Construction method of fault-crossing tunnel supporting structure
By using high-ductile concrete slabs and buckling support rods in the tunnel combined with magnesium phosphate concrete protective layer, the problems of brittle cracking and insufficient energy consumption capacity of traditional tunnel support structures when fault staggers are staggered, and a high-ductile and self-repaired tunnel support structure is achieved, which improves the seismic performance and durability of the tunnel.
Patent Information
- Application Number
- CN202510573350.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-06
- Publication Date
- 2025-07-25
AI Technical Summary
Traditional tunnel support structures are prone to structural cracking when faults are staggered, and the existing connection devices have unadjustable stiffness and single energy consumption capacity, resulting in insufficient safety in tunnels in high-intensity seismic areas and low repair efficiency.
The construction method of combining high-ductile concrete slabs with buckling support rods with magnesium phosphate concrete protective layer is adopted. By fixing precast concrete slabs between tunnel pipe sheets, setting up V-shaped grooves and hinges, installing buckling support rods, and pouring high-ductile concrete and magnesium phosphate concrete protective layer on them, forming distributed damage control and self-healing capabilities.
It significantly improves the deformation adaptability of the tunnel support structure under fault staggering, realizes distributed control and long-term durability of structural damage, can effectively absorb seismic energy, limit the deformation of tunnel pipe sheets, maintain structural integrity, and have self-healing characteristics.
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Abstract
Description
Technical Field
[0001] The present application relates to the technical field of tunnel cross-fault seismic technology, and particularly to a construction method for a cross-fault tunnel support structure. Background Art
[0002] In the field of tunnel engineering, the non-uniform large deformation caused by the movement of active faults is a major technical challenge for the seismic design of underground structures. The traditional cast-in-place concrete support structure is designed based on the small deformation assumption, and its brittle material characteristics lead to structural cracking when the fault movement exceeds ±50 mm. Moreover, the existing hinged joints mostly adopt discrete connection devices such as rubber bearings or steel springs, which have problems such as non-adjustable rotational stiffness and single energy dissipation capacity.
[0003] In recent years, although the shape memory alloy damper (SMA) adopted at home and abroad can achieve partial self-centering function, its high material cost (about 8-10 times that of conventional steel) severely restricts the engineering promotion. More prominently, the existing support system often suffers irreversible damage after experiencing fault movement, and the deep-buried tunnel environment leads to a narrow repair working surface, and the repair efficiency of the conventional grouting reinforcement method is less than 60% of the original structural performance.
[0004] The above technical bottlenecks severely restrict the whole-life cycle safety of traffic tunnels in high-intensity earthquake areas, and there is an urgent need to develop a new support system with large deformation adaptability, hierarchical energy dissipation mechanism and self-repair characteristics. Summary of the Invention
[0005] In view of this, the embodiments of the present application provide a construction method for a cross-fault tunnel support structure, which can significantly improve the deformation adaptability of the support structure under the action of fault movement. At the same time, relying on the strain hardening characteristics of high-ductility concrete and the micro-crack self-healing ability of the magnesium phosphate concrete protective layer, the distributed control of structural damage and the long-term durability guarantee are realized.
[0006] To achieve the above object, the present application adopts the following technical solutions:
[0007] The embodiments of the present application provide a construction method for a cross-fault tunnel support structure, including:
[0008] Fix a precast concrete slab between two tunnel segments. A V-shaped groove is opened at the upper end of the concrete slab. The length direction of the V-shaped groove is the same as the length direction of the gap between the two tunnel segments, and the opening of the V-shaped groove faces the outside of the tunnel segment;
[0009] Open a plurality of pairs of embedding grooves on both side walls of the V-shaped groove, and fixedly set a hinge joint in each embedding groove. Each pair of embedding grooves includes two embedding grooves oppositely arranged on both side walls of the V-shaped groove;
[0010] Hinge the two ends of the buckling support rod to two hinge joints fixed on opposite side walls of the V-shaped groove, each pair of hinge joints corresponding to one buckling support rod;
[0011] Using high ductility concrete to cast the V-shaped groove and fill the V-shaped groove;
[0012] After the high-ductility concrete is cooled and solidified, a magnesium phosphate concrete protective layer is poured on the high-ductility concrete.
