A ground penetrating radar detection and disease treatment method for deep-buried high-pressure tunnels

Abstract

The present application relates to a kind of ground penetrating radar detection and disease treatment method for deep high pressure tunnel, and the field measuring line is the net structure of two horizontal and two vertical, radar transmitting antenna continuously emits pulsed high frequency electromagnetic wave to underground, receiving antenna receives the reflection wave and transmission wave generated by interface or target body with electrical difference, the property of target body is determined according to the form, strength and its change of radar map reflection wave, and forecast is formed;Forecast content includes four aspects of whether there is broken rock stratum in the surrounding rock in front of working face, whether there is water-rich rock stratum in the surrounding rock in front of working face, whether there is the possibility of water or mud inrush in the surrounding rock in front of working face, and fault fracture zone and its water content in front of working face;Treatment scheme is formulated according to forecast content, combined with engineering profile summary, survey and construction design document and construction specification.

Description

Technical Field

[0001] This invention relates to the field of tunnel engineering technology, specifically to a ground-penetrating radar detection and treatment method for deep-buried high-voltage tunnels. Background Technology

[0002] With rapid economic development, highway tunnel construction faces significant safety hazards due to unclear geological conditions ahead of the tunnel face, uncertain surrounding rock grades, and unclear water-bearing status. Regular inspections are necessary to address these issues. Common methods for assessing fractured surrounding rock and water-bearing conditions at highway tunnel faces include TSP (Through-Survey Prediction), borehole drilling, and ground-penetrating radar (GPR), with GPR being the simplest and easiest to operate. However, existing detection and treatment technologies are often not well integrated, remaining separate. Therefore, research on methods for addressing fractured and water-bearing surrounding rock and grouting treatment in deeply buried high-pressure tunnels is crucial for developing integrated detection, grouting, and construction technologies, saving construction costs, and extending tunnel service life. Summary of the Invention

[0003] To address the problems existing in the background technology, this invention provides a ground-penetrating radar detection and treatment method for deeply buried high-pressure tunnels. By applying ground-penetrating radar detection technology to detect rock fragmentation and water abundance in deeply buried high-pressure tunnels, and using high-strength and low-permeability grouting materials for grouting treatment, the tunnel construction cost can be significantly reduced and the tunnel service life can be extended.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A ground-penetrating radar (GPR) detection and defect treatment method for deep-buried high-voltage tunnels is disclosed. The field survey lines are a two-horizontal-two-vertical mesh structure. The radar transmitting antenna continuously emits pulsed high-frequency electromagnetic waves into the ground, and the receiving antenna receives reflected and transmitted waves generated by interfaces or targets with electrical differences. The data is processed by the main unit to form a real-time radar map, determining the depth of the interface or target. Simultaneously, the nature of the target is determined and a prediction is generated based on the morphology, intensity, and changes of the reflected waves in the radar map. The nature of the target is defined by tunnel face parameters, including the fracturing and water-bearing conditions of the surrounding rock, photographs of the tunnel face, and geological sketches of the tunnel face. The prediction includes four aspects: whether there are fractured rock layers ahead of the tunnel face, whether there are water-bearing rock layers ahead of the tunnel face, whether there is a possibility of water or mud inrush ahead of the tunnel face, and the prediction of fault fracture zones ahead of the tunnel face and their water content.

[0006] Based on the forecast, project overview, survey and construction design documents, and construction specifications, a treatment plan is formulated. If the forecast indicates no fractured surrounding rock is found ahead of the tunnel face, the surrounding rock grade is less than or equal to level 3, and there is no karst water, underground river, or confined water, reinforcement grouting using 42mm diameter pre-anchor bolts is sufficient. If the forecast indicates fractured surrounding rock and high-pressure water-rich conditions at the tunnel face, then grouting using 42mm pre-anchor small guide pipes or 108mm pre-anchor large pipe roof grouting combined with radial grouting is required to comprehensively reinforce the tunnel surrounding rock and seal the high-pressure water-rich conditions. Alternatively, a curtain grouting scheme can be adopted, with the grouting material permeability coefficient being within 10. -9 cm / s~10 -10 cm / s, compressive strength not less than 20MPa.

