An assembled open-cut tunnel joint and a construction method thereof

Abstract

The present application relates to the field of tunnel construction, particularly relates to a kind of assembly type open cut tunnel joint, including at least two spliced tunnel segment, the tunnel segment includes prefabricated pipe body, the bottom of prefabricated pipe body extends out protruding inverted T section towards side surface, the height of inverted T section is lower than the height of prefabricated pipe body, middle part of inverted T section is fixed with L section, and further include several U type stress reinforcement;Further relates to a kind of construction method of assembly type open cut tunnel joint, characterized in that: including the following steps: S1: prefabricated tunnel segment, U type stress reinforcement is embedded in tunnel segment, and the joint of tunnel segment is prefabricated into inverted T section;One end of U type stress reinforcement is poured in prefabricated pipe body, and the other end is poured in inverted T section.S2: bolt hole is set in the bottom of inverted T section, two blocks of tunnel segment are spliced, after splicing is completed, bolt hole is used for bolt fixing;It reduces the difficulty of tunnel segment assembly.

Description

Technical Field

[0001] This invention relates to the field of tunnel construction, and in particular to a prefabricated open-cut tunnel joint and its construction method. Background Technology

[0002] Currently, prefabricated tunnels are mainly used in prefabricated subway stations and utility tunnels in China. Several issues must be addressed for widespread application, including: the load-bearing capacity of the joints, the difficulty of joint assembly, the waterproofing performance of the joints, the overall structural performance, and construction costs. The design and construction assembly of the segment joints are paramount in prefabricated tunnels. Currently, prefabricated joints are mainly divided into dry joints and wet joints. Subway stations primarily use dry joints, but these have drawbacks such as high assembly precision, a large workload on-site, and poor waterproofing. Wet joints have high requirements for the construction environment, require a large amount of formwork and trolley support devices, and are costly. This invention combines the advantages and disadvantages of both methods to propose a prefabricated open-cut tunnel joint and details its construction method, improving construction speed and saving significant costs.

[0003] Utility model patent application CN218493602U designs a simple self-locking device for prefabricated structural joints, including a socket pin, a receiving cone, and anchor bars. One end of the socket pin is a core rod, and the other end is a splitting rod. The core rod is pre-embedded in the precast reinforced concrete structure of block A, with its exposed portion passing through the structural joint. The receiving cone has an inner cone in the middle and a groove on its inner wall. This type of joint ensures the connectivity and integrity of adjacent components to a certain extent, but it requires too high precision, making it unsuitable for on-site construction, severely impacting construction speed and causing significant losses.

[0004] The invention patent application CN115075848A relates to a quick-connect structure for prefabricated corrugated steel plates. This structure includes a circumferential connector on the circumferential end face of the corrugated steel plate and a longitudinal connector on the longitudinal end face. The circumferential connector is a sliding pin type, and the longitudinal connector is an insert type. This structure places excessively high demands on the precision of the formwork fabrication and assembly during construction. If there are significant errors during the assembly of the insert type connector, the assembly cannot be completed, rendering the connector unusable, increasing construction costs, and affecting the construction schedule.

[0005] Existing prefabricated tunnel joints are difficult to assemble, requiring auxiliary support trolleys during assembly. This results in poor overall integrity, weak connections between adjacent tunnel segments, poor waterproofing, reduced stiffness, and decreased load-bearing capacity. Significant deviations in prefabricated dimensions during assembly can lead to loose connections, structural instability, or even complete assembly failure, increasing on-site workload, construction complexity, and costs. A technology is needed to reduce assembly difficulty and save on formwork usage. Summary of the Invention

[0006] This invention provides a prefabricated open-cut tunnel joint and its construction method, which can reduce the difficulty of assembling tunnel segments.

