Self-adaptive flyover crossing tunnel surrounding rock reinforcing method

Abstract

The invention relates to the technical field of reinforcing methods, in particular to a self-adaptive flyover crossing tunnel surrounding rock reinforcing method. The method mainly aims at solving the problems that during urban underground double-hole or flyover crossing tunnel construction, surrounding rock in a crossing area is disturbed by double construction, the stress state changes severely, weak surrounding rock of a tiny-clear-distance flyover crossing tunnel is prone to deformation and instability, a traditional reinforcing method lacks dynamic adaptability, and an existing intelligent monitoring system is not effectively linked with reinforcing measures. According to the technical scheme, the method comprises the following steps that firstly, detailed investigation is conducted on the geological condition of an area where a tunnel is located, and a reinforcement scheme is designed according to the geological investigation result; and 2, before the tunnel is excavated, grout is injected into the surrounding rock through the grouting holes, and adjustable anchor rods are installed in front of the excavation face at a preset external insertion angle along the excavation contour line. The method has the advantages that the safety and durability of tunnel construction are improved, the construction cost is reduced, and the construction efficiency and accuracy are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of reinforcement methods, and particularly to an adaptive reinforcement method for surrounding rock of a three-dimensional interchange tunnel. Background Art

[0002] Urban underground tunnel construction often has to face complex geological conditions and limited construction space. For example, when constructing a double-tunnel or three-dimensional interchange tunnel, when the newly built tunnel needs to pass through from one side of the existing tunnel, the surrounding rock in the intersection area will be affected by the construction activities from two directions. This double construction disturbance may not only cause a drastic change in the stress state of the surrounding rock, but also lead to the instability of the tunnel structure, seriously affecting the safety and durability of the tunnel.

[0003] During the construction and operation of a three-dimensional interchange tunnel with a very small clear distance, the deformation and instability of soft surrounding rock are common safety hazards. Due to the small tunnel spacing and strong interaction between the surrounding rocks, the reinforcement work becomes extremely complex. Traditional reinforcement methods, such as grouting reinforcement and bolt support, although can improve the stability of the surrounding rock to a certain extent, often lack dynamic adaptability and cannot respond in a timely manner according to the real-time changes of the surrounding rock. Especially in soft surrounding rock, due to the complex geological conditions, the deformation and stress state of the surrounding rock may change at any time, and traditional reinforcement methods often fail to achieve the ideal reinforcement effect.

[0004] In the prior art, although some intelligent monitoring systems are applied to tunnel engineering to monitor the deformation and stress state of the surrounding rock, most of these systems are only used for data collection and analysis and do not effectively link with the reinforcement measures. Therefore, in the actual reinforcement process, it is still necessary for manual to make judgments and decisions based on the monitoring data, which is not only inefficient but also may lead to untimely or inappropriate reinforcement measures due to human factors. In view of this, the present invention proposes an adaptive reinforcement method for surrounding rock of a three-dimensional interchange tunnel. Summary of the Invention

[0005] The object of the present invention is to address the problems in the background art that during the construction of urban underground double-tunnel or three-dimensional interchange tunnels, the surrounding rock in the intersection area is affected by double construction disturbances, the stress state changes drastically, the soft surrounding rock of the three-dimensional interchange tunnel with a very small clear distance is prone to deformation and instability, traditional reinforcement methods lack dynamic adaptability, existing intelligent monitoring systems do not effectively link with the reinforcement measures, and manual decision-making for reinforcement is inefficient and prone to errors, and to propose an adaptive reinforcement method for surrounding rock of a three-dimensional interchange tunnel.

[0006] The technical solution of the present invention: An adaptive reinforcement method for surrounding rock of a three-dimensional interchange tunnel, comprising the following steps:

[0007] Step 1: Conduct a detailed investigation of the geological conditions in the tunnel area, and design a reinforcement plan according to the geological investigation results;

[0008] Step 2: Before tunnel excavation, inject slurry into the surrounding rock through grouting holes, and install adjustable bolts along the excavation contour line at a preset external insertion angle towards the front of the excavation face; the adjustable bolt includes an anchoring main body component, an adjustable anchoring component, and an expansion induction mechanism; the anchoring main body component is used to strengthen the strength of the surrounding rock; the adjustable anchoring component is used to perform secondary strengthening on the strength of the surrounding rock based on the anchoring main body component; the expansion induction mechanism is used to induce the operation of the adjustable anchoring component based on a control signal.

[0009] Step 3: Install sensors at key positions in the tunnel construction area and build an Internet of Things data transmission system.

