A lining structure applicable to mountain tunnels and its construction method

Abstract

The present invention relates to the technical field of tunnels, and provides a lining structure applicable to mountain tunnels and a construction method thereof, including an arch wall lining assembly and an invert assembly. The arch wall lining assembly includes an arch wall corrugated steel plate layer and an arch wall secondary lining layer. The invert assembly includes an invert corrugated steel plate layer, an invert secondary lining layer, a frame column layer and a road surface layer. The bottom of the frame column layer is embedded in the invert secondary lining layer, the road surface layer is laid on the top of the frame column layer, and the end of the invert corrugated steel plate layer is connected to the end of the arch wall corrugated steel plate layer. The present application provides a novel lining structure. In particular, by setting the traditional invert backfill layer into a frame layer structure, the amount of concrete used can be significantly reduced, while ensuring the safety and stability of the tunnel, the material cost and construction cost are also reduced, and the economic benefit is improved. In addition, the present application also provides a construction method and a design method for the frame column layer, which has direct guiding significance for actual projects.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnels, and in particular to a lining structure applicable to mountain tunnels and a construction method thereof. Background Art

[0002] At present, the lining structure of mountain tunnels generally adopts a composite lining structure, that is, an initial support + secondary lining structure form. Among them, the lining structure includes an arch wall lining structure and an invert lining structure. The arch wall lining structure mainly includes an arch wall initial support and an arch wall secondary lining. The arch wall initial support is a support structure constructed immediately after the tunnel excavation, mainly including anchor bolts, steel meshes, and shotcrete, which are used to quickly seal the excavation surface and prevent the surrounding rock from loosening and collapsing. The main function of the arch wall secondary lining is to further enhance the safety and stability of the tunnel.

[0003] The tunnel invert structure mainly includes an invert initial support, an invert secondary lining, a backfill layer, and a pavement layer. Among them, the invert initial support is a support structure constructed immediately after the tunnel excavation, mainly including anchor bolts, steel meshes, and shotcrete, which are used to quickly seal the excavation surface and prevent the surrounding rock from loosening and collapsing. The main function of the invert secondary lining is to further enhance the safety and stability of the tunnel. The backfill layer is located between the secondary lining and the pavement layer. The main function of the backfill layer is to fill the voids generated during the tunnel excavation, reduce the ground settlement, and play a role in water isolation at the same time. The pavement layer directly bears the vehicle load and the pressure of pedestrians walking. The pavement layer is usually paved with materials such as asphalt concrete or cement concrete.

[0004] The lining structure in the prior art has problems of complex construction, long construction period, and high concrete consumption. In particular, the tunnel invert backfill layer is usually filled with C15 concrete, and the quantity per meter is large, which can reach 8 - 10 m³ / meter. Then, the reinforced concrete pavement base is cast in place, and finally the asphalt layer is laid. This not only consumes a large amount of concrete, but also has a long construction period.

[0005] In view of this, it is necessary to propose a lining structure applicable to mountain tunnels and a construction method thereof to solve or at least alleviate the above defects. Summary of the Invention

[0006] The main purpose of the present invention is to provide a lining structure applicable to mountain tunnels and a construction method thereof, so as to solve the technical problems of large construction material consumption and long construction period existing in the lining structure in the prior art.

[0007] To achieve the above object, the present invention provides a lining structure applicable to mountain tunnels, which includes an arch-wall lining assembly and an invert assembly. The arch-wall lining assembly and the invert assembly enclose to form an annular structure. Among them, the arch-wall lining assembly includes an arch-wall corrugated steel plate layer and an arch-wall secondary lining layer arranged successively from outside to inside along the radial direction of the tunnel. Among them, the arch-wall corrugated steel plate layer is provided with a first grouting hole and a first bolt hole for a first system bolt to penetrate through. Foamed concrete is injected into the interlayer space between the arch-wall corrugated steel plate layer and the surrounding rock through the first grouting hole to form a first foamed concrete layer.

[0008] The invert assembly includes an invert corrugated steel plate layer, an invert secondary lining layer, a frame column layer and a road surface layer arranged successively from bottom to top. Among them,

[0009] The invert corrugated steel plate layer is provided with a second grouting hole and a second bolt hole for a second system bolt to penetrate through. Foamed concrete is injected into the interlayer space between the invert corrugated steel plate layer and the surrounding rock through the second grouting hole to form a second foamed concrete layer. The bottom of the frame column layer is embedded in the invert secondary lining layer. The road surface layer is laid on the top of the frame column layer. The ends of the invert corrugated steel plate layer and the ends of the arch-wall corrugated steel plate layer are connected.

[0010] Preferably, the frame column layer includes a cover plate and a plurality of spaced column units. The lower end of each column unit is embedded in the invert secondary lining layer. The cover plate and the column units are integrally cast, and the cover plate is arranged on the top of the column units.

[0011] Preferably, the arch-wall corrugated steel plate layer includes a first corrugated steel plate body and two first connection components respectively connected to the ends of the first corrugated steel plate body. Each first connection component includes a first connection plate and a second connection plate. The first connection plate is connected to the bottom of the first corrugated steel plate body. The second connection plate is connected to the side of the first connection plate close to the invert corrugated steel plate layer. The second connection plate and the first connection plate form an L-shaped structure.

[0012] The invert corrugated steel plate layer includes a second corrugated steel plate body and two second connection components respectively connected to the ends of the second corrugated steel plate body. Each second connection component includes a third connection plate, a fourth connection plate and a fifth connection plate arranged in parallel and spaced apart. The fourth connection plate is connected to the end of the second corrugated steel plate body. The third connection plate is connected between the fourth connection plate and the fifth connection plate. The third connection plate, the fourth connection plate and the fifth connection plate enclose to form a U-shaped structure with the opening facing downwards.

[0013] Among them, the second connection plate is connected in the inner cavity of the U-shaped structure.

