Construction method and system for assisting in controlling over-break and under-break of tunnel through multifunctional heading machine

Abstract

The invention discloses a construction method and system for a multifunctional heading machine to assist in controlling over-break and under-break of a tunnel, and relates to the field of engineering construction.The method comprises the steps that design contour information and geological parameter information of a target tunnel are obtained; determining undercut contour design information corresponding to blasting forming based on the design contour information and the geological parameter information; determining blasting point position information and blasting explosive quantity information based on the undercut contour design information and the geological parameter information; after blasting is completed, the outline after blasting is scanned so as to obtain outline information after blasting; and controlling the multifunctional heading machine to finely trim and level the outline information after blasting so as to enable the actual outline information to be close to the designed outline information. A whole-process cooperation mechanism from differentiated blasting design, fine trimming target recognition, tunneling path optimization and feedback closed-loop control is constructed, and the reproducibility of the construction technology, the safety of the operation process and the overall engineering quality are improved.

Description

Technical Field

[0001] This specification relates to the field of engineering construction, and more specifically, the present application relates to a construction method and system for controlling tunnel over-excavation and under-excavation with the assistance of a multifunctional tunnel boring machine. Background Art

[0002] In large-section tunnels built in soft rock or soil, due to the loose structure, large deformation, and poor stability of the surrounding rock, most current projects still rely on manual labor to perform over-excavation and under-excavation repairs. However, this traditional, manual approach presents numerous challenges, including long construction periods, complex procedures, significant disturbances, and low safety factors, which severely impact construction efficiency and quality control.

[0003] Under Grade IV and V rock conditions, tunnels are typically excavated in sections using a benching method. This carries a significant risk of rock instability, and existing support systems (such as initial shotcrete support) often struggle to provide timely and effective support. This creates the potential for collapse or falling blocks, posing a serious threat to construction workers. Furthermore, manual repair of underexcavated areas is difficult, leading to substandard finish quality and ultimately impacting secondary lining construction and the lifespan of the structure.

[0004] In recent years, China has gradually carried out research on a complete set of technologies for large-scale mechanized drilling and blasting construction of tunnels with soft surrounding rocks, attempting to break through the existing bottlenecks of low construction efficiency, poor contour quality, and weak safety guarantees, and to build an integrated and efficient construction system including construction technology, equipment systems, and specifications and standards.

[0005] However, current research focuses more on hard rock or relatively stable surrounding rock sections. There is still a lack of a construction method for multifunctional tunnel boring machine-assisted control of tunnel over-excavation and under-excavation, as to how to achieve blasting forming quality control and intelligent coordinated finishing of tunnel boring machines under complex geological conditions. Summary of the Invention

[0006] The Summary of the Invention introduces a series of simplified concepts that will be further described in the Detailed Description of the Invention. The Summary of the Invention of this application is not intended to limit the key features and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0007] In a first aspect, the present application proposes a construction method for controlling tunnel over-excavation and under-excavation with the assistance of a multifunctional roadheader, comprising: Obtain the design profile information and geological parameter information of the target tunnel; Determine the underbreak contour design information corresponding to the blasting forming based on the design contour information and the geological parameter information; Determine blasting point information and blasting charge quantity information based on the underbreak contour design information and the geological parameter information; After the blasting is completed, the post-blasting contour is scanned to obtain the post-blasting contour information; The multifunctional roadheader is controlled to perform fine trimming and leveling on the above-mentioned contour information after blasting, so that the actual contour information is close to the above-mentioned designed contour information.

[0008] In a feasible implementation manner, the above-mentioned determination of the underbreak contour design information corresponding to the blasting forming based on the above-mentioned design contour information and the above-mentioned geological parameter information includes: Based on the geological parameter information and the locations of different areas of the tunnel section, differentiated underbreak offset rules are used to determine the underbreak offset value of each area, wherein the differentiated underbreak offset rules include the corresponding relationship between the underbreak offset values under different geological conditions and different applicable areas; The design contour is processed using the normal offset algorithm. The contour points are offset inward along the normal direction according to the undercut offset values of each area mentioned above. The undercut contour line is continuously reconstructed using the Bezier curve smoothing algorithm to form a two-dimensional undercut contour line. The above two-dimensional underbreak contour is longitudinally extended to generate a three-dimensional underbreak contour surface to determine the underbreak contour design information corresponding to the blasting forming.

[0009] In a feasible implementation manner, the above method further includes: A complete rationality check is performed on the above-mentioned under-excavation contour design information to optimize the above-mentioned under-excavation contour design information, wherein the above-mentioned complete rationality check is verified by a contour closure check algorithm, a self-intersection conflict detection algorithm, a structural clearance verification algorithm and a preliminary surrounding rock stability simulation algorithm.

[0010] In a feasible implementation manner, the determination of blasting point information and blasting charge quantity information based on the underbreak contour design information and the geological parameter information includes: The tunnel section is divided into multiple eyelet areas based on the spatial position, surrounding rock strength, rock mass integrity and designed section structure of the above undercut profile design information; For each of the above-mentioned hole arrangement areas, an equidistant offset method in the normal direction is used to generate the above-mentioned blasting point information along the undercut contour line, wherein the above-mentioned blasting point information includes the position information, direction information and depth information of the blasting hole; The energy balance model is used to calculate the unit charge and total charge of each blast hole based on the uniaxial compressive strength of the surrounding rock, the type of explosive, the detonation velocity and the blasting efficiency. A differentiated charging strategy is adopted to set different blasting parameters for different areas of the arch, arch waist and side walls to control the blasting range and forming accuracy.

[0011] In a feasible implementation, the above-mentioned differentiated charging strategy is used to set different blasting parameters for different areas of the vault, haunch, and sidewall to control the blasting range and forming accuracy, including: According to the area type to which the above blasting point information belongs, the tunnel section is divided into the vault area, the waist area and the side wall area; A charge adjustment coefficient is set for each area, wherein the charge adjustment coefficient of the arch area is less than 1.0, the adjustment coefficient of the waist area is 1.0-1.1, and the adjustment coefficient of the side wall area is greater than 1.1; Combined with the above charge adjustment coefficient, the final unit charge and total charge of each blasting hole are determined; The blasting charge structure and detonation delay parameters are set according to the above-mentioned area types. Among them, the above-mentioned arch area adopts intermittent charging and delayed detonation, and the above-mentioned side wall area adopts continuous high-density charging and early detonation.

