Contact channel shield construction method

Abstract

The invention discloses a contact channel shield construction method, which relates to the technical field of tunnel construction and comprises the following steps: during use, performing end reinforcement operation on a preset construction area in a tunnel; wherein the contact channel is formed in a preset construction area, according to the preset construction area, a tunnel portal steel pipe piece for installing the contact channel and a shield tunneling machine, tunnel portal grouting is conducted on a tunnel portal, a reference ring is installed at the shield tail position of the shield tunneling machine, an anti-twisting block is welded to the periphery of the shield tunneling machine, and after temporary sealing of the tunnel portal is completed, the shield tunneling machine is controlled to conduct shield tunneling operation. By means of the construction method, construction of the connecting channel can be achieved on the basis that a drilling and blasting method is not needed for excavating the connecting channel, the construction procedure is simplified, meanwhile, construction such as lining or supporting does not need to be conducted on the connecting channel, and the construction efficiency can be improved and the construction progress can be ensured when the construction method is specifically used.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel construction, and particularly to a shield construction method for a connection passage. Background Art

[0002] The shield construction technology for connection passages is an important technology in the field of tunnel engineering, and its development process is closely related to the development of urban underground space. With the acceleration of urbanization, the demand for underground projects such as subway tunnels, highway tunnels, utility tunnels, and deep-buried drainage tunnels is increasing day by day. As a key structure connecting these main tunnels, the construction technology of connection passages has also developed accordingly. Connection passages not only provide safe evacuation passages in case of emergencies but also undertake multiple functions such as drainage, maintenance, and fire rescue. The shield construction technology, with its characteristics of high efficiency and safety, has gradually become the preferred method for connection passage construction.

[0003] Currently, the shield construction technology for connection passages has been widely applied in many countries and regions. This technology forms a stable passage structure by pushing a shield machine underground and assembling precast concrete segments. The shield machine is pushed forward by jacking pressure, the cutting device excavates the soil body, and the soil discharging device is responsible for transporting the slurry out. This method significantly improves the construction efficiency, reduces the safety risk, and decreases the impact on the environment compared with the traditional manual or mining method excavation. However, despite the certain progress made by the shield construction technology in connection passage construction, there are still some technical challenges.

[0004] In the prior art, when constructing a connection passage, the drill and blast method or other methods are usually adopted. When using the drill and blast method for construction, due to the need for operations such as lining and blasting during the construction process, the construction period is long, which affects the overall construction progress. Summary of the Invention

[0005] The main object of the present invention is to propose a shield construction method for a connection passage, aiming to solve the technical problem that in the prior art, when constructing a connection passage, the drill and blast method or other methods are usually adopted. When using the drill and blast method for construction, due to the need for operations such as lining and blasting during the construction process, the construction period is long, which affects the overall construction progress.

[0006] To achieve the above object, in a first aspect, a shield construction method for a connection passage proposed by the present invention includes the following steps:

[0007] Carry out end reinforcement operation on a preset construction area in the tunnel; wherein, the connection passage is formed within the preset construction area;

[0008] Install the portal steel segments of the connection passage and the shield machine according to the preset construction area;

[0009] Grout the portal.

[0010] Install a reference ring at the tail position of the shield machine.

[0011] Weld anti-twist blocks on the outer periphery of the shield machine.

[0012] After completing the temporary sealing of the portal, control the shield machine to carry out shield tunneling operations.

[0013] In one embodiment, the step of performing end reinforcement operations on a preset construction area in the tunnel includes:

[0014] Use a three-axis mixing pile to perform end reinforcement operations on the preset construction area in the tunnel.

[0015] In one embodiment, before the step of using a three-axis mixing pile to perform end reinforcement operations on the preset construction area in the tunnel, it further includes:

[0016] Obtain the preset construction area according to the preset construction data; wherein, the preset construction area is an area at least 3 meters outside the periphery of the connection passage, 3 meters below the arch bottom, and 4 meters above the arch top. [[ID=,23]]

[0017] In one embodiment, the step of obtaining the preset construction area according to the preset construction data includes:

[0018] According to the preset construction data, strongly reinforce the area at least 3 meters outside the periphery of the connection passage and 3 meters below the arch bottom, and weakly reinforce the area 4 meters above the arch top to obtain the preset construction area.

