Ultra-high-performance concrete structure based on prestress cable penetrating and construction method of ultra-high-performance concrete structure

Abstract

The invention discloses an ultra-high performance concrete structure based on prestress cable penetrating and a construction method thereof, and relates to the field of hole body supporting and reinforcing engineering. The concrete structure is arranged along the circumferential direction of a hole body in a wall-attached mode and is composed of a prefabricated pipe piece system, a prestress system and a concrete system. Cable grooves are formed in the wall-attached sides of the duct pieces, cable penetrating holes are formed in the end faces of the duct pieces, and the prestressed cable bodies are tensioned and anchored after penetrating across the duct pieces; a back concrete filling layer is formed between the duct piece and the hole body, and a concrete inverted arch or abutment is arranged at the lower part; the construction method comprises the steps of wall attaching assembly, synchronous cable penetrating, graded tensioning, back pouring and concrete inverted arch pouring. The prestressed cable bodies replace traditional circumferential bolt connection, and a continuous circumferential stress and wall-attached force transfer path is constructed, so that circumferential seam openings and relative slippage are reduced, circumferential internal force distribution is improved, the overall rigidity, water tightness and durability of the structure are improved, and the prestressed cable is suitable for newly-built and existing hole bodies.

Description

Technical Field

[0001] This application relates to the field of tunnel support and reinforcement engineering, specifically to an ultra-high performance concrete structure based on prestressed cable threading and its construction method. Background Technology

[0002] Ultra-high performance concrete (UHPC) possesses high strength, high toughness, density, durability, and impermeability, making it suitable for the construction and reinforcement of structures such as tunnels, utility tunnels, and culverts. In new construction projects, UHPC is often fabricated as precast lining panels or segments, assembled into rings by tenon / mortise joints, adhesive grooves, and end face connections. In the reinforcement of existing structures, UHPC can be used as lining replacement or local reinforcement components, forming a wall-attached force transfer with the original lining through back grouting or casting, thereby achieving rapid construction and improved durability within limited clearance.

[0003] Under the influence of confining pressure, water pressure, operational loads, and temperature differences, circumferential joints typically bear a combination of circumferential axial force, bending moment, and shear force, making them highly sensitive to connection continuity and wall adhesion quality. However, traditional UHPC precast segment systems often use end-face bolt connections in the circumferential direction, which has the following structural limitations: First, the bolts are discrete point connections, resulting in a "point-to-plate" force transmission path in the circumferential direction, leading to insufficient overall stiffness and continuity; when subjected to bending moment and shear force, stress concentration and abrupt stiffness changes easily occur near the joint. Second, openings weaken the cross-section, and the coaxiality of the hole positions, assembly tolerances, and preload are inconsistent, easily leading to misalignment and uneven joint width, affecting the compression and watertightness of the sealing strip; under the action of axial force and bending moment, the local compressive-tensile stress concentration at the hole edge is more prominent. Third, back grouting is a blind grouting method, constrained by hole positions and venting conditions, making it difficult to ensure continuous wall adhesion throughout the circumference; uneven wall adhesion leads to uneven distribution of circumferential axial force and bending moment, increasing additional deformation at the joint. Fourth, the construction process involves many steps, and the preload of bolts decreases and corrodes over long-term service, reducing the joint's resistance to slippage and tension, thus increasing the risk of leakage.

[0004] The aforementioned issues collectively constrain the integrity and durability of traditional UHPC assembly systems under high load and rapid construction conditions.

[0005] Application content

[0006] This application proposes an ultra-high performance concrete structure based on prestressed cable threading and its construction method, which solves the problems in the prior art.

[0007] To achieve the above objectives, the technical solution proposed in this application is as follows:

[0008] In the first aspect, this application provides an ultra-high performance concrete structure based on prestressed cable threading, which is installed along the circumferential wall of the tunnel body on the inner side of the tunnel body, including a precast segment system, a prestressing system and a concrete system;

[0009] The precast segment system is composed of multiple precast segment units connected sequentially in the circumferential direction. At least one cable groove is provided in the circumferential direction on the wall-attached side of the precast segment unit, and cable through holes communicating with the cable groove are provided at both ends of the precast segment unit.

[0010] The prestressed system includes prestressed cables arranged along the cable groove. The prestressed cables pass through the cable holes of adjacent precast segment units in sequence. After being tensioned, the two ends of the prestressed cables are fixed to the anchors of the anchoring mechanism and are in a prestressed tension state.

