High-strength pouring formwork for tunnel ventilation shaft and construction method of high-strength pouring formwork

Abstract

The invention provides a high-strength pouring formwork for a tunnel ventilation shaft and a construction method of the high-strength pouring formwork, and relates to the technical field of tunnel ventilation shaft construction.The high-strength pouring formwork comprises a vertically-arranged main barrel and a push-pull mechanism arranged on the main barrel; a driving mechanism a and a driving mechanism b are arranged in the main cylinder body, and a sub-template a and a sub-template b are further arranged on the periphery of the main cylinder body; wherein the sub-template a is attached to the push-pull frame, the power output end of the driving mechanism a is connected with the push-pull frame, and the driving mechanism a is used for driving the sub-template a to be close to or away from the main cylinder body; the power output end of the driving mechanism b is connected with the sub-template b and is used for driving the sub-template b to be close to or far away from the main cylinder body; at least six equidistantly distributed templates a and sub-templates b are spliced to form a cylinder structure, and at least one annular groove is formed in the surface of the cylinder structure, so that the problems that the overall stability is reduced and the service life is shortened due to the fact that an existing ventilation shaft structure is subjected to non-uniform pressure of a surrounding soil body are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel ventilation shaft construction, and in particular to a high-strength casting template for a tunnel ventilation shaft and a construction method thereof. Background Art

[0002] Tunnel ventilation shafts are critical structures in tunnel construction, introducing fresh air, exhausting harmful gases and smoke, regulating internal temperature and humidity, and ensuring smoke escape in emergencies such as fires. The cast-in-place reinforced concrete structure of the ventilation shaft is typically constructed with a circular cross-section, internally equipped with vertical main reinforcement, circumferential stirrups, and a transverse support system to meet compression, bending, and seepage requirements. The structure must be embedded in the surrounding rock and soil, sharing loads with the surrounding rock, while also adapting to the complex underground environment.

[0003] Cast-in-place ventilation shaft structures are significantly affected by the non-uniform pressure of the surrounding soil. For example, at the junction of soft soil and hard rock, differences in the soil's elastic modulus can cause asymmetric lateral pressure on the shaft wall, leading to circumferential stress concentration. Furthermore, soil displacement caused by seasonal frost heave, seismic liquefaction, or construction disturbances can alter the original stress distribution, leading to differential settlement or localized deformation of the shaft wall, further weakening overall stability. This shortens the actual lifespan of the structure compared to its theoretical value and significantly increases operation and maintenance costs. Summary of the Invention

[0004] An embodiment of the present invention provides a high-strength casting template for a tunnel ventilation shaft and a construction method thereof, which are used to solve the problem that the existing ventilation shaft structure is subjected to uneven pressure from the surrounding soil and has reduced overall stability and shortened service life.

[0005] In view of the above problems, the technical solution proposed by the present invention is: A high-strength casting template for a tunnel ventilation shaft, comprising: A main cylinder disposed vertically, and a push-pull mechanism disposed on the main cylinder; The push-pull mechanism includes an upper fixing member and a lower fixing member fixed at both ends of the main cylinder, wherein at least six push-pull frames distributed at equal intervals are hinged between the upper fixing member and the lower fixing member, and a tension spring is provided between the push-pull frame and the main cylinder; The main cylinder is provided with a driving mechanism a and a driving mechanism b, and the outer periphery of the main cylinder is provided with a sub-template a and a sub-template b; Among them, the sub-template a is attached to the push-pull frame, and the power output end of the driving mechanism a is connected to the push-pull frame to drive the sub-template a closer to or away from the main cylinder; The power output end of the driving mechanism b is connected to the sub-template b, and is used to drive the sub-template b toward or away from the main cylinder; At least six equally spaced templates a and sub-templates b are spliced ​​to form a cylindrical structure, and the surface of the cylindrical structure has at least one annular groove.

[0006] In order to better implement the technical solution of the present invention, the following technical measures are also adopted.

[0007] Furthermore, the main cylinder body has a slide groove and a through hole, wherein the position and number of the slide groove correspond to the position and number of the push-pull frame, the through hole is arranged between two adjacent push-pull frames, and the bottom wall of the slide groove has a guide groove connected to the main cylinder body.