[0014] Preferably, a first connection hole for a bolt to pass through is formed in the fourth connecting plate, a second connection hole corresponding to the first connection hole is formed in the fifth connecting plate, a third connection hole corresponding to the first connection hole is formed in the second connecting plate, a first water stop strip is arranged between the second connecting plate and the fourth connecting plate, and a second water stop strip is arranged between the second connecting plate and the fifth connecting plate. The second connecting plate is connected to the inner cavity of the U-shaped structure by bolts passing through the first connection hole, the second connection hole and the third connection hole. Both the first water stop strip and the second water stop strip are arranged on the side of the bolt close to the third connecting plate.

[0015] Preferably, it further includes a vertical drain pipe assembly and a central longitudinal drainage ditch; wherein, the central longitudinal drainage ditch is arranged at the bottom center of the second corrugated steel plate body and is used for collecting the surrounding rock seepage water drained from the outer wall of the second corrugated steel plate body. The vertical drain pipe assembly includes a plurality of vertical drain pipes arranged at intervals along the extension direction of the central longitudinal drainage ditch. Each vertical drain pipe sequentially penetrates the second corrugated steel plate body and the inverted arch secondary lining layer from bottom to top and enters the interval space of the column unit. The bottom of the vertical drain pipe is communicated with the central longitudinal drainage ditch.

[0016] Preferably, the second connecting plate is provided with a water discharge hole facing the second corrugated steel plate body at a position below the fourth connecting plate.

[0017] The present invention also provides a construction method for a lining structure applicable to mountain tunnels, which is applied to the lining structure as described above and includes the following steps:

[0018] S1. After excavating the tunnel chamber, assemble the arch wall corrugated steel plate layer, inject foamed concrete through the first grouting hole on the back of the arch wall corrugated steel plate layer to form a first foamed concrete layer, and then drive the first system anchor bolts through the first anchor bolt holes.

[0019] S2. After excavating the inverted arch, first excavate the central longitudinal drainage ditch at the center of the arch bottom, fill an air bag in the central longitudinal drainage ditch, then assemble the inverted arch corrugated steel plate layer, and then connect the ends of the inverted arch corrugated steel plate layer and the ends of the arch wall corrugated steel plate layer.

[0020] S3. Inject foamed concrete through the second grouting hole at the bottom of the inverted arch corrugated steel plate layer to form a second foamed concrete layer, and then drive the second system anchor bolts through the second anchor bolt holes. After the foamed concrete solidifies, pierce the air bag through the vertical drain pipe.

[0021] S4. Pour the secondary lining layer of the inverted arch, and reserve assembly holes on the top surface of the secondary lining layer of the inverted arch according to the design requirements. After the secondary lining layer of the inverted arch solidifies, construct the frame column layer. Among them, insert the column units into the corresponding assembly holes, assemble the cover plates on the tops of the column units. After all the column units and cover plates are assembled, insert the first steel reinforcement cage into the column units, lay a single-layer steel mesh on the cover plates, and finally pour the cover plates and column units integrally. Among them, the cover plates are reserved with pouring holes corresponding to the column units.

[0022] S5. After the concrete of the cover plates solidifies, pour the secondary lining layer of the arch wall, and then lay the road surface layer on the tops of the cover plates.

[0023] Preferably, the frame column layer in the step S4 is obtained through the following design steps:

[0024] S41. Obtain the design value of the axial pressure of the frame column layer ;

[0025] S42. Determine the cross-sectional area of the column unit according to the design value of the axial pressure ; ;

[0026] S43. Determine the cross-sectional area of the longitudinal main reinforcement of the column unit according to the formula ; Among them, ; is the longitudinal main reinforcement ratio of the column unit;

[0027] S44. Determine the allowable stress value of the longitudinal tension ordinary reinforcement of the cover plate according to the formula ; Among them, ; is the member force characteristic coefficient of the cover plate; is the uneven coefficient of the longitudinal main reinforcement strain between cracks, is the elastic modulus of the steel bars of the cover plate, is the distance from the outer edge of the outermost longitudinal main reinforcement to the bottom edge of the tension zone, is the equivalent diameter of the longitudinal main reinforcement, is the longitudinal main reinforcement ratio calculated according to the effective tension concrete cross-sectional area; when is satisfied, take ; is the maximum crack width limit value of the cover plate;

[0028] S45. Determine the maximum mid-span bending moment value of the cover plate according to the formula ; , is the effective height of the cross-section of the cover plate;

[0029] S46. According to the formula Back-calculate the maximum span of the cover plate under the action of vehicle loads ; where is the equivalent uniform vehicle load, is the concentrated vehicle load;

[0030] S47, calculate the distance from the resultant force point of the longitudinal main reinforcement to the tension edge of the section according to the formula ; and determine the relative compression zone height of the cover plate according to the formula ; where is the design value of the axial compressive strength of concrete, is the coefficient of the equivalent rectangular stress diagram of the concrete compression zone, and b is taken as the span per meter of the cover plate;

[0031] S48, determine the minimum reinforcement area and of the cover plate that meets the requirements according to the formula , and then determine the reinforcement method of the cover plate according to the minimum reinforcement area ; where is the design value of the tensile strength of the reinforcement, is the minimum reinforcement ratio of the cover plate.

[0032] Preferably, the step S41 specifically includes the following steps:

[0033] Obtain the design value of the axial pressure of the frame column layer according to the formula ; where is the self-weight of the road surface layer, is the self-weight of the frame column layer, is the larger value between the self-weight load of the construction machinery during construction and the vehicle load during operation.

