Tunnel seismic structure based on composite lining and gradient grouting and construction method thereof

Abstract

The application discloses a tunnel anti-seismic structure based on gradient grouting and composite lining and a construction method thereof, and the construction method comprises the following steps: detecting the surrounding rock geology, identifying the distribution of weak areas, hollow areas and stable areas of the surrounding rock, dividing the surrounding rock into high-risk areas, medium-risk areas and low-risk areas according to the detection results, and adopting different grouting modes, different grout proportions, different grouting parameters and different grouting thicknesses to perform gradient grading grouting reinforcement on the risk areas; pouring a flexible layer based on the inner side of the grouting reinforced surrounding rock, installing an energy consumption interlayer in the inner side of the flexible layer, and pouring and manufacturing a high-strength rigid layer in the inner side of the energy consumption interlayer; and setting a monitoring and intelligent alarm system in the lining for real-time monitoring of the deformation and displacement data of the internal structure of the tunnel. Through the triple protection of rigid compression-energy consumption buffer-flexible energy release, the application improves the seismic energy dissipation rate, and the surrounding rock grading grouting reduces material waste, so that the matching degree of the surrounding rock-lining rigidity is significantly improved.

Description

Technical Field

[0001] This invention relates to the field of tunnel engineering construction technology, specifically to a tunnel seismic-resistant structure based on composite lining and gradient grouting and its construction method. Background Technology

[0002] In recent years, the damage to underground structures during earthquakes has highlighted the importance of earthquake resistance in underground structures.

[0003] Traditional tunnel seismic design primarily employs two methods: structural reinforcement and surrounding rock strengthening. However, existing single-method tunnel seismic resistance techniques have significant limitations. Regarding structural reinforcement, early methods commonly increased stiffness by adding lining thickness and full-section reinforcement. However, research shows that while excessive stiffness can reduce axial stress, it also leads to an increase in shear and bending stress. Furthermore, rigid structures are unable to effectively dissipate seismic energy and may even exacerbate dynamic response. In recent years, the concept of flexible structures has gained increasing attention, but if stiffness is too low, it may cause excessive displacement, affecting tunnel stability. As for surrounding rock strengthening, grouting is commonly used. While conventional grouting techniques (such as full-section grouting and intermittent grouting) can improve the mechanical properties of the surrounding rock, they lack precise control for different geological conditions (such as weak zones and fractured rock masses), resulting in insufficient stiffness matching between the surrounding rock and the lining. Especially under seismic loading, stiffness differences easily lead to interface stress concentration, accelerating lining cracking. In addition, existing grouting processes do not fully consider the correlation between seismic wave frequency bands and the dynamic characteristics of surrounding rock, and the selection of reinforcement range and thickness lacks theoretical support; the limited availability of materials also restricts the improvement of seismic performance, such as the brittle failure problem of traditional reinforced concrete under high-frequency vibration.

[0004] In summary, current tunnel seismic resistance technology faces core problems such as structural rigidity-flexibility imbalance, insufficient targeted reinforcement of surrounding rock, and lack of synergistic optimization of material properties. A systematic solution is urgently needed to achieve efficient energy dissipation and stress redistribution under seismic loads. Summary of the Invention

[0005] In response to the problems mentioned in the background technology of existing tunnel seismic resistance technology, such as structural rigidity-flexibility imbalance, insufficient targeted surrounding rock reinforcement, and lack of synergistic optimization of material properties, this invention provides a tunnel seismic resistance structure and its construction method based on composite lining and gradient grouting. The aim is to achieve efficient energy dissipation and stress redistribution of tunnels under seismic loads, while optimizing the surrounding rock grouting reinforcement method and saving construction costs.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] The construction method for seismic-resistant tunnel structures based on gradient grouting and composite lining includes the following steps:

[0008] S1. Graded grouting reinforcement of surrounding rock, specifically including: geological exploration of the surrounding rock to identify the distribution of weak areas, cavities, and stable areas; based on the exploration results and combined with experience and existing theories, dividing the surrounding rock into high-risk areas, medium-risk areas, and low-risk areas; and graded grouting reinforcement of the surrounding rock using different grouting methods, different paste-grout ratios, different grouting parameters, and different grouting thicknesses for the high-risk areas, medium-risk areas, and low-risk areas.