[0007] Furthermore, the grouting material used for disease treatment is prepared by mixing acrylamide, N-N'-methylbisacrylamide, ammonium persulfate, dimethylaminonitrile, potassium ferricyanide, epichlorohydrin, lignin polyether polyol, lignin-based non-isocyanate polyurethane, and distilled water in a mass ratio of 10%:0.5%:1.0%:0.4%:0.01%:2%~5%:4%:1%~5%:74.09%~81.09%.

[0008] Furthermore, the method for preparing the grouting material includes: placing acrylamide, epichlorohydrin, and lignin-based non-isocyanate polyurethane in distilled water at 20℃~50℃ in proportion, and stirring at high speed at 100rpm~500rpm for 5min~15min to prepare grout A; placing N-N'-methylbisacrylamide, ammonium persulfate, dimethylaminonitrile, potassium ferricyanide, and lignin polyether polyol in distilled water at 40℃~60℃ in proportion, and stirring at high speed at 200rpm~300rpm for 10min~15min to prepare grout B; and preparing grout A and grout B in a mass ratio of 1:1 and stirring at high speed at 150rpm~300rpm for 5min~10min to prepare the grouting material.

[0009] Furthermore, the frequencies of ground-penetrating radar include 30MHz, 70MHz and 100MHz.

[0010] Furthermore, construction specifications include the "Specifications for Design of Highway Tunnels", the "Technical Specifications for Construction of Highway Tunnels", and the "Technical Specifications for Advanced Geological Prediction of Railway Tunnels".

[0011] The beneficial technical effects achieved by this invention are as follows:

[0012] The ground-penetrating radar detection technology of this invention has the characteristics of non-contact, long-distance, and rapid scanning detection. The grouting treatment method has the characteristics of being fast, efficient, and convenient to construct. The grouting material has the characteristics of being green and environmentally friendly, having a low permeability coefficient, and high strength. This significantly improves the service life of tunnels under construction and in operation, and can generate significant economic and social benefits. Attached Figure Description

[0013] Figure 1 This is a field survey line layout diagram for ground-penetrating radar detection of deeply buried high-voltage tunnels;

[0014] Figure 2 This is a geological sketch of the working face in Example 1;

[0015] Figure 3 This is the ground-penetrating radar map from Example 1;

[0016] Figure 4 This is a geological sketch of the working face in Example 2;

[0017] Figure 5 This is the ground-penetrating radar map from Example 2;

[0018] Figure 6 This is a geological sketch of the working face in Example 3;

[0019] Figure 7 This is the ground-penetrating radar map from Example 3. Detailed Implementation

[0020] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a method for ground-penetrating radar detection and treatment of defects in deeply buried high-voltage tunnels according to the present invention:

[0021] A ground-penetrating radar (GPR) detection and treatment method for deep-buried high-voltage tunnels involves several steps. First, GPR is used to detect the fractured and water-rich surrounding rock of the tunnel. The detection method includes the following steps: summarizing the project overview, stating the purpose of the forecast, determining the forecast content, the forecast principle, equipment selection, forecast basis, forecast plan, tunnel face properties, forecast results and interpretation, explanation of the fractured and water-rich surrounding rock, conclusions, and recommendations. The method then proceeds to a grouting treatment method for deep-buried high-voltage tunnels: based on the GPR forecast results and interpretation, the grouting drilling plan, drilling, selection of grouting materials, preparation of grouting materials, grouting, and evaluation of grouting effects are determined. The grouting material consists of acrylamide, N-N'-methylbisacrylamide, ammonium persulfate, dimethylaminonitrile, potassium ferricyanide, epichlorohydrin, lignin polyether polyol, lignin-based non-isocyanate polyurethane, and distilled water in a mass ratio of 10%:0.5%:1.0%:0.4%:0.01%:2%~5%:4%:1%~5%:74.09%~81.09%. The grouting material preparation method includes: Preparing grout A by placing acrylamide, epichlorohydrin, and lignin-based non-isocyanate polyurethane in distilled water at 20℃~50℃ and stirring at 100rpm~500rpm for 5min~15min; Preparing grout B by placing N-N'-methylbisacrylamide, ammonium persulfate, dimethylaminonitrile, potassium ferricyanide, and lignin polyether polyol in distilled water at 40℃~60℃ and stirring at 200rpm~300rpm for 10min~15min; Preparing grout B by mixing grout A and B in a 1:1 mass ratio and stirring at 150rpm~300rpm for 5min~10min. The grouting material must be prepared and used immediately, and should not be stored separately for more than 3 hours. The permeability coefficient of the grouting material should be within 10. -9 cm / s~10 -10 cm / s, compressive strength not less than 20MPa.