[0019] In one embodiment, before the step of installing the portal steel segments of the connection passage and the shield machine according to the preset construction area, the method further includes:

[0020] Install auxiliary tunneling equipment in the tunnel; wherein, the auxiliary tunneling equipment includes tracks, lighting systems, walkway boards, and electrical systems.

[0021] In one embodiment, after the step of installing auxiliary tunneling equipment in the tunnel, it further includes:

[0022] Adjust the gauge of the track according to the preset transportation requirements.

[0023] In one embodiment, the step of installing the portal steel segments of the connection passage and the shield machine according to the preset construction area includes:

[0024] Install steel segments at the starting position and receiving position of the tunnel according to the preset construction area.

[0025] Perform welding operations on the steel pipe segments;

[0026] After completing the welding operations, install the shield machine at the starting position.

[0027] In one embodiment, the step of performing welding operations on the steel pipe segments includes:

[0028] Perform welding operations on the steel pipe segments using a hierarchical welding method.

[0029] In one embodiment, the step of installing the shield machine at the starting position after completing the welding operations includes:

[0030] After completing the welding operations, process and detect the weld seams, and install the shield machine at the starting position.

[0031] In one embodiment, after the step of controlling the shield machine to perform shield tunneling operations after completing the temporary sealing of the portal, the method further includes:

[0032] Perform grouting operations on the portal of the connecting passage.

[0033] When the technical solution of the present invention is used, perform end reinforcement operations on the preset construction area in the tunnel; wherein, the connecting passage is formed within the preset construction area. According to the preset construction area, install the portal steel pipe segments and the shield machine of the connecting passage, perform portal grouting on the portal, install a reference ring at the tail position of the shield machine, weld anti-twist blocks on the outer periphery of the shield machine. After completing the temporary sealing of the portal, control the shield machine to perform shield tunneling operations, so that the present invention can realize the construction of the connecting passage without using the drill and blast method for excavating the connecting passage, which not only simplifies the construction process, but also, because there is no need to perform construction such as lining or support on the connecting passage, the present invention can improve the construction efficiency and ensure the construction progress when specifically used. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0035] Figure 1 It is a flowchart of the shield tunneling construction method for the connecting passage provided by the present invention;

[0036] Figure 2 For Figure 1 It is a flowchart of step S100 exemplified in

[0037] Figure 3 For Figure 1 the flowchart of step S200 in the example;

[0038] Figure 4 It is the flowchart of some specific embodiments of the shield construction method for the connection passage in the example of the present invention.

[0039] The realization of the object of the present invention, functional features and advantages will be further described with reference to the embodiments and the accompanying drawings. Specific Embodiments

[0040] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0041] It should be noted that if there are directional indications (such as up, down, left, right, front, back...) involved in the embodiments of the present invention, the directional indications are only used to explain the relative positional relationship and movement conditions between components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0042] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, if "and / or" or "and / or" appears throughout the text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or the solution where A and B are satisfied simultaneously. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0043] The present invention proposes a shield construction method for a connection passage.

[0044] Please refer to Figures 1 to 4 , for the convenience of understanding, this shield construction method for a connection passage includes the following steps:

[0045] S100. Conduct end reinforcement operations on the preset construction area in the tunnel; wherein, the connection passage is formed within the preset construction area.

[0046] Specifically, the grouting reinforcement method can be used to reinforce the preset construction area. The grouting material can be selected as the cement-sodium silicate double-fluid grout, the grouting pressure is controlled at 0.5 MPa - 1.0 MPa, and the grouting time is 24 - 48 hours. The reinforcement range should cover at least 2 meters around the connection passage to ensure construction safety. The strength of the reinforced soil should reach 2 MPa - 3 MPa to meet the requirements of subsequent construction.

[0047] S200. Install the portal steel segments of the connection passage and the shield machine according to the preset construction area.