[0008] Furthermore, the upper fixing member includes an upper fixing seat and at least six upper hinge supports evenly distributed along the axial direction of the upper fixing seat, one end of the upper hinge block is hinged on the upper hinge support, and the other end of the upper hinge block is hinged to one end of the push-pull frame.

[0009] Furthermore, the lower fixing member includes a lower fixing seat and at least six lower hinge supports evenly distributed along the axial direction of the lower fixing seat, one end of the lower hinge block is hinged to the lower hinge support, and the other end of the lower hinge block is hinged to the other end of the push-pull frame.

[0010] Furthermore, the push-pull mechanism also includes an inclined slide, which is fixedly arranged on the push-pull frame, with the inclined side of the inclined slide facing the main cylinder, and the non-inclined side of the inclined slide connected to the non-casting surface of the sub-template a through a push-pull rod.

[0011] Furthermore, the driving mechanism a includes a driving motor a, which is arranged on a lower fixed seat, and its output shaft is connected to a screw rod a arranged inside the main cylinder. A connecting limit plate that can move inside the main cylinder is provided inside the main cylinder. The connecting limit plate passes through the guide groove and is connected to the non-inclined side of the inclined slider arranged in the slide groove. The screw rod a passes through the connecting limit plate and is threadedly connected to it.

[0012] Furthermore, a limit plate is fixedly provided inside the main cylinder. The limit plate has a hole for the screw rod a to pass through, and a bearing is provided inside the hole. The screw rod a passes through the bearing and is connected to the hole.

[0013] Furthermore, the driving mechanism b includes a threaded sleeve, wherein the threaded sleeve is fixedly arranged on the non-casting surface side of the sub-template b, and its internal thread is connected to one end of the screw rod b, and the other end of the screw rod b extends through the through hole to the interior and is connected to the output shaft of the driving motor b fixed on the inner wall of the main cylinder.

[0014] Furthermore, the sub-template a includes an arc-shaped plate a having an inner concave portion a on its surface, and the sub-template b includes an arc-shaped plate b having an inner concave portion b on its surface, and the annular groove is formed by splicing the inner concave portion a and the inner concave portion b.

[0015] A high-strength tunnel ventilation shaft construction method comprises the following steps: S1, remove the surface soil or loose rock layer and excavate the wellhead section from the ground downwards; S2, a locking ring is installed circumferentially on the inner wall of the wellhead section, and a molded reinforced concrete structure is used to form a single-layer support for the wellhead section; S3, along the longitudinal direction of the ventilation shaft from the wellhead to the well bottom, the construction is carried out in sections. After the excavation of a section is completed, a steel structure is set on the well wall. At the same time, the casting template with the annular convex reinforcement forming structure is hoisted into the well using hoisting equipment; S4, after the casting formwork is completed in the ventilation shaft, concrete is poured into the formwork; S5, after the concrete structure strength reaches the required level, the casting formwork is separated from the concrete structure and lifted out of the ventilation shaft; S6, repeat the above steps S3 to S5 until the ventilation shaft construction is completed.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. By utilizing the annular groove of the casting template, a number of annular ribs can be formed on the inner wall of the ventilation shaft during the casting process. The annular ribs increase the geometric stiffness of the shaft wall section, creating an effect similar to "stiffening ribs", which can effectively disperse the non-uniform lateral pressure transmitted by the surrounding soil. Especially in soft and hard alternating strata, the ribs can suppress the annular cracking or longitudinal shear deformation of the shaft wall caused by differential soil pressure, thereby improving the compressive bearing capacity.

[0017] 2. It can automatically support and dismantle the formwork, which simplifies the existing ventilation shaft formwork and dismantling steps, reduces the use of manpower, and improves construction efficiency.

