A method for layer-by-layer rolling and breaking rock for a cantilevered hard rock rectangular cross section tunnel boring machine

Abstract

This invention relates to the field of hard rock tunneling construction technology in mine roadways and traffic tunnels, specifically disclosing a layered rolling rock breaking and shaping method for a cantilever hard rock rectangular section tunnel boring machine. The method includes: geological exploration and rock strata analysis: geological exploration of the rock strata of the roadway to be excavated to obtain geological parameters of the target rock strata, including uniaxial compressive strength, Protodyakonov hardness f, rock stratum thickness, joint development, and surrounding rock stability. This invention uses a disc-shaped roller cutter's rolling rock breaking mechanism to replace traditional cutting-tooth rock breaking. Through the combined action of static pressure crushing and rolling shearing, hard rock forms fissures and rapidly breaks under controllable loads, significantly improving single-pass rock breaking efficiency. Combined with layered tunneling technology, a large cross-section is decomposed into multiple small cross-sections for layered excavation, effectively reducing single-pass rock breaking resistance, increasing overall tunneling speed, and achieving efficient continuous tunneling of small-to-medium cross-section rectangular hard rock roadways.

Description

Technical Field

[0001] This invention relates to the field of hard rock tunneling construction technology in mine roadways and traffic tunnels, and particularly to a layered rolling rock breaking and forming method for a cantilever hard rock rectangular section tunnel boring machine. Background Technology

[0002] In underground mining, water conservancy, and transportation tunnel projects, small and medium-sized cross-section rectangular roadways and tunnels account for a very high proportion. Many of these projects face the challenge of tunneling through hard rock strata (Protodyakonov hardness f≥6). Currently, hard rock tunneling mainly uses two types of equipment: full-face hard rock tunneling machines (TBMs) and cantilever tunneling machines. Full-face hard rock TBMs use roller cutters to break rock across the entire cross-section, resulting in high rock-breaking efficiency and good forming quality. However, these machines are bulky and lack flexibility, making them only suitable for large-section, long-distance tunnel projects. For small and medium-sized cross-section, short-distance, and multi-turn rectangular mine roadways, TBMs are extremely unsuitable, and the equipment procurement and construction costs are extremely high, preventing their large-scale application.

[0003] Cantilever tunneling machines, with their advantages of flexible design, strong adaptability, and controllable cost, have become the core equipment for tunneling small-section roadways in mines. However, existing conventional cantilever tunneling machines all use a cutting mechanism based on cutting teeth, which has significant technical drawbacks when facing hard rock formations. Cutting teeth rely on the impact and shearing action of the cutting teeth to break the rock. Under hard rock conditions, the cutting teeth wear out very quickly, requiring frequent replacement, which significantly reduces tunneling efficiency and increases construction costs. During the cutting process in hard rock, the cutting resistance is high, the equipment load fluctuates violently, and the vibration is strong, which can easily lead to failures in the transmission components and hydraulic system, significantly shortening the equipment's service life. Conventional cantilever tunneling machines mostly use a full-section one-time cutting process, which is difficult to control the forming of rectangular sections, and is prone to over-excavation and under-excavation problems. In particular, the forming accuracy of the right-angle area of ​​the rectangular section is poor, which increases the difficulty and cost of subsequent roadway support construction. Existing processes lack a layered cutting and parameter adaptation mechanism for hard rock formations, and cannot dynamically adjust construction parameters according to changes in rock hardness, making it impossible to balance tunneling efficiency and equipment safety.

[0004] To address the aforementioned issues, relevant technical improvements have been implemented, such as equipping cantilever tunneling machines with high-strength cutting teeth and optimizing the cutting head structure. However, these improvements still do not deviate from the mechanism of cutting-type rock breaking and cannot fundamentally solve the problems of high cutting tooth wear and low rock breaking efficiency under hard rock conditions. Some studies have also proposed layered cutting processes, but these are only applicable to soft rock and coal roadway conditions and do not incorporate the mechanism of rolling rock breaking in hard rock to design suitable process paths and action flows. Consequently, they cannot achieve efficient and precise shaping of rectangular hard rock sections. Therefore, this paper proposes a layered rolling rock breaking and shaping method for cantilever hard rock rectangular section tunneling machines to solve the aforementioned problems. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, this invention provides a layered rolling rock breaking and shaping method for cantilever hard rock rectangular section tunnel boring machines. By adapting the rolling rock breaking mechanism to hard rock conditions, and combining a layered cutting scheme, standardized cutting actions, and a closed-loop reciprocating cutting path, this method solves the technical problems of low rock breaking efficiency, high tool wear, poor rectangular section forming accuracy, and large equipment load fluctuations of existing cantilever tunnel boring machines in hard rock conditions. This enables efficient, accurate, and low-cost tunneling of small and medium cross-section rectangular hard rock tunnels, effectively addressing the problems mentioned in the prior art.

[0006] The objective of this invention can be achieved through the following technical solution: This invention provides a layered rolling rock breaking and shaping method for a cantilever hard rock rectangular section tunnel boring machine, comprising the following steps: S1. Geological exploration and rock strata analysis: Geological exploration is carried out on the rock strata of the tunnel to be excavated to obtain the geological parameters of the target rock strata, including uniaxial compressive strength, Protodyakonov hardness f, rock strata thickness, joint development and surrounding rock stability. This provides a unique geological basis for setting the stratification parameters and operating parameters, and achieves rock excavation matching. S2. Determination of Rectangular Cross-Section Layering Parameters: Based on the obtained geological parameters of the rock strata and combined with the cross-sectional design dimensions of the target rectangular tunnel, determine the main layering excavation parameters of the cross-section, including the number of main layers, the thickness of a single main layer, and the excavation sequence, to form a layering scheme that uniquely corresponds to the characteristics of the rock strata and eliminate parameter coupling interference. S3. Setting the operating parameters of the tunneling machine: Based on the main layer tunneling parameters and the geological parameters of the rock strata, set the operating parameters of the cantilever tunneling machine, including the rotation speed of the cutterhead, the swing speed and advance speed of the cantilever, the penetration depth of single-step tunneling, the selection of tunneling path and rock breaking sequence, establish a deterministic mapping between the rock strata and the operating parameters, and realize adaptive hard constraint calibration. S4. Tunneling Cycle Operation: After the cantilever tunneling machine is in place and anchored, it rolls and breaks the rock in two rows of three-layer closed-loop paths in a counterclockwise or clockwise manner. The cutterhead rotates to assist in the accumulation of slag. It provides synchronous or step-by-step support and then cycles through tunneling after changing steps. This achieves full coverage of the cross-section by rolling and breaking the rock and directing the flow of slag, ensuring continuous tunneling. S5. Section Forming and Finishing Operations: After completing the tunnel excavation of the designed length, the machine is moved to a safe area to complete the cleaning of the working face, equipment maintenance and repair, and tunnel forming quality acceptance. The tunneling construction is then completed, and the section accuracy is accepted using quantitative indicators to ensure that the geometric quality of the tunnel meets the usage requirements.

[0007] Preferably, S2 specifically includes: The number of main layers is determined based on the obtained Protodyakonov hardness f: when f=8~12, the number of main layers is 3~5 layers; when f=12~15, the number of main layers is 5~6 layers; when f>15, the number of main layers is 6~8 layers. The thickness of a single layer does not exceed the thickness of the roller cutter head, so as to control the peak value of rock breaking resistance in a single operation and match the rock layer hardness to set the number of layers, so that the rock breaking resistance is always within a reasonable range of the equipment's bearing capacity. The excavation sequence is selected based on the development of rock joints and the stability of the surrounding rock: For rock strata with well-developed joints and poor surrounding rock stability, a top-down excavation sequence is adopted to utilize the self-weight of the upper rock strata to assist in pre-fracture; for hard rock with good integrity and high hardness, a bottom-up excavation sequence is adopted to avoid stress concentration in the top suspended area leading to collapse. Differentiated selection of excavation sequence optimizes the stress release path of the surrounding rock and improves the self-stability of the surrounding rock during the excavation process. By jointly setting constraints on the number of layers, layer thickness, and tunneling sequence, a unique combination of layered tunneling parameters corresponding to the rock hardness and joint characteristics is formed, completing the deterministic closed-loop configuration of the layered tunneling parameters for rectangular cross-sections. The joint constraints eliminate parameter coupling interference and ensure the repeatability of tunneling schemes under different rock conditions.

[0008] Preferably, S3 specifically includes: The operating parameters of the roller cutter head are set. The cutter head adopts a disc-shaped roller structure with a ring array arrangement. The disc-shaped rollers are arranged in an irregular array on the end face and outer periphery of the cutter head to form a multi-stage rock-breaking ring. The cutter head speed is set to 5~15 r / min and decoupled from the cantilever swing direction. The higher the hardness of the rock, the lower the speed value is, which improves the rock-breaking coverage and reduces the impact wear of the cutter. Establish a dual-parameter coordinated reduction rule for rock strength based on propulsion speed and penetration depth: for every 20MPa increase in the uniaxial compressive strength of the rock, the forced penetration depth is reduced by 1~2mm / r and the propulsion speed is reduced by 10%~20% simultaneously, forming a linkage reduction mapping relationship between propulsion speed and penetration depth to prevent equipment overload under hard rock conditions. Within a continuous range of 0.5 to 2.5 m / min, a unique combination of advance speed and penetration depth is dynamically locked based on the rock strength gradient, and the coupling selection of tunneling path and rock breaking sequence is completed simultaneously. This enables the rock stratum adaptive hard constraint calibration of tunneling machine operating parameters, achieving precise matching between operating parameters and geological conditions.