[0009] S2. Composite lining construction based on grouting-reinforced surrounding rock, specifically including: pouring a flexible layer inside the surrounding rock, the flexible layer being used to absorb shear stress and bending stress, the flexible layer being made of rubber particle modified polymer concrete or carbon fiber reinforced elastic concrete; installing and fixing an energy-dissipating interlayer inside the flexible layer, the energy-dissipating interlayer being made of damping alloy mesh or shape memory polymer material; pouring and constructing a high-strength rigid layer inside the energy-dissipating interlayer, the high-strength rigid layer being completed by steel fiber reinforced concrete formwork grouting.

[0010] S3. A monitoring and intelligent alarm system is installed inside the lining. The monitoring and intelligent alarm system monitors the deformation and displacement data of the tunnel in real time. When the monitoring data reaches a set threshold, the alarm system is intelligently activated.

[0011] Furthermore, the high-risk area adopts the full-section grouting method, the medium-risk area adopts the interval grouting method, and the low-risk area adopts the local reinforcement grouting method.

[0012] Preferably, the high-risk area is grouted with fast-setting ultrafine cement grout, with an initial setting time ≤30 minutes, a grouting pressure ≥2MPa, and a grout filling rate ≥95%; the medium-risk area is grouted with slow-setting bentonite-cement mixture, with an initial setting time of 2-4 hours and a grouting pressure of 1-1.5MPa; the low-risk area is grouted with nano-silicate grouting agent for localized jet grouting, with a grouting pressure ≤0.5MPa, and only the surface of the surrounding rock is reinforced.

[0013] Preferably, the grouting thickness of the high-risk zone, medium-risk zone, and low-risk zone is determined by the following formula:

[0014] T = K·ln(Er / Es);

[0015] In the formula, T is the grouting thickness, Er is the initial deformation modulus of the surrounding rock, Es is the target modulus, and K is the correction coefficient.

[0016] Preferably, the elastic modulus of the flexible layer is 1 / 5 to 1 / 3 of the elastic modulus of the high-strength rigid layer.

[0017] Preferably, when pouring the high-strength rigid layer, the grouting pressure and flow rate are intelligently adjusted in real time using a PID algorithm to match the deformation requirements of the surrounding rock.

[0018] Preferably, the monitoring and intelligent alarm system installed inside the lining includes: an earth pressure cell installed at the interface between the surrounding flexible layer and the lining to monitor the contact pressure at the interface between the surrounding rock and the flexible layer in real time; a displacement meter installed at the interface between the energy dissipation interlayer and the high-strength rigid layer to monitor the relative displacement at the interface between the energy dissipation interlayer and the high-strength rigid layer in real time; and a fiber optic grating sensor and a piezoelectric accelerometer installed in the flexible layer, wherein the fiber optic grating sensor is used to monitor stress changes and cracks in the flexible layer, and the piezoelectric accelerometer is used to record the dynamic response of the flexible layer in real time.

[0019] Furthermore, this invention proposes a tunnel seismic-resistant structure based on gradient grouting and composite lining, comprising: a composite lining provided on the inner side of the tunnel surrounding rock, the composite lining comprising a flexible layer, an energy-dissipating interlayer, and a high-strength rigid layer, wherein the flexible layer is provided on the inner side of the surrounding rock, the energy-dissipating interlayer is provided on the inner side of the flexible layer, and the high-strength rigid layer is provided on the inner side of the energy-dissipating interlayer; the flexible layer is cast using rubber particle modified polymer concrete or carbon fiber reinforced elastic concrete; the energy-dissipating interlayer is made of damping alloy mesh or shape memory polymer material; the energy-dissipating interlayer is fixedly connected to the flexible layer by anchoring nails; and the high-strength rigid layer is cast using steel fiber reinforced concrete formwork grouting; a monitoring and intelligent alarm system is installed inside the lining for real-time monitoring of the deformation and displacement of the tunnel internal structure.

