A construction shaft assembly type mold box construction system and method

Abstract

The application discloses a building shaft assembly type mold box construction system and method, which comprises a shaft bottom mold system, a shaft wall mold system, a heavy pressure support system and a stress monitoring system. The shaft bottom mold system comprises a bottom mold assembly and a guide positioning assembly on the bottom mold assembly. The shaft wall mold system comprises a wall corner mold, a wall middle mold, a mold plate locking vertical plate assembly and a reinforced fixed top plate. Four wall middle molds are placed in a quadrilateral shape, and a group of wall corner molds are arranged between adjacent wall middle molds. The upper end of the wall corner mold is connected with the wall middle mold through the reinforced fixed top plate. The inner end of the wall corner mold is provided with a first locking support plate, and the inner end of the end of the wall middle mold is provided with a second locking support plate. The first locking support plate is connected with the second locking support plate through the mold plate locking vertical plate assembly. The heavy pressure support system comprises an inner support mechanism arranged in the wall middle mold and a heavy pressure assembly arranged at the upper end of the inner support mechanism. The mold box has a simple and novel structure, is suitable for turnover use of multiple construction flow sections, has a safe and reliable dismounting method and good turnover efficiency.

Description

Technical Field

[0001] This invention relates to the field of building construction technology, specifically to a prefabricated modular construction system and method for building pits. Background Technology

[0002] In construction engineering, the main materials used for pit formwork include metal formwork (steel formwork, aluminum formwork), wooden formwork (bamboo plywood, composite formwork), and plastic formwork, etc. Correspondingly, commonly used construction methods include standardized formwork construction, piece-by-piece dismantling, and prefabricated piece-by-piece dismantling, etc. Currently, the main problems in the construction technology of formwork for cast-in-place pit structures are:

[0003] 1. The prefabricated template process using materials such as metal, wood or plastic is manufactured in the factory. It is compatible with the pit and has suitable application. It has high construction efficiency and guaranteed quality. However, due to the high cost, it is not universally applicable except under special requirements.

[0004] 2. Using combined steel molds, aluminum molds, wooden molds, etc., designed and fabricated according to the size of the well pit, and then carrying out the construction on site in a piecemeal manner, this working condition is not suitable for repeated construction in multiple sections; moreover, the long-term on-site operation leads to high safety risks, low efficiency, and high labor consumption.

[0005] 3. Construction using wooden formwork is characterized by its light weight, ease of processing, and low cost, and is currently more widely used than metal formwork. Most of this method employs a modular assembly and disassembly approach, where wooden formwork boxes are fabricated simultaneously in a processing plant while the reinforcing steel is being tied on-site. These boxes are then hoisted using equipment such as tower cranes, and after the concrete has been poured and reached a certain strength, the formwork is dismantled piece by piece. This method has advantages over the modular assembly and disassembly approach, offering the benefits of convenient overall hoisting and installation. However, because the subsequent disassembly process is done piece by piece, it hinders the smooth and rapid organization of continuous construction, resulting in a lower overall turnover rate and reduced efficiency. Summary of the Invention

[0006] The purpose of this invention is to provide a prefabricated formwork construction system for building pits. By considering the entire construction process, it adopts readily available and commonly used construction templates to form a prefabricated formwork structure that is easy to process, hoist, install, and dismantle. It is suitable for multiple construction flow sections and can reduce safety risks and improve the quality of pit concrete forming. At the same time, it promotes green and environmentally friendly construction, saves materials and reduces consumption, lowers costs, and improves work efficiency.

[0007] To achieve the above objectives, the technical solution adopted by this invention is as follows:

[0008] A prefabricated formwork construction system for building pits, characterized in that it includes a pit bottom formwork system, a pit wall formwork system, a counterweight support system and a stress monitoring system. The pit bottom formwork system includes a bottom formwork component and a guide and positioning component on the bottom formwork component. The bottom formwork component is provided with vent holes.

[0009] The pit wall formwork system includes corner formwork, middle formwork, template locking vertical plate assembly and reinforcing fixed top plate. The four middle formworks are placed in a quadrilateral shape, and a set of corner formworks is set between adjacent middle formworks. The upper end of the corner formwork is connected to the middle formwork through the reinforcing fixed top plate.

[0010] The inner end of the corner mold is provided with a first locking support plate, and the inner end of the middle mold is provided with a second locking support plate. The first locking support plate is connected to the second locking support plate through the template locking vertical plate assembly.

[0011] The counterweight support system includes an internal support mechanism installed inside the wall formwork and a counterweight assembly installed at the upper end of the internal support mechanism. The internal support mechanism includes an internal support frame, a back brace frame, and an internal support bracket fastener. The counterweight assembly is connected to the upper end of the internal support frame and the pit wall formwork system.

[0012] The force monitoring system includes a central monitoring controller and a sensor support mechanism. The sensor support mechanism is connected to the side end of the inner support frame. The sensor support mechanism includes a first force support plate, a second force support plate, and multiple electro-hydraulic support columns disposed between the first force support plate and the second force support plate. The outer end of the second force support plate is connected to a snap-on support shaft.

[0013] The upper end of the inner support frame and the buckle support shaft are both connected to the inner support bracket buckle; the back rib frame is located around the inner support frame and is pressed onto the inner end face of the wall mold through the inner support bracket buckle.

[0014] Preferably, the bottom mold assembly includes a bottom plate and a plurality of bottom ribs connected to the inner end of the bottom plate. The bottom plate is rectangular and the plurality of bottom ribs are arranged parallel to each other on the bottom plate by rivets.