[0007] To address the aforementioned issues, this solution provides the following technical approach: a prefabricated open-cut tunnel joint comprising at least two spliced ​​tunnel segments. Each tunnel segment includes a precast tube body with a protruding inverted T-shaped cross-section extending laterally from the bottom of the precast tube body. The height of the inverted T-shaped cross-section is lower than the height of the precast tube body. An L-shaped cross-section is fixed in the middle of the inverted T-shaped cross-section. The joint also includes several U-shaped reinforcing bars, one end of which is cast into the precast tube body, and the other end is cast into the inverted T-shaped cross-section. The middle portion of the U-shaped reinforcing bars is exposed above the inverted U-shaped cross-section. The U-shaped reinforcing bars are evenly distributed on both sides of the L-shaped cross-section. When the two tunnel segments are joined, their respective inverted T-shaped cross-sections are fixedly connected, and their L-shaped cross-sections are aligned. The area above the inverted T-shaped cross-section is a cast-in-place area. After the two tunnel segments are fixed, concrete is poured into the cast-in-place area.

[0008] The basic principles and beneficial effects of this scheme are as follows: Pre-fabricating the joints of precast tunnel segments into inverted T-shaped sections facilitates alignment during installation, reduces installation intensity, and enhances the overall structural integrity. The L-shaped section, with its upper layer of cast-in-place concrete, improves the waterproofing performance of the circumferential and longitudinal connections of the joints and strengthens the overall structural integrity, achieving an effect equivalent to cast-in-place construction. U-shaped reinforcing bars inserted below the components improve the connection performance between the upper and lower concrete layers, significantly enhancing structural integrity and increasing the height of the tension zone, thereby increasing the structure's load-bearing capacity. The purpose of pouring concrete in the cast-in-place areas is to strengthen the connection between longitudinal and transverse segments, improve integrity and waterproofing performance, achieving an effect equivalent to cast-in-place construction.

[0009] This solution improves the connection performance between tunnel segments, ensures structural integrity, increases load-bearing capacity under structural stress, and thus enhances the stiffness and mechanical properties of the joints.

[0010] It significantly reduces the precision required for assembly, saves templates, reduces the workload of on-site personnel, increases assembly speed, and saves a lot of costs.

[0011] The combination of precast and cast-in-place concrete takes into account both the quality of the segments and the ease of construction, greatly saves on formwork, is environmentally friendly, reduces construction difficulty, and improves the load-bearing capacity of the structure.

[0012] Because the top of the joint is made of cast-in-place concrete and is cast as a single piece, the waterproof performance of the joint is greatly improved, increasing the durability, integrity, and safety of the structure.

[0013] Furthermore, it also includes an additional elongated ring, which is fixedly connected to the U-shaped reinforcing bars of the two spliced ​​tunnel segments.

[0014] Beneficial effects: Function: Connects the reinforcing bars of adjacent pipe segments together, improving the overall integrity of adjacent pipe segments. At the same time, the addition of the long circular ring is equivalent to increasing the reinforcement of the reinforcing bars at the joint, effectively increasing the load-bearing capacity and stiffness of the joint.

[0015] Furthermore, several aggregate particles are fixed on the inverted T-shaped cross-section.

[0016] Beneficial effects: Applying a retarder to the joint contact side mold, and rinsing the precast components with a high-pressure water gun after demolding until the coarse aggregate is exposed. Function: Increases the roughness of the new and old concrete, improving the bond performance between them.

[0017] Furthermore, bolt holes are provided at the bottom of the inverted T-shaped section, and the bolt holes of the two tunnel segments that are spliced ​​together are matched, and the two tunnel segments are fixed by bolts through the bolt holes.

[0018] Beneficial effects: After the components are assembled, the shear resistance of the structure during the assembly stage is improved, the connection performance of the circumferential segments is enhanced, the crack resistance at the joints is increased, it serves as a temporary fastener, and increases construction safety.

[0019] Furthermore, each tunnel segment has 6-8 reinforcing steel bars.

[0020] Furthermore, it also includes longitudinal short bars, which are fixedly connected to two adjacent U-shaped reinforcing bars.

[0021] Beneficial effects: Strengthens the connection of U-shaped steel bars between adjacent pipe segments and improves the load-bearing capacity of the joint.

[0022] A construction method for a prefabricated open-cut tunnel joint includes the following steps:

[0023] S1: Precast tunnel segments, with U-shaped reinforcing bars pre-embedded in the tunnel segments, and the joints of the tunnel segments precast into inverted T-shaped sections; one end of the U-shaped reinforcing bars is cast in the precast tube body, and the other end is cast in the inverted T-shaped section.

