN114250797A (en) * 2021-12-29 2022-03-29 中铁十九局集团有限公司 Underwater concrete bottom sealing construction method for steel sheet pile cofferdam in deep water area
CN116676964A (en) * 2023-07-27 2023-09-01 中国建筑第六工程局有限公司 Bare rock pile foundation construction method under tidal action

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