Lining structure for tunnel, construction method and tunnel

Abstract

The present application discloses a lining structure for a tunnel. The lining structure includes an initial support layer and an assembled lining layer in sequence from the outer surrounding rock in the tunnel to the interior of the tunnel, wherein the initial support layer is arranged close to the surrounding rock; and the assembled lining layer is arranged on the inner side of the initial support layer and is 40 to 60 cm away from the initial support layer, wherein the assembled lining layer has an outer surface facing the initial support layer and an inner surface facing the interior of the tunnel, and a sprayed waterproof layer is attached to the outer surface of the assembled lining layer to form an integral waterproof layer. The lining structure of the present application achieves a good waterproof effect by spraying an integral sprayed waterproof layer on the outer surface of the assembled lining layer, and the off-wall structure is also convenient for later inspection and maintenance. In addition, the assembled lining layer is obtained by assembling pre-made lining blocks and is easy to disassemble and replace.

Description

Technical Field

[0001] The present invention belongs to the technical field of tunnel traffic engineering, and in particular relates to a lining structure for a tunnel, a construction method and a tunnel. Background Art

[0002] Currently, tunnels constructed using the mining method in China primarily utilize composite linings, with shotcrete anchor support used for primary support and cast-in-place lining for secondary lining. A waterproof layer is installed between the primary support and secondary lining. Drainage blind pipes (plates) are installed on the outside of the waterproofing board to drain to lateral longitudinal blind pipes, which are then channeled to sidewall ditches. While this process is mature and widely used, it still presents various issues, including widespread leakage, difficulty maintaining the drainage system, and difficulty ensuring the quality of the secondary lining.

[0003] Although drainage blind pipes and waterproof panels are installed between the tunnel's primary support and secondary lining, and water-stopping measures are taken at the lining and joints, lining leakage is common due to various reasons, including construction technology. At the same time, because the drainage blind pipe is located behind the secondary lining, it is common to become clogged due to calcification and groundwater-carrying sediment. Once the secondary lining is poured, the blockage in the drainage blind pipe is difficult to clear. Furthermore, currently, the secondary lining is generally constructed after the primary support has stabilized. The stress level of the secondary lining is mostly assumed to bear part or even all of the loose load in the event of failure of the primary support. However, measured data shows that the stress on the secondary lining is generally small. Furthermore, because the secondary lining is cast integrally using a mold, it is difficult to remove and replace, and the construction period is long. Summary of the Invention

[0004] In view of this, the main purpose of the present invention is to provide a wall-mounted lining structure, which realizes the spraying of an integral spray film waterproof layer on the outer surface of the lining layer, thereby achieving a good waterproof effect, and the wall-mounted structure is also convenient for later inspection and maintenance.

[0005] In a first aspect of the present invention, a lining structure for a tunnel is provided, wherein the lining structure comprises an initial support layer and an assembled lining layer in sequence from the outer surrounding rock in the tunnel to the interior of the tunnel, wherein:

[0006] The initial support layer is arranged close to the surrounding rock; and

[0007] The assembled lining layer is arranged on the inner side of the initial supporting layer and is 40 to 60 cm away from the initial supporting layer, wherein the assembled lining layer has an outer surface facing the initial supporting layer and an inner surface facing the interior of the tunnel, and a sprayed waterproof layer is attached to the outer surface of the assembled lining layer to form an integral waterproof layer.

[0008] The present invention utilizes an off-wall design, allowing for a convenient spray-coated, integral spray-coated waterproof layer on the outer surface of the assembled lining. The spray-coated waterproof layer in this application is a single, integral waterproof layer, devoid of seams, resulting in excellent waterproofing effectiveness. Furthermore, due to the off-wall design between the lining and the supporting layer, seepage water in the tunnel is collected by the integrally formed waterproof layer. Therefore, the present invention achieves excellent waterproofing effectiveness simply by providing the spray-coated waterproof layer, eliminating the need for drainage blind pipes. In comparison, spraying the spray-coated waterproof layer on the inner surface of the lining allows seepage water from the surrounding rock of the tunnel to flow through the lining, where it is collected by the spray-coated waterproof layer and then discharged from the tunnel. Over time, this seepage water can erode the lining and reduce its strength. Therefore, spraying the spray-coated waterproof layer on the outer surface of the lining provides superior waterproofing effectiveness compared to applying the spray-coated waterproof layer on the inner surface of the lining. Furthermore, the gap between the initial supporting layer and the assembled lining layer allows for timely repair of any damage to the waterproof layer.