[0015] The guide positioning assembly includes a central positioning block and end positioning blocks. There are four end positioning blocks, which are respectively connected to the four corners of the base plate and connected to the bottom rib.

[0016] There are multiple central positioning blocks, which are evenly distributed at the upper middle part of the base plate.

[0017] Preferably, the corner mold includes a first L-shaped support plate and a plurality of bracket ribs connected to the outer end of the first L-shaped support plate; there are a plurality of first locking support plates, and after the plurality of first locking support plates are vertically spaced, the first locking support plates are vertically connected to the first L-shaped support plate.

[0018] Preferably, there are multiple second locking support plates, and the multiple second locking support plates are arranged vertically at intervals;

[0019] The template locking vertical plate assembly includes multiple locking units, each including a locking sleeve plate and a locking bolt. Locking through holes are provided in the locking sleeve plate, the first locking support plate, and the second locking support plate.

[0020] After the locking sleeve plate is snapped onto the outer end of the first locking support plate and the outer end of the second locking support plate, it is fixed by locking bolts. At this time, the locking bolts pass through the locking through hole and are connected to the corner mold.

[0021] Preferably, the wall-mounted mold includes multiple wall-mounted vertical rods, wall-mounted horizontal rods connected to the upper and lower ends of the wall-mounted vertical rods, a first vertical plate body disposed at the front and rear ends of the wall-mounted vertical rods, and a second vertical plate body disposed at the left and right ends of the wall-mounted horizontal rods. The second vertical plate body is connected to the first L-shaped support plate through a wall-mounted fixing screw. At this time, the wall-mounted fixing screw passes through the first L-shaped support plate and is connected to the wall-mounted vertical rod.

[0022] Preferably, the reinforcing and fixing top plate is triangular in shape, and there are four reinforcing and fixing top plates. The reinforcing and fixing top plates are connected to the upper end of the first L-shaped support plate and the crossbar in the wall by rivets.

[0023] Preferably, the inner support frame includes three sets of vertical tube assemblies and three sets of planar support frames. Each set of vertical tube assemblies includes three horizontally parallel inner support vertical tubes, and the three sets of vertical tube assemblies are arranged in parallel to each other in the longitudinal direction. The three sets of planar support frames are arranged in parallel to each other in the vertical direction, and the planar support frames are connected to the inner support vertical tubes through the first tube body connector.

[0024] The planar support frame includes a set of horizontal tube assemblies and a set of vertical tube assemblies. The horizontal tube assembly includes three parallel inner support horizontal tubes, and the vertical tube assembly includes three parallel inner support vertical tubes. The inner support horizontal tubes are located at the upper end of the inner support vertical tubes, and the inner support horizontal tubes are connected to the inner support vertical tubes through a second tube body connector.

[0025] Preferably, the inner support bracket fastener includes a U-shaped snap-fit ​​plate and a support bracket connected to the U-shaped snap-fit ​​plate. The first force-bearing support plate and the second force-bearing support plate are both strip steel plates, and the first force-bearing support plate is connected to the outside of both the horizontal tube assembly and the vertical tube assembly.

[0026] A vertical support is connected to the inner support tube, and a battery pack is connected to the vertical support. The battery pack is connected to the electro-hydraulic support column via wires, and a pressure sensor is connected to the end of the electro-hydraulic support column.

[0027] Preferably, the counterweight assembly includes a counterweight support plate and a counterweight support shell connected to the counterweight support plate. A partition plate is provided inside the counterweight support shell. After the partition plate and the counterweight support shell are connected, multiple heavy object placement cavities are formed. A counterweight block or counterweight sandbag is provided in the heavy object placement cavity.

[0028] The counterweight support plate includes a counterweight plate body and a counterweight support timber connected to the lower end of the counterweight plate body. A counterweight cover is provided at the upper end of the counterweight support shell, and counterweight lifting hooks are provided at the side ends of the counterweight support shell and the side ends of the counterweight plate body.

[0029] Another objective of this invention is to provide a method for constructing prefabricated pit formwork.

[0030] To achieve the above objectives, the technical solution adopted by this invention is as follows:

[0031] A prefabricated manhole formwork construction method, employing the aforementioned prefabricated formwork construction system for building manholes, specifically includes the following:

[0032] Step 1: In the processing yard, based on the processing sample drawing, determine the quantity of wooden templates, wooden poles, steel pipes, and fasteners used in the pit bottom formwork system, pit wall formwork system, and counterweight support system. Determine the height of the corner formwork and middle formwork in the pit wall formwork system. Then process the bottom formwork assembly, corner formwork, middle formwork, template locking vertical plate assembly, and reinforced top plate, and assemble the internal support mechanism and counterweight assembly.

[0033] Step 2: In the processing yard, the bottom formwork assembly and the middle formwork need to be trial-assembled in advance. During the trial assembly, two end positioning blocks with a size of 40mm×80mm×200mm are first installed on the corner of the diagonal line inside the bottom plate. The end positioning blocks are placed flat on one side of the bottom rib, and the two end positioning blocks are tongue and groove connected to ensure that the middle formwork can be quickly and accurately aligned and positioned during hoisting. The remaining two positioning wooden blocks are added after the middle formwork is in place.