[0020] Preferably, the monitoring and intelligent alarm system includes an earth pressure cell disposed at the interface between the surrounding rock and the flexible layer, a displacement meter disposed at the interface between the energy dissipation interlayer and the high-strength rigid layer, a fiber Bragg grating sensor and a piezoelectric accelerometer disposed inside the flexible layer, and the intelligent alarm system is connected to the earth pressure cell, the displacement meter, the fiber Bragg grating sensor and the piezoelectric accelerometer respectively.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] This invention proposes a tunnel seismic-resistant structure and construction method based on composite lining and gradient grouting. Through gradient-graded grouting reinforcement of the surrounding rock, a three-layer composite lining structure consisting of a flexible layer, an energy-dissipating interlayer, and a high-strength rigid layer, along with monitoring sensors and an intelligent alarm system, the seismic performance of the tunnel is significantly improved. Specifically, the three-layer composite lining structure achieves triple protection—rigid compression resistance, energy dissipation buffering, and flexible energy release—achieving a dynamic balance between rigidity and flexibility in the lining and increasing the seismic energy dissipation rate. By dividing the surrounding rock into high-risk, medium-risk, and low-risk zones, reasonable gradient-graded grouting reduces material waste and significantly improves the stiffness matching between the surrounding rock and the lining. Attached Figure Description

[0023] Figure 1This is a schematic cross-sectional view of the tunnel seismic-resistant structure based on composite lining and gradient grouting according to the present invention.

[0024] Figure 2 This is a schematic diagram of the arrangement of monitoring sensors in the tunnel seismic-resistant structure based on composite lining and gradient grouting according to the present invention;

[0025] Figure 3 This is a flowchart of the construction method for a tunnel seismic-resistant structure based on composite lining and gradient grouting according to the present invention;

[0026] In the figure: 1. Surrounding rock; 2. Flexible layer; 3. Energy dissipation interlayer; 4. High-strength rigid layer; 5. Earth pressure cell; 6. Displacement gauge; 7. Fiber optic grating sensor; 8. Piezoelectric accelerometer. Detailed Implementation

[0027] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. Obviously, the embodiments described in this invention are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0028] In this specification, the terms “comprising,” “including,” “having,” and variations thereof mean “including, but not limited to,” unless otherwise specifically emphasized.

[0029] Reference Figures 1 to 2 This invention discloses a tunnel seismic-resistant structure based on gradient grouting and composite lining, comprising: a flexible layer disposed on the inner side of the tunnel surrounding rock; an energy-dissipating interlayer disposed on the inner side of the flexible layer; and a high-strength rigid layer disposed on the inner side of the energy-dissipating interlayer. The flexible layer is constructed using rubber particle-modified polymer concrete or carbon fiber reinforced elastic concrete. The energy-dissipating interlayer is constructed using damping alloy mesh or shape memory polymer material. The energy-dissipating interlayer is fixedly connected to the flexible layer by anchoring nails. The high-strength rigid layer is constructed using steel fiber reinforced concrete formwork and grouting. An earth pressure cell is disposed at the interface between the surrounding rock and the flexible layer, and a displacement meter is disposed at the interface between the energy-dissipating interlayer and the high-strength rigid layer. A fiber optic grating sensor and a piezoelectric accelerometer are disposed inside the flexible layer. The earth pressure cell, displacement meter, fiber optic grating sensor, and piezoelectric accelerometer are all connected to an intelligent alarm system.

[0030] Among them, the pressure cell is used to monitor the contact pressure at the interface between the surrounding rock and the flexible layer in real time, the displacement meter is used to monitor the relative displacement at the interface between the energy dissipation interlayer and the high-strength rigid layer in real time, the fiber optic grating sensor is used to monitor the stress changes and cracks in the flexible layer, and the piezoelectric accelerometer is used to record the dynamic response of the flexible layer in real time.

[0031] Reference Figure 3 The present invention relates to a construction method for a tunnel seismic-resistant structure based on gradient grouting and composite lining, comprising the following steps:

[0032] S1. Graded grouting reinforcement of surrounding rock, specifically including: geological exploration of the surrounding rock to identify the distribution of weak areas, cavities, and stable areas; based on the exploration results and combined with experience and existing theories, dividing the surrounding rock into high-risk areas, medium-risk areas, and low-risk areas; and graded grouting reinforcement of the surrounding rock using different grouting methods, different paste-grout ratios, different grouting parameters, and different grouting thicknesses for the high-risk areas, medium-risk areas, and low-risk areas.