[0024] S2: Bolt holes are opened at the bottom of the inverted T-shaped section to splice the two matching tunnel segments. After splicing, bolts are used to fix them through the bolt holes.

[0025] S3: The U-shaped reinforcing bars of the two tunnel segments that cooperate with each other are fixed by an additional long circular ring;

[0026] S4: Adjacent U-shaped reinforcing bars are fixed by longitudinal break bars;

[0027] S5: Pour concrete into the cast-in-place area above the inverted T-shaped section.

[0028] The tunnel segment joints in this design utilize inverted T-shaped prefabrication, significantly reducing assembly difficulty and saving considerable formwork. U-shaped reinforcing bars are used, embedded in the base slab. After the concrete is poured in place, this strengthens the bond between the base slab and the cast-in-place concrete. Bolt holes are pre-drilled at the bottom for bolt connection after assembly, improving structural integrity and increasing crack resistance at the joints. The reinforcing bars of the left and right prefabricated blocks are connected with additional long circular rings and reinforced with longitudinal short bars. Finally, the concrete is poured in place, improving the overall structural performance and achieving an effect equivalent to cast-in-place construction. The waterproofing performance of the structure is also greatly enhanced. Attached Figure Description

[0029] Figure 1 A three-dimensional schematic diagram of the assembled prefabricated open-cut tunnel joint;

[0030] Figure 2 This is a front view of a prefabricated open-cut tunnel joint;

[0031] Figure 3 This is a top view of a prefabricated open-cut tunnel joint;

[0032] Figure 4 A bottom view of a prefabricated open-cut tunnel joint;

[0033] Figure 5 This is a three-dimensional schematic diagram of the precast tunnel segment on the left.

[0034] Figure 6 A schematic diagram of the U-shaped reinforcing steel bars and the additional long circular ring;

[0035] Figure 7 A schematic diagram showing the completion of the cast-in-place area;

[0036] Figure 8 This is a schematic diagram of a second embodiment of a prefabricated open-cut tunnel joint assembly.

[0037] Figure 9 for Figure 8 Enlarged diagram of point A in the middle. Detailed Implementation

[0038] The following detailed description illustrates the specific implementation method:

[0039] The markings in the attached drawings of the instruction manual include: 1. Precast pipe body; 2. U-shaped reinforcing bar; 3. Bolt hole; 4. Inverted T-shaped section; 5. L-shaped section; 6. Aggregate particles; 7. Longitudinal short bar; 8. Additional long ring; 9. Cast-in-place area; 10. First channel; 11. Second channel; 13. Locking bolt; 12. Detection ball; 131. Contact table; 132. Puncture needle.

[0040] Example 1 is attached. Figure 5 As shown,

[0041] A prefabricated open-cut tunnel joint is installed on one side of a tunnel segment. The tunnel segment includes a precast tube body 1. The bottom of the precast tube body 1 extends to the side to form a protruding inverted T-shaped section 4. The top surface of the inverted T-shaped section 4 is flush with the bottom surface of the precast tube body 1. The bottom surface of the inverted T-shaped section 4 extends downward. In this design, the extension length is half the height of the precast tube body 1. The left side of the inverted T-shaped section 4 extends to the bottom of the precast tube body 1. The connection is chamfered. The inverted T-shaped section 4 and the precast tube body 1 are fixed together by pouring concrete. An L-shaped section 5 is fixed in the middle of the inverted T-shaped section 4. The L-shaped section 5 is located in the middle position of the inverted T-shaped section 4.

[0042] It also includes eight U-shaped reinforcing bars 2, one end of which is cast into the precast pipe body 1, and the other end is cast into the inverted T-shaped section 4. The middle part of the U-shaped reinforcing bars 2 is exposed above the inverted T-shaped section 4; the U-shaped reinforcing bars 2 are as shown in the attached figure. Figure 6 As shown. The U-shaped steel bars are evenly distributed on both sides of the L-shaped section 5, and four U-shaped reinforcing steel bars 2 are respectively set on both sides of the L-shaped section 5.