[0009] According to one embodiment of the present invention, the lining structure further comprises positioning anchor rods arranged radially along the tunnel arc for positioning each lining block when constructing the assembled lining layer. Preferably, each lining block in the assembled lining layer is positioned by at least four of the positioning anchor rods.

[0010] According to one embodiment of the present invention, the lining structure further includes drainage channels at the arch feet between the initial support layer and the assembled lining layer on both sides of the tunnel along the longitudinal direction of the tunnel, for draining water collected by the sprayed waterproof layer.

[0011] According to one embodiment of the present invention, the assembled lining layer is further provided with an inspection door.

[0012] The assembled lining layer is provided with access doors at regular intervals. The spacing and number of access doors can be determined based on the specific circumstances. During tunnel construction, the access doors can be used for the application of the sprayed waterproofing layer. After the tunnel is completed, the access doors can serve as inspection and maintenance access for the tunnel.

[0013] According to one embodiment of the present invention, the lining structure further comprises a monitoring system, which is arranged between the initial support layer and the assembled lining layer and is used for monitoring water leakage and displacement deformation of the tunnel.

[0014] The monitoring system can be configured according to operational needs. For example, the monitoring system can be used for water leakage monitoring and displacement deformation monitoring, but is not limited thereto. Inductive optical fibers and inspection robots can be used to improve the accuracy of monitoring results and the degree of automation of the monitoring process.

[0015] According to one embodiment of the present invention, the lining structure further comprises a lighting system, which is arranged between the initial support layer and the assembled lining layer. Specifically, the lighting system can adopt fixed lighting or movable lighting.

[0016] A second aspect of the present invention provides a construction method for constructing the lining structure, the construction method comprising the following steps:

[0017] Inside the tunnel, an initial support layer is arranged close to the surrounding rock;

[0018] Assembling prefabricated lining blocks at a distance of 40 to 60 cm from the initial support layer to construct an assembled lining layer; and

[0019] An integral spray membrane waterproof layer is formed by spraying on the outer surface of the assembled lining layer toward the initial supporting layer.

[0020] According to one embodiment of the present invention, the assembling step and the spraying step are substantially performed simultaneously. In this case, the spraying step can be performed manually or by a robot; preferably, the spraying step is performed by a robot.

[0021] According to one embodiment of the present invention, after the initial support layer is arranged, positioning anchor rods for positioning each lining block are arranged along the radial direction of the tunnel arc, wherein one end of the positioning anchor rod passes through the initial support layer and is inserted into the surrounding rock, and the other end extends a certain length outside the initial support layer.

[0022] According to one embodiment of the present invention, each lining block is positioned by at least four of the aforementioned positioning anchors. The assembled lining layer described herein is assembled from a number of prefabricated lining blocks, which are essentially cast from concrete. The specific shape, size, number of blocks, and assembly method of the lining blocks are not restricted. In principle, any existing assembled lining blocks can be used to construct the assembled lining layer described herein. For example, the maximum number of positioning anchors required to position each lining block depends on the shape and size of the specific lining block, for example, four to eight. Furthermore, the maximum number of positioning anchors required to position each lining block also takes into account cost and efficiency. Preferably, each lining block is positioned by four of the aforementioned positioning anchors. Adjacent lining blocks can be positioned by different positioning anchors or by the same positioning anchor. Specifically, whether adjacent lining blocks can share the same positioning anchor depends on the specific shape and size of the lining blocks. Since the positioning anchor rod is in a humid environment for a long time and is in contact with moisture and air, according to a preferred embodiment of the present invention, the positioning anchor rod is a corrosion-resistant anchor rod.

