CN113356247A - Large deep foundation protective lock catch steel pipe pile cofferdam structure and construction method thereof - Google Patents
Large deep foundation protective lock catch steel pipe pile cofferdam structure and construction method thereof Download PDFInfo
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- CN113356247A CN113356247A CN202110657181.5A CN202110657181A CN113356247A CN 113356247 A CN113356247 A CN 113356247A CN 202110657181 A CN202110657181 A CN 202110657181A CN 113356247 A CN113356247 A CN 113356247A
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D19/00—Keeping dry foundation sites or other areas in the ground
- E02D19/02—Restraining of open water
- E02D19/04—Restraining of open water by coffer-dams, e.g. made of sheet piles
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
- E02D5/02—Sheet piles or sheet pile bulkheads
- E02D5/03—Prefabricated parts, e.g. composite sheet piles
- E02D5/04—Prefabricated parts, e.g. composite sheet piles made of steel
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
- E02D5/02—Sheet piles or sheet pile bulkheads
- E02D5/03—Prefabricated parts, e.g. composite sheet piles
- E02D5/04—Prefabricated parts, e.g. composite sheet piles made of steel
- E02D5/06—Fitted piles or other elements specially adapted for closing gaps between two sheet piles or between two walls of sheet piles
Abstract
The invention belongs to the related technical field of bridge construction, and discloses a large deep foundation protective lock catch steel pipe pile cofferdam structure, wherein the cofferdam structure is formed by connecting a plurality of lock catch steel pipe piles in series end to end, and is also provided with surrounding purlins, inner supports and force bearing pile columns, wherein the lock catch steel pipe piles are CO type steel pipe piles, the surrounding purlins are arranged on the inner side wall of the steel pipe pile cofferdam in a layered manner, and the inner supports and inclined supports are used for building a main engineering structure such as a pouring platform; in addition, the bearing pile columns are arranged at intervals along the horizontal transverse direction and the horizontal longitudinal direction of the steel pipe pile cofferdam. The invention also discloses a corresponding construction process method. By the aid of the cofferdam installation method, safe maintenance of the foundation pit under the deep-buried condition can be smoothly performed, the cofferdam is accurately, quickly and safely installed, and meanwhile, the problems that the platform is large in flexibility, the number of force-bearing members is too large and the like under the condition of super-large span are effectively solved; in addition, the cofferdam water stopping method has the advantages of being high in construction efficiency, capable of remarkably improving the cofferdam water stopping effect, beneficial to rapid construction and removal and the like.
Description
Technical Field
The invention belongs to the related technical field of bridge construction, and particularly relates to a large deep foundation protective lock catch steel pipe pile cofferdam structure and a construction method thereof.
Background
The cofferdam is used as a common temporary protection structure, can effectively avoid structural instability and water inrush risks after foundation pit excavation, and is commonly used in the engineering construction fields of bridges, buildings and the like. The currently common cofferdam form mainly comprises: an earth rock cofferdam, a double-wall steel box cofferdam, a steel sheet pile cofferdam, a steel pipe pile cofferdam, a reinforced concrete open caisson and the like.
The bay tidal flat area has the characteristics of abundant underground water, obvious fluctuation of affected water, frequent submergence of seawater during flood tide and the like, so that before construction is implemented, a proper cofferdam form is required to be selected according to project characteristics and construction environment. In the prior art, common schemes for underwater deep foundation construction include a Larsen steel sheet pile cofferdam, a lock catch steel pipe pile cofferdam, a double-wall steel box cofferdam and the like; among them, the hasp steel-pipe pile cofferdam has gained more and more attention in recent years because of having stable in structure, strong adaptability, characteristics such as high recovery rate. For example, early patents CN201910222503.6, CN201711479182.5, and CN202011587592.3, respectively, disclose some solutions applicable to such operating condition scenarios.
However, further studies have shown that the following deficiencies or drawbacks still exist in the above prior art: firstly, in the construction process, a bridge main tower bearing platform is positioned in a bay beach area, is deeply embedded and has large section size, belongs to a typical large-scale deep foundation structure of a rich water area, has extremely high safety risk, and correspondingly needs to further solve the problem of foundation pit protection under the deep embedding condition, particularly needs to optimize the difficult problem that an inner support structure needs to input more bearing members under the condition of super-large span; secondly, as the geological structure and the natural conditions of the region are complex, the region is very easily influenced by flowing sand sliding and sea tide scouring, and the water pressure of the lower part is very high along with the increase of the buried depth, the waterproof plugging of the foundation pit protection structure is more difficult to the lower part, and the water stopping performance of the cofferdam needs to be further improved correspondingly; thirdly, aiming at the condition that the construction period of the main structures such as the bearing platform, the pier body and the like is long, in order to avoid the influence on the navigation of the ship to the maximum extent, the cofferdam form which is convenient and quick to operate, safe and economical and can be quickly constructed and disassembled is very important.