[0009] Preferably, S4 specifically includes: S4.1 Walking and positioning and machine stability: The whole machine walks to the working face to be excavated. The attitude is adjusted by the machine body tilt sensor and the laser guidance system to make the machine body coincide with the design center line of the roadway. The top support cylinder and the ground support cylinder are extended in stages and locked to complete the machine body anchoring and stabilization, ensuring the rigid anchoring of the machine body, suppressing rock breaking vibration and displacement, and ensuring the accuracy of the excavation point. S4.2 Layered Roller Excavation Operation: Following the preset two-column three-layer closed-loop excavation path, the rock breaking sequence is executed in a counterclockwise or clockwise direction. That is, the direction of the cutterhead swing is coupled in opposite directions with the direction of its rotation. When swinging to the left, it rotates clockwise and when swinging to the right, it rotates counterclockwise, forming a forced guiding effect that causes the rock debris to directionally gather towards the centerline of the cross-section. This enables the excavated soil to actively gather towards the centerline, improves loading efficiency, and alleviates the problem of debris accumulation at the edges and corners. S4.3, Tunnel support operation: Select the support mode according to the stability of the surrounding rock and the requirements of the unsupported roof. When the minimum unsupported roof distance is 6m, the tunneling and support synchronous mode is adopted. When the minimum unsupported roof distance is 4.2m, the advanced support mode is adopted for step-by-step operation to achieve the decoupling of the timing of tunneling and support, flexibly adapt to different surrounding rock conditions, realize the coordinated or step-by-step operation of tunneling and support, and ensure construction safety. S4.4 Cyclic Step Change: After completing the excavation and support of the current advance section, retract the top support cylinder and the ground support cylinder, and the whole machine moves forward to the next tunneling cycle working face position. Repeat steps S4.1 to S4.3 to achieve continuous tunneling, form a rigid time sequence closed loop, ensure the continuous and stable tunneling cycle, and improve work efficiency.

[0010] Preferably, in step S4.2, the specific process of the counterclockwise rock-breaking sequence is as follows: First cut: Control the cantilever to move the cutterhead to the left starting end of the second layer, and execute the first tunneling and rock breaking cycle according to the standardized action sequence of positioning-cutting-rolling rock breaking-cutting retraction-stepping, to ensure accurate positioning of the starting point and establish a benchmark for subsequent cycles; The second cut: The cutterhead swings horizontally to the right and advances to the right end of the layer to complete the second cut operation. During the process, the cutterhead rotates counterclockwise as it swings to the right, and the excavated soil gathers towards the middle of the tunnel, achieving one-time forming of half-width cross-section and improving the single-cut tunneling efficiency. The third cut: Control the cantilever to drive the cutterhead to move vertically upward by 1.08m (equivalent to 0.8 times the thickness of the cutterhead), move to the starting position of the first layer of excavation, complete the vertical positioning and rock breaking operation of the third cut, complete the precise positioning from the middle layer to the top layer, and ensure the accuracy of the layer connection. Fourth cut: Control the cantilever to drive the cutterhead to swing horizontally to the left from the right end of the layer. The cutterhead continues to rotate clockwise and tunnels to the starting end of the left side of the layer to complete the fourth cut. During the left swing of the cutterhead, the tangential force generated by the clockwise rotation will continuously push the rock debris towards the center line, forming a continuous debris diversion channel, covering the remaining width in the opposite direction, and eliminating the cumulative positioning error on one side. Fifth cut: Control the cantilever to drive the cutterhead to step downwards in the vertical direction. The step distance is set to 2m (covering the overall height difference between the first and third layers). Move to the starting position of the third layer excavation to complete the vertical layer replacement positioning and rock breaking operation of the fifth cut, realize the large span layer replacement from the top to the bottom layer, and complete the longitudinal full coverage. The sixth cut: The control arm drives the cutterhead to swing horizontally to the right from the starting end on the left side of the layer to the end on the right side of the layer, completing the sixth cut operation and forming a complete counterclockwise closed-loop tunneling path of "starting cutter from the lower left → tunneling to the right → moving up to the top → returning cutter to the left → moving down to the bottom → retracting cutter to the right". The six cuts close the loop, achieving full coverage of the rectangular cross-section without omission.

[0011] Preferably, the specific process of the clockwise rock-breaking sequence in S4.2 is as follows: First cut: Control the cantilever to move the cutterhead to the right starting end of the second layer, and perform the first tunneling and rock breaking cycle of positioning, cutting, rock breaking, cutting retraction, and stepping forward to ensure the accuracy of the starting point and lay the foundation for full-section forming; The second cut: The cutterhead swings horizontally to the left and advances to the left end of the layer to complete the second cut operation. During the process, the cutterhead rotates clockwise when it swings to the left, and the excavated soil gathers towards the middle of the tunnel. The swing direction is used to actively collect the excavated soil and reduce the loading burden. The third cut: Control the cantilever to drive the cutterhead to move vertically upward by 1.08m (equivalent to 0.8 times the thickness of the cutterhead), move to the first layer excavation position, complete the vertical positioning and rock breaking operation of the third cut, ensure accurate switching between layers, and avoid vertical coverage blind spots; Fourth cut: Control the cantilever to drive the cutterhead to swing horizontally to the right from the left end of the layer. The cutterhead continues to rotate counterclockwise and tunnels to the right end of the layer, completing the fourth cut operation. During the right swing of the cutterhead, the tangential force generated by the counterclockwise rotation will continuously push the rock debris towards the center line, forming a continuous debris flow channel. The reverse rotation coupled with the swing creates a continuous and stable flow mechanism. Fifth cut: Control the cantilever to drive the cutterhead to move vertically downward by 2m (covering the overall height difference between the first and third layers), move to the third layer excavation position, complete the vertical layer change positioning and rock breaking operation of the fifth cut, cross two layers at once, optimize the layer change path and improve efficiency; The sixth cut: The control arm drives the cutterhead to swing horizontally from the starting end on the right side of the layer to the left end of the layer, completing the sixth cut operation and forming a complete clockwise closed-loop tunneling path of "starting cutter on the lower right → tunneling to the left → moving up to the top → returning cutter to the right → moving down to the bottom → retracting cutter to the left". The closed-loop path is self-checked to ensure full coverage of the cross-section without omissions.

[0012] Preferably, the two-column three-layer closed-loop tunneling paths are controlled according to the following steps: The length of the two transverse excavations is set to be consistent with the design width of the rectangular roadway cross section, and the length of the transverse excavation of a single cutter is not less than half of the design width. The cumulative positioning error on one side in the width direction is eliminated by the alternating coverage of the double cutters. The cross section width direction forming accuracy is ensured by double cutter overlap verification to avoid over-excavation or under-excavation on one side. The vertical step distance is set to 0.6 to 0.9 times the diameter of the roller cutterhead, and the vertical overlap between adjacent layers is not less than 10% of the cutterhead diameter. By forcibly overlapping constraints, the tunneling blind zone between the layer interfaces is eliminated, ensuring continuous and uniform rock breaking across the entire cross section without any residual rock ridges. For the top and bottom corner areas of the rectangular cross-section, the vertical and horizontal step distances are halved independently, and the halved step distance does not exceed 0.45 times the diameter of the cutterhead. By locally increasing the step distance in the corner area, the under-excavated sharp corners and stress concentration areas in the right-angle area are eliminated, the under-excavated sharp corners in the right-angle area are eliminated, and a rounded transition profile is formed to improve the self-stability of the surrounding rock.

[0013] Preferably, in the rolling rock breaking process of S4.2, load threshold closed-loop energy control and active tool life management are performed according to the following steps: By using the tunneling machine's sensing system to monitor the instantaneous load of the cutterhead drive motor, the tunneling resistance of the cantilever propulsion cylinder, and the cumulative wear equivalent of the disc cutter in real time at a sampling frequency of no less than 10Hz, a three-parameter parallel monitoring link is established to control the interaction status between the equipment and the rock strata in real time and prevent sudden anomalies. When the cutterhead load exceeds 80% of the equipment's rated value, the cantilever propulsion speed and single-step penetration are automatically reduced based on the descending order mapping relationship corresponding to every 20MPa increase in the uniaxial compressive strength of the rock, until the load falls back to the safe hysteresis range of 60%~75% of the rated value, thus avoiding frequent load fluctuations, maintaining stable equipment stress, and extending the service life of core components. When the cumulative wear equivalent of the disc cutter reaches 90% of the preset replacement threshold, an early warning is triggered. When it reaches 100%, the machine is forced to stop and the cutter is replaced in batches. At the same time, the cumulative rock breaking volume of the replaced cutters is recorded to form a database of rock breaking volume corresponding to the unit cutter life. This database is used for parameter pre-calibration under the same rock strata conditions, improving the predictability of cutter replacement and continuously optimizing rock breaking parameters.

[0014] Preferably, the tunneling cycle operation of S4 is performed according to the following machine adaptation and advance control steps: The machine is a cantilevered hard rock rectangular section tunneling machine with an installed power of 1200kW and a power supply voltage of 3300V. Its roller cutterhead has a rated rock breaking capacity that can adapt to the maximum uniaxial compressive strength of rock up to 150MPa. By reducing the cutterhead speed to 5~8r / min and simultaneously lowering the penetration depth to 3~5mm / r, it can be locally adapted to 200MPa extremely hard rock conditions. This forms a three-level reduction adaptation rule of power-speed-penetration depth, ensuring that the equipment can still tunnel stably under extremely hard rock conditions without overload failure. The length of a single tunneling advance cycle unit is set to 1.5m. Within each cycle unit, four sub-steps are forcibly executed in sequence: walking and positioning and machine body stabilization, layered rolling excavation, roadway support, and cycle step change. It is forbidden to jump to the next cycle unit if any sub-step is not completed, forming a rigid time sequence closed loop of the advance unit to ensure that each cycle process is complete and orderly and to avoid omissions or chaos in the operation. The machine is compatible with a minimum rectangular cross-section of 5.2m×3.0m and a maximum rectangular cross-section of 6.5m×3.7m. The fixed diameter of the roller cutterhead is 3.5m. The layered coverage of the cutterhead in the cross-sectional height direction is achieved through the lifting and rotation mechanism of the cantilever. It is equipped with 4 anchor bolting machines to simultaneously execute the synchronous tunneling and support mode or the advanced support mode. The support capacity and the tunneling advance unit form a hard coupling constraint on the time axis, realizing the coordinated operation of tunneling and support, and improving the continuity and safety of construction.