[0043] As attached Figure 1 and attached Figure 6 As shown, it also includes additional long rings 8, which are fixedly connected to the U-shaped reinforcing bars 2 of the two spliced ​​tunnel segments. It also includes longitudinal short bars 7, which are fixedly connected to two adjacent U-shaped reinforcing bars 2. The function of the longitudinal short bars 7 is to strengthen the connection of the U-shaped reinforcing bars of adjacent segments and improve the load-bearing capacity of the joint. The function of the additional long rings 8 is to connect the reinforcing bars of adjacent segments together, improving the overall integrity of the adjacent segments. Simultaneously, the addition of the additional long rings 8 is equivalent to increasing the reinforcement of the reinforcing bars at the joint, effectively increasing the load-bearing capacity and stiffness of the joint. The anchorage length of the additional long rings 8 and the short bars is sufficient at L / 3 of the overlapping area; that is, short bars should be used for reinforcement at L / 3 on both sides of the additional long rings 8.

[0044] As attached Figure 1 As shown, the two precast tunnel segments are symmetrically arranged. Figure 5 The image shows the precast tunnel segment on the left. When the two tunnel segments are assembled, their inverted T-shaped sections 4 are fixedly connected, and their L-shaped sections 5 are aligned. Above the inverted T-shaped sections 4 is the cast-in-place area 9. After the two tunnel segments are fixed, as shown in the attached diagram... Figure 7 As shown, concrete is poured for the cast-in-place area 9.

[0045] Several aggregate particles 6 (not shown in the figure) are fixed on the inverted T-shaped section 4, specifically covering the outer surface of the inverted T-shaped section 4. During construction, a retarder is applied to the joint contact side mold. After the precast component is demolded, it is washed with a high-pressure water gun until the coarse aggregate is exposed. Function: To increase the roughness of the new and old concrete and improve the bonding performance between them.

[0046] The bottom of the inverted T-shaped section 4 has bolt holes 3. The bolt holes 3 of the two interlocking tunnel segments mate, and the two tunnel segments are fixed together by bolts through the bolt holes 3. The construction method for the aforementioned joint is also described, including the following steps:

[0047] S1: Precast tunnel segments, with U-shaped reinforcing bars pre-embedded in the tunnel segments, and the joints of the tunnel segments precast into inverted T-shaped sections; one end of the U-shaped reinforcing bars is cast in the precast tube body, and the other end is cast in the inverted T-shaped section.

[0048] S2: Bolt holes are opened at the bottom of the inverted T-shaped section to splice the two matching tunnel segments. After splicing, bolts are used to fix them through the bolt holes.

[0049] S3: The U-shaped reinforcing bars of the two tunnel segments that cooperate with each other are fixed by an additional long circular ring;

[0050] S4: Adjacent U-shaped reinforcing bars are fixed by longitudinal break bars;

[0051] S5: Pour concrete into the cast-in-place area above the inverted T-shaped section.

[0052] Example 2

[0053] The difference between Example 2 and Example 1 is that the two precast segments assembled are as shown in the attached figure. Figure 8 As shown, the precast segment on the left has a first channel 10 diagonally opened towards the lower right. The first channel 10 extends into the precast segment on the right. The first channel 10 is connected to the bottom of the bolt hole 3 (in this scheme, the bottom of the bolt hole 3 refers to the place where the tail of the bolt contacts when the locking bolt 13 is installed). The tail of the first channel 10 is narrowed. It also includes a second channel 11. The second channel 11 is inclined. The upper end of the second channel 11 is connected to the bottom end of the first channel 10, and the other end is opened at the bottom of the precast segment on the right. The two parts of the second channel 11 on the left and right precast segments cooperate with each other and are connected.

[0054] The contact point between the end of the first channel 10 and the upper end of the second channel 11 is the minimum diameter of the two channels. After installation, the detection ball 12 is inserted through the opening at the upper end of the first channel 10. The detection ball 12 is made of rubber, and the material of the detection ball 12 can be selected by those skilled in the art according to actual operation, ensuring that the detection ball can be pierced by the locking bolt 13. The inside of the detection ball 12 is filled with liquid pigment. The diameter of the detection ball 12 is larger than the minimum diameter of the first channel 10 and smaller than the maximum diameter of the first channel 10, so that it is just stuck at the connection position between the first channel 10 and the bolt hole 3.

