Immersed tube tunnel inner mold structure and immersed tube prefabrication construction method

Abstract

The immersed tube tunnel inner mold structure comprises the immersed tube tunnel inner mold structure composed of an inner top mold plate, an upper haunch mold plate, a lower haunch mold plate and an inner supporting assembly, and the inner supporting assembly is provided with a first telescopic driving part, a second telescopic driving part and a lifting driving part for controlling the mold plates to be unfolded or folded. The invention further discloses an immersed tube prefabrication construction method adopting the internal mold structure. The immersed tube prefabrication construction method comprises the steps of building the external mold plate, pouring the foundation section, building the internal mold, pouring the vertical wall section and the top wall section, binding post-cast strip steel bars, pouring the post-cast strip and the like. According to the device, the technical effects that mounting and dismounting of the immersed tube tunnel inner mold are facilitated, efficient demolding is achieved, the working platform can be formed, post-cast strip steel bar binding is facilitated, and it is ensured that immersed tube prefabrication construction is conducted smoothly are achieved.

Description

Technical Field

[0001] This application relates to the field of immersed tunnel prefabrication construction, and in particular to an internal formwork structure for immersed tunnels and a method for immersed tunnel prefabrication construction. Background Technology

[0002] Immersed tunnels, as an important component of underwater transportation infrastructure, have been widely used in recent years due to the continuous growth in transportation demand and advancements in engineering technology. The construction of immersed tunnels is of great significance for crossing rivers, straits, and other waterways, shortening transportation distances, and promoting regional economic development. They can effectively alleviate water traffic pressure, improve transportation efficiency, and also provide new space for urban development and expansion.

[0003] In the construction of immersed tunnels, the erection of the internal formwork structure is one of the key steps. Traditionally, to construct the internal formwork system for immersed tunnels, the method of assembling individual formwork pieces on-site is usually adopted. Workers need to hoist each formwork component to the construction site one by one, and then connect and fix them using bolts, welding, and other methods. This method is not only cumbersome to operate, but also requires a high level of skill from the workers. In addition, some construction projects use monolithic formwork, directly hoisting and installing pre-fabricated large formwork, but the handling and positioning of this formwork is more difficult, and its subsequent dismantling also presents many inconveniences.

[0004] Existing methods of constructing internal formwork have significant drawbacks. When assembling individual formwork components on-site, the large number of components leads to accumulated errors, resulting in loose joints and affecting the quality of the immersed tunnel. Furthermore, the long assembly time increases the construction period. While monolithic formwork reduces assembly workload to some extent, its large size and weight require large equipment for transportation and installation, resulting in poor flexibility and difficulties in later demolding, making it difficult to meet the requirements of efficient and precise construction. Summary of the Invention

[0005] To improve the efficiency of immersed tunnel construction, this application provides an internal formwork structure for immersed tunnels and a method for prefabricating immersed tunnel sections. This application provides an internal formwork structure for immersed tunnels and a method for prefabricating immersed tunnel sections, employing the following technical solution: An internal formwork structure for an immersed tunnel includes an inner top formwork, two upper axle corner formworks, two lower axle corner formworks, and an internal support assembly. The inner top formwork is positioned above the internal support assembly. The two upper axle corner formworks are hinged to both sides of the inner top formwork. The two lower axle corner formworks correspond one-to-one with the two upper axle corner formworks. The end of each upper axle corner formwork furthest from the internal support assembly is hinged to the corresponding lower axle corner formwork. The internal support assembly is equipped with a first telescopic drive for expanding or contracting the upper axle corner formworks. A second telescopic drive is provided between the lower axle corner formworks and the upper axle corner formworks for expanding or contracting the lower axle corner formworks. A lifting drive is provided at the bottom of the internal support assembly. The lifting drive forces the internal support assembly and the inner top formwork upward by lifting downward and forces the support assembly and the inner top formwork downward by contracting. During the prefabrication of the immersed tube, the lifting drive unit drives the inner support assembly and the inner top template to rise and be in place. The first telescopic drive unit extends to drive the upper armpit corner template to unfold and be in place. The second telescopic drive unit extends to drive the lower armpit corner template to unfold and be in place. The inner top template, the upper armpit corner template and the lower armpit corner template constitute the immersed tube inner mold system. After the precast tunnel section is completed, the second telescopic drive retracts to drive the lower armpit corner template to retract inward and demold; the first retraction drive retracts to drive the upper armpit corner template to retract inward and demold; the lifting drive retracts to drive the inner top template to descend and demold.

[0006] By adopting the above technical solution, the first telescopic drive component of the internal support assembly can flexibly expand or contract the upper armpit corner template, and the second telescopic drive component can flexibly expand or contract the lower armpit corner template. The lifting drive component can move the internal support assembly and the inner top template up and down. During the precast tunnel construction, the internal formwork system of the tunnel can be constructed quickly and accurately, improving construction efficiency. After construction, each template can be easily demolded, facilitating subsequent operations. At the same time, the hinged design between each template ensures the flexibility of the expansion and contraction process, which is conducive to achieving automated control and reducing manual intervention and labor intensity.

[0007] Preferably, the inner support assembly includes a gantry body and a support frame. The top of the gantry body is fixed to the lower surface of the inner top template and provides support for the inner top template. The support frame is fixed to the inner side of the upper armpit corner template and serves as a reinforcement.

[0008] By adopting the above technical solutions, the inner top formwork is supported by the main body of the gantry, which can ensure the stability of the inner top formwork during use; the support frame reinforces the upper haunch corner formwork on both sides of the inner top formwork, which can enhance the structural strength of the upper haunch corner formwork and make the entire immersed tunnel inner formwork structure more stable and reliable.