[0012] In a feasible implementation manner, controlling the multifunctional roadheader to fine-tune and level the post-blasting contour information so that the actual contour information approaches the designed contour information includes: Perform spatial registration between the post-blasting contour information and the designed contour information, calculate the offset of each contour point, and extract the area with excessive deviation as the target area for refinement; Generating operation path information of the multifunctional roadheader based on the refined target area, wherein the operation path information includes operation start and end positions, operation sequence, dressing depth, and tool contact angle; Controlling the working head of the multifunctional tunnel boring machine to perform a finishing operation according to the operation path, removing excess rock or protruding parts, and making the actual contour information approach the designed contour information; After the job is completed, the trimmed area is scanned again. If the scan results show that there is still a deviation exceeding the set threshold, a secondary refinement process is triggered until the actual contour meets the design accuracy requirements.

[0013] In a feasible implementation manner, the above-mentioned generating the operation path information of the multifunctional roadheader based on the above-mentioned refined target area includes: Discretize the above-mentioned refinement target area into multiple refinement task units, and construct a path search graph containing the reachability relationship between each task unit; Set the path cost function and use the pheromone concentration of individual ant colonies to guide the path exploration process; Construct a multi-objective fitness function; Through multiple rounds of ant colony evolution iteration, a set of Pareto optimal path sets is generated; The path with the lowest comprehensive operation cost is selected from the above Pareto optimal paths as the refined operation path, and the above operation path information is output.

[0014] In a feasible implementation, the multi-objective fitness function includes the total path length, cutting energy consumption, processing efficiency and the number of tunnel boring machine posture switching times.

[0015] In a feasible implementation manner, the above method further includes: Based on the scan results after the first refinement operation, local areas where the residual deviation still exceeds the set accuracy threshold are identified as target areas for the second refinement; Regenerate a local refined path specifically for secondary finishing, adopt a high-precision low-speed cutting mode, and adapt to the end flexible operating arm of the multi-functional tunnel boring machine for limited area operations.

[0016] In a second aspect, the present invention further proposes a construction control system for a multifunctional roadheader to assist in controlling tunnel over-excavation and under-excavation, comprising: A first acquisition unit is used to acquire design profile information of a target tunnel; A first determining unit is configured to determine undercut profile design information corresponding to blasting forming based on the above-mentioned design profile information; A second determining unit is configured to determine blasting point information and blasting charge quantity information based on the underbreak contour design information; The second acquisition unit is used to scan the post-blasting contour after the blasting is completed to obtain the post-blasting contour information; The control unit is used to control the multifunctional roadheader to perform fine trimming and leveling on the above-mentioned contour information after blasting, so that the actual contour information is close to the above-mentioned designed contour information.

[0017] In summary, the present invention provides a construction method for controlling over-excavation and under-excavation of tunnels with a multifunctional tunnel boring machine. This method addresses the problems of low over-excavation forming accuracy, difficulty in manual trimming, and high safety risks in tunnels with weak surrounding rocks. By introducing differentiated under-excavation offset rules, the normal of the design contour is inward-adjusted in combination with the surrounding rock grade and cross-sectional position, and a three-dimensional under-excavation contour model is constructed. This effectively avoids over-excavation in weak structural areas and enhances the self-stabilization ability of the surrounding rock and the coordination of the support structure. According to the different surrounding rock structure characteristics and cross-sectional positions, the partitioned charge amount and detonation parameters are set to achieve a balanced spatial distribution of blasting energy. In particular, in easily broken areas such as vaults and interlayers, small-charge intermittent blasting is used to reduce disturbances and ensure contour control effects. A three-dimensional scanner is used to obtain the contour after blasting, and the system automatically identifies the deviation exceeding the limit area and constructs a refined target surface to avoid misjudgment and repeated trimming caused by subjective manual judgment. Through an intelligent algorithm, the optimal refined path is generated by combining parameters such as path length, energy consumption, and cutting posture switching, which greatly improves the refinement efficiency, reduces the posture adjustment time, and improves the forming consistency. For local areas where the initial refinement still fails to meet accuracy requirements, a secondary refinement path planning process is automatically triggered, combined with the multifunctional tunnel boring machine's flexible arm's limited-area operation mode to ensure that the final contour accuracy meets the requirements, providing a reliable reference interface for subsequent lining construction. This method establishes a coordinated mechanism for the entire process, from "differentiated blasting design - refinement target identification - tunneling path optimization - feedback closed-loop control", improving the replicability of the construction process, the safety of the operation process, and the overall project quality.

[0018] Other advantages, objectives and features of the present application will be reflected in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present description. The same reference symbols are used throughout the drawings to represent the same components. In the drawings: Figure 1 A schematic flow chart of a construction method for controlling tunnel over-excavation and under-excavation with the assistance of a multifunctional tunnel boring machine provided by the present invention.

[0020] Figure 2 A schematic diagram of the process of determining the undercut profile design information corresponding to blasting forming provided by the present invention Figure 3 A schematic diagram of the process of determining blasting point information and blasting charge quantity information provided by the present invention; Figure 4 A schematic diagram of the process of adopting a differentiated charging strategy method provided by the present invention; Figure 5 A schematic diagram of the process of a method for fine-tuning and leveling contour information after blasting provided by the present invention; Figure 6 A schematic diagram of the process of generating operation path information of a multifunctional roadheader provided by the present invention; Figure 7 A schematic diagram of the process of a secondary refinement method provided by the present invention; Figure 8 This is a structural schematic diagram of a construction control system for a multifunctional tunnel boring machine to assist in controlling tunnel over-excavation and under-excavation provided by the present invention. DETAILED DESCRIPTION

[0021] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate so that the embodiments described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices. The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the embodiments described are only some embodiments of the present application, not all embodiments.