[0034] Preferably, the step S42 specifically includes the following steps:

[0035] Determine the cross-sectional area of the column unit according to the formula , unit: , where is the axial compression ratio limit, and d is the outer diameter of the column unit.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] The present invention provides a lining structure applicable to mountain tunnels and a construction method thereof, which includes an arch-wall lining assembly and an invert assembly. The arch-wall lining assembly includes an arch-wall corrugated steel plate layer and an arch-wall secondary lining layer. The invert assembly includes an invert corrugated steel plate layer, an invert secondary lining layer, a frame column layer, and a road surface layer. The bottom of the frame column layer is embedded in the invert secondary lining layer, the road surface layer is laid on the top of the frame column layer, and the ends of the invert corrugated steel plate layer are connected to the ends of the arch-wall corrugated steel plate layer.

[0038] This application provides a lining structure, especially using corrugated steel plates as the initial support and setting the traditional invert backfill layer into a frame layer structure, which can significantly reduce the amount of concrete used. While ensuring the safety and stability of the tunnel, it also reduces material costs and construction costs, improving economic benefits. In addition, this application also provides a construction method and a design method for the frame column layer, avoiding construction errors, improving construction efficiency while ensuring the structural safety and durability, avoiding blind selection in the actual process, reducing project waste, and ultimately promoting technology standardization and popularization. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0040] Figure 1 It is a schematic diagram of the application scenario of the overall structure in an embodiment of the present invention;

[0041] Figure 2 It is a schematic diagram of the invert drainage in an embodiment of the present invention;

[0042] Figure 3 It is a schematic diagram of the connection between the ends of the invert corrugated steel plate layer and the ends of the arch-wall corrugated steel plate layer in an embodiment of the present invention;

[0043] Figure 4 It is a side view of the arch-wall corrugated steel plate layer in an embodiment of the present invention;

[0044] Figure 5 It is a schematic diagram of the structure of the frame column layer in an embodiment of the present invention;

[0045] Figure 6 It is a plan view of the PVC board in an embodiment of the present invention;

[0046] Figure 7 It is a schematic diagram of the structure of the column unit in an embodiment of the present invention;

[0047] Figure 8 Schematic cross-sectional view of the PVC board in an embodiment of the present invention;

[0048] Figure 9 Schematic flow chart of the construction method in an embodiment of the present invention.

[0049] The implementation, functional features and advantages of the present invention will be further described in conjunction with the embodiments and with reference to the accompanying drawings.

[0050] Explanation of the reference numerals in the drawings:

[0051] 10. Arch wall lining assembly; 110. Arch wall corrugated steel plate layer; 111. First corrugated steel plate main body; 112. First connecting plate; 113. Second connecting plate; 114. Drainage hole; 120. Arch wall secondary lining layer; 20. Inverted arch assembly; 210. Inverted arch corrugated steel plate layer; 211. Second corrugated steel plate main body; 212. Third connecting plate; 213. Fourth connecting plate; 214. Fifth connecting plate; 215. Bolt; 220. First water stop strip; 230. Second water stop strip; 240. Inverted arch secondary lining layer; 250. Frame column layer; 251. Cover plate; 2511. PVC board; 2512. Annular docking groove; 2513. Pouring hole; 252. Column unit; 2521. PVC vertical pipe; 2522. Longitudinal main reinforcement; 260. Road surface layer; 30. Vertical drainage pipe assembly; 40. Central longitudinal drainage ditch. Detailed implementation manners

[0052] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0053] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0054] It should be noted that all the directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the drawings). If the specific posture changes, the directional indications will also change accordingly.

[0055] In addition, the descriptions involving "right part", "middle part", etc. in the present invention are for descriptive purposes only, and should not be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "right part" and "middle part" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between various embodiments may be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement it. 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 invention.

[0056] Please refer to the attached Figures 1 to 8 , a lining structure applicable to mountain tunnels provided in an embodiment of the present invention includes an arch wall lining assembly 10 and an invert assembly 20. The arch wall lining assembly 10 and the invert assembly 20 enclose to form an annular structure. Among them, the arch wall lining assembly 10 includes an arch wall corrugated steel plate layer 110 and an arch wall secondary lining layer 120 arranged in sequence from outside to inside along the tunnel radial direction. Among them, the arch wall corrugated steel plate layer 110 is provided with a first grouting hole (not shown in the figure) and a first anchor rod hole (not shown in the figure) for the first system anchor rod to penetrate. Foamed concrete is injected into the interlayer space between the arch wall corrugated steel plate layer 110 and the surrounding rock through the first grouting hole to form a first foamed concrete layer (not shown in the figure).

[0057] The invert assembly 20 includes an invert corrugated steel plate layer 210, an invert secondary lining layer 240, a frame column layer 250, and a road surface layer 260 arranged in sequence from bottom to top. Among them,

[0058] the invert corrugated steel plate layer 210 is provided with a second grouting hole (not shown in the figure) and a second anchor rod hole (not shown in the figure) for the second system anchor rod to penetrate. Foamed concrete is injected into the interlayer space between the invert corrugated steel plate layer 210 and the surrounding rock through the second grouting hole to form a second foamed concrete layer (not shown in the figure). The bottom of the frame column layer 250 is embedded in the invert secondary lining layer 240. The road surface layer 260 is laid on the top of the frame column layer 250. The end of the invert corrugated steel plate layer 210 is connected to the end of the arch wall corrugated steel plate layer 110.

[0059] Specifically, the corrugated steel plate layer 110 of the arch wall serves as the outer initial support structure, providing preliminary support and protection. By injecting foamed concrete through the first grouting holes, the interlayer space between the corrugated steel plate layer 110 of the arch wall and the surrounding rock is filled, which can effectively release the pressure of the surrounding rock and increase the stability and bearing capacity of the overall structure. In addition, since the corrugated steel plate itself is impermeable, it can achieve a good waterproof effect. On the other hand, the water-permeable characteristic of the foamed concrete can be utilized to provide a drainage channel, enabling groundwater to seep along the foamed concrete on the outer surface of the corrugated steel plate layer 110 of the arch wall to below the arch feet, and the groundwater can drain out through the original underground drainage channel via the fissures in the surrounding rock. The secondary lining layer 120 of the arch wall serves as the inner layer structure, providing further support and protection to ensure the stability and durability of the tunnel, and it can be obtained by shotcreting construction or cast-in-place construction.

