Tunnel anti-seismic structure based on composite lining and gradient grouting and construction method of tunnel anti-seismic structure

Abstract

The invention discloses a tunnel anti-seismic structure based on gradient grouting and composite lining and a construction method thereof.The construction method comprises the steps that the geology of surrounding rock is detected, distribution of a weak area, a cavity area and a stable area of the surrounding rock is recognized, and the surrounding rock is divided into a high risk area, a medium risk area and a low risk area according to the detection result; different grouting modes, different paste and slurry proportions, different grouting parameters and different grouting thicknesses are adopted for conducting gradient grading grouting reinforcement on the risk areas of all levels; a flexible layer is poured on the inner side of the surrounding rock subjected to grouting reinforcement, an energy consumption interlayer is installed on the inner side of the flexible layer, and a high-strength rigid layer is poured and manufactured on the inner side of the energy consumption interlayer; a monitoring and intelligent alarm system is arranged in the lining and used for monitoring tunnel internal structure deformation and displacement data in real time. Through triple protection of rigid compression resistance, energy dissipation buffering and flexible energy release, the earthquake energy dissipation rate is increased, meanwhile, material waste is reduced through surrounding rock graded grouting, and the surrounding rock-lining rigidity matching degree is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel engineering construction, and in particular to a tunnel earthquake-resistant structure based on composite lining and gradient grouting and a construction method thereof. Background Art

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

[0003] Traditional tunnel seismic design primarily utilizes structural reinforcement and surrounding rock reinforcement. However, existing single tunnel seismic technology has significant limitations. In terms of structural reinforcement, increasing lining thickness and full-section reinforcement were commonly used to increase stiffness in the early stages. However, studies have shown that while excessive stiffness can reduce axial stress, it also increases shear and bending stresses. Furthermore, rigid structures are unable to effectively dissipate seismic energy and may exacerbate dynamic response. In recent years, the concept of flexible structures has gradually gained attention. However, if stiffness is too low, it may cause excessive displacements and affect tunnel stability. Grouting is commonly used for surrounding rock reinforcement. While conventional grouting techniques (such as full-section grouting and interval grouting) can improve the mechanical properties of the surrounding rock, they lack the ability to fine-tune the stiffness of different geological conditions (such as weak zones and fractured rock masses), resulting in insufficient matching of surrounding rock and lining stiffness. Especially under earthquake action, stiffness differences can easily lead to interfacial stress concentration, accelerating lining cracking. In addition, the existing grouting technology does not fully consider the correlation between the seismic wave frequency band and the dynamic characteristics of the surrounding rock, and the selection of reinforcement range and thickness lacks theoretical support; the singleness of material technology also limits the improvement of seismic resistance, 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 imbalance between structural rigidity and flexibility, insufficient targeted surrounding rock reinforcement, and uncoordinated 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 above background technology, such as the imbalance between rigidity and flexibility of the existing tunnel seismic technology structure, insufficient targeted surrounding rock reinforcement, and uncoordinated optimization of material properties, the present invention provides a tunnel seismic structure based on composite lining and gradient grouting and its construction method, aiming to achieve efficient energy dissipation and stress redistribution of the tunnel under seismic loads, while optimizing the surrounding rock grouting reinforcement method to save construction costs.

[0006] To achieve the above object, the present invention provides the following technical solutions:

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

[0008] S1. Grading grouting reinforcement of surrounding rock, specifically including: detecting the surrounding rock geology, identifying the distribution of weak areas, void areas, and stable areas; dividing the surrounding rock into high-risk areas, medium-risk areas, and low-risk areas based on the detection results and combined with experience and existing theories; and implementing graded grouting reinforcement of the surrounding rock using different grouting methods, different paste-slurry 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 the grouting-reinforced surrounding rock, specifically including: casting a flexible layer inside the surrounding rock, the flexible layer is used to absorb shear stress and bending stress, and the flexible layer is cast using rubber particle-modified polymer concrete or carbon fiber-reinforced elastic concrete; installing a fixed energy-absorbing interlayer inside the flexible layer, the energy-absorbing interlayer is made of a damping alloy grid or shape memory polymer material; and casting a high-strength rigid layer inside the energy-absorbing interlayer, the high-strength rigid layer is completed by grouting with steel fiber concrete formwork;

[0010] S3. A monitoring and intelligent alarm system is set up inside the lining. The monitoring and intelligent alarm system monitors the deformation and displacement related 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 a full-section grouting method, the medium-risk area adopts an interval grouting method, and the low-risk area adopts a local reinforcement grouting method.

