Composite gradient lining structure for highway tunnel in cold region

Abstract

The utility model discloses a composite gradient lining structure for a highway tunnel in a cold region, which relates to the technical field of tunnel construction and comprises a tunnel primary support serving as an outermost support structure, a tunnel inverted arch arranged at the bottom of the tunnel and connected with the tunnel primary support, and a tunnel filling layer arranged above the tunnel inverted arch. Through optimal combination of different materials, a gradient transition layer is formed, material stress concentration caused by freeze-thaw cycle is effectively relieved, lining cracking and peeling risks are remarkably reduced, and the service life of a tunnel in a low-temperature environment is prolonged; according to the design of the tunnel composite gradient lining structure in the scheme, the thickness can be adjusted according to the grade of surrounding rock when a new project is applied, but due to the excellent performance of materials used by the composite gradient lining, the total thickness of the lining structure is smaller than that of a common structure, the excavation volume of the surrounding rock can be reduced, the construction risk is integrally reduced, and the engineering economy is improved.

Description

Technical Field

[0001] This utility model relates to the field of tunnel construction technology, specifically to a composite gradient lining structure for highway tunnels in cold regions. Background Technology

[0002] As the main load-bearing structure of a tunnel, the tunnel lining plays a crucial role in resisting rock pressure, controlling rock deformation, and maintaining traffic safety. Therefore, the safety and stability of the tunnel lining structure is a core issue that needs to be addressed in highway tunnels. According to relevant literature, cracking in highway tunnel linings is a relatively common problem in my country. The causes of cracks are generally complex, and factors such as design, construction, maintenance, deterioration of surrounding rock and materials, and disasters like earthquakes can all lead to the generation and development of cracks. Cracks weaken the tunnel's structural load-bearing system, reduce structural durability, and cause secondary problems such as structural deformation and water leakage. In severe cases, they can even induce sudden rockfalls, posing a serious threat to public safety.

[0003] In recent years, the tunnel engineering industry has focused on improvements in various aspects, including surveying and design schemes, construction management, construction quality, and maintenance measures. While the persistent problem of tunnel lining cracking has been significantly mitigated, it remains unresolved. The core issue lies in the fact that traditional (reinforced) concrete lining structures, while possessing inherent advantages, inevitably suffer from drawbacks such as high material brittleness, low ultimate tensile strain, and susceptibility to cracking. Therefore, innovative composite structures based on material innovation offer a promising solution. This paper proposes a novel composite gradient tunnel lining structure. This structure meets the strength and stiffness requirements of relevant industry tunnel specifications while exhibiting good toughness. The overall structure combines rigidity and flexibility, achieving the goal of crack resistance and toughening of the tunnel lining, thereby reducing operational safety hazards. Therefore, based on the above research and existing technologies, a composite gradient lining structure for highway tunnels in cold regions is proposed to address the aforementioned problems. Utility Model Content

[0004] The purpose of this invention is to provide a composite gradient lining structure for highway tunnels in cold regions, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] A composite gradient lining structure for highway tunnels in cold regions includes: an initial tunnel support, which serves as the outermost support structure; a tunnel invert at the bottom of the tunnel, which is connected to the initial tunnel support; a tunnel filling layer above the tunnel invert; and a composite gradient lining shotcrete with steel fiber reinforced concrete on the inner side of the initial tunnel support, wherein the thickness of the composite gradient lining shotcrete with steel fiber reinforced concrete is 1 / 2 of the total thickness h of the lining structure.

[0007] A composite gradient lining high-toughness concrete material is poured inside the composite gradient lining sprayed steel fiber concrete, and the thickness of the material poured inside the composite gradient lining sprayed steel fiber concrete is 1 / 2 of the total thickness h of the lining structure.

[0008] The outer edge steel mesh is set before the construction of the composite gradient lining shotcrete, with a mesh spacing of 25cm×25cm. The outer edge steel mesh is fixed to the inner side of the tunnel initial support.

[0009] The composite gradient lining connecting shear bars are embedded in the composite gradient lining sprayed steel fiber concrete, with a longitudinal and circumferential spacing of 50cm×50cm, arranged in a quincunx pattern, and one end of the composite gradient lining connecting shear bars is connected to the outer edge steel mesh.