[0009] Preferably, the lifting drive component includes a lifting hydraulic cylinder located at the lower part of the gantry.

[0010] By adopting the above technical solution, during the prefabrication of immersed tunnel, the lifting hydraulic cylinder can lift the inner support components and the inner top template into place by lifting downwards. After the construction is completed, the inner support components and the inner top template can be lowered and demolded by retracting, which effectively realizes the lifting action of the inner top template and meets the construction and demolding requirements of the inner formwork structure of the immersed tunnel.

[0011] Preferably, the inner support assembly further includes a first inner top rod and a first outer top rod. One end of the first outer top rod is hinged to the telescopic end of the first telescopic drive member, and the other end is hinged to the support frame. The first outer top rod is provided with a first connection point. One end of the first inner top rod is hinged to the first connection point of the first outer top rod, and the other end is hinged to the gantry. The first outer top rod is provided with a first outer positioning hole. The first inner top rod is provided with a first inner positioning hole. When the upper armpit corner template is fully extended and positioned under the drive of the first telescopic drive member, the first inner positioning hole of the first inner top rod is aligned with the first outer positioning hole of the first outer top rod, and the first inner top rod and the first outer top rod are in a straight line. The first inner positioning hole and the first outer positioning hole are connected by a pin to achieve the locking purpose between the first inner top rod and the first outer top rod, so as to form a support system between the gantry and the support frame.

[0012] By adopting the above technical solution, after the first telescopic drive component drives the upper haunch corner template to unfold and be in place, the first inner push rod and the first outer push rod can be locked together by using the pins passing through the aligned positioning holes, forming a support system between the gantry and the support frame. This enhances the support stability of the inner support component for the upper haunch corner template, ensures that the upper haunch corner template remains stable during the precast tunnel construction, and improves construction quality and safety.

[0013] Preferably, the inner support assembly further includes a second inner top rod and a second outer top rod. One end of the second outer top rod is hinged to the telescopic end of the second telescopic drive member, and the other end is hinged to the support frame. The second outer top rod is provided with a second connection point. One end of the second inner top rod is hinged to the second connection point of the second outer top rod, and the other end is hinged to the inner side of the underarm corner template. The second outer top rod is provided with a second outer positioning hole. The second inner top rod is provided with a second inner positioning hole. When the underarm corner template is fully extended and positioned under the drive of the second telescopic drive member, the second inner positioning hole of the second inner top rod is aligned with the second outer positioning hole of the second outer top rod, and the second inner top rod and the second outer top rod are in a straight line. The second inner positioning hole and the second outer positioning hole are connected by a pin to achieve the locking purpose between the second inner top rod and the second outer top rod, so as to form a support system between the support frame and the underarm corner template.

[0014] By adopting the above technical solution, the second inner top rod and the second outer top rod of the inner support component can be aligned with the outer positioning hole of the second inner top rod and form a straight line when the second telescopic drive component drives the underarm corner template to be fully unfolded and positioned. The two are then locked together by using a pin, which can form a stable support system between the support frame and the underarm corner template, ensuring the stability of the underarm corner template during the precast tunnel construction, and improving the construction quality and safety.

[0015] Preferably, a central walking channel is connected to the front end of the inner top formwork, and a side walking channel is connected to the front end of the upper haunch corner formwork. The side walking channel moves synchronously with the upper haunch corner formwork. When the inner formwork of the immersed tunnel is unfolded, the side walking channel unfolds with the upper haunch corner formwork and connects with the central walking channel to form a working platform. The working platform is used for the reinforcement binding work at the post-pouring strip position.

[0016] By adopting the above technical solution, a central walking channel is set at the front end of the inner top formwork, and a side walking channel is set at the front end of the upper haunch corner formwork that moves synchronously with the upper haunch corner formwork. When the inner formwork of the immersed tunnel is unfolded, the side walking channel unfolds with the upper haunch corner formwork and connects with the central walking channel to form a working platform, which can provide working space for the reinforcement binding work at the post-pouring strip position and facilitate construction operations.

[0017] A prefabrication construction method for immersed tunnels, employing an internal formwork structure for immersed tunnels, includes the following steps: S1: Construct the outer bottom template, the outer templates on both sides of the immersed tunnel segment, and the end templates at both ends of the immersed tunnel segment, and then pour the horizontal foundation section at the bottom of the immersed tunnel segment. S2: Construct the inner formwork structure for the immersed tube on the surface of the horizontal foundation section; S3: Activate the lifting drive to drive the inner support assembly and the inner top template to rise and be in place. Activate the first telescopic drive to extend the first telescopic drive to drive the upper armpit corner template to unfold and be in place. Activate the second telescopic drive to extend the second telescopic drive to drive the lower armpit corner template to unfold and be in place. The inner top template, the upper armpit corner template and the lower armpit corner template constitute the inner mold system of the immersed tube. S4: Build the external formwork structure, pour the vertical wall sections on both sides and in the middle of the immersed tunnel segment, and finally pour the horizontal top wall section at the top of the immersed tunnel segment to form the immersed tunnel segment. A post-pouring strip is formed between adjacent immersed tunnel segments. S5: Tie reinforcing bars at the post-cast strip between adjacent immersed tube segments, and finally carry out the post-cast strip pouring construction.

