Tunnel segment mold, segment, preparation method and construction method

Abstract

The invention discloses a tunnel duct piece mold, a duct piece, a preparation method and a construction method, and the tunnel duct piece mold comprises a duct piece pouring cavity used for pouring a duct piece main body; the core rod is sleeved with an embedded sleeve and used for forming a bolt penetrating hole in the duct piece main body; the hand hole die comprises a fixed part and a detachable part and is used for forming a bolt hand hole communicating with the bolt penetrating hole in the duct piece body, the fixed part is arranged on the surface of the bottom of the duct piece pouring cavity, the detachable part is detachably connected with the fixed part, a protruding part is formed on the surface of the detachable part, and the protruding part is detachably connected with the fixed part. A groove is formed in the inner surface of the bolt hand hole. The possibility that the bolt hand hole plugging block falls off can be reduced, so that the reliability of a tunnel structure is improved, and the overhaul work requirement in the operation period is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field related to tunnel segments. More specifically, the present invention relates to a tunnel segment mold, a segment, a preparation method, and a construction method. Background Art

[0002] Shield tunnels are widely used in urban subways, water conveyance tunnels and other fields. In shield tunnel construction, the bolt handholes inside the segments are usually backfilled with concrete (forming a plug). In the prior art, this backfilling method mainly relies on the bonding force between the old and new concrete interfaces to fix the plug. However, this bonding force has many limitations. On the one hand, during the concrete construction process, factors such as the cleanliness, humidity of the handhole wall, and the difference in the characteristics of the old and new concrete materials will affect the magnitude of the bonding force, resulting in a small and unstable bonding force. On the other hand, during the tunnel operation period, affected by complex factors such as formation deformation, vibration, and temperature change, the concrete will undergo deformations such as shrinkage and creep, further weakening the bonding force between the old and new concrete. Once the bonding force decreases and the plug of the bolt handhole falls off, it may bring greater risks to the tunnel operation. For water conveyance tunnels lacking maintenance conditions, the above problems are more critical. The fallen concrete plug may block the grid holes in the tunnel, affect the water flow through, reduce the water conveyance efficiency, and at the same time expose the connecting bolts directly to the environment, making them prone to corrosion, reducing the reliability of the segment connection, and threatening the tunnel structure safety; in addition, after the plug falls off, the roughness of the tunnel inner wall increases, which not only increases the water flow resistance, but also may lead to intensified local scouring and shorten the service life of the tunnel.

[0003] Therefore, it is necessary to design a technical solution that can overcome the above defects to a certain extent. Summary of the Invention

[0004] An object of the present invention is to provide a tunnel segment mold, a segment, a preparation method, and a construction method, which can reduce the possibility of the plug of the bolt handhole falling off.

[0005] To achieve the above object and other advantages of the present invention, according to one aspect of the present invention, there is provided a tunnel segment mold for preparing a segment with a bolt handhole, including: a segment casting cavity for casting a segment body; a core rod, an embedded sleeve is sleeved outside the core rod, for forming a bolt through-hole in the segment body; a handhole mold, which includes a fixed part and a detachable part, for forming a bolt handhole communicating with the bolt through-hole in the segment body, the fixed part is arranged on the bottom surface of the segment casting cavity, the detachable part is detachably connected to the fixed part, and a protruding part is formed on the surface of the detachable part, for forming a groove on the inner surface of the bolt handhole.

[0006] Furthermore, a slot is provided on the side of the fixing part, and the extending direction of the slot is along the direction in which the segment body is taken out from the segment casting cavity. The detachable part is matched with the shape of the slot. A magnet is provided on one surface of the slot, and the detachable part is made of a ferromagnetic material.

[0007] Furthermore, the slot includes a bottom surface and at least two side surfaces. At least two of the side surfaces clamp the detachable part, and the magnet is provided on the bottom surface.

[0008] Furthermore, the protruding part gradually decreases in size from near the detachable part to far away from the detachable part.