[0033] S2. Composite lining construction based on grouting-reinforced surrounding rock, specifically including: pouring a flexible layer inside the surrounding rock to absorb shear and bending stress; the flexible layer is made of rubber particle modified polymer concrete or carbon fiber reinforced elastic concrete; installing and fixing an energy-dissipating interlayer inside the flexible layer; the energy-dissipating interlayer is made of damping alloy mesh or shape memory polymer material; and pouring a high-strength rigid layer inside the energy-dissipating interlayer, which is completed by grouting through steel fiber reinforced concrete formwork.

[0034] S3. A monitoring and intelligent alarm system is installed inside the lining. This system monitors the tunnel's deformation and displacement data in real time. When the monitored data reaches a set threshold, the alarm system is activated intelligently. Specifically, this includes installing earth pressure cells at the interface of the flexible layer, installing displacement gauges at the interface of the energy-dissipating interlayer and the high-strength rigid layer, and pre-embedding fiber optic grating sensors and piezoelectric accelerometers inside the flexible layer.

[0035] The high-risk area uses full-section grouting, the medium-risk area uses intermittent grouting, and the low-risk area uses local reinforcement grouting. In the high-risk area, rapid-setting ultrafine cement grout is used with an initial setting time ≤30 minutes, a grouting pressure ≥2 MPa, and a grout filling rate ≥95%. In the medium-risk area, a slow-setting bentonite-cement mixture is used with an initial setting time of 2–4 hours and a grouting pressure of 1–1.5 MPa. In the low-risk area, nano-silicate grouting agent is used for localized jet grouting with a grouting pressure ≤0.5 MPa, and only the surface of the surrounding rock is reinforced.

[0036] The grouting thickness in high-risk, medium-risk, and low-risk areas is determined by the formula T = K·ln(Er / Es), where T is the grouting thickness, Er is the initial deformation modulus of the surrounding rock, Es is the target modulus, and K is a correction coefficient. The elastic modulus of the flexible layer is 1 / 5 to 1 / 3 of that of the high-strength rigid layer.

[0037] When pouring the high-strength rigid layer, the grouting pressure and flow rate are intelligently adjusted in real time using a PID algorithm to match the deformation requirements of the surrounding rock.

[0038] It should be noted that the high-strength rigid layer in this invention can also be made by connecting precast reinforced concrete slabs, with each slab connected by high-strength bolts to ensure that the overall rigidity meets the seismic design requirements.

[0039] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A construction method for seismic-resistant tunnel structures based on gradient grouting and composite lining, characterized in that, Includes the following steps: S1. Gradient-graded grouting reinforcement of surrounding rock, specifically including: geological exploration of the surrounding rock to identify the distribution of weak, cavitary, and stable zones; based on the exploration results and combined with experience and existing theories, dividing the surrounding rock into high-risk, medium-risk, and low-risk zones; and using different grouting methods, different paste-grout ratios, different grouting parameters, and different grouting thicknesses to perform graded grouting reinforcement of the surrounding rock in the high-risk, medium-risk, and low-risk zones. S2. Composite lining construction based on grouting-reinforced surrounding rock, specifically including: pouring a flexible layer inside the surrounding rock, the flexible layer being used to absorb shear stress and bending stress, the flexible layer being poured using rubber particle modified polymer concrete or carbon fiber reinforced elastic concrete; installing and fixing an energy-dissipating interlayer inside the flexible layer, the energy-dissipating interlayer being made of damping alloy mesh or shape memory polymer material; pouring a high-strength rigid layer inside the energy-dissipating interlayer, the high-strength rigid layer being poured using steel fiber reinforced concrete formwork and grouting. S3. A monitoring and intelligent alarm system is installed inside the lining. The monitoring and intelligent alarm system monitors the deformation and displacement data of the tunnel in real time. When the monitoring data reaches a set threshold, the intelligent alarm system will activate the alarm.

