Construction method of self-bearing formwork of sleeve-arched arch frame

Abstract

This invention relates to a convenient support construction method for a self-supporting formwork of a double-arched tunnel, comprising the following steps: positioning and installation of the steel arch frame, which further includes steel arch frame assembly, measurement and positioning, and welding of guide steel pipes; concrete foundation pouring; formwork and welding of water-stop bolts; concrete pouring; and curing. This invention utilizes the steel arch frame itself as the support system for the double-arched tunnel concrete construction. Water-stop bolts connect the bottom formwork, steel arch frame, double-arched tunnel concrete layer, and outer formwork into a single, stable support system. This truly allows a single arch frame to serve two purposes. Compared to existing tunnel formwork support construction methods, this significantly reduces the input of support materials. Using this support system broadens the range of construction conditions, easily solves the problem of difficult formwork installation due to poor terrain conditions in traditional construction, reduces the amount of excavation required for tunnel entry, and aligns with the tunnel construction concept of "early entry and late exit."

Description

Technical Field

[0001] This invention belongs to the field of tunnel construction technology, specifically relating to a convenient support construction method for a self-supporting formwork for an arch frame. Background Technology

[0002] Currently, there are generally two formswork support methods for advanced pipe shed construction in traditional tunnels. One is double-arch support, where one arch serves as the formwork support and the other as the structural stiffener; the other involves supporting multiple steel frames or full-span scaffolds to form a support system for the formwork's load-bearing capacity. Traditional tunnel formwork support methods have the following problems when performing arch-supported construction: 1. They often require a large investment of support materials, resulting in high construction costs; 2. They have high requirements for construction conditions, especially in steep rock faces lacking space for support frame erection, where excavation and core soil placement are difficult, and where surrounding rock conditions are poor. This not only increases construction difficulty and work efficiency but also makes it difficult to ensure the stability of the formwork support, posing a risk of formwork bursting. Furthermore, the limited working space leads to poor arch-supported construction results. Therefore, it is necessary to propose a simple and easy-to-construct tunnel formwork support device and its construction method to replace the traditional double-arch support and the combined arch and steel pipe support, solving the problems of difficult arch-supported construction, low efficiency, unstable support, poor arch-supported formation, and high construction costs associated with traditional support methods. Summary of the Invention

[0003] To address the above problems, this invention provides a convenient support construction method for self-supporting arch frame templates.

[0004] The specific technical solution is: a convenient support construction method for self-supporting arch frame templates, characterized by the following steps:

[0005] S1: Steel arch frame positioning and installation: The arch frame is installed outside the outer contour line of the tunnel lining, close to the tunnel face. The arch frame construction allows for settlement deformation. S1 specifically includes the following steps:

[0006] S1-1: Steel arch frame assembly: The steel arch frame consists of several units. Each unit is made up of a steel frame, connecting steel plates, and is welded together. The steel frames of two adjacent units are welded and fixed together. The connecting steel plates of two adjacent units are connected by bolts. Each unit is assembled into a steel arch frame. The number of steel arch frames is determined according to the actual length of the arch frame. The connecting ribs between adjacent steel arch frames are welded and fixed together. After the assembly is completed, the formwork is erected.

[0007] S1-2: Measurement and Positioning: To facilitate the erection of the formwork, measure and position the arch foot of the arch frame, and after compacting and leveling the arch foot, install the steel arch frame.

[0008] S1-3: Guide steel pipe welding: Longitudinal welded seamless steel pipes are used as guide steel pipes. After the guide steel pipes are positioned, they are welded to the steel arch frame with steel bars to ensure that the guide pipes do not move or deform during concrete pouring.

[0009] S2: Concrete foundation pouring: Pour the concrete foundation, and control the pouring height within the elevation of the arch foundation.

[0010] S3: Formwork erection and water-stop bolt welding: The formwork is processed according to the outline of the steel arch frame. Before erecting the formwork, the formwork is assembled first. Bolt holes are drilled in the assembled bottom formwork and outer formwork. Then, the bottom formwork is erected first, and then the water-stop bolts are inserted into the bolt holes, so that they pass vertically through the bottom formwork and the steel arch frame. At the same time, the water-stop bolts are welded and fixed to the steel arch frame. Then, the outer formwork is erected, so that the water-stop bolts pass through the bolt holes on the outer formwork. Finally, double-jointed steel pipes and butterfly buckles are installed at both ends of the water-stop bolts. The double-jointed steel pipes are tightened by rotating the butterfly buckles to achieve the reinforcement of the arch formwork. The end formwork is installed in the same normal direction and is firmly connected.

[0011] S4: Concrete pouring: Concrete pouring shall be carried out in symmetrical layers on both sides. The height difference between the two layers of concrete shall not exceed 40cm. When vibrating the concrete, the vibrator shall be inserted vertically and inserted 5-10cm into the previous layer of concrete to ensure a tight bond between the two layers of concrete.