[0010] Step 4: Establish a data analysis platform, perform real-time analysis and processing on the sensor data, and establish a three-dimensional surrounding rock strength distribution map.

[0011] Step 5: Based on the three-dimensional surrounding rock strength distribution map, obtain the area that needs to be strengthened with support, generate a control signal, and send it to the expansion induction mechanism in this area for secondary reinforcement.

[0012] Optionally, the steps for building the Internet of Things data transmission system include: selecting the type of sensor according to the design parameters and construction requirements of the tunnel; installing sensors at key positions in the tunnel construction area; selecting Internet of Things hardware devices and arranging sensor nodes; according to the environmental conditions and data transmission requirements in the tunnel construction area, selecting a network connection method and a data transmission protocol; building an Internet of Things data management platform to receive, store, and process sensor data.

[0013] Optionally, the key positions include the crown, side walls, floor, and excavation face.

[0014] Optionally, the sensors include displacement sensors, pressure sensors, and temperature sensors.

[0015] Optionally, the steps for constructing the three-dimensional surrounding rock strength distribution map include: obtaining the data output by the sensors in real time; preprocessing the obtained data; extracting the key features representing the state of the surrounding rock from the preprocessed data; using three-dimensional modeling tools, combining the design parameters and construction requirements of the tunnel, and establishing a three-dimensional model of the tunnel; in the three-dimensional model, combining the sensor layout positions and the collected data with the actual geological conditions for refined modeling; based on the extracted key features and the three-dimensional model, drawing a three-dimensional surrounding rock strength distribution map; in the three-dimensional surrounding rock strength distribution map, using different colors or grayscales to represent different strength grades of the surrounding rock.

[0016] Optionally, the key features include displacement, pressure, strain, and temperature change rate.

[0017] Optionally, it further includes establishing a prediction model for the change trend of surrounding rock; obtaining the data collected by sensors; normalizing the collected data and dividing it into a training set and a test set; selecting a model algorithm according to the complexity and non-linearity characteristics of the surrounding rock deformation; training the model with the training set data, adjusting the model parameters to minimize the prediction error; validating the model with the test set data, evaluating the prediction accuracy and generalization ability of the model, and obtaining a prediction model for the change trend of surrounding rock; inputting the real-time collected data into the trained prediction model for the change trend of surrounding rock to predict the future deformation trend of the surrounding rock.

[0018] Optionally, the anchoring main body component includes a bolt rod body; one end of the bolt rod body is provided with a nut and a first backing plate, the nut is threadedly connected to the bolt rod body, and the bolt rod body penetrates through the first backing plate and is in sliding fit with the first backing plate;

[0019] The adjustable anchoring assembly includes a second backing plate, the second backing plate is located between the nut and the first backing plate, the bolt rod body penetrates through the second backing plate and is in sliding fit with the second backing plate, and the first backing plate and the second backing plate are engaged with each other; a washer is arranged between the second backing plate and the nut, and the bolt rod body penetrates through the washer and is in sliding fit with the washer;

[0020] The expansion induction mechanism includes a conical groove opened on any side close to the contact surface between the first backing plate and the second backing plate, an annular block is placed in the conical groove, the side wall of the annular block is in contact with the inner wall of the conical groove and the first backing plate respectively, and an expansion material is placed between the annular block and the conical groove; a water storage tank is arranged in the first backing plate, and the water storage tank is communicated with the conical groove; a sealing assembly for temporarily blocking the water storage tank and the conical groove is arranged at the communication position between the water storage tank and the conical groove; a water pressure boosting assembly is arranged in the water storage tank.

[0021] Optionally, the water pressure boosting assembly includes a compression spring and a piston plate; the piston plate is in sliding fit with the water storage tank, and both ends of the compression spring are fixedly connected to the piston plate and the inner wall of the water storage tank respectively.

[0022] Optionally, the sealing assembly includes a limiting block and a piston block; an expansion channel and a drainage channel are sequentially communicated between the conical groove and the water storage tank, the cross-sectional area of the expansion channel is larger than that of the drainage channel, and the piston block is in sliding fit with the drainage channel; a limiting groove is communicated with one side of the drainage channel, the limiting block is in sliding fit with the limiting groove, a tension spring is arranged between the limiting block and the limiting groove, one end of the limiting block away from the tension spring extends into the drainage channel, a fuse is arranged at one end of the limiting block away from the tension spring, the other end of the fuse is fixedly connected to the inner wall of the drainage channel, and the fuse is signal-connected to a control module, and the control module is used to receive a control signal to control the fusing of the fuse.