[0048] Specifically, the specific process of installing the portal steel segments in step S200 is as follows: First, use a total station to accurately measure the portal position, with the error controlled within ±5 mm; then use a special lifting tool to hoist the portal steel segments in place to ensure tight fitting with the main tunnel segments; then use high-strength bolts to fix the portal steel segments to the main tunnel segments, with the torque controlled at 800 N·m - 1000 N·m; finally, apply sealant at the joint between the portal steel segments and the main tunnel segments to prevent water seepage.

[0049] The installation process of the shield machine is as follows: Assemble the components of the shield machine in advance on the ground, including the cutter head, main machine, propulsion system, etc.; use a large crane to hoist the assembled shield machine as a whole into the tunnel; use a laser positioning system to accurately align the shield machine with the center of the portal, with the deviation controlled within 10 mm; use a temporary support frame to fix the shield machine to ensure its stability.

[0050] S300. Perform portal grouting on the portal.

[0051] The grouting material is selected as the double-fluid grout, with the ratio of cement: sodium silicate = 1:1, and the grouting pressure is controlled at 0.3 - 0.5 MPa. Grouting holes are evenly arranged around the portal, with a spacing of 0.5 m, and the grouting volume is 80% of the designed volume; supplementary grouting is carried out 24 hours later, and the grouting volume is 20% of the designed volume to ensure full filling.

[0052] After the grouting is completed, quality inspections should be carried out, including ultrasonic testing and core sampling, to ensure that the grouting density reaches more than 95%.

[0053] S400. Install a reference ring at the tail position of the shield machine.

[0054] Specifically, a Q345 steel is selected to fabricate the reference ring with a thickness of 20 mm and a width of 300 mm. The reference ring is precisely machined according to the shield tail diameter, and the tolerance is controlled within ±1 mm. A laser rangefinder is used to determine the installation position of the reference ring, and the distance from the shield tail end face is controlled within 50 mm. The reference ring is fixed to the shield tail by using the all-position welding method, and the weld thickness is not less than 12 mm. The installation of the reference ring can provide an accurate reference for the subsequent segment installation and improve the construction accuracy.

[0055] S500. Weld anti-twist blocks on the outer periphery of the shield machine.

[0056] Specifically, by setting the anti-twist blocks, the present invention can prevent the shield machine from twisting during use, ensuring the normal tunneling of the shield machine.

[0057] S600. After completing the temporary seal of the portal, control the shield machine to carry out shield construction.

[0058] Through the above steps, the shield construction method for the connection passage of the present invention can effectively shorten the construction period and improve the construction efficiency. Compared with the traditional drill and blast method, this method has the advantages of strong construction continuity, no need for repeated lining and blasting operations; precise control of construction parameters, improving construction quality and safety; reducing the disturbance to the surrounding environment, being applicable to complex geological conditions; high degree of automation, reducing manual operation errors, etc.

[0059] The shield construction method for the connection passage provided by the present invention effectively solves the technical problems of the long construction period and the influence on the overall construction progress of the traditional drill and blast method through systematic construction steps, including end reinforcement, portal installation, grouting treatment, reference ring installation, anti-twist block welding, and shield operation control, etc. This method not only improves the construction efficiency but also ensures the construction quality and safety, providing reliable technical support for the efficient construction of the connection passage. At the same time, it can also realize the construction of the connection passage without using the drill and blast method for excavation. This not only simplifies the construction process but also, since there is no need for construction such as lining or support for the connection passage, the present invention can improve the construction efficiency and ensure the construction progress when specifically used.

[0060] In one embodiment, step S100 includes:

[0061] S110. Use a triple-axis mixing pile to carry out end reinforcement operations on the preset construction area in the tunnel.

[0062] The end reinforcement operation refers to pre-reinforcing the soil mass in front of and around the tunnel excavation face to improve the soil strength and prevent safety accidents such as collapse and deformation during the excavation process.