[0012] S5: Curing treatment: After the concrete strength reaches 50%, start loosening the outer nut of the water-stop screw. After the strength reaches 100%, cut both ends of the screw to ensure that the screw end is below the concrete structure surface and perform anti-rust treatment. After demolding, water curing should be carried out in time. After the strength reaches the requirements, use 1:2 cement mortar to seal the pit to ensure that the waterproofing is in place.

[0013] Furthermore, the settlement variable mentioned in step S1 is 10 cm.

[0014] Furthermore, the bolt strength in step S1-1 is not less than M30, and the diameter of the connecting ribs is 16mm and the spacing is 100cm.

[0015] Furthermore, in steps S1-3, the slope of the guide tube installation is controlled to be 3° upward, and the external insertion angle of the left and right guide tubes is 1°~1.5°.

[0016] Furthermore, in step S3, the diameter of the water-stop screw is 14mm, the thickness of the template is 5cm, the spacing of the bolt holes is 45cm×45cm, and the diameter of the double-jointed steel pipe is 22mm.

[0017] The beneficial effects of this invention are as follows: This invention utilizes the steel arch frame of the arch itself as the support system for the concrete construction of the arch. Water-stop bolts connect the bottom formwork, steel arch frame, arch concrete layer, and outer formwork into a single, stable support system. This truly allows a single arch frame to perform two functions—formwork and support. Compared to existing tunnel formwork support arch construction, this significantly reduces the input of support materials. Using this support system broadens the range of construction conditions, easily solving the problem of difficult formwork installation due to poor terrain conditions in traditional construction, reducing the amount of excavation required for tunnel entry, and conforming to the tunnel construction concept of "early entry and late exit." Furthermore, this support system is quick and efficient to install on-site, greatly simplifying the construction process, significantly reducing labor intensity, and improving construction progress. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a single steel arch frame of the present invention;

[0019] Figure 2 This is a schematic diagram of the multi-span steel arch frame of the present invention;

[0020] Figure 3 yes Figure 2 Top view;

[0021] Figure 4 yes Figure 1 , Figure 2 Schematic diagram of the connection between the steel arch frames of each unit;

[0022] Figure 5 This is a schematic diagram of the convenient support device for the self-supporting arch frame template of the present invention;

[0023] Figure 6 This is a cross-sectional view of the construction process of the present invention;

[0024] Figure 7 This is a cross-sectional view of the construction process of the existing double-arch support;

[0025] Figure 8 This is a cross-sectional view of the existing arch frame + bracket support construction process;

[0026] In the diagram: 1-steel arch frame, 101-steel frame, 102-connecting steel plate, 103-erecting steel plate, 2-connecting reinforcement, 3-water-stop bolt, 4-double-jointed steel pipe, 5-bottom formwork, 6-outer formwork, 7-end formwork, 8-arch concrete layer, 9-support, 10-reserved core soil. Implementation

[0027] To make the technical problems and solutions solved by the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention. Example

[0028] like Figure 1 This embodiment provides a convenient support device for a self-supporting arch frame template, including a steel arch frame 1, connecting ribs 2, water-stop bolts 3, and 4 double-jointed steel pipes; wherein, the steel arch frame 1 is composed of several units, each unit is welded together by a steel frame 101, connecting steel plates 102, and supporting steel plates 103 (wherein the welding rod is E42 type, the weld length of the connecting part in the steel frame is full weld, and the weld height is not less than 6mm), the steel frames 101 of two adjacent units are welded and fixed at the connection, and the connecting steel plates 102 of two adjacent units are connected by bolts (the bolt holes and bolt sizes match), and each unit is assembled to form a steel arch frame 1; wherein the supporting steel plates are the steel plates of the steel arch frame that are in contact with the ground, and are horizontally erected on the concrete surface;

[0029] The number of steel arch frames 1 can be flexibly determined according to the actual length of the arch frame. Adjacent steel arch frames 1 are fixed by welding with connecting ribs 2 (φ16mm), and the distance between adjacent steel arch frames is no more than 50cm.