[0022] See also Figure 1 , which is a schematic flow chart of a construction method for controlling tunnel over-excavation and under-excavation with assistance of a multifunctional roadheader provided in an embodiment of the present application, which may specifically include: S110, obtaining design profile information and geological parameter information of the target tunnel; S120, determining underbreak profile design information corresponding to blasting based on the design profile information and the geological parameter information; S130, determining blasting point information and blasting charge information based on the underbreak profile design information and the geological parameter information; S140, after the blasting is completed, scanning the post-blasting contour to obtain post-blasting contour information; S150: Control the multifunctional roadheader to perform fine trimming and leveling on the post-blasting contour information so that the actual contour information is close to the designed contour information.

[0023] For example, tunnel cross-section design profile information is first extracted from tunnel design drawings, BIM models, or CAD data, including cross-section coordinates, geometry, and segmented structures (e.g., vault, haunch, and sidewalls). Simultaneously, geological survey data is used to obtain geological parameter information for the target section, including surrounding rock grade, lithology, uniaxial compressive strength, structural surface characteristics, and rock mass integrity index (RQD). This provides a foundation for subsequent construction parameter adjustments and blasting design.

[0024] Based on the location and geological parameters of each area in the design outline, a differentiated underbreak offset strategy is implemented, setting underbreak offsets for different locations. For example, if the arch is geologically fragmented, a 50cm offset is set, while if the sidewalls are stable, a 30cm offset is set. Subsequently, a normal offset algorithm is used to retract the design outline, and the resulting underbreak contour is smoothly reconstructed using Bezier curves to form a two-dimensional continuous underbreak contour. If the tunnel is a three-dimensional model structure, further longitudinal extension is performed to construct a complete three-dimensional underbreak contour surface. This underbreak contour surface serves as the control target for blasting.

[0025] The three-dimensional undercut profile is projected onto the cross-sectional plane. Based on its morphology and geological conditions, the tunnel section is divided into multiple hole placement zones: the vault, haunch, and sidewall. For each zone, blasting point information is generated along the normal direction of the undercut profile, including the blasthole's location coordinates, direction, and depth. An energy balance model is then used to calculate the unit charge and total charge required for each blasthole based on the surrounding rock strength, explosive performance parameters (density, detonation velocity), and blasting efficiency. Furthermore, to control the blasting range and profile accuracy, differentiated charging structures and detonation delay parameters are set for different zones. For example, intermittent charging and delayed detonation are used in the vault zone, while high-density continuous charging and early detonation are used in the sidewall zone.

[0026] After blasting and mucking, the tunnel face and surrounding sections are scanned using 3D laser scanning equipment. By comparing the point cloud data with the pre-set design contours, undercut areas and residual protrusions are identified, a post-blasting contour information model is constructed, and deviation values for each area are calculated.

[0027] By comparing the post-blasting contour with the designed contour, the area with excessive deviation is extracted as the target area for fine-tuning. The fine-tuning area is divided into multiple sub-task units, and an intelligent path planning algorithm is used to comprehensively consider factors such as path length, energy consumption, and processing efficiency to generate the optimal fine-tuning path information including the start and end points of the operation, sequence, trimming depth, and cutter head angle. The working head of the multi-functional roadheader is controlled to perform fine-tuning operations according to this path, trimming the protruding parts until the contour deviation is controlled within the preset accuracy threshold. If there is still residual deviation in the scan after fine-tuning, the secondary fine-tuning process is triggered, and high-precision low-speed trimming is performed again only on the local area, ultimately making the actual contour stable and meet the design requirements.

[0028] The present invention provides a construction method for controlling tunnel over- and under-break with the assistance of a multifunctional tunnel boring machine. This method addresses the problems of low over- and under-break forming accuracy, difficulty in manual trimming, and high safety risks in tunnels with weak surrounding rock. By introducing differentiated under-break offset rules and combining the surrounding rock grade and cross-sectional location to inward-adjust the normal of the design contour, a three-dimensional under-break contour model is constructed. This effectively avoids over-break in structurally weak areas and enhances the self-stabilizing capacity of the surrounding rock and the coordination of the support structure. Based on the different surrounding rock structural characteristics and cross-sectional locations, the zone charge amount and detonation parameters are set to achieve a balanced spatial distribution of blasting energy. In particular, in easily broken areas such as vaults and interlayers, small-charge intermittent blasting is used to reduce disturbances and ensure contour control effectiveness. A three-dimensional scanner is used to obtain the post-blasting contour. The system automatically identifies areas with excessive deviations and constructs a refined target surface, avoiding misjudgments and repeated trimming caused by subjective manual judgment. An intelligent algorithm is used to generate the optimal refined path based on parameters such as path length, energy consumption, and cutting posture switching, significantly improving refinement efficiency, reducing posture adjustment time, and improving shaping consistency. For local areas where the initial refinement still fails to meet accuracy requirements, a secondary refinement path planning process is automatically triggered, combined with the multifunctional tunnel boring machine's flexible arm's limited-area operation mode to ensure that the final contour accuracy meets the requirements, providing a reliable reference interface for subsequent lining construction. This method establishes a coordinated mechanism for the entire process, from "differentiated blasting design - refinement target identification - tunneling path optimization - feedback closed-loop control", improving the replicability of the construction process, the safety of the operation process, and the overall project quality.

[0029] In one possible implementation, Figure 2 FIG. 1 is a flow chart of a method for determining underbreak profile design information corresponding to blasting forming provided by the present invention. Step S120 determines the underbreak profile design information corresponding to blasting forming based on the design profile information and the geological parameter information, including: S1201. Determine an underbreak offset value for each region using a differentiated underbreak offset rule based on the geological parameter information and the locations of different regions of the tunnel section, wherein the differentiated underbreak offset rule includes a correspondence between underbreak offset values under different geological conditions and different applicable regions. S1202, processing the designed contour using a normal offset algorithm, performing inward offsets on the contour points along the normal direction according to the undercut offset values of the above-mentioned respective regions, and continuously reconstructing the undercut contour line using a Bezier curve smoothing algorithm to form a two-dimensional undercut contour line; S1203 , longitudinally extend the two-dimensional underbreak contour to generate a three-dimensional underbreak contour surface to determine the underbreak contour design information corresponding to the blasting forming.