[0011] The concrete system includes a back concrete filling layer disposed between the precast segment unit and the tunnel body, the back concrete filling layer making the precast segment system, the prestressed system and the tunnel body adhere to the wall and be solidified together.

[0012] Furthermore, the concrete system also includes a concrete invert or foundation set at the lower part of the tunnel body, the concrete invert or foundation being fixedly connected to the precast segment system and the tunnel body.

[0013] Furthermore, the precast segment is formed by several precast segment units surrounding a ring structure with reserved assembly gaps. A capping segment unit is set at the reserved assembly gap, and the capping segment unit is connected to the end face of the adjacent precast segment unit to achieve circumferential closure.

[0014] Furthermore, it includes an arc-shaped segment body, which is precast integrally from ultra-high performance concrete, and the segment body has a wall-attached side and an opposing cavity side.

[0015] At least one cable groove is provided circumferentially on the wall-attached side. The cable groove extends from the bottom end to the top end of the segment body. Cable through holes are provided at both ends of the cable groove, and the cable through holes are respectively provided on the top and bottom end faces of the segment body.

[0016] The segment body is provided with grouting holes that communicate with the cable groove; several transverse connecting bolt holes are provided on the side of the cavity; tenons or mortises are provided at the top, bottom and side ends of the segment body respectively.

[0017] Furthermore, a plurality of guide cable limiting platforms are provided at intervals along the length of the cable groove; the guide cable limiting platforms are fixed to the bottom of the cable groove, and a semi-circular groove is provided at the upper end of the guide cable limiting platforms.

[0018] Furthermore, the prestressed cable body includes reinforcing cables, steel strands, single high-strength steel wires, parallel steel wire bundles, or fiber-reinforced composite material cables.

[0019] Furthermore, the cross-sectional shape of the cable groove is arc-shaped, U-shaped, trapezoidal, or rectangular.

[0020] Furthermore, the cable groove is provided in three sections, and each section has two sets of guide cable limiting platforms.

[0021] Furthermore, each precast segment unit has three pairs of transverse connecting bolt holes, symmetrically located at the upper, middle, and lower parts of the segment body. Adjacent precast segment units along the tunnel extension direction are connected by arc-shaped bolts passing through the transverse connecting bolt holes.

[0022] Furthermore, continuous pressure grooves are provided at the top, bottom and both sides of the tube segment body, and water-stop strips or sealant are provided in the pressure grooves.

[0023] Secondly, this application provides a construction method for ultra-high performance concrete structures based on prestressed cable threading, comprising the following steps:

[0024] a) To construct and repair the foundation of newly excavated tunnels, or to clean, level and treat the interface of the inner foundation of existing tunnels.

[0025] b) Assemble multiple precast tunnel segments sequentially along the circumference of the tunnel body, with the tenons and mortises on the top and bottom ends of adjacent precast tunnel segments fitting together to form a ring of precast tunnel segments arranged circumferentially.

[0026] c) During the circumferential assembly process of step b), prestressed cables are simultaneously threaded through each cable groove, so that the prestressed cables pass through the cable holes of adjacent precast segment units in sequence, and form exposed sections outside the precast segment system.

[0027] d) The exposed section of the prestressed cable is tensioned in stages using a tensioning device until the design prestress value is reached, and the cable head is anchored by an anchoring mechanism to put the prestressed cable in a prestressed tension state.

[0028] e) Through the grouting holes on the precast segment unit, the back concrete filling layer is poured from bottom to top, and the back concrete filling layer is integrally bonded to the precast segment system, prestressed cable body and the tunnel wall.

[0029] f) Cut off excess prestressed cables and remove the tensioning device.

[0030] Furthermore, after completing step d), the capping segment unit is installed at the circumferentially reserved assembly gap, so that the prefabricated segment system achieves circumferential closure.

[0031] Furthermore, a concrete invert or foundation is provided at the lower part of the tunnel body, and the lower end of the precast segment system and the anchoring mechanism are cast and fixed to the concrete invert or foundation.