[0013] In some embodiments, a steel plate is embedded inside the two side walls of the V-shaped groove, and a hinged part is provided on the steel plate. The hinged part is exposed after an embedding groove is opened on the two side walls of the V-shaped groove, and the hinged part is connected to the buckling support rod.
[0014] In some embodiments, the buckling brace comprises a steel sleeve, an inner concrete core, and an unbonded insulation material;
[0015] The inner core concrete core is arranged inside the steel sleeve, the non-bonded insulating material is arranged between the inner core concrete core and the steel sleeve, and both ends of the inner core concrete core are hinged to the steel sleeve with hinged joints, and the inner core concrete core is connected to the hinged part.
[0016] In some embodiments, the buckling support rod further comprises two joints;
[0017] The two joints are respectively located at the two ends of the buckling support rod, and are both fixedly connected to the steel sleeve and the inner core concrete core;
[0018] The two joints are connected to the hinged parts respectively.
[0019] In some embodiments, the non-bonded isolation unit is made of silicone.
[0020] In some embodiments, a plurality of anchor rods are further disposed inside the two side walls of the V-shaped groove, and the plurality of anchor rods fix the steel plate inside the two side walls of the V-shaped groove.
[0021] In some embodiments, a plurality of grouting holes with preset intervals are provided at the bottom of the V-shaped groove;
[0022] The method of casting the V-shaped groove with high ductility concrete comprises: injecting high ductility concrete into the V-shaped groove through a grouting hole, and vibrating the injected high ductility concrete with a high-frequency insertion vibrator.
[0023] In some embodiments, the prefabricated concrete slab is made of concrete mixed with steel fibers.
[0024] In some embodiments, the process of making the concrete mixed with steel fibers includes:
[0025] Put steel fibers, water and a dispersant into a fiber dispersing machine and stir for 5 to 10 minutes to evenly disperse the steel fibers in water to form a fiber slurry; wherein, the dosage of the dispersant is 0.1% to 0.3% of the mass of the steel fibers.
[0026] Add the fiber slurry to the mixture of cement, mineral admixture and aggregate that has been stirred well, and continue to stir for 3 to 5 minutes to evenly distribute the steel fibers in the concrete, obtaining the concrete with steel fibers added; wherein, the volume of the steel fibers is 2% to 3% of the volume of the concrete with steel fibers added.
[0027] In some embodiments, the thickness of the magnesium phosphate concrete protective layer is greater than or equal to 50 mm.
[0028] The beneficial effects of the embodiments of the present application compared with the prior art include:
[0029] When an earthquake occurs, seismic waves will be transmitted to the tunnel segment through the bedrock. Since the precast concrete slabs have high toughness, they can effectively absorb and disperse seismic energy, reducing the direct impact of seismic waves on the tunnel segment; and both ends of the buckling support rod are installed on the groove walls of the V-shaped groove, which can limit the lateral displacement of the tunnel segment during an earthquake, prevent excessive deformation of the tunnel structure, maintain the overall stability of the tunnel segment, and ensure the structural integrity of the tunnel segment during an earthquake.
[0030] The embodiments of the present application can significantly improve the deformation adaptability of the support structure under the action of fault dislocation. At the same time, relying on the strain hardening characteristics of high ductility concrete and the microcrack self-healing ability of the magnesium phosphate concrete protective layer, distributed control of structural damage and long-term durability guarantee are realized.
[0031] In addition, both ends of the buckling support rod are installed on the two side walls of the V-shaped groove by using a hinged connection form, which is easy to disassemble and replace the buckling support rod. Under the action of repeated loads such as earthquakes, the support structure of the cross-fault tunnel can withstand a large amount of cyclic deformation and is not prone to fatigue failure, and can play a shock absorption role for the cross-fault tunnel for a long time. BRIEF DESCRIPTION OF THE DRAWINGS
[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.
