Tunneling roadway turning construction method and roadway construction method

Abstract

The invention discloses an excavation roadway turning construction method and a roadway construction method. According to the method, the turning track is accurately controlled through geological parameter pre-research and surveying and setting-out, and the problems of relaxation and damage caused by track deviation and long surrounding rock exposure time of a traditional turning section are effectively solved in combination with pilot tunnel advanced excavation and dynamic collaborative supporting. Pilot tunnel advanced excavation reserves a space for subsequent expanded excavation, a cutting head of the integrated equipment can horizontally rotate to adapt to curve excavation, and supporting force is dynamically adjusted in cooperation with real-time scanning of surrounding rock deformation data, so that the surrounding rock exposure time in turning section construction is shortened to 5-8 minutes from 40-60 minutes of a traditional process, and the construction efficiency is improved. The wall caving and roof caving risks caused by long-time support-free exposure of the surrounding rock in the turning area are remarkably reduced, meanwhile, it is ensured that the turning radius and the turning angle are matched with the design height through a parameter correction program, and the accuracy and safety of turning section construction are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of tunnel turning construction, and in particular relates to a tunneling tunnel turning construction method and a tunnel construction method. Background Art

[0002] Tunnel turning construction refers to the process of creating curved sections between straight tunnel sections in mines, tunnels, or underground projects, in accordance with design requirements, to meet requirements for tunnel layout, avoid geological structures, connect different working faces, or optimize ventilation and transportation systems. Turning construction requires the rational determination of turning radius, curvature, and cross-sectional parameters, while ensuring surrounding rock stability and reliable support. Appropriate tunneling equipment and processes, such as drilling and blasting, tunnel boring machines, or combined tunneling, must be employed. During construction, enhanced geological advance surveys are necessary to control blasting vibrations and surrounding rock deformation to ensure tunnel quality and construction safety. Furthermore, strengthened support measures, such as anchor mesh spraying, U-shaped steel arches, or concrete arches, are often required in turning sections to improve structural stability. Scientific and rational turning construction is crucial for ensuring the safe and efficient progress of underground projects.

[0003] However, existing technologies generally have problems in tunnel turning construction, such as insufficient trajectory control accuracy, separation of cutting and support processes, which leads to long-term exposure of surrounding rock and easy relaxation and damage, fixed support parameters that are prone to insufficiency or redundancy, inconsistent process connection affecting efficiency, and lack of a full-cycle monitoring and feedback mechanism that makes it difficult to dynamically optimize the design. These problems make it difficult to strike a balance between construction safety, efficiency and long-term reliability. Summary of the Invention

[0004] The purpose of the present invention is to provide a tunnel turning construction method and a tunnel construction method in order to solve the above-mentioned problems.

[0005] The technical solution adopted by the present invention is as follows: a tunnel turning construction method and a tunnel construction method, the method comprising the following steps:

[0006] S1: Obtain the surrounding rock mechanical parameters and groundwater distribution data of the turning section of the roadway through 3D seismic exploration and core drilling. Combined with the design requirements, the turning radius, turning angle, and slope change point coordinates are determined. The results are input into S2 as the basic parameters for trajectory planning.

[0007] S2: Using a total station-laser tracker combined system, measurement benchmarks are arranged at the starting point, slope change point, and end point of the tunnel based on the S1 parameters. A laser scanner is used to scan the excavated section every 5 meters of excavation, and the deviation value is compared with the designed trajectory. The deviation data is fed back to S1 to correct the preliminary research parameters.

[0008] S3: In the starting position of the turning section, a small-section pilot tunnel is excavated in advance, and the profile of the pilot tunnel is expanded by 200 mm outside the designed trajectory; after excavation, temporary support is immediately applied, and the support strength is adjusted according to the S1 surrounding rock parameters to provide a safe space for the S4 main section construction;

[0009] S4: Integrated tunneling equipment is used, the front cantilever tunneling machine cutting head can rotate ±45° to adapt to the turning, and the rear side is equipped with a telescopic hydraulic support frame; when the tunneling machine is cutting, the support frame follows synchronously, and the support force is automatically adjusted according to the real-time scanning of the surrounding rock deformation data of S2, realizing synchronous operation of "cutting-supporting", avoiding the risk of exposure of the surrounding rock between the temporary support of S3 and the subsequent permanent support;

[0010] S5: Based on the S3 pilot tunnel, the section is expanded to the designed size by smooth blasting; the blasting parameters are adjusted according to the surrounding rock strength of S1, and the newly exposed section after blasting is covered by the S4 support frame to prevent local spalling caused by expansion from affecting the S6 permanent support construction;

[0011] S6: The permanent support is completed within 24 hours after the expansion of the section in S5: the top adopts combined support of anchor rod + W-shaped steel belt + anchor cable, and the side adopts anchor rod; the anchor rod anchoring force and the anchor cable pretightening force are dynamically adjusted according to the surrounding rock pressure data recorded by the S4 support frame, forming a continuous bearing structure with the S3 temporary support and the S4 collaborative support;

[0012] S7: A counter-rotating local fan is arranged at the entrance of the roadway, and the air outlet moves synchronously with the S4 tunneling equipment; the ventilation volume is automatically adjusted according to the gas concentration after S5 blasting, and a wet dust removal fan is started at the same time to ensure that the dust concentration meets the standard during the S4 rock breaking and S6 support operations, ensuring the health of the operating personnel and the operation precision of the equipment;

[0013] S8: Small rubber-tyred vehicles are used to transport gangue during the pilot tunnel excavation stage; after the main section is expanded, a scraper conveyor is switched, and the conveyor head moves forward once every 8 hours as the working face advances, and the curvature radius of the conveyor in the turning section matches the designed turning radius of S1; the transportation efficiency data feedback adjusts the tunneling speed of S4;

[0014] S9: Sensors are arranged on the roof and two sides of the roadway, and data is transmitted in real time to the ground monitoring center through the 5G network; when the surrounding rock displacement rate is monitored to be out of limit, the system automatically sends instructions to the S4 collaborative support equipment and prompts S6 to speed up the permanent support progress, while correcting the S1 pre-research parameters to form a closed-loop optimization.

