Plateau alpine tunnel deep-buried central ditch milling and digging tool and construction method

Abstract

The invention relates to the technical field of tunnel engineering construction, in particular to a milling and excavating tool for a deep-buried central ditch of a plateau high and cold tunnel and a construction method.The tool comprises a self-propelled inverted arch trestle and a deep-buried ditch milling and excavating system, a rail is arranged on the self-propelled inverted arch trestle, and the deep-buried ditch milling and excavating system comprises a walking trolley and a milling and excavating machine; the walking trolley is movably arranged on the track and is driven by the driving device to walk along the track, the milling excavator is installed below the walking trolley through the rigid connecting mechanism, and the construction method comprises the steps that after inverted arch curvature excavation forming is conducted, the tool is used for accurately milling and excavating a ditch groove with the straight line shape and the ditch width consistent with the ditch bottom drainage gradient along the center line of a tunnel; according to the construction method, the problems of large position deviation, non-straight line type, inconsistent drainage gradient of the ditch bottom and the like of the center deeply-buried ditch in traditional excavator construction are solved, and the construction method has the advantages of high construction precision, high efficiency, low cost and the like.

Description

Technical Field

[0001] This invention relates to the field of tunnel engineering construction technology, specifically to a milling tool and construction method for deep-buried central drainage ditches in high-altitude and cold-climate tunnels. Background Technology

[0002] In tunnel construction in high-altitude and frigid regions, deeply buried central drainage ditches are crucial structures for draining groundwater and preventing tunnel frost damage. Currently, excavators are commonly used for excavating these ditches. However, this traditional method has significant drawbacks: First, excavator operation is greatly affected by the driver's line of sight and operating habits, resulting in trenches that are not centered on the invert arch and are not perfectly straight. This causes the deep-buried drainage ditch to be positioned outside the center of the encasing concrete and top graded crushed stone filter layer, leading to significant thickness variations in the filter layer on both sides and severely impacting its filtration and drainage function. Second, the uneven elevation of the trench bottom excavated by excavators not only requires manual adjustment but also wastes subsequent bottom concrete, increasing construction costs. In the harsh environment of high-altitude and frigid regions, manual adjustment is inefficient and difficult, making these problems particularly pronounced. Therefore, there is an urgent need for a more efficient and precise construction equipment and process. Summary of the Invention

[0003] The problem to be solved by the present invention is to provide a milling tool and construction method for deep buried central drainage ditches in high-altitude and cold-climate tunnels, so as to solve the problems of large deviation in the construction position of drainage ditches, non-straight lines, uneven bottoms, low construction efficiency and high costs in the prior art.

[0004] To address the shortcomings of existing technologies, the technical solution adopted by this invention is as follows: a milling tool for constructing deep-buried central drainage ditches in high-altitude and cold-climate tunnels, comprising a self-propelled arch bridge and a deep-buried drainage ditch milling system. The self-propelled arch bridge is equipped with a track. The deep-buried drainage ditch milling system includes a traveling trolley and a milling machine. The traveling trolley is movably mounted on the track and is driven by a drive device to travel along the track. The milling machine is installed below the traveling trolley via a rigid connection mechanism. A protective baffle to prevent flying debris is welded to the lower part of the traveling trolley, and the protective baffle is located on the side of the milling machine.

[0005] Preferably, the traveling trolley includes a movable frame and traveling wheels disposed on the movable frame, the traveling wheels cooperating with a track, and the driving device includes a drive motor, which is connected to the traveling wheels in a transmission manner.

[0006] Preferably, the rigid connection mechanism includes two channel steels and a crossbar. The two channel steels are fixedly mounted on the movable frame. The crossbar passes through the body of the milling machine, and both ends of the crossbar are connected to the channel steels. The two ends of the body of the milling machine are also provided with limiting devices to restrict its lateral displacement.

[0007] Preferably, the limiting device includes a high-strength bolt and two reinforcing iron plates. The crossbar has mounting holes, the high-strength bolt passes through the mounting holes and the reinforcing iron plates, and the two reinforcing iron plates are detachably connected.