[0022] Unless otherwise specified, all percentage contents in this application document refer to mass percentage contents.

[0023] Example 1

[0024] A method for detecting the fractured and water-rich surrounding rock of deeply buried high-pressure tunnels using ground-penetrating radar (GPR) and for grouting treatment refers to a method that utilizes GPR to detect the fractured and water-rich surrounding rock of deeply buried high-pressure tunnels. The method mainly includes the following steps: a summary of the project overview, a statement of the forecasting purpose, determination of the forecasting content, forecasting principles, equipment selection, forecasting basis, forecasting scheme, tunnel face properties, forecasting results and interpretation, explanation of the fractured and water-rich surrounding rock conditions, and conclusions and recommendations. The project overview mainly includes tunnel depth, tunnel length, surrounding rock pressure, and surrounding rock fracture / grade. The forecasting purpose is based on the exploration data, which indicates a complex geological structure at the tunnel site. Geological surveys, excavations, geophysical exploration, and drilling have revealed potential adverse geological factors that could pose safety hazards during construction. Accurate detection of the rock mass ahead of the tunnel face is essential during tunnel excavation to effectively prevent geological disasters and engineering accidents, accelerate project progress, and reduce costs. The forecasting content mainly includes four aspects: whether there are fractured rock layers ahead of the tunnel face, whether there are water-rich rock layers ahead of the tunnel face, whether there is a possibility of water or mud inrush ahead of the tunnel face, and the forecasting of fault fracture zones ahead of the tunnel face and their water content. The forecasting principle is based on the radar transmitting antenna continuously emitting pulsed high-frequency electromagnetic waves underground. When encountering interfaces or targets with different electrical properties (different dielectric constants and conductivity), reflected and transmitted waves are generated. The receiving antenna receives the reflected waves and transmits them to the host computer via a cable, forming a real-time time profile on the host computer's display screen. The depth of the interface or target body is determined based on the recorded arrival time of the reflected wave and the propagation speed of the electromagnetic wave in the medium. Simultaneously, the nature of the target body is determined based on factors such as the shape, intensity, and changes of the reflected wave. Equipment selection primarily relies on choosing the ground-penetrating radar frequency based on the predicted depth; typically, 30MHz is chosen. The prediction is based on the "Highway Tunnel Design Specification" (JTG 3370.1-2018), the "Highway Tunnel Construction Technical Specification" (JTG / T 3660-2020), the "Railway Tunnel Advanced Geological Prediction Technical Specification" (Q / CR 9217-2015), and existing tunnel survey and construction design documents. The prediction scheme mainly includes: a two-horizontal and two-vertical mesh structure for the ground-penetrating radar field survey lines; providing face-of-face properties parameters based on the ground-penetrating radar map, such as the fracturing and water-rich conditions of the surrounding rock, along with face-of-face photographs and geological sketches (see 2); data processing; interpretation of the data processing results; and conclusions and recommendations.