[0018] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are specifically listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic structural diagram of a casting template disclosed in an embodiment of the present invention; Figure 2 A schematic diagram of the structure of the sub-template a and sub-template b disclosed in an embodiment of the present invention; Figure 3 This is a partial enlarged structural diagram of the casting formwork (near the upper fixing part); Figure 4 for Figure 3 Schematic diagram of the structure after removing sub-template a and sub-template b; Figure 5 for Figure 4 A in the middle is an enlarged structural diagram; Figure 6 This is a partial enlarged structural diagram of the casting formwork (sub-formwork a and sub-formwork b are removed, near the lower fixing part); Figure 7 A schematic cross-sectional view of a casting template disclosed in an embodiment of the present invention; Figure 8 A schematic diagram of the top view of the casting template disclosed in an embodiment of the present invention; Figure 9 This is a schematic flow chart of a high-strength tunnel ventilation shaft construction method disclosed in an embodiment of the present invention.

[0020] Reference numerals: 1, sub-template a; 11, curved plate a; 12, recessed portion a; 2, sub-template b; 21, curved plate b; 22, recessed portion b; 3, annular groove; 4, main cylinder; 41, slide groove; 42, guide groove; 43, through hole; 5, push-pull mechanism; 51, upper fixing member; 511, upper fixing seat; 512, upper hinge support; 513, upper hinge block; 52, lower fixing member; 521, lower fixing seat ; 522. Lower hinge support; 523. Lower hinge block; 53. Push-pull frame; 54. Inclined slide; 55. Push-pull rod; 6. Driving mechanism a; 61. Driving motor a; 62. Screw a; 63. Limiting plate; 64. Connecting limit plate; 65. Inclined slide; 7. Driving mechanism b; 71. Driving motor b; 72. Screw b; 73. Threaded sleeve; 8. Accommodating area; 9. Lifting ring a; 10. Lifting ring b. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0022] Figure 1 A schematic structural diagram of a casting template disclosed in an embodiment of the present invention is shown, which includes a main structure part and a template part connected to the main structure.

[0023] Among them, the template part is spliced ​​by the staggered sub-templates a1 and b2. In order to improve the sealing of the joint between the sub-templates a1 and b2, a rubber sealing layer is also provided at the joint between the sub-templates a1 and b2.

[0024] Among them, the forms of the template part are as follows: 1. Contraction state: This state is used to move the position of the casting template, such as lifting the casting template from the outside into the ventilation shaft, or lifting the casting template from the ventilation shaft to the outside, or adjusting the depth of the casting template in the ventilation shaft.

[0025] Figure 8A schematic diagram of the top structure of the casting template disclosed in an embodiment of the present invention is shown. When the casting template is in the expanded state, an accommodating area 8 is formed therein (between the sub-template a1, the sub-template b2 and the main cylinder 4). When shrinking, the sub-template b2 retracts into the accommodating area 8. During the retraction process, the sub-template b2 occupies a part of the space in the accommodating area 8 and then abuts against each other to wrap the sub-template b2 inside.

[0026] The above shrinkage process can separate the sub-template a1 and sub-template b2 from the poured concrete structure, so as to facilitate the movement of the pouring template. At the same time, in order to facilitate demoulding, the pouring surface of the sub-template a1 and sub-template b2 (the surface in contact with the concrete, Figure 8 Taking the direction in the figure as an example, the casting surface of sub-template a1 and sub-template b2 is located on the outside, and the non-casting surface is located on the inside) the mold release agent is applied. This adopts the existing technology and will not be repeated here.

[0027] 2. Expanded state, such as Figure 1 and 8 As shown, in this state, the slow-setting soil structure used for casting the ventilation shaft, in this state, the cross-sectional shape of the template formed by the staggered sub-template a1 and sub-template b2 is circular. During the casting process, the casting operation can be carried out after the bottom of the casting template is supported and sealed and the position of the casting template is fixed.

[0028] The above-mentioned fixed casting formwork position can adopt existing technologies, such as rigid support rod fixation, triangular tie rod support method, etc. The above two examples are only two of the existing technologies adopted. The position of the casting formwork can be fixed by the methods of the above two examples or by using a variety of combinations to fix the position of the casting formwork.

[0029] The above-mentioned unfolding process includes: driving the sub-template a1 away from the main cylinder 4 to unfold, and then driving the sub-template b2 away from the main cylinder 4 to unfold. During the unfolding process of the sub-template a1, a gap is formed between the sub-templates a1. After the sub-template b2 is fully unfolded, it is spliced ​​together with the sub-template a1 to form an integral template. At the same time, in order to facilitate the splicing of the sub-template a1 and the sub-template b2, mutually matching chamfers are formed on the edges of the sub-template a1 and the sub-template b2.

