A construction method for single-sided formwork reinforcement of deep foundation pits

Abstract

This invention discloses a construction method for single-sided formwork reinforcement of deep foundation pits, relating to the field of building construction technology, including the following steps: S10, Structural base slab construction: measuring and setting out lines and controlling the position, installing the structural base slab and pre-embedding the reinforcing bars into the slab; S20, scaffolding construction; S30, Outer formwork construction: first installing the outer formwork, then drilling holes in the formwork, and installing rebar along the holes, injecting chemical adhesive during rebar installation, and laying the outer wall brick formwork after the required strength is achieved; S40, Waterproofing and its protective layer construction, and waterproofing joint treatment; S50, Inner formwork construction; S60, Wall and column concrete pouring: adopting a layer-by-layer slab wall pouring method, the pouring sequence must be as follows: first pour the inner walls and frame columns to the bottom of the beams, then pour the outer walls in layers, and finally pour the top slab. The beneficial effects of this invention are: ensuring the accuracy and stability of the construction method.

Description

Technical Field

[0001] This invention relates to the field of building construction technology, and more specifically, to a construction method for single-sided formwork reinforcement of deep foundation pits. Background Technology

[0002] Basement construction is an important measure to expand building land space. For some construction projects located in bustling urban areas, due to the influence of surrounding buildings and structures, only single-sided formwork construction technology can be used for basement exterior wall construction. However, this construction technology has certain difficulties in formwork processing and installation, and often has problems such as weak formwork integrity, grout leakage, and positioning difficulties. Summary of the Invention

[0003] To overcome the shortcomings of existing technologies, this invention provides a construction method for single-sided formwork reinforcement of deep foundation pits, which solves the problems of weak formwork integrity, grout leakage, and positioning difficulties in current construction methods, and ensures the accuracy and stability of the construction method.

[0004] The technical solution adopted by this invention to solve its technical problem is: a construction method for single-sided formwork reinforcement of deep foundation pits, the improvement of which is that the method includes the following steps:

[0005] S10, Structural base slab construction: Measure and set out the lines and control the position, install the structural base slab and pre-embed the reinforcing bars into the slab;

[0006] S20, Scaffolding construction: Scaffolding includes uprights, horizontal bars, scissor braces, and components; first, fix the uprights vertically to the base plate in an array; then fix the horizontal bars horizontally between the uprights; then support the scissor braces between the horizontal bars and fix them to the base plate; finally, fix the components to the uprights and horizontal bars.

[0007] S30, outer formwork construction: First, install the outer formwork, then drill holes in the formwork and install bolts along the holes. When installing the bolts, fill the formwork with chemical adhesive. After the strength reaches the required level, the outer wall brick formwork is then laid.

[0008] S40, waterproofing and its protective layer construction, waterproofing joint treatment;

[0009] S50, inner side formwork construction, specifically includes:

[0010] S501, Inner Formwork Installation: After the inner formwork of the wall is assembled on site, first measure the actual bolt spacing on site, then mark the horizontal and vertical lines on the formwork surface according to the measured spacing, and drill bolt holes. Finally, use U-shaped clamps to clamp the vertically distributed steel channels on the formwork surface and lock them with double nuts.

[0011] S502, Formwork System Reinforcement: The wall formwork reinforcement system uses three diagonal braces (top, middle, and bottom) and locking channel steel to fix the entire formwork system. The bottom of the formwork is locked by vertical channel steel, locking channel steel, and pre-embedded steel bars in the base plate. Where there is a slight misalignment of the pre-embedded steel bars, wooden wedges are used to tighten them.

[0012] S60, Concrete pouring for walls and columns: The method of pouring the wall slab layer by layer is adopted. The pouring sequence must be as follows: first pour the inner walls and frame columns up to the bottom of the beam, then pour the outer walls in layers, and finally pour the top slab.

[0013] Furthermore, in step S20, the longitudinal distance between the uprights is 1-2m, the transverse distance is 0.8-1.2m, and the distance between the inner uprights and the brick formwork is 0.2-0.4m.