[0018] By adopting the above technical solution, the outer bottom formwork, outer side formwork, and end formwork are erected sequentially according to the construction method, and the horizontal foundation section is poured. Then, the inner formwork structure of the immersed tube is erected. The inner top formwork, upper armpit corner formwork, and lower armpit corner formwork are positioned using the lifting drive, the first telescopic drive, and the second telescopic drive to form the inner formwork system. After that, the outer formwork structure is erected and each section is poured to form the immersed tube segment and the post-pouring strip. Finally, the reinforcement binding and pouring of the post-pouring strip are carried out. The prefabrication construction of the immersed tube can be completed in an orderly and efficient manner, improving construction efficiency and quality, and ensuring the forming effect of the immersed tube segment.

[0019] Preferably, the outer template structure includes an outer template body, a lateral frame disposed on the outside of the outer template body, a pedestrian ladder disposed on the outside of the lateral frame, and a pedestrian passage disposed on the top of the lateral frame. The pedestrian ladder extends from the bottom of the lateral frame to the top of the lateral frame and connects with the pedestrian passage.

[0020] By adopting the above technical solution, the outer formwork body is used to cooperate with the inner formwork structure of the immersed tunnel to pour concrete to form the immersed tunnel segment. The lateral frame can support the outer formwork body and improve the stability of the outer formwork body. The pedestrian ladder and pedestrian passage facilitate construction personnel to reach the top from the bottom of the lateral frame, which is convenient for construction operations and inspection and maintenance.

[0021] In summary, this application includes at least one of the following beneficial technical effects: 1. It avoids the problems of cumbersome on-site assembly of disassembled formwork, easy accumulation of errors, and inconvenience in the transportation, placement, and dismantling of integral formwork, thus improving the convenience of construction; 2. It solved the problem of loose template splicing, thus improving the quality of the immersed tube forming process; 3. Reduced assembly time and shortened construction cycle, meeting the requirements for efficient construction; 4. Reduced demolding difficulty and improved construction flexibility. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the unfolded state of the inner formwork structure of the immersed tunnel in Embodiment 1 of this application.

[0023] Figure 2 This is a schematic diagram of the contraction state of the inner formwork structure of the immersed tunnel in Embodiment 1 of this application.

[0024] Figure 3 yes Figure 2 Enlarged diagram of point A in the middle.

[0025] Figure 4 yes Figure 2 Enlarged diagram of point B in the middle.

[0026] Figure 5This is a schematic diagram showing the location of the working platform in the inner formwork structure of the immersed tunnel in Embodiment 1 of this application.

[0027] Figure 6 This is a schematic diagram of the outer formwork structure in the immersed tube prefabrication construction method of Embodiment 2 of this application.

[0028] Figure 7 This is a schematic diagram of the external formwork structure walking device in the immersed tube prefabrication construction method of Embodiment 2 of this application.

[0029] Figure 8 This is a schematic diagram of the inner formwork structure of the post-cast strip in the immersed tube prefabrication construction method of Embodiment 2 of this application.

[0030] Explanation of reference numerals in the attached drawings: 1. Inner top template; 2. Upper armpit corner template; 3. Lower armpit corner template; 4. Inner support assembly; 41. Gantry; 42. First inner top rod; 421. First inner positioning hole; 43. First outer top rod; 431. First outer positioning hole; 432. First connection point; 44. Support frame; 45. Second outer top rod; 451. Second outer positioning hole; 452. Second connection point; 46. Second inner top rod; 461. Second inner positioning hole; 5. First telescopic drive component; 6. Second telescopic drive component; 7. Lifting drive component; 8. Working platform; 81. Side walking passage; 82. Central walking passage 9. Outer formwork structure; 91. Lateral frame; 92. Pedestrian walkway; 93. Pedestrian staircase; 94. Outer formwork body; 95. Walking device; 951. Horizontal steel frame; 952. Vertical outer cylinder; 953. Horizontal guide rail; 954. Slide seat; 955. Receiving box; 956. Walking wheel; 957. Vertical inner cylinder; 10. Post-pouring strip inner formwork structure; 101. Intermediate formwork; 102. Upper side formwork; 103. Lower side formwork; 104. First adjustment drive component; 105. Second adjustment drive component; 106. Workbench; 107. Lifting drive component; 108. Internal support frame; 109. Pulley. Detailed Implementation

[0031] The following is in conjunction with the appendix Figure 1-8 This application will be described in further detail.

[0032] Example 1 The immersed tunnel internal formwork structure provided in this application embodiment refers to... Figure 1 and Figure 2The system includes an inner top template 1, two upper axle corner templates 2, two lower axle corner templates 3, and an inner support assembly 4. The inner top template 1 is positioned above the inner support assembly 4, and the two components work together securely to provide stable support for the inner top template 1. The two upper axle corner templates 2 are hinged to both sides of the inner top template 1, allowing them to rotate flexibly relative to the inner top template 1 for easy expansion and contraction. The two lower axle corner templates 3 correspond one-to-one with the two upper axle corner templates 2. The end of an upper axle corner template 2 furthest from the inner support assembly 4 is hinged to its corresponding lower axle corner template 3, allowing the lower axle corner template 3 to move in sync with the upper axle corner template 2. Through the cooperation of these templates and the inner support assembly 4, a flexibly adjustable inner mold structure is formed, effectively adapting to the needs of precast tunnel construction and demolding, avoiding the problems of cumbersome operation and poor forming quality associated with traditional inner mold construction methods.

