Rapid construction method and system for lower step with inverted arch of horizontal rock stratum large-section tunnel

Abstract

The invention relates to the technical field of tunnel construction, and discloses a rapid construction method and system for a lower step with an inverted arch of a horizontal rock stratum large-section tunnel, and the method comprises the steps: constructing a three-dimensional geological modeling system to carry out advanced geological forecast on a tunnel construction region; the three-arm drill jumbo is used for conducting self-positioning, geological self-adaptive intelligent hole arrangement, dynamic optimization of drilling parameters and dynamic allocation of drilling tasks through three-arm cooperative control; calculating the vector deviation between the actual excavation contour and the design contour; marking a preferential injection area based on a three-dimensional laser point cloud technology, and dynamically adjusting an injection track and thickness according to back break data; a multifunctional drilling and grouting integrated trolley is adopted for implementing pipe shed supporting, advanced small guide pipe reinforcement, pre-grouting reinforcement and anchor rod reinforcement; the main mechanical arm assists the trolley in drilling and laser scanning acceptance inspection of the feet-lock bolt; re-spraying to the designed thickness by adopting a wet spraying manipulator; the problems that an existing tunnel lower step inverted arch construction method is low in construction efficiency and large in construction risk are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel construction, and in particular to a method and system for quickly constructing a lower step with an inverted arch in a large-section tunnel in a horizontal rock stratum. Background Art

[0002] Horizontal rock strata typically have well-developed stratification, low rock mass strength, and poor surrounding rock stability. During tunnel excavation, the horizontal rock strata in the arch are prone to loosening, breaking, and falling blocks due to directional weak surfaces and stress redistribution, leading to arch collapse and overexcavation, posing a high safety risk. After the invert is excavated, unloading and shale expansion may cause a bottom bulge effect, causing the invert and fill layer to bulge, affecting future operations. In addition, the initial support after excavation of the horizontal rock strata in the arch is subject to significant pressure. If the shotcrete does not meet the strength requirements, it may cause excessive deformation of the initial support, concrete shedding, and bending or twisting of the grid steel frame, further threatening tunnel stability. Large-section tunnels, due to their large excavation spans and complex construction spaces, further increase the construction difficulty. Existing tunnel construction methods often encounter the following problems when working with horizontal rock formations and large-cross-section tunnels: 1. Poor surrounding rock stability: Horizontal rock formations have a distinct bedding structure, making rock mass susceptible to slippage or collapse along bedding planes. This is particularly true in large-cross-section tunnels, where the stress distribution in the surrounding rock after excavation is complex, easily leading to localized collapse or widespread instability, increasing construction risks. 2. Inaccurate geological forecasts: The geological conditions in horizontal rock formations are complex, making it difficult for existing geological forecasting techniques to accurately predict the characteristics of the rock formation ahead and the stability of the surrounding rock. This leads to frequent unexpected geological problems during construction, increasing construction uncertainty. 3. Low construction efficiency: Traditional construction methods are slow, especially in large-cross-section tunnels. Due to the large excavation spans and complex construction procedures, parallel operations between upper and lower steps are difficult to achieve, resulting in extended construction periods. 4. High reliance on manual labor: Existing construction methods still rely heavily on manual labor for drilling, blasting, and support operations. This is particularly true in horizontal rock formations, where manual labor accuracy and efficiency are difficult to guarantee, increasing construction risks and making quality control more difficult. 5. Problems of under-excavation and over-excavation: In the construction of large-section tunnels, due to the large excavation span and complex deformation of the surrounding rock, under-excavation or over-excavation is prone to occur. Under-excavation will make subsequent support difficult, and over-excavation will increase the amount of concrete backfill, affecting the construction progress and cost. 6. Difficulty in support: The surrounding rock of horizontal rock formations has poor self-stabilization ability. Especially in large-section tunnels, the support structure bears a large load. Traditional support methods are difficult to effectively control the deformation of the surrounding rock, which can easily cause failure or local damage of the support structure. 7. Low degree of mechanization: Existing construction methods have a low degree of mechanization in under-excavation processing, support and other links. Especially in horizontal rock formations, they still rely on manual operation, making it difficult to achieve rapid construction, resulting in low construction efficiency. Therefore, there is an urgent need for a method that can realize the rapid construction of the lower step with an invert arch in large-section tunnels in horizontal rock formations to improve construction efficiency, reduce construction risks, and shorten the construction period. Summary of the Invention

[0003] The present invention provides a method and system for quickly constructing a lower step with an inverted arch in a large-section tunnel in a horizontal rock stratum, so as to solve the problems of low construction efficiency and high construction risk in the existing method for constructing a lower step with an inverted arch in a tunnel.