[0015] Preferably, step S5 performs cross-sectional geometric accuracy acceptance and equipment closed-loop shutdown according to the following steps: After the tunnel excavation of the designed length is completed, the machine is controlled to retreat at a speed of no more than 3m / min to a safe area outside the tunnel entrance and at a distance of no less than 20m from the working face. All excavation, rotation and loading mechanisms are stopped, and the power output of the cutterhead drive motor is cut off to ensure that the retreat process is smooth and controlled, and to provide a safe isolation space for subsequent operations. The remaining rock debris on the working face is cleaned up by the shovel plate and loading mechanism. After cleaning, the cutter head and shovel plate area are rinsed with high pressure water. At the same time, the hydraulic system oil filtration test, the clearance calibration of the cantilever slewing bearing and the batch replacement of the disc cutter are carried out. The replaced cutter is torque-checked according to the initial installation torque to fully restore the equipment's tunneling performance and positioning accuracy and ensure reliability when restarting. A laser profile scanner is used to scan the entire cross-section of the completed roadway. The acceptance criteria are set as follows: the over-excavation of the cross-section does not exceed 100mm, there are no continuous under-excavation areas (continuous under-excavation is considered to be more than 200mm in length), the under-excavation of a single point does not exceed 50mm, and the curvature radius of the transition arc of the top and bottom corners deviates from the design value by no more than 15%. After all the test indicators meet the standards, a roadway forming quality acceptance report is issued, and the tunneling construction is completed. The forming quality is objectively evaluated with quantitative indicators to ensure that the cross-section meets the support and use requirements.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. This method of layered rolling rock breaking and forming for a cantilever hard rock rectangular section tunnel boring machine replaces the traditional cutting rock breaking mechanism with the rolling rock breaking mechanism of disc cutters. Through the combined action of static pressure crushing and rolling shearing, hard rock forms cracks and breaks rapidly under controllable load, which greatly improves the efficiency of single rock breaking. Combined with the layered tunneling process, the large section is decomposed into multiple small sections for excavation layer by layer, which effectively reduces the resistance of single rock breaking, improves the overall tunneling speed, and realizes efficient continuous tunneling of small and medium section rectangular hard rock tunnels.

[0017] 2. This layered rolling rock breaking and forming method for a cantilever hard rock rectangular section tunnel boring machine uses a roller cutter head to work in hard rock conditions by rolling, avoiding the severe impact and rapid wear caused by the cutting of the cutting teeth. The irregular array of roller cutters on the end face of the cutter head and the outer periphery forms a multi-level rock breaking ring, so that each roller cutter is subjected to uniform force and wear synchronously, extending the service life of a single operation. Combined with load adaptive control and wear threshold management, it avoids excessive wear or abnormal damage of the cutters, significantly reducing the frequency of cutter replacement and construction costs.

[0018] 3. This layered rolling rock breaking and forming method for a cantilever hard rock rectangular section tunnel boring machine adopts a two-column, three-layer closed-loop reciprocating tunneling path, combined with a counterclockwise or clockwise rock breaking sequence, to achieve layered coverage tunneling of the entire rectangular section. Through the alternating horizontal double-blade coverage and vertical overlapping gap elimination mechanism, it eliminates the cumulative positioning error and tunneling blind zone, ensuring the geometric accuracy of the section width and height. For the top and bottom corner areas, it adopts a dense stepping method to form a smooth transition arc, eliminate stress concentration, and improve the self-stability of the surrounding rock.

[0019] 4. This method of layered rolling rock breaking and forming for a cantilever hard rock rectangular section tunnel boring machine establishes a collaborative reduction rule for propulsion speed and penetration depth based on rock hardness. This allows the tunneling parameters to automatically adapt to changes in rock hardness, avoiding sudden load changes in hard rock conditions. By real-time monitoring of multiple parameters such as cutterhead load and tunneling resistance, the method automatically reduces the order of adjustment when the load exceeds the rated range, ensuring that the equipment always operates within a safe load range. This effectively suppresses impact and vibration, reduces equipment failure rate, and extends the service life of the entire machine. Attached Figure Description

[0020] Figure 1 This is an overall flowchart of the present invention; Figure 2 This is a schematic diagram of the overall structure of the present invention; Figure 3 This is a schematic diagram of the structure of the hobbing cutter head used in this invention. Figure 1 ; Figure 4 This is a schematic diagram of the structure of the hobbing cutter head used in this invention. Figure 2 ; Figure 5This is a schematic diagram of the single-step standardized tunneling operation process of the present invention; Figure 6 This is a schematic diagram of the closed-loop reciprocating cutting path planning for single-layer tunneling according to the present invention.