[0025] Based on the variation characteristics of the amplitude and phase of ground-penetrating radar waves, see Figure 3The ground-penetrating radar detection depth was 40m, and the surrounding rock was classified as Class V, composed of moderately weathered limestone. It featured densely developed joints, with fissures mostly filled with clay. The area 25-30m ahead of the tunnel was rich in karst fissure water. The rock mass was relatively fractured, and the overall stability of the surrounding rock was poor, making it prone to rockfalls and collapses. No rockfalls were observed during the detection. The surrounding rock in this section is mainly composed of moderately weathered limestone with well-developed joints and fissures mostly filled with clay. The rock mass is relatively fractured, and the interlayer bonding is generally poor. Low-frequency signals indicate well-developed joints and fissures, with abundant fissure water, mostly in droplet form, which easily leads to rockfalls and collapses. The overall stability of the surrounding rock is poor. It is recommended that the surrounding rock be classified as Class V, with pre-excavation support and timely post-excavation support to prevent face collapse.

[0026] Post-excavation recommendations: Implement pre-excavation support before excavation and promptly reinforce the tunnel face after excavation to prevent rockfalls and collapses. During construction, the invert arch should be continuously monitored. When installing the steel arch frame, pay attention to potential rockfalls at the arch crown. It is recommended to conduct thorough tunnel monitoring and measurement, and based on periodic monitoring, establish tunnel deformation early warning levels to ensure tunnel construction safety.

[0027] The method for grouting treatment of deep-buried high-pressure tunnels mainly includes the following steps: determining the grouting drilling scheme, drilling, selection of grouting materials, preparation of grouting materials, grouting, and evaluation of grouting effect based on the ground-penetrating radar (GPR) forecast results and interpretation; determining the drilling scheme, drilling, selection of grouting materials, preparation of grouting materials, grouting, and evaluation of grouting effect based on GPR detection results; selecting a drilling diameter of 108mm, a drilling depth of 30m, and 105 drilling holes based on the grouting scheme; selecting the grouting material ratio based on the tunnel GPR detection results and the influence of the tunnel on the pressure and permeability coefficient of the grouting material; preparing the grouting material according to a certain ratio and process; using a high-pressure grouting pump or a polymer-specific chemical grouting pump for water-rich grouting; and comprehensively analyzing the grouting effect using water pressure tests, core sampling tests, and GPR to measure compressive strength, permeability coefficient, etc. The grouting material consists of acrylamide, N-N'-methylbisacrylamide, ammonium persulfate, dimethylaminonitrile, potassium ferricyanide, epichlorohydrin, lignin polyether polyol, lignin-based non-isocyanate polyurethane, and distilled water in a mass ratio of 10%:0.5%:1.0%:0.4%:0.01%:5%:4%:5%:74.09%. The grouting material preparation method includes: Preparing grout A by mixing acrylamide, epichlorohydrin, and lignin-based non-isocyanate polyurethane in a specific ratio in distilled water at 30°C and stirring at 300 rpm for 10 minutes; preparing grout B by mixing N-N'-methylbisacrylamide, ammonium persulfate, dimethylaminonitrile, potassium ferricyanide, and lignin polyether polyol in a specific ratio in distilled water at 40°C and stirring at 200 rpm for 10 minutes; and preparing the grouting material by mixing grouts A and B in a 1:1 mass ratio and stirring at 300 rpm for 10 minutes. The grouting material must be prepared and used immediately, and should not be stored separately for more than 3 hours. The permeability coefficient of the grouting material is 10. -10 cm / s, compressive strength is 48.5MPa.