[0033] Figure 1 It is a schematic flow chart of the construction method of the cross-fault tunnel support structure provided by the embodiments of the present application;
[0034] Figure 2 Schematic diagram of the concrete slab with a V-shaped groove provided by an embodiment of the present application;
[0035] Figure 3 Schematic diagram of installing a buckling support rod in an embedding groove provided by an embodiment of the present application;
[0036] Figure 4 Schematic diagram of the connection between the buckling support rod and the steel plate hinge part provided by an embodiment of the present application;
[0037] Figure 5 Schematic diagram of the buckling support rod provided by an embodiment of the present application;
[0038] Figure 6 Schematic diagram after pouring high-ductility concrete into the V-shaped groove provided by an embodiment of the present application;
[0039] Figure 7 Schematic diagram after pouring a magnesium phosphate concrete protective layer provided by an embodiment of the present application. Specific embodiments
[0040] The following further clarifies the present application with reference to specific embodiments. The following embodiments will help those skilled in the art further understand the function of the present application, but do not limit the present application in any form. It should be noted that those of ordinary skill in the art can make several modifications and improvements without departing from the concept of the present application. These all fall within the protection scope of the present application.
[0041] To make the purpose, technical solution and advantages of the present application clearer, the following will be described through specific embodiments with reference to the accompanying drawings.
[0042] Refer to Figure 1 , the construction method of the cross-fault tunnel support structure provided by the embodiment of the present application may include steps 101 to 105, which are described in detail as follows:
[0043] Step 101, fix the precast concrete slab between two tunnel segments, and a V-shaped groove is opened at the upper end of the concrete slab.
[0044] Among them, the length direction of the V-shaped groove is consistent with the length direction of the gap between the two tunnel segments, and the opening of the V-shaped groove faces the outside of the tunnel segment.
[0045] In the embodiment of the present application, the width of the V-shaped groove gradually increases in the direction from the bottom of the groove to the opening of the groove.
[0046] The V-shaped groove with gradually increasing width can be used as a deformation joint or stress release area of the support structure of the cross-fault tunnel. When the support structure of the cross-fault tunnel is subjected to external stress, the V-shaped groove can provide a certain deformation space for the flexible shock-absorbing and self-resetting lining structure of the cross-fault tunnel, reduce the internal stress concentration of the flexible shock-absorbing and self-resetting lining structure of the cross-fault tunnel, and improve the structural stability.
[0047] The V-shaped groove (as Figure 2 shown) has good mechanical stability and can adapt to different load distributions.
[0048] In some embodiments, the above-mentioned precast concrete slab is a high-ductility concrete slab, and the material can be concrete mixed with steel fibers.
[0049] Specifically, the production process of the concrete mixed with steel fibers can include:
[0050] Put the steel fibers, water and dispersant into a fiber disperser and stir for 5 to 10 minutes to evenly disperse the steel fibers in the water to form a fiber slurry; wherein, the dosage of the dispersant is 0.1% to 0.3% of the mass of the steel fibers;
[0051] Add the fiber slurry to the mixture of cement, mineral admixture and aggregate that has been stirred well, and continue to stir for 3 to 5 minutes to evenly distribute the steel fibers in the concrete to obtain the concrete mixed with steel fibers; wherein, the volume of the steel fibers is 2% to 3% of the volume of the concrete mixed with steel fibers.
[0052] The above-mentioned concrete mixed with steel fibers can achieve material properties with a tensile strength ≥ 8 MPa and an ultimate elongation rate > 3%.
[0053] In the embodiments of the present application, the tunnel segment can be cylindrical or horseshoe-shaped. After the precast concrete slab is arranged between two adjacent tunnel segments, the shape formed by the precast concrete slab is also cylindrical or horseshoe-shaped. Correspondingly, the V-shaped grooves formed by connecting multiple precast concrete slabs are connected and enclose a cylindrical or horseshoe-shaped shape.
[0054] Step 102, open a plurality of pairs of embedding grooves on the two side walls of the V-shaped groove, and fixedly arrange a hinge joint in each embedding groove.