[0060] The corrugated steel plate layer 210 of the inverted arch serves as the outer initial support structure of the inverted arch, providing preliminary support. By injecting foamed concrete through the second grouting holes, the interlayer space between the corrugated steel plate layer 210 of the inverted arch and the surrounding rock is filled, which can effectively release the pressure of the surrounding rock and increase the stability and bearing capacity of the overall structure. In addition, since the corrugated steel plate itself is impermeable, it can achieve a good waterproof effect. On the other hand, the water-permeable characteristic of the foamed concrete can be utilized to provide a drainage channel, enabling groundwater to seep along the foamed concrete on the outer surface of the corrugated steel plate layer 210 of the inverted arch to below the arch bottom, and the groundwater can drain out through the original underground drainage channel via the fissures in the surrounding rock.

[0061] The secondary lining layer 240 of the inverted arch serves as the inner layer structure of the inverted arch, providing further support and protection. The frame column layer 250 is embedded in the secondary lining layer 240 of the inverted arch, and its top supports the road surface layer 260, forming the longitudinal support structure of the tunnel.

[0062] Through the combined action of the corrugated steel plate layer, the foamed concrete layer, the system anchor bolts, and the secondary lining layer, the stability and bearing capacity of the inverted arch structure of the tunnel are enhanced in this application; the combined use of the corrugated steel plate layer and the secondary lining layer, as well as the filling of the foamed concrete, improves the waterproof performance and durability of the structure; the prefabrication and on-site construction of the corrugated steel plate layer and the frame column layer 250, as well as the grouting construction of the foamed concrete, shorten the construction period and reduce the amount of engineering materials; the construction process is greatly simplified and the construction period is shortened. In addition, in this application, the traditional inverted arch backfill layer is set as a frame layer structure, which can significantly reduce the amount of concrete used, and while ensuring the safety and stability of the tunnel, it also reduces the material cost and construction cost, improving the economic benefits.

[0063] Preferably, the road surface layer 260 includes precast road slabs and an asphalt layer. The precast road slabs are laid on top of the cover plate 251, and the asphalt layer is laid on top of the precast road slabs. The precast road slabs are produced in a factory, enabling standardized and large-scale production, greatly improving production efficiency. The precast road slabs can be quickly laid, reducing on-site construction time and labor costs. The asphalt layer, as the surface layer, can be laid after the precast road slabs are completed, further shortening the construction period.

[0064] Preferably, the thickness of the precast road slabs is set between 15 cm and 25 cm, and the thickness of the asphalt layer is set between 8 cm and 10 cm.

[0065] As a preferred embodiment, the frame column layer 250 includes a cover plate 251 and a plurality of spaced-apart column units 252. The lower end of each column unit 252 is embedded in the inverted arch secondary lining layer 240. The cover plate 251 and the column units 252 are integrally cast, and the cover plate 251 is provided on top of the column units 252.

[0066] Specifically, the frame column layer 250 is integrally cast by a plurality of column units 252 and a cover plate 251 to form a strong support system, which not only enhances the longitudinal support capacity of the tunnel inverted arch but also helps to resist the loads from the tunnel sidewalls and the top, improving the stability of the entire tunnel structure. At the same time, the frame column layer 250 adopts a form with a plurality of column units 252 arranged at intervals, which can change the existing form of the inverted arch backfill layer into a frame structure. While ensuring the safety and stability of the tunnel, it greatly reduces the amount of concrete used, thereby reducing material costs and construction costs and improving economic efficiency.

[0067] Preferably, the plurality of column units 252 are arranged in a rectangular array, and the spacing distance between adjacent two column units 252 is set to 100×100 cm. By setting the spacing distance between adjacent two column units 252 to 100 cm×100 cm, it can ensure that the load is more evenly distributed among the frame column layer 250, helping to reduce the risk of structural damage caused by load concentration and improving the bearing capacity of the tunnel. It can be understood that in other embodiments, those skilled in the art can also set the spacing distance between the column units 252 to other values according to actual needs.

[0068] Preferably, each of the column units 252 includes a PVC vertical pipe 2521 and a first steel reinforcement cage (not shown in the figure), the cover plate 251 includes a PVC plate 2511 and a single-layer steel mesh (not shown in the figure), the first steel reinforcement cage is disposed inside the PVC vertical pipe 2521, the single-layer steel mesh is disposed inside the PVC plate 2511, an annular docking groove 2512 matching the PVC vertical pipe 2521 is formed at the bottom of the PVC plate 2511, the PVC plate 2511 is docked on the top of the PVC vertical pipe 2521 through the annular docking groove 2512, a pouring hole 2513 corresponding to the PVC vertical pipe 2521 is reserved at the top of the PVC plate 2511, the longitudinal main reinforcement 2522 of the first steel reinforcement cage extends upward to be connected to the single-layer steel mesh, and concrete is poured through the pouring hole 2513 so that the cavity formed by enclosing the PVC vertical pipe 2521 and the PVC plate 2511 is filled with concrete.

[0069] Specifically, the first steel reinforcement cage, as the main load-bearing part of the column unit 252, provides high strength and stiffness. The longitudinal main reinforcement 2522 is connected to the single-layer steel mesh to form a continuous steel reinforcement framework, further enhancing the integrity and cooperative working ability between the column unit 252 and the cover plate 251, thereby improving the load-bearing capacity of the frame column layer 250; it is worth noting that the PVC vertical pipe 2521, as the outer layer of the column unit 252, has certain anti-corrosion, waterproof and durability properties, can protect the internal reinforced concrete structure from the erosion of the external environment, extend the service life of the column unit 252, and can also be used as a formwork for concrete pouring in the PVC vertical pipe 2521 to achieve the combined use of permanent and temporary structures. Similarly, the PVC plate 2511 can also be used as a formwork for upper pouring. Construction workers can first construct the PVC vertical pipe 2521, the first steel reinforcement cage, the PVC plate 2511, and the single-layer steel mesh, and then perform on-site concrete casting to achieve integral casting, improving construction efficiency and quality.