Disclosure of Invention
Aiming at the defects or shortcomings of the prior art, the invention aims to provide a large deep foundation protective lock catch steel pipe pile cofferdam structure and a construction method thereof, wherein the integral structural composition of the lock catch steel pipe pile cofferdam, the arrangement mode of key modules thereof, main construction procedures and other aspects are optimally designed, so that the safe maintenance of a foundation pit under a deep burying condition can be smoothly carried out correspondingly, the accurate, quick and safe installation of the cofferdam is realized, and meanwhile, the problems of large platform flexibility, excessive arrangement quantity of force bearing members and the like under the condition of super-large span are effectively solved; in addition, the cofferdam construction method has the advantages of being high in construction efficiency, capable of remarkably improving the water stopping effect of the cofferdam, achieving multiple turnover and multi-working-surface construction, and being beneficial to rapidly achieving port recovery navigation and the like, and is particularly suitable for construction application occasions of bridge deep foundation pits in gulf beach areas and the like.
In order to achieve the purpose, according to one aspect of the invention, the cofferdam structure for the large deep foundation protective lock catch steel pipe piles is characterized in that the cofferdam structure is formed by connecting a plurality of lock catch steel pipe piles (7) in series end to end, and is further provided with a surrounding purlin (6), an inner support (4) and a force bearing pile (5):
the lock catch steel pipe piles (7) are CO steel pipe piles, wherein the C-shaped lock catch on each steel pipe pile is used for locking the O-shaped lock catch on the other adjacent steel pipe pile to form a steel pipe pile cofferdam, and the inner wall of each C-shaped lock catch is provided with a viscous elastomer waterproof layer;
the purlins (6) are arranged on the inner side wall of the steel pipe pile cofferdam in a layered mode and keep equal height with the lock catch steel pipe piles (7); the inner support (4) is installed through the surrounding purlin (6), consists of a horizontal transverse supporting steel pipe (4-1) and a horizontal longitudinal supporting steel pipe (4-2) together, and is used for building a pouring main body engineering structure together with an inclined support; in addition, the bearing pile columns (5) are arranged at intervals along the horizontal transverse direction and the horizontal longitudinal direction of the steel pipe pile cofferdam, and the top ends of the bearing pile columns are positioned below the inner supports.
Further preferably, the locking steel pipe pile (7) adopts a spiral welded pipe as a main body, and an open type steel pipe as a C-shaped lock and a closed type steel pipe as an O-shaped lock are respectively welded on two sides in the diameter direction of the spiral welded pipe.
Preferably, the C-shaped lock catch further comprises a fixing welding plate which is fixedly connected with the spiral welded pipe, is processed into a tip, and is then cut into a groove shape along the axial direction.
Preferably, the cofferdam structure further comprises a trestle, the trestle is formed by erecting and extending a main engineering structure at the upper parts of the enclosing purlin and the inner support, and comprises a branch trestle and a main trestle which are communicated with each other.
According to another aspect of the present invention, there is also provided a corresponding construction method, characterized in that it comprises the steps of:
s1 steel pipe pile manufacturing
C-shaped lock catches and O-shaped lock catches which can be mutually accommodated and locked are respectively processed on the outer walls of the spiral welded pipes, and elastic body water-resisting layers with viscosity are installed on the inner walls of the C-shaped lock catches;
s2 cofferdam closure
Butt welding the prepared steel pipe piles into required length, inserting and driving the steel pipe piles and connecting the steel pipe piles in series along the outer side of the foundation pit to form a steel pipe pile cofferdam;
s3, purlin and inner support installation
Arranging a plurality of bearing piles at intervals along the horizontal transverse direction and the horizontal longitudinal direction of the steel pipe pile cofferdam in advance; pumping water in the steel pipe pile cofferdam, excavating a foundation pit, arranging surrounding purlins and inner supports in layers according to the depth of the foundation pit, and enabling the inner supports to be located at the top ends of the bearing pile columns;
s4, construction of main engineering structure and cofferdam demolition
And after the pouring construction of the main engineering structure is completed, the rapid dismantling of the purlin, the inner support and the steel pipe pile cofferdam is sequentially executed.
Further preferably, in step S1, the steel pipe pile preferably includes a spiral welded pipe with a diameter of 630mm and a wall thickness of 10mm as a main body of the steel pipe pile, and an open type steel pipe with a diameter of 110mm and a wall thickness of 5mm is preferably welded to each of both sides in the diameter direction of the steel pipe pile as a C-shaped fastener, and a closed type steel pipe with a diameter of 100mm and a wall thickness of 5mm as an O-shaped fastener.