[0015] In a preferred embodiment, in step S1, before construction, the turning section of the tunnel is covered and scanned by a three-dimensional seismic exploration system, and the drilling and coring operation is carried out. The drilling spacing is controlled at 5 meters to obtain mechanical parameters such as the compressive strength of the surrounding rock, the density of joint development, and the elastic modulus, and the groundwater infiltration rate and distribution range are recorded simultaneously; based on the requirements of the design drawings and combined with the exploration data, the turning radius R, the steering angle θ and the three-dimensional coordinates of the slope change point are calculated and determined. The turning radius value is determined according to the tunnel cross-sectional dimensions of 4.5 meters wide and 3.8 meters high and the passability of the tunneling equipment. The minimum R is ≥ 15 meters, and the steering angle error is controlled within ±0.5°.

[0016] In a preferred embodiment, in step S2, a high-precision total station and laser tracker combined measurement system is used to bury permanent metal reference points at the starting point, slope change point and end point of the tunnel, with a diameter of 20 mm and a burial depth of 500 mm. The coordinate error of the reference points is controlled within ±2 mm. During the excavation process, the laser scanner is started every 5 meters to perform point cloud scanning on the excavated section, and the measured point cloud data is aligned with the design trajectory point cloud pre-researched in S1 to extract the section contour deviation value, and the horizontal and vertical deviations are controlled within ±50 mm.

[0017] In a preferred embodiment, in step S3, a small-section pilot tunnel is used for advance excavation at the starting position of the turning section. The pilot tunnel has a specification of 2.5 meters in width and 2.8 meters in height, and its contour line is expanded by 200 mm according to the designed turning trajectory to reserve space for the expansion of the main section; temporary support is immediately applied after the excavation of the pilot tunnel: Φ20 mm mortar anchor rods with a length of 2.2 meters are used, arranged at a spacing of 1000 mm × 1000 mm, and the exposed length of the anchor rods is controlled at 150 mm; the anchor rods are hung with a 6 mm diameter steel mesh with a grid of 200 mm × 200 mm, and then C20 concrete is sprayed with a thickness of 100 mm; if the S1 preliminary study shows that the density of surrounding rock joint development exceeds 3 / square meter, the anchor rod spacing is increased to 800 mm × 800 mm, and the thickness of the sprayed concrete is increased to 120 mm; after the temporary support is completed, a stable working space is provided for the construction of the S4 main section, with a clearance height ≥2.5 meters and a width ≥2.2 meters.

[0018] In a preferred embodiment, in step S4, a laser scanner is used to perform point cloud scanning on the excavated section every 5 m, and the measured point cloud is registered with the theoretical point cloud of the designed trajectory to extract the absolute displacement and deformation rate of each monitoring point on the surrounding rock surface;

[0019] When the laser scanner detects that the deformation rate v of the surrounding rock in a certain area exceeds the reference value v0, the control module calls the correlation law of "deformation rate-support force" under similar surrounding rock conditions in the historical database, and combines it with the real-time load status of the current hydraulic support frame to calculate the support force increment ΔF that needs to be adjusted; if the deformation rate is lower than v0, the support force is appropriately reduced to reduce equipment energy consumption;

[0020] The dynamic matching formula of “deformation rate-support force” is:

[0021]

[0022] in:

[0023] F represents the real-time support force that needs to be applied currently;

[0024] F0 represents the initial set reference support force;

[0025] k represents the sensitivity coefficient of surrounding rock;

[0026] v represents the deformation rate of the surrounding rock monitored in real time by the laser scanner;

[0027] v0 represents the design safety basis deformation rate.

[0028] In a preferred embodiment, in step S5, the cross section is expanded to the design specification of 4.5 meters wide and 3.8 meters high by using a smooth blasting process with S3 pilot tunnel as the center; the blasting hole arrangement is divided into three categories: slot holes, auxiliary holes and peripheral holes: the slot holes adopt wedge-shaped slots, with a hole depth of 2.5 meters, a hole diameter of 42 mm, a hole spacing of 400 mm, and a charge of 2.5 kg per hole; the auxiliary holes are arranged along the periphery of the slot holes, with a hole depth of 2.4 meters, a hole diameter of 42 mm, a hole spacing of 600 mm, and a charge of 2 kg per hole; the peripheral holes are close to the design contour line, with a hole depth of 2.3 meters, a hole diameter of 42 mm, a hole spacing of 350 mm, and an interval charging structure; the blasting parameters are based on According to the S1 preliminary study, the surrounding rock strength is dynamically adjusted: if the compressive strength of the surrounding rock is greater than 80 MPa, the spacing between the peripheral holes is expanded to 400 mm, and the charge per hole is increased to 1 kg; if the compressive strength of the surrounding rock is less than 40 MPa, the spacing between the peripheral holes is reduced to 300 mm, and the charge per hole is reduced to 0.6 kg; the detonation sequence is slot hole → auxiliary hole → peripheral hole, and millisecond delay detonators are used to control blasting vibration; the S4 hydraulic support frame is immediately started after blasting, and its retractable support arm covers the newly exposed section. By applying a support force of 800-1000 kN, the surrounding rock surface is constrained to prevent local spalling caused by excavation, providing stable working surface conditions for the S6 permanent support construction.

