Tunnel off-wall heat insulation lining structure and construction method

Abstract

The present application relates to a kind of tunnel off-wall heat insulation lining structure and construction method, including primary support and secondary lining from outside to inside, gap exists between primary support and secondary lining and forms empty layer;Empty layer includes steel frame, square wood and panel from outside to inside;Steel frame is annular arch, multiple are uniformly arranged longitudinally, and fixed in the inside of primary support;Square wood is longitudinally arranged, multiple are uniformly arranged annularly, and fixed in the inside of steel frame;Panel is cambered panel, after being annularly spliced into ring, it is longitudinally spliced, and fixed in the inside of square wood;Steel frame, square wood and panel form the outside pouring mold plate of secondary lining.The present application utilizes the air in empty layer to carry out heat insulation, and has waterproof and drainage function, the overall structure of steel frame, square wood and panel is directly used as the outside pouring mold plate of secondary lining, so personnel is not needed to enter and carry out formwork construction, the thickness of empty layer is greatly reduced, and the pouring construction process of secondary lining is optimized.

Description

Technical Field

[0001] This invention relates to the field of tunnel engineering construction technology, specifically to a tunnel detached heat-insulating lining structure and construction method. Background Technology

[0002] Tunnel insulation lining is used in both cold-region and high-temperature tunnels. Based on the method of laying the insulation layer, it is often classified into sandwich, attached-wall, and separate-wall lining structures. Sandwich lining involves laying a solid insulation layer between the initial support and the secondary lining. This insulation layer needs to withstand the contact pressure between the initial support and the secondary lining, thus requiring high compressive strength. Furthermore, it is difficult to repair or replace if it fails. Attached-wall lining, with the solid insulation layer laid close to the inner surface of the secondary lining, offers advantages such as convenient installation and easy replacement and maintenance. However, the insulation layer is generally made of lightweight, low-strength materials, which may break and fall off, limiting its use in harsh environments, such as high-speed railway tunnels. The detached lining utilizes an air gap to achieve thermal insulation, which can overcome the defects caused by the solid insulation layer. There are different options for the location of the air gap. It can be modified by adding an air gap between the secondary lining and the solid insulation layer to form a detached lining. Alternatively, an air gap can be set between the initial support and the secondary lining.

[0003] However, in existing off-wall lining construction, workers need to enter the interior to erect formwork, thus requiring consideration of personnel movement and operational space. When used in cold-region tunnels, groundwater freezing can cause frost heave pressure behind the secondary lining, leading to destructive freeze-thaw cycles. In high-temperature tunnels, hot water can penetrate the initial support, soaking the secondary lining and penetrating weak points, construction joints, or expansion joints, resulting in hot water leakage within the tunnel's arch wall area.

[0004] Therefore, it is necessary to propose new measures to overcome the above-mentioned shortcomings. Summary of the Invention

[0005] The purpose of this invention is to provide a tunnel detached thermal insulation lining structure and construction method to solve the problems of existing technologies, such as the need to consider the operating space for personnel to walk and work, the existence of freeze-thaw cycle damage, and hot water leakage.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A tunnel detached thermal insulation lining structure is provided, the structure including an initial support and a secondary lining from the outside to the inside, and a gap exists between the initial support and the secondary lining to form a void layer;

[0008] The air gap layer includes, from the outside to the inside, a steel frame, square timber, and panels; the steel frame is a circumferential arch frame, with multiple frames evenly arranged longitudinally and fixed to the inner side of the initial support; the square timber is arranged longitudinally, with multiple frames evenly arranged circumferentially and fixed to the inner side of the steel frame; the panels are arc panels, spliced ​​circumferentially into a ring and then spliced ​​longitudinally, and fixed to the inner side of the square timber.

[0009] The steel frame, the square timber, and the panel constitute the outer pouring template for the secondary lining.

[0010] Furthermore, the inner side of the initial support is provided with exposed short steel bars, and the steel frame is fixed to the short steel bars.

[0011] Furthermore, longitudinally arranged air gap water channels are provided at the bottom of the circumferential sides within the air gap, and the air gap water channels are connected to the water channels inside the tunnel through horizontally arranged blind pipes.

[0012] Furthermore, a waterproof membrane is provided on the inner side of the panel, and the waterproof membrane is located on the outer side of the secondary lining.

[0013] Furthermore, a geotextile is provided between the panel and the waterproof membrane.

[0014] On the other hand, a construction method for a tunnel off-wall thermal insulation lining structure is provided, the method comprising:

[0015] Excavating a tunnel;

[0016] Initial construction support;

[0017] In the initial support ring, longitudinal drainage ditches are made on the inner side of the bottom on both sides, and horizontal blind pipes are pre-installed.