[0014] Furthermore, in step S20, the horizontal bar includes a large horizontal bar, a small horizontal bar, and a sweeping bar. The large horizontal bar has a step distance of 1.5m, the small horizontal bar has a spacing of 1-2m, the sweeping bar is 0.1-0.3m from the ground, the large horizontal bar has a horizontal spacing of 0.8-1.2m, a filling bar is set in the center, and the small horizontal bar is located on the upper side of the large horizontal bar.

[0015] Furthermore, in step S20, the scissor bracing is composed of horizontal diagonal bars in a zigzag pattern from the bottom to the top; the diagonal bars are installed by overlapping or butt joints, with a length of not less than 1m, and the inclination angle between the diagonal bars and the bottom surface is between 45° and 60°, and they are fastened with three fasteners; the diagonal bars are fixed to the extended end of the intersecting horizontal bar or the upright with swivel fasteners, and the distance from the center line of the swivel fastener to the main node is not greater than 150mm.

[0016] Furthermore, in step S20, the components include scaffold boards, dense mesh netting, horizontal wide-mesh netting, and toe boards; the scaffold boards are installed every other layer, fully covering the entire area, with a distance of no more than 0.15m from the outer wall, and are fixed to the horizontal poles with wire; the dense mesh netting is installed on the inside of the uprights and fixed to the uprights or horizontal poles with wire; the horizontal wide-mesh netting is installed every 8-10m and fixed to the uprights or horizontal poles with wire; the toe boards are made of high-strength plywood, installed on the working layer, running along the inner side of the outer uprights, and fixed with wire.

[0017] Furthermore, the brick formwork is constructed using cement bricks and cement mortar, and then filled with concrete. The brick formwork is constructed according to masonry specifications, with buttress columns installed every 4-5 meters. When the brick formwork height exceeds 4 meters, a reinforced concrete capping beam is installed.

[0018] Furthermore, in step S40, the specific method for constructing the waterproofing and its protective layer includes the following steps:

[0019] S401, the lower 0.6-0.8m height of the brick formwork area of ​​the base slab is covered with self-adhesive polymer modified bitumen waterproof membrane, and the above area is covered with polyurethane waterproof membrane. After the membrane rises 0.1-0.3m from the bottom of the beam, it is sealed with polyurethane. At this time, the polyurethane waterproof layer of the exterior wall brick formwork overlaps with the waterproof membrane by 0.1-0.3m.

[0020] S402, an additional layer of waterproof membrane reinforcement is added to the polyurethane waterproof membrane at the interface with the waterproof membrane, with an overlap of not less than 200mm on each side;

[0021] S403, apply an additional layer of polyurethane waterproof coating to the additional waterproof membrane, with the polyurethane waterproof coating overlapping the additional layer of waterproof membrane and the original polyurethane waterproof layer by no less than 200mm.

[0022] Furthermore, the specific method for handling the waterproof joint is as follows: In step S30, the screw passing through the waterproof part needs to be reinforced. After the waterproof membrane is applied, a thick layer of polyurethane waterproof coating is applied to the waterproof membrane within 50mm of the screw root. For loose pre-embedded screws, after extraction, an epoxy resin is applied and the screw is re-inserted into the brick formwork. The screw is equipped with a water-stop plate, a positioning steel bar clip, and a plastic cup plug. The water-stop plate is located on both sides of the brick formwork. The positioning steel bar clip is close to the brick formwork and the channel steel. The plastic cup plug is close to the positioning steel bar clip.

[0023] Furthermore, in single-sided formwork structures, the parts with brick masonry formwork are waterproofed using the method described in step S40; in parts without brick masonry formwork, mesh is directly applied to the retaining wall, followed by plastering with cement mortar, and then waterproofing is applied after the base layer is completed.

[0024] Furthermore, in step S60, concrete vibration is required during pouring. The specific operation method is as follows: the exterior wall concrete is vibrated in a quincunx pattern with a vibrator. The vibration time is based on the concrete surface no longer sinking significantly and no more air bubbles appearing, which is generally 10-20 seconds. When vibrating the upper layer of concrete, the vibrator should be inserted into the lower layer of concrete to ensure that the layers of concrete are tightly bonded.

