A construction method for underwater anti-floating and anti-cracking arch beam-bottom plate structure

Abstract

The invention discloses a construction method of an underwater anti-floating and anti-cracking arch beam-bottom plate structure, comprising the following steps: (1) driving steel pipe piles for retaining soil on both sides of the river channel in the underwater foundation pit area, and pouring concrete in double rows of steel pipe piles to form anti-sliding support for the bank slope; (2) desilting between the two rows of steel pipe piles in sections; (3) arranging a plurality of steel pipe arch beams on the cushion layer; (4) providing a separation enclosure on both sides of the steel pipe arch beam, using a conduit method to pour C20 concrete 300cm, or using underwater self-leveling non-dispersed concrete to pour concrete; (5) providing anchor rods at the roots of both ends of the steel pipe arch beam, and the anchor rods pass through the poured concrete; (6) arranging a transverse prestressed steel beam on the poured concrete, and the transverse prestressed steel beam is fixed on the anchor rod; (7) pouring low-heat C30 concrete on the concrete until the design requirements are met. The invention solves the problem of large-scale sloping, large-scale excavation and large-scale replacement and filling underwater, and saves engineering workload. Underwater construction avoids the significant investment and risks of slope stabilization and anti-seepage treatment in dry land construction.

Description

Technical Field

[0001] The invention relates to a construction method of an underwater anti-floating and anti-cracking arch beam-bottom plate structure, belonging to the field of water conservancy engineering. Background Art

[0002] Tunnels or bridges can be used to cross rivers. In order to solve land use and urban planning issues, there are more and more underground tunnels crossing rivers in cities. Due to terrain reasons, lead length and investment decision-making reasons, there are a large number of shallow tunnel engineering problems in rivers. The anti-floating and anti-seepage safety during the construction and operation periods, and the feasibility of the construction plan are the key and difficult points. Similarly, large-volume underwater concrete projects with anti-floating and zoning implementation requirements are also common in projects such as locks, marine engineering bottom plates, and hydropower station cofferdam foundations. In the current existing technology, temporary river channels are excavated near the tunnel line for diversion to ensure the smooth flow of the river. At the same time, dry land construction protection measures are taken or backfilling and covering are used to solve existing problems; during the tunnel shield process, due to the excessive depth of the silt layer, the shield machine sinks and the tunnel floats during the shield process. These problems can be solved comprehensively by using high-pressure rotary grouting foundation reinforcement under dry land conditions. The method of digging temporary river channels for diversion requires large engineering workload and requires increasing the land space to accommodate the setting up of temporary river channels. For example, 201910978416.3 A construction method of earth pressure shield crossing a river channel in a water bag pebble mixed soil layer and 201910780497.6 A construction process of a tunnel under a river both use the method of excavating temporary river channels and have a long construction period, which has affected the progress of the project construction to a certain extent.

[0003] Common methods for reinforcing soft soils such as silt include high-pressure jet grouting, pressure grouting, and in-situ cement mixing. However, the shallow buried area does not have sufficient coverage and is underwater, so the above methods are difficult to implement. The underwater sludge suction replacement process is a deep underwater foundation pit problem. On the one hand, it is necessary to solve the slope stability and reduce the excavation workload; on the other hand, it is necessary to solve the river bank slope stability and the stability of surrounding buildings. The foundation pit stability problem with weak layers is particularly complex.

[0004] Patent No.: 202110961945.X A method for constructing a tunnel foundation pit across a non-navigable river, using river backfill and foundation pit backfill methods. This method can only be used in rivers that can be cut off and cut off from navigation; it cannot solve the problem of instability caused by shallow burial in the muddy riverbed; backfill can only solve the temporary anti-floating problem during the construction period, but cannot solve the permanent anti-floating problem after the excavation is completed. Therefore, it can only solve the temporary anti-floating problem, with a large workload and a large impact on the river. Summary of the invention

[0005] Purpose of the invention: In order to overcome the shortcomings of the prior art, the present invention provides a construction method for an underwater anti-floating and anti-cracking arch beam-bottom plate structure, which solves the problems of large-scale slope reduction, large-scale excavation and large-scale replacement and replacement, and saves engineering work. Underwater construction avoids the significant investment and risk of slope stability and anti-seepage treatment in dry land construction.