[0008] Preferably, the crushing track of the milling machine is made of artificial diamond saw blade, and the length of the crushing track is 3500-3800mm and the width is 2000-2500mm.

[0009] Preferably, the traveling trolley has a length of 1800-2200mm, a width of 500-700mm, and a maximum travel distance of 12000-15000mm.

[0010] Preferably, the protective baffle is made of steel plate with a thickness of 8-12mm, a length of 1400-1600mm, and a width of 1500-1700mm.

[0011] A construction method for a milling tool used in the construction of deep-buried central drainage ditches in high-altitude and cold-climate tunnels includes the following steps: S1: Excavate and shape the arch curvature to form the working surface required for ditch construction; S2: Determine the construction speed and efficiency of the milling machine, drive the traveling trolley, and move the milling machine along the track of the self-propelled arch bridge from the closed end of the upper plate to the working face to carry out milling and excavation of the deep buried central water ditch. S3: The milling machine stops excavating after excavating a predetermined length; S4: Install the prefabricated drainage ditch base and adjust its slope; S5: Install prefabricated water pipes on the ditch base with the adjusted slope; S6: Backfill the middle section with C25 concrete to the design elevation; S7: After the C25 concrete in the middle has set and reached its strength, backfill the top of the precast water pipe with graded crushed stone, and cover the top of the graded crushed stone with geotextile to prevent the initial support concrete from entering the crushed stone layer and causing it to harden, thus affecting the drainage function. S8: Install the initial support steel frame for the invert arch and spray initial support concrete; S9: Repeat steps S2 to S8 until the construction length of the initial support section of the invert arch reaches the length of one invert arch lining plate. S10: The mobile self-propelled arch bridge 1 will proceed with the construction of the next arch section.

[0012] Preferably, in step S2, the construction speed A of the milling machine is set or dynamically adjusted according to the formula A=a-5×[(H-0.5) / 0.5]-5×[(S-1) / 1]=a-5×[(H-0.5) / 0.5+(S-1)]=a-5×[H / 0.5+S-2)]. Where A is the construction rotation speed (r / min), a is the theoretical rotation speed selected based on the strength of the surrounding rock, H is the milling depth (m), and S is the contact area between the milling head and the surrounding rock (m²). The construction efficiency Q of the milling machine is calculated according to the formula Q=D×W×V×60×η; Where Q is efficiency (m³ / h), which refers to the effective volume of material actually removed per hour, D is cutting depth (m), W is cutting width (m), V is advancing speed (m / min), and η is time utilization coefficient.

[0013] Preferably, the predetermined tunneling length in step S3 is 4.0-5.0 meters.

[0014] The beneficial effects of this invention are as follows: By integrating a self-propelled invert arch trestle with a track-constrained deep-buried drainage ditch milling system, the precision and efficiency challenges in the construction of central drainage ditches in high-altitude and cold-climate tunnels are fundamentally solved. Firstly, the rigid guidance and constraint of the track on the milling machine's trajectory ensures that the drainage ditch is always precisely positioned on the center line of the tunnel invert arch, with a straight line and consistent width and depth. This completely eliminates the positional deviation and line curvature problems inherent in traditional excavator construction, thus guaranteeing uniform thickness of the encasing concrete and graded crushed stone filter layer and reliable drainage function. Secondly, an adaptive speed control algorithm based on surrounding rock strength, milling depth (H), and contact area (S) is introduced, combined with hydraulic system parameter linkage and high-altitude environment operation techniques, to achieve intelligent matching of cutting parameters and geological conditions. This significantly improves milling efficiency while effectively reducing tool wear and equipment overload risks. Thirdly, construction efficiency allows for accurate project forecasting, equipment selection, and performance management. Furthermore, standardized processes (installation of prefabricated components, backfilling of concrete and filter layer) significantly reduce manual intervention and material waste. In summary, this invention combines the advantages of high precision, high efficiency, high reliability, and low cost, and is especially suitable for harsh construction environments such as high-altitude and cold regions, demonstrating significant technological advancement and promotional value. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 for Figure 1 Enlarged view of point A in the middle; Figure 3 for Figure 1 Enlarged view of point B in the middle; Figure 4 This is a schematic diagram of the limiting device structure of the present invention; Figure 5 This is a schematic diagram of the reinforcing iron plate structure of the present invention; Figure 6 This is a side view of the milling system of the present invention.