[0025] The beneficial effects of this invention are: by pre-embedding steel bars in the structural base slab and fixing the outer formwork with bolts, displacement and deformation of the structural base slab and outer formwork during the pouring process are prevented; and by waterproofing and its protective layer construction and waterproof joint treatment, the occurrence of grout leakage in the building structure is avoided, thereby ensuring the accuracy and stability of the construction method. Attached Figure Description

[0026] Figure 1 This is a flowchart illustrating a construction method for single-sided formwork reinforcement of deep foundation pits according to the present invention.

[0027] Figure 2This is a schematic diagram of the construction structure of a construction method for single-sided formwork reinforcement of deep foundation pits according to the present invention. Figure 1 ;

[0028] Figure 3 This is a schematic diagram of the construction structure of a construction method for single-sided formwork reinforcement of deep foundation pits according to the present invention. Figure 2 ;

[0029] Figure 4 This is a schematic diagram of a waterproof joint structure in a construction method for single-sided formwork reinforcement of deep foundation pits according to the present invention.

[0030] Figure 5 This is a schematic diagram of the construction structure of a construction method for single-sided formwork reinforcement of deep foundation pits according to the present invention. Figure 3 . Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0032] The following will clearly and completely describe the concept, specific structure, and technical effects of the present invention in conjunction with embodiments and accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention. Furthermore, all connections / linkages involved in the patent do not simply refer to direct contact between components, but rather to the ability to form a better connection structure by adding or reducing connecting accessories according to specific implementation conditions. The various technical features in this invention can be combined interactively without contradicting each other.

[0033] Reference Figure 1-5 As shown, this invention discloses a construction method for single-sided formwork reinforcement of deep foundation pits, the method comprising the following steps:

[0034] S10, Construction of Structural Base Slab 6: Measure and lay out the lines to control the position, install the structural base slab 61 and embed the reinforcing bars into the slab to fix it and prevent deformation and displacement during subsequent concrete pouring. Specifically, a row of Φ16 reinforcing bars is embedded 300-400mm from the inner side of the basement exterior wall 3 to prevent the formwork from floating. The embedded reinforcing bars 5 are spaced 1500mm apart along the wall direction. A row of Φ25 short reinforcing bars is embedded at positions 2000mm, 3000mm, and 4000mm from the inner side of the basement exterior wall 3, with a spacing of 1500mm along the wall. This ensures the stability and accuracy of the construction method.

[0035] S20, Scaffolding construction: The scaffolding includes uprights 7, horizontal bars 8, scissor braces, and components; first, the uprights 7 are vertically fixed in an array to the base plate 6; then, the horizontal bars 8 are horizontally fixed between the uprights 7; then, the scissor braces are supported between the horizontal bars 8 and fixed to the base plate 6; finally, the components are fixedly installed on the uprights 7 and horizontal bars 8; wherein: the longitudinal spacing between the uprights 7 is 1.5m, the transverse spacing is 1m, and the distance between the inner uprights 7 and the brick formwork is 20.3m;

[0036] The horizontal bar 8 includes a main horizontal bar 13, a secondary horizontal bar 14, and a sweeping bar 15. The main horizontal bar 13 has a step distance of 1.5m, the secondary horizontal bar 14 has a spacing of 1.5m, the sweeping bar 15 is 0.2m from the ground, the main horizontal bar 13 has a horizontal spacing of 1m, and a core-filling bar is set in the center. The secondary horizontal bar 14 is located on the upper side of the main horizontal bar 13. The scissor bracing is composed of horizontal diagonal bars 9 in a zigzag shape from the bottom layer to the top layer. The diagonal bars 9 are steel pipes with a diameter of Φ48.3×3.6.

[0037] The diagonal brace 9 is installed by overlapping or butt joint, with a length of not less than 1m. The inclination angle between the diagonal brace 9 and the bottom surface is between 45° and 60°, and it is fastened with three fasteners. The diagonal brace 9 is fixed to the extended end of the horizontal bar 8 or the vertical bar 7 that intersects it with a swivel fastener. The distance from the center line of the swivel fastener to the main node is not greater than 150mm.

[0038] In this embodiment, the uprights 7 and horizontal bars 8 are made of Φ48.3×3.6 steel pipes. The scaffolding is erected before the construction of the brick formwork 2 and dismantled after the construction of the brick formwork 2.