[0028] Example 2

[0029] A method for detecting the fractured and water-rich conditions of the surrounding rock in a deeply buried high-pressure tunnel using ground-penetrating radar (GPR) and for grouting treatment, mainly includes the following steps: a summary of the project overview, a statement of the forecast purpose, a determination of the forecast content, a forecast principle, equipment selection, forecast basis, a forecast plan, the nature of the tunnel face, forecast results and interpretation, an explanation of the fractured and water-rich conditions of the tunnel surrounding rock, and conclusions and recommendations. The project overview mainly includes tunnel depth, tunnel length, surrounding rock pressure, and surrounding rock fracture / grade. The forecasting purpose is based on the exploration data, which indicates a complex geological structure at the tunnel site. Geological surveys, excavations, geophysical exploration, and drilling have revealed potential adverse geological factors that could pose safety hazards during construction. Accurate detection of the rock mass ahead of the tunnel face is essential during tunnel excavation to effectively prevent geological disasters and engineering accidents, accelerate project progress, and reduce costs. The forecasting content mainly includes four aspects: whether there are fractured rock layers ahead of the tunnel face, whether there are water-rich rock layers ahead of the tunnel face, whether there is a possibility of water or mud inrush ahead of the tunnel face, and the forecasting of fault fracture zones ahead of the tunnel face and their water content. The forecasting principle is based on the radar transmitting antenna continuously emitting pulsed high-frequency electromagnetic waves underground. When encountering interfaces or targets with different electrical properties (different dielectric constants and conductivity), reflected and transmitted waves are generated. The receiving antenna receives the reflected waves and transmits them to the host computer via cable, forming a real-time time profile on the host computer's display screen. Based on the recorded arrival time of the reflected waves and the calculated propagation speed of electromagnetic waves in the medium, the depth of the interface or target is determined; simultaneously, the nature of the target is determined based on factors such as the shape, strength, and changes of the reflected waves. Equipment selection primarily relies on choosing the ground-penetrating radar frequency based on the predicted depth; typically, 30MHz is chosen. The prediction is based on the "Highway Tunnel Design Specification" (JTG 3370.1-2018), the "Highway Tunnel Construction Technical Specification" (JTG / T 3660-2020), the "Railway Tunnel Advanced Geological Prediction Technical Specification" (Q / CR 9217-2015), and existing tunnel survey and construction design documents. The prediction scheme mainly includes: the ground-penetrating radar's field survey lines forming a two-horizontal and two-vertical mesh structure; providing face-of-excavation parameters based on the ground-penetrating radar map, such as the fracturing and water-rich conditions of the surrounding rock, along with face-of-excavation photographs and geological sketches (see...). Figure 4 Data processing, interpretation of the results, and conclusions and recommendations are provided.

[0030] Based on the variation characteristics of the amplitude and phase of ground-penetrating radar waves, see Figure 5The ground-penetrating radar detection depth is 150m, and the surrounding rock is classified as Class IV, containing a large amount of fractured surrounding rock, mainly composed of strongly weathered marl. The surrounding rock in this section is primarily composed of strongly weathered marl, with fractured rock mass, well-developed joints and fissures, exhibiting a fragmented structure and poor interlayer bonding. The large amplitude and multiple oscillations of electromagnetic waves suggest that the surrounding rock in this section is karst-developed and filled with mudstone. Karst development in some areas may present cavities or dissolution channels; the arch is prone to collapse, rockfall, and other adverse geological conditions. The overall stability of the surrounding rock is poor, and a Class IV surrounding rock classification is recommended. Pre-excavation support should be implemented to prevent face collapse.

[0031] Post-excavation recommendations: It is suggested to use deeper boreholes or advanced horizontal drilling to verify abnormal sections. Pre-excavation support should be implemented, and support should be provided promptly after excavation to prevent rockfalls and collapses at the tunnel face. The invert arch should be monitored closely during construction. When installing the steel arch frame, attention should be paid to potential rockfalls at the arch crown. Thorough tunnel monitoring and measurement should be conducted, and based on periodic monitoring, a tunnel deformation early warning system should be established to ensure tunnel construction safety.