[0034] Step 3: Before installing the formwork structure of the pit, during the construction of the pit reinforcement, the construction of the supporting reinforcement under the bottom plate should be completed in between; according to the size of the pit formwork and the internal anti-buoyancy load, support points need to be reasonably set at the lower position of the pit wall formwork and the pit bottom uprights. The support points are used to support the bottom formwork components.

[0035] Step 4: Before construction, clarify the installation sequence of the well pit formwork system as follows: first, mark the positioning lines, then hoist the bottom formwork system of the well pit, then install the well pit wall formwork system, and finally hoist the counterweight support system.

[0036] Step 5: Hoist the bottom formwork assembly onto the support ribs at the bottom of the pit and ensure the stability of the support hoist; check whether the guide positioning assembly has shifted position. After confirming that there is no shift or adjusting the position, add rivets for secondary fixation.

[0037] Step Six: When hoisting the pit wall formwork system, use the formwork hoisting holes pre-drilled on the wall formwork within the pit wall formwork system. Thread steel wire ropes through the formwork hoisting holes for hoisting. Before hoisting with steel wire ropes, place a 50mm long short steel pipe inside the formwork hoisting hole. Add rubber pads to the short steel pipe to provide support and prevent damage to the hoisting hole. After installing the pit wall formwork, remove the short steel pipe and temporarily seal the hoisting hole to prevent grout leakage.

[0038] Step 7: After placing the pit wall formwork, check the position of the middle wall formwork and the corner wall formwork. Place positioning wooden blocks at the base of the wall formwork ribs around the middle wall formwork and fix them to the bottom formwork using extended screws spaced 200mm apart to prevent movement during the pouring process.

[0039] Step 8: When constructing the counterweight support system, first place the inner support frame, then install the back bracing frame around the perimeter, and then use the pipe connecting bolts to adjust and lock the snap-fit ​​position of the inner support bracket fastener. The inner support frame and support components are used to prevent buoyancy and resist the lateral pressure generated by the concrete pouring of the pit wall.

[0040] Step 9: Install the counterweight assembly onto the inner support frame and the pit wall formwork system. The load-bearing body of the counterweight assembly is the counterweight support shell. After the counterweight support shell is hoisted, place a certain amount of weight inside the counterweight support shell to prevent the pit formwork box from floating.

[0041] Step 10: Following the construction principle of removing the formwork last and removing the formwork first, the formwork should be removed when the concrete strength reaches 1.2MPa.

[0042] When dismantling the well pit formwork, first remove the counterweight components, then loosen the inner support bracket fasteners, and then lift the inner support frame as a whole and lift it out for easy transport and transfer to the next well pit flow section.

[0043] Step 11: When dismantling the formwork of the pit walls, first remove the guide positioning components at the bottom of the pit, then remove the wall formwork of the four sides of the pit, and then remove the corner formwork. The bottom formwork is dismantled piece by piece and lifted out of the pit. Clean the pit formwork box, apply release agent, hoist it to the outside of the site, and then transport it to the formwork storage area and mark the formwork serial number to prevent incorrect use order.

[0044] Step 12: When constructing a section of the project or the next construction site, repeat steps 3 through 11.

[0045] The beneficial effects of this invention are:

[0046] The pit formwork structure in this application optimizes the conventional pit bottom formwork and pit wall integrated formwork construction into a formwork construction where two large formwork panels, pit wall and pit bottom, are assembled into a formwork box. Furthermore, the pit wall formwork is divided into corner formwork and middle formwork for easy assembly and disassembly. A support frame is placed in the middle of the formwork box, thus constructing a prefabricated formwork construction system for building pits, consisting of three parts: pit bottom formwork, pit wall formwork, and counterweight support system.

[0047] Using readily available and commonly used materials, the process is simple and can be implemented on-site, eliminating the need for specialized manufacturers and significantly reducing costs. The rational and effective combination of the formwork structure allows most operations to be carried out on-site, fully utilizing lifting equipment such as tower cranes. Compared to the piecemeal method, this reduces labor requirements, saving approximately half the manpower; it also significantly reduces safety risks, making the operation safer and saving construction time by approximately 30%-50%. Considering the convenience of subsequent dismantling, reassembly, and rapid assembly, the shortcomings of the piecemeal construction method are optimized. The pit bottom and wall formwork are not fabricated as a single unit, ensuring more flexible flow of construction sections and smoother process connections. This avoids the inefficient problem of having to completely dismantle after pouring, saving construction time by approximately 20%-30%. The pit wall formwork is pre-divided into corner and middle forms, forming a large-formwork assembly process. This makes formwork construction and dismantling more convenient and facilitates secondary flow of pit wall formwork assembly. Avoiding piecemeal construction significantly reduces the formwork damage rate. The internal support frame of the mold is pre-assembled in the processing plant and can be hoisted and reused multiple times using hoisting equipment, thus improving efficiency. Attached Figure Description

[0048] Figure 1 This is a schematic diagram showing the structural locations of the pit bottom formwork system and the counterweight support system.

[0049] Figure 2 This is a schematic diagram of the internal support frame structure.

[0050] Figure 3 This is a top view of the bottom mold component structure.

[0051] Figure 4 This is a side view schematic diagram of the pit wall formwork system.

[0052] Figure 5 This is a schematic diagram of the connection structure between the corner mold and the middle mold.

[0053] Figure 6 This is a top view of the counterweight assembly.

[0054] Figure 7 This is a schematic diagram of the structural location of the sensor support mechanism.

[0055] Figure 8 This is a cross-sectional view of the central positioning block structure.