[0016] Explanation of reference numerals in the attached drawings: 1. Self-propelled arch bridge; 11. Track; 2. Milling system; 21. Traveling trolley; 211. Moving frame; 212. Traveling wheel; 22. Milling machine; 3. Rigid connection mechanism; 31. Channel steel; 32. Crossbar; 4. Protective baffle; 5. Drive motor; 6. Limiting device; 61. High-strength bolt; 62. Reinforcing iron plate. Detailed Implementation

[0017] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and design various embodiments with various modifications suitable for a particular purpose.

[0018] like Figure 1-6 As shown, this invention provides a milling tool for constructing deep-buried central drainage ditches in high-altitude and cold-climate tunnels. The tool includes a self-propelled inverted arch trestle 1 and a deep-buried drainage ditch milling system 2. The self-propelled inverted arch trestle 1 is equipped with a track 11 to guide a traveling trolley 21 along a predetermined path. The deep-buried drainage ditch milling system 2 includes a traveling trolley 21 and a milling machine 22. The traveling trolley 21 has a length of 1800-2200mm (preferably 2000mm) and a width of 500-700mm (preferably 600mm), with a compact overall structure to meet the limited space requirements within the tunnel. The maximum travel distance is L, which is 12000-15000mm (preferably 15000mm), sufficient to meet the construction length requirements for a single inverted arch lining. The traveling trolley 21 is movably mounted on the track 11 and is driven by a drive device to move along the track 11. The traveling trolley 21 includes a movable frame 211 and traveling wheels 212 mounted on the movable frame 211. The traveling wheels 212 cooperate with the track 11. The drive device includes a drive motor 5, which is connected to the traveling wheels 212 for transmission, so as to realize the automatic movement of the traveling trolley 21 along the track 11.

[0019] The milling machine 22 is mounted below the traveling trolley 21 via a rigid connection mechanism 3. The rigid connection mechanism 3 includes two channel steels 31 and a crossbar 32. The two channel steels 31 are welded and fixed to the moving frame 211. The crossbar 32 penetrates the body of the milling machine 22, and both ends of the crossbar 32 are connected to the channel steels 31. The connection between the ends of the crossbar 32 and the channel steels 31 is achieved through a heat-fitting process to achieve an interference fit. Specifically, during assembly, the channel steels 31 with the mounting holes are first locally heated, causing the mounting holes to expand and increase in diameter. Simultaneously, the ends of the crossbar 32 are cooled at low temperature, causing their shaft diameter to shrink. Then, the cooled ends of the crossbar 32 are quickly and accurately aligned and inserted into the heated and expanded mounting holes of the channel steels 31. After the components return to ambient temperature, the diameter of the channel steels 31 shrinks, and the shaft diameter of the crossbar 32 expands, generating a large clamping force at the contact surface, thereby achieving a firm and highly coaxial interference fit connection between the two. To further enhance the fixing effect, the milling machine 22 is also equipped with limiting devices 6 at both ends of its body to restrict its lateral displacement. The limiting device 6 includes high-strength bolts 61 and two reinforcing iron plates 62, each 100mm wide and 50mm thick. Mounting holes are provided on the crossbar 32, through which the high-strength bolts 61 pass and through the reinforcing iron plates 62. The two reinforcing iron plates 62 are detachably connected and locked together with bolts and nuts, effectively preventing lateral displacement or swaying of the milling machine during construction and ensuring construction stability.