[0055] After aligning the left and right precast segments, the locking bolts 13 are screwed into the bolt holes 3 on the left precast segment and into the bolt holes 3 on the right precast segment, thus locking the two precast segments. The locking bolts 13 are as shown in the attached figure. Figure 9 As shown, a contact platform 131 is provided at the tail end. The projection of the contact platform 131 is an inverted trapezoid. The lower bottom surface of the contact platform 131 is fixed to the tail end of the locking bolt 13. A puncture needle 132 is fixed around the side of the contact platform 131. The length of the puncture needle does not exceed the upper bottom surface of the contact platform 131. A filter screen is fixed at the bottom of the second channel 11. The filter holes of the filter screen are smaller than 1 / 3 and larger than 1 / 4 of the bottom diameter of the second channel. This is used to prevent the broken detection ball 12 from falling out of the second channel. At the same time, the broken detection ball 12 can be pulled out from the filter holes. That is, the punctured detection ball 12 is deformed by pulling and then pulled out from the filter holes.

[0056] In actual installation, the left precast segment is first fixed, then the right precast segment is moved closer to it and the two segments are joined together. Air is blown into the first channel 10, and the gas exits from the outlet of the second pipe 11, blowing out impurities from both channels. A detection ball 12 is then placed in the first channel 10 and slides along the first channel 10 to the bottom of the bolt hand hole 4. The locking bolt 13 is then screwed in. The installer can determine whether the locking bolt 13 is properly tightened by the tactile change when it contacts the detection ball 12. Alternatively, a person skilled in the art can install a corresponding sensor on the contact platform 131 to detect whether the bolt is tightened to the contact position by the pressure change on the contact platform 131. After tightening to the contact position, tighten the locking bolt 13 to the end position, with a tightening angle of 360°-720°, i.e., one to two turns. As the locking bolt 13 is pushed forward, the contact platform 131 squeezes and deforms the detection ball 12. Then, the puncture needle 132 contacts the detection ball 12. As the locking bolt 13 rotates, the detection ball 12 will be punctured at multiple points. There are 4 puncture needles 132 to ensure that the internal pigment can flow out. After observing the pigment flowing out, it is determined that the left and right precast blocks are aligned and the pouring work can begin. At this time, it can be disassembled and adjusted, and air can be blown into the channel again to blow away the impurities. The detection ball 12 is put back in and the above operation is repeated until the requirements are met.

[0057] After the left and right precast segments are aligned, the locking bolt 13 is screwed into the bolt hole 3 on the left precast segment and into the bolt hole 3 on the right precast segment, locking the two precast segments. The tail of the locking bolt 13 is pointed. When it contacts the detection ball 12 and the locking bolt 13 is continuously rotated, it will puncture the detection ball 12, and the pigment inside will flow out along the second channel 11. Construction workers can judge whether the two precast segments are aligned by observing whether pigment flows out of the second channel 11. At the same time, the detection ball 12 also serves as a prompt, limiting the screwing state of the locking bolt 13 to avoid under-screwing or over-screwing. During pouring, the concrete is poured layer by layer from bottom to top. When pouring the concrete into the opening above the first channel 10, the concrete enters from the opening of the first channel 10, flows through the first channel 10, and flows out from the second channel 11. Workers can judge whether the two precast segments have shifted before pouring during the assembly process by observing whether concrete flows out of the second channel 11. The installation status of the two precast tunnel segments was monitored by detecting both the detection ball 12 and whether concrete flowed out, preventing displacement and potential safety hazards. The concrete within the two channels allows for the re-pouring of both channels, preventing voids and ensuring structural stability. Furthermore, since the bottom of bolt hole 3 is connected to the first channel 10, as concrete flows down into the first channel 10, it can also enter bolt hole 3 from the bottom, filling the gap between bolt hole 3 and locking bolt 13, further reducing the possibility of loosening of the two precast tunnel segments during later use. Additionally, when concrete flows into the second channel 11, a portion of it is blocked by the punctured detection ball 12, preventing direct overflow and waste.