[0056] Figure 9This is a cross-sectional view of the end positioning block structure. Detailed Implementation

[0057] The present invention will now be described in detail with reference to the accompanying drawings:

[0058] Example 1, combined with Figures 1 to 9 The present invention will be described in detail below:

[0059] A prefabricated formwork construction system for building pits includes a pit bottom formwork system 1, a pit wall formwork system 2, a counterweight support system 3, and a stress monitoring system 5. The pit bottom formwork system includes a bottom formwork component 11 and a guide and positioning component 12 on the bottom formwork component 11. An exhaust hole 13 is provided inside the bottom formwork component.

[0060] The pit wall formwork system 2 includes corner formwork 21, middle formwork 22, template locking vertical plate assembly 23, and reinforcing and fixing top plate 24. The four middle formwork 22 are placed in a quadrilateral shape, and a set of corner formwork 21 is set between adjacent middle formwork 22. The upper end of the corner formwork 21 is connected to the middle formwork 22 through the reinforcing and fixing top plate 24.

[0061] The inner end of the corner mold 21 is provided with a first locking support plate 26, and the inner end of the middle mold 22 is provided with a second locking support plate 27. The first locking support plate 26 is connected to the second locking support plate 27 through the template locking vertical plate assembly 23.

[0062] The counterweight support system 3 includes an inner support mechanism 31 disposed in the wall mold 22 and a counterweight component 32 disposed on the upper end of the inner support mechanism 31. The inner support mechanism 31 includes an inner support frame 4, a back rib frame 41, and an inner support bracket fastener 42. The counterweight component 32 is connected to the inner support frame 4 and the upper end of the pit wall mold system 2.

[0063] The force monitoring system 5 includes a monitoring controller and a sensing support mechanism. The sensing support mechanism is connected to the side end of the inner support frame 4. The sensing support mechanism includes a first force support plate 51, a second force support plate 52, and a plurality of electro-hydraulic support columns 53 disposed between the first force support plate 51 and the second force support plate 52. The outer end of the second force support plate 52 is connected to a snap-on support shaft 54.

[0064] The upper end of the inner support frame 4 and the buckle support shaft 54 ​​are both connected to the inner support bracket buckle 42; the back rib frame 41 is located around the inner support frame 4 and is pressed onto the inner end face of the wall mold 22 through the inner support bracket buckle 42.

[0065] The bottom mold assembly 11 includes a bottom plate 111 and a plurality of bottom ribs 112 connected to the inner end of the bottom plate 111. The bottom plate 111 is rectangular and the plurality of bottom ribs 112 are arranged parallel to each other on the bottom plate 111 by rivets.

[0066] The guide positioning assembly 12 includes a central positioning block 121 and end positioning blocks 122. There are four end positioning blocks 122, which are respectively connected to the four corners of the base plate 111 and connected to the bottom rib 112. There are multiple central positioning blocks 121, which are evenly distributed at the upper middle part of the base plate 111.

[0067] The corner mold 21 includes a first L-shaped support plate 211 and multiple support ribs 212 connected to the outer bend of the first L-shaped support plate 211; there are multiple first locking support plates 26, and after the multiple first locking support plates 26 are vertically spaced, the first locking support plates 26 are vertically connected to the inner end of the first L-shaped support plate 211.

[0068] There are multiple second locking support plates 27, which are vertically spaced apart. The template locking vertical plate assembly 23 includes multiple locking units, each including a locking sleeve plate 231 and a locking bolt 232. Locking through holes are provided in the locking sleeve plate 231, the first locking support plate 26, and the second locking support plate 27. After the locking sleeve plate 231 is snapped onto the outer end of the first locking support plate 26 and the second locking support plate 27, it is fixed by the locking bolt 232. At this time, the locking bolt 232 passes through the locking through hole and is connected to the corner mold 2.

[0069] The wall-mounted mold 22 includes multiple wall-mounted vertical rods 221, wall-mounted horizontal rods 222 connected to the upper and lower ends of the wall-mounted vertical rods 221, a first vertical plate body set at the front and rear ends of the wall-mounted vertical rods 221, and a second vertical plate body set at the left and right ends of the wall-mounted horizontal rods 222. The second vertical plate body is connected to the first L-shaped support plate 211 through a wall-mounted fixing screw. At this time, the wall-mounted fixing screw passes through the first L-shaped support plate 211 and is connected to the wall-mounted vertical rod.

[0070] The reinforced fixed top plate 24 is triangular in shape, and the four reinforced fixed top plates 24 are distributed in a quadrilateral shape. The reinforced fixed top plates 24 are connected to the upper end of the first L-shaped support plate 211 and the wall crossbar 222 by rivets. The inner support frame 4 includes three sets of vertical pipe assemblies and three sets of planar supports. Each set of vertical pipe assemblies includes three horizontally parallel inner support vertical pipes 43. The three sets of vertical pipe assemblies are arranged vertically in parallel with each other. The three sets of planar supports are arranged vertically in parallel with each other. The planar supports are connected to the inner support vertical pipes 43 by the first pipe body connector.

[0071] The planar support frame includes a set of horizontal tube assemblies and a set of vertical tube assemblies. The horizontal tube assembly includes three parallel inner support horizontal tubes 44, and the vertical tube assembly includes three parallel inner support vertical tubes 45. The inner support horizontal tubes 44 are located at the upper end of the inner support vertical tubes 45, and the inner support horizontal tubes 44 are connected to the inner support vertical tubes 45 through a second tube body connector.