[0009] According to another aspect of the present invention, a tunnel segment is provided, which is obtained by casting with the tunnel segment mold described above.

[0010] According to another aspect of the present invention, a method for preparing a tunnel segment is provided, including: pouring concrete into the tunnel segment mold. When demolding, first remove the core rod, then take out the detachable part together with the segment body from the segment casting cavity, and finally take out the detachable part from the segment body to obtain the tunnel segment.

[0011] According to another aspect of the present invention, a method for constructing a tunnel segment is provided, including: splicing the tunnel segments at the construction position, setting connecting bolts in the bolt through holes through the bolt hand holes, connecting the adjacent tunnel segments, and pouring sealing concrete into the bolt hand holes to seal the bolt hand holes.

[0012] Furthermore, the method for pouring the sealing concrete into the bolt hand holes includes: first pouring bottom layer concrete into the bolt hand holes, and the depth of the bottom layer concrete is slightly higher than the position of the protruding part. Then pour upper layer concrete into the bolt hand holes. The bottom layer concrete includes cement, fine aggregate, coarse aggregate, water reducing agent and epoxy resin emulsion, and the upper layer concrete includes cement, steel fiber, fine aggregate, coarse aggregate and expansion agent.

[0013] Furthermore, after pouring the bottom layer concrete, vibrate it with a vibrator at a first frequency. After pouring the upper layer concrete, vibrate it with the vibrator at a second frequency, and the first frequency is less than the second frequency.

[0014] Further, first pour the bottom layer of concrete into the bolt manhole. The depth of the bottom layer of concrete is slightly higher than the position of the protruding part. The bottom layer of concrete includes cement, fine aggregate, coarse aggregate, water reducer, epoxy resin emulsion and an expansive agent of the same type as the upper layer of concrete. Subsequently, pour the upper layer of concrete into the bolt manhole. The upper layer of concrete includes cement, steel fiber, fine aggregate, coarse aggregate and an expansive agent. The volume fraction of the steel fiber is 0.5%-1.0%. Among them, the expansive agents of the bottom layer of concrete and the upper layer of concrete are of the same type. The dosage of the expansive agent in the bottom layer of concrete is 4%-6% of the total amount of cement, and the dosage of the expansive agent in the upper layer of concrete is 6%-8% of the total amount of cement.

[0015] Further, use a vibrating rod to vibrate at a first frequency, and the vibrating depth does not exceed 2 / 3 of the thickness of the bottom layer of concrete. After pouring the upper layer of concrete, use the vibrating rod to vibrate at a second frequency. The second frequency is 1.2-1.5 times the first frequency, and the vibrating depth extends 10-15 mm below the interface between the bottom layer of concrete and the upper layer of concrete to promote interface bonding. The first frequency is 8000-10000 times per minute, and the second frequency is 10000-12000 times per minute.

[0016] Further, the second frequency is 1.3 times the first frequency. When pouring the upper layer of concrete, the vibrating rod vibrates from bottom to top in a spiral path, and the vibrating depth extends 12 mm below the interface between the bottom layer of concrete and the upper layer of concrete. Among them, the first frequency is 9000 times per minute, and the second frequency is 11700 times per minute. The diameter of the vibrating rod is 25 mm, and the head of the vibrating rod is provided with an inverted conical protrusion with a height of 3 mm, which is used to locally extrude and compact the interface concrete during the vibrating process.

[0017] The present invention has at least the following beneficial effects: The mold of the present invention forms a groove inside the segment bolt manhole, so that a tenon is formed after the sealing concrete is cured, changing the existing method of simply relying on adhesive force to fix the sealing block. The mechanical engagement between the tenon and the groove greatly enhances the anchoring force of the sealing block in the bolt manhole, effectively avoiding the possibility of the sealing block falling off during the operation of the tunnel due to insufficient adhesive force, ensuring the integrity and safety of the tunnel structure, thereby improving the reliability of the tunnel structure and reducing the maintenance work requirements during the operation period. For projects such as water conveyance tunnels where maintenance is difficult, it reduces the occurrence probability of problems such as grid hole blockage, bolt corrosion and increased inner wall roughness caused by the falling off of the sealing block, reduces the water flow resistance, avoids local scouring, extends the service life of the tunnel, and ensures the efficient and stable water conveyance.