[0032] The method for grouting treatment of deep-buried high-pressure tunnels mainly includes the following steps: determining the grouting drilling scheme, drilling, selection of grouting materials, preparation of grouting materials, grouting, and evaluation of grouting effect based on the ground-penetrating radar (GPR) forecast results and interpretation; when GPR detection results show that the surrounding rock is fractured and high-pressure water-rich at the tunnel face, it is necessary to use 42mm advanced small guide pipe grouting combined with radial grouting to comprehensively reinforce the tunnel surrounding rock and seal the high-pressure water-rich conditions in the tunnel. Based on the grouting scheme, a drilling diameter of 42mm, a drilling depth of 15m, and 35 drilling holes are selected; the grouting material mix ratio is selected based on the tunnel GPR detection results and the influence of the tunnel on the pressure and permeability coefficient of the grouting material; the grouting material is prepared according to a certain mix ratio and process; high-pressure grouting pumps or polymer-specific chemical grouting pumps are used for water-rich grouting; and the grouting effect is comprehensively analyzed using water pressure tests, core sampling tests, and GPR to measure compressive strength, permeability coefficient, etc. The grouting material consists of acrylamide, N-N'-methylbisacrylamide, ammonium persulfate, dimethylaminonitrile, potassium ferricyanide, epichlorohydrin, lignin polyether polyol, lignin-based non-isocyanate polyurethane, and distilled water in a mass ratio of 10%:0.5%:1.0%:0.4%:0.01%:2%:4%:1%:81.09%. The grouting material preparation method includes: Preparing grout A by mixing acrylamide, epichlorohydrin, and lignin-based non-isocyanate polyurethane in a specific ratio in distilled water at 30°C and stirring at 500 rpm for 5 minutes; preparing grout B by mixing N-N'-methylbisacrylamide, ammonium persulfate, dimethylaminonitrile, potassium ferricyanide, and lignin polyether polyol in a specific ratio in distilled water at 40°C and stirring at 300 rpm for 10 minutes; and preparing the grouting material by mixing grouts A and B in a 1:1 mass ratio and stirring at 150 rpm for 5 minutes. The grouting material must be prepared and used immediately, and should not be stored separately for more than 3 hours. The permeability coefficient of the grouting material is 10. -9 cm / s, compressive strength is 35.2MPa.

[0033] Example 3

[0034] A method for detecting the fractured and water-rich conditions of the surrounding rock in a deeply buried high-pressure tunnel using ground-penetrating radar (GPR) and for grouting treatment, mainly includes the following steps: a summary of the project overview, a statement of the forecast purpose, a determination of the forecast content, a forecast principle, equipment selection, forecast basis, a forecast plan, the nature of the tunnel face, forecast results and interpretation, an explanation of the fractured and water-rich conditions of the tunnel surrounding rock, and conclusions and recommendations. The project overview mainly includes tunnel depth, tunnel length, surrounding rock pressure, and surrounding rock fracture / grade. The forecasting purpose is based on the exploration data, which indicates a complex geological structure at the tunnel site. Geological surveys, excavations, geophysical exploration, and drilling have revealed potential adverse geological factors that could pose safety hazards during construction. Accurate detection of the rock mass ahead of the tunnel face is essential during tunnel excavation to effectively prevent geological disasters and engineering accidents, accelerate project progress, and reduce costs. The forecasting content mainly includes four aspects: whether there are fractured rock layers ahead of the tunnel face, whether there are water-rich rock layers ahead of the tunnel face, whether there is a possibility of water or mud inrush ahead of the tunnel face, and the forecasting of fault fracture zones ahead of the tunnel face and their water content. The forecasting principle is based on the radar transmitting antenna continuously emitting pulsed high-frequency electromagnetic waves underground. When encountering interfaces or targets with different electrical properties (different dielectric constants and conductivity), reflected and transmitted waves are generated. The receiving antenna receives the reflected waves and transmits them to the host computer via cable, forming a real-time time profile on the host computer's display screen. Based on the recorded arrival time of the reflected waves and the calculated propagation speed of electromagnetic waves in the medium, the depth of the interface or target is determined; simultaneously, the nature of the target is determined based on factors such as the shape, strength, and changes of the reflected waves. Equipment selection primarily relies on choosing the ground-penetrating radar frequency based on the predicted depth; typically, 30MHz is chosen. The prediction is based on the "Highway Tunnel Design Specification" (JTG 3370.1-2018), the "Highway Tunnel Construction Technical Specification" (JTG / T 3660-2020), the "Railway Tunnel Advanced Geological Prediction Technical Specification" (Q / CR 9217-2015), and existing tunnel survey and construction design documents. The prediction scheme mainly includes: the ground-penetrating radar's field survey lines forming a two-horizontal and two-vertical mesh structure; providing face-of-excavation parameters based on the ground-penetrating radar map, such as the fracturing and water-rich conditions of the surrounding rock, along with face-of-excavation photographs and geological sketches (see...). Figure 6 Data processing, interpretation of the results, and conclusions and recommendations are provided.