[0072] The inner support vertical tube 43, inner support longitudinal tube 45, and inner support horizontal tube 44 are all connected to inner support bracket fasteners 42; the inner support bracket fastener 42 includes a U-shaped snap plate 421 and a support tube 422 connected to the U-shaped snap plate 421. The support tube 422 is bolted to the snap support shaft 54 ​​and the inner support vertical tube 43. The snap support shaft 54 ​​and the inner support vertical tube 43 are both provided with multiple bolt-positioned holes.

[0073] The inner support bracket fastener 42 includes a U-shaped snap plate 421 and a support bracket 422 connected to the U-shaped snap plate 421. The support bracket 422 is bolted to the buckle support shaft 54 ​​and the inner support vertical tube 43. Both the buckle support shaft 54 ​​and the inner support vertical tube 43 are provided with multiple bolted positioning holes.

[0074] Both the first load-bearing support plate 51 and the second load-bearing support plate 52 are strip steel plates. The first load-bearing support plate 51 is connected to the outside of both the horizontal and vertical pipe assemblies. A vertical pipe bracket is connected to the inner support vertical pipe 43, and a battery assembly is connected to the vertical pipe bracket. The battery assembly is connected to the electro-hydraulic support column via wires, and a wireless signal transmitter and receiver are connected to the battery assembly. A pressure sensor is connected to the end of the electro-hydraulic support column. The pressure signal from the pressure sensor is transmitted to the wireless signal transmitter and receiver via wires. The wireless signal transmitter and receiver then transmits the pressure signal to the central monitoring controller to determine the deformation and safety status of the entire template. If the deformation is large or exceeds the warning value, a certain pressure is applied through the electro-hydraulic support column to prevent excessive deformation.

[0075] For the force monitoring system 5, which is an optional system, it can be decided whether to install it before construction, depending on the needs. The internal support bracket 42 can be installed on the buckle support shaft 54 ​​or on the horizontal or vertical pipe.

[0076] The counterweight assembly 32 includes a counterweight support plate 321 and a counterweight support shell 322 connected to the counterweight support plate 321. A partition plate 323 is provided inside the counterweight support shell 322. After the partition plate 323 and the counterweight support shell 322 are connected, multiple heavy object placement cavities are formed. A counterweight block or counterweight sandbag is provided in the heavy object placement cavity.

[0077] The counterweight support plate 321 includes a counterweight plate body and a counterweight support timber connected to the lower end of the counterweight plate body. The upper end of the counterweight support shell 322 is provided with a counterweight cover. Both the side end of the counterweight support shell 322 and the side end of the counterweight plate body are provided with counterweight lifting hooks.

[0078] Example 2, based on the disclosed examples, further discloses the following:

[0079] A prefabricated manhole formwork construction method, employing the prefabricated formwork construction system for building manholes described in Example 1, specifically includes the following:

[0080] Step 1: In the processing yard, based on the processing sample drawing, determine the quantity of wooden templates, timber, steel pipes, and fasteners used in the pit bottom formwork system, pit wall formwork system, and counterweight support system. Determine the height of the corner formwork and middle formwork in the pit wall formwork system. Then process the bottom formwork assembly, corner formwork, middle formwork, template locking vertical plate assembly, and reinforced top plate, and assemble the internal support mechanism and counterweight assembly.

[0081] Step 2: In the processing area, the bottom mold assembly and the middle mold of the wall need to be trial-assembled in advance. During the trial assembly, two end positioning blocks with a size of 40mm×80mm×200mm are first installed on the corner of the diagonal line inside the bottom plate. The end positioning blocks are placed flat on one side of the bottom rib, and the two end positioning blocks are tongue and groove connected to ensure that the middle mold of the wall can be quickly and accurately aligned and positioned. The remaining two positioning wooden blocks are added after the middle mold of the wall is in place.

[0082] Step 3: Before installing the formwork structure of the pit, the construction of the supporting reinforcement under the bottom slab should be completed during the construction of the pit reinforcement. According to the size of the pit formwork and the internal anti-buoyancy load, support points need to be reasonably set at the lower position of the pit wall formwork and the pit bottom uprights. The support points are used to support the bottom formwork components.

[0083] Step 4: Before construction, workers need to clarify the installation sequence of the well pit formwork system as follows: first, mark the positioning lines, then hoist the bottom formwork system of the well pit, then install the wall formwork system of the well pit, and finally hoist the counterweight support system.

[0084] Step 5: Hoist the bottom formwork assembly to the support ribs at the bottom of the pit and ensure the stability of the support hoist; check whether the guide positioning assembly has shifted position. After confirming that there is no shift or after adjusting the position, add rivets for secondary fixation.

[0085] Step Six: When hoisting the pit wall formwork system, use the formwork hoisting holes pre-drilled on the wall formwork within the pit wall formwork system. Thread steel wire ropes through the formwork hoisting holes for hoisting. Before hoisting with steel wire ropes, place a 50mm long short steel pipe inside the formwork hoisting hole. Add rubber pads to the short steel pipe to provide support and prevent damage to the hoisting hole. After installing the pit wall formwork, remove the short steel pipe and temporarily seal the hoisting hole to prevent grout leakage.

[0086] Step 7: After placing the pit wall formwork, check the position of the middle wall formwork and corner wall formwork. The positioning wooden blocks should be placed firmly against the base of the wall formwork ribs around the middle wall formwork and fixed to the bottom formwork with extended screws at 200mm intervals to prevent movement during the pouring process.