[0030] Figure 2 The schematic diagram of the structure of the sub-template a1 and the sub-template b2 disclosed in the embodiment of the present invention is shown. It can be seen that the sub-template a1 includes a curved plate a11 with an inner concave portion a12 on its surface, and the sub-template b2 includes a curved plate b21 with an inner concave portion b22 on its surface. Figure 1As shown, after the above-mentioned unfolding state is completed, the inner concave portion a12 and the inner concave portion b22 are spliced ​​together to form an annular groove 3, which is used to form an annular rib of the ventilation shaft, thereby increasing the geometric stiffness of the shaft wall section and dispersing the non-uniform lateral pressure transmitted by the surrounding soil.

[0031] Figures 3 to 7 The structure of the casting template is shown. In order to drive the sub-template a1, a main cylinder 4 is vertically arranged. At the same time, a push-pull mechanism 5 connected to the sub-template a1 and a driving mechanism a6 for driving the push-pull mechanism 5 are provided on the main cylinder 4.

[0032] like Figures 3-5 As shown, the push-pull mechanism 5 includes an upper fixing member 51 and a lower fixing member 52 fixed at both ends of the main cylinder 4, wherein at least six push-pull frames 53 distributed at equal intervals are hinged between the upper fixing member 51 and the lower fixing member 52, and a tension spring is arranged between the push-pull frame 53 and the main cylinder 4.

[0033] Next, the structure required for driving the sub-template a1 will be described.

[0034] Figure 3 Shows the structure of the upper fixing member 51, Figure 6 The structure of the lower fixing member 52 is shown. It can be seen that the structures of the upper fixing member 51 and the lower fixing member 52 are arranged in mirror symmetry, wherein the upper fixing member 51 includes an upper fixing seat 511 and at least six upper hinge supports 512 uniformly distributed axially along the upper fixing seat 511, one end of the upper hinge block 513 is hinged on the upper hinge support 512, and the other end of the upper hinge block 513 is hinged to one end of the push-pull frame 53, the lower fixing member 52 includes a lower fixing seat 521 and at least six lower hinge supports 522 uniformly distributed axially along the lower fixing seat 521, one end of the lower hinge block 523 is hinged under the lower hinge support 522, and the other end of the lower hinge block 523 is hinged to the other end of the push-pull frame 53.

[0035] In order to realize the driving sub-template a1, a slide groove 41 is provided on the main cylinder 4, wherein the position and number of the slide groove 41 correspond to the position and number of the push-pull frame 53, and the bottom wall of the slide groove 41 has a guide groove 42 connected to the main cylinder 4, and the driving mechanism a6 includes a driving motor a61, which is arranged on the lower fixed seat 521, and its output shaft is connected to the screw rod a62 arranged inside the main cylinder 4, and the main cylinder 4 is provided with a connecting limit plate 64 that can move inside the main cylinder 4. The connecting limit plate 64 passes through the guide groove 42 and is connected to the non-inclined side of the inclined slider 65 arranged in the slide groove 41, and the screw rod a62 passes through the connecting limit plate 64 and is threadedly connected to it. In order to maintain the stable operation of the screw rod, a limit plate 63 is also fixed inside the main cylinder 4. The limit plate 63 has a hole for the screw rod a62 to pass through, and a bearing is provided therein. The screw rod a62 passes through the bearing and is connected to it.

[0036] Figure 5 The structure of the most critical driving part is shown. Specifically, the push-pull mechanism 5 also includes an inclined slide 54, which is fixed on the push-pull frame 53. The inclined side of the inclined slide 54 faces the main cylinder 4, and the non-inclined side of the inclined slide 54 is connected to the non-casting surface of the sub-template a1 through a push-pull rod 55.

[0037] Next, the process of driving the sub-template a1 to move is described.