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

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

[0014] T = K·ln(Er / Es);

[0015] Where 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 through a PID algorithm to match the deformation requirements of the surrounding rock.

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

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

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

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

[0022] The tunnel seismic resistance structure and construction method based on composite lining and gradient grouting proposed in the present invention significantly improve the seismic resistance of the tunnel through gradient graded grouting reinforcement of the surrounding rock, a three-layer composite lining structure of flexible layer-energy dissipation interlayer-high-strength rigid layer, and the installation of monitoring sensors and intelligent alarm systems. The three-layer composite lining structure of "flexible layer-energy dissipation interlayer-high-strength rigid layer" can achieve triple protection of "rigid compression resistance-energy dissipation buffer-flexible energy release", achieve a dynamic balance of rigidity and flexibility in the lining, and improve the seismic energy dissipation rate; by dividing the surrounding rock into high-risk areas, medium-risk areas, and low-risk areas, reasonable gradient graded grouting can reduce material waste and significantly improve the matching degree of surrounding rock-lining stiffness. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1Schematic diagram of the cross-section structure of the tunnel seismic resistant structure based on composite lining and gradient grouting according to the present invention;

[0024] Figure 2 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 flow chart of the tunnel seismic structure construction method based on composite lining and gradient grouting according to the present invention;

[0026] In the figure: 1. surrounding rock; 2. flexible layer; 3. energy-absorbing interlayer; 4. high-strength rigid layer; 5. earth pressure cell; 6. displacement meter; 7. fiber Bragg grating sensor; 8. piezoelectric accelerometer. DETAILED DESCRIPTION

[0027] The specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. The embodiments are exemplary and are only used to explain the present invention, and should not be understood as limiting the present invention. Obviously, the embodiments described in the present invention are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of the present invention.

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

[0029] Reference Figures 1 to 2 The present invention provides a tunnel seismic resistant structure based on gradient grouting and composite lining, comprising: a flexible layer arranged on the inner side of the tunnel surrounding rock, an energy-absorbing interlayer arranged on the inner side of the flexible layer, a high-strength rigid layer arranged on the inner side of the energy-absorbing interlayer, the flexible layer is cast by using rubber particle modified polymer concrete or carbon fiber reinforced elastic concrete, the energy-absorbing interlayer adopts damping alloy grid or shape memory polymer material, the energy-absorbing interlayer is fixedly connected to the flexible layer by anchor nails, and the high-strength rigid layer is cast by using steel fiber concrete formwork grouting; an earth pressure box is arranged at the interface of the surrounding rock-flexible layer, a displacement meter is arranged at the interface of the energy-absorbing interlayer-high-strength rigid layer, a fiber grating sensor and a piezoelectric accelerometer are arranged inside the flexible layer, and the earth pressure box, the displacement meter, the fiber grating sensor and the piezoelectric accelerometer are all connected to the intelligent alarm system.

[0030] Among them, the pressure box is used to monitor the contact pressure of the surrounding rock-flexible layer interface in real time, the displacement meter is used to monitor the relative displacement of the energy-absorbing interlayer-high-strength rigid layer interface in real time, the fiber grating sensor is used to monitor the stress changes and cracks of 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 provides a construction method for a tunnel seismic resistant structure based on gradient grouting and composite lining, comprising the following steps:

[0032] S1. Grading grouting reinforcement of surrounding rock, specifically including: detecting the surrounding rock geology, identifying the distribution of weak areas, void areas, and stable areas; dividing the surrounding rock into high-risk areas, medium-risk areas, and low-risk areas based on the detection results and combined with experience and existing theories; and implementing graded grouting reinforcement of the surrounding rock using different grouting methods, different paste-slurry 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 the grouting-reinforced surrounding rock, specifically including: casting a flexible layer inside the surrounding rock, the flexible layer is used to absorb shear stress and bending stress, and the flexible layer is cast using rubber particle-modified polymer concrete or carbon fiber-reinforced elastic concrete; installing a fixed energy-absorbing interlayer inside the flexible layer, the energy-absorbing interlayer is made of damping alloy grid or shape memory polymer material; and casting a high-strength rigid layer inside the energy-absorbing interlayer, the high-strength rigid layer is completed by grouting with steel fiber concrete formwork;

[0034] S3. A monitoring and intelligent alarm system is installed within the lining. This system monitors tunnel deformation and displacement in real time and intelligently activates the alarm system when the monitoring data reaches a set threshold. Specifically, this system includes an earth pressure cell at the interface between the flexible and flexible layers, a displacement meter at the interface between the energy-absorbing interlayer and the high-strength rigid layer, and fiber Bragg grating sensors and piezoelectric accelerometers embedded within the flexible layer.