[0032] Compared with the prior art, the beneficial effects of this application are:

[0033] The precast tunnel segments in this application feature circumferential cable grooves and through-holes on the wall-attached side. Prestressed cables are continuously arranged across segments and tensioned by an anchoring mechanism, ensuring continuous tension and constraint of the circumferential joints under axial force, bending moment, and shear force. This reduces joint opening and relative slippage, while simultaneously meeting load-bearing and waterproofing requirements. The absence of bolt holes in the circumferential direction avoids localized weakening and stress concentration caused by point connections, maintaining the effective cross-section and overall stiffness continuity of the ultra-high performance concrete. Cable guides stabilize the cable alignment within the cable grooves, reducing the risk of cable torsion and deflection, and facilitating cable force control. Pressure grooves, combined with waterstop strips or sealant, enhance the consistency and durability of joint sealing. The prestressed cables, after tensioning and fixed by the anchoring mechanism and end-cast locking bodies, and after the hardening of the back concrete filling layer, together with the precast tunnel segment units and the underlying concrete invert arch or foundation and cavities, form a circumferential prestressed wall-attached closed load-bearing ring, improving the overall integrity, stiffness, and durability of the structure.

[0034] This application's method employs a series of processes: wall-mounted assembly, synchronous cable threading, staged tensioning, and backfilling. Circumferential assembly relies on the initial positioning and fit of the tenon and mortise before the cable is threaded through to achieve prestressed constraint, eliminating the need for circumferential bolts and reducing assembly errors and uneven sealing caused by misalignment and pre-tightening. Synchronous cable threading is performed simultaneously with assembly, facilitating control of the cable trajectory and exposed end length, reducing relocation and secondary operations. Staged tensioning is controlled by dual parameters of tension force and elongation, anchoring at design values, and ensuring controllable circumferential internal force distribution. Backfilling with concrete is implemented from bottom to top through grouting holes, with clear venting and filling paths, facilitating the formation of a continuous wall-mounted layer. Compared to traditional multi-segment bolting, this method achieves circumferential constraint through single or group tensioning, resulting in fewer processes and shorter construction time. Furthermore, key operations are completed on the tunnel side, making equipment layout and traffic organization more convenient, suitable for confined space construction in newly excavated and existing tunnels.

[0035] Of course, implementing the various technical solutions of this application does not necessarily require achieving all of the advantages described above at the same time. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of this application 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 this application. For those skilled in the art, other embodiments can be obtained from these drawings without creative effort.

[0037] Figures 1-5 This is a schematic diagram of the construction method according to an embodiment of this application;

[0038] Figure 6 This is a schematic diagram of the structure of the precast segment unit attached to the wall in an embodiment of this application;

[0039] Figure 7 This is a schematic diagram of the structure of the precast segment unit cavity side in an embodiment of this application;

[0040] Figure 8 This is a schematic diagram of the end structure of the precast segment unit in an embodiment of this application;

[0041] Figure 9 This is a schematic diagram of the tensioning process of the tensioning support according to an embodiment of this application;

[0042] Figure 10 This is a flowchart illustrating the method of an embodiment of this application;

[0043] In the figure, 1-precast segment unit, 101-segment body, 102-cable groove, 103-cable through hole, 104-grouting hole, 105-lateral connecting bolt hole, 106-tenon, 107-tenon groove, 108-guide cable limiting platform, 109-pressing groove.

[0044] 2-Prestressed steel cable;

[0045] 3- Concrete filling layer behind;

[0046] 4-Tensioning support, 401-Guide dividing column, 402-Extension plate, 403-Conical anchor head, 404-Horizontal guide frame, 405-Guide horizontal shaft, 406-Triangular stiffening plate, 407-Tensioning device mounting base, 408-Cable threading guide hole, 409-Jack, 410-Reaction beam;

[0047] 5-End casting locking body;

[0048] 6- Concrete inverted arch. Detailed Implementation

[0049] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0050] In the description of this patent, it should be understood that the terms “center,” “upper,” “lower,” “front,” “back,” “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 used only for the convenience of describing this patent 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 patent.

[0051] In the description of this patent, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection or setting, a detachable connection or setting, or an integral connection or setting. Those skilled in the art can understand the specific meaning of the above terms in this patent according to the specific circumstances.

[0052] Example 1:

[0053] See Figures 1-5 This embodiment provides a construction method for ultra-high performance concrete structures based on prestressed cable threading, see [link to relevant documentation]. Figure 10 It includes the following steps:

[0054] Step S1: Perform tunneling and base surface repair on newly excavated tunnels, or clean, level and treat the interface of the inner base surface of existing tunnels; remove seepage points, loose blocks and residues before construction, and set up temporary drainage and local leveling if necessary, so that the subsequent wall assembly meets the flatness and cleanliness requirements.