[0021] In the diagram: 1. Cutterhead; 2. Roller cutter; 3. Boom; 4. Front anchor bolting machine; 5. Electrical system; 6. Top support device; 7. Hydraulic system; 8. Rear anchor bolting machine; 9. Scraper conveyor; 10. Side support device; 11. Ground support device; 12. Traveling system; 13. Loading device; 14. Dust removal system. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0023] Example 1, please refer to Figures 1 to 6 This invention provides a technical solution: a layered rolling rock breaking and forming method for a cantilever hard rock rectangular section tunnel boring machine, comprising the following steps: S1. Geological Exploration and Rock Strata Analysis: Geological exploration is conducted on the rock strata of the tunnel to be excavated to obtain geological parameters of the target rock strata, including uniaxial compressive strength, Protodyakonov hardness f, rock stratum thickness, joint development, and surrounding rock stability. This provides a unique geological basis for setting stratification and operational parameters, achieving rock-excavation matching. In the geological exploration and rock strata analysis stage, a comprehensive geological survey is carried out on the rock strata of the tunnel to be excavated. Through core drilling and physical and mechanical testing of the surrounding rock, the uniaxial compressive strength, Protodyakonov hardness f, rock stratum thickness, and surrounding rock stability of the target rock strata are obtained. Core geological parameters such as the degree of joint development and the stability level of the surrounding rock are determined by combining on-site rock sampling and laboratory tests to measure the mechanical properties of the rock. At the same time, the distribution characteristics and dominant orientation of joints and fractures are analyzed in conjunction with the relationship between the tunnel direction and the rock strata. Based on the integrity coefficient of the surrounding rock and the rock mass quality grading standard, the self-stabilizing capacity of the surrounding rock and the adaptability range of the unsupported roof distance are comprehensively determined. The geological parameters obtained from the exploration serve as the sole basis for determining the subsequent layered tunneling parameters and setting the tunnel boring machine operating parameters, so as to achieve precise matching between the construction plan and the rock strata conditions. S2. Determination of Layering Parameters for Rectangular Cross-Sections: Based on the acquired geological parameters of the rock strata and the cross-sectional design dimensions of the target rectangular tunnel, the main layering excavation parameters of the cross-section are determined, including the number of main layers, the thickness of each main layer, and the excavation sequence. This forms a layering scheme uniquely corresponding to the rock strata characteristics, eliminating parameter coupling interference. The number of main layers is determined based on the acquired Protodyakonov hardness f: when f = 8~12, the number of main layers is 3~5; when f = 12~15, the number of main layers is 5~6; and when f > 15, the number of main layers is 6~8. The thickness of each layer does not exceed the thickness of the roller cutterhead to control the peak value of single rock-breaking resistance. The number of layers is set to match the rock strata hardness, ensuring that the rock-breaking resistance remains within a reasonable range of the equipment's bearing capacity. The selection of tunneling sequence is based on the development of rock joints and the stability of the surrounding rock: For rock strata with well-developed joints and poor surrounding rock stability, a top-down tunneling sequence is adopted to utilize the self-weight of the upper rock strata to assist in pre-fracture. For hard rock with good integrity and high hardness, a bottom-up tunneling sequence is adopted to avoid stress concentration in the top suspended area, which could lead to collapse. Differentiated selection of tunneling sequence optimizes the stress release path of the surrounding rock and improves the self-stability of the surrounding rock during tunneling. The number of layers, layer thickness, and tunneling sequence are jointly constrained to form a unique combination of layered tunneling parameters corresponding to the rock hardness and joint characteristics. This completes the deterministic closed-loop configuration of the layered tunneling parameters for rectangular cross-sections. The joint constraints eliminate parameter coupling interference and ensure the repeatability of tunneling schemes under different rock strata conditions. It should be noted that before actual tunneling, the number of main layers in the rectangular cross-section is directly determined based on the Protodyakonov hardness f obtained from geological exploration. When the Protodyakonov hardness f is between 8 and 12, the number of main layers is set to 3 to 5; when f is between 12 and 15, the number of main layers is set to 5 to 6; and when f is greater than 15, the number of main layers is set to 6 to 8. Simultaneously, the thickness of each single layer is limited to no more than the thickness of the roller cutterhead, thereby controlling the peak resistance of a single rock-breaking operation within the equipment's bearing capacity. Based on the determined number of layers, the corresponding tunneling sequence is selected according to the degree of joint development and the stability level of the surrounding rock. For rock strata with well-developed joints and poor surrounding rock stability, a top-down tunneling sequence is adopted, utilizing the self-weight of the upper rock strata to assist in pre-fracture, reducing the top rock-breaking resistance, and minimizing the impact of disturbance on unstable surrounding rock. For hard rock with good integrity and high hardness, a... The bottom-up tunneling sequence avoids premature stress concentration in the top overhanging area, which could lead to collapse. The two different tunneling sequences are selected to ensure the self-stability of the surrounding rock and construction safety during the tunneling process under different rock strata conditions, forming a sequence decision rule directly related to the rock strata characteristics. The number of layers, the thickness of a single layer, and the tunneling sequence are set as a set of joint constraint parameters and are systematically set. The three form an interlocking relationship. The number of layers determines the distribution of the thickness of a single layer in the cross-sectional height direction. The layer thickness further constrains the loading depth of the cutterhead in a single rock breaking. The tunneling sequence determines the temporal relationship between each layer and the stress release path of the surrounding rock. Through the joint configuration of each parameter, a layered tunneling parameter combination that uniquely corresponds to the rock hardness and joint characteristics is formed, completing the deterministic closed-loop configuration of the rectangular cross-section layered tunneling parameters, eliminating the coupling interference between parameters, and ensuring the repeatability and predictability of the tunneling scheme under different rock strata conditions. S3. Tunnel Boring Machine Operating Parameter Settings: Based on the main layer tunneling parameters and rock geological parameters, the operating parameters of the cantilever tunnel boring machine are set, including the rotation speed of the cutterhead, the swing speed and advance speed of the cantilever, the penetration depth of single-step tunneling, the selection of tunneling path and rock breaking sequence, establishing a deterministic mapping between rock strata and operating parameters, and achieving adaptive hard constraint calibration. The operating parameters of the cutterhead are set. The cutterhead adopts a disc cutter structure with a ring array arrangement, and the disc cutters are arranged in an irregular array on the end face and outer periphery of the cutterhead to form a multi-stage rock breaking ring. The cutterhead rotation speed is set to 5~15 r / min, decoupled from the swing direction of the cantilever. The higher the hardness of the hard rock, the lower the rotation speed value is, improving the rock breaking capacity. To improve coverage and reduce tool impact wear, a dual-parameter collaborative reduction rule for propulsion speed and penetration depth on rock strength is established: for every 20MPa increase in uniaxial compressive strength of rock, the forced penetration depth is reduced by 1~2mm / r and the propulsion speed is reduced by 10%~20% simultaneously, forming a linkage reduction mapping relationship between propulsion speed and penetration depth to prevent equipment overload under hard rock conditions. Within the continuous range of propulsion speed of 0.5~2.5m / min, a unique combination of propulsion speed and penetration depth is dynamically locked according to the rock strength gradient, and the coupling selection of tunneling path and rock breaking sequence is completed simultaneously, realizing the rock stratum adaptive hard constraint calibration of tunneling machine operating parameters and achieving precise matching between operating parameters and geological conditions. It should be noted that the operating parameters of the roller cutterhead are specifically calibrated based on the rock strata conditions. The main body of the cutterhead adopts a disc-shaped roller cutter structure arranged in a ring array, with irregular arrays on the end face and outer periphery of the cutterhead. This creates a multi-stage rock-breaking ring when the cutterhead rotates, allowing the roller cutters to act on the rock surface sequentially and in layers, increasing the rock-breaking coverage rate per unit rotation cycle. The rated speed of the cutterhead is set in stages within the range of 5–15 r / min. The higher the hardness of the rock, the lower the speed value is, to avoid abnormal wear of the roller cutters due to high-speed impact. At the same time, the cutterhead speed and the cantilever swing direction are decoupled, that is, the left and right swing of the cantilever and the rotation direction of the cutterhead are set independently to ensure a stable rolling rock-breaking state at different tunneling stages. The advance speed and penetration are based on a dual-parameter collaborative reduction rule established according to the uniaxial compressive strength of the rock. Specifically, for every 20 MPa increase in the uniaxial compressive strength of the rock, the single-step penetration is forcibly reduced by 1–2 mm / r. The axial advance speed of the cantilever is simultaneously reduced by 10% to 20%, and the two are adjusted in a fixed ratio to form a coordinated reduction-order mapping relationship between the advance speed and the penetration depth. This ensures that as the rock hardness increases, the depth of the cutter head cutting into the rock layer per revolution gradually decreases, while the forward advance speed of the cantilever is correspondingly slowed down. This avoids equipment overload caused by sudden changes in rock breaking resistance under hard rock conditions and ensures that the cutter head always works in the optimal mechanical range of static pressure crushing and rolling shearing. Based on the real-time rock strength gradient, a unique matching combination of advance speed and penetration depth is dynamically locked to achieve a one-to-one correspondence between the two parameters. On this basis, the coupling selection of the tunneling path and rock breaking sequence is completed simultaneously. That is, different combinations of advance speed and penetration depth correspond to preset counterclockwise or clockwise rock breaking sequences and corresponding closed-loop reciprocating tunneling paths. Through rock layer adaptive hard constraint calibration, the operating parameters of the tunneling machine can form a deterministic mapping relationship with the geological parameters before construction. S4. Tunneling Cycle Operation: After the cantilever tunneling machine is positioned and anchored, it performs layered rolling and rock breaking in a counterclockwise or clockwise manner according to a two-column, three-layer closed-loop path. The cutterhead rotates to assist in slag collection, with synchronous or step-by-step support. After changing steps, it cycles through tunneling to achieve full-coverage rolling and rock breaking and directional flow of slag, ensuring continuous tunneling. Specifically, this includes: S4.1. Traveling and Positioning and Machine Stability: The machine travels to the working face to be tunneled. The attitude is adjusted in coordination with the machine tilt sensor and laser guidance system to make the machine body coincide with the designed center line of the tunnel. The top support cylinder and ground support cylinder are extended in stages and locked to complete the machine body anchoring and stability, ensuring rigid anchoring of the machine body, suppressing rock breaking vibration and displacement, and ensuring accurate tunneling point positioning; S4.2. Layered Rolling Excavation Operation: According to the preset two-column, three-layer closed-loop tunneling path, the rock breaking sequence is executed in a counterclockwise or clockwise manner. That is, the direction of cutterhead swing is coupled in opposite directions to the direction of self-rotation. When swinging to the left... Clockwise rotation and counterclockwise rotation when swinging right create a forced flow effect that directs rock debris toward the centerline of the cross-section, enabling the excavated soil to actively gather toward the centerline, improving loading efficiency and alleviating the problem of debris accumulation at the edges and corners; S4.3, Tunnel support operation: Select the support mode according to the stability of the surrounding rock and the required unsupported distance. When the minimum unsupported distance is 6m, the synchronous tunneling and support mode is used, and when the minimum unsupported distance is 4.2m, the advanced support mode is used for step-by-step operation, realizing the temporal decoupling of tunneling and support, flexibly adapting to different surrounding rock conditions, realizing tunneling and support coordination or step-by-step operation, and ensuring construction safety; S4.4, Cyclic step change: After completing the cross-section excavation and support of the current advance, retract the top support cylinder and the ground support cylinder, and the whole machine moves forward to the position of the next tunneling cycle working face, repeating steps S4.1 to S4.3 to achieve continuous tunneling, forming a rigid temporal closed loop, ensuring continuous and stable tunneling cycle, and improving work efficiency; It should be noted that before the start of the tunneling cycle, the machine is positioned and stabilized. The operator controls the cantilever tunneling machine to slowly move to the working face via the tracked walking mechanism. As it approaches the working face, the machine's lateral and longitudinal tilt angles are monitored in real time using the machine tilt angle sensor. At the same time, the laser guidance system is activated to align and calibrate the machine's centerline with the designed centerline of the roadway until the deviation is controlled within the allowable range. After the attitude adjustment is completed, the top support cylinder and the ground support cylinder are operated in sequence according to the staged extension order to ensure that the top support device is tightly pressed against the roadway roof and the ground support device is stable. Supported by the base plate and with each hydraulic cylinder locked, a rigid anchor is formed between the machine body and the surrounding rock of the tunnel. This suppresses machine body vibration and displacement caused by cutterhead rotation and cantilever swing during subsequent rolling rock breaking, ensuring the positioning accuracy of each excavation point. After the machine body is anchored, layered rolling excavation operations begin. Following a pre-set two-column, three-layer closed-loop excavation path, the counterclockwise or clockwise rock breaking sequence is selected based on the rock strata conditions. The cantilever drives the roller cutterhead to perform layer-by-layer rock breaking. During the rock breaking process, the swing direction of the cutterhead is coupled in opposite directions to its rotation: when the cantilever drives the cutterhead to swing to the left, the cutterhead rotates clockwise. When the cutterhead swings to the right, it rotates counterclockwise. This reverse coupling control generates a forced flow guiding effect, causing the crushed rock debris to directionally converge towards the centerline of the cross-section under the action of rotational tangential force. This facilitates the collection and transfer of debris by the shovel section and star wheel loading mechanism located at the lower front of the machine body, improving the loading difficulties of debris accumulation in the corner areas of the cross-section under hard rock conditions and increasing the muck removal efficiency of continuous tunneling operations. Simultaneously or in stages, roadway support operations are carried out during layered rolling excavation. The specific support mode is determined based on the stability of the surrounding rock and the required unsupported roof distance. When the surrounding rock stability is good and the minimum unsupported roof distance can reach 6m, [further support is needed]. The tunneling and support are carried out in parallel, without taking up extra support time. When the surrounding rock joints are well developed, the stability is poor, and the minimum unsupported distance is tightened to 4.2m, the advanced support mode is adopted. The anchor bolter is extended to the front of the equipment to complete the support first before tunneling, so as to decouple the timing of tunneling and support. After the full-section excavation and support of the current advance are completed, the top support cylinder and the ground support cylinder are retracted, the machine body is released, and the whole machine is controlled to move forward to the position of the next cycle working face. The positioning, excavation and support steps are repeated to realize the continuous, stable and cyclic tunneling operation of rectangular hard rock roadways. S5. Section Forming and Finishing Operations: After completing the tunnel excavation of the designed length, the machine is moved to a safe area to complete the cleaning of the working face, equipment maintenance and repair, and tunnel forming quality acceptance. The tunneling construction is then completed, and the section accuracy is accepted using quantitative indicators to ensure that the geometric quality of the tunnel meets the usage requirements.