[0030] A bottom formwork 5 is erected on the inner wall of the steel arch frame 2. The bottom formwork 5 is secured to the inner wall of the steel arch frame 2 by several water-stop bolts 3 and double-jointed steel pipes 4 (φ22mm). The water-stop bolts 3 pass vertically through the bottom formwork 5 and the steel arch frame 2. The end of the water-stop bolt 3 closest to the inner wall of the bottom formwork 5 is secured to the double-jointed steel pipe 4 by a butterfly buckle. The contact point between the water-stop bolt 3 and the steel arch frame 2 is welded to the steel arch frame 2. The end of the water-stop bolt 3 away from the steel arch frame 2 passes through the arch-encasing concrete layer and the outer formwork 6, and is secured to the double-jointed steel pipe 4 of the outer formwork 6 by a butterfly buckle, thus reinforcing the arch-encasing formwork. The water-stop bolts 3 and double-jointed steel pipes 4 are used together, with a spacing of 45cm×45cm. Example

[0031] This embodiment provides a construction method using a convenient support device for a self-supporting formwork of a sleeve arch frame, including the following steps:

[0032] S1: Positioning and Installation of Steel Arch Frame: The arch frame is installed outside the outer contour line of the tunnel lining, close to the tunnel face. A 10cm settlement deformation allowance is reserved during the arch frame construction. S1 specifically includes the following steps:

[0033] S1-1: Steel Arch Frame Assembly: Steel arch frame 1 consists of several units. Each unit is constructed by welding steel profiles, connecting steel plates, and erecting the frame (using E42 welding rods, full welding, and a weld height of not less than 6mm). The steel profiles of two adjacent units are welded and fixed at the connection point. The connecting steel plates of two adjacent units are connected by bolts (bolt strength not less than M30). Each unit is assembled into a steel arch frame. The number of steel arch frames is determined according to the actual length of the arch frame. Connecting ribs (connecting rib diameter φ16mm, spacing 100cm) are welded and fixed between adjacent steel arch frames. After assembly, the formwork is erected.

[0034] S1-2: Measurement and Positioning: To facilitate the erection of the formwork, measure and position the arch foot of the arch frame, and after compacting and leveling the arch foot, install the steel arch frame.

[0035] S1-3: Welding of Guide Steel Pipes: The longitudinally welded seamless steel pipe serves as the guide steel pipe, and its direction and slope must be strictly controlled. Considering that the slope of the line and the drilling tool drift and sag during drilling will cause drilling deviation, the slope of the guide pipe is controlled to be 3° upward when it is installed. At the same time, the left guide pipe is inserted outward by 1°~1.5°, and the right guide pipe is inserted outward by 1°~1.5°. After the guide steel pipe is positioned, the guide pipe is welded to the steel arch frame with steel bars to ensure that the guide pipe does not move or deform when pouring concrete.

[0036] S2: Concrete foundation pouring: Concrete foundation pouring is carried out. C25 concrete is used, and the pouring height is controlled within the elevation of the arch foundation.

[0037] S3: Formwork and Welding of Water-Stop Bolts: The bottom formwork, outer formwork, and end formwork are processed according to the outline of the steel arch frame. All are made of wood with a thickness of 5cm. Before setting up the formwork, the formwork is assembled. Bolt holes are drilled at 45cm x 45cm intervals on the assembled bottom and outer formwork. The bottom formwork is then erected first, followed by inserting φ14 water-stop bolts into the bolt holes, allowing them to pass vertically through the bottom formwork and the steel arch frame. Simultaneously, the water-stop bolts are welded and fixed to the steel arch frame. Then, the outer formwork is erected, allowing the water-stop bolts to pass through the bolt holes on the outer formwork. Finally, φ22mm double-jointed steel pipes and butterfly buckles are installed at both ends of the water-stop bolts. The double-jointed steel pipes are tightened by rotating the butterfly buckles, thus reinforcing the arch formwork. The end formwork is installed in the same normal direction and firmly connected to prevent movement. The formwork joints must be neat, smooth, and tightly sealed to prevent grout leakage.

[0038] S4: Concrete pouring: Concrete pouring shall be carried out in symmetrical layers on both sides. The height difference between the two layers of concrete shall not exceed 40cm. When vibrating the concrete, the vibrator shall be inserted vertically and inserted 5-10cm into the previous layer of concrete to ensure a tight bond between the two layers of concrete.

[0039] S5: Curing treatment: After the concrete strength grade reaches 50%, start loosening the outer nut of the water-stop screw. After the strength reaches 100%, cut both ends of the screw to ensure that the screw end is below the concrete structure surface and perform anti-rust treatment. After demolding, water curing should be carried out in time. After the strength meets the requirements, use 1:2 cement mortar (with 5% waterproofing agent) to seal the pit to ensure that the waterproofing is in place.

[0040] To further explain this construction method, before constructing the arch frame, C25 concrete is first laid at the arch foot to facilitate formwork erection. Considering the actual deformation allowance during construction, the height of the base is controlled within the arch frame foundation elevation. Connecting bars are used to reinforce and fix the multiple steel arch frames to the foundation concrete to further ensure the stability of its self-supporting system. After the arch frame formwork is installed, it is fixed by tie rods and double-splitter steel pipes. The tie rods are then welded and fixed on one side of the steel arch frame. At this point, the tie rods have been converted into single-sided tightening type. The bottom formwork, steel arch frame, arch frame concrete layer, and outer formwork are connected into a whole through the tie rods to form a stable support system.