[0004] In order to achieve the above object, the present invention is implemented through the following technical solutions: In a first aspect, the present invention provides a method for rapidly constructing a lower step with an inverted arch in a large-section tunnel in a horizontal rock stratum, comprising: S1. Build a 3D geological modeling system by integrating multimodal intelligent perception technology and spatiotemporal alignment of heterogeneous sensor data. This system, combined with a multi-source data fusion algorithm and a dynamic confidence weighting algorithm, generates a millimeter-level precision geological model to provide advanced geological forecasts for the tunnel construction area. S2. Use a three-arm drilling rig for autonomous positioning, geologically adaptive intelligent hole placement, dynamic optimization of drilling parameters, and three-arm collaborative control to dynamically allocate drilling tasks. The drilling order for the drilling tasks is: bottom plate holes first, then peripheral holes, and the tasks are completed in a top-to-bottom and left-to-right order. S3, based on multi-source data fusion, acquires the three-dimensional coordinate data, contour geometric deviation, and deformation of the tunnel section in real time. A deep learning algorithm is used to calculate the vector deviation between the actual excavation contour and the designed contour. Automatic warnings are triggered when the underexcavation deformation exceeds a threshold for three consecutive monitoring cycles. S4: Use a six-degree-of-freedom robotic arm to initially spray concrete to seal the upper step face. Use 3D laser point cloud technology to mark priority spraying areas, and dynamically adjust the spraying trajectory and thickness based on overbreak and underbreak data. S5. Use a multifunctional drilling and grouting trolley to implement pipe roof support, advance small guide pipes, pre-grouting reinforcement and anchor reinforcement; S6: The main robotic arm automatically grabs the steel arch frame and completes the arch foot locking and connecting plate welding. The slave robotic arm installs the arch foot, and the auxiliary trolley performs the locking foot anchor drilling and laser scanning acceptance. S7. Dynamically adjust the re-spraying area according to the initial support deformation data, and use a wet spraying robot to re-spray to the designed thickness.

[0005] Optionally, in S1, the multimodal intelligent sensing technology includes: laser point cloud technology, distributed optical fiber sensing technology, array geological radar technology, borehole resistivity CT technology, construction machinery vibration spectrum technology, and drone infrared thermal imaging technology; Laser point cloud technology is used to obtain millimeter-level surface morphology, distributed fiber optic sensing technology is used to obtain dynamic data of strain field and temperature field, array geological radar technology is used to obtain three-dimensional distribution of dielectric constant, borehole resistivity CT technology is used to obtain fracture network imaging, construction machinery vibration spectrum technology is used to invert rock hardness, and drone infrared thermal imaging technology is used to locate aquifers.