[0055] Step S2: Assemble multiple precast tunnel segment units 1 sequentially along the circumference of the tunnel body, attaching them to the wall. Each precast tunnel segment unit 1 includes a segment body 101 precast as a whole from ultra-high performance concrete. The segment body 101 has a wall-attached side and an opposite cavity side. The top and bottom end faces of adjacent precast tunnel segment units 1 are positioned by tenon 106 and tenon groove 107. Water-stopping material is simultaneously embedded in the pressure groove 109 to form an end face seal, thereby forming a ring of precast tunnel segments arranged circumferentially.

[0056] Step S3: During the circumferential assembly process described above, prestressed steel cables 2 are simultaneously threaded through the cable grooves 102 provided along the wall side. The prestressed steel cables 2 sequentially pass through the cable-passing holes 103 of adjacent precast segment units 1, and are positioned and limited within the cable grooves 102 by guide cable limiting platforms 108. Multiple sets of guide cable limiting platforms 108 are fixed at intervals to the bottom of the cable grooves 102. A semi-circular groove is provided at the upper end of the guide cable limiting platform 108 to support the prestressed steel cables 2. After the prestressed steel cables 2 are threaded, an exposed section for tensioning is reserved outside the precast segment system.

[0057] Step S4: Subsequently, a set of tensioning supports 4 are set at both ends of the prestressed steel cable 2 to implement graded tensioning and anchoring. In this embodiment, tensioning is organized in a symmetrical or zoned sequence, and controlled by dual parameters of tension force and elongation. After each stage of tensioning, the pressure is stabilized and the elongation is re-measured. If under-tension occurs, additional tension is applied. After reaching the design prestress value, the cable head is anchored by mechanical anchors, so that multiple prestressed steel cables 2 are simultaneously under prestressed tension.

[0058] Step S5: After tensioning and anchoring are completed, formwork is erected and cast inside the tensioning support 4 to form the end casting locking body 5; the end casting locking body 5 is fixed together with the end head of the prestressed steel cable 2 to maintain the overall stability of the prestress and the structure; then the prestressed steel cable 2 other than the end casting locking body 5 is cut off, and the tensioning support 4 and other temporary fixtures are removed.

[0059] Step S6: Pour the back concrete filling layer 3 from bottom to top through the grouting holes 104 on the precast segment unit 1; during construction, organize the air venting and observe the overflow of grout in sections and compartments until it is full and dense; after curing to the design strength, make the back concrete filling layer 3, the segment body 101, the prestressed steel cable 2 and the tunnel wall bonded together to form a continuous support lining along the circumference.

[0060] Step S7: In this embodiment, a concrete invert arch 6 is installed at the lower part of the tunnel. The lower and end locking bodies 5 of the precast segment unit 1 are cast and fixed to the concrete invert arch 6 to improve the bearing constraint and overall stability. The concrete filling layer 3 behind can be poured in one go or implemented in stages according to sections. For new projects, it is advisable to pour concrete as it is installed. When the existing tunnel or working surface is limited, it can be poured in a unified manner after tensioning and anchoring in several sections, and the construction of the concrete invert arch 6 should be coordinated to ensure continuous wall adhesion and linear control. In other embodiments, the invert arch can be replaced by abutments on both sides, preferably continuous strip abutments extending along the tunnel.

[0061] After a ring of precast tunnel segments has been assembled, threaded, tensioned, anchored, and fixed to the wall according to steps S2-S6, if it is necessary to continue construction along the extension direction of the tunnel, the precast tunnel segment units of two adjacent rings are bolted together by arc bolts configured in their corresponding transverse connecting bolt holes 105, so as to achieve structural connection and linear continuity along the tunnel direction; this bolting only undertakes the connection and positioning function along the extension direction of the tunnel and does not participate in the circumferential assembly stress.