[0010] The inner edge steel mesh is tied before the pouring of the high-toughness concrete material of the composite gradient lining, and the inner edge steel mesh is reliably connected to the L-shaped bend of the connecting shear reinforcement of the composite gradient lining.

[0011] Furthermore, the interface between the composite gradient lining shotcrete and the composite gradient lining high-toughness concrete material is roughened before final setting, with a difference in unevenness of not less than 6mm.

[0012] Furthermore, the initial support of the tunnel is equipped with a monitoring mechanism, which includes: a joint gauge, a surface strain gauge, a laser displacement gauge, a multi-sensor data acquisition instrument, and a thermometer and hygrometer. The joint gauge is set with 9 measuring points on each monitoring section to monitor the interface connection effect. The surface strain gauge is set with 5 measuring points on each monitoring section to measure the strain of the lining surface. The laser displacement gauge is set on both sides of the arch waist to monitor the horizontal convergence of the lining structure. The thermometer and hygrometer are set on the lining sidewalls to monitor the temperature and humidity of the lining wall.

[0013] Furthermore, the joint gauge is placed between the composite gradient lining sprayed steel fiber concrete and the composite gradient lining high-toughness concrete material.

[0014] Furthermore, the toughness index of the composite gradient lining high-toughness concrete material meets the requirements for crack resistance and toughening of tunnel lining, and its ultimate tensile strain is greater than that of traditional concrete materials, effectively reducing the risk of lining cracking.

[0015] Furthermore, the total thickness h of the lining structure can be adjusted according to the surrounding rock grade, but through the optimized combination of composite gradient materials, its total thickness is less than that of the traditional lining structure, thus reducing the amount of surrounding rock excavation.

[0016] Compared with the prior art, the beneficial effects of this utility model are:

[0017] 1. The design of the composite gradient lining structure for the tunnel in this scheme forms a gradient transition layer through the optimized combination of different materials, which effectively alleviates the stress concentration of materials caused by freeze-thaw cycles, significantly reduces the risk of lining cracking and spalling, and extends the service life of the tunnel in low-temperature environments.

[0018] The design of the composite gradient lining structure for tunnels in this scheme allows for thickness adjustment based on the surrounding rock grade when applied in new projects. However, due to the excellent performance of the materials used in the composite gradient lining, the total thickness of the lining structure is less than that of ordinary structures. Therefore, it can reduce the amount of surrounding rock excavation, reduce overall construction risks and improve project economy, while also reducing later maintenance investment.

[0019] Monitoring agencies can dynamically collect key parameters such as temperature, stress, and strain of the lining structure. Through data analysis, they can identify potential defects in advance, provide a scientific basis for maintenance decisions, and reduce the safety risks caused by sudden structural failures. By combining big data analysis, monitoring agencies can predict long-term performance changes of the lining structure, optimize maintenance strategies, reduce resource waste, and conform to the development trend of green transportation infrastructure. Attached Figure Description

[0020] Figure 1 This is a cross-sectional view of the tunnel composite gradient lining structure of this utility model;

[0021] Figure 2 This is a schematic diagram showing the arrangement of the shear reinforcement in the composite gradient lining of this utility model.

[0022] Figure 3 This is a schematic diagram of the logical operation of the monitoring mechanism of this utility model;

[0023] Figure 4 This is a schematic diagram showing the arrangement of the data sensing sensors of this utility model.

[0024] In the figure: 1. Initial support of the tunnel; 2. Tunnel invert; 3. Tunnel filling layer; 4. Composite gradient lining shotcrete with steel fiber reinforced concrete; 5. Composite gradient lining high-toughness concrete material; 6. Composite gradient lining connecting shear reinforcement; 7. Inner edge steel mesh; 8. Outer edge steel mesh; 9. Joint gauge; 10. Surface strain gauge; 11. Laser displacement gauge; 12. Thermohygrometer; 13. Multi-element sensor data acquisition instrument. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0026] In one typical implementation of this application, please refer to Figures 1-4 A composite gradient lining structure for highway tunnels in cold regions includes an initial tunnel support 1, which serves as the outermost support structure and is constructed using shotcrete technology.