[0006] Optionally, in S2, using a three-arm drilling rig for autonomous positioning includes: deploying anchor points between the rig and the tunnel surrounding rock, and using a laser radar to calculate the distance between the rig and the anchor points, wherein the distance between the rig and the anchor points is calculated in a manner that satisfies the following relationship: ; Where, d is the distance between the trolley and the anchor point, c is the speed of light, t 总 is the round trip time of the electrical signal, t 延误 Processing delay time for anchor points; The UWB positioning module on the trolley performs two-way ranging with the anchor point to obtain the geographical location information of the anchor point. The geographical location information is used as the absolute position information, and the distance between the trolley and the anchor point is used as the relative posture information and input into the on-board central processor; The on-board central processing unit fuses the relative posture information provided by the lidar with the absolute position information provided by the ultra-wideband positioning module, and outputs the position of the trolley for autonomous positioning. Geologically adaptive intelligent hole layout includes: based on the three-dimensional geological model, using computer image processing algorithms to automatically identify and extract key joint surfaces, and output the normal vector of each joint surface; Based on the preset engineering objectives, a geometric optimization algorithm is applied to calculate the angle between the borehole axis direction vector and the extracted key joint surface normal vector. The optimal direction of each borehole is calculated based on the designed hole depth and hole mouth position, generating the final digital, work surface-adaptive hole layout plan. The dynamic optimization of drilling parameters involves installing sensors on the drill rig of each drill boom to measure the drill rod propulsion speed, rotational torque, and drill tool wear in real time. These sensors are then output to the onboard central processor in the form of electrical signals. Fuzzy logic is used to control the dynamic optimization algorithm to maximize the overall drilling efficiency. The pulse width modulation signal of the drill boom is adjusted in real time. The calculation method of the pulse width modulation signal of the drill boom movement satisfies the following relationship: ; Where, V is the pulse width modulation signal of the drill arm action, i 目标 is the target joint angle of the drill arm, i反馈 is the drill arm angle fed back by the sensor, i 误差 is the deviation between the target angle and the actual angle during the operation of the drill arm. t is the electrical signal output time, k p 、k d is the adjustment factor; The three-arm collaborative control dynamic allocation of drilling tasks includes: running a multi-agent task allocation calculation algorithm in the vehicle-mounted central processing unit, decomposing the drilling tasks of the entire working surface into independent drilling work units, and establishing a task queue for all work units to avoid collisions between robotic arms. The optimal allocation plan calculated for the global optimization goal is converted into a specific action instruction sequence and transmitted to the local controller of each drilling arm to realize the three-arm collaborative control dynamic allocation of drilling tasks.

[0007] Optionally, in S3, the under-digging processing method is: An excavator with a breaker hammer is used to process the broken rock mass and the first undercut part, and an arch-mounted trolley is used to process the second undercut part. The undercut range of the first undercut part is larger than the undercut range of the second undercut part, and the undercut deformation threshold is: 2mm.

[0008] Optionally, in S4, the condition for marking the priority injection area is: the sudden change value of the point cloud curvature is greater than 0.25m -1 .

[0009] Optionally, in S4, the initial spraying sequence is carried out from bottom to top, the designed thickness is 10 cm and the spraying is carried out twice: the first layer has a sealing thickness of 5 cm, and the second layer is sprayed after final setting with a thickness of 5 cm.

[0010] Optionally, in S5, the advance support configuration is: a middle pipe rack with a diameter of 89 mm and an advance small guide tube with a diameter of 42 mm are set within the 140° range of the tunnel arch, supplemented by advance grouting, and the length of the advance small guide tube is 5.5 m, and the circumferential spacing is not more than 0.3 m.

[0011] Optionally, in S5, the advance pre-reinforcement method includes at least one of: self-propelled anchor reinforcement, fiber anchor reinforcement, surface grouting reinforcement, in-tunnel advance grouting reinforcement, and in-tunnel curtain grouting reinforcement.

[0012] 9. The rapid construction method for a lower step with an inverted arch in a large-section tunnel in a horizontal rock stratum according to claim 1, characterized in that in S7, the wet spraying manipulator is equipped with an adaptive nozzle with stepless aperture adjustment, and the nozzle diameter is 10-30 mm; The order of re-spraying is: proceed continuously from bottom to top in layers and pieces; after the re-spraying of the lower step is completed, the upper step should be re-sprayed immediately.

[0013] In a second aspect, an embodiment of the present application provides a rapid construction system for a lower step with an inverted arch in a large-section tunnel in a horizontal rock formation, comprising a processor and a memory; Memory for storing computer programs; The processor is configured to implement any one of the method steps described in the first aspect when executing a program stored in the memory.