[0070] As a preferred embodiment, the arch wall corrugated steel plate layer 110 includes a first corrugated steel plate body 111 and two first connection components (not shown in the figure) respectively connected to the ends of the first corrugated steel plate body 111. Each of the first connection components includes a first connection plate 112 and a second connection plate 113. The first connection plate 112 is connected to the bottom of the first corrugated steel plate body 111, and the second connection plate 113 is connected to the side of the first connection plate 112 close to the inverted arch corrugated steel plate layer 210. The second connection plate 113 and the first connection plate 112 form an L-shaped structure.

[0071] The inverted arch corrugated steel plate layer 210 includes a second corrugated steel plate main body 211 and two second connection components respectively connected to the ends of the second corrugated steel plate main body 211. Each second connection component includes a third connection plate 212, a fourth connection plate 213 and a fifth connection plate 214 arranged in parallel at intervals. The fourth connection plate 213 is connected to the end of the second corrugated steel plate main body 211. The third connection plate 212 is connected between the fourth connection plate 213 and the fifth connection plate 214. The third connection plate 212, the fourth connection plate 213 and the fifth connection plate 214 enclose a U-shaped structure with the opening facing downwards. Among them, the second connection plate 113 is connected in the inner cavity of the U-shaped structure.

[0072] Further, the fourth connection plate 213 is provided with a first connection hole for a bolt 215 to pass through, the fifth connection plate 214 is provided with a second connection hole corresponding to the first connection hole, the second connection plate 113 is provided with a third connection hole corresponding to the first connection hole. A first water stop strip 220 is provided between the second connection plate 113 and the fourth connection plate 213, and a second water stop strip 230 is provided between the second connection plate 113 and the fifth connection plate 214. The second connection plate 113 is connected in the inner cavity of the U-shaped structure by the bolt 215 passing through the first connection hole, the second connection hole and the third connection hole. Both the first water stop strip 220 and the second water stop strip 230 are arranged on the side of the bolt 215 close to the third connection plate 212.

[0073] It should be noted that in this application, both the initial support of the inverted arch and the arch wall adopt corrugated steel plates. The connection between the inverted arch corrugated steel plate layer 210 and the arch wall corrugated steel plate layer 110 needs to take into account both construction convenience and structural waterproofing. As Figure 3 shown, an L-shaped first connection component is provided at the arch foot of the first corrugated steel plate main body 111, and a second connection component corresponding to the first connection component is provided at the end of the second corrugated steel plate main body 211. The second connection component is in a U-shaped structure, so it can be buckled on the L-shaped first connection component, and the outer side of the U-shaped second connection component is closely attached to the first connection component, that is, the fifth connection plate 214 is closely attached to the outer wall surface of the first corrugated steel plate main body 111, which is beneficial to conducting the horizontal force. Then, it is connected by bolts 215. Further, a first water stop strip 220 and the second water stop strip 230 are arranged in the inner cavity of the U-shaped structure, respectively on both sides of the second connection plate 113. After the bolts 215 are tightened, the first water stop strip 220 and the second water stop strip 230 can be extruded to form two waterproof layers, thus achieving both construction convenience and structural waterproofing.

[0074] As another preferred embodiment, it further includes a vertical drain pipe assembly 30 and a central longitudinal drainage ditch 40; wherein, the central longitudinal drainage ditch 40 is arranged at the bottom center of the second corrugated steel plate main body 211 for collecting the surrounding rock seepage water drained from the outer wall of the second corrugated steel plate main body 211. The vertical drain pipe assembly 30 includes a plurality of vertical drain pipes arranged at intervals along the extension direction of the central longitudinal drainage ditch 40. Each vertical drain pipe sequentially penetrates through the second corrugated steel plate main body 211 and the inverted arch secondary lining layer 240 from bottom to top and enters the spaced space of the column unit 252. The bottom of the vertical drain pipe is communicated with the central longitudinal drainage ditch 40.

[0075] It should be noted that the waterproof and drainage design of mountain tunnels in the prior art has always followed the following scheme: a waterproof layer is laid between the primary support and the secondary lining, longitudinal drain pipes are arranged at the arch feet on both sides, the longitudinal drain pipes are wrapped by the waterproof layer in an inverted manner, the groundwater is introduced into the longitudinal drain pipes, and then discharged from the tunnel through the transverse drain pipes into the longitudinal drainage ditch in the tunnel.

[0076] It is worth noting that this scheme changes the original drainage channel, which may cause changes in the regional surface water system, drying up the original ponds and streams, thereby affecting the local ecological environment and even the domestic water use of local residents.

[0077] Secondly, the waterproof materials and construction techniques greatly affect the waterproof and drainage effect. (1) Traditional waterproof materials and techniques are difficult to meet the special environmental requirements of tunnels and are prone to problems such as aging and damage, resulting in tunnel leakage. For example, in some tunnels in underwater or high-humidity environments, materials such as waterproof boards and waterstops are affected by long-term water erosion and structural deformation, shortening their service life. (2) When laying the waterproof board, if the surface of the primary support is uneven and there are sharp objects, it is easy to pierce the waterproof board; there may also be problems such as missed welding and false welding during the welding process, affecting the waterproof effect.