[0055] Wherein, each pair of embedding grooves includes two embedding grooves oppositely arranged on the two side walls of the V-shaped groove.
[0056] As Figure 3 shown, embedding grooves can be opened on the two side walls of the V-shaped groove, and the embedding grooves are opposite to each other in pairs to form a plurality of pairs of embedding grooves, and each pair of embedding grooves is used to place a buckling support rod.
[0057] Step 103: Hinge both ends of the buckling support rod to two hinge joints fixed on the opposite two side walls of the V-shaped groove.
[0058] Among them, each pair of hinge joints corresponds to a buckling support rod, as Figure 3 shown.
[0059] In some embodiments, as Figure 4 shown, steel plates (such as Q345B steel plates with a thickness of 30 mm) can be embedded inside the two side walls of the V-shaped groove. Hinge parts are provided on the steel plates. After embedding grooves are opened on the two side walls of the V-shaped groove, the hinge parts are exposed, and the hinge parts are connected to the buckling support rod.
[0060] Optionally, a plurality of anchor bolts can also be provided inside the two side walls of the V-shaped groove, and the plurality of anchor bolts fix the steel plates more firmly inside the two side walls of the V-shaped groove. The above-mentioned anchor bolts can be Φ32 high-strength anchor bolts with a tensile strength ≥ 900 Mpa.
[0061] In some embodiments, referring to Figure 5 , the buckling support rod can include a steel sleeve, a core concrete core, and a non-bonded isolation material. The core concrete core is arranged inside the steel sleeve, the non-bonded isolation material is arranged between the core concrete core and the steel sleeve, and the steel sleeve and the core concrete core are connected to the hinge part.
[0062] Optionally, the buckling support rod can also include two joints; the two joints are respectively located at both ends of the buckling support rod, and are both fixedly connected to the steel sleeve and the core concrete core; the two joints are respectively connected to the hinge part.
[0063] Under the action of external forces such as earthquakes, all the axial forces borne by the buckling support rod are borne by the core concrete core. When the axial force reaches a certain value, the core concrete core will enter the plastic deformation stage and yield. In the repeated tensile and compression cycles, the core concrete core absorbs and dissipates seismic energy through this plastic deformation.
[0064] The steel sleeve provides lateral restraint for the core concrete core to prevent the core concrete core from buckling as a whole or locally when compressed. Under the action of pressure, the core concrete core has a tendency to expand and bend outwards, and the steel sleeve can limit this deformation, so that the core concrete core can still maintain stable mechanical properties under greater pressure, thus ensuring that the buckling support rod can also function normally when compressed.
[0065] The unbonded isolation material is located between the inner core concrete core and the steel sleeve and is generally made of unbonded material. The function of the unbonded isolation material is to provide a sliding interface when the inner core concrete core is stressed and deformed, reduce the friction between the inner core concrete core and the steel sleeve, ensure that the inner core concrete core has similar mechanical properties as much as possible when in tension and compression, avoid a large increase in the axial pressure caused by the friction between the inner core concrete core and the steel sleeve after the inner core concrete core expands due to compression, enable the inner core concrete core to stretch and compress more smoothly, and ensure mechanical stability.
[0066] The above buckling bracing has a simple structure, an initial yield force of 500 kN, a limit bearing capacity of up to 1200 kN, a stiffness in the elastic stage of 15 kN / mm, and a stiffness in the plastic stage of 3 kN / mm. In the elastic stage, the buckling bracing can provide lateral stiffness for the cross-fault tunnel support structure, resist minor earthquakes and wind loads. In the elastoplastic stage, the buckling bracing has strong deformation ability and good hysteretic performance, and can effectively resist strong earthquakes. Compared with the traditional support structure without such a special energy dissipation mechanism, the embodiment of the present application can better cope with the dynamic load of earthquakes and reduce the damage to the cross-fault tunnel support structure caused by earthquakes.
[0067] Exemplarily, the material of the above unbonded isolation unit can be silica gel, and the silica gel material can effectively improve the seismic damping of the structure and absorb the dispersed stress brought by earthquakes.