More preferably, in step S2, it is preferable that a bored pile placement platform is used as a construction platform for the steel pipe pile, and a plurality of vibration hammers are used to perform synchronous operation; in addition, it is preferable to use a branch trestle and a main trestle which communicate with each other as a transportation, processing and storage platform of the steel pipe pile.
As a further preferable mode, in step S2, in order to ensure the linearity of the steel pipe pile construction, it is preferable to provide a long cross beam outside the bored pile grouting platform, and then lay positioning longitudinal beams inside and outside above the long cross beam on each side; in addition, preferably, a guide frame is further arranged on the positioning longitudinal beam, the first steel pipe pile is driven to a specified depth by inserting through the guide frame, then the guide frame is moved to position a second steel pipe pile and driven to be flush with the first steel pipe pile, and then the first steel pipe pile is returned to drive the rest part of the first steel pipe pile in place by inserting; and moving the guide frame again to position the third steel pipe pile, inserting and driving the third steel pipe pile to be flush with the second steel pipe pile, returning to the second steel pipe pile, inserting and driving the rest part in place … …, and circulating the steps until the cofferdam of the steel pipe pile is closed.
As a further preference, in step S2, the guide frame preferably includes an openable structure and a fixing clip, wherein the openable structure is made of an i-beam with semicircular steel plates welded to the upper and lower surfaces thereof, respectively, and is hinged by a latch; the fixing clamping piece is formed by vertically installing a steel plate with a long strip hole and a Z-shaped steel plate, and the fixing and up-and-down movement adjustment between the steel plate and the Z-shaped steel plate are realized by adopting a screw rod arranged in the long strip hole.
Further preferably, in step S3, before the purlin is constructed, a circle of reinforced concrete is preferably cast along the height direction of the purlin, and a layer of steel wire mesh is preferably built in, so as to ensure the degree of adhesion between the purlin and the steel pipe pile cofferdam.
Preferably, in step S3, after the installation of the purlin and the inner support is completed, a bottom-sealing concrete platform is preferably set up and a multi-conduit pouring method is adopted to perform bottom-sealing operation on the bottom of the foundation pit; the pouring positions of the pit bottom guide pipes are processed into funnel shapes one by one according to a transverse and longitudinal spacing mode, then the guide pipes are correspondingly inserted into all funnel areas, and the top of each guide pipe is provided with a collecting hopper for synchronous operation.
Further preferably, in step S4, it is preferable that a reinforced concrete auxiliary cofferdam is further provided along the periphery of the main body work structure, the reinforced concrete auxiliary cofferdam being provided along the periphery of the top surface of the main body work structure and being at the same height as the steel-pipe pile cofferdam; and after the concrete is cured, pulling out, decomposing and returning the steel pipe pile cofferdam.
Generally, compared with the prior art, the above technical solution conceived by the present invention has the following beneficial effects:
1. according to the cofferdam construction method, the overall structure composition of the cofferdam, the construction mode of the cofferdam and the like are researched and improved, so that the problem of foundation pit maintenance under the deep burying condition can be further improved, the cofferdam can be accurately, quickly and safely installed, the problems of large platform flexibility, large arrangement quantity of bearing members and the like under the condition of super-large span can be effectively solved through the specially arranged bearing piles, and the construction safety is ensured;
2. the invention also redesigns the concrete structural design of the adopted steel pipe pile, positioning construction and other aspects, correspondingly can obviously improve the water stopping effect of the steel pipe pile cofferdam, can realize repeated turnover and multi-working-surface construction, and obtains higher accuracy while greatly improving the construction efficiency;
3. the reinforced concrete auxiliary cofferdam is arranged, so that the steel pipe pile cofferdam is conveniently dismantled as soon as possible in the construction period, the construction cost is reduced, and meanwhile, the reinforced concrete auxiliary cofferdam can serve as a permanent structure to play a role in safety protection of a main body;
4. the invention also fully combines the construction environment of the overseas beach area, researches and improves the whole construction process and the main steps thereof such as cofferdam pit bottom closing operation, dismantling operation and the like, accordingly, the effects of high-efficiency construction and quick dismantling can be obtained, and the port recovery navigation can be realized more quickly, so the invention is particularly suitable for the application occasions of the construction of the bridge deep foundation pit in the gulf beach area and the like.
Drawings
FIG. 1 is a schematic perspective view of a large deep foundation protective lock catch steel pipe pile cofferdam structure constructed according to the invention;
FIG. 2 is a schematic plan view of the cofferdam structure shown in FIG. 1;
FIG. 3 is a schematic structural view of a guide frame for positioning construction of a steel pipe pile according to a preferred embodiment of the present invention;
fig. 4 is a schematic view for exemplarily showing the entire cofferdam construction process in accordance with another preferred embodiment of the present invention.
