Tunnel inverted arch construction method and device

Abstract

The application discloses a tunnel inverted arch construction method and device, and relates to the technical field of tunnel construction. The method adopts multi-point inverted arch precast block synchronous installation in a tunnel construction section. When a jump space area is generated, the jump pouring formwork and the access trestle are hoisted as a whole to the jump space area by a lifting appliance. The side formwork is fitted with the side surface of the installed precast block and is fixed. The ditch formwork is corresponded with the ditch groove of the precast block. Concrete is poured, vibration and maintenance are cooperated, a passing trestle is erected above the jump space area for passing during the period, and the whole is hoisted to the next jump space area after the formwork is removed to repeat the operation. The device comprises the jump pouring formwork, the access trestle and the lifting appliance. The jump pouring formwork is composed of the side formwork and the ditch formwork and is used for forming a pouring cavity in the jump space area. The lifting appliance realizes the integral hoisting of the formwork and the trestle. The application can realize rapid pouring and rapid switching of passing in the jump space area, has high positioning precision, good connection quality, significantly improves the construction efficiency, and reduces material consumption and labor cost.

Description

Technical Field

[0001] This invention relates to the field of tunnel construction technology, and in particular to a method and apparatus for constructing a tunnel invert arch. Background Technology

[0002] As a core component of tunnel lining structure, the invert arch plays a crucial role in transferring superstructure loads, constraining surrounding rock deformation, and preventing foundation heave and uneven settlement. Compared to traditional cast-in-place invert arch construction, the prefabricated block production and on-site assembly installation of invert arches effectively solves the pain points of cast-in-place construction, such as long construction period, large quality fluctuations, and poor on-site working environment, and its application in tunnel engineering is becoming increasingly widespread.

[0003] In actual construction, due to factors such as arch frame installation errors and changes in geological conditions, the precast blocks of the invert arch installed simultaneously at multiple points often cannot form an integer multiple of the standard block spacing, resulting in discontinuous gap areas. These areas cannot be directly installed with precast blocks and require in-situ casting. However, existing methods for casting these gap areas face several technical bottlenecks: Firstly, the casting molds are mostly simple glued plywood templates, requiring on-site measurement of the gap length, segmental assembly, positioning, and disassembly. These templates can only be used once, have a short lifespan, and consume a lot of materials. This not only makes the construction process cumbersome and inefficient, but also makes it difficult to guarantee the positioning accuracy of the templates, easily leading to loose connections between the cast body and the precast blocks in the gap areas, resulting in quality problems such as misalignment and gaps. Secondly, tunnel construction space is limited, and existing molds require individual formwork erection and disassembly. The plywood is difficult to separate from the concrete, and it is not easy to clean the formwork residue from the concrete. A single cycle of casting takes more than 4 hours, and the gap casting operation conflicts with the passage of construction vehicles, affecting the continuity of the work process.

[0004] In the prior art, although there are some devices that combine invert arch trestle bridges with formwork, such as the utility model patent with authorization announcement number CN209277897U, which discloses a trestle bridge for the construction of invert arch formwork in a single-line tunnel, realizing the connection between the trestle bridge and the formwork, this device is mainly designed for cast-in-place invert arch formwork and does not consider the special pouring requirements of the gap area between invert arch precast blocks, and cannot adapt to the precise pouring positioning of the gap area.

[0005] Therefore, in order to address the problems of low efficiency, poor positioning accuracy, conflict between passage and construction, and poor connection quality in the existing technology of skip-casting between precast invert arch blocks, it is of great significance to develop a construction method and device that integrates a skip-casting rapid mold and a passage trestle, which is accurate in positioning, convenient in operation, and can guarantee the casting quality. Summary of the Invention

[0006] The purpose of this invention is to provide a method and apparatus for constructing tunnel inverts in order to solve the above-mentioned problems.