[0029] In a preferred embodiment, in step S6, permanent support is completed within 24 hours after the main section of S5 is expanded to the design specifications of 4.5 meters in width and 3.8 meters in height; a Φ22 mm left-handed anchor rod without longitudinal reinforcement is used at the top, with a length of 2.8 meters and an arrangement of 800 mm × 800 mm spacing, and a W-shaped steel belt with a thickness of 3 mm and a width of 250 mm is matched at the tail of the anchor rod; at the same time, a Φ17.8 mm steel strand anchor cable is arranged with a length of 6.3 meters and a spacing of 2000 mm × 2000 mm, and the anchor cable preload force is initially set to 200 kN; a Φ20 mm ordinary mortar anchor rod is used at the side, with a length of 2.4 meters and a spacing of 1000 mm × 1000 mm.

[0030] In a preferred embodiment, in step S7, a counter-rotating local ventilator, model FBD No. 6.3 / 2×30, with a rated air volume of 2000 cubic meters per minute, is arranged at the entrance of the tunnel. The air outlet is connected through a flexible wind tube, and the end of the wind tube moves synchronously with the S4 tunneling equipment, with a distance of ≤5 meters from the tunnel face; the ventilation volume is controlled by real-time monitoring data of the gas sensor. When the gas concentration exceeds 0.8% after S5 blasting, the ventilator automatically switches to high-speed mode and the air volume is increased to 2500 cubic meters per minute; when the gas concentration is lower than 0.5%, it returns to the rated air volume; at the same time, the wet dust removal fan is started, with a processing air volume of 1500 cubic meters per minute and a dust removal efficiency of 95%. Through the spray dust suppression device, the water pressure is 8 MPa, and the droplet size is ≤50 microns, the dust concentration of the working surface is controlled below 10 mg / cubic meter, ensuring the respiratory safety of S4 rock breaking and S6 support workers and the accuracy of equipment sensors.

[0031] In a preferred embodiment, in step S8, a small rubber-wheeled transport vehicle with a load capacity of 5 tons and a wheelbase of 2.2 meters is used in the pilot tunnel excavation stage, i.e., the S3 stage, which is suitable for small-section transportation. The waste rock transportation is completed once every 20 minutes, and the single transportation volume is 4 tons. After the main section is expanded, i.e., the S5 stage, it is switched to a scraper conveyor, model SGZ630 / 160, with a transportation capacity of 500 tons / hour. The conveyor head moves forward once every 8 hours as the face advances, with a forward movement distance of 3 meters. The curvature radius of the conveyor in the turning section is controlled within ±200 mm from the S1 design turning radius R. The transportation system collects single-shift transportation volume data in real time. The normal operating condition is 800-1000 tons / shift. If the transportation volume is lower than 700 tons / shift, the S4 roadheader automatically reduces the cutting speed by 10%, and the cutting head speed is reduced from 45 rpm to 40 rpm.

[0032] In a preferred embodiment, in step S9, a fiber Bragg grating displacement sensor is arranged on the tunnel roof with a range of ±50 mm and an accuracy of 0.01 mm, and anchor axial force sensors are arranged on both sides with a range of 0-500 kN and an accuracy of 1 kN. At the same time, a gas sensor is installed 10 meters away from the tunnel face with a range of 0-4% and an accuracy of 0.01%.

[0033] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0034] 1. This invention uses preliminary geological parameter research and surveying to precisely control the turning trajectory, combined with pilot tunnel excavation and dynamic collaborative support, to effectively address the loosening and damage problems in traditional turning sections caused by trajectory deviation and long exposure time of surrounding rock. Pilot tunnel excavation reserves space for subsequent excavation expansion. The integrated equipment's cutting head can rotate horizontally to adapt to curved excavation, and dynamically adjusts support force based on real-time scanning of surrounding rock deformation data. This reduces the exposure time of surrounding rock during turning section construction from 40-60 minutes in traditional processes to 5-8 minutes, significantly reducing the risk of spalling and roof collapse caused by prolonged unsupported exposure of surrounding rock in the turning area. A parameter correction program also ensures that the turning radius and steering angle are highly consistent with the design, improving the accuracy and safety of turning section construction.

[0035] 2. In the present invention, an intelligent collaborative mode of pre-research-measurement-support-rock breaking-monitoring is adopted. The operation mode of simultaneous advancement of cutting and support breaks the time interval between traditional processes, realizes continuous operation from pilot tunnel excavation to permanent support, and greatly improves construction efficiency. The mechanism of real-time monitoring of surrounding rock deformation and dynamic adjustment of support force enables the support strength to be accurately matched with the stress state of the surrounding rock, avoids the waste of resources or insufficient support caused by "one-size-fits-all" support, and enhances the overall stability of the surrounding rock. The intelligent ventilation and dust removal system ensures the safety of the working environment, the dynamic optimization of the transportation route avoids the blockage of waste rock accumulation, and the full-cycle monitoring feedback forms a closed-loop optimization of "design-construction-correction", which fundamentally improves the long-term service reliability of the tunnel and realizes a comprehensive improvement in construction safety, efficiency and economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the process principle of the present invention. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0038] Example:

[0039] Reference Figure 1 A tunnel turning construction method and a tunnel construction method, the method comprising the following steps

[0040] S1: Obtain the mechanical parameters of the surrounding rock and the distribution data of underground water in the turning section of the roadway through three-dimensional seismic exploration and drilling core sampling, and determine the turning radius, turning angle and coordinate of the slope change point according to the design requirements. The results are input into S2 as the basic parameters for trajectory planning.

[0041] S2: Use a total station-laser tracker combined system to arrange measurement reference points at the starting point, slope change point and end point of the roadway based on the parameters in S1; scan the excavated section every 5m through a laser scanner, compare the deviation value (controlled within ±50mm) with the designed trajectory, and feed back the deviation data to S1 to correct the pre-research parameters.