[0062] See Figure 9In this embodiment, the tensioning support 4 includes guide partition columns 401, extension clamping plates 402, conical anchor heads 403, horizontal guide frames 404, guide horizontal shafts 405, triangular stiffening plates 406, tensioning device mounting bases 407, cable threading guide holes 408, jacks 409, and reaction beams 410. The extension clamping plates 402 are mounted on the guide partition columns 401 and located on the side closest to the precast segment unit 1. Two sets of extension clamping plates 402 form a clamping jaws, used to clamp and limit the edge parts of the precast segment unit 1, preventing relative displacement and rotation of the segments during tensioning. The guide partition columns 401 are spaced laterally to form several parallel guide channels; multiple guide partition columns 401 are connected by guide horizontal shafts 405, which are used to change the direction of multiple prestressed steel cables 2. The tensioning device mounting base 407 is arranged facing the reaction side, and a cable threading guide hole 408 is opened on it. The cable threading guide hole 408 corresponds one-to-one with the guide channel formed by the guide partition column 401. The reaction beam 410 is mounted on two horizontal guide frames 404 and can slide. The jack 409 is arranged on the tensioning device mounting base 407. The output end of the jack 409 is connected to the reaction beam 410. The triangular stiffening plate 406 is set at the key connection to improve the overall stiffness and reaction force transmission stability. The conical anchor head 403 is used to pre-fix the cable end after cable threading.

[0063] The working process of tension support 4 is as follows: the prestressed steel cable 2 is led out from the cable-passing hole 103 of the precast segment unit 1, passes through the guide channel between the guide partition column 401 in sequence, goes around the guide horizontal axis 405 from below, and passes laterally through the cable-passing guide hole 408 and the locking hole on the reaction beam 410 in sequence, and is pre-fixed by the conical anchor head 403; next, two sets of jacks 409 push the reaction beam 410 to move along the horizontal guide frame 404, apply tension force to multiple prestressed steel cables 2, and after multiple stages of tensioning, the cable head is anchored by mechanical anchors, so that multiple prestressed steel cables 2 are simultaneously in the prestressed tension state.

[0064] Example 2:

[0065] The difference from Example 1 is that this example involves circumferential closed assembly construction, ultimately completing a single-ring circumferential closed structure. Specifically, after completing the wall-mounted assembly of S1–S4, synchronous cable threading, graded tensioning, and cable shearing and fixing, the capping segment units are installed at the pre-reserved circumferential assembly gaps. The installation method can refer to existing precast segment capping assembly processes (such as the wedge-shaped capping segment jacking method). After the capping segment units are installed, the back concrete filling layer is poured from bottom to top through the grouting holes and cured to the design strength.

[0066] Example 3:

[0067] See Figures 1-5This embodiment provides an ultra-high performance concrete structure based on prestressed cable threading, specifically an inverted arch UHPC configuration.

[0068] The structure is installed along the circumference of the tunnel wall inside the tunnel and includes a precast segment system formed by multiple precast segment units 1, prestressed steel cables 2 arranged along the cable grooves 102 of the precast segment system, a back concrete filling layer 3 set between the precast segment unit 1 and the tunnel, and a concrete invert arch 6 arranged at the bottom of the tunnel.

[0069] See Figures 6-8 The single-piece precast tunnel segment unit 1 is integrally precast from ultra-high performance concrete, and its segment body 101 has a wall-attached side and an opposing cavity side. Multiple cable grooves 102 are arranged circumferentially on the wall-attached side, extending from the bottom to the top of the segment body 101. Cable-passing holes 103 communicating with the cable grooves 102 are respectively opened on the top and bottom end faces of the segment body 101. Cable guide and limiting platforms 108 are spaced apart along the length of the cable grooves 102, with multiple sets of guide and limiting platforms 108 arranged at the bottom of the cable grooves 102, their upper ends forming semi-circular grooves to accommodate and limit the prestressed steel cables 2. The segment body 101 is equipped with... The grouting hole 104, which is connected to the cable groove 102, is provided with a transverse connecting bolt hole 105 on the cavity side. The top, bottom and side ends of the segment body 101 are respectively provided with tenons 106 or tenons 107. The top, bottom and side ends of the segment body 101 are continuously provided with pressure grooves 109 to cooperate with the water-stopping material. The end faces of adjacent precast segment units 1 are positioned by the tenons 106 and the tenons 107 for easy installation. The pressure grooves 109 are filled with sealing material to form an end face seal.