[0027] A tunnel invert 2 is set at the bottom of the tunnel. The tunnel invert 2 is connected to the tunnel initial support 1 to form a closed support ring. A tunnel filling layer 3 is set above the tunnel invert 2. It is made of C15 plain concrete. A composite gradient lining shotcrete 4 is set on the inner side of the tunnel initial support 1. The thickness of the composite gradient lining shotcrete 4 is 1 / 2 of the total thickness h of the lining structure.

[0028] The composite gradient lining high-toughness concrete material 5 is poured inside the composite gradient lining sprayed steel fiber concrete 4, and the thickness of the composite gradient lining sprayed steel fiber concrete 4 inside the composite gradient lining is 1 / 2 of the total thickness h of the lining structure.

[0029] The outer edge steel mesh 8 is set before the construction of the composite gradient lining shotcrete 4. The mesh spacing is 25cm×25cm. The outer edge steel mesh 8 is fixed to the inner side of the tunnel initial support 1.

[0030] The composite gradient lining connecting shear reinforcement 6 is embedded in the composite gradient lining sprayed steel fiber concrete 4, with a longitudinal and circumferential spacing of 50cm×50cm, arranged in a quincunx pattern. One end of the composite gradient lining connecting shear reinforcement 6 is connected to the outer edge steel mesh 8.

[0031] The inner edge steel mesh 7 is tied before the pouring of the high-toughness concrete material 5 of the composite gradient lining. The inner edge steel mesh 7 is reliably connected to the L-shaped bend of the shear reinforcement 6 of the composite gradient lining.

[0032] In this method, the initial support 1, tunnel invert arch 2, and tunnel filling layer 3 work together to form a complete initial support system. Composite gradient lining shotcrete 4 provides high-strength support, composite gradient lining high-toughness concrete material 5 enhances crack resistance, and composite gradient lining connecting shear reinforcement 6, inner edge steel mesh 7, and outer edge steel mesh 8 form a spatial stress skeleton, realizing a composite structure that combines rigidity and flexibility, and effectively dispersing stress concentration.

[0033] The interface between the composite gradient lining shotcrete steel fiber concrete 4 and the composite gradient lining high-toughness concrete material 5 is roughened before final setting, with a difference in unevenness of not less than 6mm, in order to enhance the bonding performance of the two layers of materials.

[0034] The composite gradient lining shotcrete 4 and the composite gradient lining high-toughness concrete material 5 are mechanically interlocked through a roughening process, which enhances the interfacial bonding performance and prevents peeling damage between the composite gradient lining shotcrete 4 and the composite gradient lining high-toughness concrete material 5.

[0035] The initial support of the tunnel 1 is equipped with a monitoring mechanism, which includes: a joint gauge 9, a surface strain gauge 10, a laser displacement gauge 11, a multi-element sensor data acquisition instrument 13, and a thermometer and hygrometer 12. The joint gauge 9 is equipped with 9 measuring points on each monitoring section, located at the arch feet 9-1, 9-2, arch rise line 9-3, 9-4, arch waist 9-5, 9-6, arch shoulder 9-7, 9-8, and arch crown 9-9, respectively, to monitor the interface connection effect.

[0036] Five measuring points are set up on each monitoring section of the surface strain gauge 10, located at the arching line 10-1, 10-2, arch waist upwards 10-3, 10-4 and arch top 10-5, respectively, to measure the strain of the lining surface;

[0037] Laser displacement gauges 11 are installed on the two sides of the arch waist 11-1 and 11-2 to monitor the horizontal convergence of the lining structure. Temperature and humidity gauges 12 are installed on the side walls of the lining to monitor the temperature and humidity of the lining wall surface.