[0042] S3: Excavate a small cross-section pilot adit (2.5m wide x 2.8m high) in advance at the starting position of the turning section, and expand the profile of the pilot adit by 200mm outward according to the designed trajectory; immediately after excavation, install temporary support (anchor rod + mesh jet concrete) with support strength adjusted according to the surrounding rock parameters in S1 to provide a safe space for S4 main section construction.

[0043] S4: Dynamic coordinated rock breaking-support operation (inventive step)

[0044] Use integrated tunneling equipment, the cutting head of the front cantilever tunneling machine can rotate ±45° to adapt to the turning, and the rear side is equipped with a telescopic hydraulic support frame (covering the 3m section behind the tunneling machine); when the tunneling machine is cutting, the support frame follows synchronously, automatically adjusts the support force according to the real-time scanning of the surrounding rock deformation data in S2, realizes synchronous operation of "cutting-support", and avoids the risk of exposure of the surrounding rock between the temporary support in S3 and the subsequent permanent support.

[0045] S5: Use smooth blasting to expand the section to the designed size (4.5m wide x 3.8m high) with the S3 pilot adit as the center; adjust the blasting parameters according to the surrounding rock strength in S1; after blasting, cover the newly exposed section with the support frame in S4 to prevent local spalling caused by expansion from affecting the S6 permanent support construction.

[0046] S6: Complete the permanent support within 24 hours after the expansion of the section in S5: use anchor rod + W-shaped steel belt + anchor cable combined support for the top, and anchor rod for the side; dynamically adjust the anchor rod anchoring force and anchor cable pretightening force according to the surrounding rock pressure data recorded by the support frame in S4, and form a continuous load-bearing structure with the S3 temporary support and S4 collaborative support.

[0047] S7: Arrange counter-rotating local ventilators at the entrance of the roadway, and move the air outlet synchronously with the S4 tunneling equipment (distance from the working face ≤5m); automatically adjust the ventilation volume according to the gas concentration after S5 blasting, and start the wet dust removal fan at the same time to ensure that the dust concentration meets the standard during the S4 rock breaking and S6 support operations, and to protect the health of the workers and the operation accuracy of the equipment.

[0048] S8: During the pilot tunnel excavation phase (S3), small rubber-wheeled vehicles are used to transport waste rock. After the main section is expanded (S5), a scraper conveyor is used, and the conveyor head moves forward once every 8 hours as the tunnel face advances. The curvature radius of the conveyor in the turning section matches the turning radius designed in S1. Transport efficiency data is fed back to S4 to adjust the excavation speed to avoid waste rock accumulation affecting subsequent processes.

[0049] S9: Sensors are arranged on the top and sides of the tunnel (to monitor surrounding rock displacement, anchor axial force and gas concentration), and data is transmitted to the ground monitoring center in real time through the 5G network; when the surrounding rock displacement rate is detected to be out of limit (warning value 5mm / d), the system automatically sends instructions to the S4 collaborative support equipment (increase support force by 20%) and prompts S6 to speed up the permanent support progress, while correcting the S1 pre-research parameters to form a "design-construction-monitoring" closed-loop optimization.

[0050] In the step S1, before construction, the turning section of the tunnel is covered and scanned by a three-dimensional seismic exploration system, and the drilling and coring operation is carried out. The drilling spacing is controlled at 5 meters to obtain mechanical parameters such as the compressive strength of the surrounding rock, the density of joint development, and the elastic modulus, and the groundwater infiltration rate and distribution range are recorded simultaneously. Based on the requirements of the design drawings, the turning radius R, the steering angle θ and the three-dimensional coordinates of the slope change point are calculated and determined in combination with the exploration data. The turning radius value is determined according to the tunnel section size of 4.5 meters wide and 3.8 meters high and the passability of the tunneling equipment. The minimum R is ≥ 15 meters, and the steering angle error is controlled within ± 0.5°. All pre-research data are formed into electronic documents and transmitted in real time to the total station system of the S2 measurement and layout link as the basic parameters for trajectory planning.

[0051] In step S2, a high-precision total station and laser tracker combined measurement system is used to bury permanent metal reference points at the starting point, slope change point, and end point of the tunnel. The diameter is 20 mm and the burial depth is 500 mm. The coordinate error of the reference points is controlled to ±2 mm. During the excavation process, the laser scanner is activated every 5 meters to scan the point cloud of the excavated section. The measured point cloud data is aligned with the designed trajectory point cloud of the S1 pre-research, and the cross-section profile deviation value is extracted. The horizontal and vertical deviations are both controlled within ±50 mm. The deviation data is fed back to the S1 pre-research system in real time via the 4G network, triggering the parameter correction program. If the deviation exceeds 30 mm for three consecutive times, the turning radius R value is automatically adjusted to ensure that the subsequent excavation trajectory is highly consistent with the design plan.

[0052] In step S3, a small-section pilot tunnel is excavated at the starting point of the turning section. The pilot tunnel specifications are 2.5 meters wide and 2.8 meters high. Its contour is expanded 200 mm according to the designed turning trajectory to reserve space for the main section expansion. Temporary support is immediately implemented after the pilot tunnel is excavated: 20 mm mortar anchors are used, 2.2 meters long, arranged at a spacing of 1000 mm x 1000 mm, and the exposed length of the anchors is controlled to 150 mm. The anchors are hung with a 6 mm diameter steel mesh with a mesh size of 200 mm x 200 mm, and then C20 concrete with a thickness of 100 mm is sprayed. If the S1 preliminary study shows that the density of surrounding rock joints exceeds 3 per square meter, the anchor spacing is increased to 800 mm x 800 mm, and the thickness of the sprayed concrete is increased to 120 mm. After the temporary support is completed, a stable working space is provided for the construction of the S4 main section, with a clearance height of ≥ 2.5 meters and a width of ≥ 2.2 meters.