[0068] In the embodiment of the present application, the two ends of the buckling bracing are installed on the two side walls of the V-shaped groove by an articulated connection form, which is easy to disassemble and replace the buckling bracing. Under the action of repeated loads such as earthquakes, the cross-fault tunnel support structure can withstand a large amount of cyclic deformation and is not prone to fatigue failure, and can play a role in seismic damping for the cross-fault tunnel for a long time.
[0069] Step 104, pour high-ductility concrete into the V-shaped groove to fill the V-shaped groove.
[0070] In some embodiments, as Figure 2 shown, a plurality of grouting holes with a preset interval can be opened at the bottom of the V-shaped groove. The implementation process of Step 104 can include: injecting high-ductility concrete into the V-shaped groove through the grouting holes, and vibrating the injected high-ductility concrete with a high-frequency inserted vibrator, as Figure 6 shown.
[0071] Exemplarily, a layered pouring operation can be performed, and a high-frequency inserted vibrator (frequency ≥ 12 kHz) can be used to ensure that the compactness of the poured high-ductility concrete is > 98%. The vibration in the arch crown area is particularly strengthened, and the high-ductility concrete is injected into the V-shaped notch through the grouting holes and vibrated.
[0072] Step 105: After the high-ductility concrete cools and solidifies, pour a magnesium phosphate concrete protective layer on the high-ductility concrete.
[0073] Exemplarily, the thickness of the magnesium phosphate concrete protective layer can be greater than or equal to 50 mm.
[0074] As Figure 7 shown, after the high-ductility concrete cools and solidifies, a 50-mm-thick magnesium phosphate concrete protective layer can be sprayed on the upper surface of the high-ductility concrete by a wet spraying process. Its unique hydrated product crystallization characteristics can achieve self-healing of microcracks below 0.3 mm, forming a permanent anti-seepage barrier.
[0075] Magnesium phosphate concrete has the characteristics of high strength and wear resistance compared with ordinary concrete, and can better protect the tunnel surface. Moreover, magnesium phosphate concrete has strong adhesion and good stability, and can prevent the concrete from falling off and breaking due to external forces or erosion. The concrete doped with steel fibers is a special high-performance concrete, which can improve the tear resistance of the second concrete support layer 20, improve the seismic resistance, and extend the service life.
[0076] When an earthquake occurs, seismic waves will be transmitted to the tunnel segments through the bedrock. Since the precast concrete segments have high toughness, they can effectively absorb and disperse seismic energy, reducing the direct impact of seismic waves on the tunnel segments. The two ends of the buckling support rod are installed on the groove walls of the V-shaped grooves, which can limit the lateral displacement of the tunnel segments during an earthquake, prevent the tunnel structure from deforming too much, maintain the overall stability of the tunnel segments, and ensure the structural integrity of the tunnel segments during an earthquake.
[0077] The above construction method of the cross-fault tunnel support structure has the following beneficial effects:
[0078] 1. Multi-scale material collaborative reinforcement: Through the cross-scale hybrid effect of steel fibers in the concrete segments (steel fibers bear the principal stress and polypropylene fibers inhibit the propagation of microcracks), the tear resistance performance of the cross-fault tunnel support structure is increased by 2.3 times (compared with ordinary C50 concrete); combined with the hierarchical energy dissipation characteristics of the buckling support rod (elastic stage stiffness 15 kN / mm, plastic stage stiffness 3 kN / mm), more than 60% of the seismic energy can be directionally dissipated.
[0079] 2. Three-level deformation coordination mechanism: Construct a collaborative working system of "precast high-ductility concrete segments - plastic energy dissipation of buckling support rods - stress release of deformation joints", so that the overall structure can adapt to a fault displacement of ±300 mm without structural damage, far exceeding the deformation limit of ±50 mm of the traditional support structure.
[0080] Through the systematic innovation of materials-structure-technology, this construction method provides an innovative construction method that can achieve the goals of deformation adaptability, energy consumption efficiency, and long-term durability for solving the technical problems of "vulnerable to strong earthquakes and difficult to repair" in active fault tunnels and tunnel engineering in high-intensity earthquake areas.