[0030] For example, based on the acquired geological parameters (such as surrounding rock grade, lithology, rock mass integrity index (RQD), bedding fracture development, etc.) and the location of the tunnel design profile in different cross-sectional areas (such as the crown, haunch, sidewalls, and invert), a set of pre-defined differentiated underbreak offset rules is used to set adaptive underbreak amounts for each area. These rules can be derived from historical engineering experience, field test data, or an expert system. Specifically, the following example correspondence is shown in Table 1: Table 1 After obtaining the undercut offset value for each area, the design contour is normalized. For each point in the design contour, the tangent direction is calculated, and the normal direction vector is then solved using the right-hand rule. Each point is offset inward along its normal direction by a corresponding distance (based on the aforementioned area settings). The resulting discrete point set may contain localized abrupt changes or sharp corners. Continuity fitting is performed using Bezier curves or B-spline curves to ensure the contour maintains geometric first-order / second-order continuity (G¹ or G²). Ultimately, a two-dimensional undercut contour that meets construction requirements is formed.

[0031] The 2D contour line is replicated along the tunnel's longitudinal axis (usually the mileage direction). The contour line can be replicated at equal intervals for each longitudinal step (e.g., every 1 meter or every 3 meters per blast cycle). If longitudinal geological conditions vary, locally differentiated 2D contour lines can be generated for each mileage segment. A smooth 3D contour surface is then formed using profile interpolation or stretch-and-splice algorithms. The final output is a 3D undercut contour surface model, which serves as the target surface for blasting control. This 3D model can be imported into blasting simulation and hole placement software for verification and can also serve as a boundary reference for subsequent scanning comparisons and roadheader refinement control.

[0032] Through the step-by-step processing method of S1201 to S1203, this embodiment can finely construct blasting-formed under-break contour information with engineering adaptability and geometric continuity on the basis of considering complex geological differences and tunnel geometric structure, providing high-precision input conditions for accurate eye placement and subsequent mechanical finishing.

[0033] In a feasible implementation manner, the above method further includes: S1204. Perform a complete rationality check on the above-mentioned under-excavation contour design information to optimize the above-mentioned under-excavation contour design information, wherein the above-mentioned complete rationality check is verified by a contour closure check algorithm, a self-intersection conflict detection algorithm, a structure clearance check algorithm and a preliminary surrounding rock stability simulation algorithm.

[0034] For example, firstly, the geometric closure of the generated 2D or 3D undercut contour line is judged. Let the contour line be the point set The polygonal curve is constructed to determine whether it is closed at both ends: in: is the Euclidean distance between the first and last points; are the coordinates of the end point and starting point of the contour line. (For example ), it is judged as a closed contour; otherwise, repair processing is required (such as interpolation closure, line filling, etc.).

[0035] Detect whether there is self-intersection in the contour line (i.e. a curve intersects itself at a non-endpoint). and For example, if the following conditions are met, there is self-intersection: in, Represents a vector The existence of self-intersection will affect the subsequent eye formation and blasting energy distribution, and the conflicting areas need to be automatically eliminated or reconstructed.

[0036] Verify whether there is space intrusion between the undercut contour and the designed structure (such as steel arch, anchor arrangement area, drainage pipe groove). , calculate the minimum distance from it to the structural boundary (such as the outermost edge line of the steel frame): in: is the set of structural boundary points; is the minimum clearance distance. (such as 20cm), it is judged as a clearance conflict, prompting contour adjustment or structural rearrangement.

[0037] In order to verify that the undercut profile will not cause large-scale instability during construction, a preliminary mechanical analysis is performed using a two-dimensional plane stress finite element model. Assume that the rock mass elastic modulus is , Poisson's ratio is 、Yan Zhongwei , calculate the surrounding rock safety factor by strength reduction method : in, is the original cohesion and internal friction angle; It is the critical parameter that causes the surrounding rock to become unstable.

[0038] like , it means that the contour design has self-stabilizing ability; if , it is recommended to correct the undercut profile or strengthen the primary support design.

[0039] Through four-fold verification of contour closure, self-intersection detection, structural clearance, and stability, this step can effectively optimize the undercut contour design, avoid geometric deformities and construction interference issues, and ensure that the surrounding rock has sufficient mechanical safety before blasting, providing a reliable foundation for subsequent hole placement and tunnel boring machine construction.

[0040] In one possible implementation, Figure 3 FIG. 1 is a flow chart of a method for determining blasting point information and blasting charge information provided by the present invention. Step S130 determines the blasting point information and blasting charge information based on the underbreak contour design information and the geological parameter information, including: S1301. Divide the tunnel section into multiple eyelet areas based on the spatial position, surrounding rock strength, rock mass integrity, and designed cross-sectional structure of the undercut profile design information. S1302: for each of the above-mentioned hole arrangement areas, using a normal direction equidistant offset method, generate the above-mentioned blasting point information along the undercut contour line, wherein the above-mentioned blasting point information includes the position information, direction information and depth information of the blasting hole; S1303. Calculate the unit charge and total charge for each blast hole using an energy balance model based on the uniaxial compressive strength of the surrounding rock, the type of explosive, the detonation velocity, and the blasting efficiency. S1304. Adopt a differentiated charging strategy and set different blasting parameters for different areas of the arch, arch waist and side wall to control the blasting range and forming accuracy.

[0041] For example, multiple drill hole placement areas within the tunnel section are first delineated based on the generated 3D undercut profile and its positional relationship within the tunnel space, combined with geological parameter information. These areas are typically divided according to the cross-sectional structure: the crown area is the upper portion of the profile, where block dropouts must be avoided; the haunch area is the transition between the crown and the sidewalls; and the sidewall area is a near-vertical structure. Rock mass integrity is typically assessed by adding corresponding geological parameters to each area, such as the surrounding rock's uniaxial compressive strength, RQD (Rock Mass Integrity Index), and joint density, to guide drill hole placement and charge calculations.