[0053] In step S4, a laser scanner scans the excavated section every 5 meters using a point cloud. The measured point cloud is then aligned with the theoretical point cloud of the designed trajectory to extract the absolute displacement (e.g., roof subsidence, two-wall convergence) and deformation rate (displacement change per unit time) of each monitoring point on the surrounding rock surface. This data is transmitted in real time via the 5G network to the intelligent control module of the integrated tunneling equipment. The module has a built-in surrounding rock-support interaction model that dynamically calculates the required support force based on the current deformation rate, historical support effects, and the designed safety threshold (e.g., deformation rate ≤ 5mm / d).

[0054] When the laser scanner detects that the deformation rate v of the surrounding rock in a certain area exceeds the baseline value v0, the control module calls the historical database's correlation between "deformation rate-support force" for similar surrounding rock conditions (for example, every 1mm / d increase in hard rock deformation rate requires a 200kN increase in support force). Combined with the current real-time load status of the hydraulic support frame (to avoid equipment overload), it calculates the required support force increment ΔF. If the deformation rate is lower than v0, the support force is appropriately reduced to reduce equipment energy consumption. This process achieves a millisecond-level closed-loop response of "deformation data acquisition-model calculation-support force adjustment," ensuring that when cutting and support operations proceed simultaneously, the surrounding rock exposure time is shortened from 40-60 minutes in traditional processes to 5-8 minutes, significantly reducing the risk of loosening and damage caused by prolonged exposure.

[0055] The dynamic matching formula of “deformation rate-support force” is:

[0056]

[0057] in:

[0058] F represents the real-time support force that needs to be applied currently (unit: kN);

[0059] F0 represents the initially set reference support force (determined based on the surrounding rock strength and tunnel cross-section dimensions from the S1 preliminary study, 1200 kN for hard rock and 800 kN for soft rock);

[0060] k represents the surrounding rock sensitivity coefficient (determined by parameters such as the degree of joint development and groundwater influence obtained in the S1 preliminary study, with k = 0.3k = 0.3 in the joint-dense area and k = 0.15 in the intact rock layer);

[0061] v represents the surrounding rock deformation rate monitored in real time by the laser scanner (unit: mm / d);

[0062] v0 represents the design safety benchmark deformation rate (5mm / d, if it exceeds this value, the support needs to be strengthened).

[0063] The creativity of this formula lies in directly linking the real-time deformation rate with the safety threshold through the dimensionless ratio v / v0, and reflecting the differences in different geological conditions in combination with the surrounding rock sensitivity coefficient k. It not only ensures the timeliness of support force adjustment (based on real-time deformation data), but also takes into account the complexity of geological conditions (through k correction), avoiding the waste of resources or insufficient support caused by the "one-size-fits-all" support force setting in traditional processes.

[0064] In step S5, the cross-section of the tunnel, centered on the S3 pilot tunnel, was expanded to the designed specifications of 4.5 meters wide by 3.8 meters high using smooth blasting. Blasting holes were arranged in three categories: slot holes, auxiliary holes, and peripheral holes. The slot holes used a wedge-shaped cut, with a depth of 2.5 meters, a diameter of 42 mm, and a spacing of 400 mm. Each hole was charged with 2.5 kg of explosives. The auxiliary holes were arranged along the periphery of the slot holes, with a depth of 2.4 meters, a diameter of 42 mm, and a spacing of 600 mm. Each hole was charged with 2 kg of explosives. The peripheral holes, closely following the designed contour, had a depth of 2.3 meters, a diameter of 42 mm, and a spacing of 350 mm. Blasting holes were arranged using a spaced charge structure. Blasting parameters were dynamically adjusted based on the surrounding rock strength determined in the S1 preliminary study. If the surrounding rock compressive strength exceeded 80 MPa, the spacing between the peripheral holes was increased to 400 mm, and the charge per hole was increased to 1 kg. If the surrounding rock compressive strength was less than 40 MPa, the spacing between the peripheral holes was reduced to 300 mm, and the charge per hole was reduced to 0.6 kg. The detonation sequence was slot hole → auxiliary hole → peripheral hole, with millisecond delay detonators used to control blasting vibrations. Immediately after blasting, the S4 hydraulic support frame was activated, its retractable support arms covering the newly exposed section. By applying a support force of 800-1000 kN, it constrained the surrounding rock surface, preventing localized spalling caused by excavation and providing stable working conditions for the S6 permanent support construction.

[0065] In step S6, permanent support is completed within 24 hours after the main section of S5 is expanded to the designed specifications of 4.5 meters wide by 3.8 meters high. 22mm Φ left-handed unreinforced anchor rods are used at the top, 2.8 meters long and arranged at 800mm x 800mm spacing. W-shaped steel strips with a thickness of 3mm and a width of 250mm are used at the tail of the anchor rods. Simultaneously, 17.8mm Φ stranded anchor cables are arranged, 6.3 meters long and spaced 2000mm x 2000mm apart. The initial anchor cable preload is set at 200 kN. 20mm Φ ordinary mortar anchor rods are used at the side, 2.4 meters long and spaced 1000mm x 1000mm apart. Support parameters are dynamically adjusted based on the surrounding rock pressure data recorded by the S4 hydraulic support frame. If the surrounding rock pressure in a certain area exceeds the design threshold of 1.2 MPa, the anchor cable preload is increased to 250 kN, and the anchor rod spacing is increased to 600mm x 600mm. This support system, together with the S3 temporary support and S4 collaborative support, forms a continuous bearing structure, ensuring that the surrounding rock deformation rate remains stable below 5 mm / day for a long time.