[0087] Step 8: During the construction of the counterweight support system, first place the inner support frame, then install the back bracing frame around the perimeter. Then, use the pipe connecting bolts to adjust and lock the snap-fit ​​position of the inner support bracket. The inner support frame and support components are used to prevent buoyancy and resist the lateral pressure generated by the concrete pouring of the pit wall.

[0088] Step 9: Install the counterweight assembly onto the inner support frame and the pit wall formwork system. The load-bearing body of the counterweight assembly is the counterweight support shell. After the counterweight support shell is hoisted, place a certain amount of weight inside the counterweight support shell to prevent the pit formwork box from floating.

[0089] Step 10: Following the construction principle of dismantling the formwork in the order of the first to be supported and the last to be supported, organize the dismantling of the formwork in an orderly manner, generally when the concrete strength reaches 1.2MPa.

[0090] For the dismantling of the well pit formwork, first remove the counterweight components, then loosen the internal support bracket fasteners, and then lift the entire internal support frame out to facilitate its transport and transfer to the next well pit flow section.

[0091] Step 11: When dismantling the formwork of the pit wall, first remove the guide positioning components at the bottom of the pit, then remove the wall formwork of the four sides of the pit, and then remove the four corner formwork. The bottom formwork is dismantled piece by piece and lifted out of the pit. Clean the pit formwork box, apply release agent, hoist it to the outside of the site, and then transport it to the formwork storage area and mark the formwork serial number to prevent incorrect use order.

[0092] Step 12: When constructing a section of the project or the next construction site, repeat steps 3 through 11.

[0093] Example 3, combined with Figures 1 to 4 This embodiment further discloses the following:

[0094] For the construction of elevator shaft pits in a residential building project, prefabricated pit formwork was used for the specific construction.

[0095] Prefabricated pit formwork consists of three parts: pit bottom formwork system, pit wall formwork system, and counterweight support system.

[0096] The first part of the pit bottom formwork system includes a bottom formwork structure with vents and supporting timber. The bottom formwork structure is 5mm-10mm thick, and the timber is 40mm x 80mm. The second part of the pit wall formwork system includes corner formwork, central formwork, reinforcing triangular blocks or plates, and supporting connectors. The hoisting holes in the pit wall formwork system are Ф50 holes. Construction includes the following:

[0097] According to the sample drawings, the bottom formwork, wall formwork, and ballast support frame formwork of the well pit are made from materials such as wooden templates, timber, steel pipes and fasteners at the processing plant.

[0098] Before installing the pit formwork, the construction of the supporting reinforcement under the pit formwork bottom plate should be completed concurrently with the pit reinforcement construction. Based on the size of the pit formwork and the internal anti-buoyancy load, support points need to be appropriately set at the lower positions of the pit wall formwork and the pit bottom uprights.

[0099] The installation sequence of the manhole formwork system is as follows: first, the positioning lines are marked out, then the bottom formwork system of the manhole is hoisted, then the wall formwork system of the manhole is installed, and finally the internal counterweight support frame of the manhole is hoisted.

[0100] The pit wall formwork system is hoisted using pre-drilled hoisting holes on the four sides of the formwork. Steel wire ropes are threaded through these four points for hoisting. A 50mm long φ48 short steel pipe is first placed inside the hole to prevent damage; rubber pads are also added when threading the steel wire rope. After the pit wall formwork is installed, the short steel pipe must be removed, and the hoisting holes temporarily sealed to prevent grout leakage. The pit wall formwork is placed on top of the bottom formwork to facilitate subsequent removal of the large formwork. After the pit wall formwork is placed and its position adjusted, positioning timbers should be firmly placed at the base of the ribs of the four wall formwork sections and fixed to the bottom formwork using extended screws spaced 200mm apart to prevent movement during pouring. After placing the steel pipe counterweight support frame inside the pit formwork box, additional supports and main steel pipe back ribs need to be installed around the pit wall to effectively prevent buoyancy and resist the lateral pressure generated by the pouring of the pit wall concrete. Finally, place an appropriate amount of counterweight on the pit mold box, such as wooden blocks or steel pipes (as determined by calculation), to prevent the pit mold box from floating.

[0101] Following the construction principle of dismantling the formwork in the order of the first to be erected and the last to be erected, the formwork is dismantled in an orderly manner. The dismantling time is based on not damaging the poured concrete of the trench or pit, and avoiding chipped edges or corners. Generally, it can be carried out when the concrete strength reaches 1.2MPa. However, care should be taken to avoid delays in dismantling, which could lead to difficulties in dismantling. For the dismantling of the pit formwork, first remove the counterweights, then loosen the supports, and then lift the steel pipe support frame. The support frame is suitable for being lifted out as a whole for easy transport and transfer to the next pit flow section. When dismantling the pit wall formwork, first remove the positioning wooden blocks at the bottom of the pit, then remove the large formwork in the middle of the four walls of the pit, and then remove the four corner formwork. Since the pit wall formwork is dismantled into several large formwork pieces, in order to facilitate reuse, achieve multiple flow and turnover, and improve utilization, it is necessary to protect each component during the dismantling process. The pit bottom formwork is dismantled piece by piece and lifted out of the pit. The pit formwork is cleaned, a release agent is applied, and it is transported to the next flow section for later use.