[0023] In summary, the present application includes at least one of the following beneficial technical effects:

[0024] In the geological exploration stage of the present invention, by combining the preliminary exploration and detailed survey stages, and comprehensively applying various technical means such as data collection, field investigation, ground penetrating radar, core drilling, and numerical simulation, the geological conditions of the tunnel area are comprehensively and deeply grasped. Based on the reinforcement plan designed thereby, the reinforcement method and materials can be accurately selected according to different surrounding rock characteristics, significantly improving the pertinence of construction;

[0025] Furthermore, before tunnel excavation, double reinforcement is carried out by grouting and installing adjustable bolts. The grouting can fill the voids in the surrounding rock and enhance its integrity; the anchoring main component, adjustable anchoring component, and expansion induction mechanism of the adjustable bolt cooperate with each other, not only strengthening the strength of the surrounding rock, but also realizing secondary tension under the action of a control signal, effectively coping with the changes in the surrounding rock and strongly guaranteeing the stability of the surrounding rock;

[0026] Furthermore, by building an Internet of Things data transmission system, various sensors such as displacement, pressure, and temperature are installed at key positions in the tunnel to realize real-time monitoring of the surrounding rock state. The sensor data is processed through a data analysis platform to construct a three-dimensional surrounding rock strength distribution map, which can intuitively reflect the changes in the surrounding rock strength. Once an area that needs to be strengthened is found, the adjustable bolt can be immediately controlled through the Internet of Things data management platform for reinforcement, truly realizing real-time linkage between monitoring and reinforcement;

[0027] Furthermore, by establishing a prediction model for the change trend of the surrounding rock, after cleaning and normalizing the data collected by the sensors, the training set and test set are divided, and a suitable algorithm is selected for training and verification. The model is integrated into the Internet of Things data management platform, which can predict the future deformation trend of the surrounding rock in real time. After setting the warning threshold, the warning mechanism can be triggered in time when the predicted value exceeds the threshold, providing sufficient time for construction personnel to take countermeasures and effectively reducing safety risks;

[0028] Furthermore, the adaptive three-dimensional intersection tunnel surrounding rock reinforcement method can flexibly adjust the bolt prestress according to the real-time changes of the surrounding rock, avoiding over-reinforcement or under-reinforcement. Compared with traditional reinforcement methods, it reduces unnecessary material and labor inputs and effectively reduces the construction cost;

[0029] In summary, the present invention realizes benefits such as improving the safety and durability of tunnel construction, reducing the construction cost, and enhancing the construction efficiency and accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A flowchart of an adaptive three-dimensional intersection tunnel surrounding rock reinforcement method is given;

[0031] Figure 2 A side view of an adjustable bolt is shown;

[0032] Figure 3 is Figure 2 An enlarged schematic view of the position M in

[0033] Figure 4 is Figure 2 A schematic view of the internal structure of the position M in

[0034] Figure 5 is Figure 4 A partially enlarged schematic view of the position N in

[0035] Figure 6 is Figure 5 A partially enlarged schematic view of the position P in

[0036] Reference numerals:

[0037] 1, anchor rod body; 2, first backing plate; 3, second backing plate; 4, washer; 5, nut; 201, conical groove; 202, annular block; 203, water storage tank; 204, compression spring; 205, piston plate; 206, expansion channel; 207, drainage channel; 208, limiting groove; 209, tension spring; 210, limiting block; 211, piston block; 212, fuse. Detailed implementation manners

[0038] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention.

[0039] Generally, the components of the embodiments of the present invention described and shown in the accompanying drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents the selected embodiments of the present invention.

[0040] Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0041] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0042] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] Embodiment

[0044] As Figures 1 to 6 shown, an adaptive stereoscopic intersection tunnel surrounding rock reinforcement method proposed by the present invention includes the following steps:

[0045] Step 1: Geological exploration and reinforcement plan design

[0046] Conduct a detailed exploration of the geological conditions in the tunnel area, and design a reinforcement plan according to the geological exploration results. Geological exploration, as the foundation of tunnel engineering design and construction, is generally divided into the preliminary exploration stage and the detailed survey stage.

[0047] Preliminary exploration stage: Focus on investigating the topographic, geological structure, lithology, faults, weathered and fractured zones and other geological and geomorphic conditions in the route selection area, and provide basic data such as regional topography and geology for engineering comparison. By collecting regional geological maps, satellite images and conducting on-site geological surveys, comprehensively master the regional geological background.