The same reference numbers will be used throughout the drawings to refer to the same or like elements or structures, wherein:
1: pouring a platform; 2: a trestle; 2-1: a main trestle; 2-2: a trestle is supported; 3: i-shaped steel for lapping; 4: an inner support; 4-1: transversely supporting the steel pipe; 4-2: longitudinally supporting the steel pipe; 5: a bearing pile column; 6: enclosing purlins; 7: a steel pipe pile cofferdam; 8: obliquely supporting; 9: filling concrete between pipes; 11: i-shaped steel; 11-1: semicircular notches are formed; 11-2: a round notch; 12: a bolt; 13-1: a steel plate with a long hole; 13-2: a Z-shaped steel plate; 13-3: and (5) fixing the bolt.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Referring to fig. 1, fig. 1 is a schematic perspective view of a cofferdam structure of a large deep foundation protective lock catch steel pipe pile constructed according to the present invention. As shown in fig. 1, the cofferdam structure is formed by connecting a plurality of lock catch steel pipe piles 7 end to end in series, and is further provided with a surrounding purlin 6, an inner support 4, a force bearing pile 5 and the like. In addition, the trestle 2 can be formed by erecting and extending a main engineering structure (shown as a pouring platform 1 in the figure) on the upper parts of the enclosing purlin 6 and the inner support 4, wherein the trestle can comprise a branch trestle 2-2 and a main trestle 2-1 which are communicated with each other.
The cofferdam structure is explained in more detail below with reference to fig. 2.
The lock catch steel pipe piles 7 adopt CO type steel pipe piles, wherein a C-shaped lock catch on each steel pipe pile is used for locking an O-shaped lock catch on another adjacent steel pipe pile to form a steel pipe pile cofferdam, and an elastic body waterproof layer with viscosity is arranged on the inner wall of the C-shaped lock catch.
According to a preferred embodiment of the invention, the C-shaped lock catch is further provided with a fixed welding plate which is fixedly connected with the spiral welded pipe, is processed into a tip, and is then cut into a groove shape along the axial direction.
Due to the design, on one hand, the drilling resistance can be reduced, the construction speed is improved, and the C-shaped lock catch is not easy to enter a covering object in a cavity of the straight-end lock catch, so that an O-shaped lock catch can better enter the cavity, and meanwhile, impurities possibly occurring in the CO lock catch cavity are less; on the other hand, by additionally arranging the elastic body water-proof layer with viscosity, the elastic body water-proof layer is difficult to strip once contacting with any object; simultaneously the elastomer ductility is strong, can fill the clearance that probably exists between the CO hasp better, and this elastomer has the self-resuming function simultaneously, no matter be the sword and draw or tear, the homoenergetic is just as original, once put into use, can come and go repetitious usage.
The purlins 6 are arranged on the inner side wall of the steel pipe pile cofferdam in a layered mode and keep equal height with the lock catch steel pipe piles 7; the inner support 4 is installed through a surrounding purlin 6, consists of a horizontal transverse support steel pipe 4-1 and a horizontal longitudinal support steel pipe 4-2, and is used for building a main engineering structure such as a pouring platform 1 or a pier body together with an inclined support 8.
The whole cofferdam construction process will be specifically described with reference to fig. 4.
First, a steel pipe pile manufacturing step is performed.
In this step, a C-shaped lock catch and an O-shaped lock catch which can be accommodated and locked with each other are respectively machined on the outer wall of the steel pipe pile body, and an elastic body waterproof layer with viscosity is installed on the inner wall of the C-shaped lock catch. For example, a spiral welded pipe with a diameter of 630mm and a wall thickness of 10mm is often used as a main body of the steel pipe pile, an open steel pipe with a diameter of 110mm and a wall thickness of 5mm and a closed steel pipe with a diameter of 100mm and a wall thickness of 5mm are respectively welded on two sides in the diameter direction to form a snap-in connection structure of the CO-type steel pipe pile, and in order to prevent the C-type lock catch from deforming, a steel plate can be welded between the main body and the C-type lock catch at an interval of 50cm in the axial direction of the steel pipe pile to form a fixed structure.
In addition, the steel pipe pile cofferdam adopts a rectangular structure, the number of the cofferdam in the longitudinal direction and the transverse direction is determined before construction, the connection structure of the pipe piles at the corners is guaranteed to be distributed at right angles as far as possible, and the clear distance between the currently constructed pipe pile and the head pile is measured accurately by 2-3 cofferdams before closure of the steel pipe pile cofferdam, so that the number and the connection angle of the pipe piles can be adjusted in time.