2. The construction method for seismic-resistant tunnel structures based on gradient grouting and composite lining according to claim 1, characterized in that, The high-risk area adopts the full-section grouting method, the medium-risk area adopts the interval grouting method, and the low-risk area adopts the local reinforcement grouting method.

3. The construction method for seismic-resistant tunnel structures based on gradient grouting and composite lining according to claim 2, characterized in that, The high-risk area is grouted with fast-setting ultrafine cement grout, with an initial setting time of ≤30 minutes, a grouting pressure of ≥2MPa, and a grout filling rate of ≥95%; the medium-risk area is grouted with slow-setting bentonite-cement mixture, with an initial setting time of 2~4 hours and a grouting pressure of 1~1.5MPa; the low-risk area is grouted with nano-silicate grouting agent for localized jet grouting, with a grouting pressure of ≤0.5MPa, and only the surface of the surrounding rock is reinforced.

4. The construction method for tunnel seismic-resistant structures based on gradient grouting and composite lining according to claim 3, characterized in that, The grouting thicknesses for the high-risk, medium-risk, and low-risk zones are all determined using the following formula: T = K⋅ln(Er / Es); In the formula, T is the grouting thickness, Er is the initial deformation modulus of the surrounding rock, Es is the target modulus, and K is the correction coefficient.

5. The construction method for seismic-resistant tunnel structures based on gradient grouting and composite lining according to claim 4, characterized in that, The elastic modulus of the flexible layer is 1 / 5 to 1 / 3 of that of the elastic modulus of the high-strength rigid layer.

6. The construction method for seismic-resistant tunnel structures based on gradient grouting and composite lining according to claim 1, characterized in that, During the pouring of the high-strength rigid layer, the grouting pressure and flow rate are intelligently adjusted in real time using a PID algorithm to match the deformation requirements of the surrounding rock.

7. The construction method for seismic-resistant tunnel structures based on gradient grouting and composite lining according to claim 1, characterized in that, The monitoring and intelligent alarm system installed inside the lining includes: an earth pressure cell installed at the rock-flexible layer interface for real-time monitoring of the contact pressure at the rock-flexible layer interface; a displacement meter installed at the energy-dissipating interlayer-high-strength rigid layer interface for real-time monitoring of the relative displacement at the energy-dissipating interlayer-high-strength rigid layer interface; and a fiber optic grating sensor and a piezoelectric accelerometer installed in the flexible layer. The fiber optic grating sensor is used to monitor stress changes and cracks in the flexible layer, and the piezoelectric accelerometer is used to record the dynamic response of the flexible layer in real time.

8. A tunnel seismic-resistant structure based on gradient grouting and composite lining constructed according to any one of claims 1-7, characterized in that, A composite lining is installed inside the tunnel surrounding rock. The composite lining includes a flexible layer, an energy-dissipating interlayer, and a high-strength rigid layer. The flexible layer is located inside the surrounding rock, the energy-dissipating interlayer is located inside the flexible layer, and the high-strength rigid layer is located inside the energy-dissipating interlayer. The flexible layer is cast using rubber particle modified polymer concrete or carbon fiber reinforced elastic concrete. The energy-dissipating interlayer uses damping alloy mesh or shape memory polymer material. The energy-dissipating interlayer is fixedly connected to the flexible layer by anchoring nails. The high-strength rigid layer is cast using steel fiber reinforced concrete formwork and grouting. A monitoring and intelligent alarm system is installed inside the lining to monitor the deformation and displacement of the tunnel's internal structure in real time.

9. The tunnel seismic-resistant structure based on gradient grouting and composite lining according to claim 8, characterized in that, The monitoring and intelligent alarm system includes an earth pressure cell installed at the interface between the surrounding rock and the flexible layer, a displacement meter installed at the interface between the energy dissipation interlayer and the high-strength rigid layer, a fiber optic grating sensor and a piezoelectric accelerometer installed inside the flexible layer, and an intelligent alarm system connected to the earth pressure cell, displacement meter, fiber optic grating sensor and piezoelectric accelerometer respectively.

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