[0023] According to one embodiment of the present invention, the certain length generally does not exceed the distance from the inner surface of the initial supporting layer facing the interior of the tunnel to the inner surface of the assembled lining layer facing the interior of the tunnel.

[0024] A third aspect of the present invention provides a tunnel comprising the aforementioned lining structure. This lining structure is primarily used in areas with favorable geological conditions for mining-based construction. After tunnel excavation, the surrounding rock requires minimal or no support to form a stable load-bearing system. This lining structure is particularly suitable for highway tunnels with stable surrounding rock, subway tunnels, and municipal tunnels for electrical wires, cables, heating systems, and hot water systems.

[0025] The tunnel lining structure of the present invention achieves excellent waterproofing by spraying a film-sprayed waterproof layer onto the outer surface of the assembled lining layer. Its off-wall structure also facilitates later repair and maintenance. Furthermore, the assembled lining layer is formed by assembling prefabricated lining blocks, making it easy to remove and replace. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic cross-section of conventional composite lining;

[0027] Figure 2 A schematic cross-sectional view of a lining structure according to an embodiment of the present invention;

[0028] The figure includes: 11-initial support structure; 12-waterproof layer; 13-secondary lining structure; 14-anchor rod; 21-initial support layer; 22-sprayed waterproof layer; 23-assembled lining layer; 24-positioning anchor rod; 25-drainage channel. DETAILED DESCRIPTION

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention and the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] The present invention will be further described below with reference to the schematic examples shown in the accompanying drawings. The advantages of the present invention will become more apparent from the following description. Like reference numerals in the accompanying drawings refer to like components. The shapes and dimensions of the components in the schematic drawings are for illustration only and should not be considered to reflect actual shapes, dimensions, or absolute positions.

[0031] Figure 1 This is a schematic cross-sectional diagram of a conventional composite lining. Figure 1The tunnel includes an initial support structure 11, a waterproof layer 12 and a secondary lining structure 13 from the outer surrounding rock in the tunnel to the inside of the tunnel. In addition, it includes anchor rods 14 arranged radially along the arc of the tunnel, which are used to reinforce the initial support structure 11 and support the surrounding rock, increase the friction between soil layers, and form a "combined beam" and "suspension" effect.

[0032] See also Figure 1 , the structural layer that is constructed immediately after the tunnel is excavated and serves as part of the permanent load-bearing structure is the initial support structure 11. The role of the initial support structure 11 in the tunnel is to control the appropriate release and deformation of the surrounding rock stress, increase the structural safety and facilitate construction. In the construction method of the initial support structure 11, first of all, the pumice should be removed, and then the initial spraying of concrete should be carried out immediately to seal the surrounding rock to give full play to the self-stabilizing ability of the surrounding rock; secondly, according to the level of the surrounding rock, systematic support construction should be carried out; finally, the concrete should be sprayed again to the pre-designed thickness. Among them, in the construction method of the initial support structure 11, according to the characteristics of the surrounding rock, the size of the section and the conditions of use, single or combined support forms such as sprayed concrete, anchor rods, steel mesh and steel frame can be selected.

[0033] Currently, tunnels constructed using the mining method in China primarily employ composite linings. As shown in the figure, a waterproof layer 12 is installed between the primary support structure 11 and the secondary lining structure 13. Tunnel waterproofing generally consists of various components, including geotextiles, geotextile-wrapped annular (longitudinal) blind pipes, and waterproof panels.

[0034] Conventional composite lining construction is relatively complex. First, a geotextile is laid on the inner surface of the tunnel's primary support structure, facing the tunnel interior. This geotextile prevents collapse of the primary support structure and filters water seeping from the surrounding rock, preventing calcified crystals and sediment carried by the water from clogging blind pipes.

[0035] Subsequently, the waterproof sheet in the waterproof layer is laid on the side of the secondary lining structure facing the primary support structure to separate water from the secondary lining structure and prevent water from penetrating into the secondary lining structure and affecting its strength.