When the steel pipe pile cofferdam is arranged along the outer side of the main engineering structure in the foundation pit in a closed manner, the size of the cofferdam from the outer side of the main engineering structure after general forming is preferably 1-2m, the exposed length of the steel pipe pile is more than 0.7m of the maximum tide (rising) water level, and the total length of the steel pipe pile is the sum of the minimum embedding depth of the overturning resisting length and the non-embedding length. The length of the steel pipe pile is generally 12 m/pile, and the lengthening treatment is required to be done in advance on site before pile sinking.
Next, the cofferdam closure step is performed.
In this step, the steel pipe piles are butt-welded to a desired length, and the steel pipe piles are driven and connected in series along the outside of the foundation pit to form a steel pipe pile cofferdam.
Particularly, before the construction of the steel pipe pile cofferdam, a bored pile pouring platform can be fully utilized as a vibration hammer construction operation platform, the synchronous operation of a plurality of vibration hammers is realized, and a trestle and a branch trestle are fully utilized as a pipe pile transportation, processing and storage platform, so that the purpose of rapid construction of the cofferdam is ensured, and conditions are created for the early development of subsequent work.
According to a preferred embodiment of the invention, in order to ensure the linearity of the steel pipe pile construction, a long cross beam is preferably arranged on the outer side of a bored pile pouring platform, and then positioning longitudinal beams are respectively distributed on the inner side and the outer side above the long cross beam on each side; in addition, preferably, a guide frame is further arranged on the positioning longitudinal beam, the first steel pipe pile is driven to a specified depth by inserting through the guide frame, then the guide frame is moved to position a second steel pipe pile and driven to be flush with the first steel pipe pile, and then the first steel pipe pile is returned to drive the rest part of the first steel pipe pile in place by inserting; and moving the guide frame again to position the third steel pipe pile, inserting and driving the third steel pipe pile to be flush with the second steel pipe pile, returning to the second steel pipe pile, inserting and driving the rest part in place … …, and circulating the steps until the cofferdam of the steel pipe pile is closed.
Referring to fig. 3, there is shown a schematic structural view of a guide frame for positioning construction of a steel pipe pile according to another preferred embodiment of the present invention.
As shown in fig. 3, the guide frame preferably includes an openable structure and a fixing clip, wherein the openable structure is made of an i-beam 11 with semicircular steel plates welded to the upper and lower surfaces thereof, respectively, and is hinged by a latch 12; the fixing clamping piece is formed by vertically installing a steel plate 13-1 with a long strip hole and a Z-shaped steel plate 13-2, and the fixing and up-and-down movement adjustment between the steel plate and the Z-shaped steel plate are realized by adopting a screw 13-3 arranged in the long strip hole.
More specifically, for example, an I20I-shaped steel can be welded on the upper and lower surfaces thereof with two steel plates which are 10mm thick and are sequentially cut into 8 semicircles with diameters of 630mm and 110mm, and then one ends of the two parts are hinged through a bolt, thereby forming an openable and closable structure; in addition, a steel pipe pile opening fixing clamping piece is arranged on the upper surface of the steel plate on the other side, the fixing clamping piece is vertically welded with a panel through a mother plate with a long strip hole, then two screws with the interval of 60mm are welded on the Z-shaped steel plate and fixed with the mother plate hole, and the fixing or loosening of the steel pipe pile opening is realized through the up-and-down movement of a fixing bolt in the long strip hole of the mother plate; and two round holes with the diameter of 110mm are arranged at the middle holes with the diameter of 630mm on the upper surface and the lower surface of the guide frame along the normal direction of the axis, so that the steel pipe pile can be conveniently positioned for use in turning.
In the construction process, the guide frame can be installed on a constructed steel pipe pile, wherein one end with a pin shaft is arranged on the construction side of the next pipe pile, the pipe pile fixing clamping piece is used for fixing the pipe orifice, and then the constructed steel pipe pile is inserted through the notch for pile sinking construction; when the 1 st to 2 nd steel pipe piles are constructed, fixing the lower steel plate of the guide frame and the upper flange plate of the guide longitudinal beam by using the C-shaped lock catch; when a first tubular pile at a corner is constructed, the pin shaft is continuously kept at the same construction side, but a middle main hole is required to be arranged on the last tubular pile in the previous row, a C-shaped lock catch is also adopted to fix a lower steel plate of the guide frame and an upper flange plate of the guide longitudinal beam, and then the tubular pile is inserted into a cut hole for construction; the flange plate is fixed or used when the first tubular pile is arranged at the corner.
Next, the installation steps of the purlin and the inner support are carried out.