[0048] Detailed survey stage: Mainly solve the specific engineering geological problems in design and construction. Use technologies such as ground penetrating radar and core drilling to draw the geological longitudinal profile along the tunnel axis. Through the analysis of the core, determine the rock layers that will be encountered after the tunnel excavation, especially the specific positions, properties and widths of the weak rock layers. Use a method combining numerical simulation and on-site monitoring to determine different stability segments of the surrounding rock and the possible gushing areas of groundwater and harmful gases, etc. At the same time, according to the rock mass stability degree and other engineering geological conditions, put forward suggestions on the tunneling method, such as using the CD method or the CRD method for excavation in the areas with poor stability.

[0049] Then, design a scientific and reasonable reinforcement plan according to the comprehensive and accurate geological exploration results. This plan covers the selection of reinforcement methods, the selection of reinforcement materials, the sequence of reinforcement construction, etc. For example, for weak surrounding rock, give priority to the combination of grouting reinforcement and bolt support, and select appropriate grouting materials and bolt types according to the specific characteristics of the surrounding rock.

[0050] Step 2: Reinforcement operation before tunnel excavation

[0051] Before tunnel excavation, grout is injected into the surrounding rock through grouting holes, and adjustable bolts are installed along the excavation contour line with a preset external insertion angle towards the front of the excavation face. The adjustable bolt includes an anchoring main component, an adjustable anchoring assembly, and an expansion induction mechanism. The anchoring main component is used to strengthen the strength of the surrounding rock; the adjustable anchoring assembly is used to secondarily strengthen the strength of the surrounding rock based on the anchoring main component; the expansion induction mechanism is used to induce the operation of the adjustable anchoring assembly based on a control signal.

[0052] After determining the reinforcement plan, a drilling machine is used to drill holes in the tunnel wall according to the preset positions and angles of the grouting holes. After drilling is completed, the holes are thoroughly cleaned with high-pressure water or compressed air to ensure that there are no sundries in the holes, providing guarantee for the grouting effect. The prepared grout is injected into the drilled holes, and the grouting pressure is adjusted according to the geological conditions and design requirements, usually between 2 - 5 MPa. A certain pressure needs to be maintained during the grouting process to make the grout fully fill the voids. After grouting, the grouting effect is evaluated by detection means such as geological radar and acoustic wave testing, such as the grout diffusion range and consolidation strength. According to the evaluation results, supplementary grouting is carried out for the grouting holes that do not meet the requirements.

[0053] Then, holes are drilled in the surrounding rock to be reinforced along the excavation contour line with a preset external insertion angle towards the front of the excavation face.

[0054] Anchoring main component: It includes a bolt rod body 1. A nut 5 and a first backing plate 2 are arranged at the left end of the bolt rod body 1. The nut 5 is threadedly connected to the bolt rod body 1, and the bolt rod body 1 passes through the first backing plate 2 and is slidably matched with the first backing plate 2.

[0055] Adjustable anchoring assembly: It includes a second backing plate 3. The second backing plate 3 is located between the nut 5 and the first backing plate 2. The bolt rod body 1 passes through the second backing plate 3 and is slidably matched with the second backing plate 3. The first backing plate 2 and the second backing plate 3 are engaged with each other. The first backing plate 2 and the second backing plate 3 are connected by a simple mortise and tenon method, that is, a tenon is welded and fixed on the left side of the first backing plate 2, and a mortise groove is opened on the second backing plate 3. The mortise groove is opened along the length direction of the bolt rod body 1, facilitating relative sliding between the first backing plate 2 and the second backing plate 3. In this embodiment, a washer 4 is arranged between the second backing plate 3 and the nut 5. The bolt rod body 1 passes through the washer 4 and is slidably matched with the washer 4. The washer 4 can disperse the pressure of the nut 5 on the second backing plate 3, preventing the second backing plate 3 from being damaged due to excessive local pressure.

[0056] Expansion induction mechanism: It includes a conical groove 201 opened on either side of the contact surface between the first backing plate 2 and the second backing plate 3. In this embodiment, the conical groove 201 is opened on the left side of the first backing plate 2. The conical groove 201 is an annular groove, and its cross-section is two symmetrical triangles. An annular block 202 is placed in the conical groove 201, and the side walls of the annular block 202 are in contact with the inner wall of the conical groove 201 and the first backing plate 2 respectively. The cross-section of the annular block 202 is two circles, and the side walls of the annular block 202 are tangent to the inner wall of the conical groove 201 and the right side of the second backing plate 3 respectively. An expansion material is placed between the annular block 202 and the conical groove 201. In this embodiment, the expansion material is a mixture of cement and an expansion agent. A water storage tank 203 is opened in the first backing plate 2. The water storage tank 203 is also an annular structure, and the water storage tank 203 is communicated with the conical groove 201. A sealing component is provided at the connection between the water storage tank 203 and the conical groove 201 for temporarily sealing the water storage tank 203 and the conical groove 201.