[0038] Since the output shaft of the driving motor a61 is connected to the screw a62, and the screw a62 is threadedly connected to the connecting limit plate 64, under the drive of the driving motor a61, the connecting limit plate 64 can reciprocate along the axial direction of the screw a62. In this process, the connecting limit plate 64 drives the inclined slider 65 to reciprocate in the slide groove 41. Figure 5 As shown, the inclined surface of the inclined slider 65 is in conflict with the inclined surface of the inclined slide 54. During the movement of the limit plate 64 driven by the screw rod a62, the inclined slider 65 changes its relative position with the inclined slide 54. During this process, the inclined slide 54 is pushed away from the main cylinder 4 or close to the main cylinder 4. The sub-template a1 connected to it through the push-pull rod 55 completes the expansion or contraction action during this process. During the process of the inclined slide 54 being pushed away from the main cylinder 4, the tension spring is stretched to store elastic potential energy. When the inclined slider 65 changes its position again so that the inclined slide 54 has a tendency to move in the opposite direction, the tension spring releases the elastic potential energy to pull the push-pull frame 53 toward the main cylinder 4.

[0039] The above-mentioned driving mechanism b7 can also be replaced with a structure equivalent to the driving mechanism a6. After being replaced with a structure equivalent to the driving mechanism a6, the driving mechanism a6 includes a driving motor a61, a screw rod a62, and a threaded sleeve 73a, wherein the threaded sleeve 73a is fixedly set on the non-casting surface of the sub-template a1, and the driving motor a61 is set inside the main cylinder 4, and its position is staggered with the driving motor b71 to avoid stress concentration. The driving motor b71 is threadedly connected to the threaded sleeve 73a through the screw rod a62 connected to its output shaft, and thereby drives the sub-template a1 close to or away from the main cylinder 4.

[0040] When the above replacement structure is adopted, at least two replacement structures need to be provided in the same longitudinal direction of the main cylinder 4 to achieve the action of expansion or contraction.

[0041] Figure 7A schematic diagram of the cross-sectional structure of the casting template disclosed in an embodiment of the present invention is shown. It can be seen that the driving mechanism b7 includes a threaded sleeve 73, wherein the threaded sleeve 73 is fixedly arranged on the non-casting surface side of the sub-template b2, and its internal thread is connected to one end of the screw rod b72, and the other end of the screw rod b72 extends through the through hole 43 to the inside and is connected to the output shaft of the driving motor b71 fixed on the inner wall of the main cylinder 4. The through hole 43 is arranged between two adjacent push-pull frames 53, and the position and number of the through holes 43 correspond to the position and number of the sub-template b2.

[0042] Next, the process of driving the sub-template b2 to move is described.

[0043] The motor b71 drives the screw rod b72 to rotate, and the screw rod b72 extends into or out of the threaded sleeve 73. During this process, the sub-template b2 approaches or moves away from the main cylinder 4, and the sub-template b2 completes the expansion or contraction action during this process.

[0044] It should be noted that the drive motor a61 and the drive motor b71 are connected to a driver and a controller for controlling their operation, which are used to control the drive motor a61 and the drive motor b71. Since the existing technology is adopted, the working principle of controlling the drive motor a61 and the drive motor b71 will not be repeated here.

[0045] Another thing to note is that, Figure 7 As shown, in the same longitudinal direction, there are at least two push-pull rods 55 connected to the sub-template a1, and the same number of slide grooves 41, guide grooves 42, and connecting limit plates 64 and inclined sliders 65 match it. In the same longitudinal direction, there are at least two driving mechanisms b7 connected to the sub-template b2.

[0046] The above-mentioned driving mechanism a6 and driving mechanism b7 can also be replaced by a hydraulic rod driving structure or an electric push rod driving structure. After the output shafts of the hydraulic rod driving structure or the electric push rod driving structure are respectively connected to the non-casting surfaces of the sub-template a1 and the sub-template b2, the expansion or contraction of the sub-template a1 and the sub-template b2 can be completed by the extension and contraction of the hydraulic rod driving structure or the electric push rod driving structure.

[0047] Through the above settings, the sub-template a1 and the sub-template b2 are driven to complete the contraction and expansion actions.

[0048] Figure 9 The high-strength tunnel ventilation shaft construction method disclosed in an embodiment of the present invention includes the following steps: S1, remove the surface soil or loose rock layer and excavate the wellhead section from the ground downwards.