In the step, a plurality of bearing pile columns are arranged at intervals along the horizontal transverse direction and the horizontal longitudinal direction of the steel pipe pile cofferdam in advance; and then, pumping water in the steel pipe pile cofferdam, excavating a foundation pit, arranging surrounding purlins and inner supports in layers according to the depth of the foundation pit, and enabling the inner supports to be located at the top ends of the bearing pile columns.
More specifically, the steel pipe pile cofferdam can be provided with purlins and inner supports for construction in layers according to the embedding depth of the structure, generally, one purlin is arranged at the top of the cofferdam and the top of a foundation respectively, the height of each purlin is as high as that of the steel pipe pile cofferdam, and a bottom sealing concrete platform and the construction trestle extending out of the cofferdam are convenient to connect with a construction trestle at the later stage; when the distance between the upper and lower layers of purlins is large, the number of the purlins is properly increased in the middle of the cofferdam according to the simple calculation condition, and the safety of the cofferdam structure is met.
For example, a surrounding purlin supporting platform can be arranged on the inner side wall of the steel pipe pile cofferdam according to the distance between every 5 pipe piles, 1I 20I-steel is horizontally welded on each platform along the diameter direction of the pipe pile, and then an I20I-steel is welded between the pipe pile and the horizontal I-steel to serve as an inclined strut; in order to ensure the attaching degree of the enclosing purlin and the steel pipe pile cofferdam, before the construction of the enclosing purlin, a circle of thin-layer reinforced concrete is preferably constructed in the construction height direction of the enclosing purlin, the concrete at the diameter position of the pipe pile is 10cm in thickness and 70cm in height, and a steel wire mesh layer is arranged in the steel wire mesh cofferdam, so that the steel wire mesh is not fixed with the pipe pile for the convenience of the subsequent pipe pile and concrete removal.
Mounting enclosing purlins after concrete pouring is finished, and welding steel plates at two ends of the enclosing purlins to prevent the auxiliary close-fitting concrete from being damaged; the purlin can be horizontally placed by adopting double-spliced I70I-steel, so that the flange plate of the I-steel is ensured to be closely attached to the auxiliary concrete of the steel pipe pile; when the purlins are installed, firstly installing a long purlin, secondly installing a short purlin, installing an inner support double-spliced I70I-steel diagonal support after the purlins are closed into a ring, then installing a short 630mm diameter steel pipe pile on the long purlin as a horizontal cross brace, ensuring that the cross brace is located in a bearing column constructed in advance, and finally installing a 630mm diameter steel pipe pile horizontal long support; the enclosing purlins are connected with each other in a welding mode, the inner supports are connected with the enclosing purlins in a welding mode, the horizontal long supports are connected with the short supports in a welding mode, the circular connectors are machined in the field in advance, and the horizontal inner support steel pipes of the rest positions are connected through flanges. In addition, in order to ensure the smooth installation of the enclosing purlin structure, the steel plate, the distributed I-steel, the Bailey beam, the steel protecting cylinder, the drilling platform pipe pile and the like above the drilling pile platform can be detached in advance.
In this step, the bearing pile column can adopt the drilling bored concrete pile for diameter 100cm, and the construction is carried out immediately after the pile foundation construction is accomplished, lays between the pile foundation, wherein can arrange 3 rows along cofferdam longitudinal direction for example, arrange 2 rows along the cofferdam transverse direction, and the effective pile of pile foundation is long to inner support top, and the construction is dug out in step with the close concrete placement in cofferdam before enclosing purlin installation.
After the enclosing purlin and the inner support are installed, foundation pit soil excavation or sand pumping operation is carried out, leveling is carried out after the bottom of a pit reaches the excavation depth, bottom sealing operation is carried out after a bottom sealing concrete platform is built, and a Bailey beam, distribution I-steel, steel plates and the like are respectively built on the concrete bottom sealing platform from bottom to top above the enclosing purlin and the inner support.
According to another preferred embodiment of the invention, after the surrounding purlin and the inner support are installed, a bottom sealing concrete platform is preferably erected and a multi-conduit pouring method is adopted to perform bottom sealing operation on the bottom of the foundation pit; the pouring positions of the pit bottom guide pipes are processed into funnel shapes one by one according to a transverse and longitudinal spacing mode, then the guide pipes are correspondingly inserted into all funnel areas, and the top of each guide pipe is provided with a collecting hopper for synchronous operation.
And after the bottom sealing concrete is finally set and has certain strength, performing drainage operation in the cofferdam, removing the bottom sealing concrete pouring platform and the bearing pile column below the inner support at the same time, performing construction of the enclosing purlin and the inner support at the lower part of the cofferdam, and performing reinforcement of a bearing platform, formwork installation, concrete pouring, maintenance construction and the like.