[0018] Other advantages, objects, and features of the present invention will be partly reflected by the following description, and partly will be understood by those skilled in the art through the research and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic structural diagram of an embodiment of the present application; Figure 2 It is an exploded view of a handhole die of an embodiment of the present application; Figure 3 It is an assembly schematic diagram of a handhole die of an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] The present invention will be further described in detail below with reference to the drawings, so that those skilled in the art can implement it according to the description in the specification.

[0021] It should be understood that terms such as "having", "comprising", and "including" used in the embodiments of the present application do not exclude the presence or addition of one or more other elements or their combinations. All directional indications (such as up, down, left, right, front, back...) in the embodiments of the present application are only used to explain the relative positional relationship and movement conditions between components in a specific posture. If the specific posture changes, the directional indication will also change accordingly. When an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or there may be an intermediate element at the same time. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or it can also be indirectly connected to the other element through an intermediate element. The descriptions in the embodiments of the present application related to "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features.

[0022] It should be noted that the technical solutions between the various embodiments of the present application can be combined with each other, but it must be based on the fact that those skilled in the art can implement them. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present application.

[0023] Embodiments of the present application provide a segment mold for preparing segments with bolt hand holes, including: a segment casting cavity 1 for casting the segment body; a core rod 3 with a pre-embedded sleeve sleeved outside, for forming a bolt through hole in the segment body; a hand hole mold 2, which includes a fixing part 201 and a detachable part 202, for forming a bolt hand hole (required for tightening bolts during segment assembly) communicating with the bolt through hole in the segment body. The fixing part 201 is arranged on the bottom surface of the segment casting cavity 1, and the detachable part 202 is detachably connected to the fixing part 201. A protruding part 204 protruding from the surface of the hand hole mold 2 is formed on the surface of the detachable part 202, for forming a groove on the inner surface of the bolt hand hole, so as to form a reliable mechanical bite between the bolt hand hole plugging concrete block and the bolt hand hole. Exemplarily, the segment casting cavity 1 includes an arc-shaped bottom plate 101, a pair of end plates 103 and a pair of side plates 102. The pair of end plates 103 and the pair of side plates 102 are arranged around the arc-shaped bottom plate 101 and together with the arc-shaped bottom plate 101 enclose a segment casting cavity 1 for casting the segment body. Its shape and size are customized according to the design requirements of the segment. The inner wall of the casting cavity 1 is smooth to ensure the flatness of the segment surface, and at the same time has sufficient strength and tightness to prevent slurry leakage during the concrete casting process.