[0063] Specifically, in step S110, a triple-axis mixing pile is used to carry out end reinforcement operations on the preset construction area within the tunnel. The triple-axis mixing pile is a ground treatment technique that injects solidifying materials such as cement slurry into the soil through special equipment and mixes them with the soil to form a pile body with a certain strength, thereby improving the overall strength and stability of the soil. The preset construction area refers to a specific area that needs to be reinforced, which is determined in advance according to factors such as tunnel geological conditions and construction requirements, and usually includes the soil within a certain range in front of the tunnel excavation face.

[0064] More specifically, first, according to the scope of the preset construction area within the tunnel, determine the layout position and quantity of the mixing piles. Usually, the mixing piles are arranged in a plum blossom shape or a square grid shape, and the pile spacing is 0.8 - 1.2 meters to ensure the continuity and integrity of the reinforcement effect. Secondly, position the triple-axis mixing pile equipment, which mainly consists of a drill rig, a mixer, a grouting system, and a control system. The mixer consists of three parallel drill pipes, and each drill pipe is equipped with mixing blades, which can carry out drilling and mixing operations simultaneously. Then, start the equipment, and let the triple-axis mixer drill into the soil at a rotation speed of 5 - 10 revolutions per minute, while injecting the cement slurry into the soil through the grouting system at a pressure of 0.3MPa - 0.5MPa. The water-cement ratio of the cement slurry is usually controlled between 0.5 - 0.6, and the cement dosage is 350kg / m 3 [[ID=I5]]-450kg / m 3 . The drilling speed is controlled at 0.3m / min - 0.5m / min to ensure uniform mixing. Finally, when drilling reaches the design depth, lift the mixer at the same or slightly lower speed, while continuing to inject the cement slurry and carry out secondary mixing until the mixer completely withdraws from the soil. During the whole process, parameters such as the grouting volume, mixing depth, and mixing time should be monitored in real time to ensure the reinforcement quality.

[0065] For sandy soil layers with a relatively high water content, the construction parameters of the triple-axis mixing pile need to be appropriately adjusted: the water-cement ratio of the cement slurry is reduced to 0.4 - 0.5, and the cement dosage is increased to 450kg / m 3 -550kg / m 3 , and at the same time, 5% - 8% of an expansion agent is added to improve the impermeability and stability of the slurry. The mixing speed is increased to 8 - 12 revolutions per minute, and the drilling speed is reduced to 0.2m / min - 0.3m / min to increase the mixing time and ensure full mixing of the cement slurry with the high-water-content soil. In addition, during the mixing process, the grouting can be intermittently stopped for 2 - 3 minutes to allow the injected cement slurry sufficient time to react with the soil, and then continue grouting and mixing. Using the "intermittent grouting method" can effectively improve the diffusion effect and solidification quality of the cement slurry in the high-water-content soil.

[0066] For the clay layer with high viscosity, the construction parameters of the triaxial mixing pile are adjusted as follows: 3%-5% water reducer is added to the cement slurry to reduce the viscosity of the slurry, improve fluidity and permeability; the mixing speed is increased to 10-15 revolutions per minute, and the drilling speed is further reduced to 0.1m / min-0.2m / min; at the same time, 10%-15% fly ash is added to the cement slurry, which can not only reduce costs, but also improve the workability and late strength of the slurry. In addition, for particularly viscous soil layers, the construction process of "pre-drilling - grouting - mixing" can be adopted, that is, first drill to the design depth with an ordinary drill bit to form a pre-drilled hole with a diameter slightly smaller than the mixing pile, and then carry out grouting and mixing, which can greatly reduce the mixing resistance and improve the construction efficiency and quality.

[0067] By carrying out end reinforcement operations with triaxial mixing piles, the strength and stability of the soil in the tunnel construction area can be significantly improved. According to the on-site test data, the compressive strength of the soil after reinforcement treatment can be increased by 2-3 times, and the permeability coefficient is reduced by 1-2 orders of magnitude, effectively controlling the seepage and erosion of groundwater. At the same time, a "soil-pile" composite system with strong integrity and high stiffness is formed in the reinforcement area, which can effectively resist tunneling within a safe range (usually less than 20mm), greatly reducing the risks of collapse and water inrush.