[0006] Technical solution: To solve the above technical problems, a construction method of an underwater anti-floating and anti-cracking arch beam-bottom plate structure is provided, comprising the following steps:

[0007] (1) Steel pipe piles for retaining soil are driven into the river banks in the underwater foundation pit area. The steel pipe piles are arranged in double rows and concrete is poured into the double rows of steel pipe piles to form anti-sliding support for the bank slope;

[0008] (2) According to the design requirements, large slope reduction and silt removal are carried out at the embankment between the two rows of steel pipe piles. After the layout, the bottom filling bags are laid on the embankment, and the bottom leveling layer concrete is poured. The thickness of the bottom filling bags is 30-50cm, and the elevation difference of the top surface of the filling bags is controlled within 10cm. After the strength reaches 80% of the standard strength, continue to fill the next layer of concrete bags. The height of the embankment is the bottom surface height of the second phase concrete of the top plate;

[0009] (3) All dikes are filled in sequence. After two dikes are completed, the area between the two dikes is desilted and acceptance is conducted after the base surface is basically reached;

[0010] (4) After the arch beam is manufactured, it is floated to the designated location in a suspended state. The arch beam arch foot has anchor plates and anchor beams to ensure stability in the water. After it is in place, hollow precast concrete is used to level the part. A certain amount of cement-based grouting material is added to the pipe to enhance its stability. Grouting holes are provided on the upper part of the steel pipe arch beam.

[0011] (5) Set up enclosures on both sides of the steel tube arch beam;

[0012] (6) Ordinary underwater concrete construction is carried out between the two dikes, and grouting pipes are reserved at the interface with the dike and the bottom to bury the arch beam intactly in the first phase concrete;

[0013] (7) Anchor rods are provided at the roots of both sides of the steel tube arch beam, and the anchor rods pass through the poured concrete;

[0014] (8) A transverse prestressed steel beam is arranged on the poured concrete, and the transverse prestressed steel beam is fixed on the anchor rod;

[0015] (9) Pour low-heat C30 concrete on the concrete until it meets the design requirements.

[0016] Preferably, the enclosure includes traction pipes stacked from bottom to top, the traction pipes include a main pipe located in the center and grouting pipes arranged circumferentially around the main pipe, the grouting pipes are covered with a base, the main pipe is covered with a clamp, the clamp is connected to the base through a connecting plate, and the connecting plate is hinged to the clamp and the base respectively.

[0017] As a preferred method, according to the traction pipe process, first use a drilling rig to drill a pilot hole according to the designed route, then pull back to expand the hole diameter to the diameter required for laying the traction main pipe and grouting flower pipe, fix the main pipe and grouting flower pipe to the traction head, and pull the pipe back; the main pipe is connected by hot melt, the grouting flower pipe is connected by threaded sleeve, and the main pipe and the steel flower pipe are connected by clamps and hinges; after the traction is in place, the traction equipment is removed to ensure that the main pipe does not move, and the steel flower pipe is pulled and stretched to rotate the connection hinge and open the grouting flower pipe.

[0018] Preferably, after the bottom leveling layer concrete is poured in step (2), bottom filling bags are continuously arranged on both sides to form a cavity in the middle, and the cover plate concrete is poured in the cavity.