[0020] The milling machine 22 employs a hydraulic drive system, including a hydraulic pump station, a hydraulic motor, and a control valve assembly. The hydraulic pump station provides the power source, driving the hydraulic motor through hydraulic pipelines to propel the breaker track for milling operations. This hydraulic system features excellent power density and adaptability, enabling stable operation in high-altitude, low-oxygen, and low-temperature environments, ensuring milling efficiency and reliability. The breaker track of the milling machine 22 uses synthetic diamond saw blades, offering excellent wear resistance and crushing efficiency. The breaker track has a length of 3500-3800mm (preferably 3630mm) and a width of 2000-2500mm (preferably 2300mm), suitable for the cross-sectional dimensions required for deeply buried trenches. A protective baffle 4, preventing flying debris, is welded to the lower part of the traveling trolley 21, located on the side of the milling machine 22. The protective baffle 4 is made of steel plate with a thickness of 8-12mm (preferably 10mm), with a length of 1400-1600mm (preferably 1500mm) and a width of 1500-1700mm (preferably 1600mm). It is used to prevent the flying of gravel during milling, protect the safety of equipment and construction personnel, reduce dust, and improve the working environment.

[0021] The construction method of the milling tool for deep-buried central drainage ditch in high-altitude and cold-climate tunnels of the present invention includes the following steps: S1: Excavate and shape the arch curvature to form the working surface required for ditch construction; S2: Determine the operating speed and efficiency of the milling machine 22, start the drive motor 5, drive the traveling trolley 21, and move the milling machine 22 along the track 11 of the self-propelled invert arch trestle 1 from the closed end of the upper support towards the tunnel face to perform milling and excavation of the deep-buried central drainage ditch. The travel trajectory of the milling machine 22 is constrained by the track 11 to ensure that the milled drainage ditch is located on the center line of the tunnel invert arch and is straight. In this step, a control strategy for the operating speed A and the construction efficiency Q is introduced: The operating speed A of the milling machine 22 is based on the formula: A=a-5×[(H-0.5) / 0.5]-5×[(S-1) / 1]=a-5×[(H-0.5) / 0.5+(S-1)]=a-5×[H / 0.5+S-2)]; The construction rotation speed A is set or dynamically adjusted based on H, S, and a. Here, A is the construction rotation speed (r / min), a is the theoretical rotation speed selected based on the surrounding rock strength (soft rock: 75-80 r / min; medium-hard rock: 50-60 r / min; hard rock: 30-40 r / min), H is the milling depth (m), and S is the contact area between the milling head and the surrounding rock (m²). This achieves adaptive matching of cutting parameters and geological conditions, maximizing tool protection while ensuring efficiency. Simultaneously, the construction efficiency Q of the milling machine 22 is calculated using the formula Q=D×W×V×60×η, used to guide construction progress management. Here, Q is the efficiency (m³ / h), D is the cutting depth (m), W is the cutting width (m), V is the advance speed (m / min), and η is the time utilization coefficient.

[0022] S3: The milling machine 22 stops excavating after excavating a predetermined length, which is 4.0-5.0 meters (preferably 4.5 meters), matching the length of the precast water pipe, and reserving space for joint installation; S4: After the excavation is completed, install the prefabricated trench base and adjust its slope; S5: Install prefabricated water pipes on the ditch base with the adjusted slope; S6: Backfill the middle section with C25 concrete to the design elevation; S7: After the C25 concrete in the middle has set and reached its strength, backfill the top of the precast water pipe with graded crushed stone, and cover the top of the graded crushed stone with geotextile to prevent the initial support concrete from entering the crushed stone layer and causing it to harden, thus affecting the drainage function. S8: Install the initial support steel frame for the invert arch and spray initial support concrete; S9: Repeat steps S2 to S8 until the construction length of the initial support section of the invert arch reaches the length of one invert arch lining plate (12 meters / plate). S10: The mobile self-propelled arch bridge 1 will proceed with the construction of the next arch section.

[0023] In step S2, the control strategies for the introduced construction speed A and construction efficiency Q of the milling machine 22 are as follows: 1. Adaptive setting of construction speed: The construction speed A (unit: r / min) of the milling machine 22 is set or dynamically adjusted according to the formula: A = a - 5 × [(H - 0.5) / 0.5] - 5 × [(S - 1) / 1] = a - 5 × [(H - 0.5) / 0.5 + (S - 1)] = a - 5 × [H / 0.5 + S - 2). A represents the construction speed (r / min), which is the optimal speed per minute for the milling machine.