[0042] For each hole layout area, the equidistant offset method in the normal direction is adopted to generate blasting points according to the undercut contour line: the undercut contour line is discretized and a discrete point sequence is extracted; the local normal direction of each point is calculated; the center position of the blasting hole is arranged by equidistantly offsetting a certain distance (such as 0.5m) along the normal direction; the direction of the blasting hole is set according to the structural form of the area (mostly perpendicular to the contour or converged 5° to 10° towards the center of the tunnel face); the depth of the blasting hole is determined according to the strength of the surrounding rock and the thickness of the blasting contour (for example, 1.2~2.8m).

[0043] The blasting point information finally generated includes the spatial coordinates, direction vector and hole depth of each blast hole, forming a structured point data table, which provides a basis for the design of blasting eye pattern.

[0044] Based on the rock mass strength and explosive performance parameters at each blast hole location, the energy balance model is used to calculate the unit charge and total charge. The theoretical basis is: in: Unit charge quantity ( ); The blasting radius is generally 60-80% of the blasthole spacing. is the uniaxial compressive strength of surrounding rock (MPa); is the blasting efficiency (usually 0.25 to 0.4); is the density of explosives ; is the explosive detonation velocity ( ).

[0045] The total charge amount is: in, The calculation results are output in a structured format, including parameters such as the unit charge per hole, total charge, and charge pack layout.

[0046] Specifically, in the vault area, due to its relatively fragile structure and prone to block fall, and the high requirements for forming in the space above, a small intermittent charge method is used. Empty sections are placed in the blasthole to absorb the energy of the blast wave and reduce the impact of the explosives on the surrounding rock. Simultaneously, combined with delayed detonation technology, explosive stress is preferentially released in other areas before stimulating the vault area, thereby reducing disturbances caused by the blast and improving contour smoothness.

[0047] The arch waist area, situated at the transition point between the arch crown and the sidewalls, bears certain structural loads and exhibits complex spatial variations. Therefore, a medium charge weight is employed, supplemented by a composite charge structure of "charge-air-charge." This structure effectively regulates the distribution and transfer of blasting energy, resulting in a uniform blasting effect. Regarding detonation timing, standard detonation delay parameters are typically used in the arch waist area to coordinate the energy release rhythm during the blasting process and prevent problems such as localized over-explosion or misfires.

[0048] In the sidewall area, the rock mass is relatively well-organized and has strong lateral constraints, so continuous charging can be used to ensure sufficient blasting. The charge in this area is appropriately increased, and detonation is prioritized to form a stable detonation surface, providing an effective unloading channel for blasting in subsequent areas and improving overall forming stability.

[0049] Furthermore, in areas with weak structures such as mudstone and muddy interlayers, hollow hole technology can be flexibly introduced during construction to prevent overexcavation or block drop caused by abnormal propagation of explosive energy within the weak layers. By arranging non-charged holes or hollow buffer holes, the explosive's range of action can be further reduced, thereby enhancing the controllability and contour stability of the blasting process.

[0050] In summary, implementing a differentiated charging strategy based on differences in cross-section location and geological structure helps achieve precise blasting, reduces disturbance to the surrounding rock structure, and provides better initial contour conditions for subsequent finishing operations of the multifunctional roadheader.

[0051] In one possible implementation, Figure 4 FIG. 1 is a flow chart of a method for adopting a differentiated charging strategy provided by the present invention. Step S1304 adopts a differentiated charging strategy to set different blasting parameters for different areas of the vault, haunch, and sidewall to control the blasting range and forming accuracy, including: S13041. Divide the tunnel cross section into a vault area, a waist area, and a sidewall area according to the area type to which the blasting point information belongs. S13042. Set a charge adjustment coefficient for each area, wherein the charge adjustment coefficient of the arch area is less than 1.0, the adjustment coefficient of the waist area is 1.0-1.1, and the adjustment coefficient of the sidewall area is greater than 1.1; S13043. Determine the final unit charge and total charge of each blast hole based on the charge adjustment coefficient. S13044. Set the blasting charge structure and detonation delay parameters according to the above-mentioned area types, wherein the above-mentioned vault area adopts intermittent charging and delayed detonation, and the above-mentioned side wall area adopts continuous high-density charging and early detonation.

[0052] For example, in order to further improve the molding quality of the blasting profile and ensure the accuracy and efficiency of the subsequent finishing operations of the multifunctional tunnel boring machine, step S1304 adopts a differentiated charging strategy, and sets targeted blasting parameters for different areas in the tunnel section to achieve precise control of the blasting range and profile molding accuracy.

[0053] In step S13041, the entire tunnel cross-section is divided into three typical regions: the vault, haunch, and sidewall, based on the spatial locations of each blasthole in the aforementioned blasting point information and the geometric characteristics of the designed profile. This division is based on the vertical and lateral morphological differences of the tunnel structure, combined with empirical data on the stress state of the surrounding rock and the areas most susceptible to disturbance after blasting, to facilitate the subsequent development of blasting plans.

[0054] In step S13042, different charge adjustment coefficients are assigned to different regions, serving as proportional factors for charge design, based on the differences in forming difficulty and structural stability. Specifically, the vault region, due to its weak structure and high risk of falling blocks, uses a lower charge strength, with a charge adjustment coefficient set to less than 1.0 (e.g., 0.85-0.95). The waist region, with its strong structural transition and uniform load distribution, has a charge adjustment coefficient set to 1.0-1.1 to maintain a uniform forming effect. The sidewall region, with its wide load-bearing surface and large forming area, can appropriately increase the blasting strength, and the charge adjustment coefficient is set to greater than 1.1 (e.g., 1.15-1.25) to enhance rock breaking.

[0055] In step S13043, the final unit charge and total charge for each blasthole are determined by combining the calculated baseline charge (e.g., the unit charge calculated using the energy balance method) with the charge adjustment coefficient. For example, if the baseline unit charge is 0.6 kg / m and the adjustment coefficient for the dome area is 0.9, the final unit charge for the dome blasthole is 0.54 kg / m, and the total charge is this value multiplied by the hole depth.