[0014] Beneficial effects: The rapid construction method of the lower step with an inverted arch in a large-section tunnel in a horizontal rock stratum provided by the present invention realizes parallel operation of the upper and lower steps by adopting a two-step three-step method, thereby reducing interference between working procedures, improving the continuity and coordination of construction, and significantly shortening the construction period. The use of multimodal intelligent sensing technology, a three-arm drilling rig, and three-dimensional laser point cloud technology reduces the risks of landslides, instability of surrounding rocks, and the like during construction. The use of a steel arch frame intelligent installation system and a wet spraying collaborative re-spraying system reduces reliance on manual operation, improves construction accuracy and efficiency, and reduces the risks caused by human operational errors. Measures such as initial spraying of concrete to seal the face, advance support, advance pre-reinforcement, and installation of arch frames are adopted to ensure the stability of the surrounding rock and prevent landslides and instability of surrounding rocks. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a flow chart of a rapid construction method for a lower step with an inverted arch in a large-section tunnel in a horizontal rock stratum according to a preferred embodiment of the present invention; Figure 2 A schematic diagram comparing the construction progress of the mechanical excavation method and the manual drilling and blasting method in a preferred embodiment of the present invention; Figure 3 A schematic diagram comparing the monitoring values ​​of arch subsidence and horizontal convergence of the mechanical excavation method and the manual drilling and blasting method provided in the preferred embodiment of the present invention. DETAILED DESCRIPTION

[0016] The following is a clear and complete description of the technical solutions of the present invention. It should be understood that the embodiments described are only a portion of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are intended to fall within the scope of protection of the present invention.

[0017] Unless otherwise defined, the technical or scientific terms used in the present invention shall have the usual meanings understood by persons of ordinary skill in the field to which the present invention belongs. The words "first", "second" and similar terms used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one" or "a" do not indicate a quantity limitation, but rather indicate the existence of at least one. Words such as "connected" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship also changes accordingly.

[0018] See Figure 1-3 The embodiment of the present application provides a rapid construction method for a lower step with an inverted arch in a large-section tunnel in a horizontal rock stratum, comprising the following steps: S1. Build a 3D geological modeling system by integrating multimodal intelligent perception technology and spatiotemporal alignment of heterogeneous sensor data. This system, combined with a multi-source data fusion algorithm and a dynamic confidence weighting algorithm, generates a millimeter-level precision geological model to provide advanced geological forecasts for the tunnel construction area. S2. Use a three-arm drilling rig for autonomous positioning, geologically adaptive intelligent hole placement, dynamic optimization of drilling parameters, and three-arm collaborative control to dynamically allocate drilling tasks. The drilling order for the drilling tasks is: bottom plate holes first, then peripheral holes, and the tasks are completed in a top-to-bottom and left-to-right order. S3, based on multi-source data fusion, acquires the three-dimensional coordinate data, contour geometric deviation, and deformation of the tunnel section in real time. A deep learning algorithm is used to calculate the vector deviation between the actual excavation contour and the designed contour. Automatic warnings are triggered when the underexcavation deformation exceeds a threshold for three consecutive monitoring cycles. S4: Use a six-degree-of-freedom robotic arm to initially spray concrete to seal the upper step face. Use 3D laser point cloud technology to mark priority spraying areas, and dynamically adjust the spraying trajectory and thickness based on overbreak and underbreak data. S5. Use a multifunctional drilling and grouting trolley to implement pipe roof support, advance small guide pipes, pre-grouting reinforcement and anchor reinforcement; S6: The main robotic arm automatically grabs the steel arch frame and completes the arch foot locking and connecting plate welding. The slave robotic arm installs the arch foot, and the auxiliary trolley performs the locking foot anchor drilling and laser scanning acceptance. S7. Dynamically adjust the re-spraying area according to the initial support deformation data, and use a wet spraying robot to re-spray to the designed thickness.

[0019] In the above embodiment, the method can be further refined into the following steps: Step 1: Through the integration of the following multimodal intelligent perception technologies: multimodal intelligent perception technologies are laser point cloud, distributed fiber optic sensing, array geological radar, borehole resistivity CT, construction machinery vibration spectrum, and drone infrared thermal imaging to obtain millimeter-level surface morphology, strain / temperature field dynamic data, three-dimensional distribution of dielectric constant, fracture network imaging, rock hardness inversion, and aquifer positioning, respectively. Combined with the spatiotemporal alignment technology of heterogeneous sensor data, a three-dimensional geological modeling system is constructed. Through multi-source data fusion algorithm and dynamic confidence weighting algorithm, a millimeter-level precision geological model is generated to conduct advanced geological forecasts for the tunnel construction area.