[0035] Based on the variation characteristics of the amplitude and phase of ground-penetrating radar waves, see Figure 7The ground-penetrating radar detection depth was 30m, and the surrounding rock grade was Class V. The tunnel face was mainly composed of strongly weathered marl with well-developed joints, fractured rock mass, and poor overall stability, making it prone to rockfalls and collapses. No rockfalls were observed during the detection. The surrounding rock in this section is mainly composed of strongly weathered marl with well-developed joints, fractured rock mass, and poor interlayer bonding. The electromagnetic wave phase axis was intermittent, with moderate amplitude and relatively chaotic waveform, suggesting that the surrounding rock in this section has poor rock mass integrity, well-developed joints and fissures in some areas, and relatively abundant fissure water; it is prone to rockfalls and collapses, and has poor overall stability. It is recommended that the surrounding rock grade be Class V, as the burial depth is relatively shallow and prone to roof falls. It is recommended to strengthen surface and internal reinforcement measures.

[0036] Post-excavation recommendations: It is suggested to use deeper boreholes or advanced horizontal drilling to verify abnormal sections. Pre-excavation support should be implemented, and support should be provided promptly after excavation to prevent rockfalls and collapses at the tunnel face. The invert arch should be monitored closely during construction. When installing the steel arch frame, attention should be paid to potential rockfalls at the arch crown. Thorough tunnel monitoring and measurement should be conducted, and based on periodic monitoring, a tunnel deformation early warning system should be established to ensure tunnel construction safety.

[0037] The method for grouting treatment of deep-buried high-pressure tunnels mainly includes the following steps: determining the grouting drilling scheme, drilling, selection of grouting materials, preparation of grouting materials, grouting, and evaluation of grouting effect based on the ground-penetrating radar (GPR) forecast results and interpretation; when GPR detection results show that the surrounding rock is fractured and high-pressure water-rich at the tunnel face, it is necessary to use 42mm advanced small guide pipe grouting combined with radial grouting to comprehensively reinforce the tunnel surrounding rock and seal the high-pressure water-rich conditions in the tunnel. Based on the grouting scheme, a drilling diameter of 42mm, a drilling depth of 30m, and 70 drilling holes are selected; the grouting material mix ratio is selected based on the tunnel GPR detection results and the influence of the tunnel on the pressure and permeability coefficient of the grouting material; the grouting material is prepared according to a certain mix ratio and process; high-pressure grouting pumps or polymer-specific chemical grouting pumps are used for water-rich grouting; and the grouting effect is comprehensively analyzed using water pressure tests, core sampling tests, and GPR to measure compressive strength, permeability coefficient, etc. The grouting material consists of acrylamide, N-N'-methylbisacrylamide, ammonium persulfate, dimethylaminonitrile, potassium ferricyanide, epichlorohydrin, lignin polyether polyol, lignin-based non-isocyanate polyurethane, and distilled water in a mass ratio of 10%:0.5%:1.0%:0.4%:0.01%:3%:4%:2%:79.09%. The grouting material preparation method includes: Preparing grout A by mixing acrylamide, epichlorohydrin, and lignin-based non-isocyanate polyurethane in a specific ratio in distilled water at 50°C and stirring at 100 rpm for 15 minutes; preparing grout B by mixing N-N'-methylbisacrylamide, ammonium persulfate, dimethylaminonitrile, potassium ferricyanide, and lignin polyether polyol in a specific ratio in distilled water at 60°C and stirring at 200 rpm for 15 minutes; and preparing the grouting material by mixing grouts A and B in a 1:1 mass ratio and stirring at 150 rpm for 10 minutes. The grouting material must be prepared and used immediately, and should not be stored separately for more than 3 hours. The permeability coefficient of the grouting material should be within 2 × 10⁻⁶. -10 cm / s, compressive strength is 45.0MPa.