[0018] A circumferentially arched steel frame is fixed inside the initial support, with multiple steel frames evenly arranged longitudinally.

[0019] Longitudinal square timbers are tied to the inside of the steel frame, with multiple square timbers evenly arranged in a circumferential direction.

[0020] A panel is fixed inside the square timber. Multiple panels are spliced ​​together circumferentially to form a ring, and then spliced ​​longitudinally to wrap the drainage ditch of the void layer between the panel and the initial support.

[0021] The integral structure composed of steel frame, square timber and panel is used as the outer pouring template of the secondary lining, and the tunnel concrete pouring trolley is erected as the inner pouring template of the secondary lining. Concrete is poured to construct the secondary lining.

[0022] Furthermore, the method also includes:

[0023] A waterproof membrane is laid on the inner surface of the panel, and the overall structure composed of the steel frame, square timber, panel and waterproof membrane is used as the outer pouring template for the secondary lining.

[0024] Furthermore, the method also includes:

[0025] The geotextile is fixed to the inner surface of the panel with nails, and the waterproof membrane is fixed to the inner surface of the geotextile.

[0026] Furthermore, the method also includes:

[0027] The nail has a plastic washer, and the waterproof membrane is welded to the plastic washer by a hot melt welding process, thereby fixing it to the inside of the panel.

[0028] Furthermore, the method also includes:

[0029] Construct a tunnel drainage ditch inside the tunnel and connect a pre-installed blind pipe to the tunnel drainage ditch.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] This invention provides a tunnel detached-wall thermal insulation lining structure and construction method, utilizing the sealed air in the detached layer for thermal insulation. It can be used in applications requiring thermal insulation, such as tunnels in cold regions and high-temperature tunnels. Unlike traditional detached-wall structures where personnel must enter for formwork construction, this invention eliminates the need for personnel, allowing for the use of smaller steel frames and timber, significantly reducing the thickness of the detached layer and saving space. It also serves as both thermal insulation and an outer formwork for concrete pouring. In cold-region tunnels, the detached layer provides space to accommodate the expansion of frozen groundwater, reducing frost heave pressure behind the secondary lining and mitigating the destructive effects of freeze-thaw cycles. In high-temperature tunnels, the detached layer prevents hot water from seeping into the initial support and soaking the secondary lining, further avoiding the risk of hot water penetrating weak points, construction joints, or expansion joints in the secondary lining, thus preventing hot water leakage within the tunnel's arch wall area. Furthermore, in this invention, hot water from the detached layer collects in a detached-wall drainage ditch and is then channeled into the tunnel's internal drainage system, achieving effective collection and discharge of high-temperature seepage. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained from these drawings without creative effort.

[0033] Figure 1This is a cross-sectional view of the tunnel wall-separated thermal insulation lining structure provided in an embodiment of the present invention.

[0034] Figure 2 yes Figure 1 The sample image of size A in the image.

[0035] Figure 3 yes Figure 1 Section I-I in the diagram.

[0036] Figure 4 yes Figure 1 The B-size sample diagram in the image.

[0037] The diagram is marked as follows:

[0038] 1-Surrounding rock, 2-Initial support, 3-Void layer, 4-Secondary lining, 5-Steel frame, 6-Square timber, 7-Panel, 8-Geotextile, 9-Waterproof membrane, 10-Void layer drainage ditch, 11-Drainage ditch inside the tunnel, 12-Blind pipe. Detailed Implementation

[0039] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0040] In the description of this invention, it should be understood that the terms "top", "bottom", "inner", "outer", "longitudinal", "lateral", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0041] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connection," "setting," etc., should be interpreted broadly. For example, they can refer to a fixed connection or setting, a detachable connection or setting, or an integral connection or setting. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0042] It should also be noted that although the order of steps is mentioned in the method description, in some cases, steps may be performed in a different order than that described here, and this should not be interpreted as a restriction on the order of steps.

[0043] In this specific implementation, the tunnel length direction is defined as longitudinal, the direction perpendicular to it is defined as transverse, and the tunnel cross-sectional profile is defined as circumferential. Furthermore, the area near the surrounding rock is defined as the outer side, and the area near the tunnel interior is defined as the inner side.

[0044] This invention provides a tunnel detached heat insulation lining structure, which constructs a special sandwich structure between the initial support 2 and the secondary lining 4, playing the roles of heat insulation and drainage. It can replace the existing detached lining with a solid heat insulation layer, effectively avoiding the technical defects of the existing detached lining, and is suitable for working conditions such as cold region tunnels and high ground temperature tunnels that require heat insulation.