[0057] An anchoring component is provided at the tail (i.e., the left end) of the bolt body 1. The anchoring component includes a nut 5, a first backing plate 2 and a second backing plate 3. The nut 5 is threadedly connected to the tail of the bolt body 1. In this embodiment, a washer 4 is also placed between the nut 5 and the second backing plate 3. The washer 4 disperses the pressure of the nut 5 on the second backing plate 3 to prevent the second backing plate 3 from being damaged due to excessive local pressure. Both the first backing plate 2 and the second backing plate 3 are slidably fitted with the bolt body 1. The first backing plate 2 and the second backing plate 3 are engaged with each other and connected by a mortise and tenon method. A tenon is welded and fixed on the left side of the first backing plate 2, and a mortise is opened on the second backing plate 3 to facilitate the relative sliding of the two. A conical groove 201 is opened on the left side of the first backing plate 2. The conical groove 201 is an annular groove, and its cross-section is two symmetrical triangles. An annular block 202 is placed in the conical groove 201, and the side walls of the annular block 202 are in contact with the inner wall of the conical groove 201 and the first backing plate 2 respectively. The side walls of the annular block 202 are tangent to the inner wall of the conical groove 201 and the right side of the second backing plate 3 respectively. An expansion material is placed between the annular block 202 and the conical groove 201. In this embodiment, it is a mixture of cement and an expansion agent. A water storage tank 203 is opened in the first backing plate 2. The water storage tank 203 is an annular structure, and the water storage tank 203 is communicated with the conical groove 201. A sealing component is provided at the connection between the water storage tank 203 and the conical groove 201 for temporarily sealing the water storage tank 203 and the conical groove 201.

[0058] Sealing component: Refer to the attached Figure 5 and the attached Figure 6As shown in the figure, it includes a limit block 210 and a piston block 211. An expansion channel 206 and a drainage channel 207 are successively communicated between the conical groove 201 and the water storage tank 203. The cross-sectional area of the expansion channel 206 is larger than that of the drainage channel 207. The two ends of the cross-section of the expansion channel 206 are trapezoidal structures, which facilitate the piston block 211 to slide from the drainage channel 207 into the expansion channel 206. The piston block 211 is slidably matched with the drainage channel 207. The top of the drainage channel 207 is communicated with a limit groove 208. The limit block 210 is slidably matched with the limit groove 208. A tension spring 209 is arranged between the limit block 210 and the limit groove 208. The two ends of the tension spring 209 are respectively welded and fixed to the top of the limit block 210 and the top wall of the limit groove 208. The bottom of the limit block 210 extends into the drainage channel 207. A fuse 212 is welded and fixed to the bottom of the limit block 210. The other end of the fuse 212 is welded and fixed to the inner wall of the drainage channel 207. The fuse 212 is signal-connected to a control circuit module. Wires are evenly arranged in the limit block 210 and the first backing plate 2. The control module includes a signal receiving unit (wireless communication chip (such as Zigbee / LoRa module), signal decoder, receiving control instructions issued by the data analysis platform, parsing the target bolt rod body ID and trigger command), a processing unit (microcontroller (MCU)-memory (storing the bolt rod body 1 number and trigger logic)), a power supply (power supply), a trigger execution unit (high-current pulse circuit, fuse melting electrode, status feedback sensor, generating an instantaneous large current to melt the fuse 212, and at the same time detecting the melting state and transmitting a confirmation signal back), and a protection structure (waterproof and sealed housing (IP67 standard), seismic buffer layer, ensuring the reliability of electronic components in a humid and vibrating environment). The high-current pulse circuit is connected to both ends of the fuse 212 through wires.

[0059] A water pressure boosting component is arranged in the water storage tank 203. Combined with the attached Figure 5 As shown in the figure, the water pressure boosting component includes a compression spring 204 and a piston plate 205. The piston plate 205 is slidably matched with the water storage tank 203. The two ends of the compression spring 204 are respectively welded and fixed to the piston plate 205 and the inner wall of the water storage tank 203. The elastic force of the compression spring 204 is used to apply pressure to the water in the water storage tank 203 to ensure that sufficient water pressure can be provided when triggered.