[0036] Finally, the waterproof layer includes several circumferential blind pipes, spaced longitudinally along the tunnel between the waterproof sheet and the geotextile. Between the circumferential blind pipes are several longitudinal blind pipes, spaced longitudinally along the tunnel. Each longitudinal blind pipe is connected to every other circumferential blind pipe. Both the circumferential and longitudinal blind pipes are wrapped in geotextiles to filter water flowing into them and prevent them from clogging. Water leaking between the primary support structure and the secondary lining is filtered through the geotextiles before flowing into the circumferential and longitudinal blind pipes. From there, it flows into the side ditches and ultimately out of the tunnel.

[0037] Although existing tunnels are equipped with waterproof panels in their waterproof layers and water-stopping measures are implemented in the lining and joints, water leakage is common due to various reasons, including construction techniques. Furthermore, although the leaking water in the tunnel is filtered by the geotextile, over time, the circumferential (longitudinal) blind pipes are inevitably clogged by the calcified crystals and sediment carried by the leaking water. Once the secondary lining structure is cast, it cannot be removed or replaced. However, due to the geotextile, circumferential (longitudinal) blind pipes, and waterproof panels already laid between the primary support structure and the secondary lining structure, the gap between them is narrow. Once the circumferential (longitudinal) blind pipes become clogged, they are difficult to clear.

[0038] In order to solve at least one of the above problems existing in conventional lining structures, the present invention provides a spray-film waterproof off-wall lining structure. Figure 2 , which shows a cross-sectional schematic diagram of a lining structure according to an embodiment of the present invention. Figure 2 The tunnel is formed from the outer surrounding rock to the inside of the tunnel, and includes an initial support layer 21, an assembled lining layer 23, and a sprayed waterproof layer 22 attached to the outer surface of the assembled lining layer 23.

[0039] like Figure 2 As shown, the primary support layer 21 is arranged close to the surrounding rock, and the assembled lining layer 23 is arranged inside the primary support layer 21. A gap is reserved between the assembled lining layer 23 and the primary support layer 21. The thickness of this gap must meet the space requirements for subsequent activities such as spraying waterproofing, operational maintenance, and health monitoring. Typically, the average distance between the assembled lining layer and the primary support layer can be 40 to 60 cm. Because the inner surface of the primary support layer facing the tunnel interior is not completely flat, when the inner surface of the primary support layer 21 facing the tunnel interior is convex, the distance between the assembled lining layer 23 and the primary support layer 21 may be less than 40 cm; when the inner surface of the primary support layer 21 facing the tunnel interior is concave, the distance between the assembled lining layer 23 and the primary support layer 21 may be greater than 60 cm. More preferably, the average distance between the assembled lining layer 23 and the primary support layer 21 can be approximately 50 cm.

[0040] At the same time, the assembled lining layer 23 is assembled from a number of prefabricated lining blocks, which are basically cast from concrete. The shape, number of blocks, and assembly method of the specific lining blocks are not restricted. In principle, all existing assembled lining blocks can be used to construct the assembled lining layer 23 in this application. The assembled lining layer 23 itself basically does not bear the surrounding rock load and can give full play to the self-bearing function of the surrounding rock. It is mainly used in areas with good geological conditions for mining construction. After tunnel excavation, the surrounding rock does not require support or only requires a small amount of support to form a stable force system; it is particularly suitable for highway tunnels, subway tunnels, and municipal tunnels such as those for electric wires, cables, heating, and hot water with good surrounding rock stability.

[0041] In addition, since the assembled lining layer 23 in the present application adopts a prefabricated assembled structure, it is easy to disassemble and replace; and the material of the lining block itself is non-flammable, it can be directly used as a fireproof board for tunnels with high fire protection requirements.