[0020] Step 2: The three-arm drilling rig uses dust-resistant laser radar to extract point cloud data of tunnel wall structure information. The electrical signal processing algorithm (point cloud filtering and intensity threshold segmentation) identifies and filters out noise points caused by dust particles. Anchor points are deployed between the rig and the tunnel surrounding rock, and the laser radar is used to calculate the distance between the rig and the anchor points. The calculation method of the distance between the rig and the anchor points satisfies the following relationship: ; Where, d is the distance between the trolley and the anchor point, c is the speed of light, t 总 is the round trip time of the electrical signal, t 延误 Handle delay time for anchor points.

[0021] The UWB positioning module on the trolley performs two-way ranging with the anchor point to obtain the geographical location information of the anchor point, which is used as the absolute position information and the distance between the trolley and the anchor point as the relative posture information to be output to the on-board central processor; The on-board central processing unit fuses the high-precision relative posture information of the trolley and the anchor point provided by the lidar with the absolute position information provided by the ultra-wideband positioning module, and outputs the position of the trolley for autonomous positioning. The fusion calculation includes: constructing a geographic coordinate system, determining the position of each anchor point in the geographic coordinate system based on the absolute position information, and determining the distance between the trolley and the anchor point based on the relative posture information, substituting the distance between the trolley and the anchor point into the geographic coordinate system, so that there is a position in the geographic coordinate system, and the distance from this position to each anchor point satisfies the distance between the trolley and the anchor point calculated by the relationship. At this time, this position is output as the position of the trolley, thereby achieving autonomous positioning.

[0022] Based on the three-dimensional geological model, computer image processing algorithms are used to automatically identify and extract key joint surfaces, and the normal vector of each joint surface is output. According to the preset engineering objectives (maximizing blasting effect, minimizing overbreak and underbreak, and optimizing rock anchor effect), a geometric optimization algorithm is applied to calculate the angle between the borehole axis direction vector and the extracted key joint surface normal vectors. After calculating the optimal direction vector of each borehole based on the principle of making the borehole axis intersect the main joint surfaces as perpendicularly as possible, the final digital, working face adaptive hole layout plan is generated based on the design parameters such as hole depth and hole mouth position.

[0023] Sensors are installed on the drill rig of each drill boom to measure the drill rod propulsion speed, rotational torque, and drill tool wear in real time. These are then output to the onboard central processor in the form of electrical signals. Fuzzy logic control and dynamic optimization algorithms are used to adjust the pulse width modulation signal of the drill boom in real time with the goal of maximizing the overall drilling efficiency. The pulse width modulation signal calculation method for the drill boom movement satisfies the following relationship: ; Where, V is the pulse width modulation signal of the drill arm action, i 目标 is the target joint angle of the drill arm, i 反馈 is the drill arm angle fed back by the sensor, i 误差 is the deviation between the target angle and the actual angle during the operation of the drill arm. t is the electrical signal output time, k p 、k d is the adjustment factor.

[0024] After the pulse-width modulation signal of the drill arm's motion is synchronously transmitted to the vehicle's central processing unit in the form of an electrical signal, a data fusion matrix is ​​constructed for the drill rod's propulsion speed, rotational torque, and drill tool wear. A multi-agent task allocation calculation algorithm is run on the vehicle's central processing unit, breaking down the entire face's drilling task (drill arm position, posture, and path planning) into independent drilling units. A task queue is established for all units, and the optimal allocation solution calculated with the global optimization goal of minimizing total operation time and the risk of robot arm collision is converted into a specific sequence of action instructions and transmitted to the local controller of each drill arm, enabling dynamic allocation of drilling tasks through coordinated control of the three arms. The front support mileage and drilling depth are confirmed, the drilling location is checked, and automatic drilling is performed using a multi-level wedge pattern, starting with the bottom plate eye, then the peripheral eye, from top to bottom, and from left to right.