[0033] Specifically, the inner top formwork 1 is typically made of high-strength steel plate, usually in a flat shape to ensure a good fit to the shape of the immersed tunnel top. Alternatively, a composite material plate with some elasticity can be used instead of steel plate; this material can cushion the impact during construction to some extent. The inner top formwork 1 is fixed to the inner support assembly 4 by welding or bolting to ensure the stability of the connection. For example, in the construction of some small immersed tunnels, bolted connections facilitate the later replacement and maintenance of the inner top formwork 1; while in the construction of large immersed tunnels, welded connections provide more reliable support strength.

[0034] The upper axle corner template 2 has a bent structure, suitable for the shape of the upper axle corner of the immersed tube. It is generally made of aluminum alloy, which is lightweight and high-strength. Of course, stainless steel can also be used, as it has better corrosion resistance. The hinge between the upper axle corner template 2 and the inner top template 1 is connected by a pin, which allows the upper axle corner template 2 to rotate flexibly. Furthermore, grease can be applied to the pin to reduce friction during rotation and extend its service life.

[0035] The shape of the lower armpit corner template 3 is adapted to that of the upper armpit corner template 2, and it is also bent. It is usually made of cast steel, which has good rigidity. Alternatively, reinforced plastic material can be used, which is lightweight and easy to handle. The hinge method between the lower armpit corner template 3 and the upper armpit corner template 2 is similar to the hinge method between the upper armpit corner template 2 and the inner top template 1, both of which are connected by pins.

[0036] The inner support assembly 4 includes the main body of the gantry 41 and the support frame 44. The main body of the gantry 41 is generally welded from structural steel, with a frame shape and strong load-bearing capacity. Alternatively, the main body of the gantry 41 can be constructed from steel pipes, which have good toughness. The top of the main body of the gantry 41 is welded to the lower surface of the inner top template 1, providing stable support for the inner top template 1. The support frame 44 is usually made of channel steel, with a rod shape. It is fixed to the inside of the upper corner template 2, reinforcing the upper corner template 2. Angle steel can also be used to make the support frame 44; angle steel is relatively inexpensive and easy to process.

[0037] The inner support assembly 4 is equipped with a first telescopic drive component 5, used to drive the upper armpit corner template 2 to expand or contract. The first telescopic drive component 5 is typically a hydraulic cylinder, which has a large driving force. An electric actuator can also be used; electric actuators are simple to operate and offer high control precision. The first telescopic drive component 5 drives the upper armpit corner template 2 to rotate through its telescopic movement.

[0038] A second telescopic drive component 6 is provided between the lower axillary corner template 3 and the upper axillary corner template 2 to drive the lower axillary corner template 3 to expand or contract. The second telescopic drive component 6 can also be a hydraulic cylinder or an electric push rod. The lower axillary corner template 3 is moved by telescopic movement.

[0039] The inner support assembly 4 is equipped with a lifting drive component 7 at its bottom. The lifting drive component 7 forces the inner support assembly 4 and the inner top template 1 to move upward by lifting downward, and forces the support assembly and the inner top template 1 to move downward by retracting. The lifting drive component 7 is generally a jack, which has a simple structure and is easy to operate. A screw jack can also be used, which has a self-locking function to ensure the stability of the inner top template 1 after it is raised.

[0040] Reference Figure 2 and Figure 3 The inner support assembly 4 also includes a first inner push rod 42 and a first outer push rod 43. One end of the first outer push rod 43 is hinged to the telescopic end of the first telescopic drive member 5, and the other end is hinged to the support frame 44. The end of the first telescopic drive member 5 away from the first outer push rod is hinged to the support frame 44.

[0041] The first outer push rod 43 is provided with a first connection point 432. One end of the first inner push rod 42 is hinged to the first connection point 432 of the first outer push rod 43, and the other end is hinged to the gantry 41. The first outer push rod 43 is usually made of solid steel and has high strength. Hollow steel pipes can also be used to reduce its weight. The structure of the first inner push rod 42 is similar to that of the first outer push rod 43. When the first telescopic drive member 5 extends and drives the upper armpit corner template 2 to unfold and be in place, the first inner positioning hole 421 of the first inner push rod 42 is aligned with the first outer positioning hole 431 of the first outer push rod 43, and the first inner push rod 42 and the first outer push rod 43 are in a straight line. The first inner positioning hole 421 and the first outer positioning hole 431 are connected by a pin to achieve the locking purpose between the first inner push rod 42 and the first outer push rod 43, so as to form a support system between the gantry 41 and the support frame 44 and enhance the stability of the upper armpit corner template 2 after unfolding.

[0042] Reference Figure 2 and Figure 4 The inner support assembly 4 also includes a second inner push rod 46 and a second outer push rod 45. One end of the second outer push rod 45 is hinged to the telescopic end of the second telescopic drive member 6, and the other end is hinged to the support frame 44. The end of the second telescopic drive member 6 away from the second outer push rod is hinged to the support frame 44.

[0043] The second outer push rod 45 is provided with a second connection point 452. One end of the second inner push rod 46 is hinged to the second connection point 452 of the second outer push rod 45, and the other end is hinged to the inner side of the underarm corner template 3. The material and structure of the second outer push rod 45 and the second inner push rod 46 are similar to those of the first outer push rod 43 and the first inner push rod 42. When the second telescopic drive member 6 drives the underarm corner template 3 to unfold and be in place, the second inner positioning hole 461 of the second inner push rod 46 is aligned with the second outer positioning hole 451 of the second outer push rod 45, and the second inner push rod 46 and the second outer push rod 45 are in a straight line. The second inner positioning hole 461 and the second outer positioning hole 451 are connected by a pin to achieve the locking purpose between the second inner push rod 46 and the second outer push rod 45, so as to form a support system between the support frame 44 and the underarm corner template 3, and ensure the stability of the underarm corner template 3 after unfolding.