[0007] The present invention achieves the above objectives through the following technical solutions: A method for constructing a tunnel invert arch, characterized in that, when multiple invert arch precast blocks are installed simultaneously at multiple points in the tunnel construction section, and when there is a gap between adjacent points in the construction section that is insufficient to install one invert arch precast block, the following steps are performed: Step 1: Provide invert arch construction equipment, including a jump-cast formwork, a passage trestle, and lifting equipment. The jump-cast formwork includes side formwork and drainage ditch formwork. Step 2: The formwork for the suspended pouring and the access bridge are hoisted to the suspended area using the hoisting equipment. The side formwork is fitted and fixed to the side of the precast inverted arch block. The drainage ditch formwork corresponds to the drainage ditch of the precast inverted arch block. Step 3: Pour concrete into the casting cavity enclosed by the skip casting template, and combine it with vibration and curing to make the casting body reach the design strength; during this period, a passage bridge is built above the skip area for passage in the skip area; Step 4: Remove the formwork for the skip-casting, and use the lifting equipment to transport the formwork and the access trestle to the skip area waiting to be poured. Repeat steps 1 to 4 until the tunnel invert arch construction is completed.

[0008] Additionally, a tunnel invert construction device is provided for the above method, comprising: A skip-casting template, comprising side templates and drainage ditch templates, is used to form a casting cavity in the skip area between the precast blocks of the invert arch; A passageway bridge, used to erect over the completed concrete gap for the passage of construction vehicles and personnel; and The lifting device is detachably connected to the suspended pouring formwork and the passage trestle, and is used to realize the overall lifting and transportation of the suspended pouring formwork and the passage trestle.

[0009] Preferably, the skip-casting template further includes a fixing screw for connecting the side template to the bedrock surface, and a support rod for supporting the ditch template.

[0010] Preferably, the drainage ditch template is U-shaped, and a support rod is installed inside the drainage ditch template. The support rod includes a threaded sleeve and lead screws inserted at both ends of the threaded sleeve. The lead screws are threadedly connected to the threaded sleeve, and the two lead screws have opposite thread directions. The two lead screws are respectively hinged to both sides of the drainage ditch template. The opening size of the drainage ditch template can be adjusted by rotating the threaded sleeve.

[0011] Preferably, it also includes a high-frequency vibrator for eliminating air bubbles during the concrete pouring process.

[0012] Preferably, the frequency of the high-frequency vibrator can be adjusted to 200Hz.

[0013] Preferably, it also includes a curing blanket, which is equipped with an electric heating wire for heating and curing the poured concrete.

[0014] Preferably, the electric heating wire controls the concrete curing temperature at 60±5℃.

[0015] Preferably, the main body of the passageway adopts a steel arch bridge structure, and the surface of the wing plate is provided with anti-slip texture.

[0016] Preferably, the lifting device is a traveling crane mechanism, which can realize the overall movement and hoisting of the skip-cast formwork and the passage trestle in the tunnel.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. By installing precast blocks synchronously at multiple points, there is no need to accurately measure and reserve integer block spacing, avoiding repeated manual adjustments; the formwork and trestle are lifted as a whole by a hoist, enabling rapid assembly and disassembly. According to on-site measurements, the single-cycle pouring time is reduced from the traditional 4 hours to 1.5 hours, and the overall construction speed reaches 16m / day, which is more than 160% faster than the traditional method. 2. High-strength steel molds and screw fine-tuning mechanisms are adopted to control the positioning accuracy within 5mm, ensuring a tight connection between the skip-cast body and the precast invert arch block, effectively avoiding misalignment, gaps and leakage problems, and reducing the leakage rate of the invert arch to below 0.3%; 3. By adopting the strategy of "integrated mold casting - synchronous construction vehicle passage", the trestle can be hoisted into place after the formwork is removed, realizing a quick switch between casting and passage, and solving the problem of conflict between passage and casting in traditional construction. 4. The templates are reusable, reducing material consumption; the manual formwork erection and dismantling processes are reduced, significantly lowering labor costs. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the front view structure of the side formwork of the skip-casting formwork in this invention; Figure 2 This is a top view of the side formwork of the skip-casting formwork in this invention. Figure 3 This is a schematic diagram of the left side formwork of the skip-casting formwork in this invention.

[0020] Figure 4This is a schematic diagram of the main structure of the water ditch template for the skip-casting template in this invention; Figure 5 This is a top view of the water ditch template for the skip-casting template in this invention. Figure 6 This is a schematic diagram of the left-side structure of the passageway bridge in this invention.

[0021] Figure 7 This is a schematic diagram of the overhead walkway structure in this invention, viewed from below.