[0068] In addition, compared with the traditional grouting reinforcement method, the triaxial mixing pile technology has the characteristics of more uniform mixing, more stable reinforcement effect and stronger adaptability. The three parallel drill pipes work simultaneously, which not only improves the construction efficiency, shortens the construction period, but also forms a larger cross-section of the mixing pile, a wider coverage area, and a more significant reinforcement effect. Especially for tunnel construction under complex geological conditions, the triaxial mixing pile technology can flexibly adjust construction parameters according to different soil layer characteristics to ensure that the reinforcement effect meets the design requirements.

[0069] In this embodiment, by adopting the triaxial mixing pile technology to carry out end reinforcement operations on the preset construction area in the tunnel, not only the safety and stability of tunnel construction are significantly improved, effectively solving the technical problems of safety hazards such as easy collapse and deformation in traditional tunnel construction, but also it has the advantages of strong adaptability and significant economic benefits, providing a reliable technical guarantee for the safe and efficient construction of tunnel projects.

[0070] In one embodiment, before step S110, it further includes:

[0071] S120. Obtain the preset construction area according to the preset construction data; wherein, the preset construction area is the area at least 3 meters outside the periphery of the connection passage, 3 meters below the arch bottom and 4 meters above the arch top.

[0072] In this embodiment, the exemplary preset construction materials refer to various technical materials collected and sorted during the preliminary preparation stage of tunnel construction, including but not limited to geological exploration reports, hydrogeological data, tunnel design drawings, construction organization design plans, etc. The preset construction materials provide the necessary technical basis for determining the preset construction area. By analyzing and studying these materials, key information such as the geological conditions, geotechnical properties, and groundwater distribution along the tunnel can be accurately grasped, so as to scientifically and reasonably determine the area range that needs to be reinforced.

[0073] The connection passage refers to the horizontal connecting passage built between parallel tunnels, which is mainly used for functions such as personnel evacuation, equipment maintenance, and ventilation during tunnel operation. Since the excavation of the connection passage will damage the structural integrity of the original tunnel and form a stress concentration area, the surrounding area of the connection passage is often a weak link in tunnel construction and requires special reinforcement treatment.

[0074] The preset construction area is the area at least 3 meters outside the periphery of the connection passage, 3 meters below the arch bottom, and 4 meters above the arch top. The determination of this range is based on the following technical considerations:

[0075] The range of at least 3 meters outside the periphery of the connection passage is determined based on the stress diffusion theory. According to the principles of geomechanics, when a connection passage is excavated in a tunnel, the originally evenly distributed stress will redistribute around the connection passage, forming a stress concentration area. Theoretical calculations and numerical simulation analyses show that the influence range of this stress concentration area is approximately 2.5 - 3.5 meters outside the periphery of the connection passage. Therefore, determining the preset construction area as at least 3 meters outside the periphery of the connection passage can cover the main stress concentration area and ensure the reinforcement effect.

[0076] The range of 3 meters below the arch bottom is considered because the load pressure borne by the tunnel bottom is relatively large and may be affected by groundwater, making it prone to uplift or softening phenomena. Through statistical analysis of multiple similar engineering cases, the soil deformation within the range of 2.5 - 3.5 meters below the arch bottom usually accounts for 40% - 60% of the total deformation. Therefore, including 3 meters below the arch bottom in the preset construction area can effectively control the bottom deformation and improve the overall stability.

[0077] The range of 4 meters above the arch top is determined based on the self-stabilization ability of the soil above the arch top and the possible loosening zone range. After the tunnel is excavated, a natural arch will form in the soil above the arch top, and its height is related to factors such as the tunnel span and soil properties. According to empirical formula calculations, for common tunnel cross-section sizes and geological conditions, the height of the natural arch is approximately 3.5 - 4.5 meters. Including 4 meters above the arch top in the preset construction area can ensure that the soil within the natural arch range is effectively reinforced and prevent the arch top from collapsing.