[0070] Multiple prestressed steel cables 2 are threaded along each cable groove 102. Each prestressed steel cable 2 sequentially passes through the cable hole 103 of the adjacent precast segment unit 1. In the final state, both ends of the prestressed steel cable 2 extend out of the precast segment and are fixed by the anchoring mechanism and are in a prestressed tension state. In this embodiment, each prestressed steel cable 2 is provided with a mechanical anchor as an anchoring mechanism at its end. The mechanical anchor is finally cast into the end casting locking body 5. The end casting locking body 5 is cast integrally with the concrete invert arch 6, so that the lower edge of the precast segment unit 1, the prestressed steel cable 2 and its mechanical anchor, the end casting locking body 5 and the concrete invert arch 6 are fixed together as one.

[0071] The concrete filling layer 3 behind is filled between the precast segment unit 1 and the tunnel. The concrete filling layer 3 behind fills the cable groove 102 and the wall space between the precast segment unit 1 and the tunnel, and finally is integrated with the segment body 101, the prestressed steel cable 2 and the tunnel wall.

[0072] In this embodiment, the single precast segment unit 1 has three cable grooves 102, and each cable groove 102 has two sets of guide cable limiting platforms 108. The single precast segment unit 1 has three pairs of transverse connecting bolt holes 105, which are symmetrically arranged on the upper, middle and lower parts of the cavity side of the segment body 101. Along the extension direction of the cavity, adjacent rings of precast segments can be bolted together by configuring arc bolts in the corresponding transverse connecting bolt holes 105 of the precast segment unit 1 to form a structural connection and continuity in the extension direction of the cavity.

[0073] The concrete structure described in this embodiment is suitable for the reinforcement and renovation of the linings of existing tunnels, utility tunnels, and municipal / hydraulic tunnels.

[0074] In this embodiment, the back concrete filling layer 3, the concrete invert arch 6, and the end-cast locking body 5 are made of fine aggregate concrete, which has good fluidity and pumpability, high bonding performance, low shrinkage, and good impermeability and durability. This facilitates filling the troughs and connecting voids, forming a reliable stress transfer path. In other embodiments, the concrete filling layer can be made of cement-based grouting material, ultrafine cement slurry, shotcrete, epoxy mortar, or polymer-modified mortar, with the layer thickness, early strength requirements, and environmental durability configured accordingly.

[0075] In this embodiment, the prestressed steel cable 2 is made of steel strand, which has the characteristics of high tensile strength, low relaxation, good flexibility, high efficiency in cable threading and tensioning, and mature compatibility with commonly used mechanical anchors; in other embodiments, the cable body can be made of materials such as steel bar cable, single high-strength steel wire, parallel steel wire bundle or fiber reinforced composite material cable.

[0076] The above arrangement makes the prestress transmission path of the prestressed steel cable 2 clear and the anchorage stiffness high, which can effectively reduce the prestress loss caused by displacement and relaxation. When working together with the concrete filling layer 3 behind it, the structure forms a continuous force path in the circumference and closes with the lower bearing (base or invert arch), which helps to suppress the opening of the end face joint and uneven deformation, and improve the overall stiffness and watertight durability. At the same time, the construction process is concentrated on the cavity side, which facilitates the organization of assembly and quality control in the confined space.

[0077] In other embodiments, prefabricated segments have pre-reserved assembly gaps in the circumference (preferably located at the arch or top), and capping segment units are installed in the gaps. The end faces of the capping segment units can be wedge-shaped or trapezoidal. During installation, a lifting device is arranged on the side of the cavity, and the capping segment units are sent into the gaps according to the capping assembly process such as "jacking in". After the capping is in place, the end faces are positioned by the engagement of tenons and mortises, and water-stopping material is pre-placed in the pressure groove to complete the end face sealing, thus completing the circumferential closure; it is suitable for the ring formation of the inner lining of newly built tunnels and culverts.

[0078] For those skilled in the art, several improvements and modifications can be made without departing from the principles to which this application pertains, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A high-performance concrete structure based on prestressed cables, installed along the circumferential wall of the tunnel body on the inner side of the tunnel, characterized in that, Including precast tunnel segments, prestressed systems, and concrete systems; The precast segment system is composed of multiple precast segment units connected sequentially in the circumferential direction. At least one cable groove is provided in the circumferential direction on the wall-attached side of the precast segment unit, and cable through holes communicating with the cable groove are provided at both ends of the precast segment unit. The prestressed system includes prestressed cables arranged along the cable groove. The prestressed cables pass through the cable holes of adjacent precast segment units in sequence. After being tensioned, the two ends of the prestressed cables are fixed to the anchors of the anchoring mechanism and are in a prestressed tension state. The concrete system includes a back concrete filling layer disposed between the precast segment unit and the tunnel body, the back concrete filling layer making the precast segment system, the prestressed system and the tunnel body adhere to the wall and be solidified together.