[0056] In step S13044, the corresponding blasting charge structure and detonation sequence parameters are set according to the area type to which the blasthole belongs to enhance the forming control accuracy: the arch area adopts an intermittent charge structure (such as a charge-air-charge structure) to reduce the blasting wave peak value through the air section, and adopts a delayed detonation method (such as a delay of 50 to 80 ms) to make it detonate after the arch waist and side wall areas, thereby reducing the disturbance to the arch surrounding rock; the arch waist area uses an ordinary continuous charge structure and sets a conventional detonation sequence; the side wall area adopts a continuous high-density charge to enhance the rock breaking ability, and configures an early detonation sequence (such as 20 to 40 ms in advance) to form a stable initial blasting surface, thereby improving the continuity and forming integrity of the overall contour blasting.

[0057] The combined application of the above strategies not only achieved directional control of blasting effects in different areas, but also effectively reduced the risk of over-excavation and improved the consistency between the actual contour line and the designed contour, thereby providing a more ideal working surface for subsequent tunnel boring machine finishing operations and significantly improving the overall construction quality and efficiency of the tunnel.

[0058] In one possible implementation, Figure 5 FIG. 1 is a flow chart of a method for fine-tuning and leveling the contour information after blasting provided by the present invention. The step S150 controls the multifunctional roadheader to fine-tune and level the contour information after blasting so that the actual contour information is close to the designed contour information, including: S1501, spatially registering the post-blasting contour information with the designed contour information, calculating the offset of each contour point, and extracting the area with excessive deviation as the target area for refinement; S1502: generating operation path information of the multifunctional roadheader based on the refined target area, wherein the path information includes operation start and end positions, operation sequence, dressing depth, and tool contact angle; S1503: Control the working head of the multifunctional roadheader to perform a finishing operation according to the operation path, remove excess rock or protrusions, and make the actual contour information approach the designed contour information; S1504: After the operation is completed, the trimmed area is scanned again. If the scanning result shows that there is still a deviation exceeding the set threshold, a secondary refinement process is triggered until the actual contour meets the design accuracy requirements.

[0059] For example, the actual contour information obtained from the post-blasting scan is spatially registered with the designed contour information. This registration can utilize a 3D point cloud registration algorithm to ensure precise alignment within the coordinate system. After registration, the spatial distance between the actual and designed contours is compared point by point, and the offset for each point is calculated. By setting a forming deviation threshold (e.g., ±5 cm), all areas exceeding this threshold are extracted to form the areas to be trimmed, serving as targets for subsequent refinement.

[0060] For the above-mentioned target area for fine-tuning, the system discretizes it into multiple work units, each of which includes spatial position, depth to be trimmed, and direction information. During the path planning process, the complete work path information of the multi-functional roadheader is generated, specifically including: determining the entry and exit points of each work path. Path sorting is performed among multiple target units, and an improved A* algorithm or a multi-objective ant colony algorithm can be used to achieve optimal efficiency. The cutting depth of each point is determined based on the offset value. Based on the normal direction of the surface to be trimmed, the optimal contact angle between the roadheader working head (such as a hob or milling head) and the surface is calculated to avoid miscutting or slipping. This path information will serve as input for controlling the motion trajectory of the roadheader and the cutting process parameters.

[0061] Based on the generated path information, the multi-functional roadheader's end effectors (such as hydraulic arms and rolling cutters) are controlled to perform high-precision operations. During the operation, the roadheader automatically adjusts its posture, cutting angle, and propulsion speed, removing excess rock or protrusions point by point at the preset cutting depth. This finishing process utilizes a high-frequency, low-impact cutting method to minimize disturbance to the surrounding rock structure and minimize dust, vibration, and noise.

[0062] After the job is complete, the trimmed area is scanned again to obtain updated actual contour information. The same spatial registration and deviation analysis steps as in S1501 are repeated to determine whether any remaining areas still contain deviations exceeding the set accuracy threshold. This process is repeated until all contour deviations are within the specified range (e.g., ±2 cm). This ensures that the final shape meets design requirements and provides a high-quality reference interface for subsequent support structure construction (such as steel arches or shotcrete anchors).

[0063] This embodiment, through a four-step closed-loop refinement control process, effectively achieves high-precision finishing and quality verification of the tunnel contour after blasting. It also enables automatic iterative adjustments, enabling unattended, precise construction control. This method significantly improves shaping accuracy, reduces the risk of over-excavation and under-excavation, and provides intelligent support for mechanized tunnel construction.

[0064] In one possible implementation, Figure 6 FIG. 1 is a flow chart of a method for generating operation path information of a multifunctional roadheader provided by the present invention. Step S1502 generates the operation path information of the multifunctional roadheader based on the refined target area, including: S15021. Discretize the refinement target area into a plurality of refinement task units, and construct a path search graph including reachability relationships between the task units; S15022. Set a path cost function and use the pheromone concentration of individual ant colonies to guide the path exploration process; S15023. Construct a multi-objective fitness function; S15024. Generate a set of Pareto optimal paths through multiple rounds of ant colony evolution iterations; S15025. Select the path with the lowest comprehensive operation cost from the above Pareto optimal paths as the refined operation path, and output the above operation path information.

[0065] In a feasible implementation, the multi-objective fitness function includes the total path length, cutting energy consumption, processing efficiency and the number of tunnel boring machine posture switching times.

[0066] For example, the deviation-exceeding region (i.e., the target area for refinement) extracted in step S1501 is discretely divided into several refinement task units. Each unit corresponds to a spatial region requiring refinement and has a specific location, refinement depth, and normal direction. A path search graph is then constructed based on the relative spatial positions of each task unit, the roadheader's motion constraints (such as turning radius and maximum reach), and the operation sequence constraints. Nodes in the graph represent refinement task units, and edges represent feasible paths between tasks. Edge weights are initially set to zero and are dynamically assigned during subsequent evolution.