[0078] Specifically, for the geological conditions mainly composed of sandy soil layers, the determination process of the preset construction area is as follows: First, collect and analyze the geological exploration report to determine the basic information such as the soil layer distribution and physical and mechanical parameters around the connection tunnel. Second, use finite element analysis software (such as FLAC3D or MIDAS GTS NX) to establish a three-dimensional numerical model to simulate the stress distribution and deformation characteristics during the excavation process of the connection tunnel. The physical and mechanical parameters of the soil in the model are adopted from the results of laboratory tests, and the boundary conditions are set according to the actual engineering situation. Through numerical simulation calculations, the displacement field and stress field distribution nephograms of the surrounding soil after the excavation of the connection tunnel are obtained. The analysis results show that under the sandy soil layer conditions, the stress concentration area is mainly distributed within 3.2 meters outside the perimeter of the connection tunnel, the obvious deformation area under the arch bottom is 2.8 meters, and the height of the potential loosening area above the arch top is 3.9 meters. Considering the safety margin, the preset construction area is finally determined as the area within 3.5 meters outside the perimeter of the connection tunnel, 3 meters below the arch bottom, and 4 meters above the arch top.

[0079] Certainly, for the geological conditions mainly composed of clay soil layers, the determination process of the preset construction area is different: First, in addition to the conventional geological exploration data, additional soil rheological property tests are required to obtain data such as the long-term strength and creep parameters of the clay. Second, a viscoelastic-plastic constitutive model is adopted in the numerical simulation to consider the time-dependent deformation characteristics of the clay. The simulation results show that under the clay soil layer conditions, the stress concentration area is slightly smaller, about 2.8 meters outside the perimeter of the connection tunnel, but the deformation development process is relatively slow and lasts for a long time. The deformation area under the arch bottom is 3.2 meters, and the height of the potential loosening area above the arch top is 4.2 meters. Considering the long-term stability problem of the clay, the preset construction area is finally determined as the area within 3 meters outside the perimeter of the connection tunnel, 3.5 meters below the arch bottom, and 4.5 meters above the arch top.

[0080] In addition, for the special geological conditions of composite strata (sandy soil in the upper part and clay in the lower part), the determination of the preset construction area is more complex: First, detailed stratified exploration is required to clarify the thickness, physical and mechanical parameters of each soil layer and their spatial distribution laws. Second, a stratified modeling method is adopted in the numerical simulation, and different constitutive models and parameters are used for different soil layers. The simulation results show that under the composite strata conditions, the stress concentration area is asymmetrically distributed, about 3.3 meters outside the perimeter of the connection tunnel on the sandy soil side and about 2.9 meters on the clay side. The deformation area under the arch bottom is 3.1 meters, and the height of the potential loosening area above the arch top is 4.1 meters. Based on the "principle of taking the larger value", the preset construction area is finally determined as the area within 3.5 meters outside the perimeter of the connection tunnel, 3.5 meters below the arch bottom, and 4.5 meters above the arch top.

[0081] By determining the preset construction area, it is possible to provide accurate guidance on the construction scope for subsequent jet grouting pile reinforcement operations, avoiding problems of insufficient or excessive reinforcement. The precise demarcation of the preset construction area ensures that the reinforcement measures can cover all potential unstable areas, while not causing waste of resources, achieving the best balance between safety and economy.

[0082] According to the statistics of engineering practice data, after the reinforcement treatment is carried out in the preset construction area determined by the method of the present invention, the maximum deformation amount during the construction of the connection passage is reduced by 35%-45% compared with the range determined by the traditional empirical method, the incidence of safety accidents is reduced by more than 60%, and the construction efficiency is increased by 25%-30%. Especially for tunnel projects under complex geological conditions, the advantages of this method are more obvious. It can flexibly adjust the range of the preset construction area according to the characteristics of different geological conditions to ensure that the reinforcement effect meets the engineering safety requirements.

[0083] By analyzing the preset construction data, accurately determining the preset construction area, and on this basis, using the jet grouting pile technology for end reinforcement operations, a systematic, efficient and reliable tunnel construction method is formed. It not only significantly improves the safety and stability of tunnel construction, but also effectively solves the technical problems of potential safety hazards such as collapse and deformation that are prone to occur in the connection passage area during traditional tunnel construction.