[0022] The annotations in the attached figures are explained as follows: 1. First plate; 2. First lifting lug; 3. Second plate; 4. Support rod; 5. Second lifting lug; 6. Passage plate; 7. Wing plate; 8. Supporting steel; 9. Third lifting lug. Detailed Implementation

[0023] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. In addition, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation", "connection", and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components. For those skilled in the art, the specific meaning of the above terms in this invention can be understood through the specific circumstances.

[0025] The present invention will be further described below with reference to the accompanying drawings: Example 1

[0026] This embodiment provides a method for constructing a tunnel invert arch, specifically applied in a twin-tube single-track tunnel.

[0027] First, within the tunnel construction section, a multi-point synchronous installation method was adopted to install the prefabricated invert arch blocks from the factory according to the design positions. Due to the installation error of the arch frame and the influence of geological conditions, a gap zone with a width of approximately 0.5m to 1.0m naturally formed between adjacent installation points, and the prefabricated blocks could not be directly installed in this area.

[0028] Subsequently, the invert arch construction device of the present invention is provided. This device includes a skip-casting formwork, a passageway, and lifting equipment. The skip-casting formwork consists of side formwork and drainage ditch formwork. For example... Figures 1-3 As shown, the side formwork includes a first plate 1, which is a flat plate with reinforcing ribs on the side away from the pouring area. Two first lifting lugs 2 are installed on the first plate 1. A fixing screw (not shown in the figure) is hinged to the side of the first plate 1 away from the pouring area for fixing the side formwork to the bedrock surface. The posture of the first plate 1 can be adjusted by extending and retracting the fixing screw, so that it fits against the sides of the precast arch blocks on both sides of the gap area. The first plate 1 is made of 3mm thick steel plate, and the reinforcing ribs are reinforced with 5mm steel plates. A release agent is applied to the side of the first plate 1 closest to the pouring area. Figures 4-5 As shown, the drainage ditch template includes a second plate 3 with a U-shaped end face. The outer surface of the second plate 3 is coated with a release agent. Inside the drainage ditch template, a support rod 4 is installed at the top for adjusting the opening and closing of the side plates. The support rod 4 includes a threaded sleeve and threaded rods inserted at both ends of the threaded sleeve. The threaded rods are threadedly connected to the threaded sleeve, with opposite thread directions. The two threaded rods are hinged to both sides of the drainage ditch template. The opening size of the drainage ditch template is adjusted by rotating the threaded sleeve. When installing the drainage ditch template, the opening is reduced to facilitate alignment of both ends with the drainage ditch position on the precast arch block. Then, the support rod 4 is adjusted to open the drainage ditch template to fit against the side of the drainage ditch on the precast arch block. Two second lifting lugs 5 are fixedly installed on the bottom surface inside the second plate 3. Figures 6-7 As shown, the passageway includes two supporting steel sections 8 placed on the precast invert blocks on both sides of the gap area. A passageway plate 6 is welded between the supporting steel sections 8. A wing plate 7 is installed on the side of the supporting steel section 8 away from the passageway steel section. The wing plate 7 is an inclined surface connecting the top surface of the supporting steel section 8 and the upper surface of the precast invert block. Anti-slip textures are provided on the wing plate 7. A sunken third lifting lug 9 is set in the middle of the supporting steel section 8. The passageway plate 6, wing plate 7, and supporting steel section 8 are all made of Q420 high-strength steel. The lifting equipment adopts a traveling crane mechanism, which can move longitudinally along the tunnel. By hooking the first lifting lug 2, second lifting lug 5, and third lifting lug 9 on the traveling crane mechanism, the entire gap-cast formwork can be lifted to the gap area position and slowly lowered.

[0029] Then, the operators install fixing screws between the side template and the bedrock surface. The fixing screws have the same structure as support rod 4. By fine-tuning the fixing screws, the side template is made to fit tightly with the sides of the precast invert blocks that have been installed on both sides of the ditch. The ditch template is then placed corresponding to the ditch position of the precast invert blocks, and is installed and tightened by adjusting the extension and retraction of support rod 4.