[0019] In the present invention, a part deviating from the main channel is selected to set up a filled concrete bag dike; the flat filling bag is generally used to fill water and sand, and this process is used to fill underwater non-dispersed self-leveling concrete; a reasonable number and distribution of feed ports are set on the top surface of the filling bag to facilitate the filling of the entire area without vibration. First, the dike part is staked out, dredged, measured and verified, and the dike control points are staked out; the baseline is set: the pre-set concrete blocks are sunk to the specified position, and underwater silver lights are set as control points with an accuracy of 50cm; the four-side control lines are laid out based on the control points, and the reflective cursors of the heavy hammer system are placed along the lines to facilitate the arrangement of the filling bags. The filling bags are arranged and filled with concrete. When the strength of the next layer of concrete reaches 80%, the previous layer of concrete is filled until the dike is completed. The normal underwater concrete funnel method construction is completed in the first or second phase in the separation dike; each area can be completed in turn to form a concrete surface with the same height as the separation dike; the filling bags in the length direction of the tunnel are laid and filled with underwater non-dispersible concrete, which are completed in turn to form a cofferdam. The formwork is used in the cofferdam to cast the cover concrete in the formwork partitions. The concrete is cast by underwater non-dispersible concrete or funnel method. In terms of structure, reinforced steel pipe arch ribs, steel beams, and anchor rods are used.

[0020] In the present invention, arch beams and prestressed steel beams are used as two alternative measures for beam and slab reinforcement. The arch beams are increased in arch foot and anchor plate, which can improve the effect of anchoring at both ends. The arch beam structure can reduce the amount of steel used, and solve the anti-floating problem through the tension of the arch beam. The prestressed steel beam method solves the problem of large anti-floating bending moment in the middle part through the bending resistance of the beam, and the use of prestress can also reduce the amount of steel used. The arch beam + arch foot anchor plate is buried in the first-phase concrete, and the complicated connection problem between the anchor rod, anchor beam and steel beam is solved through the force between the anchor plate and concrete. In the form of arch beam + bottom plate, it is only necessary to completely bury the arch beam in the concrete to a certain thickness, which can reduce the thickness of the second-phase concrete on both sides and achieve the goal of greatly reducing the amount of concrete materials. The anchor rod is equipped with an anchor beam, which acts on the first-phase concrete to anchor the arch beam or prestressed steel beam in the first-phase concrete and the foundation rock and soil, solving the anti-floating problem of the bottom plate as a whole.

[0021] Beneficial effect: The construction method of the underwater anti-floating and anti-cracking arch beam-bottom plate structure of the present invention can realize layered concrete pouring under non-erecting formwork conditions underwater by filling self-leveling non-dispersing concrete bags. After the strength reaches a certain value, the next layer can be poured. The quality of the multi-layer concrete is well guaranteed. It is used as a bottom plate structure and forms a concrete partition at the same time, so that a relatively limited space is formed between the partitions. In this space, conventional and cheap underwater concrete can be used for construction using the traditional conduit method, and can be poured to a reasonable height in a single time, solving the problem of erecting large side forms and removing forms underwater. The above partitions and concrete between the partitions are called first-phase concrete, and the cofferdam formed by filling concrete bags on both sides along the axial direction in the next step can solve the problem of implementing the second-phase concrete in a limited space. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the top structure of the present invention.

[0023] Figure 2 It is a schematic diagram of the main structure of the present invention.

[0024] Figure 3 It is a schematic structural diagram of a cross section of the present invention.

[0025] Figure 4 It is a schematic diagram of the structure of the enclosure in the present invention.

[0026] Figure 5 This is a schematic diagram of the vertical arrangement of the traction tubes.

[0027] Figure 6 Schematic diagram of the inclined arrangement of traction pipe intrusion.

[0028] Figure 7 This is the construction drawing of the dike.

[0029] In the figure: bottom filling bag 1; enclosure 2; cover concrete 3; anchor rod 4; anchor beam 5; steel pipe arch beam 6; pressure support 7; grouting flower pipe 9; clamp 11; base 12; connecting plate 13. DETAILED DESCRIPTION

[0030] The present invention will be further described below in conjunction with the accompanying drawings.