[0084] In one embodiment, step S120 includes:

[0085] According to the preset construction data, strongly reinforce the area at least 3 meters outside the circumference of the connection passage and 3 meters below the arch bottom, and weakly reinforce the area 4 meters above the arch top to obtain the preset construction area.

[0086] In one embodiment, before step S200, the method further includes:

[0087] S700. Install auxiliary tunneling equipment in the tunnel; wherein, the auxiliary tunneling equipment includes tracks, lighting systems, walkway boards and electrical systems.

[0088] Auxiliary tunneling equipment refers to various facilities and systems that provide support and guarantee for tunnel tunneling construction, mainly including tracks, lighting systems, walkway boards and electrical systems, etc.

[0089] Specifically, the track refers to the rail system laid on the invert of the tunnel, which is used to transport tunneling equipment, construction materials, muck, etc. The installation of the track needs to follow the following steps and technical requirements: First, according to the tunnel section and construction plan, determine the layout position and gauge of the track. For a single-track tunnel, the gauge is usually 600 mm, and 43 kg / m rails are used. For a double-track tunnel, a double-track layout can be adopted with the same gauge. Second, a C20 concrete foundation layer with a thickness of 150 - 200 mm can be poured to ensure the flatness and stability of the track foundation. Then, install sleepers on the foundation layer. The sleeper spacing is usually 600 mm, and the materials can be selected from wood or precast concrete. Next, fix the rails on the sleepers and use spikes or rail fasteners for connection to ensure firm connection. Finally, precisely adjust the track so that its longitudinal slope is controlled within 3‰ and the lateral horizontal deviation does not exceed 5 mm to meet the driving requirements of transportation equipment.

[0090] In some preferred embodiments, for tunnel sections with better rock quality, the following parameters are adopted for track installation: the gauge is 900 mm, 22 kg / m rails are used, the sleepers are precast concrete, the spacing is 600 mm, the foundation is C20 concrete with a thickness of 150 mm. The track connection uses fishplate bolts, and an expansion joint is set every 50 m to accommodate the track expansion caused by temperature changes. A refuge cave with a size of 1.5 m × 1.0 m × 2.0 m is set every 30 m on both sides of the track for construction workers to temporarily avoid when the equipment passes.

[0091] Of course, in some other embodiments, for tunnel sections with soft surrounding rock, the track installation parameters are adjusted as follows: the gauge remains 900 mm, but 30 kg / m rails are used to bear greater transportation loads. The sleeper spacing is reduced to 500 mm, the foundation is C25 concrete, the thickness is increased to 200 mm, and a 100 - mm - thick crushed stone cushion layer is added under the foundation to enhance the drainage and stability of the foundation. The track connection adopts welding to improve the integrity and smoothness of the track. At the same time, drainage ditches with a cross - section size of 300 mm × 300 mm and a slope of 5‰ are added on both sides of the track in the soft surrounding rock section to ensure that the accumulated water in the tunnel can be drained in time to prevent the accumulated water from eroding and softening the track foundation.

[0092] The lighting system refers to the lighting equipment installed in the tunnel and its control system, which is used to provide necessary lighting conditions for tunnel construction. When installing the lighting system, the following factors need to be considered: First, according to the tunnel cross-section and construction requirements, determine the type, quantity, and layout position of the lighting fixtures. Usually, explosion-proof LED work lights or fluorescent lights with a power of 36W or 50W are used. Second, the lighting fixtures are arranged longitudinally along the tunnel, with a spacing usually of 10 - 15m and an installation height of 0.5m - 1.0m below the tunnel vault. The fixtures can be fixed directly on the tunnel lining using expansion bolts or suspended and installed using special brackets. Then, lay the power supply line for the lighting system, using armored cables or rubber-sheathed cables with specifications of YJV-3×4+1×2.5mm 2 or YC-3×6+1×4mm 2 , and the cable is laid along one side wall of the tunnel at a height of 2.0 - 2.5m from the ground and fixed using cable clips with a spacing of 1.0 - 1.5m. Finally, install the lighting control system, including distribution boxes, switches, protection devices, etc. The distribution box is usually set at the tunnel entrance or at positions every 200m - 300m, equipped with a leakage protector and an overload protection device to ensure electrical safety.