2. The ultra-high performance concrete structure based on prestressed cable as described in claim 1, characterized in that, The concrete system also includes a concrete invert or foundation set at the bottom of the tunnel, and the concrete invert or foundation is fixedly connected to the precast segment system and the tunnel.

3. The ultra-high performance concrete structure based on prestressed cable as described in claim 1, characterized in that, The precast segment is a ring structure formed by several precast segment units circumferentially. A capping segment unit is set at the reserved assembly gap. The capping segment unit is connected to the end face of the adjacent precast segment unit to achieve circumferential closure.

4. The precast segment unit based on prestressed cable threading according to claim 1, characterized in that, It includes an arc-shaped segment body, which is integrally precast from ultra-high performance concrete, and the segment body has a wall-attached side and an opposing cavity side; At least one cable groove is provided circumferentially on the wall-attached side. The cable groove extends from the bottom end to the top end of the segment body. Cable through holes are provided at both ends of the cable groove, and the cable through holes are respectively provided on the top and bottom end faces of the segment body. The segment body is provided with grouting holes that communicate with the cable groove; several transverse connecting bolt holes are provided on the side of the cavity; tenons or mortises are provided at the top, bottom and side ends of the segment body respectively.

5. The ultra-high performance concrete structure based on prestressed cable as described in claim 1, characterized in that, Several guide cable limiting platforms are arranged at intervals along the length of the cable groove; the guide cable limiting platforms are fixed to the bottom of the cable groove, and a semi-circular groove is provided at the upper end of the guide cable limiting platforms.

6. The ultra-high performance concrete structure based on prestressed cable as described in claim 5, characterized in that, The cable groove is provided in three sections, and each cable groove has two sets of guide cable limiting platforms. The cross-sectional shape of the cable groove is circular, U-shaped, trapezoidal, or rectangular; The precast segment unit has three pairs of transverse connecting bolt holes, which are symmetrically located at the upper, middle and lower parts of the segment body. Adjacent precast segment units along the extension direction of the tunnel are connected by arc bolts passing through the transverse connecting bolt holes.

7. The ultra-high performance concrete structure based on prestressed cable as described in claim 4, characterized in that, Continuous pressure grooves are provided at the top, bottom and both sides of the tube segment body, and water-stop strips or sealant are provided in the pressure grooves.

8. A construction method for ultra-high performance concrete structures based on prestressed cable threading, characterized in that, Includes the following steps: a) To construct and repair the foundation of newly excavated tunnels, or to clean, level and treat the interface of the inner foundation of existing tunnels. b) Assemble multiple precast tunnel segments sequentially along the circumference of the tunnel body, with the tenons and mortises on the top and bottom ends of adjacent precast tunnel segments fitting together to form a ring of precast tunnel segments arranged circumferentially. c) During the circumferential assembly process of step b), prestressed cables are simultaneously threaded through each cable groove, so that the prestressed cables pass through the cable holes of adjacent precast segment units in sequence, and form exposed sections outside the precast segment system. d) The exposed section of the prestressed cable is tensioned in stages using a tensioning device until the design prestress value is reached, and the cable head is anchored by an anchoring mechanism to put the prestressed cable in a prestressed tension state. e) Through the grouting holes on the precast segment unit, the back concrete filling layer is poured from bottom to top, and the back concrete filling layer is integrally bonded to the precast segment system, prestressed cable body and the tunnel wall. f) Cut off excess prestressed cables and remove the tensioning device.

9. The construction method for ultra-high performance concrete structures based on prestressed cable threading according to claim 8, characterized in that, After completing step d), the capping segment unit is installed at the circumferentially reserved assembly gap, so that the prefabricated segment system achieves circumferential closure.

10. The construction method for ultra-high performance concrete structures based on prestressed cable-stayed structures according to claim 8, characterized in that, A concrete invert or foundation is installed at the bottom of the tunnel body, and the lower end of the precast segment system and the anchoring mechanism are cast and fixed to the concrete invert or foundation.

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