[0025] Step 3: An intelligent tunnel underbreak monitoring, analysis, and early warning system based on multi-source data fusion determines the extent of underbreak in real time. High-precision laser rangefinders, an array of inclination sensors, and image recognition devices are deployed to acquire real-time 3D coordinate data, contour geometry deviation, deformation, and surface crack characteristics of the tunnel cross section. These features are used as inputs to carefully annotate the collected feature data, clarifying the vector deviation between the actual excavation contour and the designed contour for each data sample, as well as whether it is underbreak. The annotated data is divided into training, validation, and test sets. A PointCNN learning model is used for training. The model parameters are continuously adjusted through a backpropagation algorithm to output the vector deviation between the actual excavation contour and the designed contour. The PointCNN model output is then matched against a holographic 3D geological model using a point cloud. An automatic warning is triggered when the underbreak deformation exceeds a threshold (2 mm) for three consecutive monitoring cycles. In the event of underbreak, an excavator equipped with a breaker hammer can be used to address the surrounding broken rock and larger underbreak areas. For smaller underbreaks, an arch-mounted trolley can be used.

[0026] Step 4: After excavation, a six-degree-of-freedom robotic arm is used to precisely spray concrete to seal the upper step face. The three-dimensional laser point cloud technology is used to calculate the point cloud curvature mutation rate, which satisfies the following relationship: i =( k max- k min) / s ; Where, i is the curvature mutation rate, k max is the maximum curvature, k min is the minimum curvature, s is the distance between two test points.

[0027] And the point cloud curvature mutation value is greater than 0.25m -1 Marked as the priority spraying area, the spraying trajectory and spraying thickness are dynamically adjusted according to the over-excavation and under-excavation data. The spraying sequence is carried out from bottom to bottom, and the initial spraying thickness is designed to be 10cm, which is carried out in two times. After the first layer is finally set, the subsequent layer spraying is carried out, and the sealing thickness is 5cm each time. During the process, the small pits of local over-excavation are sprayed and leveled. The comparison between the mechanical excavation method and the manual drilling and blasting method in the embodiment is as follows: Figure 2 As shown in the figure, mechanical excavation can increase the cumulative excavation length, shorten the construction time under the same excavation length, and greatly improve the construction efficiency.

[0028] Step 5: Advanced support and pre-reinforcement. Advanced support is provided by installing a φ89 medium pipe shed and φ42 small pipes within a 140° radius of the arch, where φ represents the pipe diameter. This is supplemented by advanced grouting. The small pipes are 5.5m long and spaced no more than 0.3m apart around the perimeter. Pre-reinforcement utilizes self-propelled anchor bolts, fiber anchor bolts, surface grouting, in-tunnel advanced grouting, and in-tunnel curtain grouting.

[0029] Step 6: Based on the intelligent installation system for steel arch frames, the main robotic arm automatically grabs the steel arch frame and locks the arch feet and welds the connecting plates. The slave robotic arm installs the arch feet, the auxiliary trolley drills the locking foot anchor rods, and laser scanning is performed for acceptance.

[0030] Step 7: Use a wet spraying manipulator with a nozzle with a diameter of 10-30mm and an aperture adaptive nozzle that can be adjusted steplessly to spray continuously from bottom to top, layer by layer, slice by slice, and time by time until the designed thickness is reached. After the spraying of the lower step is completed, the upper step is supported in advance and the upper step is immediately sprayed to achieve parallel operation of the upper and lower steps in the support process. Figure 3 As shown in the figure, mechanical excavation can greatly reduce the cumulative deformation during the excavation process, improve construction safety and reduce construction risks.

[0031] The embodiment of the present application also provides a rapid construction system for a lower step with an inverted arch in a large-section tunnel in a horizontal rock formation, comprising a processor and a memory; Memory for storing computer programs; The processor is used to implement any method step of the method for quickly constructing the lower step with inverted arch of a large-section tunnel in a horizontal rock layer when executing the program stored in the memory.

[0032] The above-mentioned rapid construction system for the lower step with an inverted arch in a large-section tunnel in a horizontal rock stratum can realize the various embodiments of the above-mentioned rapid construction method for the lower step with an inverted arch in a large-section tunnel in a horizontal rock stratum, and can achieve the same beneficial effects, which will not be described here.