[0066] In step S7, a counter-rotating local ventilator, model FBD No. 6.3 / 2×30, with a rated air volume of 2,000 cubic meters per minute, is deployed at the tunnel entrance. Its outlet is connected via a flexible duct, the end of which moves synchronously with the S4 tunneling equipment, located ≤5 meters from the tunnel face. Ventilation volume is controlled by real-time data from a gas sensor. When the gas concentration exceeds 0.8% after S5 blasting, the ventilator automatically switches to high-speed mode, increasing the air volume to 2,500 cubic meters per minute; it returns to rated air volume when the gas concentration falls below 0.5%. Simultaneously, a wet dust removal blower is activated, handling an air volume of 1,500 cubic meters per minute and achieving a dust removal efficiency of 95%. A spray dust suppression device, operating at a water pressure of 8 MPa and a droplet size of ≤50 microns, keeps dust concentration within the working area below 10 mg / m3, ensuring respiratory safety for S4 rock breaking and S6 support workers and ensuring the accuracy of equipment sensors.

[0067] In step S8, during the pilot tunnel excavation phase (S3), a small rubber-wheeled truck with a 5-ton load capacity and a 2.2-meter wheelbase is used to transport small sections. The truck transports waste rock once every 20 minutes, with a single transport volume of 4 tons. After the main section is expanded (S5), a scraper conveyor (model SGZ630 / 160) with a transport capacity of 500 tons per hour is used. The conveyor head advances 3 meters every 8 hours as the tunnel face advances. The curvature radius of the conveyor in curves is controlled to within ±200 mm of the designed turning radius R of S1. The transport system collects real-time data on single-shift transport volume. Normal operating conditions are 800-1000 tons per shift. If the transport volume falls below 700 tons per shift, the S4 roadheader automatically reduces its cutting speed by 10%, reducing the cutting head speed from 45 rpm to 40 rpm, to prevent waste rock from accumulating and blocking the working surface, ensuring smooth transitions between processes.

[0068] In step S9, fiber Bragg grating displacement sensors with a range of ±50 mm and an accuracy of 0.01 mm are placed on the tunnel roof. Anchor bolt axial force sensors with a range of 0-500 kN and an accuracy of 1 kN are placed on both sides. A gas sensor with a range of 0-4% and an accuracy of 0.01% is installed 10 meters from the tunnel face. All sensor data is transmitted via a 5G network with a transmission delay of ≤20 milliseconds and uploaded to the ground monitoring center in real time. The system automatically generates surrounding rock deformation curves, anchor bolt force curves, and gas concentration change curves. When the monitored surrounding rock displacement rate exceeds 5 mm / day, an early warning mechanism is triggered: a command is sent to the S4 hydraulic support frame to increase the support force by 20%, and a notice to accelerate construction is sent to the S6 support working surface, requiring 80% of the support to be completed within 24 hours. Simultaneously, the monitoring data is input into the S1 pre-research system to modify the design parameters of subsequent tunnel turning sections, such as adjusting the R value or optimizing the support scheme, forming a closed-loop optimization system of "design-construction-monitoring".

[0069] From the above we can know:

[0070] In this invention, the turning trajectory is precisely controlled by preliminary research on geological parameters and surveying and setting out, combined with advance excavation of pilot tunnels and dynamic coordinated support, effectively solving the problem of loosening and damage in traditional turning sections caused by trajectory deviation and long exposure time of surrounding rock. The advance excavation of pilot tunnels reserves space for subsequent excavation. The cutting head of the integrated equipment can rotate horizontally to adapt to the curve excavation, and the support force is dynamically adjusted in conjunction with real-time scanning of surrounding rock deformation data, so that the exposure time of surrounding rock in the turning section construction is shortened from 40-60 minutes in traditional processes to 5-8 minutes, significantly reducing the risk of spalling and roof collapse caused by long-term unsupported exposure of surrounding rock in the turning area. At the same time, the parameter correction program ensures that the turning radius and steering angle are highly consistent with the design, improving the accuracy and safety of turning section construction.

[0071] In the present invention, an intelligent collaborative mode of pre-research-measurement-support-rock breaking-monitoring is adopted. The simultaneous advancement of cutting and support breaks the time intervals between traditional processes, realizes continuous operations from pilot tunnel excavation to permanent support, and greatly improves construction efficiency. The mechanism of real-time monitoring of surrounding rock deformation and dynamic adjustment of support force enables precise matching of support strength with surrounding rock stress state, avoids resource waste or insufficient support caused by "one-size-fits-all" support, and enhances the overall stability of the surrounding rock. The intelligent ventilation and dust removal system ensures the safety of the working environment, the dynamic optimization of the transportation route avoids blockage by waste rock accumulation, and the full-cycle monitoring and feedback form a closed-loop optimization of "design-construction-correction", which fundamentally improves the long-term service reliability of the tunnel and achieves a comprehensive improvement in construction safety, efficiency, and economy.

[0072] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprises" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device that includes the element.