[0044] Reference Figure 5 A central walking passage 82 is connected to the front end of the inner top formwork 1, and a side walking passage 81 is connected to the front end of the upper armpit corner formwork 2. The side walking passage 81 moves synchronously with the upper armpit corner formwork 2. When the inner formwork of the immersed tunnel is unfolded, the side walking passage 81 unfolds along with the upper armpit corner formwork 2 and connects with the central walking passage 82 to form a working platform 8. The working platform 8 is used for the reinforcement binding work at the post-pouring strip location. The central walking passage 82 and the side walking passage 81 are generally welded from metal plates and the surface is covered with anti-slip material to ensure the safety of construction personnel.

[0045] The implementation principle of this embodiment is as follows: The modular design of the immersed tunnel inner formwork structure allows for flexible adjustment and coordination among various formwork components, greatly simplifying the assembly and disassembly process. The coordinated operation of the first telescopic drive component 5, the second telescopic drive component 6, and the lifting drive component 7 enables rapid and accurate unfolding and retraction of the inner formwork, improving construction efficiency. Simultaneously, the support system formed by the inner and outer top rods enhances the stability of the formwork after unfolding, ensuring the quality of the immersed tunnel forming. Furthermore, the working platform 8 formed by the channels on the inner top formwork 1 and the upper armpit corner formwork 2 facilitates the rebar tying work for the post-cast strip, further improving construction convenience and overall integrity. Compared to traditional inner formwork assembly methods, this embodiment overcomes problems such as error accumulation and difficulty in demolding, representing a significant improvement and contribution to existing technology.

[0046] Example 2 The immersed tunnel prefabrication construction method provided in this application includes the following steps: S1: Construct the outer bottom formwork, the outer formwork on both sides of the immersed tunnel segment, and the end formwork at both ends of the immersed tunnel segment. Then, pour the horizontal foundation section at the bottom of the immersed tunnel segment. The outer bottom formwork, outer formwork, and end formwork are generally made of high-strength precast concrete slabs. During construction, the formwork is hoisted to the designated position by a crane and fixed with bolts. When pouring the horizontal foundation section, concrete is transported to the construction site using a concrete mixer truck, and then pumped into the formwork for pouring.

[0047] S2: Construct the inner formwork structure for the immersed tunnel on the surface of the horizontal foundation section. Following the installation method of the inner formwork structure for the immersed tunnel described in the previous embodiment, install the inner top formwork 1, upper axle corner formwork 2, lower axle corner formwork 3, and inner support assembly 4, etc., in sequence.

[0048] S3: Activate the lifting drive component 7 to raise and position the inner support component 4 and the inner top template 1. Activate the first telescopic drive component 5, which extends to drive the upper armpit corner template 2 outwards and into position. Activate the second telescopic drive component 6, which extends to drive the lower armpit corner template 3 outwards and into position. The inner top template 1, upper armpit corner template 2, and lower armpit corner template 3 constitute the inner mold system for the immersed tube. During operation, the unfolding and raising of the templates are achieved by controlling the switches of the corresponding drive devices.

[0049] S4: Reference Figure 6An outer formwork structure 9 is constructed, comprising an outer formwork body 94, a lateral frame 91 located outside the outer formwork body 94, a pedestrian ladder 93 located outside the lateral frame 91, and a pedestrian passage 92 located on top of the lateral frame 91. The pedestrian ladder 93 extends from the bottom of the lateral frame 91 to the top of the lateral frame 91 and connects with the pedestrian passage 92. The outer formwork body 94 is typically made of plywood, which is low-cost and easy to process. Plastic formwork can also be used, as it is lightweight and can be reused multiple times. The lateral frame 91 is made of I-beams, providing reliable support for the outer formwork body 94. The pedestrian ladder 93 and the pedestrian passage 92 facilitate the passage and operation of construction personnel during the construction process.

[0050] In addition, the prefabricated outer formwork structure of the immersed tunnel also includes guide slides. Several traveling devices 95 are installed at the bottom of the lateral frame, spaced apart along the length of the lateral frame. The lateral frame moves on the guide slides via the traveling devices 95. The guide slides can be made of steel rails laid on the ground. The steel rails have high flatness and straightness, providing precise guidance for the traveling devices 95. The installation of the traveling devices 95 makes the movement of the outer formwork body more convenient and precise, replacing the traditional method of relying on large hoisting equipment or manual pushing, reducing construction costs and improving construction efficiency.