[0045] Specifically, such as Figure 1-3 In this embodiment, the tunnel detached thermal insulation lining structure is constructed inside the excavated surrounding rock 1, and includes, from the outside to the inside, initial support 2 and secondary lining 4. The initial support 2 and secondary lining 4 are spaced a certain distance apart to form a gap of a certain thickness, thus forming a void layer 3. The void layer 3 has a special structural layout, including, from the outside to the inside, a steel frame 5, square timber 6, and a panel 7.

[0046] in:

[0047] The steel frame 5 is a circumferential arch frame, with multiple arches evenly arranged longitudinally. Various cross-sectional steel materials can be selected, such as channel steel, I-beams, and H-beams. Figure 3 In this embodiment, channel steel is used. The steel frame 5 is fixed to the inner side of the initial support 2 and is tightly attached to the wall surface of the initial support 2. Considering that the surface of the initial support 2 is uneven, short steel bars can be drilled into the initial support 2, and the steel frame 5 can be welded to the short steel bars for fixation.

[0048] The square timber 6 consists of long strips of wood with a rectangular cross-section, arranged longitudinally and multiple strips evenly distributed circumferentially. It can be secured to the inner side of the steel frame 5 using wire or similar binding methods. Made of wood, the square timber 6 is lightweight, does not impose a significant load on the overall structure, and possesses a certain degree of deformation capacity, allowing it to adapt to minor deformations in both the internal and external structures. It is low-cost and readily available.

[0049] Panel 7 can be made of bamboo plywood or wood panels, which can be slightly bent to form an arc panel. It is fixed to the inside of the square timber 6, and then spliced ​​circumferentially to form a ring before being spliced ​​longitudinally. Similarly, panel 7 is also relatively lightweight, will not place a large load on the overall structure, and can be further bent and deformed, making it highly adaptable. Its construction is also very convenient, as it can be directly fixed to the square timber 6 with nails, and the construction speed is extremely fast.

[0050] The integrated structure composed of the aforementioned steel frame 5, timber 6, and panel 7 can serve as the outer pouring formwork for the secondary lining 4, and can be used in conjunction with the concrete pouring trolley on the inner side of the tunnel (the concrete pouring trolley serves as the inner pouring formwork), forming a complete formwork system. From a functional perspective, the steel frame 5 acts as the main beam, the timber 6 as the secondary beam, and the panel 7 as the panel. The cross-sectional dimensions, spacing, thickness, and other parameters of the steel frame 5, timber 6, and panel 7 need to be calculated and determined considering the strength and stiffness requirements under concrete pouring loads.

[0051] The design of the air gap 3 in this invention creates an air interlayer between the initial support 2 and the secondary lining 4, providing thermal insulation. Therefore, the tunnel detached-wall thermal insulation lining structure of this invention can be used in high-temperature tunnel scenarios. In high-temperature tunnels, the surrounding rock 1 continuously transfers heat into the tunnel, worsening the construction and operating environment. The air gap 3 reduces heat transfer from the surrounding rock 1 into the tunnel, making it an effective measure to mitigate high-temperature heat hazards during tunnel construction and operation. Furthermore, the tunnel detached-wall thermal insulation lining structure of this invention can also be used in cold-region tunnel scenarios. In cold-region tunnels, cold air lowers the temperature of the secondary lining and the area behind it, causing the groundwater in the surrounding rock to freeze and expand, resulting in frost damage. The air gap 3 provides effective insulation.

[0052] In addition, the void layer 3 in this invention can also be used for the collection and discharge of seepage water from the surrounding rock. For example... Figure 4 In this embodiment, longitudinally arranged void layer drainage ditches 10 are provided at the bottom of both sides of the circumferential void layer 3. The void layer drainage ditches 10 are connected to the tunnel drainage ditch 11 through transversely arranged blind pipes 12. The void layer 3 serves as a drainage layer, naturally collecting groundwater that has seeped into the tunnel from the initial support 2, eliminating the need for traditional composite lining circumferential blind pipes, circumferential drainage boards, or circumferential waterproofing boards. The void layer drainage ditches 10 collect the infiltrated groundwater, which passes through the secondary lining 4 via the blind pipes 12 and is then introduced into the tunnel drainage ditch 11. In some embodiments, the blind pipes 12 may be made of pipes with anti-crystallization properties to reduce crystallization and blockage within the pipe. When the structure of this invention is used in cold-region tunnel scenarios, the void layer 3 has space to accommodate the volume expansion of groundwater upon freezing, which can reduce the frost heave pressure behind the secondary lining 4 and also reduce the destructive effects of freeze-thaw cycles. When the structure of the present invention is used in a high-temperature tunnel scenario, the high-temperature hot water penetrates the initial support 2 into the tunnel, avoiding the soaking of the secondary lining 4 by the high-temperature hot water, thereby further avoiding the risk of the high-temperature hot water penetrating the weak points, construction joints or deformation joints of the secondary lining 4, and preventing the occurrence of hot water leakage defects in the arch wall area inside the tunnel.