[0060] Anchoring installation process: Insert the bolt rod body 1 of the adjustable bolt into the drilled hole, and ensure that the anchor head part of the bolt rod body 1 is in close contact with the surrounding rock. Then install the first backing plate 2 and the second backing plate 3 at the tail of the bolt rod body 1, put in the washer 4, and finally tighten the first backing plate 2, the second backing plate 3 and the washer 4 through the nut 5.

[0061] Applying prestress: Using installation machinery or special tools to apply prestress to the anchor rod body 1, it produces a certain tensile deformation, thereby increasing the friction between the anchor rod body 1 and the surrounding rock. The magnitude of the prestress is determined according to the properties of the surrounding rock and design requirements, and is generally between 50-150kN.

[0062] Grouting anchoring: Inject slurry (such as cement slurry, resin slurry, etc.) into the anchor hole to make the anchor rod body 1 tightly combined with the surrounding rock. After the grouting is completed, the adjustable anchor rod is pre-tightened to ensure that it reaches the pre-tightening force required by the design. The position and angle of the anchor rod body 1 are fine-tuned according to the actual situation to meet the construction requirements.

[0063] Maintenance: After the slurry solidifies, necessary maintenance work is carried out to ensure the reinforcement effect of the adjustable anchor. The maintenance time is determined according to the type of slurry and environmental conditions, generally 7-14 days.

[0064] Step 3: Sensor installation and IoT data transmission system construction

[0065] Install sensors at key locations in the tunnel construction area and build an IoT data transmission system. The steps to build the IoT data transmission system are as follows:

[0066] Sensor selection: Select the sensor type based on the tunnel’s design parameters and construction requirements.

[0067] Sensor installation: Sensors are installed at key locations in the tunnel construction area, including the arch, sidewall, floor and excavation surface. Sensors include displacement sensors, pressure sensors and temperature sensors. The displacement sensor can be a laser displacement meter, the pressure sensor can be a vibrating wire pressure gauge, and the temperature sensor can be a thermocouple thermometer.

[0068] Hardware device selection: Select IoT hardware devices, such as sensor nodes, gateways, routers and other hardware devices. In this embodiment, sensor nodes are deployed.

[0069] Network connection and protocol selection: According to the environmental conditions and data transmission requirements of the tunnel construction area, select the network connection method (such as Wi-Fi, Bluetooth, Zigbee, LoRaWAN and other wireless technologies) and data transmission protocol (such as MQTT, CoAP, etc.) to achieve data transmission between sensor nodes and gateways. In areas with more signal obstruction, LoRaWAN technology is preferred to ensure the stability of data transmission.

[0070] Data management platform construction: Build an IoT data management platform to receive, store and process sensor data. The platform has functions such as real-time data analysis, historical data query, and abnormal alarm, supporting intelligent monitoring and management of tunnels.

[0071] Step Four: Establishment of Data Analysis Platform and Construction of 3D Surrounding Rock Strength Distribution Map

[0072] Establish a data analysis platform to conduct real-time analysis and processing of sensor data, and construct a 3D surrounding rock strength distribution map. The construction steps of the 3D surrounding rock strength distribution map are as follows:

[0073] Data Acquisition: Obtain the data output by the sensors in real time.

[0074] Data Preprocessing: Preprocess the acquired data, including data cleaning, normalization, etc. Data cleaning improves data quality by removing outliers and duplicate values.

[0075] Feature Extraction: Extract the key features representing the state of the surrounding rock from the preprocessed data. The key features include displacement, pressure value, strain value, and temperature change rate.

[0076] 3D Model Establishment: Use 3D modeling tools, combined with the design parameters and construction requirements of the tunnel, to establish a 3D model of the tunnel. In the 3D model, combine the sensor layout positions and the collected data with the actual geological conditions for refined modeling.

[0077] Distribution Map Drawing: Based on the extracted key features and the 3D model, draw a 3D surrounding rock strength distribution map. In the 3D surrounding rock strength distribution map, use different colors or grayscales to represent different strength levels of the surrounding rock. For example, red represents the area with lower strength, and green represents the area with higher strength.

[0078] Step Five: Adaptive Reinforcement Control and Prediction of Surrounding Rock Change Trend

[0079] Based on the 3D surrounding rock strength distribution map, obtain the areas that need to be strengthened with support, and control the adjustable bolts in these areas for reinforcement through the built IoT data management platform, and adjust the prestress of the bolt body 1 to adapt to the changes of the surrounding rock.