[0035] High-risk areas use full-section grouting, medium-risk areas use interval grouting, and low-risk areas use local reinforcement grouting. High-risk areas use fast-setting ultrafine cement slurry for grouting, with an initial setting time of ≤30 minutes, a grouting pressure of ≥2 MPa, and a slurry filling rate of ≥95%. Medium-risk areas use slow-setting bentonite-cement mixed slurry for grouting, with an initial setting time of 2 to 4 hours and a grouting pressure of 1 to 1.5 MPa. Low-risk areas use nano-silicate grouting agents for localized jet grouting, with a grouting pressure of ≤0.5 MPa, and only reinforce the surrounding rock surface.

[0036] The grouting thickness in high-risk, medium-risk, and low-risk areas is determined using 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 the correction factor. 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 PID algorithm is used to intelligently adjust the grouting pressure and flow in real time to match the deformation requirements of the surrounding rock.

[0038] It should be noted that the high-strength rigid layer in the present invention can also be made by connecting reinforced concrete prefabricated panels, and the prefabricated panels are 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 in the scope of protection of the present invention.

Claims

1. A tunnel seismic structure construction method based on gradient grouting and composite lining, characterized in that: The following steps are involved: S1. Gradient graded grouting reinforcement of surrounding rock, specifically including: detecting the surrounding rock geology, identifying the distribution of weak areas, void areas, and stable areas; dividing the surrounding rock into high-risk areas, medium-risk areas, and low-risk areas based on the detection results and combined with experience and existing theories; and implementing graded grouting reinforcement of the surrounding rock using different grouting methods, different paste-slurry ratios, different grouting parameters, and different grouting thicknesses for the high-risk areas, medium-risk areas, and low-risk areas; S2. Composite lining construction based on the grouting-reinforced surrounding rock, specifically including: casting a flexible layer inside the surrounding rock, the flexible layer is used to absorb shear stress and bending stress, and the flexible layer is cast using rubber particle-modified polymer concrete or carbon fiber-reinforced elastic concrete; installing a fixed energy-absorbing interlayer inside the flexible layer, the energy-absorbing interlayer is made of a damping alloy grid or shape memory polymer material; and casting a high-strength rigid layer inside the energy-absorbing interlayer, the high-strength rigid layer being cast using steel fiber concrete formwork and grouting; S3. A monitoring and intelligent alarm system is set up inside the lining. The monitoring and intelligent alarm system monitors the deformation and displacement related data of the tunnel in real time. When the monitoring data reaches a set threshold, the intelligent alarm system activates an alarm.

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

4. The method for constructing a tunnel seismic-resistant structure based on gradient grouting and composite lining according to claim 3, characterized in that: The grouting thickness of the high-risk area, medium-risk area, and low-risk area is determined by the following 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 the correction coefficient.

5. The method for constructing a tunnel seismic-resistant structure 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 the elastic modulus of the high-strength rigid layer.

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

7. The method for constructing a tunnel seismic-resistant structure based on gradient grouting and composite lining according to claim 1, characterized in that: The monitoring and intelligent alarm system set up inside the lining includes: setting an earth pressure box at the interface of the surrounding rock-flexible layer for real-time monitoring of the contact pressure of the interface of the surrounding rock-flexible layer; setting a displacement meter at the interface of the energy-absorbing interlayer-high-strength rigid layer for real-time monitoring of the relative displacement of the interface of the energy-absorbing interlayer-high-strength rigid layer; and setting a fiber grating sensor and a piezoelectric accelerometer in the flexible layer, wherein the fiber 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. The tunnel seismic-resistant structure based on gradient grouting and composite lining is characterized by: A composite lining is arranged on the inner side of the tunnel surrounding rock, and the composite lining includes a flexible layer, an energy-absorbing interlayer, and a high-strength rigid layer. The flexible layer is arranged on the inner side of the surrounding rock, the energy-absorbing interlayer is arranged on the inner side of the flexible layer, and the high-strength rigid layer is arranged on the inner side of the energy-absorbing interlayer. The flexible layer is cast with rubber particle-modified polymer concrete or carbon fiber reinforced elastic concrete, the energy-absorbing interlayer is cast with damping alloy grid or shape memory polymer material, the energy-absorbing interlayer is fixedly connected to the flexible layer by anchor nails, and the high-strength rigid layer is cast with steel fiber concrete formwork grouting; a monitoring and intelligent alarm system is arranged inside the lining for real-time monitoring of the deformation and displacement of the internal structure of the tunnel.

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

Images