And finally, constructing a main engineering structure and dismantling the cofferdam.
In the step, after the pouring construction of the main engineering structure is completed, the enclosing purlin, the inner support and the steel pipe pile cofferdam are quickly dismantled in sequence.
More specifically, after concrete pouring is completed on a main engineering structure such as a bearing platform or a pier body, the enclosing purlin and the inner support are detached; when binding pier body steel bars, firstly arranging a reinforced concrete cofferdam along the periphery of the top surface of the bearing platform, wherein the cofferdam can be made of C40 marine concrete, the thickness of the cofferdam is 40cm, the height of the cofferdam is the same as the designed elevation of the top surface of the steel pipe pile cofferdam, and the inner surface and the outer surface of the cofferdam are subjected to seawater erosion prevention treatment after a template is removed; and after the strength of the concrete reaches a certain strength, removing the steel pipe pile to assist in closely adhering the concrete, and then pulling out, decomposing and returning the steel pipe pile cofferdam.
In conclusion, according to the large deep foundation protective lock catch steel pipe pile cofferdam structure and the construction method thereof, the problem of foundation pit enclosure under deep burying conditions can be effectively solved, accurate, rapid and safe installation is realized, the problem that more force bearing members need to be input under the condition of ultra-large span of the inner support structure is solved, the cost input is reduced, and rapid construction is realized. In addition, the construction period of main structures such as a bearing platform and a pier body below underwater or a soil layer is long, the cofferdam is likely to have poor water plugging effect, the structural composition and the processing mode of the steel pipe pile are improved, and meanwhile, the supplementary cofferdam is arranged to realize the rapid dismantling of the steel pipe pile cofferdam, so that pier body protection is realized, and the smooth early navigation of a ship is facilitated.
It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (10)
1. The utility model provides a big deep basal protection hasp steel-pipe pile cofferdam structure which characterized in that, this cofferdam structure comprises many hasp steel-pipe piles (7) end to end series connection, still disposes enclosing purlin (6), interior support (4) and load stake (5):
the lock catch steel pipe piles (7) are CO steel pipe piles, wherein the C-shaped lock catch on each steel pipe pile is used for locking the O-shaped lock catch on the other adjacent steel pipe pile to form a steel pipe pile cofferdam, and the inner wall of each C-shaped lock catch is provided with a viscous elastomer waterproof layer;
the purlins (6) are arranged on the inner side wall of the steel pipe pile cofferdam in a layered mode and keep equal height with the lock catch steel pipe piles (7); the inner support (4) is installed through the surrounding purlin (6), consists of a horizontal transverse supporting steel pipe (4-1) and a horizontal longitudinal supporting steel pipe (4-2) together, and is used for building a pouring main body engineering structure together with an inclined support; in addition, the bearing pile columns (5) are arranged at intervals along the horizontal transverse direction and the horizontal longitudinal direction of the steel pipe pile cofferdam, and the top ends of the bearing pile columns are positioned below the inner supports.
2. The large deep foundation protection hasp steel pipe pile cofferdam structure of claim 1, wherein the hasp steel pipe pile (7) adopts spiral welded pipe as main body, and an open type steel pipe as C-shaped hasp and a closed type steel pipe as O-shaped hasp are welded respectively at two sides along its diameter direction; the C-shaped lock catch is further provided with a fixed welding plate, the fixed welding plate is fixedly connected with the spiral welding pipe and is processed into a tip, and then the fixed welding plate is cut into a groove shape along the axial direction.
3. The cofferdam structure of steel pipe piles with large deep foundation protections and locks as claimed in claim 1 or 2, wherein the cofferdam structure further comprises a trestle, which is formed by outwardly erecting and extending main engineering structures positioned at the upper parts of the enclosing purlin and the inner support, and comprises a branch trestle and a main trestle which are communicated with each other.
4. A construction method of a large deep foundation protection lock catch steel pipe pile cofferdam structure as claimed in any one of claims 1-4, characterized in that the method comprises the following steps:
s1 steel pipe pile manufacturing
C-shaped lock catches and O-shaped lock catches which can be mutually accommodated and locked are respectively processed on the outer walls of the spiral welded pipes, and elastic body water-resisting layers with viscosity are installed on the inner walls of the C-shaped lock catches;
s2 cofferdam closure
Butt welding the prepared steel pipe piles into required length, inserting and driving the steel pipe piles and connecting the steel pipe piles in series along the outer side of the foundation pit to form a steel pipe pile cofferdam;
s3, purlin and inner support installation
Arranging a plurality of bearing piles at intervals along the horizontal transverse direction and the horizontal longitudinal direction of the steel pipe pile cofferdam in advance; pumping water in the steel pipe pile cofferdam, excavating a foundation pit, arranging surrounding purlins and inner supports in layers according to the depth of the foundation pit, and enabling the inner supports to be located at the top ends of the bearing pile columns;
s4, construction of main engineering structure and cofferdam demolition
And after the pouring construction of the main engineering structure is completed, the rapid dismantling of the purlin, the inner support and the steel pipe pile cofferdam is sequentially executed.