[0078] Finally, this scheme in the prior art is prone to blockage and inconvenient to maintain. (1) The circumferential, longitudinal, and transverse drain pipes in the tunnel drainage system may be blocked by sediment, debris, concrete residues, etc. during use. Especially the drain pipes behind the lining, once blocked, are difficult to repair and dredge. (2) When designing the drainage system, there may be deviations in the prediction of the tunnel water inflow. When encountering special situations such as heavy rain and extremely rich groundwater, or when the geological conditions change after the tunnel has been in operation for many years, the original designed drainage system may not be able to meet the drainage requirements, resulting in water accumulation in the tunnel. (3) In the waterproof and drainage system of existing drill-and-blast tunnels, the maintenance space for facilities such as drainage pipes behind the lining is small, the operation difficulty is large, and the maintenance cost is high. A large amount of manpower and material resources are required for inspection and repair, and even partial removal of the lining may be required for maintenance.

[0079] In view of the above problems, in the embodiments of the present application, a corrugated steel plate layer is used as the primary support, and the tunnel is wrapped inside the corrugated steel plate layer. Since the corrugated steel plate layer itself is impervious to water, it can play a good waterproofing role. A second foamed concrete layer is backfilled outside the corrugated steel plate layer. On the one hand, it can serve as a buffer layer, and on the other hand, it can utilize the water-permeable characteristic of the foamed concrete to provide a drainage channel, so that the groundwater seeps along the foamed concrete on the outer surface of the invert corrugated steel plate layer 210 to the central longitudinal drainage ditch 40 at the bottom of the arch. Part of the groundwater can pass through the surrounding rock fissures and be discharged from the original underground drainage channel, and the excess groundwater can be discharged out of the tunnel through the central longitudinal drainage ditch 40 at the bottom of the arch.

[0080] Specifically, during the heavy rain season when the groundwater level surges sharply and the central longitudinal drainage ditch 40 at the bottom of the arch cannot meet the drainage requirements, the excess groundwater can be introduced into the tunnel through the vertical drain pipe assembly 30, and the interval space of the column unit 252 is fully utilized to discharge the groundwater from the tunnel to the outside of the tunnel. In this way, on the one hand, the groundwater resources can be protected and the original drainage channel can be restored, and on the other hand, when the groundwater level surges sharply, the safety of the tunnel structure can be protected. This embodiment completely changes the tunnel waterproof and drainage design, reduces the impact on groundwater, and helps to protect the ecological environment. Secondly, various drain pipes in the tunnel are cancelled, solving the hidden danger of drainage blockage caused by the failure of the drain pipes, and the maintenance is simple.

[0081] Preferably, the diameter of the vertical drain pipe is set between 200 mm and 300 mm, and the width of the central longitudinal drainage ditch 40 is set between 50 cm and 80 cm.

[0082] Furthermore, the second connecting plate 113 is provided with a water discharge hole 114 facing the second corrugated steel plate main body 211 at a position below the fourth connecting plate 213. The main function of the water discharge hole 114 opened on the second connecting plate 113 is to achieve drainage. When water accumulates in the area between the second corrugated steel plate main body 211 and the fourth connecting plate 213, this water can flow out through the water discharge hole 114, thus avoiding the accumulation of water in this area. This is beneficial for preventing corrosion, keeping the structure dry, and improving the durability of the overall structure.

[0083] Please refer to the atta Figure 9 chment. The present invention also provides a construction method for a lining structure applicable to mountain tunnels, which is applied to the lining structure as described above, and includes the following steps:

[0084] S1, after excavating the tunnel chamber, assemble the arch wall corrugated steel plate layer 110, inject foamed concrete through the first grouting hole on the back of the arch wall corrugated steel plate layer 110 to form the first foamed concrete layer, and then drive the first system anchor through the first anchor hole;

[0085] S2. After excavating the inverted arch, first excavate the central longitudinal drainage ditch 40 at the center of the arch bottom, fill the airbag in the central longitudinal drainage ditch 40, then assemble the corrugated steel plate layer 210 of the inverted arch, and then connect the ends of the corrugated steel plate layer 210 of the inverted arch and the ends of the corrugated steel plate layer 110 of the arch wall;

[0086] The specific steps are as follows: Invert the U-shaped second connection component onto the L-shaped first connection component. Through extrusion, by judging whether the bolt 215 reaches the preset position, when it reaches the preset position, then fix it through the bolt 215, so as to realize the sealed connection between the end of the corrugated steel plate layer 210 of the inverted arch and the end of the corrugated steel plate layer 110 of the arch wall;

[0087] S3. Inject foamed concrete through the second grouting hole at the bottom of the corrugated steel plate layer 210 of the inverted arch to form the second foamed concrete layer, then drive the second system anchor through the second anchor hole. After the foamed concrete solidifies, pierce the airbag through the vertical drain pipe;

[0088] S4. Pour the secondary lining layer 240 of the inverted arch, and reserve assembly holes on the top surface of the secondary lining layer 240 of the inverted arch according to the design requirements. After the secondary lining layer 240 of the inverted arch solidifies, construct the frame column layer 250; among them, insert the column unit 252 into the corresponding assembly hole, assemble the cover plate 251 on the top of the column unit 252. After all the column units 252 and the cover plates 251 are assembled, then insert the first steel reinforcement cage into the column unit 252, lay a single-layer steel mesh on the cover plate 251, and finally pour the cover plate 251 and the column unit 252 integrally; among them, the cover plate 251 is reserved with casting holes corresponding to the column unit 252;

[0089] S5. After the concrete of the cover plate 251 solidifies, pour the secondary lining layer 120 of the arch wall, and then lay the road surface layer 260 on the top of the cover plate 251.