[0053] Generally, the waterproofing system of a detached lining structure consists of multiple layers of waterproofing. The secondary lining 4 has a certain self-waterproofing function, and waterstops and caulking are installed at the construction joints and expansion joints of the secondary lining 4. This is already a two-layer waterproofing system used in traditional technology. In this invention, a waterproofing membrane 9 is laid on the outside of the secondary lining 4, forming a new layer of waterproofing. From the outside (surrounding rock) to the inside (tunnel), the geotextile 8 and the waterproofing membrane 9 are sequentially fixed to the panel 7. Specifically, the waterproofing membrane 9 is installed on the inner side of the panel 7, located on the outside of the secondary lining 4, and the geotextile 8 is placed between the panel 7 and the waterproofing membrane 9. It should be noted that the geotextile 8 is an optional structure and can be omitted in some embodiments.

[0054] The construction method for the above-mentioned tunnel detached thermal insulation lining structure specifically includes the following steps:

[0055] S1: Excavate a tunnel in the surrounding rock 1.

[0056] S2: Initial support during construction 2.

[0057] S3: Create a longitudinal void layer water ditch 10 on the inner side of the bottom of both sides of the initial support 2, and pre-install a transverse blind pipe 12.

[0058] like Figure 4 The cross-section of the empty layer water ditch 10 is L-shaped, with a bottom plate and an inner vertical plate, and the initial support 2 serves as its outer vertical plate. It can be constructed by formwork casting.

[0059] S4: Fix a circumferentially arched steel frame 5 inside the initial support 2, with multiple steel frames 5 evenly arranged longitudinally.

[0060] When the inner wall of the initial support 2 is not smooth enough, the steel frame 5 cannot be tightly attached to the inner wall of the initial support 2. Short steel bars can be fixed by drilling holes on the surface of the initial support 2 and the steel frame 5 can be welded and fixed to the short steel bars.

[0061] S5: Longitudinal square timbers 6 are tied inside the steel frame 5, and multiple square timbers 6 are evenly arranged in a circumferential direction.

[0062] S6: Fix panel 7 inside the square timber 6. Multiple panels 7 are spliced ​​together in a ring and then spliced ​​together in a longitudinal direction to wrap the void layer drainage ditch 10 between panel 7 and initial support 2.

[0063] S7: The integral structure composed of steel frame 5, square timber 6 and panel 7 is used as the outer pouring template for secondary lining 4. A tunnel concrete pouring trolley is erected as the inner pouring template for secondary lining 4. Concrete is poured to construct secondary lining 4. During the pouring of secondary lining 4, a section of blind pipe 12 is embedded in it.

[0064] In the above method, a waterproof board 9 can also be laid. Specifically, a waterproof board 9 is laid on the inner surface of the panel 7, and the overall structure composed of the steel frame 5, square timber 6, panel 7 and waterproof board 9 is used as the outer pouring template for the secondary lining 4.

[0065] In the above method, geotextile 8 can also be laid, and geotextile 8 can be fixed to the inner surface of panel 7 by nails. Waterproof membrane 9 is fixed to the inner surface of geotextile 8. Specifically, the nails have plastic washers, and waterproof membrane 9 is welded to the plastic washers by a hot melt welding process, thereby fixing it to the inner side of panel 7.

[0066] Finally, a tunnel drainage ditch 11 is constructed inside the tunnel, and a pre-installed blind pipe 12 is connected to the tunnel drainage ditch 11.

[0067] Traditional open-plan structures require personnel to enter and erect formwork, i.e., the outer formwork for secondary lining. Therefore, a minimum width of approximately 50cm is necessary for personnel movement and work. In the open-plan structure of this invention, the integrated structure composed of steel frame 5, square timber 6, and panels 7 can directly serve as the outer formwork for secondary lining 4. Unlike traditional construction methods that require personnel to enter and erect formwork, this open-plan structure eliminates the need for personnel entry. Therefore, this invention's open-plan structure serves the dual purpose of heat insulation and acting as the outer formwork for concrete pouring.