[0051] The traveling device 95 includes a mounting frame disposed inside the side frame, traveling wheels 956 disposed at the bottom of the mounting frame, and a driving component for driving the traveling wheels 956 to roll. The traveling wheels 956 are used to travel on guide rails. The mounting frame includes a transverse steel frame 951, a vertical inner cylinder 957, a vertical outer cylinder 952, a transverse guide rail 953, a slide block 954, and a receiving box 955. The transverse steel frame 951 is fixed inside the side frame, the vertical inner cylinder 957 is fixed at the transverse steel frame 951, the vertical outer cylinder 952 is slidably sleeved on the outside of the vertical inner cylinder 957, the transverse guide rail 953 is installed and fixed at the lower end of the vertical outer cylinder 952, the slide block 954 is transversely slidably connected to the lower part of the transverse guide rail 953, the receiving box 955 is fixed at the bottom of the slide block 954 and is arranged longitudinally, and a number of traveling wheels 956 are installed inside the receiving box 955 and are distributed longitudinally. A transverse hydraulic cylinder is installed at the slide block 954, with its piston rod facing outwards from the outer formwork body. The transverse hydraulic cylinder moves the slide block 954 laterally by pushing against the formwork body, thereby adjusting the lateral position of the traveling wheels 956. A vertical hydraulic cylinder is fixed in the vertical inner cylinder 957, with its piston rod connected to the vertical outer cylinder 952. The vertical hydraulic cylinder slides the outer cylinder 952 vertically by extending and retracting, thereby adjusting the vertical position of the traveling wheels 956. This mounting frame structure is ingeniously designed. Through the coordinated action of the transverse and vertical hydraulic cylinders, it can flexibly adjust the lateral and vertical positions of the traveling wheels 956, allowing the outer formwork body to make precise posture adjustments according to actual needs during movement, better adapting to different construction requirements.

[0052] The vertical wall sections on both sides and in the middle of the immersed tunnel segment are poured, and finally the horizontal top wall section at the top of the immersed tunnel segment is poured to form the immersed tunnel segment. A post-pouring strip is formed between adjacent immersed tunnel segments. The outer formwork structure 9 is erected in accordance with the installation method of the outer formwork structure 9 in the previous embodiment. When pouring the vertical wall sections and the horizontal top wall sections, concrete mixer trucks and pumping equipment are also used for concrete transportation and pouring.

[0053] S5: Tie the reinforcing bars at the post-cast strip between adjacent immersed tube segments, and finally carry out the post-cast strip pouring construction. When tying the reinforcing bars, the construction workers stand on the working platform 8 formed by the central walking passage 82 and the side walking passage 81 to operate, use a reinforcing bar bending machine and a reinforcing bar cutting machine to process and cut the reinforcing bars, and then tie the reinforcing bars firmly with wire.

[0054] Before the construction of the post-pouring strip, an inner formwork structure 10 for the post-pouring strip is erected at the construction location. The inner formwork structure 10 includes a middle template 101, two upper templates 102, two lower templates 103, and an inner support frame 108. The middle template 101 is set above the inner support frame 108. The two upper templates 102 are respectively hinged to both sides of the middle template 101. The two lower templates 103 correspond one-to-one with the two upper templates 102. The end of the upper template 102 away from the inner support frame 108 is hinged to the corresponding lower template 103. This connection method allows the upper templates 102 and the lower templates 103 to rotate relative to each other, which is convenient for unfolding and shrinking, thereby adapting to post-pouring strips of different sizes and shapes. The inner support frame 108 is equipped with a first adjusting drive component 104 and a second adjusting drive component 105. The first adjusting drive component 104 is used to drive the upper template 102 to expand or contract, and the second adjusting drive component 105 is used to drive the lower template 103 to expand or contract. These two drive components can precisely control the degree of template expansion to meet construction requirements. A lifting drive component 107 is provided at the bottom of the inner support frame 108. The lifting drive component 107 forces the inner support frame 108 and the intermediate template 101 to move upward by lifting downward, and forces the inner support frame 108 and the intermediate template 101 to move downward by contracting. This design allows for convenient adjustment of the template device height, enabling rapid positioning and dismantling.

[0055] Specifically, the intermediate formwork 101 is typically a large flat plate structure, made of either high-strength plastic sheet or aluminum alloy sheet. Plastic sheet is lightweight and corrosion-resistant, while aluminum alloy sheet is high-strength and less prone to deformation. In practical applications, plastic sheet is more suitable if the construction environment has high humidity; if higher strength is required for the formwork, aluminum alloy sheet is a better choice. The intermediate formwork 101 is fixed to the inner support frame 108 by welding or bolting to ensure a stable connection.

[0056] The upper template 102 and the lower template 103 have similar structures, both consisting of a plate and hinge components. The plate can also be made of plastic or aluminum alloy, and the hinge components are generally metal hinges, which offer good rotational performance and durability. One side of the upper template 102 is hinged to the middle template 101 via a metal hinge, and the other side is hinged to the lower template 103. This hinged structure allows for greater flexibility in the expansion and contraction of the template. For example, in the construction of some small post-pouring strips, the template rotates at a high frequency, and the metal hinges ensure stable operation over extended periods.

[0057] The first adjusting drive component 104 includes several first telescopic rods, which can be hydraulic or electric. Hydraulic telescopic rods have high thrust and good stability, making them suitable for large template devices; electric telescopic rods offer high control precision and convenient operation, making them suitable for small template devices. One end of each of the several first telescopic rods is hinged to the inner support frame 108 and converges on the upper side of the inner support frame 108, while the other end is hinged to the inner side of the upper template 102 and spaced along the contour of the upper template 102. This distribution allows the first telescopic rods to apply force evenly to the upper template 102, ensuring that the upper template 102 unfolds or retracts smoothly. For example, when a first telescopic rod extends, it pushes the upper template 102 to rotate outward around the hinge point with the intermediate template 101 until it abuts against the inner wall of the adjacent immersed tube segment.

[0058] The second adjustment drive component 105 includes several second telescopic rods, which can be hydraulic or electric telescopic rods. Their arrangement is similar to that of the first telescopic rods. One end of each of the second telescopic rods is hinged to the inner support frame 108 and converges at the lower side of the inner support frame 108. The other end is hinged to the inner side of the lower template 103 and spaced along the contour of the lower template 103. Through the extension and retraction of the second telescopic rods, the lower template 103 can be expanded or contracted, allowing it to accurately abut against the inner wall of adjacent immersed tube segments.