[0024] Exemplarily, the core rod 3 is made of high-strength steel and is arranged in the casting cavity. One end is connected to the casting cavity and is detachable to ensure that it does not deform during the concrete casting and vibration processes. When the concrete is cast in the segment casting cavity 1, the core rod 3 and the pre-embedded sleeve work together to form a bolt through hole in the segment body. This hole is used for installing connecting bolts subsequently to achieve reliable connection of adjacent segments. Exemplarily, the arrangement of the core rod 3 and the hand hole mold 2 should ensure that the bolt through hole communicates with the bolt hand hole, which is convenient for setting connecting bolts in the bolt through hole to connect adjacent segments. The overall shape of the hand hole mold 2 should be smaller at the top and larger at the bottom, and the surface should be smooth to facilitate demolding. Exemplarily, the fixing part 201 is firmly arranged on the bottom surface of the segment casting cavity 1 and is integrally processed with the same high-strength steel as the segment casting cavity 1 to ensure its tight combination with the casting cavity 1 and overall stability. Exemplarily, a slot 203 is opened on the side of the fixing part 201. The setting method of the slot 203 only needs to ensure that the detachable part 202 can be smoothly detached from the fixing part 201 during the demolding process. Exemplarily, after the concrete is poured and solidified in the segment casting cavity 1, the protruding portions 204 on the surface of the detachable portion 202 form corresponding grooves on the inner surface of the bolt handhole. These grooves can enable the tenons formed after the sealing concrete is cured, and the grooves and tenons cooperate with each other to firmly embed the sealing block in the bolt handhole by mechanical biting. It mainly relies on the bonding force between the new and old concrete interfaces, overcoming the defect of mainly relying on the bonding force between the new and old concrete interfaces in the prior art; Exemplarily, the number of the slots 203 can be one or more, so as to set a plurality of detachable portions 202, and further a plurality of protruding portions 204 can be set, so as to form a plurality of grooves on the surface of the bolt handhole, and finally form a plurality of tenons on the surface of the sealing block, further enhancing the mechanical biting effect; It can be seen that the mold of this embodiment forms grooves inside the segment bolt handhole, so that the tenons are formed after the sealing concrete is cured, changing the way of simply relying on the bonding force to fix the sealing block in the prior art. The mechanical engagement between the tenons and the grooves greatly enhances the anchoring force of the sealing block in the bolt handhole, effectively avoiding the falling off of the sealing block due to insufficient bonding force during the operation of the tunnel, ensuring the integrity and safety of the tunnel structure; furthermore, for projects such as water conveyance tunnels with difficult maintenance, it reduces the occurrence probability of problems such as grid hole blockage, bolt corrosion and increase of inner wall roughness caused by the falling off of the sealing block, reduces the water flow resistance, avoids local scouring, extends the service life of the tunnel, and ensures the efficient and stable water conveyance.

[0025] In another embodiment, a slot 203 is provided on the side of the fixing portion 201, the extending direction of the slot 203 is along the direction in which the segment body is taken out from the segment casting cavity 1, the detachable portion 202 matches the shape of the slot 203, a magnet 205 is provided on one surface of the slot 203, and the detachable portion 202 is made of a ferromagnetic material; In this embodiment, the extending direction of the slot 203 is along the direction in which the segment body is taken out from the segment casting cavity 1, such as along the radial direction of the arc-shaped bottom plate 101. Such a design facilitates the smooth disassembly of the detachable portion 202 during the demolding process, avoiding the situation where the segment and the mold cannot be demolded; the detachable portion 202 is made of a ferromagnetic material, which can generate a strong adsorption force with the magnet 205 in the slot 203, so that the detachable portion 202 can be stably fixed in the slot 203 during the concrete pouring process, preventing it from shifting due to the impact force of the concrete.

[0026] In another embodiment, the slot 203 includes a bottom surface and at least two side surfaces, at least two of the side surfaces clamp the detachable portion 202, and the magnet 205 is provided on the bottom surface; In this embodiment, the slot 203 includes a bottom surface and at least two or more side surfaces, which play a role in accurately positioning and clamping the detachable portion 202, limiting the movement of the detachable portion 202 in a direction parallel to the segment during the casting process, ensuring that the detachable portion 202 will not shift during use. A high-performance magnet 205 is provided on the bottom surface of the slot 203, which limits the movement of the detachable portion 202 in a direction perpendicular to the segment during the casting process to a certain extent, ensuring that the detachable portion 202 will not detach from the fixed portion 201, thereby ensuring the casting quality of the segment.

[0027] In another embodiment, the protrusion gradually decreases in size from being close to the detachable portion 202 to being far away from the detachable portion 202, that is, a shape similar to a cone or a frustum is formed. This shape design helps the detachable portion 202 to be detached from the segment during the demolding process for reuse, and can be reused after being reinserted into the main body of the bolt hand hole mold 2 for the next round of segment production.