[0067] Next, we define a path cost function in the graph as the navigation basis for the ant colony's path search. The path cost not only considers the path length, but also factors such as the depth of the repair and the jumpiness of the task sequence to establish a cost model. An example is shown below: in: is the Euclidean distance between task units i and j; To adjust the depth change value; AngleChange is the contact angle change; is the adjustment factor.

[0068] During the path search process, each ant colony individual ) and path cost ( ) selects the next node, and the transition probability is: in, For Ant slave nodes Select Transfer to Node probability; For the edge Current pheromone concentration value; Cost For the edge The heuristic value of (the inverse of the cost); To control the importance ratio of pheromone concentration to heuristic value, the common setting is ; allowed: The set of task units that have not been accessed yet.

[0069] Considering the comprehensiveness and complexity of path planning in actual engineering, the following multi-objective fitness function is set to comprehensively evaluate the quality of the path: in: is the total length of the path; is the cutting energy consumption per unit path; is the processing efficiency (number of unit tasks / time consumption), and the reciprocal is used to unify the minimization objective; The number of times the tunnel boring machine switches its posture; is the target weight coefficient, which can be adjusted to adapt to different working conditions (for example, efficiency or accuracy priority).

[0070] Ant colony agents independently iterate through multiple rounds on the path graph, gradually accumulating pheromones and searching for a set of feasible path solutions. After each round of evolution, the system evaluates the multi-objective fitness of the path solutions and applies a non-dominated sorting strategy to generate the Pareto-optimal path set for the current generation. Each path corresponds to a set of task access sequences and control parameters that optimally balance the trade-offs.

[0071] Finally, from the Pareto solution set, the path with the lowest overall cost is selected based on the actual cost model. This path is then converted into path control instructions recognizable by the multi-functional roadheader and output as the final refinement path information. This path information includes the start and end points of the operation, key intermediate nodes, the order in which refinement tasks are accessed, the corresponding refinement depth for each path segment, and the tool contact angle and feed method.

[0072] This implementation abstracts the complex high-dimensional refinement task into a graph structure and introduces a multi-objective ant colony optimization algorithm to intelligently search and evolve the path, making the path planning process self-learning, globally optimized, and adaptable to working conditions.

[0073] In one possible implementation, Figure 7 FIG. 1 is a flow chart of a secondary refinement method provided by the present invention, wherein the method further comprises: S210: Based on the scan results after the first refinement operation, identify a local area where the residual deviation still exceeds a set accuracy threshold as a target area for secondary refinement; S220, regenerates a local refinement path dedicated to secondary finishing, adopts a high-precision low-speed cutting mode, and adapts to the end flexible operating arm of the multi-functional tunnel boring machine for limited area operations.

[0074] For example, after the multifunctional roadheader completes its initial fine-tuning work and exits the working surface, the system rescans the tunnel cross-section using a high-precision 3D laser scanner (such as the Leica MS60). The scanned actual contour is spatially registered with the designed contour, and the 3D deviation is calculated point by point. Points with deviations exceeding a set accuracy threshold (e.g., ±2 cm) are marked as "residual deviation points."

[0075] Based on these deviation points, a mesh expansion algorithm is used to identify coherent areas of residual concentration and expand a certain boundary buffer zone (e.g., 1 cm) to ensure full coverage during the secondary refinement process. Ultimately, these areas are defined as "secondary refinement target areas" and serve as input for subsequent local refinement.

[0076] The system further divides the target area into multiple tiny finishing units (e.g., a 2cm x 2cm grid) and uses a local heuristic search algorithm to generate high-precision paths. To ensure consistent finishing, the maximum cutting depth of each path is limited to 5mm to avoid over-cutting or disturbing adjacent formed areas.

[0077] In terms of operating mode, the tunnel boring machine will switch to the "high-precision, low-speed cutting" mode, control the operating speed at 0.1-0.3m / min, monitor the cutting force feedback in real time, and dynamically adjust the propulsion speed through the constant torque control strategy to ensure processing accuracy and operation safety.

[0078] To adapt to local spatial variations, the system uses the multifunctional roadheader's flexible end-manipulator module and sets precise posture constraints to prevent collisions with arches, anchors, and other structures during cutting. The manipulator utilizes built-in inverse kinematics calculations and closed-loop position control to achieve ±1cm precision within a confined area.

[0079] This secondary refinement process not only effectively eliminates residual errors from the initial refinement but also avoids repeated adjustments to the entire tunnel section, significantly improving construction efficiency. Thanks to the synergy between the flexible arm's restricted operation and high-precision path control, this implementation can stably control the final profile error to within ±2cm, fully meeting the precision requirements for steel arch installation and lining construction.

[0080] Second, as Figure 8 As shown, the present invention also proposes a construction control system for a multifunctional roadheader to assist in controlling tunnel over-excavation and under-excavation, comprising: A first acquiring unit 21 is configured to acquire design profile information of a target tunnel; A first determining unit 22 is configured to determine undercut profile design information corresponding to blasting forming based on the above-mentioned design profile information; The second determining unit 23 is used to determine blasting point information and blasting charge information based on the underbreak contour design information; The second acquisition unit 24 is used to scan the post-blasting contour after the blasting is completed to obtain the post-blasting contour information; The control unit 25 is used to control the multifunctional roadheader to perform fine trimming and leveling on the above-mentioned post-blasting contour information so that the actual contour information is close to the above-mentioned designed contour information.

[0081] The multifunctional roadheader-assisted construction control system for controlling tunnel over-excavation and under-excavation proposed in the present invention can also execute the method described in any one of the first aspects.

[0082] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A construction method for controlling tunnel over-excavation and under-excavation with the assistance of a multifunctional tunnel boring machine, characterized in that: include: Obtain the design profile information and geological parameter information of the target tunnel; Determining underbreak contour design information corresponding to blasting based on the design contour information and the geological parameter information; Determining blasting point information and blasting charge information based on the underbreak contour design information and the geological parameter information; After the blasting is completed, the post-blasting contour is scanned to obtain the post-blasting contour information; The multifunctional roadheader is controlled to perform fine trimming and leveling on the post-blasting contour information so that the actual contour information is close to the designed contour information.