[0033] The above describes in detail the preferred embodiments of the present invention. It should be understood that those skilled in the art can make numerous modifications and variations based on the concepts of the present invention without inventive effort. Therefore, any technical solutions that can be derived by those skilled in the art through logical analysis, reasoning, or limited experimentation based on the concepts of the present invention and the prior art should be within the scope of protection defined by the claims.

Claims

1. A rapid construction method for a large-section tunnel with an inverted arch at the lower step in a horizontal rock stratum, characterized in that: include: S1. Build a 3D geological modeling system by integrating multimodal intelligent perception technology and spatiotemporal alignment of heterogeneous sensor data. This system, combined with a multi-source data fusion algorithm and a dynamic confidence weighting algorithm, generates a millimeter-level precision geological model to provide advanced geological forecasts for the tunnel construction area. S2. Use a three-arm drilling rig for autonomous positioning, geologically adaptive intelligent hole placement, dynamic optimization of drilling parameters, and three-arm collaborative control to dynamically allocate drilling tasks. The drilling order for the drilling tasks is: bottom plate holes first, then peripheral holes, and the tasks are completed in a top-to-bottom and left-to-right order. S3, based on multi-source data fusion, acquires the three-dimensional coordinate data, contour geometric deviation, and deformation of the tunnel section in real time. A deep learning algorithm is used to calculate the vector deviation between the actual excavation contour and the designed contour. Automatic warnings are triggered when the underexcavation deformation exceeds a threshold for three consecutive monitoring cycles. S4: Use a six-degree-of-freedom robotic arm to initially spray concrete to seal the upper step face. Use 3D laser point cloud technology to mark priority spraying areas, and dynamically adjust the spraying trajectory and thickness based on overbreak and underbreak data. S5. Use a multifunctional drilling and grouting trolley to implement pipe roof support, advance small guide pipes, pre-grouting reinforcement and anchor reinforcement; S6: The main robotic arm automatically grabs the steel arch frame and completes the arch foot locking and connecting plate welding. The slave robotic arm installs the arch foot, and the auxiliary trolley performs the locking foot anchor drilling and laser scanning acceptance. S7. Dynamically adjust the re-spraying area according to the initial support deformation data, and use a wet spraying robot to re-spray to the designed thickness.

2. The rapid construction method for a large-section tunnel with an inverted arch at the lower step in a horizontal rock layer according to claim 1 is characterized in that: In S1, the multimodal intelligent sensing technology includes: laser point cloud technology, distributed optical fiber sensing technology, array geological radar technology, borehole resistivity CT technology, construction machinery vibration spectrum technology, and drone infrared thermal imaging technology; Laser point cloud technology is used to obtain millimeter-level surface morphology, distributed fiber optic sensing technology is used to obtain dynamic data of strain field and temperature field, array geological radar technology is used to obtain three-dimensional distribution of dielectric constant, borehole resistivity CT technology is used to obtain fracture network imaging, construction machinery vibration spectrum technology is used to invert rock hardness, and drone infrared thermal imaging technology is used to locate aquifers.