[0024] 'a' represents the theoretical rotational speed selected based on the strength of the surrounding rock. The principle for its selection is as follows: for soft rock / soil with a compressive strength <15MPa, use 75-80 r / min to improve cutting efficiency; for medium-hard rock with a compressive strength of 20-30MPa, reduce the speed to 50-60 r / min to avoid tool overload and wear; for hard rock with a compressive strength >30MPa, use a low-speed, high-torque mode of 30-40 r / min, and adjust the hydraulic system pressure accordingly.

[0025] H represents the milling depth (unit: m), which refers to the depth to which the milling head cuts into the material in one go (in the direction perpendicular to the working face).

[0026] S is the contact area between the milling head and the surrounding rock (unit: m²).

[0027] 5 × [(H-0.5) / 0.5] represents the milling head cutting into the material to a depth exceeding 0.5 meters in a single pass; for every additional 0.5 meters, the rotation speed decreases by 5 revolutions per minute. 5 × [(S-1) / 1] represents the milling head working face contacting the surrounding rock to a contact area exceeding 1 square meter; for every additional 1 square meter, the rotation speed decreases by 5 revolutions per minute. This achieves adaptive matching of cutting parameters to geological conditions, maximizing tool protection while ensuring efficiency.

[0028] 2. Techniques for adjusting the speed of a milling machine: Tool coordination: Cutting tools of the blade type are used for high-speed cutting of soft rock, while pick-type cutting tools are used and the rotational speed is reduced when splitting and fracturing medium-hard rock. Simultaneously, the wear condition of the cutting tools is checked regularly, and the rotational speed is reduced or the tools are replaced when wear is severe. Hydraulic system linkage: Maintaining a stable hydraulic system flow rate of 220 L / min and a rotational speed of 78 r / min ensures optimal power output. Under high-pressure conditions such as system pressure rising to 35 MPa, the rotational speed should be actively reduced to prevent overload of the hydraulic motor. High-altitude environment operation: For high-altitude and cold environments, after a cold start, run at 50% of the rated speed for preheating. Once the hydraulic oil temperature reaches 40℃, gradually increase the speed to the operating speed. The PLC system monitors cutting resistance in real time and automatically adjusts the speed and feed rate. Every 500 hours of operation, check the spindle bearing clearance to ensure speed stability.

[0029] Estimation and management of milling machine construction efficiency: Construction efficiency Q (unit: m³ / h) can be estimated in advance using the formula Q=D×W×V×60×η, which is used to guide construction progress management. Where: Q represents efficiency (m³ / h), which is the effective volume of material actually removed per hour.

[0030] D is the cutting depth (m), the depth to which the milling head cuts into the material in one go (in the direction perpendicular to the working surface).

[0031] W represents the cutting width (m), which is the effective working width of the milling head (the transverse width along the working surface).

[0032] V represents the propulsion speed (m / min), which is the average speed at which the milling machine moves forward along the working surface during operation.

[0033] 60 is the unit conversion factor to convert minutes (min) to hours (h), because speed V is usually measured in minutes.

[0034] η is the time utilization coefficient / overall efficiency coefficient, an empirical value between 0.4 and 0.8, used to comprehensively consider the efficiency reduction caused by all non-pure cutting time, such as tool changing, shifting, equipment maintenance, personnel rest, and geological condition fluctuations.

[0035] (D×W)×V: Represents the theoretical volume of material milled per minute (m³ / min).

[0036] (D×W×V)×60: Represents the theoretical volume of material milled per hour (m³ / h), assuming the machine is cutting at high efficiency.

[0037] (D×W×V×60)×η: Multiply the theoretical volume by a coefficient η less than 1 to obtain the effective excavation volume (Q) per hour, which is closer to the actual engineering situation.