[0024] Example 2, as Figures 1 to 6As shown, based on Embodiment 1, the present invention provides a technical solution: In S4.2, the specific process of the counterclockwise rock breaking sequence is as follows: First cut: Control the cantilever to move the cutterhead to the left starting end of the second layer, and execute the first tunneling rock breaking cycle according to the standardized action sequence of positioning-cutting-rolling rock breaking-cutting retraction-stepping, ensuring accurate positioning of the starting point and establishing a benchmark for subsequent cycles; Second cut: The cutterhead swings horizontally to the right and tunnels to the right end of the layer, completing the second cut operation. During the process, the cutterhead itself rotates counterclockwise when swinging to the right, and the excavated soil gathers towards the middle of the roadway, achieving one-time forming of half-width cross-section and improving the single-cut tunneling efficiency; Third cut: Control the cantilever to move the cutterhead vertically upward by 1.08m (equivalent to 0.8 times the thickness of the cutterhead), moving to the starting position of the first layer tunneling, completing the vertical positioning and rock breaking operation of the third cut, completing the accurate positioning from the middle layer to the top layer, and ensuring the layer connection accuracy; Fourth cut: Control the cantilever to move the cutterhead from the right end of the layer, swinging horizontally to the left, and the cutterhead continues to maintain The cutterhead rotates clockwise, advancing to the starting point on the left side of the layer, completing the fourth cut. During the leftward swing of the cutterhead, the tangential force generated by the clockwise rotation continuously pushes the rock debris towards the centerline, forming a continuous debris flow channel. This channel covers the remaining width, eliminating accumulated positioning errors on one side. The fifth cut involves controlling the cantilever to move the cutterhead vertically downwards at a distance of 2 meters (covering the overall height difference between the first and third layers), moving to the starting position of the third layer, completing the fifth cut's vertical layer-changing positioning. Positioning and rock breaking operations enable large-span layer replacement from the top to the bottom, achieving full longitudinal coverage; the sixth cut: the control arm drives the cutterhead from the left starting end of the layer, swinging horizontally to the right end of the layer. During the process, the cutterhead rotates counterclockwise, causing the excavated soil to gather towards the middle of the tunnel, completing the sixth cut operation, forming a complete counterclockwise closed-loop tunneling path of "left lower cutter start → right tunneling → move up to the top → left cutter return → move down to the bottom → right cutter return". The six cuts close the loop, achieving full coverage of the rectangular cross-section without omission; It should be noted that when executing the counterclockwise rock breaking sequence, the cantilever first moves the roller cutterhead to the left starting point of the second layer. This starting point is located at the leftmost boundary point of the middle layer of the rectangular cross-section. After the cutterhead end face is fully in contact with the rock wall, the first tunneling rock breaking cycle is executed according to the standardized action sequence of positioning, cutting, rolling rock breaking, retraction, and stepping. During the positioning stage, the spatial position of the cutterhead is precisely adjusted by the rotation and lifting mechanism of the cantilever. During the cutting stage, the disc roller cutter is pressed into the rock wall to the set depth at a preset advance speed. Then, the cutterhead is driven to rotate to complete the cutterhead movement at that point. In the rolling rock breaking operation, the cutterhead retracts to detach from the already broken rock surface, avoiding abnormal cutter wear during movement. Finally, it advances to the next excavation point, completing the first cut. After the first cut, the cutterhead swings horizontally to the right to excavate to the right end of the layer, completing the second cut. During the rightward swing, the disc cutters continuously roll and break the rock layer, while the excavated soil naturally gathers towards the middle of the tunnel under the rotation of the cutterhead. Then, the cantilever is controlled to move the cutterhead vertically upward by 1.08 meters, a step distance equal to 0.8 times the thickness of the cutterhead, moving to... At the starting position of the first layer excavation, the third cutter head is used for vertical positioning and rock breaking. After vertical advancement, the cutterhead swings horizontally to the left from the right end of the layer, while continuing clockwise rotation. The fourth cutter head is then used to excavate to the left starting point of the layer. During the leftward swing, the tangential force generated by the clockwise rotation continuously pushes the rock debris towards the centerline, forming a continuous debris flow channel. After the fourth cutter head is completed, the cantilever arm is controlled to drive the cutterhead downwards vertically, with a step distance set at 2 meters. This distance covers the entire area between the first and third layers. The height difference between the layers causes the cutterhead to move to the starting position of the third layer of excavation, completing the vertical layer-changing positioning and rock-breaking operation of the fifth cutter. After the vertical layer-changing is in place, the cutterhead swings horizontally to the right from the starting end on the left side of the layer to the end on the right side of the layer, and performs the sixth cutter operation. This completes the closed-loop excavation cycle of the entire cross-section. The complete action sequence of this counterclockwise closed-loop path is: left lower cutter start, right excavation, move up to the top, left cutter return, move down to the bottom, and right cutter retraction. The six actions are connected in sequence to achieve full coverage rolling rock breaking of two rows of three-layer rectangular cross-sections, ensuring the accuracy of cross-section forming. In S4.2, the specific process of clockwise rock breaking sequence is as follows: First cut: Control the cantilever to move the cutterhead to the right starting end of the second layer, perform positioning-cutting-rock breaking-retraction-stepping the first tunneling rock breaking cycle, ensuring accurate starting point and laying the foundation for full-section forming; Second cut: The cutterhead swings horizontally to the left to tunnel to the left end of the layer, completing the second cut operation. During the process, the cutterhead rotates clockwise while swinging to the left, and the excavated soil gathers towards the middle of the roadway. The swing direction is used to actively collect the excavated soil, reducing the loading burden; Third cut: Control the cantilever to move the cutterhead vertically upward by 1.08m (equivalent to 0.8 times the thickness of the cutterhead), move to the first layer tunneling position, complete the vertical positioning and rock breaking operation of the third cut, ensure accurate switching between layers, and avoid vertical coverage blind spots; Fourth cut: Control the cantilever to move the cutterhead from the left end of the layer, swinging horizontally to the right, and the cutterhead maintains a counter-clockwise rotation. The clockwise rotation advances the cutterhead to the right-side starting point of the layer, completing the fourth cut. During the rightward swing of the cutterhead, the counter-clockwise rotation generates tangential force that continuously pushes the rock debris towards the centerline, forming a continuous debris flow channel. The reverse rotation coupled with the swing creates a continuous and stable flow mechanism. The fifth cut involves controlling the cantilever to move the cutterhead vertically downward by 2 meters (covering the overall height difference between the first and third layers), moving to the third layer's excavation position, completing the fifth cut's vertical layer-changing positioning and rock-breaking operation. This crosses two layer heights in one go, optimizing the layer-changing path and improving efficiency. The sixth cut involves controlling the cantilever to swing the cutterhead horizontally from the right-side starting point of the layer to the left-side end of the layer, completing the sixth cut. This forms a complete clockwise closed-loop excavation path of "right-downward cutterhead → leftward excavation → upward movement to the top → rightward cutterhead return → downward movement to the bottom → leftward cutterhead retraction." The closed-loop path self-checks to ensure full coverage of the cross-section without omissions. It should be noted that during the clockwise rock breaking sequence, the cantilever is first controlled to move the cutterhead to the right starting end of the second layer. After the cutterhead end face is fully in contact with the rock wall, a standardized sequence of actions is executed sequentially: positioning, cutting, rolling rock breaking, cutting retraction, and stepping, completing the first cutter rock breaking cycle. Subsequently, the cutterhead swings horizontally to the left to excavate to the left end of the layer, completing the second cutter operation. During the leftward swing of the cutterhead, the disc cutter continuously rolls and breaks the rock layer, while the excavated soil naturally gathers towards the middle of the tunnel under the action of the cutterhead rotation. After the second cut, the control arm moves the cutterhead vertically upwards by 1.08 meters. This step distance is 0.8 times the thickness of the cutterhead, allowing the cutterhead to accurately move to the starting position of the first layer of excavation, completing the vertical positioning and rock breaking operation of the third cut, ensuring precise coverage of the top section. After the third cut, the control arm moves the cutterhead horizontally to the right from the left end of the layer, while the cutterhead continues to rotate counterclockwise, excavating to the starting end of the right side of the layer, completing the fourth cut. During the rightward swing of the cutterhead, the tangential force generated by the counterclockwise rotation will... The rock debris is continuously pushed towards the centerline of the cross-section, forming a continuous debris flow channel. This allows the crushed rock debris to be directionally gathered towards the central area, facilitating collection and transfer by the shovel and star wheel loading mechanism. Without increasing additional energy consumption, this improves the loading difficulties of debris accumulation at the corners of the cross-section under hard rock conditions, enhances the muck removal efficiency of continuous tunneling operations, and reduces the amount of manual cleaning. After the fourth cut is completed, the cantilever is controlled to drive the cutterhead to step downwards vertically by 2 meters. This step distance covers the area between the first and third layers. The overall layer height difference allows the cutterhead to move to the starting position of the third layer of excavation, completing the vertical layer replacement and rock breaking operation of the fifth cutter. After the vertical layer replacement is in place, the cutterhead swings horizontally to the left from the starting end on the right side of the layer to the end on the left side of the layer to perform the sixth cutter operation. This forms a complete clockwise closed-loop excavation path of "starting cutter at the lower right → excavating to the left → moving up to the top → returning cutter to the right → moving down to the bottom → retracting cutter to the left". The six actions are connected in sequence to achieve full coverage rolling rock breaking of two rows of three-layer rectangular cross sections, ensuring that the cross section forming accuracy meets the design requirements. The two-column, three-layer closed-loop tunneling path is controlled according to the following steps: The length of the two transverse tunneling columns is set to be consistent with the design width of the rectangular tunnel cross-section, and the transverse tunneling length of a single cutter is not less than half the design width. Alternating double-cutter coverage eliminates the cumulative positioning error on one side in the width direction. Double-cutter overlap verification ensures the forming accuracy of the cross-section in the width direction, avoiding over- or under-excavation on one side. The vertical step distance is set to 0.6 to 0.9 times the diameter of the roller cutterhead, and the vertical overlap between adjacent layers is not less than the diameter of the cutterhead. 10%, by forcibly overlapping constraints to eliminate the tunneling blind zone between the layered interfaces, to ensure continuous and uniform rock breaking across the entire cross section, with no residual rock ridges. For the top and bottom corner areas of the rectangular cross section, the vertical step distance and the horizontal step distance are halved independently, and the halved step distance does not exceed 0.45 times the diameter of the cutterhead. By locally densifying the step distance in the corner area, the under-excavated sharp corners and stress concentration areas in the right-angle area are eliminated, forming a rounded transition profile and improving the self-stability of the surrounding rock. It should be noted that in actual tunneling operations, the length of the two transverse excavations is set to be consistent with the design width of the rectangular tunnel cross-section, and the length of a single transverse excavation is not less than half of the design width. Through a double-cutter alternating coverage excavation mode, after the first cutter completes rock breaking on one side in the horizontal direction, the second cutter covers the remaining width in the opposite direction, creating an overlap in the width direction for verification. This control strategy eliminates unilateral cumulative deviations caused by positioning errors of the cantilever rotary mechanism or the non-uniformity of the rock strata, ensuring that the forming accuracy in the width direction of the cross-section is always controlled within the design allowable range, avoiding subsequent support difficulties caused by over-excavation or under-excavation on one side. The vertical step distance is set according to 0.6 to 0.9 times the diameter of the roller cutterhead, while mandating that the vertical overlap between adjacent layers is not less than 10% of the cutterhead diameter. At the layer interface, the rock breaking area of ​​the subsequent cutter must partially cover the area already completed by the previous cutter. The boundary of the area forms an overlapping gap-eliminating mechanism. This overlapping constraint directly eliminates the tunneling blind zone that may be caused by errors in step distance calculation or positioning deviations of the cantilever lifting mechanism, ensuring that the rock strata between layers are completely broken and there are no continuous rock ridges that are not touched by the cutterhead, maintaining the continuity and uniformity of rock breaking along the entire cross-section height direction. For the top and bottom corner areas of the rectangular cross-section, the standard step distance is halved independently. The halved step distance does not exceed 0.45 times the diameter of the cutterhead. The top corner area adopts halved horizontal and vertical steps, so that the cutterhead performs multiple small-area coverage tunneling at the corner, gradually breaking the rock strata at the right-angle vertex into shape. The bottom corner area adopts the same densification strategy to avoid under-excavation of sharp corners left when the cutterhead cannot reach the farthest edge during large step tunneling. Through local densification of steps in the corner area, the four right-angle areas of the rectangular cross-section can form a smooth transition arc profile, eliminating stress concentration points and improving the self-stability of the surrounding rock. During the S4.2 rock-breaking process, load threshold closed-loop energy control and active tool life management are implemented according to the following steps: The tunneling machine's sensing system monitors the instantaneous load of the cutterhead drive motor, the tunneling resistance of the cantilever propulsion cylinder, and the cumulative wear equivalent of the disc cutterhead in real time at a sampling frequency of no less than 10Hz. A three-parameter parallel monitoring link is established to monitor the interaction between the equipment and the rock strata in real time, preventing sudden anomalies. When the cutterhead load exceeds 80% of the equipment's rated value, the load is automatically reduced based on the descending order mapping relationship corresponding to every 20MPa increase in the uniaxial compressive strength of the rock. The cantilever propulsion speed and single-step penetration are controlled until the load falls back to the safe hysteresis range of 60%~75% of the rated value to avoid frequent load fluctuations, maintain stable equipment stress, and extend the service life of core components. When the cumulative wear equivalent of the disc cutter reaches 90% of the preset replacement threshold, an early warning is triggered. When it reaches 100%, the machine is forced to stop and the cutter is replaced in batches. At the same time, the cumulative rock breaking volume of the replaced cutters is recorded to form a database of rock breaking volume corresponding to unit cutter life. This database is used for parameter pre-calibration under the same rock strata conditions, improves the predictability of cutter replacement, and continuously optimizes rock breaking parameters. It should be noted that a three-parameter parallel monitoring link is established through the tunneling machine's built-in sensing system. With a sampling frequency of no less than 10Hz, the instantaneous load of the cutterhead drive motor, the tunneling resistance of the cantilever propulsion cylinder, and the cumulative wear equivalent of the disc cutter are collected in real time. This data is synchronously uploaded to the tunneling machine's control system, forming a real-time joint monitoring of rock breaking status, equipment stress, and cutter life. This monitoring link continuously reflects the impact of changes in rock hardness on the equipment during tunneling, preventing a decrease in rock breaking efficiency or equipment damage due to abnormalities in a single parameter. When the cutterhead load exceeds 80% of the equipment's rated value, the control system automatically reduces the cantilever propulsion speed and single-step penetration in stages, based on the step-down mapping relationship corresponding to every 20MPa increase in the uniaxial compressive strength of the rock. The parameter adjustment adopts a stepped approach. The system employs a downward adjustment strategy until the cutterhead load falls back to the safe hysteresis range of 60% to 75% of the rated value before resuming normal tunneling. This effectively suppresses the impact of frequent load fluctuations on the cutterhead and cantilever system, avoiding equipment failures caused by overload in hard rock conditions. Simultaneously, it ensures that the cutterhead remains within a stable range of static pressure crushing and rolling shearing mechanics. For disc cutter wear management, the system accumulates the wear equivalent in real time and compares it with a preset replacement threshold. When the wear equivalent reaches 90% of the replacement threshold, the control system issues a warning, reminding operators to prepare for cutter replacement. When the wear equivalent reaches 100%, the system forces a shutdown and performs batch cutter replacement. After each cutter replacement, the system automatically records the accumulated rock-breaking volume of that batch of cutters from its initial use to replacement, forming a database of rock-breaking volume per unit cutter life. The S4 tunneling cycle operation is performed according to the following machine adaptation and advance control steps: A cantilever hard rock rectangular section tunneling machine with an installed power of 1200kW and a power supply voltage of 3300V is used. Its roller cutterhead has a rated rock breaking capacity adapted to a maximum uniaxial compressive strength of 150MPa. By reducing the cutterhead speed to 5~8r / min and simultaneously lowering the penetration rate to 3~5mm / r, it can be locally adapted to 200MPa extremely hard rock conditions. This forms a three-level reduction adaptation rule of power-speed-penetration rate, ensuring that the equipment can still tunnel stably without overload failure under extremely hard rock conditions. The length of a single tunneling advance cycle unit is set to 1.5m. Within each cycle unit, the machine is forced to sequentially perform walking positioning and machine stabilization... The process consists of four sub-steps: layered rolling excavation, tunnel support, and cyclical step-by-step operation. Jumping to the next cycle unit is prohibited until any sub-step is completed, forming a rigid time-sequence closed loop for the advance unit. This ensures the completeness and orderliness of each cycle, preventing omissions or confusion. The machine is compatible with a minimum rectangular cross-section of 5.2m × 3.0m and a maximum rectangular cross-section of 6.5m × 3.7m. The fixed diameter of the roller cutterhead is 3.5m. Layered coverage of the cutterhead in the cross-sectional height direction is achieved through the lifting and rotating mechanism of the cantilever. Four anchor bolting machines are used to simultaneously execute either synchronous tunneling and support mode or advanced support mode. The support capacity and the tunneling advance unit form a hard coupling constraint on the time axis, enabling coordinated tunneling and support operations and improving construction continuity and safety. The S5 machine is operated according to the following steps for cross-sectional geometric accuracy acceptance and closed-loop machine withdrawal: After completing the tunnel excavation of the designed length, the entire machine is controlled to withdraw at a withdrawal speed of no more than 3m / min to a safe area outside the tunnel entrance and at least 20m away from the working face. All excavation, rotation, and loading mechanisms are stopped, and the power output of the cutterhead drive motor is cut off to ensure a smooth and controlled withdrawal process, providing a safe isolation space for subsequent operations. The remaining rock debris on the working face is cleaned up by the shovel and loading mechanisms. After cleaning, the cutterhead and shovel areas are rinsed with high-pressure water. Simultaneously, the hydraulic system's oil filtration is tested, the clearance of the cantilever slewing bearing is calibrated, and the batch wear of the disc cutters is checked. Replace the cutter head with a torque check based on the initial installation torque to fully restore the equipment's tunneling performance and positioning accuracy, ensuring reliability during restart. Use a laser profile scanner to scan the entire cross-section of the completed tunnel. The acceptance criteria are set as follows: the over-excavation of the cross-section does not exceed 100mm, there are no continuous under-excavation areas (continuous length exceeding 200mm is considered continuous under-excavation), the single-point under-excavation does not exceed 50mm, and the curvature radius of the top and bottom corner transition arc deviates from the design value by no more than 15%. After all the test indicators meet the standards, a tunnel forming quality acceptance report is issued, and the tunneling construction ends. The forming quality is objectively evaluated with quantitative indicators to ensure that the cross-section meets the support and use requirements. It should be noted that after the designed length of tunnel excavation is completed, the operator should control the machine to retreat at a speed not exceeding 3 m / min until it is outside the tunnel entrance and at least 20 meters away from the working face. Upon reaching the designated location within the safety zone, all tunneling, rotating, and loading mechanisms are sequentially stopped, and the power output of the cutterhead drive motor is cut off to ensure the equipment is completely stationary. This shutdown and withdrawal process provides a safe working environment for subsequent cleaning, maintenance, and acceptance operations, preventing accidental equipment startup or rock debris falling and causing injury to personnel and equipment. After entering the safety zone, the remaining rock debris on the working face is centrally cleaned using the shovel and loading mechanisms. After cleaning, the cutterhead and shovel areas are rinsed with high-pressure water to remove adhering rock powder and debris. Simultaneously, hydraulic system oil filtration testing, cantilever slewing bearing clearance calibration, and batch replacement of worn disc cutters are carried out. The replaced cutters are strictly torque-checked according to the initial installation torque to ensure consistent preload for each cutter. The above maintenance operations fully restore the equipment's tunneling capacity and positioning accuracy, providing a reliable technical condition for the next tunneling cycle or equipment storage. After equipment maintenance, a laser profile scanner is used to perform a full-section contour scan of the completed roadway. The acceptance criteria are set as follows: over-excavation of the cross-section not exceeding 100 mm and no continuous length exceeding 200 mm. The continuous under-excavation area is mm, the single-point under-excavation amount does not exceed 50 mm, and the curvature radius of the top and bottom corner transition arc deviates from the design value by no more than 15%. After all the test indicators meet the standards, a roadway forming quality acceptance report is issued, and the tunneling construction is officially completed. This acceptance process is based on quantitative indicators to objectively evaluate the roadway forming quality and ensure that the cross-sectional geometric accuracy meets the requirements of subsequent support and use.