[0090] As a preferred embodiment, the frame column layer 250 in the step S4 is obtained through the following design steps:

[0091] S41. Obtain the design value of the axial pressure of the frame column layer 250 , unit: ;

[0092] S42. Determine the cross-sectional area of the column unit 252 according to the design value of the axial pressure , unit: ; ;

[0093] S43. Determine the cross-sectional area of the longitudinal main reinforcement of the column unit 252 according to the formula , unit: ; among them, ; is the longitudinal main reinforcement ratio of the column unit 252;

[0094] S44. According to the formula determine the allowable stress of the longitudinal tension ordinary reinforcement of the cover plate 251 value, unit: , where is the member force characteristic coefficient of the cover plate 251; is the non-uniform coefficient of longitudinal main reinforcement strain between cracks, is the elastic modulus of the reinforcement of the cover plate 251, unit: , is the distance from the outer edge of the outermost longitudinal main reinforcement to the bottom edge of the tension zone, unit: mm, is the equivalent diameter of the longitudinal main reinforcement, unit: mm, is the longitudinal main reinforcement ratio calculated according to the effective tension concrete cross-sectional area; when , take ; is the maximum crack width limit value of the cover plate 251, unit: mm. Considering the first-class highway load, the maximum allowable width for crack control requirements does not exceed 0.2 mm, and can be taken as 0.2 mm;

[0095] S45. According to the formula determine the maximum mid-span bending moment value of the cover plate 251, unit: , is the effective height of the cross-section of the cover plate 251, unit: m;

[0096] S46. According to the formula back-calculate the maximum span of the cover plate 251 under the action of vehicle load; where is the equivalent vehicle uniform load, unit: , is the vehicle concentrated load, unit: ;

[0097] S47. According to the formula calculate the distance from the resultant force point of the longitudinal main reinforcement to the tension edge of the cross-section, unit: mm; and according to the formula determine the relative compression zone height of the cross-section of the cover plate 251, unit: mm; where is the design value of the axial compressive strength of concrete, is the equivalent rectangular stress diagram coefficient of the concrete compression zone. For concrete C50 and below ; b takes the span per meter of the cover plate 251;

[0098] S48, according to the formula and Determine the minimum reinforcement area of the cover plate 251 that meets the requirements ,unit: , and then according to the minimum reinforcement area Determine the reinforcement method of the cover plate 251; wherein, is the design value of the tensile strength of the steel bar, unit: MPa, is the minimum reinforcement ratio of cover plate 251.

[0099] Furthermore, the step S41 specifically includes the following steps:

[0100] According to the formula Obtain the axial pressure design value of the frame column layer 250 ;in, is the deadweight of pavement layer 260, unit: , The self-weight of the frame column layer 250, unit: , It is the larger value of the deadweight load of the construction machinery during the construction period and the vehicle load during the operation period, unit: .

[0101] Furthermore, the step S42 specifically includes the following steps:

[0102] According to the formula Determine the cross-sectional area of the column unit 252 ,unit: ,in, is the axial pressure ratio limit, and d is the outer diameter of the column unit 252.

[0103] It is worth noting that the design method of the frame column layer 250 provided in this embodiment, the cross-sectional area of the column unit 252 obtained by the design steps is and cross-sectional area , according to the cross-sectional area and cross-sectional area The size and reinforcement of the column unit 252 required in the actual construction process can be determined, and the maximum span obtained through the design steps and minimum reinforcement area , the dimensions and reinforcement of the cover plate 251 required during the actual construction can be determined. In this way, the feasibility of the current construction plan can be clarified. By disclosing the specific dimension and reinforcement data, the standardization and regularization of related technologies can be promoted, which has direct guiding significance for actual construction, avoids construction errors, improves construction efficiency while ensuring the structural safety and durability, avoids blind selection during the actual process, reduces project waste, and ultimately promotes the standardization and popularization of technologies.

[0104] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. A lining structure applicable to mountain tunnels, characterized in that, It includes an arch wall lining assembly and an invert arch assembly, and the arch wall lining assembly and the invert arch assembly enclose to form an annular structure; wherein, the arch wall lining assembly includes an arch wall corrugated steel plate layer and an arch wall secondary lining layer which are arranged in sequence from outside to inside along the tunnel radial direction; wherein, the arch wall corrugated steel plate layer is provided with a first grouting hole and a first bolt hole for the first system bolt to penetrate through, and foamed concrete is injected into the interlayer space between the arch wall corrugated steel plate layer and the surrounding rock through the first grouting hole to form a first foamed concrete layer; The invert arch assembly includes an invert arch corrugated steel plate layer, an invert arch secondary lining layer, a frame column layer and a road surface layer which are arranged in sequence from bottom to top; wherein, The invert arch corrugated steel plate layer is provided with a second grouting hole and a second bolt hole for the second system bolt to penetrate through, and foamed concrete is injected into the interlayer space between the invert arch corrugated steel plate layer and the surrounding rock through the second grouting hole to form a second foamed concrete layer. The bottom of the frame column layer is embedded in the invert arch secondary lining layer, the road surface layer is laid on the top of the frame column layer, and the end of the invert arch corrugated steel plate layer is connected to the end of the arch wall corrugated steel plate layer; The arch wall corrugated steel plate layer includes a first corrugated steel plate main body and two first connection components respectively connected to the ends of the first corrugated steel plate main body. Each first connection component includes a first connection plate and a second connection plate. The first connection plate is connected to the bottom of the first corrugated steel plate main body, and the second connection plate is connected to the side of the first connection plate close to the invert arch corrugated steel plate layer. The second connection plate and the first connection plate form an L-shaped structure; The invert arch corrugated steel plate layer includes a second corrugated steel plate main body and two second connection components respectively connected to the ends of the second corrugated steel plate main body. Each second connection component includes a third connection plate, a fourth connection plate and a fifth connection plate which are arranged in parallel at intervals. The fourth connection plate is connected to the end of the second corrugated steel plate main body, the third connection plate is connected between the fourth connection plate and the fifth connection plate, and the third connection plate, the fourth connection plate and the fifth connection plate enclose to form a U-shaped structure with the opening facing downwards; wherein, the second connection plate is connected in the inner cavity of the U-shaped structure.

2. The lining structure applicable to mountain tunnels according to claim 1, characterized in that, The frame column layer includes a cover plate and a plurality of column units arranged at intervals. The lower end of each column unit is embedded in the invert arch secondary lining layer, the cover plate and the column units are integrally cast, and the cover plate is arranged on the top of the column units.