[0102] During construction, the connections between the triangular blocks and corner molds on the pit wall formwork, and between the corner molds and intermediate molds, are all made using 60mm extended self-tapping screws. This allows for easy disassembly with an electric screwdriver, and the self-tapping screws can be reused multiple times, actively practicing material-saving and consumption-reducing construction. The connection between the pit wall formwork and the bottom formwork uses a side-pressing bottom method to facilitate subsequent formwork removal. Combined with the method of installing the bottom formwork as a whole and disassembling it piece by piece, to facilitate continuous turnover, it is advisable to prepare an extra set of the bottom formwork system. A non-removable wire mesh is installed inside the vent holes, 200mm wider on each side than the hole edge. A hollow, 200mm high template box of the corresponding size is installed inside the hole to remove air bubbles and prevent concrete from overflowing onto the bottom formwork during pouring, which would hinder subsequent bottom formwork removal.

[0103] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A prefabricated pit formwork construction method, which adopts a prefabricated formwork construction system for building pits. The prefabricated formwork construction system for building pits includes a pit bottom formwork system, a pit wall formwork system, a counterweight support system, and a stress monitoring system. The pit bottom formwork system includes a bottom formwork component and a guide and positioning component on the bottom formwork component. The bottom formwork component is provided with venting holes. The pit wall formwork system includes corner formwork, middle formwork, template locking vertical plate assembly and reinforcing fixed top plate. The four middle formworks are placed in a quadrilateral shape, and a set of corner formworks is set between adjacent middle formworks. The upper end of the corner formwork is connected to the middle formwork through the reinforcing fixed top plate. The inner end of the corner mold is provided with a first locking support plate, and the inner end of the middle mold is provided with a second locking support plate. The first locking support plate is connected to the second locking support plate through the template locking vertical plate assembly. The counterweight support system includes an internal support mechanism installed inside the wall formwork and a counterweight assembly installed at the upper end of the internal support mechanism. The internal support mechanism includes an internal support frame, a back brace frame, and an internal support bracket fastener. The counterweight assembly is connected to the upper end of the internal support frame and the pit wall formwork system. The force monitoring system includes a central monitoring controller and a sensor support mechanism. The sensor support mechanism is connected to the side end of the inner support frame. The sensor support mechanism includes a first force support plate, a second force support plate, and multiple electro-hydraulic support columns disposed between the first force support plate and the second force support plate. The outer end of the second force support plate is connected to a snap-on support shaft. The upper end of the inner support frame and the buckle support shaft are both connected to inner support bracket buckles; the back brace frame is located around the inner support frame and is pressed against the inner end face of the wall mold through the inner support bracket buckles, characterized in that... The specific construction methods for prefabricated pit formwork include the following: Step 1: In the processing yard, based on the processing sample drawing, determine the quantity of wooden templates, wooden poles, steel pipes, and fasteners used in the pit bottom formwork system, pit wall formwork system, and counterweight support system. Determine the height of the corner formwork and middle formwork in the pit wall formwork system. Then process the bottom formwork assembly, corner formwork, middle formwork, template locking vertical plate assembly, and reinforced top plate, and assemble the internal support mechanism and counterweight assembly. Step 2: In the processing yard, the bottom formwork assembly and the middle formwork need to be trial-assembled in advance. During the trial assembly, two end positioning blocks with a size of 40mm×80mm×200mm are first installed on the corner of the diagonal line inside the bottom plate. The end positioning blocks are placed flat on one side of the bottom rib, and the two end positioning blocks are tongue and groove connected to ensure that the middle formwork can be quickly and accurately aligned and positioned during hoisting. The remaining two positioning wooden blocks are added after the middle formwork is in place. Step 3: Before installing the formwork structure of the pit, during the construction of the pit reinforcement, the construction of the supporting reinforcement under the bottom plate should be completed in between; according to the size of the pit formwork and the internal anti-buoyancy load, support points need to be reasonably set at the lower position of the pit wall formwork and the pit bottom uprights. The support points are used to support the bottom formwork components. Step 4: Before construction, clarify the installation sequence of the well pit formwork system as follows: first, mark the positioning lines, then hoist the bottom formwork system of the well pit, then install the well pit wall formwork system, and finally hoist the counterweight support system. Step 5: Hoist the bottom formwork assembly onto the support ribs at the bottom of the pit and ensure the stability of the support hoist; check whether the guide positioning assembly has shifted position. After confirming that there is no shift or adjusting the position, add rivets for secondary fixation. Step Six: When hoisting the pit wall formwork system, use the formwork hoisting holes pre-drilled on the wall formwork within the pit wall formwork system. Thread steel wire ropes through the formwork hoisting holes for hoisting. Before hoisting with steel wire ropes, place a 50mm long short steel pipe inside the formwork hoisting hole. Add rubber pads to the short steel pipe to provide support and prevent damage to the hoisting hole. After installing the pit wall formwork, remove the short steel pipe and temporarily seal the hoisting hole to prevent grout leakage. Step 7: After placing the pit wall formwork, check the position of the middle wall formwork and the corner wall formwork. Place positioning wooden blocks at the base of the wall formwork ribs around the middle wall formwork and fix them to the bottom formwork using extended screws spaced 200mm apart to prevent movement during the pouring process. Step 8: When constructing the counterweight support system, first place the inner support frame, then install the back bracing frame around the perimeter, and then use the pipe connecting bolts to adjust and lock the snap-fit ​​position of the inner support bracket fastener. The inner support frame and support components are used to prevent buoyancy and resist the lateral pressure generated by the concrete pouring of the pit wall. Step 9: Install the counterweight assembly onto the inner support frame and the pit wall formwork system. The load-bearing body of the counterweight assembly is the counterweight support shell. After the counterweight support shell is hoisted, place a certain amount of weight inside the counterweight support shell to prevent the pit formwork box from floating. Step 10: Following the construction principle of removing the formwork last and removing the formwork first, the formwork should be removed when the concrete strength reaches 1.2MPa. When dismantling the well pit formwork, first remove the counterweight components, then loosen the inner support bracket fasteners, and then lift the inner support frame as a whole and lift it out for easy transport and transfer to the next well pit flow section. Step 11: When dismantling the formwork of the pit walls, first remove the guide positioning components at the bottom of the pit, then remove the wall formwork of the four sides of the pit, and then remove the corner formwork. The bottom formwork is dismantled piece by piece and lifted out of the pit. Clean the pit formwork box, apply release agent, hoist it to the outside of the site, and then transport it to the formwork storage area and mark the formwork serial number to prevent incorrect use order. Step 12: When constructing a section of the project or the next construction site, repeat steps 3 through 11.