[0080] By sending a signal to the control circuit, when the control circuit receives the start signal, the current rapidly increases and burns out the fuse 212. Immediately, the limit block 210 loses its restraint and is pulled back into the limit groove 208 by the tension spring 209, releasing the restriction on the piston block 211, enabling the piston block 211 to immediately slide into the expansion channel 206 along the drainage channel 207 under the positive pressure in the water storage tank 203, and finally mix with the cement and expander in the conical groove 201. After the cement, expander, and water are mixed, a chemical reaction occurs and pushes the annular block 202 outwards, thereby increasing the pressure between the first backing plate 2 and the second backing plate 3, so as to achieve the secondary tension of the bolt body 1.

[0081] In addition, it also includes establishing a prediction model for the change trend of surrounding rock. Obtain the data collected by sensors, clean the collected raw data, remove outliers, missing values, etc., to ensure data quality. Perform normalization processing on the collected data. According to the type and distribution characteristics of the data, select a suitable normalization method (such as min-max normalization, Z-score standardization, etc.) to convert the data into a unified scale range. Divide the normalized data into a training set and a test set. Usually, the training set accounts for 70% - 80%, and the test set accounts for 20% - 30%. According to the complexity and non-linearity characteristics of the surrounding rock deformation, select a model algorithm (such as support vector machine (SVM), random forest, neural network (such as LSTM, GRU, etc.)). Use the training set data to train the model, adjust the model parameters to minimize the prediction error, and the cross-validation method can be used to optimize the model parameters. Use the test set data to verify the model, evaluate the prediction accuracy and generalization ability of the model, and obtain a prediction model for the change trend of surrounding rock. Integrate the trained prediction model for the change trend of surrounding rock into the Internet of Things data management platform to achieve real-time monitoring and prediction. Input the real-time collected data into the trained prediction model for the change trend of surrounding rock to predict the future deformation trend of the surrounding rock. According to the prediction result, set an early warning threshold. When the predicted value exceeds the threshold, trigger the early warning mechanism and notify the construction personnel in time to take corresponding measures.

[0082] The above specific embodiments are merely an optional embodiment of the present invention. Based on the technical solution of the present invention and the relevant inspirations of the above embodiments, those skilled in the art can make various alternative improvements and combinations to the above specific embodiments.

Claims

1. An adaptive method for reinforcing surrounding rock of a three-dimensional interchange tunnel, characterized in that, It includes the following steps: Step 1: Conduct a detailed geological survey of the area where the tunnel is located, and design a reinforcement plan based on the geological survey results; Step 2: Before tunnel excavation, inject slurry into the surrounding rock through grouting holes, and install adjustable anchor rods along the excavation contour line at a preset outward inclination angle towards the front of the excavation face; The adjustable anchor rod includes an anchoring main body component, an adjustable anchoring component, and an expansion induction mechanism; The anchoring main body component is used to strengthen the strength of the surrounding rock; The adjustable anchoring component is used to perform secondary strengthening of the surrounding rock strength based on the anchoring main body component; The expansion induction mechanism is used to induce the operation of the adjustable anchoring component based on a control signal; Step 3: Install sensors at key positions in the tunnel construction area, and build an Internet of Things data transmission system; Step 4: Establish a data analysis platform, perform real-time analysis and processing of sensor data, and establish a three-dimensional surrounding rock strength distribution map; Step 5: Based on the three-dimensional surrounding rock strength distribution map, obtain the area that needs to be strengthened in support, generate a control signal and send it to the expansion induction mechanism in this area for secondary reinforcement.

2. The adaptive three-dimensional intersection tunnel surrounding rock reinforcement method according to claim 1, wherein The steps for building the Internet of Things data transmission system include: Select the type of sensor according to the design parameters and construction requirements of the tunnel; Install sensors at key positions in the tunnel construction area; Select Internet of Things hardware devices and deploy sensor nodes; According to the environmental conditions and data transmission requirements in the tunnel construction area, select the network connection method and data transmission protocol; Build an Internet of Things data management platform to receive, store, and process sensor data.

3. The self-adaptive stereoscopic intersection tunnel surrounding rock reinforcement method according to claim 2, wherein, The key positions include the crown, side walls, floor, and excavation face.

4. The adaptive stereoscopic intersection tunnel surrounding rock reinforcement method according to claim 3, characterized in that, The sensors include displacement sensors, pressure sensors, and temperature sensors.