[0059] The lifting drive component 107 typically uses a jack or a hydraulic cylinder. Jacks are simple in structure and inexpensive, making them suitable for lifting small formwork devices; hydraulic cylinders, on the other hand, have greater lifting force and a longer stroke, making them more suitable for large formwork devices. The lifting drive component 107 is installed at the bottom of the inner support frame 108. When the formwork device needs to be raised, the lifting drive component 107 pushes downwards to lift the ground. According to the principle of action and reaction, the inner support frame 108 and the intermediate formwork 101 will move upwards. When the formwork device needs to be lowered, the lifting drive component 107 retracts, and the formwork device descends accordingly.

[0060] During the construction of the post-pouring strip between adjacent immersed tunnel segments, the lifting drive 107 drives the inner support frame 108 and the intermediate template 101 to rise and be in place. The first telescopic drive 5 extends to drive the upper template 102 to unfold outward and abut against the inner wall of the adjacent immersed tunnel segment. The second adjusting drive 105 extends to drive the lower template 103 to unfold outward and abut against the inner wall of the two adjacent immersed tunnel segments. At this time, the gap between the intermediate template 101, the upper template 102, and the lower template 103 and the two adjacent immersed tunnel segments forms the post-pouring strip pouring area. This combination logic enables the template device to quickly and accurately form the required pouring space, improving construction efficiency and forming accuracy.

[0061] Specifically, the internal support frame 108 is the supporting structure of the entire formwork assembly. It is typically constructed by welding steel pipes to form a frame structure. The steel pipes possess high strength and stability, capable of bearing the weight of the formwork and concrete. The design of the internal support frame 108 must be rationally planned according to the size and weight of the formwork to ensure it can provide sufficient support.

[0062] The workbench 106 is located on the upper side of the inner support frame 108. The workbench 106 is generally made of steel plate, and the surface of the steel plate can be treated with anti-slip coating, such as spraying anti-slip paint or setting anti-slip texture, to ensure the safety of construction personnel. The workbench 106 provides construction personnel with an operating space to facilitate their installation, adjustment and inspection of the formwork.

[0063] The step ladder is installed on the inner support frame 108. The inclined upper end of the step ladder connects to the workbench 106, and the inclined lower end extends inward toward the inner side of the inner support frame 108. The steps of the step ladder can be made of checkered steel plate to increase friction and prevent people from slipping. Construction workers can easily go up and down the workbench 106 using the step ladder.

[0064] Pulley 109 is installed at the bottom of the inner support frame 108. Pulley 109 can be a caster wheel, which has the characteristic of flexible steering, facilitating the movement and positioning of the formwork device. During construction, by pushing the formwork device, pulley 109 can easily move the entire device around the construction site.

[0065] Sealing steel sheets are installed on the outer sides of both the upper template 102 and the lower template 103. These sealing steel sheets are typically made of stainless steel, which offers excellent corrosion resistance and sealing performance. When the upper template 102 and the lower template 103 are unfolded, the sealing steel sheets abut against the inner walls of adjacent immersed tunnel sections, providing a seal and preventing concrete leakage. An abutment is installed at both the upper template 102 and the lower template 103. This abutment can be a spring or a bolt. Springs are elastic and can automatically adjust the abutment force; bolts provide a stable abutment force through tightening. The abutment forces the sealing steel sheets against the inner walls of the immersed tunnel sections, ensuring a tight seal.

[0066] During the post-cast strip construction, the same concrete as the immersed tube segment is used for casting to ensure the overall strength and stability.

[0067] The implementation principle of this embodiment is as follows: The immersed tunnel prefabrication construction method in this embodiment, through a reasonable arrangement of steps, utilizes the inner formwork structure and outer formwork structure 9 of the immersed tunnel in the previous embodiment to achieve efficient and precise prefabrication of the immersed tunnel. Each step is closely linked, from formwork erection to concrete pouring and post-pouring strip treatment, with each step having a clear operation and purpose. This construction method avoids the problems of cumbersome operations and long construction cycles in traditional construction methods, improves construction quality and efficiency, and significantly improves and enhances immersed tunnel construction technology.

[0068] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A formwork structure for an immersed tunnel, characterized in that, The system includes an inner top template (1), two upper axillary corner templates (2), two lower axillary corner templates (3), and an inner support assembly (4). The inner top template (1) is positioned above the inner support assembly (4). The two upper axillary corner templates (2) are respectively hinged to both sides of the inner top template (1). The two lower axillary corner templates (3) correspond one-to-one with the two upper axillary corner templates (2). The end of the upper axillary corner template (2) furthest from the inner support assembly (4) is hinged to the corresponding lower axillary corner template (3). The inner support assembly (4) is provided with a first A telescopic drive (5) is used to drive the upper axillary corner template (2) to expand or contract; a second telescopic drive (6) is provided between the lower axillary corner template (3) and the upper axillary corner template (2) to drive the lower axillary corner template (3) to expand or contract; a lifting drive (7) is provided at the bottom of the inner support assembly (4), the lifting drive (7) forces the inner support assembly (4) and the inner top template (1) to move upward by lifting downward, and forces the inner support assembly (4) and the inner top template (1) to move downward by contracting; During the precast construction of the immersed tube, the lifting drive (7) drives the inner support assembly (4) and the inner top template (1) to rise and be in place. The first telescopic drive (5) extends to drive the upper armpit corner template (2) to unfold and be in place. The second telescopic drive (6) extends to drive the lower armpit corner template (3) to unfold and be in place. The inner top template (1), the upper armpit corner template (2) and the lower armpit corner template (3) constitute the immersed tube inner mold system. After the precast tunnel is completed, the second telescopic drive (6) retracts to drive the lower armpit corner template (3) to retract inward and demold; the first telescopic drive (5) retracts to drive the upper armpit corner template (2) to retract inward and demold; the lifting drive (7) retracts to drive the inner top template (1) to descend and demold.