[0038] Efficiency Improvement Approaches and Applications: Based on the above formula, the ways to improve efficiency are: maximizing the cutting depth (D) and width (W) within the equipment's capacity; optimizing the feed speed (V) while ensuring the equipment is not overloaded and tool wear is acceptable; and improving the time utilization coefficient (η) through refined management, skilled operation, and reducing non-operational time. In practical applications, this efficiency calculation formula can be used for: Estimate the workload: Based on the geological report, make a preliminary estimate of Q and formulate a scientific construction plan.

[0039] Equipment selection: Select a milling machine with matching power and size based on the required Q value.

[0040] Performance appraisal: Compare actual Q with theoretical values ​​to measure operational level and management efficiency.

[0041] Parameter optimization: Experiment with different D and V parameters in the field to find the most efficient combination.

[0042] This invention constrains the milling machine's trajectory via a track, ensuring the drainage ditch remains aligned with the tunnel invert centerline, maintaining a straight line and consistent width and depth. This avoids the positional deviations and linear curvature issues common in traditional excavator construction, guaranteeing uniform filter layer thickness and reliable drainage. The use of prefabricated ditch bases and water pipe installation, combined with graded crushed stone and geotextile covering layers, effectively prevents concrete slab compaction and ensures drainage. The standardized and mechanized construction process significantly improves efficiency, reduces manual intervention, and lowers material waste and construction costs. It is particularly suitable for harsh construction environments such as high-altitude and frigid zones, demonstrating high potential for widespread application.

Claims

1. A milling tool for deep-buried central drainage ditches in high-altitude and cold-climate tunnels, characterized in that: The utility model relates to a self-propelled inverted arch trestle (1) and a deep buried ditch milling and digging system (2), the self-propelled inverted arch trestle (1) is provided with a track (11), the deep buried ditch milling and digging system (2) includes a travelling trolley (21) and a milling and digging machine (22), the travelling trolley (21) is movably arranged on the track (11) and drives the travelling trolley (21) to walk along the track (11) by a driving device, the milling and digging machine (22) is installed below the travelling trolley (21) through a rigid connecting mechanism (3), the lower part of the travelling trolley (21) is welded with a protective baffle (4) for preventing gravel splashing, and the protective baffle (4) is located at the side of the milling and digging machine (22).

2. The high-altitude alpine tunnel deep-buried center ditch milling and digging tool according to claim 1, characterized in that: The travelling trolley (21) includes a moving frame (211) and a walking wheel (212) arranged on the moving frame (211), the walking wheel (212) is matched with the track (11), and the driving device includes a driving motor (5) in transmission connection with the walking wheel (212).

3. The high-altitude alpine tunnel deep-buried center ditch milling and digging tool according to claim 2, characterized in that: The rigid connecting mechanism (3) includes two channel steels (31) and a cross bar (32), the two channel steels (31) are fixedly arranged on the moving frame (211), the cross bar (32) penetrates the body of the milling and digging machine (22), the two ends of the cross bar (32) are connected with the channel steels (31) respectively, and the body of the milling and digging machine (22) is further provided with a limiting device (6) for limiting the transverse displacement.

4. The high-altitude alpine tunnel deep-buried center ditch milling and digging tool according to claim 3, characterized in that: The limiting device (6) includes high-strength bolts (61) and two reinforced iron plates (62), the cross bar (32) is provided with mounting holes, the high-strength bolts (61) pass through the mounting holes and the reinforced iron plates (62), and the two reinforced iron plates (62) are detachably connected.

5. The high-altitude alpine tunnel deep-buried center ditch milling and digging tool according to claim 1, characterized in that: The crushing caterpillar belt of the milling and digging machine (22) adopts a synthetic diamond saw blade, the length of the crushing caterpillar belt is 3500-3800mm, and the width is 2000-2500mm.

6. The high-altitude alpine tunnel deep-buried center ditch milling and digging tool according to claim 1, characterized in that: The length of the travelling trolley (21) is 1800-2200mm, the width is 500-700mm, and the maximum walking stroke is 12000-15000mm.