[0038] The monitoring agency also includes a data acquisition layer, a data transmission layer, and a platform analysis layer;

[0039] The data acquisition layer employs a multi-sensor data acquisition instrument 13 for remote monitoring and real-time safety early warning. This universal multi-sensor data acquisition instrument, suitable for various engineering safety monitoring projects, enables remote monitoring and real-time safety early warning within tunnels, and completes automatic measurement and data recording of engineering safety monitoring sensors. It can acquire, parse, and process various interface standards, compatible protocols, and data standards, achieving standardization of sensor data and facilitating data storage and application. This effectively solves the problem of different types of sensors requiring different data acquisition devices. Utilizing multiple communication technologies such as 5G, Bluetooth, and Ethernet, it enables multiple ways of uploading sensor data, adapting to various field application scenarios and reducing the risk of network interruptions leading to operational failures and data loss. This ensures the applicability, security, flexibility, and reliability of the data acquisition system. The data acquisition layer also includes corresponding power supplies, chassis, cables, and other equipment for the monitoring devices.

[0040] Platform analysis layer: It consists of cloud servers, data acquisition and analysis software, and a database that supports big data storage. The data acquisition and analysis software is responsible for sending data acquisition commands to the front-end acquisition system and receiving and sending data back from the front-end acquisition system. After processing the received data, it writes it into the database and performs real-time analysis of the received data based on mathematical models, and issues alarms for abnormal data.

[0041] Data transmission layer: Wireless communication technology is used to transmit the collected data back to the data center. The core component of the network transmission system is the wireless transceiver module, which is compatible with the 5G networks of the three major operators. It has a fast transmission rate and ensures real-time data transmission.

[0042] The crack gauge 9 monitors interface cracking, the surface strain gauge 10 measures surface strain, the laser displacement gauge 11 monitors convergence deformation, the thermometer and hygrometer 12 detects environmental parameters, and the multi-sensor data acquisition instrument 13 integrates and analyzes the data. Through multi-parameter, all-round real-time monitoring, it accurately captures the stress, deformation and environmental changes of the lining structure, and combined with intelligent analysis, it provides early warning of potential defects, providing data support for scientific maintenance and significantly improving the safety of tunnel operation.

[0043] Before the composite gradient lining high-toughness concrete material 5 is poured, the joint gauge 9 is slightly removed from the sprayed concrete layer according to the installation position, and the joint gauge 9 is placed between the composite gradient lining sprayed steel fiber concrete 4 and the composite gradient lining high-toughness concrete material 5.

[0044] The joint gauge 9 directly monitors the interface connection status between the composite gradient lining shotcrete 4 and the composite gradient lining high-toughness concrete material 5, and promptly detects the risk of interface separation, providing a basis for targeted maintenance.

[0045] The toughness index of the composite gradient lining high-toughness concrete material 5 meets the requirements for crack resistance and toughening of tunnel lining. Its ultimate tensile strain is greater than that of traditional concrete materials, which effectively reduces the risk of lining cracking.

[0046] The total thickness h of the lining structure can be adjusted according to the surrounding rock grade. However, through the optimized combination of composite gradient materials, its total thickness is less than that of the traditional lining structure, reducing the amount of surrounding rock excavation. The optimization of material properties allows the lining thickness to be reduced, thereby reducing excavation costs and construction difficulty, while also reducing the amount of concrete used, achieving a dual improvement in economic benefits and structural performance.

[0047] As a preferred embodiment of this example, please refer to [link / reference]. Figures 1-4 The specific construction method is as follows:

[0048] Step 1: The tunnel composite gradient lining structure consists of composite gradient lining shotcrete steel fiber concrete 4, composite gradient lining high toughness concrete material 5, composite gradient lining connecting shear reinforcement 6, inner edge steel mesh 7, and outer edge steel mesh 8.

[0049] Step 2: The composite gradient lining structure of the tunnel is implemented after the initial support 1, tunnel invert 2, tunnel filling layer 3, and waterproof layer are completed. The total thickness of the structure is h, of which the composite gradient lining shotcrete 4, constructed first, has a thickness of h / 2, and the composite gradient lining high-toughness concrete material 5, constructed later, has a thickness of h / 2.

[0050] Step 3: Before the application of shotcrete 4, install an outer edge steel mesh 8 with a mesh spacing of 25cm×25cm. To enhance the connection performance of the composite gradient lining structure constructed sequentially, pre-embed composite gradient lining connecting shear bars 6 with a longitudinal and circumferential spacing of 50cm×50cm in a staggered pattern.