[0028] An embodiment of the present application also provides a tunnel segment, which is cast by the tunnel segment mold; using the mold of the above embodiment, a groove is formed inside the bolt hand hole of the segment of this embodiment, so that a tenon is formed after the sealing concrete is solidified, which changes the existing method of fixing the sealing block solely by relying on bonding force. The mechanical fit between the tenon and the groove greatly enhances the anchoring force of the sealing block in the bolt hand hole, effectively preventing the sealing block from falling off during tunnel operation due to insufficient bonding force.

[0029] The embodiment of the present application further provides a method for preparing a tunnel segment, comprising: pouring concrete into the tunnel segment mold, and when demolding, first removing the core rod 3, then taking the detachable portion 202 out of the segment casting cavity 1 together with the segment body, and finally taking the detachable portion 202 out of the segment body to obtain a tunnel segment; Specifically, concrete that meets the design requirements is slowly and evenly poured into the segment casting cavity 1 of the tunnel segment mold through professional pouring equipment; during the pouring process, close attention is paid to the fluidity and filling of the concrete to ensure that the concrete fully fills every corner of the segment casting cavity 1, especially around the core rod 3 and the hand hole mold 2, to avoid voids or looseness; Then, after the concrete reaches a certain strength (determined by on-site test block detection), the core rod 3 is first removed. During the removal process, a special core rod 3 removal tool is used to smoothly pull out the core rod 3 along the axial direction of the core rod 3; after the core rod 3 is removed, the detachable portion 202 is taken out from the segment casting cavity 1 together with the segment body. Due to the matching design between the detachable portion 202 and the slot 203 and the adsorption effect of the magnet 205, during the demoulding process, the detachable portion 202 can maintain a relatively stable positional relationship with the segment body and can be smoothly taken out from the segment casting cavity 1; Finally, by utilizing the detachable connection between the detachable part 202 and the fixed part 201, the detachable part 202 is removed from the segment body by appropriate external force (such as lightly tapping or using a small disassembly tool), thereby obtaining a complete tunnel segment with bolt through holes and specific bolt hand holes; the detachable part 202 is collected and inserted into the slot 203 of the fixed part 201 to prepare for the production of the next segment.

[0030] The embodiment of the present application further provides a tunnel segment construction method, comprising: splicing the tunnel segments at a construction position, setting connecting bolts in the bolt through holes through the bolt hand holes, connecting adjacent tunnel segments, and pouring sealing concrete into the bolt hand holes to seal the bolt hand holes; Specifically, the prepared tunnel segments are transported to the construction site and spliced ​​according to the design requirements and construction specifications. During the splicing process, professional lifting equipment is used to accurately lift the segments to the designated locations, and the adjacent tunnel segments are accurately aligned and preliminarily fixed through the preset positioning devices and connection structures on the segments. Then, through the bolt hand holes on the segments, connecting bolts are installed in the bolt through holes to firmly connect the adjacent tunnel segments. When installing the bolts, a torque wrench is used to tighten them according to the specified torque value to ensure the reliability of the bolt connection and form a tight overall structure between the adjacent segments. Finally, pour sealing concrete into the bolt hand holes to seal the bolt hand holes to prevent corrosion to the bolts caused by external factors, while ensuring the sealing and aesthetics of the interior of the tunnel.

[0031] In order to further improve the stability of the blocking block, in this embodiment, when pouring the blocking concrete, suitable concrete materials are selected according to the characteristics and usage requirements of the bolt hand holes. The bottom concrete can be made of cement, fine aggregate, coarse aggregate, water reducer, epoxy resin emulsion and ettringite expansion agent, wherein the expansion agent dosage can be 4%, 5% or 6% of the total cement amount, the fine aggregate can be medium sand with a fineness modulus of 2.6-2.8, the coarse aggregate can be 5-10mm continuously graded crushed stone, the epoxy resin emulsion can be epoxy E-44 type, and the expansion agent can be Shanxi Huangteng HCSA type.