[0031] like Figures 1 to 7 As shown, a construction method of an underwater anti-floating and anti-cracking arch beam-bottom plate structure of the present invention comprises the following steps:

[0032] (1) Steel pipe piles for retaining soil are driven into the river banks in the underwater foundation pit area. The steel pipe piles are arranged in double rows and concrete is poured into the double rows of steel pipe piles to form anti-sliding support for the bank slope;

[0033] (2) According to the design requirements, large slope reduction and silt removal are carried out at the embankment between the two rows of steel pipe piles. After the layout, the bottom filling bags are laid on the embankment, and the bottom leveling layer concrete is poured. The thickness of the bottom filling bags is 30-50cm, and the elevation difference of the top surface of the filling bags is controlled within 10cm. After the strength reaches 80%, the next layer of concrete bags is filled. The height of the embankment is the bottom surface height of the second phase concrete of the top plate. After the bottom leveling layer concrete is poured, the bottom filling bags can be laid on both sides to form a cavity in the middle, and the cover plate concrete is poured in the cavity 3, as shown in FIG. Figure 7 As shown;

[0034] (3) All dikes are filled in sequence. After two dikes are completed, the area between the two dikes is desilted and acceptance is conducted after the base surface is basically reached;

[0035] (4) After the arch beam is manufactured, it is floated to the designated location in a suspended state. The arch beam arch foot has anchor plates and anchor beams to ensure stability in the water. After it is in place, hollow precast concrete is used to level the part. A certain amount of cement-based grouting material is added to the pipe to enhance its stability. Grouting holes are provided on the upper part of the steel pipe arch beam.

[0036] (5) Enclosures are provided on both sides of the steel tube arch beam, and the enclosures on both sides are connected by underwater 0 deadweight transverse pressure support 7. The pressure can be hydraulic pressure, air pressure, water pressure or oil pressure, such as Figure 4As shown, the C20 concrete 300cm or self-leveling underwater non-dispersible concrete is poured using the conduit method. The enclosure includes traction pipes stacked from bottom to top, and the traction pipe includes a main pipe located in the center and a grouting flower pipe arranged circumferentially around the main pipe. The grouting flower pipe is covered with a base, and the main pipe is covered with a clamp. The clamp is connected to the base through a connecting plate, and the connecting plate is hinged to the clamp and the base respectively; according to the traction pipe process, a pilot hole is first directional drilled according to the design route by a drilling rig, and then the hole is pulled back to expand the hole diameter to meet the caliber required for laying the traction main pipe and the grouting flower pipe, and the main pipe and the grouting flower pipe are fixed to the traction head, and the pipe is pulled back; the main pipe is butt-jointed by a hot melt process, and the grouting flower pipe is butt-jointed by a threaded sleeve, and the main pipe and the steel flower pipe are clamped and hinged; after the pull-back is in place, the traction equipment is removed to ensure that the main pipe does not move, and the steel flower pipe is pulled and stretched to rotate the connection hinge and open the grouting flower pipe.

[0037] (6) Ordinary underwater concrete construction is carried out between the two dikes, and grouting pipes are reserved at the interface with the dike and the bottom to bury the arch beam intactly in the first phase concrete;

[0038] (7) Anchor rods are provided at the roots of both sides of the steel tube arch beam, and the anchor rods pass through the poured concrete;

[0039] (8) A transverse prestressed steel beam is arranged on the poured concrete, and the transverse prestressed steel beam is fixed on the anchor rod;

[0040] (9) Pour low-heat C30 concrete on the concrete until it meets the design requirements.