[0039] The components include scaffold boards, dense mesh netting, horizontal wide-mesh netting, and toe boards. Scaffold boards are installed every other layer, fully covering the surface, with a distance of no more than 0.15m from the outer wall 3, and are secured to the horizontal poles 8 with wire. The dense mesh netting is installed inside the uprights 7 and secured to the uprights 7 or horizontal poles 8 with wire. The horizontal wide-mesh netting is installed every 9m and secured to the uprights 7 or horizontal poles 8 with wire. The toe boards are made of 200mm high plywood, installed on the working layer, running the length of the inner side of the outer uprights 7, and secured with wire.

[0040] S30, External Formwork Construction: First, install the external formwork, then drill holes in the formwork and install bolts along the holes, filling the holes with chemical adhesive during the installation. After the required strength is achieved, construct the external wall 3-brick formwork 2. The brick formwork 2 is constructed using cement bricks and cement mortar, and then filled with concrete. The brick formwork 2 is constructed according to masonry specifications, with 240×300mm buttress columns installed every 4500mm. When the brick formwork 2 is constructed to a height exceeding 4m, a 240×300mm reinforced concrete capping beam is installed. The bolt installation is to prevent deformation and displacement of the external formwork during concrete pouring, thereby further ensuring the stability and accuracy of the construction method.

[0041] In this embodiment, before constructing the brick formwork 2, the slope is trimmed and loose stones and mud are removed; the thickness of both horizontal and vertical mortar joints is controlled to be around 10mm; the verticality deviation is ≤10mm and the flatness is ≤5mm; after the masonry is completed and the concrete is poured, plastering is carried out on the brick formwork on the side of the basement exterior wall 3; the plastering thickness is 20mm; the verticality deviation is ≤8mm and the flatness is ≤5mm; among them, special attention should be paid to the verticality and flatness during the construction of the brick formwork. Waterproofing and its protective layer construction are also required on the outside of the brick formwork, so the verticality and flatness requirements of the brick formwork are high; during the construction process, the verticality and flatness should be checked at any time with a plumb line; the bolts 1 passing through the brick formwork should be reserved strictly according to their design spacing, and it is strictly forbidden to bend the bolts 1 for the convenience of masonry construction.

[0042] S40, Waterproofing and its protective layer construction, waterproof joint treatment; the specific method of waterproofing and its protective layer construction includes the following steps:

[0043] S401, the bottom slab 6 is made of brick formwork 2. The lower 700mm section is covered with self-adhesive polymer modified bitumen waterproof membrane. The above section is covered with 2mm polyurethane waterproof membrane. After the membrane rises 200mm from the bottom of the beam, it is sealed with polyurethane. At this time, the polyurethane waterproof layer of the brick formwork 2 on the exterior wall 3 overlaps with the waterproof membrane by 200mm.

[0044] S402, an additional layer of waterproof membrane reinforcement is added to the polyurethane waterproof membrane at the interface with the waterproof membrane, with an overlap of not less than 200mm on each side;

[0045] S403, apply an additional layer of polyurethane waterproof coating to the additional waterproof membrane, with the polyurethane waterproof coating overlapping the additional layer of waterproof membrane and the original polyurethane waterproof layer by no less than 200mm.

[0046] The specific method for handling the waterproof joint is as follows: In step S30, the screw 1 passing through the waterproof part needs to be reinforced. After the waterproof membrane is applied, a 1.5mm thick layer of polyurethane waterproof coating is applied to the waterproof membrane within a 50mm range above the root of the screw 1. For the pre-embedded loose screw 1, after it is pulled out, an epoxy resin is applied and it is re-inserted into the brick formwork 2. The screw 1 is equipped with a water-stop plate 10, a positioning steel bar clip 11, and a plastic cup plug 12. The water-stop plate 10 is located on both sides of the brick formwork 2. The positioning steel bar clip 11 is close to the brick formwork and the channel steel 4. The plastic cup plug 12 is close to the positioning steel bar clip 11. After the concrete is poured, the plastic cup plug of the screw 1 is removed, a small groove is chiseled, and the groove is filled with a leak-proof solution.