2. The method for controlling tunnel over-excavation and under-excavation with the aid of a multifunctional roadheader according to claim 1, characterized in that: The determining of underbreak contour design information corresponding to blasting based on the design contour information and the geological parameter information includes: Determining the underbreak offset value of each area using differentiated underbreak offset rules based on the geological parameter information and the locations of different areas of the tunnel section, wherein the differentiated underbreak offset rules include corresponding relationships between underbreak offset values under different geological conditions and different applicable areas; The design contour is processed using a normal offset algorithm, the contour points are offset inward along the normal direction according to the undercut offset value of each area, and the undercut contour line is continuously reconstructed using a Bezier curve smoothing algorithm to form a two-dimensional undercut contour line; The two-dimensional underbreak contour is longitudinally extended to generate a three-dimensional underbreak contour surface to determine the underbreak contour design information corresponding to the blasting forming.

3. The method for controlling tunnel over-excavation and under-excavation with the aid of a multifunctional roadheader according to claim 2, characterized in that: The method further comprises: The under-excavation contour design information is fully rationally checked to optimize the under-excavation contour design information, wherein the complete rationality check is verified by a contour closure check algorithm, a self-intersection conflict detection algorithm, a structural clearance check algorithm and a preliminary surrounding rock stability simulation algorithm.

4. The method for controlling tunnel over-excavation and under-excavation with the aid of a multifunctional roadheader according to claim 1, characterized in that: The determining of blasting point information and blasting charge quantity information based on the underbreak contour design information and the geological parameter information includes: Dividing the tunnel section into a plurality of eyelet areas according to the spatial position, surrounding rock strength, rock mass integrity and designed section structure of the undercut profile design information; For each of the hole-laying areas, an equidistant offset method in the normal direction is used to generate the blasting point information along the undercut contour line, wherein the blasting point information includes the position information, direction information and depth information of the blasting hole; The energy balance model is used to calculate the unit charge and total charge of each blast hole based on the uniaxial compressive strength of the surrounding rock, the type of explosive, the detonation velocity and the blasting efficiency. A differentiated charging strategy is adopted to set different blasting parameters for different areas of the arch, arch waist and side walls to control the blasting range and forming accuracy.

5. The method for controlling tunnel over-excavation and under-excavation with the aid of a multifunctional roadheader according to claim 4, characterized in that: The differentiated charging strategy is adopted to set different blasting parameters for different areas of the arch, arch haunch and sidewall to control the blasting range and forming accuracy, including: Dividing the tunnel section into a vault area, a waist area, and a sidewall area according to the area type to which the blasting point information belongs; Setting a charge adjustment coefficient for each area, wherein the charge adjustment coefficient of the arch area is less than 1.0, the adjustment coefficient of the waist area is 1.0-1.1, and the adjustment coefficient of the side wall area is greater than 1.1; Determine the final unit charge and total charge of each blast hole in combination with the charge adjustment coefficient; The blasting charge structure and detonation delay parameters are set according to the area type, wherein the vault area adopts intermittent charging and delayed detonation, and the side wall area adopts continuous high-density charging and early detonation.

6. The method for controlling tunnel over-excavation and under-excavation with the aid of a multifunctional roadheader according to claim 1, characterized in that: The controlling the multifunctional roadheader to perform fine trimming and leveling on the post-blasting contour information so that the actual contour information approaches the designed contour information includes: Perform spatial registration between the post-blasting contour information and the designed contour information, calculate the offset of each contour point, and extract the area with excessive deviation as the target area for refinement; Generating operation path information of the multifunctional roadheader based on the refined target area, wherein the path information includes operation start and end positions, operation sequence, dressing depth, and tool contact angle; controlling the working head of the multifunctional tunnel boring machine to perform a finishing operation according to the operation path, removing redundant rock masses or protruding parts, and making the actual contour information approach the designed contour information; After the job is completed, the trimmed area is scanned again. If the scan result shows that there is still a deviation exceeding the set threshold, a secondary refinement process is triggered until the actual contour meets the design accuracy requirements.

7. The method for controlling tunnel over-excavation and under-excavation with the aid of a multifunctional roadheader according to claim 6, characterized in that: The generating of the operation path information of the multifunctional roadheader based on the refined target area includes: Discretizing the refinement target area into a plurality of refinement task units, and constructing a path search graph including reachable relationships between the task units; Set the path cost function and use the pheromone concentration of individual ant colonies to guide the path exploration process; Construct a multi-objective fitness function; Through multiple rounds of ant colony evolution iteration, a set of Pareto optimal path sets is generated; A path with the lowest comprehensive operation cost is selected from the Pareto optimal path as a refined operation path, and the operation path information is output.

8. The method for controlling tunnel over-excavation and under-excavation with the aid of a multifunctional roadheader according to claim 7, characterized in that: The multi-objective fitness function includes the total path length, cutting energy consumption, processing efficiency and the number of tunnel boring machine posture switching times.

9. The method for controlling tunnel over-excavation and under-excavation with the aid of a multifunctional roadheader according to claim 6, characterized in that: The method further comprises: Based on the scan results after the first refinement operation, local areas where the residual deviation still exceeds the set accuracy threshold are identified as target areas for the second refinement; Regenerate a local refined path specifically for secondary finishing, adopt a high-precision low-speed cutting mode, and adapt to the end flexible operating arm of the multi-functional tunnel boring machine for limited area operations.

10. A construction control system for a multifunctional tunnel boring machine to assist in controlling tunnel over-excavation and under-excavation, characterized in that: include: A first acquisition unit is used to acquire design profile information of a target tunnel; A first determining unit is configured to determine undercut profile design information corresponding to blasting forming based on the design profile information; a second determining unit, configured to determine blasting point information and blasting charge quantity information based on the underbreak contour design information; The second acquisition unit is used to scan the post-blasting contour after the blasting is completed to obtain the post-blasting contour information; The control unit is used to control the multifunctional roadheader to perform fine trimming and leveling on the post-blasting contour information so that the actual contour information is close to the designed contour information.

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