[0025] Example 3, as Figures 1 to 6 As shown, based on Examples 1 and 2, this invention provides a technical solution: Taking a hard rock tunnel excavation project in a metal mine as an example, according to the geological survey report of the mining area, the surrounding rock of the target tunnel is mainly skarnified dolomite marble, diopside skarn, garnet skarn, and igneous rocks. The highest uniaxial compressive strength of the rock is 241 MPa, and the Protodyakonov hardness is f8-12, with some local high-hardness areas reaching f20. The target tunnel has a rectangular cross-section with a designed cross-sectional area of ​​approximately 15.6 m². 2 (16m) 2 The tunnel is designed to be 1200m long, with moderate surrounding rock stability and a minimum unsupported roof distance of 4.2m. It can be adapted to synchronous support conditions with an unsupported roof distance of 6m. This embodiment uses the method of the present invention and is equipped with a 1200kW cantilever hard rock rectangular section tunneling machine. The core parameters of the equipment are: 3.5m diameter of the roller cutter head, rated speed of 5-15r / min, the maximum uniaxial compressive strength of the rock that the whole machine can adapt to is 150MPa, and it can be adapted to 200MPa conditions in some areas. It is equipped with 4 anchor bolting machines and has dual-mode support capability. The rated conveying capacity of the conveying system is 120m³ / h. The layered rolling rock breaking and forming method of the cantilever hard rock rectangular section tunnel boring machine in this embodiment specifically includes the following steps: Geological exploration and rock strata analysis, through advanced drilling and tunnel surrounding rock scanning, to obtain the core geological parameters of the target rock strata, the rock's Protodyakonov hardness is f8-12, and in some igneous rock areas it can reach about f20, corresponding to a uniaxial compressive strength of 80MPa-241MPa, the overall integrity of the rock strata is good, local joints are developed, the surrounding rock stability is moderate, and there are no large faults or fracture zones; the main layering parameters of the cross section are determined based on the target rock strata's hardness parameter of f8-12, combined with a 3.0m tunnel... The cross-sectional height is determined by the number of main layers in the cross-section being 3, with a single main layer thickness of 1m and a cutterhead thickness less than 1.35m for each layer. Based on the integrity and hardness characteristics of the rock strata, a clockwise or counterclockwise excavation sequence is adopted to achieve layer-by-layer tunneling. Simultaneously, the cutterhead rotates clockwise. When the excavation sequence is counterclockwise, the cutterhead rotates clockwise, starting the first excavation cycle from the left end of the middle layer of the cross-section, causing rock debris to converge towards the middle of the cross-section. Similarly, when the excavation sequence is clockwise, the cutterhead rotates counterclockwise, starting the first excavation cycle from the right end of the middle layer of the cross-section, causing rock debris to converge towards the middle of the cross-section. The tunnel boring machine (TBM) is designed to be concentrated in the middle of the face for easy loading and transportation of excavated soil. The operating parameters are set according to the main strata parameters and the geological parameters of the rock strata. The rated speed of the roller cutterhead is set to 8 r / min, with the speed reduced to 5 r / min in the high-hardness (F20) areas. The axial advance speed of the cantilever is set to 1.2 m / min, reduced to 0.8 m / min in the high-hardness areas. The single-step cutting penetration is set to 8 mm / r, reduced to 5 mm / r in the high-hardness areas. Based on the tunnel cross-section dimensions, a two-column, three-layer closed-loop tunneling path is selected, with either counter-clockwise or clockwise rock breaking sequence. Vertical steps... The advance distance is set to 1.08m (0.8 times the cutterhead thickness); the tunneling cycle operation is carried out in 1.5m increments, following standardized operating procedures. For positioning and machine stability, the tracked walking mechanism of the tunneling machine is controlled to move the entire machine to the working face to be excavated. The machine's level is adjusted using a body tilt sensor to ensure that the machine body coincides with the designed centerline of the roadway, with a lateral horizontal error not exceeding 3%. The first two sets of anchor bolting machines and the last two sets of anchor bolting machines extending from the machine body complete the anchoring and stabilization of the machine body, preventing vibration and displacement during rock breaking; the rolling excavation operation begins from the middle left end, as... Figure 6 The rolling rock breaking operation is performed according to the preset counterclockwise rock breaking sequence. The specific process is as follows: First cut: Control the cantilever to move the cutterhead to the left starting end of the second layer, and perform the first tunneling and rock breaking cycle: positioning, cutting advance, rock breaking, cutting retraction, and stepping forward. Second cut: The cutterhead swings horizontally to the right and advances to the right end of the layer to complete the second cut operation. During the process, when the cutterhead swings to the right, the excavated soil gathers towards the middle of the tunnel. Third cut: Control the cantilever to drive the cutterhead to move vertically upward by 1.08m to the first layer excavation position, and complete the third cut operation; Fourth cut: Control the cantilever to drive the cutterhead to swing horizontally to the left from the right end of the layer to the starting end of the left side of the layer, completing the fourth cut operation. During the process, the cutterhead swings to the left and rotates clockwise, and the excavated soil continues to gather towards the middle. Fifth cut: Control the cantilever to drive the cutterhead to move vertically downwards by 2m to the third layer excavation position, completing the fifth cut operation; The sixth cut: Control the cantilever to drive the cutterhead to swing horizontally to the right from the starting end on the left side of the layer to the end on the right side of the layer, completing the closed-loop tunneling cycle of the sixth cut operation; Similarly, the rolling rock breaking operation is performed according to the preset clockwise rock breaking sequence. The specific process is as follows: First cut: Control the cantilever to move the cutterhead to the right starting end of the second layer, and perform the first tunneling and rock breaking cycle: positioning, cutting, rock breaking, cutting retraction, and stepping forward. Second cut: The cutterhead swings horizontally to the left to excavate to the left end of the layer, completing the second cut excavation operation; The third cut: control the cantilever to drive the cutterhead to step vertically upward to the first layer of excavation position, and complete the positioning calibration and excavation rock breaking operation of the third cut; Fourth cut: Control the cantilever to drive the cutterhead to swing horizontally to the right from the left end of the layer and excavate to the right starting end of the layer, completing the fourth cut excavation operation; Fifth cut: Control the cantilever to drive the cutterhead to step vertically downward to the third layer of excavation position, and complete the positioning calibration and rock breaking operation of the fifth cut; The sixth cut: The control arm drives the cutterhead to swing horizontally from the right starting end of the layer to the left end of the layer, and the sixth cut is made to complete the closed-loop tunneling cycle of the section.