2. The immersed tunnel inner formwork structure according to claim 1, characterized in that: The inner support assembly (4) includes a gantry (41) body and a support frame (44). The top of the gantry (41) body is fixed to the lower surface of the inner top template (1) and provides support for the inner top template (1). The support frame (44) is fixed to the inner side of the upper armpit corner template (2) and plays a reinforcing role.

3. The immersed tunnel inner formwork structure according to claim 1, characterized in that: The lifting drive component (7) includes a lifting hydraulic cylinder located at the lower part of the gantry (41).

4. The immersed tunnel inner formwork structure according to claim 1, characterized in that: The inner support assembly (4) further includes a first inner push rod (42) and a first outer push rod (43). One end of the first outer push rod (43) is hinged to the telescopic end of the first telescopic drive member (5), and the other end is hinged to the support frame (44). The first outer push rod (43) is provided with a first connection point (432). One end of the first inner push rod (42) is hinged to the first connection point (432) of the first outer push rod (43), and the other end is hinged to the gantry (41). The first outer push rod (43) is provided with a first outer positioning hole (431). The first inner push rod (42) is provided with a first inner positioning hole (431). Positioning hole (421): When the upper armpit corner template (2) is fully extended and positioned under the drive of the first telescopic drive member (5), the first inner positioning hole (421) of the first inner top rod (42) is aligned with the first outer positioning hole (431) of the first outer top rod (43), and the first inner top rod (42) and the first outer top rod (43) are in a straight line. The first inner positioning hole (421) and the first outer positioning hole (431) are connected by a pin to achieve the locking purpose between the first inner top rod (42) and the first outer top rod (43), so as to form a support system between the gantry (41) and the support frame (44).

5. The immersed tunnel inner formwork structure according to claim 1, characterized in that: The inner support assembly (4) further includes a second inner push rod (46) and a second outer push rod (45). One end of the second outer push rod (45) is hinged to the telescopic end of the second telescopic drive member (6), and the other end is hinged to the support frame (44). The second outer push rod (45) is provided with a second connection point (452). One end of the second inner push rod (46) is hinged to the second connection point (452) of the second outer push rod (45), and the other end is hinged to the inner side of the underarm corner template (3). The second outer push rod (45) is provided with a second outer positioning hole (451). The second inner push rod (46) is provided with a second outer positioning hole (451). When the underarm corner template (3) is fully extended and positioned under the drive of the second telescopic drive member (6), the second inner positioning hole (461) of the second inner push rod (46) is aligned with the second outer positioning hole (451) of the second outer push rod (45), and the second inner push rod (46) and the second outer push rod (45) are in a straight line. The second inner positioning hole (461) and the second outer positioning hole (451) are connected by a pin to achieve the purpose of locking the second inner push rod (46) and the second outer push rod (45) to form a support system between the support frame (44) and the underarm corner template (3).

6. The immersed tunnel inner formwork structure according to claim 1, characterized in that: A central walking channel (82) is connected to the front end of the inner top formwork (1), and a side walking channel (81) is connected to the front end of the upper armpit corner formwork (2). The side walking channel (81) moves synchronously with the upper armpit corner formwork (2). When the inner formwork of the immersed tunnel is unfolded, the side walking channel (81) unfolds with the upper armpit corner formwork (2) and connects with the central walking channel (82) to form a working platform (8). The working platform (8) is used for the reinforcement binding work at the post-pouring strip position.

7. A precast immersed tunnel construction method as described in claim 1, employing an internal formwork structure for the immersed tunnel, comprising the following steps: S1: Construct the outer bottom template, the outer templates on both sides of the immersed tunnel segment, and the end templates at both ends of the immersed tunnel segment, and then pour the horizontal foundation section at the bottom of the immersed tunnel segment. S2: Construct the inner formwork structure for the immersed tube on the surface of the horizontal foundation section; S3: Start the lifting drive (7) to drive the inner support component (4) and the inner top template (1) to rise and be in place. Start the first telescopic drive (5) to extend and drive the upper armpit corner template (2) to unfold and be in place. Start the second telescopic drive (6) to extend and drive the lower armpit corner template (3) to unfold and be in place. The inner top template (1), the upper armpit corner template (2) and the lower armpit corner template (3) constitute the inner mold system of the immersed tube. S4: Build the external formwork structure (9), pour the vertical wall sections on both sides and in the middle of the immersed tube segment, and finally pour the horizontal top wall section at the top of the immersed tube segment to form the immersed tube segment. A post-pouring strip is formed between adjacent immersed tube segments. S5: Tie reinforcing bars at the post-cast strip between adjacent immersed tube segments, and finally carry out the post-cast strip pouring construction.

8. The immersed tunnel inner formwork structure according to claim 7, characterized in that: The outer template structure includes an outer template body, a lateral frame located outside the outer template body, a pedestrian ladder located outside the lateral frame, and a pedestrian passage located on the top of the lateral frame. The pedestrian ladder extends from the bottom of the lateral frame to the top of the lateral frame and connects with the pedestrian passage.

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