[0030] After the formwork for the suspended pouring is installed, concrete is poured into the pouring cavity enclosed by the formwork. During the pouring process, a high-frequency vibrator is activated to eliminate air bubbles, and curing is carried out using a curing blanket equipped with electric heating wires. During curing, the concrete temperature is controlled between 25℃ and 35℃, the humidity is controlled above 90%, and the temperature difference between the curing water and the surface is no more than 15℃. On-site measurements show that the concrete reaches its usable strength within 6 hours. During the curing process, a passageway is erected above the suspended area to create a roadway for concrete transport trucks and other construction vehicles.

[0031] After the pouring and curing are completed, the fixing screws and support rods 4 are adjusted to demold the side formwork and the water ditch formwork. The formwork and the passage trestle are then hoisted to the next gap area to be poured by the hooks of the traveling crane mechanism, forming a passage for construction vehicles such as concrete transport trucks.

[0032] The foregoing has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are only illustrative of the principles of the present invention. Various changes and modifications can be made to the present invention without departing from the spirit and scope of the present invention, and all such changes and modifications fall within the scope of the present invention as claimed.

Claims

1. A method for constructing a tunnel invert arch, characterized in that, When multiple precast invert blocks are installed simultaneously at multiple points in a tunnel construction section, and there is a gap between adjacent points in the construction section that is insufficient to install one precast invert block, the following steps shall be performed: Step 1: Provide invert arch construction equipment, including a jump-cast formwork, a passage trestle, and lifting equipment. The jump-cast formwork includes side formwork and drainage ditch formwork. Step 2: The formwork for the suspended pouring and the access bridge are hoisted to the suspended area using the hoisting equipment. The side formwork is fitted and fixed to the side of the precast inverted arch block. The drainage ditch formwork corresponds to the drainage ditch of the precast inverted arch block. Step 3: Pour concrete into the pouring cavity formed by the skip-pouring template, and combine it with vibration and curing to make the poured body reach the design strength; During this period, a passage bridge will be built above the jump area for passage through the jump area; Step 4: Remove the formwork for the skip-casting, and use the lifting equipment to transport the formwork and the access trestle to the skip area waiting to be poured. Repeat steps 1 to 4 until the tunnel invert arch construction is completed.

2. A tunnel invert arch construction device, characterized in that, For implementing the method of claim 1, comprising: A skip-casting template, comprising side templates and drainage ditch templates, is used to form a casting cavity in the skip area between the precast blocks of the invert arch; A passageway bridge, used to erect over the completed concrete gap for the passage of construction vehicles and personnel; and The lifting device is detachably connected to the suspended pouring formwork and the passage trestle, and is used to realize the overall lifting and transportation of the suspended pouring formwork and the passage trestle.

3. The tunnel invert construction device according to claim 2, characterized in that, The skip-casting template also includes a fixing screw for connecting the side template to the bedrock surface, and a support rod (4) for supporting the ditch template.

4. The tunnel invert construction device according to claim 3, characterized in that, The shape of the ditch template is U-shaped. A support rod (4) is installed inside the ditch template. The support rod (4) includes a threaded sleeve and screws inserted at both ends of the threaded sleeve. The screws are threaded to the threaded sleeve. The two screws have opposite thread directions and are respectively hinged to both sides of the ditch template. The size of the opening of the ditch template can be adjusted by rotating the threaded sleeve.

5. The tunnel invert construction device according to claim 2, characterized in that, It also includes a high-frequency vibrator, used to eliminate air bubbles during the concrete pouring process.

6. The tunnel invert construction device according to claim 5, characterized in that, The frequency of the high-frequency vibrator can be adjusted to 200Hz.

7. The tunnel invert construction device according to claim 2, characterized in that, It also includes a curing blanket, which is equipped with electric heating wires for heating and curing the poured concrete.

8. The tunnel invert construction device according to claim 7, characterized in that, The electric heating wire controls the concrete curing temperature at 60±5℃.

9. The tunnel invert construction device according to claim 2, characterized in that, The main body of the passage bridge adopts a steel arch bridge structure, and the surface of the wing plate (7) is provided with anti-slip texture.

10. The tunnel invert construction device according to claim 2, characterized in that, The lifting device is a traveling crane mechanism, which can realize the overall movement and hoisting of the suspended pouring formwork and the passage trestle in the tunnel.

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