[0041] This invention utilizes the steel arch frame of the arch itself as the support system for the concrete construction of the arch. A single arch frame simultaneously functions as both formwork and support. This support system, together with the concrete foundation, water-stop bolts, and double-layered steel pipes, forms an integrated system to ensure the stability of the entire formwork system. Compared to existing tunnel formwork support arch construction, this significantly reduces the input of support materials. Using this support system broadens the range of construction conditions, easily solving the problem of difficult formwork installation due to poor terrain conditions in traditional construction, reducing the amount of excavation required for tunnel entry, and conforming to the tunnel construction concept of "early entry, late exit." Furthermore, this support system is quick and efficient to install on-site, greatly simplifying the construction process, significantly reducing labor intensity, and improving construction progress.

[0042] The present invention has been described in detail above through specific and preferred embodiments. However, those skilled in the art should understand that the present invention is not limited to the embodiments described above. Any modifications, equivalent substitutions, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A convenient support construction method of a self-bearing formwork of a casing arch frame, characterized in that, Includes the following steps: S1: Steel arch frame positioning and installation: The arch frame is installed outside the outer contour line of the tunnel lining, close to the tunnel face. The arch frame construction allows for settlement deformation. S1 specifically includes the following steps: S1-1: Steel arch frame assembly: The steel arch frame consists of several units. Each unit is made up of a steel frame, connecting steel plates, and is welded together. The steel frames of two adjacent units are welded and fixed together. The connecting steel plates of two adjacent units are connected by bolts. Each unit is assembled into a steel arch frame. The number of steel arch frames is determined according to the actual length of the arch frame. The connecting ribs between adjacent steel arch frames are welded and fixed together. After the assembly is completed, the formwork is erected. S1-2: Measurement and Positioning: To facilitate the erection of the formwork, measure and position the arch foot of the arch frame, and after compacting and leveling the arch foot, install the steel arch frame. S1-3: Guide steel pipe welding: Longitudinal welded seamless steel pipes are used as guide steel pipes. After the guide steel pipes are positioned, they are welded to the steel arch frame with steel bars to ensure that the guide pipes do not move or deform during concrete pouring. S2: Concrete foundation pouring: Pour the concrete foundation, and control the pouring height within the elevation of the arch foundation. S3: Formwork erection and water-stop bolt welding: The formwork is processed according to the outline of the steel arch frame. Before erecting the formwork, the formwork is assembled first. Bolt holes are drilled in the assembled bottom formwork and outer formwork. Then, the bottom formwork is erected first, and then the water-stop bolts are inserted into the bolt holes, so that they pass vertically through the bottom formwork and the steel arch frame. At the same time, the water-stop bolts are welded and fixed to the steel arch frame. Then, the outer formwork is erected, so that the water-stop bolts pass through the bolt holes on the outer formwork. Finally, double-jointed steel pipes and butterfly buckles are installed at both ends of the water-stop bolts. The double-jointed steel pipes are tightened by rotating the butterfly buckles to achieve the reinforcement of the arch formwork. The end formwork is installed in the same normal direction and is firmly connected. S4: Concrete pouring: Concrete pouring shall be carried out in symmetrical layers on both sides. The height difference between the two layers of concrete shall not exceed 40cm. When vibrating the concrete, the vibrator shall be inserted vertically and inserted 5-10cm into the previous layer of concrete to ensure a tight bond between the two layers of concrete. S5: Curing treatment: After the concrete strength reaches 50%, start loosening the outer nut of the water-stop screw. After the strength reaches 100%, cut both ends of the screw to ensure that the screw end is below the concrete structure surface and perform anti-rust treatment. After demolding, water curing should be carried out in time. After the strength reaches the requirements, use 1:2 cement mortar to seal the pit to ensure that the waterproofing is in place.

2. The convenient support construction method for self-supporting formwork of arch frame according to claim 1, characterized in that, The settlement deformation amount mentioned in step S1 is 10cm.

3. The convenient support construction method for a self-supporting formwork for an arch frame as described in claim 1, characterized in that, The bolt strength in step S1-1 is not less than M30, and the diameter of the connecting ribs is 16mm and the spacing is 100cm.

4. The convenient support construction method for self-supporting formwork of arch frame according to claim 1, characterized in that, In steps S1-3, the slope of the guide tube installation is controlled to be 3° upward, and the external insertion angle of the left and right guide tubes is 1°~1.5°.

5. The convenient support construction method for a self-supporting formwork of a sleeve arch frame according to claim 1, characterized in that, In step S3, the diameter of the water-stop screw is 14mm, the thickness of the template is 5cm, the spacing of the bolt holes is 45cm×45cm, and the diameter of the double-jointed steel pipe is 22mm.

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