[0026] For the layered top and bottom corner areas, a half-step distance is used for refined tunneling to form a smooth transition arc and ensure the accuracy of the cross-section. During operation, the cutterhead load is monitored in real time. When the cutterhead load in a local F20 high-hardness area exceeds 80% of the rated value, the advance speed and penetration depth are automatically reduced to ensure equipment safety. For roadway support operations, based on the moderate stability characteristics of the surrounding rock, a simultaneous tunneling and support mode is adopted in normal rock strata sections. Under a 6m unsupported roof distance, tunneling operations are carried out simultaneously through four anchor bolting machines attached to the machine body, without occupying separate operation time. In areas with well-developed joints and poor surrounding rock stability, an advanced support mode is adopted, extending the anchor bolting machines in front of the equipment and carrying out support operations under a minimum unsupported roof distance of 4.2m. After the support is completed... Continue with subsequent excavation, ensuring construction safety; cycle through the steps, and after completing the full-section excavation and support work for the current 1.5m advance, retract the top support cylinder and ground support cylinder, and release the machine body anchorage; control the whole machine to move forward 1.5m to the position of the next cycle working face, and repeat the above steps to achieve continuous tunnel excavation; rectangular section forming and finishing work: after completing the tunnel excavation of the designed length of 1200m, control the whole machine to retreat to the safe area at the tunnel entrance, and complete the work face cleaning, equipment maintenance and cutter wear replacement; use a laser section scanner to inspect the tunnel forming quality. The inspection results show that: the maximum over-excavation of the tunnel section is 85mm, there is no continuous under-excavation, the maximum under-excavation at a single point is 40mm, the transition arc of the top and bottom corners is smooth, the tunnel outline fully meets the design requirements, and there is no obvious disturbance to the surrounding rock; This embodiment achieves stable and efficient tunneling in extremely hard rock of grade f8-f15, and locally f20, using the method of the present invention, targeting a depth of 16m. 2 With a rectangular cross-section, the average excavation speed can reach 15m. 3 With a daily stable advance of 8-12m, compared to conventional cutting tooth tunneling machines, it reduces tool wear by 80%, increases tunneling efficiency by 150%, produces excellent tunnel formation quality, and has good surrounding rock self-stability, perfectly meeting the tunneling construction needs of small-section hard rock tunnels in metal mines.

[0027] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. The scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A layered rolling rock breaking and shaping method for a cantilever hard rock rectangular section tunnel boring machine, characterized in that, Includes the following steps: S1. Geological exploration and rock strata analysis: Conduct geological exploration of the rock strata of the tunnel to be excavated to obtain geological parameters of the target rock strata, including uniaxial compressive strength, Protodyakonov hardness f, rock strata thickness, joint development and surrounding rock stability. S2. Determination of Rectangular Cross-Section Layering Parameters: Based on the obtained geological parameters of the rock strata and combined with the cross-sectional design dimensions of the target rectangular tunnel, determine the main layering excavation parameters of the cross-section, including the number of main layers, the thickness of a single main layer, and the excavation sequence. S3. Setting the operating parameters of the tunneling machine: Based on the main layer tunneling parameters and the geological parameters of the rock strata, set the operating parameters of the cantilever tunneling machine, including the rotation speed of the cutterhead, the swing speed and advance speed of the cantilever, the penetration depth of single-step tunneling, and the selection of tunneling path and rock breaking sequence. S4. Tunneling Cycle Operation: After the cantilever tunneling machine is in place and anchored, it rolls and breaks the rock in two rows of three-layer closed loop paths in a counterclockwise or clockwise manner. The cutterhead rotates to assist in slag collection, and supports the machine synchronously or in stages. After changing stages, the tunneling is carried out in a cycle. S5. Section Forming and Finishing Operations: After completing the tunnel excavation of the designed length, the entire machine is moved to a safe area to complete the cleaning of the working face, equipment maintenance and repair, and tunnel forming quality acceptance, thus ending the tunneling construction.

2. The layered rolling rock breaking and shaping method for a cantilever hard rock rectangular section tunnel boring machine according to claim 1, characterized in that: S2 specifically includes: The number of main layers is determined based on the obtained Protodyakonov hardness f: when f=8~12, the number of main layers is 3~5 layers; when f=12~15, the number of main layers is 5~6 layers; when f>15, the number of main layers is 6~8 layers, and the thickness of a single layer does not exceed the thickness of the roller cutter head, so as to control the peak value of rock breaking resistance in a single operation. The excavation sequence is selected based on the development of rock joints and the stability of the surrounding rock: for rock strata with well-developed joints and poor surrounding rock stability, an excavation sequence from top to bottom is adopted; for hard rock with good integrity and high hardness, an excavation sequence from bottom to top is adopted. By jointly constraining the number of layers, layer thickness, and tunneling sequence, a unique combination of layered tunneling parameters corresponding to the rock hardness and joint characteristics is formed, thus completing the deterministic closed-loop configuration of the layered tunneling parameters for rectangular cross-sections.