2. The prefabricated pit formwork construction method according to claim 1, characterized in that, The bottom mold assembly includes a bottom plate and multiple bottom ribs connected to the inner end of the bottom plate. The bottom plate is rectangular and the multiple bottom ribs are arranged parallel to each other on the bottom plate by rivets. The guide positioning assembly includes a central positioning block and end positioning blocks. There are four end positioning blocks, which are respectively connected to the four corners of the base plate and connected to the bottom rib. There are multiple central positioning blocks, which are evenly distributed at the upper middle part of the base plate.

3. The prefabricated pit formwork construction method according to claim 1, characterized in that, The corner mold includes a first L-shaped support plate and multiple bracket ribs connected to the outer end of the first L-shaped support plate; there are multiple first locking support plates, and after the multiple first locking support plates are vertically spaced, the first locking support plates are vertically connected to the first L-shaped support plate.

4. The prefabricated pit formwork construction method according to claim 3, characterized in that, There are multiple second locking support plates, and the multiple second locking support plates are arranged vertically at intervals; The template locking vertical plate assembly includes multiple locking units, each including a locking sleeve plate and a locking bolt. Locking through holes are provided in the locking sleeve plate, the first locking support plate, and the second locking support plate. After the locking sleeve plate is snapped onto the outer end of the first locking support plate and the outer end of the second locking support plate, it is fixed by locking bolts. At this time, the locking bolts pass through the locking through hole and are connected to the corner mold.

5. The prefabricated pit formwork construction method according to claim 3, characterized in that, The wall-mounted mold includes multiple wall-mounted vertical rods, wall-mounted horizontal rods connected to the upper and lower ends of the wall-mounted vertical rods, first vertical plates set at the front and rear ends of the wall-mounted vertical rods, and second vertical plates set at the left and right ends of the wall-mounted horizontal rods. The second vertical plates are connected to the first L-shaped support plate through wall-mounted fixing screws. At this time, the wall-mounted fixing screws pass through the first L-shaped support plate and are connected to the wall-mounted vertical rods.

6. The prefabricated pit formwork construction method according to claim 5, characterized in that, The reinforced fixed top plate is triangular in shape, and there are four reinforced fixed top plates. The reinforced fixed top plates are connected to the upper end of the first L-shaped support plate and the crossbar in the wall by rivets.

7. The prefabricated pit formwork construction method according to claim 5, characterized in that, The inner support frame includes three sets of vertical tube assemblies and three sets of planar support frames. Each set of vertical tube assemblies includes three horizontally parallel inner support vertical tubes, and the three sets of vertical tube assemblies are arranged in parallel to each other in the longitudinal direction. The three sets of planar support frames are arranged in parallel to each other in the vertical direction, and the planar support frames are connected to the inner support vertical tubes through the first tube body connector. The planar support frame includes a set of horizontal tube assemblies and a set of vertical tube assemblies. The horizontal tube assembly includes three parallel inner support horizontal tubes, and the vertical tube assembly includes three parallel inner support vertical tubes. The inner support horizontal tubes are located at the upper end of the inner support vertical tubes, and the inner support horizontal tubes are connected to the inner support vertical tubes through a second tube body connector.

8. The prefabricated pit formwork construction method according to claim 7, characterized in that, The inner support bracket fastener includes a U-shaped snap-fit ​​plate and a support bracket connected to the U-shaped snap-fit ​​plate. The first force-bearing support plate and the second force-bearing support plate are both strip steel plates. The first force-bearing support plate is connected to the outside of both the horizontal tube assembly and the vertical tube assembly. A vertical support is connected to the inner support tube, and a battery pack is connected to the vertical support. The battery pack is connected to the electro-hydraulic support column via wires, and a pressure sensor is connected to the end of the electro-hydraulic support column.

9. The prefabricated pit formwork construction method according to claim 1, characterized in that, The counterweight assembly includes a counterweight support plate and a counterweight support shell connected to the counterweight support plate. A partition plate is provided inside the counterweight support shell. After the partition plate and the counterweight support shell are connected, multiple weight placement cavities are formed. A counterweight block or counterweight sandbag is provided in the weight placement cavity. The counterweight support plate includes a counterweight plate body and a counterweight support timber connected to the lower end of the counterweight plate body. A counterweight cover is provided at the upper end of the counterweight support shell, and counterweight lifting hooks are provided at the side ends of the counterweight support shell and the side ends of the counterweight plate body.

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