[0032] For the upper-layer concrete, cement, steel fibers, fine aggregates, coarse aggregates, and calcium aluminate-based expansive agents can be selected. The volume fraction of steel fibers can be 0.5%, 0.75%, or 1.0%, and the dosage of the expansive agent can be 6%, 7%, or 8% of the total amount of cement. The steel fibers can be copper-plated steel fibers with a length of 15 mm and a diameter of 0.2 mm. The pouring depth of the bottom-layer concrete can be controlled to be 2-3 mm higher than the position of the protrusion. The upper-layer concrete is poured before the bottom layer starts to set, and the mixing time is not less than 3 minutes. The bottom-layer concrete is mainly used for tightly bonding with the inner wall of the segment manhole, especially for enhancing the bonding between the formed tenons and grooves, and enhancing the overall stability. The upper-layer concrete focuses on improving the strength and crack resistance of the plugging block. By coordinating the type and dosage of the expansive agent, the interface cracking rate is reduced from 5%-8% of the traditional method to less than 1%. Combining with the mechanical interlocking structure, the shedding rate of the plugging concrete block is reduced from 8%-12% of the traditional method without mechanical interlocking to less than 0.3%, and the pull-out force is increased from 15-20 kN of the traditional method to ≥100 kN. After testing, compared with the concrete composed of ordinary cement, fine aggregates, and coarse aggregates, the plugging effect is better, the stability of the plugging block is better, and it is less likely to fall off; In another embodiment, a high-frequency inserted vibrator can be selected, such as the German Wacker Neuson IREN 38 type with a diameter of 25-30 mm, and the vibration depth is controlled by the scale marks on the vibrator. The first frequency can be selected from 8000, 9000, or 10000 times / minute, the second frequency can be selected from 10000, 11000, or 12000 times / minute, and the second frequency is 1.2, 1.3, or 1.5 times that of the first frequency. The vibration depth of the bottom-layer concrete does not exceed 2 / 3 of its thickness. When vibrating the upper-layer concrete, the insertion depth of the vibrator extends 10, 12, or 15 mm below the interface. During operation, the vibrator is vertically inserted into the concrete, the spacing between the insertion points is 15 cm, and the vibration time for each hole is 15-20 seconds. Compared with the method that only relies on mechanical interlocking (shedding rate of 2%-3%), this process strengthens the bonding through interface vibration, increasing the interface bonding strength from 60-70 kN of only mechanical interlocking to more than 100 kN, and further reducing the shedding rate of the plugging block to less than 0.3%.

[0033] In another embodiment, an inverted cone-shaped protrusion can be added to the head of the vibrating rod. The cross-section of the protrusion is circular, and the diameter gradually increases from the root (connection with the vibrating rod) to the top, forming an inverted cone structure with "wide top and narrow bottom" (similar to a mushroom umbrella shape). The protrusion height is 3mm, and the material is cemented carbide. The protrusions are evenly distributed along the circumference of the vibrating rod head, and the diameter of the vibrating rod is 25mm. The first frequency is fixed at 9000 times / minute, and the second frequency is 11700 times / minute. The vibration depth extends to 12mm below the interface, and the error is controlled within ±2mm. During operation, the vibrating rod moves upward in a clockwise spiral from the bottom of the bolt hand hole, and rotates 30° for every 10mm of movement. The inverted cone-shaped protrusion on the head of the vibrating rod forms a radial extrusion on the concrete during rotation. The spacing between the inverted cone-shaped protrusions is 5mm. After the vibration is completed, the surface is smoothed. This design enables the interface to form a serrated dense structure, with a density that is 30% higher than the traditional method, the interface bonding strength is increased to 120kN, and the sealing block fall-off rate is stabilized at less than 0.1%. Compared with the method without mechanical bite (8%-12%) and the method with only mechanical bite (2%-3%), the overall performance is significantly optimized.