[0049] S2, a locking ring is installed circumferentially on the inner wall of the wellhead section, and a molded reinforced concrete structure is used to form a single-layer support for the wellhead section.

[0050] S3, the construction is carried out in sections along the longitudinal direction of the ventilation shaft from the wellhead to the bottom of the shaft. After completing the excavation of a section, a steel structure is set on the shaft wall. At the same time, the casting template with an annular convex reinforcement forming structure is hoisted into the shaft using lifting equipment.

[0051] The annular rib forming structure is an annular groove 3 of the casting template. The number of annular grooves 3 can be specifically set according to the geology of the construction area. For example, multiple groups of sub-templates a1 and sub-templates b2 with different numbers of concave structures are set. Using sub-templates a1 and sub-templates b2 with a larger number of concave structures can form a larger number of annular ribs, while using sub-templates a1 and sub-templates b2 with a smaller number of concave structures can form a smaller number of annular ribs. An example is as follows: When a ventilation well passes through alternating soft and hard strata, differences in the elastic modulus of the soil cause the wellbore to be subjected to asymmetric lateral pressure. By increasing the number of annular ribs, stress concentration can be dispersed through multiple ribs, suppressing the expansion of circumferential cracks and improving the shear resistance of the wellbore.

[0052] When the ventilation shaft passes through a homogeneous hard rock or dense gravel layer, the lateral pressure distribution of the soil is uniform and the deformation is small. In this case, the number of annular ribs can be reduced, and only ribs at the basic spacing need to be set to meet the conventional compressive strength requirements.

[0053] In addition, sub-forms a1 and b2 without concave structures can also be provided. In this case, the workload of tying steel bars can be reduced during the pouring process, thereby improving the efficiency of the construction.

[0054] S4: After the casting formwork is completed in the ventilation shaft, concrete is poured into the formwork.

[0055] The above-mentioned supporting process includes unfolding the sub-formwork a1 and the sub-formwork b2, and sealing the bottom of the casting formwork and fixing the position of the casting formwork.

[0056] In another method of fixing the position of the casting formwork, the following structure is adopted, at least two lifting rings a9 are set on the upper fixing seat 511, and at least two lifting rings b10 are set on the lower fixing seat 521. The upper part of the casting formwork is fixed by the lifting ring a9, such as using a lifting tool for fixation, and the lower part of the casting formwork is fixed by the lifting ring b10, such as a pile or other structure. In this way, the casting formwork needs to be fixed in a rigid fixing manner. After the fixation is completed, it is only necessary to seal the bottom of the casting formwork to carry out the casting operation. Of course, other fixing methods in the prior art can also be applied to this method.

[0057] Lifting ring a9 is also used to connect lifting equipment to casting formwork.

[0058] S5: After the concrete structure strength reaches the required level, separate the casting formwork from the concrete structure and lift it away from the ventilation shaft.

[0059] After the concrete structure strength reaches the requirement, the driving mechanism a6 and the driving mechanism b7 are used to drive the sub-forms a1 and b2 to separate from the concrete structure. After the shrinkage action is completed, the casting structure can be moved to the next casting location or moved out of the ventilation shaft to the outside.

[0060] It should be noted that after the driving mechanism a6 changes the position of the inclined slider 65, the sub-form a1 moves toward the main cylinder 4 under the pull of the tension spring, thereby completing the separation action from the concrete structure.

[0061] S6, repeat the above steps S3 to S5 until the ventilation shaft construction is completed.

[0062] It should be noted that the specific models and specifications of the drive motor a61 and the drive motor b71 need to be selected and determined according to the actual specifications of the device, and the specific selection calculation method adopts the existing technology in this field, so it will not be described in detail.

[0063] The power supply and principle of the drive motor a61 and the drive motor b71 are clear to those skilled in the art and will not be described in detail here.