[0042] The spray film waterproof layer 22 can adopt any suitable formula and spraying form. Generally, a two-component main liquid can be prepared according to the formula of the film-forming material. When spraying, it is separately delivered to the spray gun. The two liquids mix in the air and undergo polymerization reaction to quickly form a waterproof film layer with a certain strength and toughness. In principle, all existing spray film waterproof materials can be used to form the spray film waterproof layer 22 in this application. For example, the spray film waterproof layer 22 can be formed by the reaction of an acrylate main liquid and an initiator. The film material has uniform quality, can be formed as a whole in one go, and is environmentally friendly and flame retardant. By adding a silicate aqueous solution to the above-mentioned acrylate spray film waterproof material, the durability and corrosion resistance of the film material can be improved; by adding natural rubber, the tensile properties of the film material and its adsorption properties to concrete can be improved; and by adding flaky nano-expanded graphite as a filler, the waterproof performance of the film material can be further improved.

[0043] Figure 2 The lining structure of the present invention shown also includes a positioning anchor rod 24. The positioning anchor rod 24 is arranged along the radial direction of the tunnel arc, and is used to position each lining block when constructing the assembled lining layer 23. One end of the positioning anchor rod 24 passes through the initial support layer 21 and is inserted into the surrounding rock, and the other end extends a certain length inside the initial support layer 21. On the one hand, after the positioning anchor rod 24 is inserted into the surrounding rock, it can be used to support and reinforce the surrounding rock, increase the friction between soil layers, and form a "composite beam" and "suspension" effect. On the other hand, one end of the positioning anchor rod 24 passes through the initial support layer 21 and is inserted into the surrounding rock, and the other end extends a certain length inside the initial support layer 21 for positioning and assembling each lining block in the assembled lining layer 23.

[0044] like Figure 2As shown, the lining structure of the present invention also includes drainage channels 25, which are arranged along the longitudinal direction of the tunnel and located at the arch foot between the initial support layer 21 and the assembled lining layer 23 on both sides of the tunnel. These channels are used to drain water collected by the sprayed waterproof layer 22. Leakage water in the tunnel surrounding rock seeps through the initial support layer 21 and drips onto the sprayed waterproof layer 22, gradually flowing from the arch top to the sides and converging into the drainage channels 25 at the arch foot, before being discharged from the tunnel. Furthermore, since the drainage channels 25 are arranged between the initial support layer 21 and the assembled lining layer 23 on both sides of the tunnel, they can also be used as maintenance channels.

[0045] For convenient maintenance, especially for longer tunnels, the lining structure of the present invention may further include maintenance doors (not shown). The maintenance doors may be arranged at appropriate positions of the assembled lining layer 23 as required, and the spacing between the maintenance doors and the number of maintenance doors may be determined according to the specific circumstances.

[0046] The construction method for constructing the sprayed waterproof prefabricated assembled off-wall lining structure of the present invention may include the following steps: arranging an initial support layer close to the surrounding rock inside the tunnel; assembling prefabricated lining blocks at a distance of 40 to 60 cm from the initial support layer to construct an assembled lining layer; and spraying an integral sprayed waterproof layer on the outer surface of the assembled lining layer facing the initial support layer.

[0047] According to one embodiment, specifically, first, conventional drilling and blasting construction technology is used to excavate the tunnel, and an initial support layer is arranged inside the tunnel close to the surrounding rock; positioning anchor rods are arranged along the radial direction of the tunnel arc, wherein one end of the positioning anchor rod is inserted through the initial support layer into the surrounding rock, and the other end is extended to a certain length inside the initial support layer; water leakage remediation measures are taken to ensure that there is no dripping water leakage on the surface of the initial support layer, wherein the water leakage remediation measures include grouting, leakage diversion, leakage plugging and interception and drainage; the surrounding rock stability is evaluated based on the monitoring and measurement data, and the internal clearance detection is carried out on the stable section to ensure that the internal contour meets the design requirements and that there is sufficient space after the off-wall lining is installed.

[0048] Secondly, a monitoring system will be laid to monitor water leakage and displacement deformation in the tunnel; and a lighting system will be laid.