[0047] In addition, for the parts of the single-sided formwork structure with brick formwork 2, waterproofing is carried out in step S40; for the parts without brick formwork 2, the mesh is directly hung on the retaining wall and plaster is applied, using Φ4@200×200 mesh and 1:2 cement mortar plaster, and the waterproofing coating is applied after the base layer is completed.

[0048] S50, inner side formwork construction, specifically includes:

[0049] S501, Inner Formwork Installation: After the inner formwork of the wall is assembled on site, first measure the actual spacing of the screw rods 1 on site, then mark the horizontal and vertical lines on the surface of the formwork according to the measured spacing, and drill 1 hole for the screw rods. Finally, use the U-shaped clamps to clamp the vertically distributed steel channels on the surface of the formwork and lock them with double nuts.

[0050] S502, Formwork system reinforcement: The wall formwork reinforcement system uses three diagonal braces (top, middle, and bottom) and locking channel steel 4 to fix the entire formwork system. The bottom of the formwork is locked by the vertical channel steel 4, locking channel steel 4, and the steel bars embedded in the bottom plate 6. If there is a slight misalignment of the embedded steel bars 5 in some areas, wooden wedges are used to tighten them.

[0051] S60, Wall and Column Concrete Pouring: A layer-by-layer integral pouring method is adopted. The pouring sequence must be as follows: first, pour the inner walls and frame columns up to the bottom of the beams; then, pour the outer walls in three layers; finally, pour the top slab. The three-layer pouring of the outer walls must be done in sections according to the location of the post-pouring strip; the layer thickness should not exceed 1.0m, and the upper layer of concrete should be poured before the initial setting of the lower layer. Concrete vibration is required during pouring. The specific operation method is as follows: Use a Φ50 vibrator in a staggered pattern to vibrate the outer wall concrete in a staggered pattern. The vibration time is until the concrete surface no longer significantly sinks or bubbles appear, generally around 15 seconds. When vibrating the upper layer of concrete, the vibrator should be inserted approximately 50mm into the lower layer of concrete to ensure tight bonding between the layers.

[0052] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A construction method for single-sided formwork reinforcement of deep foundation pits, characterized in that, The method includes the following steps: S10, Structural base slab construction: Measure and set out the lines and control the position, install the structural base slab and pre-embed the reinforcing bars into the slab; S20, Scaffolding Construction: Scaffolding includes uprights, horizontal bars, scissor bracing, and components. First, the uprights are vertically fixed to the base plate in an array. Then, the horizontal bars are horizontally fixed between the uprights. Next, the scissor bracing is supported between the horizontal bars and fixed to the base plate. Finally, the components are fixedly installed on the uprights and horizontal bars. The horizontal bars include main horizontal bars, secondary horizontal bars, and ground-level bars. The main horizontal bar spacing is 1.5m, the secondary horizontal bar spacing is 1-2m, the ground-level bars are 0.1-0.3m from the ground, the main horizontal bar spacing is 0.8-1.2m, and a core-filling rod is placed in the center. The small horizontal bar is located on the upper side of the large horizontal bar; the longitudinal spacing between the uprights is 1-2m, the transverse spacing is 0.8-1.2m, and the distance between the inner uprights and the brick formwork is 0.2-0.4m; the scissor bracing is composed of zigzag horizontal diagonal bars from the bottom layer to the top layer; the diagonal bars are installed by overlapping or butt joints, with a length of not less than 1m, and the inclination angle between the diagonal bars and the bottom surface is between 45° and 60°, and they are fastened with three fasteners; the diagonal bars are fixed to the extended end of the intersecting horizontal bar or the upright with swivel fasteners, and the distance from the center line of the swivel fastener to the main node is not greater than 150mm; S30, outer formwork construction: First, install the outer formwork, then drill holes in the formwork and install bolts along the holes. When installing the bolts, fill the formwork with chemical adhesive. After the strength reaches the required level, the outer wall brick formwork is then laid. S40, Waterproofing and its protective layer construction, and waterproof joint treatment; wherein, the specific method of waterproofing and its protective layer construction includes the following steps: S401, the lower 0.6-0.8m height of the brick formwork area of ​​the base slab is covered with self-adhesive polymer modified bitumen waterproof membrane, and the above area is covered with polyurethane waterproof membrane. After the membrane rises 0.1-0.3m from the bottom of the beam, it is sealed with polyurethane. At this time, the polyurethane waterproof layer of the exterior wall brick formwork overlaps with the waterproof membrane by 0.1-0.3m. S402, an additional layer of waterproof membrane reinforcement is added to the polyurethane waterproof membrane at the interface with the waterproof membrane, with an overlap of not less than 200mm on each side; S403, apply an additional layer of polyurethane waterproof coating on the additional waterproof membrane, with the polyurethane waterproof coating overlapping the additional layer of waterproof membrane and the original polyurethane waterproof layer by no less than 200mm. S50, inner side formwork construction, specifically includes: S501, Inner Formwork Installation: After the inner formwork of the wall is assembled on site, first measure the actual bolt spacing on site, then mark the horizontal and vertical lines on the formwork surface according to the measured spacing, and drill bolt holes. Finally, use U-shaped clamps to clamp the vertically distributed steel channels on the formwork surface and lock them with double nuts. S502, Formwork System Reinforcement: The wall formwork reinforcement system uses three diagonal braces (top, middle, and bottom) and locking channel steel to fix the entire formwork system. The bottom of the formwork is locked by vertical channel steel, locking channel steel, and pre-embedded steel bars in the base plate. Where there is a slight misalignment of the pre-embedded steel bars, wooden wedges are used to tighten them. S60, Concrete pouring for walls and columns: The method of pouring the walls layer by layer is adopted. The pouring sequence must be as follows: first pour the inner walls and frame columns up to the bottom of the beams, then pour the outer walls in layers, and finally pour the top slab. During the pouring, concrete vibration is required. The specific operation method is as follows: the outer wall concrete is vibrated with a vibrator in a quincunx pattern. The vibration time is until the concrete surface no longer sinks significantly and no more air bubbles appear. The time is generally 10-20 seconds. When vibrating the upper layer of concrete, the vibrator should be inserted into the lower layer of concrete to make the layers of concrete tightly bonded.