5. The construction method according to claim 4, wherein in step S1, the steel pipe pile preferably uses a spiral welded pipe with a diameter of 630mm and a wall thickness of 10mm as a main body of the steel pipe pile, and an open type steel pipe with a diameter of 110mm and a wall thickness of 5mm is preferably welded along both sides in the diameter direction thereof as a C-shaped fastener, and a closed type steel pipe with a diameter of 100mm and a wall thickness of 5mm as an O-shaped fastener.
6. The construction method according to claim 4 or 5, wherein in step S2, in order to ensure the linearity of the steel pipe pile construction, it is preferable to provide a long beam outside the bored pile platform, and then lay positioning longitudinal beams inside and outside the long beam on each side; in addition, preferably, a guide frame is further arranged on the positioning longitudinal beam, the first steel pipe pile is driven to a specified depth by inserting through the guide frame, then the guide frame is moved to position a second steel pipe pile and driven to be flush with the first steel pipe pile, and then the first steel pipe pile is returned to drive the rest part of the first steel pipe pile in place by inserting; and moving the guide frame again to position the third steel pipe pile, inserting and driving the third steel pipe pile to be flush with the second steel pipe pile, returning to the second steel pipe pile, inserting and driving the rest part in place … …, and circulating the steps until the cofferdam of the steel pipe pile is closed.
7. The construction method as claimed in claim 6, wherein the guide frame preferably includes an openable structure and a fixing clip, wherein the openable structure is made of an i-beam having semicircular steel plates welded to upper and lower surfaces thereof, respectively, and hinged by a latch, at step S2; the fixing clamping piece is formed by vertically installing a steel plate with a long strip hole and a Z-shaped steel plate, and the fixing and up-and-down movement adjustment between the steel plate and the Z-shaped steel plate are realized by adopting a screw rod arranged in the long strip hole.
8. The construction method according to any one of claims 4 to 7, wherein in step S3, before the purlin is constructed, a circle of reinforced concrete is preferably cast along the height direction of the purlin, and a layer of steel wire mesh sheets is embedded, so as to ensure the fit between the purlin and the steel pipe pile cofferdam.
9. The construction method according to any one of claims 4 to 8, wherein in step S3, after the enclosing purlin and the inner support are installed, a bottom-sealing concrete platform is preferably set up and a multi-conduit pouring method is adopted to perform bottom sealing operation on the bottom of the foundation pit; the pouring positions of the pit bottom guide pipes are processed into funnel shapes one by one according to a transverse and longitudinal spacing mode, then the guide pipes are correspondingly inserted into all funnel areas, and the top of each guide pipe is provided with a collecting hopper for synchronous operation.
10. The construction method according to any one of claims 4 to 9, wherein in step S4, a reinforced concrete auxiliary cofferdam is preferably further provided along a peripheral edge of the main works structure, along a peripheral edge of the top surface of the main works structure, and at the same height as the steel pipe pile cofferdam; and after the concrete is cured, pulling out, decomposing and returning the steel pipe pile cofferdam.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115045310A (en) * | 2022-07-25 | 2022-09-13 | 中交一公局第八工程有限公司 | Steel pipe pile cofferdam construction method |
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| CN204151803U (en) * | 2014-05-21 | 2015-02-11 | 中交二航局第四工程有限公司 | A kind of opening locked steel tube pilecofferdam |
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| CN211257026U (en) * | 2019-11-21 | 2020-08-14 | 深圳市东深工程有限公司 | Steel sheet pile cofferdam |
| CN112854267A (en) * | 2021-01-05 | 2021-05-28 | 中铁大桥局集团有限公司 | Construction method of high-fall deepwater rock-socketed foundation |
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| CN204151803U (en) * | 2014-05-21 | 2015-02-11 | 中交二航局第四工程有限公司 | A kind of opening locked steel tube pilecofferdam |
| CN107905245A (en) * | 2017-12-29 | 2018-04-13 | 中交路桥华南工程有限公司 | Ultra-deep-water cofferdam fore shaft steel pipe pile construction method |
| CN211257026U (en) * | 2019-11-21 | 2020-08-14 | 深圳市东深工程有限公司 | Steel sheet pile cofferdam |
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| CN115045310A (en) * | 2022-07-25 | 2022-09-13 | 中交一公局第八工程有限公司 | Steel pipe pile cofferdam construction method |
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