7. The high-altitude alpine tunnel deep-buried center ditch milling and digging tool according to claim 1, characterized in that: The protective baffle (4) is made of a steel plate with a thickness of 8-12mm, the length is 1400-1600mm, and the width is 1500-1700mm.

8. A construction method of a high-altitude alpine tunnel deep-buried center ditch milling and digging tool, characterized in that: The utility model relates to a self-propelled inverted arch trestle (1) and a deep buried ditch milling and digging system (2), the self-propelled inverted arch trestle (1) is provided with a track (11), the deep buried ditch milling and digging system (2) includes a travelling trolley (21) and a milling and digging machine (22), the travelling trolley (21) is movably arranged on the track (11) and drives the travelling trolley (21) to walk along the track (11) by a driving device, the milling and digging machine (22) is installed below the travelling trolley (21) through a rigid connecting mechanism (3), the lower part of the travelling trolley (21) is welded with a protective baffle (4) for preventing gravel splashing, and the protective baffle (4) is located at the side of the milling and digging machine (22). The utility model relates to a self-propelled inverted arch trestle (1) and a deep buried ditch milling and digging system (2), the self-propelled inverted arch trestle (1) is provided with a track (11), the deep buried ditch milling and digging system (2) includes a travelling trolley (21) and a milling and digging machine (22), the travelling trolley (21) is movably arranged on the track (11) and drives the travelling trolley (21) to walk along the track (11) by a driving device, the milling and digging machine (22) is installed below the travelling trolley (21) through a rigid connecting mechanism (3), the lower part of the travelling trolley (21) is welded with a protective baffle (4) for preventing gravel splashing, and the protective baffle (4) is located at the side of the milling and digging machine (22). The utility model relates to a self-propelled inverted arch trestle (1) and a deep buried ditch milling and digging system (2), the self-propelled inverted arch trestle (1) is provided with a track (11), the deep buried ditch milling and digging system (2) includes a travelling trolley (21) and a milling and digging machine (22), the travelling trolley (21) is movably arranged on the track (11) and drives the travelling trolley (21) to walk along the track (11) by a driving device, the milling and digging machine (22) is installed below the travelling trolley (21) through a rigid connecting mechanism (3), the lower part of the travelling trolley (21) is welded with a protective baffle (4) for preventing gravel splashing, and the protective baffle (4) is located at the side of the milling and digging machine (22). ​ ​ ​ ​ S7: After the middle part C25 concrete is coagulated and reaches the strength, backfill the prefabricated water pipe top graded gravel, and cover the top of the graded gravel with geotextile to prevent the primary support concrete from entering the gravel layer and causing its compaction and affecting the drainage function; S8: Install the inverted arch primary support steel frame and spray the primary support concrete; S9: Repeat steps S2 to S8 until the inverted arch primary support section construction length reaches the length of the inverted arch lining of one slab; S10: Move the self-propelled inverted arch trestle (1) to conduct the construction of the next slab inverted arch section.

9. The construction method of the high-altitude alpine tunnel deep-buried center ditch milling and digging tooling according to claim 8, characterized in that: In step S2, the construction rotating speed A of the milling and digging machine (22) is set or dynamically adjusted according to the formula A=a-5×[(H-0.5) / 0.5]-5×[(S-1) / 1]=a-5×[(H-0.5) / 0.5+(S-1)]=a-5×[H / 0.5+S-2)]. Wherein, A is the construction rotating speed (r / min), a is the theoretical rotating speed selected according to the strength of the surrounding rock, H is the milling and digging depth (m), and S is the contact area of the milling and digging head with the surrounding rock (m²); The construction efficiency Q of the milling and digging machine (22) is calculated according to the formula Q=D×W×V×60×η. Wherein, Q is the efficiency (m³ / h), which refers to the effective volume of the actual excavated material per hour, D is the cutting depth (m), W is the cutting width (m), V is the advancing speed (m / min), and η is the time utilization coefficient.

10. The construction method of the high-altitude alpine tunnel deep-buried center ditch milling and digging tooling according to claim 8, characterized in that: The predetermined tunneling length in step S3 is 4.0-5.0 meters.

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