[0068] Furthermore, this invention utilizes smaller-sized steel frames 5 and timber 6, significantly reducing the thickness of the void layer. This saves space and greatly increases the internal clearance of the tunnel. It also reduces the area of ​​the tunnel excavation cross-section, decreasing the amount of excavation work. The thickness of the void layer in this invention is equal to the sum of the thicknesses of the steel frame 5 and the timber 6. Due to the use of surface drilling to fix short reinforcing bars in the initial support 2, and welding the steel frame 5 to the short reinforcing bars, the load-bearing capacity of the steel frame 5 is significantly enhanced. Therefore, steel with smaller cross-sectional dimensions (compared to traditional tunnel steel frames) can be used to meet both load-bearing capacity and construction safety requirements. For ease of construction, steel frames 5 with a cross-sectional height of approximately 5cm and timber 6 with a cross-sectional height of approximately 10cm are feasible. Therefore, the void layer thickness of this invention can be controlled to approximately 15cm.

[0069] The above examples illustrate the present invention only to aid in understanding it and are not intended to limit the scope of the invention. Those skilled in the art can make various simple deductions, modifications, or substitutions based on the ideas of this invention.

Claims

1. A construction method for a tunnel detached-wall thermal insulation lining structure, characterized in that: The tunnel detached heat insulation lining structure includes an initial support (2) and a secondary lining (4) from the outside to the inside. There is a gap between the initial support (2) and the secondary lining (4) to form a void layer (3). The air gap (3) includes, from the outside to the inside, a steel frame (5), square timber (6) and a panel (7); the steel frame (5) is a circumferential arch frame, with multiple frames evenly arranged longitudinally and fixed to the inside of the initial support (2); the square timber (6) is arranged longitudinally, with multiple frames evenly arranged circumferentially and fixed to the inside of the steel frame (5); the panel (7) is an arc panel, which is spliced ​​circumferentially into a ring and then spliced ​​longitudinally and fixed to the inside of the square timber (6); The steel frame (5), the square timber (6), and the panel (7) constitute the outer casting template of the secondary lining (4); The method for constructing the tunnel detached thermal insulation lining structure includes: Excavating a tunnel; Initial construction support (2); In the initial support (2), a longitudinal empty layer water ditch (10) is made on the inner side of the bottom of both sides of the ring, and a transverse blind pipe (12) is pre-set. A circumferentially arched steel frame (5) is fixed inside the initial support (2), and multiple steel frames (5) are evenly arranged longitudinally. Longitudinal square timbers (6) are tied to the inside of the steel frame (5), and multiple square timbers (6) are evenly arranged in the circumference; Fix the panel (7) inside the square timber (6), and then splice multiple panels (7) together in a ring and then splice them together in a longitudinal direction to wrap the empty layer water ditch (10) between the panel (7) and the initial support (2); The integral structure composed of steel frame (5), square timber (6) and panel (7) is used as the outer pouring template of the secondary lining (4). A tunnel concrete pouring trolley is erected as the inner pouring template of the secondary lining (4) and concrete is poured to construct the secondary lining (4).

2. The construction method of the tunnel wall-separated thermal insulation lining structure according to claim 1, characterized in that: The method further includes: Waterproof board (9) is laid on the inner surface of panel (7), and the overall structure composed of steel frame (5), square timber (6), panel (7) and waterproof board (9) is used as the outer pouring template of secondary lining (4).

3. The construction method of the tunnel wall-separated thermal insulation lining structure according to claim 2, characterized in that: The method further includes: Geotextile (8) is fixed to the inner surface of panel (7) by nailing, and waterproof board (9) is fixed to the inner surface of geotextile (8).

4. The construction method of the tunnel wall-separated thermal insulation lining structure according to claim 3, characterized in that: The method further includes: The nail has a plastic washer, and the waterproof plate (9) is welded to the plastic washer by a hot melt welding process, thereby fixing it to the inside of the panel (7).

5. The construction method of the tunnel wall-separated thermal insulation lining structure according to claim 4, characterized in that: The method further includes: A tunnel drainage ditch (11) is constructed inside the tunnel, and a pre-installed blind pipe (12) is connected to the tunnel drainage ditch (11).

6. The construction method of the tunnel detached-wall thermal insulation lining structure according to claim 5, characterized in that: The inner side of the initial support (2) is provided with exposed short steel bars, and the steel frame (5) is fixed to the short steel bars.

7. The construction method of the tunnel detached-wall thermal insulation lining structure according to claim 6, characterized in that: The bottom of the circumferential sides of the detached layer (3) is provided with longitudinally arranged detached layer water ditches (10), and the detached layer water ditches (10) are connected to the water ditch (11) in the tunnel through a horizontally arranged blind pipe (12).

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