[0064] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A high-strength casting template for tunnel ventilation shaft, characterized in that: include: A main cylinder disposed vertically, and a push-pull mechanism disposed on the main cylinder; The push-pull mechanism includes an upper fixing member and a lower fixing member fixed at both ends of the main cylinder, wherein at least six push-pull frames distributed at equal intervals are hinged between the upper fixing member and the lower fixing member, and a tension spring is provided between the push-pull frame and the main cylinder; The main cylinder is provided with a driving mechanism a and a driving mechanism b, and the outer periphery of the main cylinder is provided with a sub-template a and a sub-template b; Among them, the sub-template a is attached to the push-pull frame, and the power output end of the driving mechanism a is connected to the push-pull frame to drive the sub-template a closer to or away from the main cylinder; The power output end of the driving mechanism b is connected to the sub-template b, and is used to drive the sub-template b toward or away from the main cylinder; At least six equally spaced templates a and sub-templates b are spliced ​​to form a cylindrical structure, and the surface of the cylindrical structure has at least one annular groove.

2. The pouring formwork according to claim 1, characterized in that: The main cylinder body is provided with a slide groove and a through hole, wherein the position and number of the slide groove correspond to the position and number of the push-pull frame, the through hole is arranged between two adjacent push-pull frames, and the bottom wall of the slide groove has a guide groove connected to the main cylinder body.

3. The pouring formwork according to claim 2, characterized in that: The upper fixing member includes an upper fixing seat and at least six upper hinge supports evenly distributed along the axial direction of the upper fixing seat. One end of the upper hinge block is hinged on the upper hinge support, and the other end of the upper hinge block is hinged to one end of the push-pull frame.

4. The pouring formwork according to claim 3, characterized in that: The lower fixing member includes a lower fixing seat and at least six lower hinge supports evenly distributed along the axial direction of the lower fixing seat. One end of the lower hinge block is hinged under the lower hinge support, and the other end of the lower hinge block is hinged to the other end of the push-pull frame.

5. The pouring formwork according to claim 4, characterized in that: The push-pull mechanism also includes an inclined slide, which is fixed on the push-pull frame. The inclined side of the inclined slide faces the main cylinder, and the non-inclined side of the inclined slide is connected to the non-casting surface of the sub-template a through a push-pull rod.

6. The pouring formwork according to claim 5, characterized in that: The driving mechanism a includes a driving motor a, which is arranged on a lower fixed seat, and its output shaft is connected to a screw rod a arranged inside the main cylinder. A connecting limit plate that can move inside the main cylinder is provided inside the main cylinder. The connecting limit plate passes through the guide groove and is connected to the non-inclined side of the inclined slider arranged in the slide groove. The screw rod a passes through the connecting limit plate and is threadedly connected to it.

7. The pouring formwork according to claim 6, characterized in that: A limit plate is also fixedly provided inside the main cylinder. The limit plate has a hole for the screw rod a to pass through. A bearing is provided inside the limit plate, and the screw rod a passes through the bearing and is connected to the limit plate.

8. The pouring formwork according to claim 5, characterized in that: The driving mechanism b includes a threaded sleeve, wherein the threaded sleeve is fixedly arranged on the non-casting surface side of the sub-template b, and its internal thread is connected to one end of the screw rod b, and the other end of the screw rod b extends through the through hole to the interior and is connected to the output shaft of the driving motor b fixed on the inner wall of the main cylinder.

9. The pouring formwork according to any one of claims 1 to 9, characterized in that: The sub-template a includes an arc-shaped plate a with an inner concave portion a on its surface. The sub-template b includes an arc-shaped plate b with an inner concave portion b on its surface. The annular groove is formed by splicing the inner concave portion a and the inner concave portion b.

10. A high-strength tunnel ventilation shaft construction method, characterized by: The following steps are involved: S1, remove the surface soil or loose rock layer and excavate the wellhead section from the ground downwards; S2, a locking ring is installed circumferentially on the inner wall of the wellhead section, and a molded reinforced concrete structure is used to form a single-layer support for the wellhead section; S3, along the longitudinal direction of the ventilation shaft from the wellhead to the well bottom, the construction is carried out in sections. After the excavation of a section is completed, a steel structure is set on the well wall. At the same time, the casting template with the annular convex reinforcement forming structure is hoisted into the well using hoisting equipment; S4, after the casting formwork is completed in the ventilation shaft, concrete is poured into the formwork; S5, after the concrete structure strength reaches the required level, the casting formwork is separated from the concrete structure and lifted out of the ventilation shaft; S6, repeat the above steps S3 to S5 until the ventilation shaft construction is completed.

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