3. The lining structure applicable to mountain tunnels according to claim 1, characterized in that, The fourth connecting plate is provided with a first connecting hole for a bolt to penetrate through, the fifth connecting plate is provided with a second connecting hole corresponding to the first connecting hole, the second connecting plate is provided with a third connecting hole corresponding to the first connecting hole, a first water stop strip is arranged between the second connecting plate and the fourth connecting plate, and a second water stop strip is arranged between the second connecting plate and the fifth connecting plate. The second connecting plate is connected to the inner cavity of the U-shaped structure by a bolt penetrating through the first connecting hole, the second connecting hole and the third connecting hole. Both the first water stop strip and the second water stop strip are arranged on the side of the bolt close to the third connecting plate.

4. The lining structure applicable to mountain tunnels according to claim 1, characterized in that, It further includes a vertical drain pipe assembly and a central longitudinal drainage ditch. Among them, the central longitudinal drainage ditch is arranged at the bottom center of the second corrugated steel plate body and is used to collect the surrounding rock seepage water drained from the outer wall of the second corrugated steel plate body. The vertical drain pipe assembly includes a plurality of vertical drain pipes arranged at intervals along the extension direction of the central longitudinal drainage ditch. Each vertical drain pipe sequentially penetrates through the second corrugated steel plate body and the inverted arch secondary lining layer from bottom to top and enters the interval space of the column unit. The bottom of the vertical drain pipe is communicated with the central longitudinal drainage ditch.

5. The lining structure applicable to mountain tunnels according to claim 3, characterized in that The second connecting plate is provided with a drain hole facing the second corrugated steel plate body at a position below the fourth connecting plate.

6. A construction method for a lining structure applicable to mountain tunnels, which is applied to the lining structure described in any one of claims 4-5, and is characterized in that, It includes the following steps: S1. After excavating the tunnel chamber, assemble the arch wall corrugated steel plate layer, inject foamed concrete through the first grouting hole on the back of the arch wall corrugated steel plate layer to form a first foamed concrete layer, and then drive the first system anchor bolts through the first anchor bolt holes. S2. After excavating the inverted arch, first excavate the central longitudinal drainage ditch at the center of the arch bottom, fill the airbag in the central longitudinal drainage ditch, then assemble the inverted arch corrugated steel plate layer, and then connect the end of the inverted arch corrugated steel plate layer to the end of the arch wall corrugated steel plate layer. S3. Inject foamed concrete through the second grouting hole at the bottom of the inverted arch corrugated steel plate layer to form a second foamed concrete layer, and then drive the second system anchor bolts through the second anchor bolt holes. After the foamed concrete solidifies, pierce the airbag through the vertical drain pipe. S4. Pour the inverted arch secondary lining layer, and reserve assembly holes on the top surface of the inverted arch secondary lining layer according to the design requirements. After the inverted arch secondary lining layer solidifies, construct the frame column layer. Among them, insert the column unit into the corresponding assembly holes, assemble the cover plate on the top of the column unit. After all the column units and cover plates are assembled, insert the first steel reinforcement cage into the column unit, lay a single-layer steel mesh on the cover plate, and finally pour the cover plate and the column unit integrally. Among them, the cover plate is reserved with casting holes corresponding to the column units. S5. After the concrete of the cover plate solidifies, pour the arch wall secondary lining layer, and then lay the road surface layer on the top of the cover plate.

7. The construction method of the lining structure applicable to mountain tunnels according to claim 6, characterized in that, The frame column layer in step S4 is obtained through the following design steps: S41, obtain the design value of the axial pressure of the frame column layer ; S42, according to the design value of the axial pressure determine the cross-sectional area of the column unit ; S43. Determine the cross-sectional area of the longitudinal main reinforcement bars of the column unit according to the formula ; where is the longitudinal main reinforcement ratio of the column unit; ​ S44. Determine the allowable stress of the longitudinal tension ordinary steel bars of the cover plate according to the formula value; where is the member force characteristic coefficient of the cover plate; is the coefficient of non-uniformity of longitudinal main bar strain between cracks, is the elastic modulus of the steel bars of the cover plate, is the distance from the outer edge of the outermost longitudinal main bar to the bottom edge of the tension zone, is the equivalent diameter of the longitudinal main bar, is the longitudinal main bar reinforcement ratio calculated according to the effective tension concrete cross-sectional area; when take ; is the maximum crack width limit value of the cover plate;​ S45, determine the maximum mid-span bending moment value of the cover plate according to the formula wherein , is the effective height of the cross-section of the cover plate; S46, calculate the maximum span of the cover plate under the action of vehicle load by reverse calculation according to the formula ; where is the equivalent uniform vehicle load, and is the concentrated vehicle load S47, according to the formula calculate the distance from the resultant force point of longitudinal main reinforcement to the tension edge of the section ; and according to the formula determine the relative depth of the compression zone of the cover plate section ; where is the design value of the axial compressive strength of concrete, is the coefficient of the equivalent rectangular stress diagram of the concrete compression zone, and b is taken as the span per meter of the cover plate; S48, determine the minimum reinforcement area of the cover plate that meets the requirements according to the formula and , and then determine the reinforcement method of the cover plate according to the minimum reinforcement area ; where is the design value of the tensile strength of the steel bar, and is the minimum reinforcement ratio of the cover plate 8. The construction method of the lining structure applicable to mountain tunnels according to claim 7, characterized in that Step S41 specifically includes the following steps: According to the formula obtain the design value of the axial pressure of the frame column layer ; where is the self-weight of the road surface layer, is the self-weight of the frame column layer, is the larger value between the self-weight load of construction machinery during construction and the vehicle load during operation.

9. The construction method of the lining structure applicable to mountain tunnels according to claim 7, characterized in that, Step S42 specifically includes the following steps: According to the formula to determine the cross-sectional area of the column unit , unit: , where is the axial compression ratio limit, and d is the outer diameter of the column unit.

Images