[0058] The above are merely embodiments of the present invention. The invention is not limited to the fields covered by these embodiments. Commonly known structures and characteristics in the solutions are not described in detail here. Those skilled in the art are aware of all common technical knowledge in the field prior to the application date or priority date, are able to access all existing technologies in that field, and have the ability to apply conventional experimental methods prior to that date. Those skilled in the art can, based on the guidance provided in this application, improve and implement this solution in combination with their own capabilities. Some typical known structures or methods should not be obstacles for those skilled in the art to implement this application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present invention. These should also be considered within the scope of protection of the present invention, and will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application shall be determined by the content of its claims.

Claims

1. A prefabricated open-cut tunnel joint, comprising at least two spliced ​​tunnel segments, characterized in that, The tunnel segment includes a precast tube body with a protruding inverted T-shaped cross-section extending laterally from the bottom. The height of the inverted T-shaped cross-section is lower than the height of the precast tube body. An L-shaped cross-section is fixed in the middle of the inverted T-shaped cross-section. It also includes several U-shaped reinforcing bars, one end of which is cast into the precast tube body, and the other end is cast into the inverted T-shaped cross-section. The middle of the U-shaped reinforcing bars is exposed above the inverted T-shaped cross-section. The U-shaped reinforcing bars are evenly distributed on both sides of the L-shaped cross-section. When two tunnel segments are assembled, the inverted T-shaped cross-sections of the two tunnel segments are fixedly connected, and the L-shaped cross-sections are aligned. The area above the inverted T-shaped cross-section is a cast-in-place area. After the two tunnel segments are fixed, concrete is poured into the cast-in-place area. A first channel is obliquely opened on the left precast tube segment, facing downward to the right, and the first channel extends into the right side. In the precast tunnel segment, bolt holes are opened at the bottom of the inverted T-shaped section. The bolt holes of two tunnel segments that are spliced ​​together are matched, and the two tunnel segments are fixed by bolts through the bolt holes. The bottom of the first channel and the bolt holes are connected. The tail of the first channel is set with a narrowing. It also includes a second channel, which is inclined. The upper end of the second channel is connected to the bottom end of the first channel, and the other end is opened at the bottom of the right precast tunnel segment. A detection ball is inserted through the opening at the upper end of the first channel. The detection ball is made of rubber and filled with liquid pigment. A locking bolt is provided with a contact platform at the tail. The projection of the contact platform is an inverted trapezoid. The lower bottom surface of the contact platform is fixed to the tail of the locking bolt. A puncture needle is fixed around the side of the contact platform. The length of the puncture needle does not exceed the upper bottom surface of the contact platform. A filter screen is fixed at the bottom of the second channel.

2. The prefabricated open-cut tunnel joint according to claim 1, characterized in that: It also includes an additional elongated ring, which is fixedly connected to the U-shaped reinforcing bars of the two spliced ​​tunnel segments.

3. A prefabricated open-cut tunnel joint according to claim 1, characterized in that: Several aggregate particles are fixed on the inverted T-shaped cross-section.

4. A prefabricated open-cut tunnel joint according to claim 1, characterized in that: Each tunnel segment has 6-8 reinforcing steel bars.

5. A prefabricated open-cut tunnel joint according to claim 1, characterized in that: It also includes longitudinal short bars, which are fixedly connected to two adjacent U-shaped reinforcing bars.

6. A construction method applicable to the prefabricated open-cut tunnel joint according to any one of claims 1-5, characterized in that: Includes the following steps: S1: Precast tunnel segments, with U-shaped reinforcing bars pre-embedded in the tunnel segments, and the joints of the tunnel segments precast into inverted T-shaped sections; one end of the U-shaped reinforcing bars is cast in the precast tube body, and the other end is cast in the inverted T-shaped section; S2: Bolt holes are opened at the bottom of the inverted T-shaped section to splice the two matching tunnel segments. After splicing, bolts are used to fix them through the bolt holes. S3: The U-shaped reinforcing bars of the two tunnel segments that cooperate with each other are fixed by an additional long circular ring; S4: Adjacent U-shaped reinforcing bars are fixed by longitudinal break bars; S5: Pour concrete into the cast-in-place area above the inverted T-shaped section.

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