[0049] Then, after checking that the lining blocks in the assembled lining layer meet the flatness requirements, use positioning anchors to assemble the pre-made lining blocks at a distance of 40 to 60 cm from the initial support layer to construct the assembled lining layer. Each lining block is positioned by 4 of the positioning anchors; inspection doors are set at a certain interval on the side walls of the assembled lining layer.

[0050] Finally, utilizing the gap between the inspection door and the initial support layer and the assembled lining layer, a spraying robot is used to perform spray membrane waterproofing construction on the outer surface of the assembled lining layer facing the initial support layer to form an overall spray membrane waterproofing layer.

[0051] During the operation of the tunnel, the inspection door can be used as a monitoring channel and a defect remediation channel. If the defect is serious, the off-wall lining can be partially dismantled, reinforced and then relined.

[0052] The lining structure of the present invention achieves excellent waterproofing by spraying a monolithic sprayed waterproof layer onto the outer surface of the assembled lining layer. Compared to conventional composite linings, this eliminates the need for complex drainage structures such as circumferential (longitudinal) blind pipes. Furthermore, the assembled lining layer is constructed by assembling prefabricated lining blocks, making it easy to remove and replace.

[0053] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present description and drawings under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A lining structure for a tunnel, characterized in that: The lining structure includes an initial support layer and an assembled lining layer from the outer surrounding rock in the tunnel to the inside of the tunnel, wherein: The initial support layer is arranged close to the surrounding rock; and The assembled lining layer is arranged inside the initial support layer and is 40 to 60 cm away from the initial support layer, wherein the assembled lining layer has an outer surface facing the initial support layer and an inner surface facing the interior of the tunnel, and a sprayed waterproof layer is attached to the outer surface of the assembled lining layer to form an integral waterproof layer; the assembled lining layer is assembled from a plurality of lining blocks; The lining structure also includes positioning anchor rods arranged radially along the tunnel arc for positioning each lining block when constructing the assembled lining layer; one end of the positioning anchor rod passes through the initial support layer and is inserted into the surrounding rock, and the other end extends a certain length from the inner side of the initial support layer, for positioning and assembling each lining block in the assembled lining layer.

2. The lining structure according to claim 1, characterized in that: Each lining block in the assembled lining layer is positioned by at least four positioning anchor rods.

3. The lining structure according to claim 1, wherein: The lining structure further comprises drainage channels arranged at the arch feet between the initial support layer and the assembled lining layer on both sides of the tunnel along the longitudinal direction of the tunnel, for draining water collected by the sprayed waterproof layer.

4. The lining structure according to claim 1, wherein: The assembled lining layer is also provided with an inspection door.

5. The lining structure according to claim 1, wherein: The lining structure further comprises a monitoring system, which is arranged between the initial support layer and the assembled lining layer and is used for monitoring water leakage and displacement deformation of the tunnel.

6. The lining structure according to claim 1, wherein: The lining structure further includes a lighting system, which is arranged between the initial support layer and the assembled lining layer.

7. A construction method for constructing a lining structure according to any one of claims 1 to 6, characterized in that: The construction method comprises the following steps: Inside the tunnel, an initial support layer is arranged close to the surrounding rock; Assembling prefabricated lining blocks at a distance of 40 to 60 cm from the initial support layer to construct an assembled lining layer; and An integral spray membrane waterproof layer is formed by spraying on the outer surface of the assembled lining layer toward the initial supporting layer.

8. The construction method according to claim 7, wherein: The assembling step and the spraying step are performed substantially simultaneously.

9. The construction method according to claim 7, wherein: After arranging the initial support layer, positioning anchor rods for positioning each lining block are arranged along the radial direction of the tunnel arc, wherein one end of the positioning anchor rod passes through the initial support layer and is inserted into the surrounding rock, and the other end extends a certain length from the inside of the initial support layer.

10. The construction method according to claim 9, characterized in that: Each lining block is positioned by at least four positioning anchor rods.

11. A tunnel, characterized in that: The invention comprises the lining structure according to any one of claims 1 to 6.

Images