[0038] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Various changes that can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for ground-penetrating radar detection and treatment of defects in deeply buried high-voltage tunnels, characterized in that, The field survey lines form a grid structure of two horizontal and two vertical lines. The radar transmitting antenna continuously emits pulsed high-frequency electromagnetic waves into the ground, while the receiving antenna receives reflected and transmitted waves generated by interfaces or targets with electrical differences. These waves are processed by the main unit to form a real-time radar map, determining the depth of the interface or target. Simultaneously, the nature of the target is determined and a forecast is generated based on the shape, intensity, and changes of the reflected waves in the radar map. The nature of the target is defined by the face properties, including the fracturing and water-bearing conditions of the surrounding rock, photographs of the face, and geological sketches of the face. The forecast includes four aspects: whether there are fractured rock layers ahead of the face, whether there are water-bearing rock layers ahead of the face, whether there is a possibility of water or mud inrush ahead of the face, and the fault fracture zone ahead of the face and its water content. Based on the forecast, project overview, survey and construction design documents, and construction specifications, a treatment plan is formulated. If the forecast indicates no fractured surrounding rock is found ahead of the tunnel face, the surrounding rock grade is less than or equal to level 3, and there is no karst water, underground river, or confined water, reinforcement grouting using 42mm diameter pre-anchor bolts is sufficient. If the forecast indicates fractured surrounding rock and high-pressure water-rich conditions at the tunnel face, then grouting using 42mm pre-anchor small guide pipes or 108mm pre-anchor large pipe roof grouting combined with radial grouting is required to comprehensively reinforce the tunnel surrounding rock and seal the high-pressure water-rich conditions. Alternatively, a curtain grouting scheme can be adopted, with the grouting material permeability coefficient being within 10. -9 cm / s ~10 -10 cm / s, compressive strength not less than 20 MPa; The grouting material used for treating the disease is prepared by mixing acrylamide, N-N'-methylbisacrylamide, ammonium persulfate, dimethylaminonitrile, potassium ferricyanide, epichlorohydrin, lignin polyether polyol, lignin-based non-isocyanate polyurethane, and distilled water in a mass ratio of 10%:0.5%:1.0%:0.4%:0.01%:2%~5%:4%:1%~5%:74.09%~81.09%. The method for preparing the grouting material includes: placing acrylamide, epichlorohydrin, and lignin-based non-isocyanate polyurethane in distilled water at 20°C~50°C in proportion, and stirring at high speed at 100rpm~500rpm for 5min~15min to prepare grout A; placing N-N'-methylbisacrylamide, ammonium persulfate, dimethylaminonitrile, potassium ferricyanide, and lignin polyether polyol in distilled water at 40°C~60°C in proportion, and stirring at high speed at 200rpm~300rpm for 10min~15min to prepare grout B; and mixing grout A and grout B at a mass ratio of 1:1 and stirring at high speed at 150rpm~300rpm for 5min~10min to prepare the grouting material.

2. The method for ground-penetrating radar detection and treatment of defects in deeply buried high-voltage tunnels according to claim 1, characterized in that, Ground penetrating radar frequencies include 30MHz, 70MHz and 100MHz.

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