3. The layered rolling rock breaking and shaping method for a cantilever hard rock rectangular section tunnel boring machine according to claim 1, characterized in that: S3 specifically includes: The operating parameters of the roller cutter head are set. The cutter head adopts a disc-shaped roller structure with a ring array arrangement. The disc-shaped rollers are arranged in an irregular array on the end face and outer periphery of the cutter head to form a multi-stage rock breaking ring. The cutter head speed is set to 5~15 r / min and decoupled from the cantilever swing direction control. Establish a dual-parameter coordinated reduction rule for rock strength based on propulsion speed and penetration depth: for every 20MPa increase in the uniaxial compressive strength of rock, the forced penetration depth decreases by 1~2mm / r and the propulsion speed decreases by 10%~20% simultaneously, forming a linkage reduction mapping relationship between propulsion speed and penetration depth. Within a continuous range of 0.5 to 2.5 m / min, a unique combination of advance speed and penetration depth is dynamically locked based on the rock strength gradient, and the coupling selection of tunneling path and rock breaking sequence is completed simultaneously, thereby realizing the rock stratum adaptive hard constraint calibration of tunneling machine operating parameters.

4. The layered rolling rock breaking and shaping method for a cantilever hard rock rectangular section tunnel boring machine according to claim 1, characterized in that: S4 specifically includes: S4.1 Walking and positioning and machine body stabilization: The whole machine walks to the working face to be excavated, and adjusts its posture in coordination with the machine body tilt angle sensor and laser guidance system to make the machine body coincide with the design center line of the roadway. The top support cylinder and the ground support cylinder are extended in stages and locked to complete the anchoring and stabilization of the machine body. S4.2 Layered rolling excavation operation: According to the preset two-column three-layer closed-loop tunneling path, the rock breaking sequence is executed in a counterclockwise or clockwise direction. That is, the direction of the cutterhead swing is coupled in the opposite direction to the direction of its rotation. When swinging to the left, it rotates clockwise and when swinging to the right, it rotates counterclockwise, forming a forced flow effect that causes the rock debris to directionally converge towards the centerline of the cross section. S4.3, Tunnel support operation: Select the support mode according to the stability of the surrounding rock and the requirements of the unsupported roof. When the minimum unsupported roof distance is 6m, the tunneling and support synchronous mode is adopted, and when the minimum unsupported roof distance is 4.2m, the advanced support mode is adopted for step-by-step operation. S4.4, Cyclic Step Change: After completing the excavation and support of the current advance section, retract the top support cylinder and the ground support cylinder, and the whole machine moves forward to the position of the next tunneling cycle working face. Repeat steps S4.1 to S4.3 to achieve continuous tunneling.

5. The layered rolling rock breaking and shaping method for a cantilever hard rock rectangular section tunnel boring machine according to claim 4, characterized in that: In S4.2, the specific process of the counterclockwise rock breaking sequence is as follows: First cut: Control the cantilever to move the cutterhead to the left starting end of the second layer, and execute the first tunneling and rock breaking cycle according to the standardized action sequence of positioning-cutting-rolling rock breaking-cutting retraction-stepping; Second cut: The cutterhead swings horizontally to the right and advances to the right end of the layer to complete the second cut operation. During the process, the cutterhead itself rotates counterclockwise as it swings to the right, and the excavated soil gathers towards the middle of the tunnel. The third cut: control the cantilever to drive the cutterhead to move vertically upward by 1.08m, move to the starting position of the first layer of tunneling, and complete the vertical positioning and rock breaking operation of the third cut; Fourth cut: Control the cantilever to drive the cutterhead to swing horizontally to the left from the right end of the layer. The cutterhead continues to rotate clockwise. Excavate to the starting end of the left side of the layer to complete the fourth cut. During the left swing of the cutterhead, the tangential force generated by the clockwise rotation will continuously push the rock debris towards the center line, forming a continuous debris flow channel. Fifth cut: Control the cantilever to drive the cutterhead to step downwards in the vertical direction, with a step distance set at 2m, and move to the starting position of the third layer of excavation to complete the vertical layer change positioning and rock breaking operation of the fifth cut; The sixth cut: Control the cantilever to drive the cutterhead from the starting end on the left side of the layer to the right side of the layer, completing the sixth cut and forming a complete counterclockwise closed-loop tunneling path.

6. The layered rolling rock breaking and shaping method for a cantilever hard rock rectangular section tunnel boring machine according to claim 4, characterized in that: In S4.2, the specific process of the clockwise rock-breaking sequence is as follows: First cut: Control the cantilever to move the cutterhead to the right starting end of the second layer, and perform the first tunneling and rock breaking cycle: positioning, cutting, rock breaking, cutting retraction, and stepping forward. Second cut: The cutterhead swings horizontally to the left and advances to the left end of the layer to complete the second cut operation. During the process, the cutterhead rotates clockwise when it swings to the left, and the excavated soil gathers in the middle of the tunnel. The third cut: control the cantilever to drive the cutterhead to move vertically upward by 1.08m, move to the first layer of excavation position, and complete the vertical positioning and rock breaking operation of the third cut; Fourth cut: Control the cantilever to drive the cutterhead to swing horizontally to the right from the left end of the layer. The cutterhead continues to rotate counterclockwise. Excavate to the right end of the layer to complete the fourth cut. During the right swing of the cutterhead, the tangential force generated by the counterclockwise rotation will continuously push the rock debris towards the center line, forming a continuous debris flow channel. Fifth cut: Control the cantilever to drive the cutterhead to step vertically downwards by 2m, move to the third layer excavation position, and complete the vertical layer change positioning and rock breaking operation of the fifth cut; The sixth cut: Control the cantilever to drive the cutterhead from the starting end on the right side of the layer to the left side of the layer, completing the sixth cut and forming a complete clockwise closed-loop tunneling path.

7. The layered rolling rock breaking and shaping method for a cantilever hard rock rectangular section tunnel boring machine according to claim 4, characterized in that: The two-column, three-layer closed-loop tunneling paths are controlled according to the following steps: The length of the two transverse excavations is set to be consistent with the design width of the rectangular roadway cross section, and the length of the single-blade transverse excavation is not less than half of the design width. The cumulative positioning error on one side in the width direction is eliminated by the double blades alternatingly covering. The vertical step distance is set to 0.6 to 0.9 times the diameter of the roller cutterhead, and the vertical overlap between adjacent layers is not less than 10% of the cutterhead diameter. The tunneling blind zone between the layer interfaces is eliminated by forced overlap constraint. For the top and bottom corner areas of the rectangular cross-section, the vertical and horizontal step distances are halved independently, and the halved step distance does not exceed 0.45 times the diameter of the cutterhead. The under-excavation of sharp corners and stress concentration areas in the right-angle areas is eliminated by locally increasing the step distance in the corner areas.

8. The layered rolling rock breaking and shaping method for a cantilever hard rock rectangular section tunnel boring machine according to claim 4, characterized in that: During the rolling rock breaking process in S4.2, load threshold closed-loop energy control and active tool life management are performed according to the following steps: The instantaneous load of the cutterhead drive motor, the tunneling resistance of the cantilever propulsion cylinder, and the cumulative wear equivalent of the disc cutter are monitored in real time by the tunneling machine's sensing system at a sampling frequency of no less than 10Hz, and a three-parameter parallel monitoring link is established. When the cutterhead load exceeds 80% of the equipment's rated value, the cantilever propulsion speed and single-step penetration are automatically reduced based on the descending mapping relationship corresponding to every 20MPa increase in the uniaxial compressive strength of the rock, until the load falls back to the safe hysteresis range of 60%~75% of the rated value. When the cumulative wear equivalent of the disc cutter reaches 90% of the preset replacement threshold, an early warning is triggered. When it reaches 100%, the machine is forced to stop and the cutter is replaced in batches. At the same time, the cumulative rock breaking volume of the replaced cutters is recorded to form a database of rock breaking volume corresponding to the unit cutter life.

9. The layered rolling rock breaking and shaping method for a cantilever hard rock rectangular section tunnel boring machine according to claim 1, characterized in that: The tunneling cycle operation of S4 is performed according to the following machine adaptation and advance control steps: The cantilever hard rock rectangular section tunneling machine with an installed power of 1200kW and a power supply voltage of 3300V is adopted. Its roller cutterhead has a rated rock breaking capacity that can adapt to the maximum uniaxial compressive strength of rock up to 150MPa. By reducing the cutterhead speed to 5~8r / min and simultaneously reducing the penetration to 3~5mm / r, it can be locally adapted to the 200MPa extremely hard rock working condition, forming a three-level reduction adaptation rule of power-speed-penetration. The length of a single tunneling advance cycle unit is set to 1.5m. Within each cycle unit, four sub-steps are forcibly executed in sequence: walking and positioning and machine body stabilization, layered rolling excavation, roadway support, and cycle step change. Jumping to the next cycle unit is prohibited if any sub-step is not completed. The machine is compatible with a minimum rectangular cross-section of 5.2m×3.0m and a maximum rectangular cross-section of 6.5m×3.7m. The fixed diameter of the roller cutterhead is 3.5m. The layered coverage of the cutterhead in the cross-sectional height direction is achieved through the lifting and rotating mechanism of the cantilever. It is equipped with 4 anchor bolting machines to simultaneously execute the synchronous tunneling support mode or the advanced support mode.

10. The layered rolling rock breaking and shaping method for a cantilever hard rock rectangular section tunnel boring machine according to claim 1, characterized in that: The S5 process performs cross-sectional geometric accuracy acceptance and closed-loop equipment shutdown according to the following steps: After completing the tunnel excavation of the designed length, control the machine to retreat to a safe area outside the tunnel entrance and at a speed of no more than 3m / min, and at a distance of no less than 20m from the working face. Stop all excavation, rotation and loading mechanisms, and cut off the power output of the cutterhead drive motor. The remaining rock debris on the working face is cleaned up by the shovel plate and loading mechanism. After cleaning, the cutter head and shovel plate area are rinsed with high pressure water. At the same time, the hydraulic system oil filtration test, the clearance calibration of the cantilever slewing bearing and the batch wear replacement of the disc cutter are carried out. The replaced cutter is torque verified according to the initial installation torque. A laser profile scanner is used to scan the full profile of the completed tunnel. The acceptance criteria are set as follows: the over-excavation of the cross section does not exceed 100mm, there are no continuous under-excavation areas, the under-excavation of a single point does not exceed 50mm, and the curvature radius of the top and bottom corner transition arc deviates from the design value by no more than 15%. After all the test indicators meet the standards, a tunnel forming quality acceptance report is issued, and the tunneling construction is completed.

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