[0073] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A tunnel turning construction method and a tunnel construction method, characterized by: The method comprises the following steps: S1: Obtain the surrounding rock mechanical parameters and groundwater distribution data of the turning section of the roadway through 3D seismic exploration and core drilling. Combined with the design requirements, the turning radius, turning angle, and slope change point coordinates are determined. The results are input into S2 as the basic parameters for trajectory planning. S2: Using a total station-laser tracker combined system, measurement benchmarks are arranged at the starting point, slope change point, and end point of the tunnel based on the S1 parameters. A laser scanner is used to scan the excavated section every 5 meters of excavation, and the deviation value is compared with the designed trajectory. The deviation data is fed back to S1 to correct the preliminary research parameters. S3: A small-section pilot tunnel is excavated ahead of time at the starting point of the turning section. The pilot tunnel profile is expanded 200 mm according to the designed trajectory. Temporary support is immediately applied after excavation. The support strength is adjusted according to the surrounding rock parameters of S1 to provide a safe space for the construction of the S4 main section. S4: Utilizing integrated tunneling equipment, the cantilevered cutting head of the roadheader at the front can rotate ±45° to accommodate turns, and a retractable hydraulic support frame is installed at the rear. As the roadheader cuts, the support frame automatically adjusts its support force based on surrounding rock deformation data scanned in real time by S2, achieving simultaneous "cutting-support" operations and avoiding the risk of surrounding rock exposure between the temporary support in S3 and the subsequent permanent support. S5: With the S3 pilot tunnel as the center, smooth blasting is used to expand the section to the design specifications. The blasting parameters are adjusted according to the strength of the surrounding rock in S1. After blasting, the newly exposed section is covered by the S4 support frame to prevent local spalling caused by the expansion from affecting the permanent support construction in S6. S6: Complete permanent support within 24 hours after the S5 section is expanded: the top is supported by a combination of anchor rods, W-shaped steel belts, and anchor cables, and the side is supported by anchor rods. The anchoring force of the anchor rods and the pre-tightening force of the anchor cables are dynamically adjusted according to the surrounding rock pressure data recorded by the S4 support frame, forming a continuous load-bearing structure with the S3 temporary support and S4 coordinated support. S7: A counter-rotating local ventilator is installed at the tunnel entrance, and the air outlet moves synchronously with the S4 tunneling equipment. The ventilation volume is automatically adjusted according to the gas concentration after the S5 blasting. At the same time, the wet dust removal fan is started to ensure that the dust concentration during the S4 rock breaking and S6 support operations meets the standard, protecting the health of the operators and the operating accuracy of the equipment. S8: During the pilot tunnel excavation phase, small rubber-wheeled vehicles are used to transport waste rock. After the main section is expanded, a scraper conveyor is used. The conveyor head moves forward once every 8 hours as the tunnel face advances. The curvature radius of the conveyor in the turning section matches the turning radius designed in S1. Transport efficiency data is fed back to S4 to adjust the excavation speed. S9: Sensors are placed on the roof and sides of the tunnel, and data is transmitted to the ground monitoring center in real time via the 5G network. When the displacement rate of the surrounding rock exceeds the limit, the system automatically sends instructions to the S4 collaborative support equipment and prompts S6 to speed up the permanent support progress. At the same time, the S1 preliminary research parameters are corrected to form a closed-loop optimization.

2. A tunnel turning construction method and a tunnel construction method according to claim 1, characterized in that: In step S1, before construction, a coverage scan of the tunnel turning section is performed using a three-dimensional seismic exploration system, and in conjunction with a drilling and coring operation, the drilling spacing is controlled at 5 meters to obtain mechanical parameters such as the surrounding rock compressive strength, joint development density, and elastic modulus, and the groundwater infiltration rate and distribution range are simultaneously recorded; based on the requirements of the design drawings and combined with the exploration data, the turning radius R, the steering angle θ, and the three-dimensional coordinates of the slope change point are calculated and determined. The turning radius value is determined based on the tunnel cross-sectional dimensions of 4.5 meters wide and 3.8 meters high and the passability of the tunneling equipment. The minimum R is ≥ 15 meters, and the steering angle error is controlled within ±0.5°.

3. A tunnel turning construction method and a tunnel construction method according to claim 1, characterized in that: In step S2, a high-precision total station and laser tracker combined measurement system is used to bury permanent metal reference points at the starting point, slope change point and end point of the tunnel. The diameter is 20 mm and the burial depth is 500 mm. The coordinate error of the reference points is controlled within ±2 mm. During the excavation process, the laser scanner is started every 5 meters to perform point cloud scanning on the excavated section. The measured point cloud data is aligned with the design trajectory point cloud pre-researched in S1, and the section contour deviation value is extracted. The horizontal and vertical deviations are both controlled within ±50 mm.

4. A tunnel turning construction method and a tunnel construction method according to claim 1, characterized in that: In the step S3, a small-section pilot tunnel is used for advance excavation at the starting position of the turning section. The pilot tunnel has a specification of 2.5 meters in width and 2.8 meters in height. Its outline is expanded by 200 mm according to the designed turning trajectory to reserve space for the expansion of the main section. After the pilot tunnel is excavated, temporary support is immediately applied: Φ20 mm mortar anchor rods with a length of 2.2 meters are used and arranged at a spacing of 1000 mm × 1000 mm. The exposed length of the anchor rods is controlled at 150 mm. The anchor rods are hung with a 6 mm diameter steel mesh with a grid of 200 mm × 200 mm, and then C20 concrete with a thickness of 100 mm is sprayed. If the S1 preliminary study shows that the density of surrounding rock joints exceeds 3 per square meter, the anchor rod spacing is increased to 800 mm × 800 mm, and the thickness of the sprayed concrete is increased to 120 mm. After the temporary support is completed, a stable working space is provided for the construction of the S4 main section, with a clearance height ≥ 2.5 meters and a width ≥ 2.2 meters.