2. The construction method for single-sided formwork reinforcement of deep foundation pits according to claim 1, characterized in that, In step S20, the components include scaffold boards, dense mesh netting, horizontal wide-mesh netting, and toe boards; the scaffold boards are installed every other layer, fully covering the entire area, with a distance of no more than 0.15m from the outer wall, and are fixed to the horizontal poles with wire; the dense mesh netting is installed on the inside of the uprights and fixed to the uprights or horizontal poles with wire; the horizontal wide-mesh netting is installed every 8-10m and fixed to the uprights or horizontal poles with wire; the toe boards are made of high-strength plywood, installed on the working layer, running along the inner side of the outer uprights, and fixed with wire.

3. The construction method for single-sided formwork reinforcement of deep foundation pits according to claim 1, characterized in that, The brick formwork is constructed using cement bricks and cement mortar, and then filled with concrete. The brick formwork is constructed according to masonry specifications, with buttress columns installed every 4-5 meters. When the brick formwork height exceeds 4 meters, a reinforced concrete capping beam is installed.

4. The construction method for single-sided formwork reinforcement of deep foundation pits according to claim 1, characterized in that, The specific method for handling the waterproof joint is as follows: In step S30, the screw passing through the waterproof part needs to be reinforced. After the waterproof membrane is applied, a thick layer of polyurethane waterproof coating is applied to the waterproof membrane within 50mm of the screw root. For loose pre-embedded screws, after extraction, an epoxy resin is applied and the screws are re-inserted into the brick formwork. The screw is equipped with a water-stop plate, a positioning steel bar clip, and a plastic cup plug. The water-stop plate is located on both sides of the brick formwork. The positioning steel bar clip is close to the brick formwork and the channel steel. The plastic cup plug is close to the positioning steel bar clip.

5. The construction method for single-sided formwork reinforcement of deep foundation pits according to claim 1, characterized in that, For single-sided formwork structures with brick-built formwork, waterproofing is carried out using the method described in step S40; for areas without brick-built formwork, mesh is directly applied to the retaining wall, followed by plastering with cement mortar, and then waterproofing is applied after the base layer is completed.

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