[0081] The above-described embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included within the protection scope of the present invention.
Claims
1. A construction method for a cross-fault tunnel support structure, characterized in that, include: A prefabricated concrete plate is fixed between two tunnel segments, wherein a V-shaped groove is provided on the upper end of the concrete plate, wherein the length direction of the V-shaped groove is consistent with the length direction of the gap between the two tunnel segments, and the opening of the V-shaped groove faces the outer side of the tunnel segment; A plurality of pairs of embedding grooves are provided on both side walls of the V-shaped groove, a hinge joint is fixedly arranged in each embedding groove, and each pair of embedding grooves includes two embedding grooves arranged oppositely on both side walls of the V-shaped groove; Hinge the two ends of the buckling support rod to two hinge joints fixed on opposite side walls of the V-shaped groove, each pair of hinge joints corresponding to one buckling support rod; Using high ductility concrete to cast the V-shaped groove and fill the V-shaped groove; After the high-ductility concrete is cooled and solidified, a magnesium phosphate concrete protective layer is poured on the high-ductility concrete.
2. The construction method of the cross-fault tunnel support structure according to claim 1, wherein, Steel plates are embedded inside the two side walls of the V-shaped groove, and hinged parts are arranged on the steel plates. The hinged parts are exposed after embedding grooves are opened on the two side walls of the V-shaped groove, and the hinged parts are connected to the buckling support rod.
3. The construction method of the cross-fault tunnel support structure according to claim 2, characterized in that, The buckling support rod comprises a steel sleeve, an inner core concrete core and an unbonded insulating material; The inner core concrete core is arranged inside the steel sleeve, the non-bonded insulating material is arranged between the inner core concrete core and the steel sleeve, and the steel sleeve and the inner core concrete core are connected to the hinged portion.
4. The construction method of the cross-fault tunnel support structure according to claim 3, characterized in that, The buckling support rod also includes two joints; The two joints are respectively located at two ends of the buckling support rod, and are both fixedly connected to the steel sleeve and the inner core concrete core; the two joints are respectively connected to the hinged parts.
5. The construction method of the cross-fault tunnel support structure according to claim 3, characterized in that, The material of the non-bonding isolation unit is silica gel.
6. The construction method of the cross-fault tunnel support structure according to claim 2, characterized in that, A plurality of anchor rods are also arranged inside the two side walls of the V-shaped groove, and the plurality of anchor rods fix the steel plate inside the two side walls of the V-shaped groove.
7. The construction method of the cross-fault tunnel support structure according to claim 1, characterized in that A plurality of grouting holes with preset intervals are provided at the bottom of the V-shaped groove; The method of casting the V-shaped groove with high ductility concrete comprises: injecting high ductility concrete into the V-shaped groove through a grouting hole, and vibrating the injected high ductility concrete with a high-frequency insertion vibrator.
8. The construction method of the cross-fault tunnel support structure according to claim 1, characterized in that, The material of the prefabricated concrete slab is concrete mixed with steel fibers.
9. The construction method of the cross-fault tunnel support structure according to claim 8, characterized in that, The manufacturing process of the concrete mixed with steel fiber includes: Put the steel fiber, water and dispersant into a fiber disperser and stir for 5 to 10 minutes to evenly disperse the steel fiber in the water to form a fiber slurry; wherein the amount of the dispersant is 0.1% to 0.3% of the mass of the steel fiber; The fiber slurry is added to the stirred mixture of cement, mineral admixture and aggregate, and the stirring is continued for 3 to 5 minutes to make the steel fibers evenly distributed in the concrete, thereby obtaining the concrete mixed with steel fibers; wherein the volume of the steel fibers is 2% to 3% of the volume of the concrete mixed with steel fibers.
10. The construction method of the cross-fault tunnel support structure according to claim 1, characterized in that The thickness of the magnesium phosphate concrete protective layer is greater than or equal to 50 mm.