[0051] Step 4: Before the final setting time of the sprayed steel fiber concrete 4, roughen the interface to a minimum unevenness of 6mm, and tie the inner edge steel mesh 7. The L-shaped bends of the composite gradient lining connecting shear bars 6 should be reliably connected to the outer edge steel bars. Use a tunnel lining concrete trolley to pour the composite gradient lining high-toughness concrete material 5, and remove the formwork after it reaches the design strength.

[0052] The above are merely preferred embodiments of this utility model, but the scope of protection of this utility model is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in this utility model, based on the technical solution and inventive concept of this utility model, should be included within the scope of protection of this utility model.

Claims

1. A composite gradient lining structure for highway tunnels in cold regions, characterized in that, include: The tunnel initial support (1) serves as the outermost support structure. A tunnel invert (2) is provided at the bottom of the tunnel. The tunnel invert (2) is connected to the tunnel initial support (1). A tunnel filling layer (3) is provided above the tunnel invert (2). A composite gradient lining shotcrete (4) is provided on the inner side of the tunnel initial support (1). The thickness of the composite gradient lining shotcrete (4) is 1 / 2 of the total thickness h of the lining structure. Composite gradient lining high toughness concrete material (5), the composite gradient lining high toughness concrete material (5) is poured on the inner side of composite gradient lining sprayed steel fiber concrete (4), the thickness of the composite gradient lining sprayed steel fiber concrete (4) is 1 / 2 of the total thickness h of the lining structure. The outer edge steel mesh (8) is set before the construction of the composite gradient lining shotcrete (4) with a mesh spacing of 25cm×25cm. The outer edge steel mesh (8) is fixed to the inner side of the tunnel initial support (1). Composite gradient lining connecting shear reinforcement (6) is embedded in the composite gradient lining sprayed steel fiber concrete (4), with a longitudinal and circumferential spacing of 50cm×50cm and a quincunx arrangement. One end of the composite gradient lining connecting shear reinforcement (6) is connected to the outer edge steel mesh (8). The inner edge steel mesh (7) is tied before the pouring of the composite gradient lining high-toughness concrete material (5), and the inner edge steel mesh (7) is reliably connected to the L-shaped bend of the composite gradient lining connecting shear bar (6).

2. The composite gradient lining structure for highway tunnels in cold regions according to claim 1, characterized in that: The interface between the composite gradient lining shotcrete (4) and the composite gradient lining high-toughness concrete material (5) is roughened before final setting, with a difference in unevenness of not less than 6 mm.

3. A composite gradient lining structure for highway tunnels in cold regions according to claim 2, characterized in that: The initial support (1) of the tunnel is equipped with a monitoring mechanism, which includes: a joint gauge (9), a surface strain gauge (10), a laser displacement gauge (11), a multi-sensor data acquisition instrument (13), and a thermometer and hygrometer (12). The joint gauge (9) is set up with 9 measuring points on each monitoring section to monitor the interface connection effect. The surface strain gauge (10) is set up with 5 measuring points on each monitoring section to measure the strain of the lining surface. The laser displacement gauge (11) is set up on both sides of the arch waist to monitor the horizontal convergence of the lining structure. The thermometer and hygrometer (12) is set up on the lining sidewall to monitor the temperature and humidity of the lining wall.

4. A composite gradient lining structure for highway tunnels in cold regions according to claim 3, characterized in that: The joint gauge (9) is placed between the composite gradient lining sprayed steel fiber concrete (4) and the composite gradient lining high toughness concrete material (5).

5. A composite gradient lining structure for highway tunnels in cold regions according to claim 2, characterized in that: The toughness index of the composite gradient lining high-toughness concrete material (5) meets the requirements for crack resistance and toughening of tunnel lining, and its ultimate tensile strain is greater than that of traditional concrete materials.

6. A composite gradient lining structure for highway tunnels in cold regions according to claim 5, characterized in that: The total thickness h of the lining structure can be adjusted according to the surrounding rock grade, but through the optimized combination of composite gradient materials, its total thickness is less than that of the traditional lining structure, thus reducing the amount of surrounding rock excavation.

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