5. An adaptive method for reinforcing surrounding rock of a three-dimensional interchange tunnel according to claim 4, characterized in that, The steps for constructing the three-dimensional surrounding rock strength distribution map include: Real-time obtain the data output by the sensors; Preprocess the obtained data; Extract the key features representing the state of the surrounding rock from the preprocessed data; Use three-dimensional modeling tools, combined with the design parameters and construction requirements of the tunnel, to establish a three-dimensional model of the tunnel; In the three-dimensional model, combine the sensor layout positions and the collected data with the actual geological conditions for refined modeling; Based on the extracted key features and the three-dimensional model, draw a three-dimensional surrounding rock strength distribution map; In the three-dimensional surrounding rock strength distribution map, use different colors or grayscales to represent different strength grades of the surrounding rock.

6. The adaptive three-dimensional intersection tunnel surrounding rock reinforcement method according to claim 5, characterized in that, The key features include displacement, pressure value, strain value, and temperature change rate.

7. An adaptive three-dimensional intersection tunnel surrounding rock reinforcement method according to claim 6, characterized in that, It also includes establishing a prediction model for the change trend of the surrounding rock; Obtain the data collected by the sensors; Perform normalization processing on the collected data and divide it into a training set and a test set; According to the complexity and nonlinear characteristics of the surrounding rock deformation, select a model algorithm; Use the training set data to train the model and adjust the model parameters to minimize the prediction error; Use the test set data to verify the model, evaluate the prediction accuracy and generalization ability of the model, and obtain a prediction model for the change trend of the surrounding rock; Input the real-time collected data into the trained prediction model for the change trend of the surrounding rock to predict the future deformation trend of the surrounding rock.

8. An adaptive method for reinforcing surrounding rock of a three-dimensional interchange tunnel according to claim 7, characterized in that The anchoring main body component includes an anchor rod body (1); one end of the anchor rod body (1) is provided with a nut (5) and a first backing plate (2), the nut (5) is threadedly connected to the anchor rod body (1), and the anchor rod body (1) penetrates through the first backing plate (2) and is in sliding fit with the first backing plate (2); The adjustable anchoring assembly includes a second backing plate (3), the second backing plate (3) is located between the nut (5) and the first backing plate (2), the anchor rod body (1) penetrates through the second backing plate (3) and is in sliding fit with the second backing plate (3), and the first backing plate (2) and the second backing plate (3) are engaged with each other; a washer (4) is arranged between the second backing plate (3) and the nut (5), and the anchor rod body (1) penetrates through the washer (4) and is in sliding fit with the washer (4); The expansion induction mechanism includes a conical groove (201) opened on any one side close to the contact surface of the first backing plate (2) and the second backing plate (3), an annular block (202) is placed in the conical groove (201), the side walls of the annular block (202) are respectively in contact with the inner wall of the conical groove (201) and the first backing plate (2), and an expansion material is placed between the annular block (202) and the conical groove (201); a water storage tank (203) is arranged in the first backing plate (2), and the water storage tank (203) is communicated with the conical groove (201); a closing assembly is arranged at the communication position between the water storage tank (203) and the conical groove (201) for temporarily blocking the water storage tank (203) and the conical groove (201); a water pressure boosting assembly is arranged in the water storage tank (203).

9. An adaptive method for reinforcing surrounding rock of a three-dimensional interchange tunnel according to claim 8, characterized in that, The water pressure boosting assembly includes a compression spring (204) and a piston plate (205); the piston plate (205) is in sliding fit with the water storage tank (203), and both ends of the compression spring (204) are fixedly connected to the inner wall of the water storage tank (203) and the piston plate (205) respectively.

10. The method for reinforcing surrounding rock of an adaptive interchange tunnel according to claim 9, characterized in that, The closing assembly includes a limiting block (210) and a piston block (211); an expansion channel (206) and a drainage channel (207) are sequentially communicated between the conical groove (201) and the water storage tank (203), the cross-sectional area of the expansion channel (206) is larger than that of the drainage channel (207), and the piston block (211) is in sliding fit with the drainage channel (207); a limiting groove (208) is communicated with one side of the drainage channel (207), the limiting block (210) is in sliding fit with the limiting groove (208), a tension spring (209) is arranged between the limiting block (210) and the limiting groove (208), one end of the limiting block (210) away from the tension spring (209) extends into the drainage channel (207), a fuse (212) is arranged at one end of the limiting block (210) away from the tension spring (209), the other end of the fuse (212) is fixedly connected to the inner wall of the drainage channel (207), and the fuse (212) is signal-connected to a control module, and the control module is used for receiving a control signal to control the fusing of the fuse (212).

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