3. The rapid construction method for a large-section tunnel with an inverted arch at the lower step in a horizontal rock layer according to claim 1 is characterized in that: In S2, autonomous positioning using a three-arm drilling rig includes: deploying anchor points between the rig and the tunnel surrounding rock, and calculating the distance between the rig and the anchor points using a laser radar. The calculation method of the distance between the rig and the anchor points satisfies the following relationship: ； Where, d is the distance between the trolley and the anchor point, c is the speed of light, t 总 is the round trip time of the electrical signal, t 延误 Processing delay time for anchor points; The UWB positioning module on the trolley performs two-way ranging with the anchor point to obtain the geographical location information of the anchor point. The geographical location information is used as the absolute position information, and the distance between the trolley and the anchor point is used as the relative posture information and input into the on-board central processor; The on-board central processing unit fuses the relative posture information provided by the lidar with the absolute position information provided by the ultra-wideband positioning module, and outputs the position of the trolley for autonomous positioning. Geologically adaptive intelligent hole layout includes: based on the three-dimensional geological model, using computer image processing algorithms to automatically identify and extract key joint surfaces, and output the normal vector of each joint surface; Based on the preset engineering objectives, a geometric optimization algorithm is applied to calculate the angle between the borehole axis direction vector and the extracted key joint surface normal vector. The optimal direction of each borehole is calculated based on the designed hole depth and hole mouth position, generating the final digital, work surface-adaptive hole layout plan. The dynamic optimization of drilling parameters involves installing sensors on the drill rig of each drill boom to measure the drill rod propulsion speed, rotational torque, and drill tool wear in real time. These sensors are then output to the onboard central processor in the form of electrical signals. Fuzzy logic is used to control the dynamic optimization algorithm to maximize the overall drilling efficiency. The pulse width modulation signal of the drill boom is adjusted in real time. The calculation method of the pulse width modulation signal of the drill boom movement satisfies the following relationship: ； Where, V is the pulse width modulation signal of the drill arm action, θ 目标 is the target joint angle of the drill arm, θ 反馈 is the drill arm angle fed back by the sensor, θ 误差 is the deviation between the target angle and the actual angle during the operation of the drill arm. t is the electrical signal output time, k p 、k d is the adjustment factor; The three-arm collaborative control dynamic allocation of drilling tasks includes: running a multi-agent task allocation calculation algorithm in the vehicle-mounted central processing unit, decomposing the drilling tasks of the entire working surface into independent drilling work units, and establishing a task queue for all work units to avoid collisions between robotic arms. The optimal allocation plan calculated for the global optimization goal is converted into a specific action instruction sequence and transmitted to the local controller of each drilling arm to realize the three-arm collaborative control dynamic allocation of drilling tasks.

4. The rapid construction method for a large-section tunnel with an inverted arch at the lower step in a horizontal rock layer according to claim 1 is characterized in that: In S3, the undercut processing method is: An excavator with a breaker hammer is used to process the broken rock mass and the first undercut part, and an arch-mounted trolley is used to process the second undercut part. The undercut range of the first undercut part is larger than the undercut range of the second undercut part, and the undercut deformation threshold is: 2mm.

5. The rapid construction method for a lower step with an inverted arch in a large-section horizontal rock tunnel according to claim 1 is characterized in that: In S4, the condition for marking the priority injection area is: the sudden change value of the point cloud curvature is greater than 0.25m -1 .

6. The rapid construction method for a large-section tunnel with an inverted arch at the lower step in a horizontal rock layer according to claim 1 is characterized in that: In the S4, the initial spraying sequence is carried out from bottom to top, the designed thickness is 10 cm and it is sprayed twice: the first layer has a sealing thickness of 5 cm, and the second layer is sprayed after final setting with a thickness of 5 cm.

7. The rapid construction method for a large-section tunnel with an inverted arch at the lower step in a horizontal rock layer according to claim 1 is characterized in that: In S5, the advanced support configuration is: a middle pipe shed with a diameter of 89 mm and an advanced small pipe with a diameter of 42 mm are set within the 140° range of the tunnel arch, supplemented by advanced grouting, and the length of the advanced small pipe is 5.5 m, and the circumferential spacing is not more than 0.3 m.

8. The rapid construction method for a lower step with an inverted arch in a large-section horizontal rock tunnel according to claim 1 is characterized in that: In S5, the advance pre-reinforcement method includes at least one of: self-propelled anchor reinforcement, fiber anchor reinforcement, surface grouting reinforcement, in-tunnel advance grouting reinforcement, and in-tunnel curtain grouting reinforcement.

9. The rapid construction method for a lower step with an inverted arch in a large-section horizontal rock tunnel according to claim 1, characterized in that: In S7, the wet spraying manipulator is equipped with an adaptive nozzle with stepless aperture adjustment, and the diameter of the nozzle is 10-30 mm; The order of re-spraying is: proceed continuously from bottom to top in layers and pieces; after the re-spraying of the lower step is completed, the upper step should be re-sprayed immediately.

10. A rapid construction system for a large-section tunnel with an inverted arch at the lower step in a horizontal rock formation, characterized in that: Including processor and memory; Memory for storing computer programs; A processor, configured to implement the method steps described in any one of claims 1 to 9 when executing a program stored in a memory.

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