5. A tunnel turning construction method and a tunnel construction method according to claim 1, characterized in that: In step S4, a laser scanner is used to scan the excavated section every 5 m for a point cloud, and the measured point cloud is registered with the theoretical point cloud of the designed trajectory to extract the absolute displacement and deformation rate of each monitoring point on the surrounding rock surface; When the laser scanner detects that the deformation rate v of the surrounding rock in a certain area exceeds the reference value v0, the control module calls the correlation law of "deformation rate-support force" under similar surrounding rock conditions in the historical database, and combines it with the real-time load status of the current hydraulic support frame to calculate the support force increment ΔF that needs to be adjusted. If the deformation rate is lower than v0, the support force is appropriately reduced to reduce equipment energy consumption. The dynamic matching formula of “deformation rate-support force” is: in: F represents the real-time support force that needs to be applied currently; F0 represents the initial set reference support force; k represents the sensitivity coefficient of surrounding rock; v represents the deformation rate of the surrounding rock monitored in real time by the laser scanner; v0 represents the design safety basis deformation rate.

6. A tunnel turning construction method and a tunnel construction method according to claim 1, characterized in that: In step S5, the cross section is expanded to the designed specification of 4.5 meters wide and 3.8 meters high using a smooth blasting process with the S3 pilot tunnel as the center. The blasting holes are arranged into three categories: slot holes, auxiliary holes, and peripheral holes. The slot holes adopt a wedge-shaped slot, with a hole depth of 2.5 meters, a hole diameter of 42 mm, a hole spacing of 400 mm, and a charge of 2.5 kg per hole. Auxiliary holes were arranged along the periphery of the slot hole, with a depth of 2.4 meters, a diameter of 42 mm, and a spacing of 600 mm. Each hole was charged with 2 kg of explosives. Peripheral holes, closely following the design contour, were 2.3 meters deep, 42 mm in diameter, and 350 mm in spacing, using an interval charging structure. Blasting parameters were dynamically adjusted based on the surrounding rock strength pre-studied in S1: if the surrounding rock compressive strength was greater than 80 MPa, the spacing between peripheral holes was increased to 400 mm, and the charge per hole was increased to 1 kg. If the surrounding rock compressive strength was less than 40 MPa, the spacing between peripheral holes was reduced to 300 mm, and the charge per hole was reduced to 0.6 kg. The detonation sequence was slot hole → auxiliary hole → peripheral hole, and millisecond delay detonators were used to control blasting vibrations. Immediately after blasting, the S4 hydraulic support frame was activated, with its retractable support arms covering the newly exposed section. By applying a support force of 800-1000 kN, it constrained the surrounding rock surface, preventing local spalling caused by excavation expansion and providing stable working conditions for the S6 permanent support construction.

7. A tunneling tunnel turning construction method and a tunnel construction method according to claim 1, characterized in that: In the step S6, permanent support is completed within 24 hours after the main section of S5 is expanded to the design specification of 4.5 meters in width and 3.8 meters in height; the top uses Φ22 mm left-handed anchor rods without longitudinal reinforcement, with a length of 2.8 meters and arranged at a spacing of 800 mm × 800 mm, and the tail of the anchor rod is equipped with a W-shaped steel belt with a thickness of 3 mm and a width of 250 mm; at the same time, Φ17.8 mm steel strand anchor cables are arranged with a length of 6.3 meters and a spacing of 2000 mm × 2000 mm, and the anchor cable preload force is initially set to 200 kN; the side uses Φ20 mm ordinary mortar anchor rods with a length of 2.4 meters and a spacing of 1000 mm × 1000 mm.

8. The tunnel turning construction method and tunnel construction method according to claim 1, characterized in that: In step S7, a counter-rotating local ventilator, model FBD No. 6.3 / 2×30, with a rated air volume of 2,000 cubic meters per minute, is arranged at the tunnel entrance. The air outlet is connected through a flexible duct, and the end of the duct moves synchronously with the S4 tunneling equipment, with a distance of ≤5 meters from the tunnel face. The ventilation volume is controlled by real-time monitoring data of the gas sensor. When the gas concentration exceeds 0.8% after the S5 blasting, the ventilator automatically switches to high-speed mode and the air volume is increased to 2,500 cubic meters per minute. When the gas concentration is lower than 0.5%, the rated air volume is restored. At the same time, a wet dust removal fan is started, with a processing air volume of 1,500 cubic meters per minute and a dust removal efficiency of 95%. The dust concentration on the working surface is controlled below 10 mg / cubic meter through a spray dust suppression device with a water pressure of 8 MPa and a droplet size of ≤50 microns, thereby ensuring the respiratory safety of the S4 rock breaking and S6 support workers and the accuracy of the equipment sensors.

9. A tunneling tunnel turning construction method and a tunnel construction method according to claim 1, characterized in that: In step S8, during the pilot tunnel excavation phase, i.e., phase S3, a small rubber-wheeled transport vehicle with a load capacity of 5 tons and a wheelbase of 2.2 meters is used to transport small sections. The vehicle transports waste rock once every 20 minutes, with a single transport volume of 4 tons. After the main section is expanded, i.e., phase S5, a scraper conveyor is used, model SGZ630 / 160, with a transport capacity of 500 tons / hour. The conveyor head moves forward once every 8 hours as the tunnel face advances, with a forward movement distance of 3 meters. The curvature radius of the conveyor in the turning section is controlled within ±200 mm of the designed turning radius R of S1. The transportation system collects single-shift transportation volume data in real time. The normal operating condition is 800-1000 tons / shift. If the transportation volume is less than 700 tons / shift, the S4 roadheader automatically reduces the cutting speed by 10%, and the cutting head speed drops from 45 rpm to 40 rpm.

10. The tunneling tunnel turning construction method and tunnel construction method according to claim 1, characterized in that: In step S9, a fiber Bragg grating displacement sensor is arranged on the tunnel roof with a range of ±50 mm and an accuracy of 0.01 mm. Anchor axial force sensors are arranged on both sides with a range of 0-500 kN and an accuracy of 1 kN. At the same time, a gas sensor is installed 10 meters away from the tunnel face with a range of 0-4% and an accuracy of 0.01%.

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