[0034] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes, and they can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A tunnel segment mould, used for preparing segments with bolt hand holes, characterized in that: include: The segment casting cavity is used to cast the segment body; A mandrel, the outer surface of which is provided with an embedded sleeve, for forming a bolt through hole in the segment body; A hand hole mold comprises a fixed portion and a detachable portion, and is used to form a bolt hand hole in the segment body that is connected to the bolt through hole. The fixed portion is arranged on the bottom surface of the segment casting cavity, and the detachable portion is detachably connected to the fixed portion. A protrusion is formed on the surface of the detachable portion, which is used to form a groove on the inner surface of the bolt hand hole.

2. The tunnel segment mold according to claim 1, characterized in that: A slot is provided on the side of the fixing portion, and the extending direction of the slot is along the direction in which the segment body is taken out of the segment casting cavity. The detachable portion matches the shape of the slot, and a magnet is provided on one surface of the slot. The detachable portion is made of ferromagnetic material.

3. The tunnel segment mold according to claim 2, characterized in that: The slot includes a bottom surface and at least two side surfaces, at least two of the side surfaces clamp the detachable portion, and the magnet is disposed on the bottom surface.

4. The tunnel segment mold according to claim 1, characterized in that: The size of the protruding portion gradually decreases from being close to the detachable portion to being far away from the detachable portion.

5. Tunnel segment, characterized in that: It is obtained by casting the tunnel segment mold described in any one of claims 1-4.

6. A method for preparing a tunnel segment, characterized in that: include: Concrete is poured into the tunnel segment mold according to claim 1. When demolding, the core rod is first removed, and then the detachable part is taken out from the segment casting cavity together with the segment body, and finally the detachable part is taken out from the segment body to obtain the tunnel segment.

7. A tunnel segment construction method, characterized in that: include: The tunnel segments described in claim 5 are spliced ​​at the construction site, connecting bolts are arranged in the bolt through holes through the bolt hand holes, adjacent tunnel segments are connected, and sealing concrete is poured into the bolt hand holes to seal the bolt hand holes.

8. The tunnel segment construction method according to claim 7, characterized in that: First, pouring a bottom layer of concrete into the bolt hand hole, wherein the depth of the bottom layer of concrete is slightly higher than the position of the protruding portion, and the bottom layer of concrete includes cement, fine aggregate, coarse aggregate, water reducing agent, epoxy resin emulsion and an expansion agent of the same type as the upper layer of concrete; then pouring an upper layer of concrete into the bolt hand hole, wherein the upper layer of concrete includes cement, steel fiber, fine aggregate, coarse aggregate and an expansion agent, and the volume content of the steel fiber is 0.5%-1.0%; The expansive agent of the bottom concrete and the upper concrete is of the same type, and the amount of the expansive agent of the bottom concrete is 4%-6% of the total amount of cement, and the amount of the expansive agent of the upper concrete is 6%-8% of the total amount of cement.

9. The tunnel segment construction method according to claim 8, characterized in that: Vibrating with a vibrating rod at a first frequency, the vibration depth not exceeding 2 / 3 of the thickness of the bottom concrete; after pouring the upper concrete layer, vibrating with the vibrating rod at a second frequency, the second frequency being 1.2-1.5 times the first frequency, and the vibration depth extending to 10-15 mm below the interface between the bottom concrete and the upper concrete layer, so as to promote interface bonding; The first frequency is 8000-10000 times / minute, and the second frequency is 10000-12000 times / minute.

10. The tunnel segment construction method according to claim 9, characterized in that: The second frequency is 1.3 times the first frequency, and the vibrating rod vibrates from bottom to top in a spiral path when pouring the upper layer of concrete, and the vibration depth extends to 12 mm below the interface between the bottom layer of concrete and the upper layer of concrete; Wherein, the first frequency is 9000 times / minute, and the second frequency is 11700 times / minute; The diameter of the vibrating rod is 25 mm, and the head of the vibrating rod is provided with an inverted cone-shaped protrusion with a height of 3 mm, which is used to form local compression and compaction on the interface concrete during the vibration process.

Images