[0041] In the present invention, the typical section process of the riverbed is as follows: first, anti-scouring and retaining steel sheet piles are constructed, the steel sheet piles are buried no less than 4m from the existing riverbed, and each 20m is a unit, and the steel sheet piles above the design elevation are cut off; silt and fine sand are cleaned according to the designed excavation line, and suction dredgers and dredgers are used in combination; segmented excavation and cleaning are carried out and acceptance is carried out, and underwater concrete construction of a 20cm thick cushion layer is implemented; the first phase C20 concrete step method is used for construction, with a thickness of 300cm, and the first and second phases are constructed according to the design requirements respectively, which are determined by the design; anchor rod construction, including drilling, anchor rod cutting, anchor rod lowering, high-strength anchor material pouring, anchor installation, and prestressing; transverse prestressed steel beams are processed and put in place; second phase low-heat C30 and C20 concrete pouring.

[0042] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A construction method for an underwater anti-floating and anti-cracking arch beam-bottom plate structure, characterized in that: The following steps are involved: (1) Steel pipe piles for retaining soil are driven into the river banks in the underwater foundation pit area. The steel pipe piles are arranged in double rows and concrete is poured into the double rows of steel pipe piles to form anti-sliding support for the bank slope; (2) According to the design requirements, large slope reduction and silt removal are carried out at the embankment between the two rows of steel pipe piles. After the layout, the bottom filling bags are laid on the embankment, and the bottom leveling layer concrete is poured. The thickness of the bottom filling bags is 30-50cm. After the strength reaches 80%, the next layer of concrete bags is filled. The height of the embankment is the bottom surface height of the second phase concrete of the top plate; (3) All dikes are filled in sequence. After two dikes are completed, the area between the two dikes is desilted and acceptance is conducted after the base surface is basically reached; (4) After the arch beam is manufactured, it is floated to the designated location in a suspended state. The arch beam has an anchor plate and an anchor beam at the arch foot. After it is in place, hollow precast concrete is used to level the part. A certain amount of cement-based grouting material is added to the pipe. Grouting holes are provided on the upper part of the steel pipe arch beam. (5) Set up enclosures at both ends of the steel tube arch beam; (6) Ordinary underwater concrete construction is carried out between the two dikes, and grouting pipes are reserved at the interface with the dike and the bottom to bury the arch beam intactly in the first phase concrete; (7) Anchor rods are provided at the roots of both ends of the steel tube arch beam, and the anchor rods pass through the poured concrete; (8) A transverse prestressed steel beam is arranged on the poured concrete, and the transverse prestressed steel beam is fixed on the anchor rod; (9) Pour low-heat C30 concrete on the concrete until it meets the design requirements.

2. The construction method of the underwater anti-floating and anti-cracking arch beam-bottom plate structure according to claim 1 is characterized in that: The enclosure includes traction pipes stacked from bottom to top, and the traction pipes include a main pipe located in the center and grouting pipes arranged circumferentially around the main pipe. The grouting pipes are covered with a base, and the main pipe is covered with a clamp. The clamp is connected to the base through a connecting plate, and the connecting plate is hinged to the clamp and the base respectively.

3. The construction method of the underwater anti-floating and anti-cracking arch beam-bottom plate structure according to claim 2 is characterized in that: According to the traction pipe process, first use a drilling rig to directional drill a pilot hole according to the designed route, and then pull back to expand the hole diameter to a diameter that meets the requirements of laying the traction main pipe and grouting pipe, fix the main pipe and grouting pipe to the traction head, and pull back the pipe; the main pipe is connected by hot melt technology, the grouting pipe is connected by threaded sleeves, and the main pipe and steel pipe are connected by clamps and hinges; after pulling back into place, remove the traction equipment to ensure that the main pipe does not move, pull and stretch the steel pipe, rotate the connecting hinge, and open the grouting pipe.

4. The construction method of the underwater anti-floating and anti-cracking arch beam-bottom plate structure according to claim 1 is characterized in that: After the bottom leveling layer concrete is poured in step (2), bottom filling bags are continuously arranged on both sides to form a cavity in the middle, and the cover plate concrete is poured in the cavity.

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