[0093] Of course, in some alternative embodiments, for long-distance tunnel projects, the lighting system adopts a zoning control method: the entire tunnel is divided into several lighting sections, each section being 100m - 150m in length, and the lighting in each section can be controlled independently. The lighting fixtures are explosion-proof LED work lights with a power of 50W, a color rendering index Ra≥80, a color temperature of 5000K, and a fixture protection level of IP65. The fixture spacing is 12m, staggered on both sides of the tunnel, and the installation height is 0.8m below the vault. The power supply line uses YJV-3×6+1×4mm 2 armored cable, laid along the right side wall of the tunnel at a height of 2.2m from the ground. Each lighting section is provided with an explosion-proof lighting distribution box containing components such as a circuit breaker, a leakage protector, and a contactor. In addition, lighting intensity automatic adjustment devices are set at the tunnel entrance and at the boundaries of each partition. According to the difference in light intensity inside and outside the tunnel, the lighting brightness is automatically adjusted to reduce the adaptation time between light and darkness and improve construction safety.

[0094] The walkway slab refers to the pedestrian passage facility installed in the tunnel, which is used to ensure the safe passage of construction workers. When installing the walkway slab, the following requirements need to be met: First, according to the tunnel cross-section and construction plan, determine the position and width of the walkway slab. Usually, the walkway slab is set on one side or both sides of the track, with a width of not less than 0.8m. Second, the material of the walkway slab can be selected from precast reinforced concrete slabs, steel grating slabs, or wooden boards, with a thickness usually of 50mm - 80mm and a load-bearing capacity of not less than 3kN / m 2. Then, reserve a walkway slab support structure at the bottom of the tunnel. It can be a concrete step or a steel bracket, with a height usually of 150 - 200 mm above the rail surface, ensuring that the walkway slab is higher than the rail surface for easy drainage and personnel passage. Next, install the walkway slab on the support structure. The adjacent walkway slabs are connected by lapping or mortise and tenon joints to ensure firm connection and a flat surface. Finally, install a guardrail on the outer edge of the walkway slab, with a height not less than 1.0 m and a column spacing not greater than 2.0 m to ensure the safety of construction personnel during passage.

[0095] Certainly, in some alternative embodiments, for tunnel projects with a high groundwater level, the walkway slab is specially treated as follows: The walkway slab is selected as a hot-dip galvanized steel grating plate with a specification of 30 mm × 100 mm and a thickness of 5 mm. The surface is treated with anti-slip treatment, and the anti-slip grade is not less than R11. The width of the walkway slab is 1.0 m and it is set on the right side of the track. The support structure is a bracket made of hot-dip galvanized angle steel with a spacing of 1.5 m. The bottom of the bracket is fixed to the concrete foundation at the bottom of the tunnel by expansion bolts. The walkway slab and the bracket are connected by bolts, and 4 M12 bolts are set at each connection point. A guardrail with a height of 1.2 m is installed outside the walkway slab. The guardrail is made of φ48 mm hot-dip galvanized steel pipe, and the column spacing is 1.5 m. The guardrail is provided with upper, middle, and lower crossbars. In addition, a drainage ditch with a cross-section of 400 mm × 400 mm and a slope of 8‰ is set under the walkway slab. A sump with a size of 600 mm × 600 mm × 800 mm is set every 50 m to ensure that groundwater can be drained in time and prevent the walkway slab from being flooded.

[0096] The circuit system refers to the equipment and lines that provide power supply for tunnel construction, including transformers, distribution boxes, cables, sockets, etc. The installation of the circuit system needs to follow the following steps and technical requirements: First, determine the transformer capacity and the scale of the power distribution system according to the electricity load calculation for tunnel construction. Usually, 10 kV or 35 kV high-voltage power supply is used for tunnel construction electricity, and it is reduced to 380 V / 220 V low-voltage power supply through a transformer. Second, set up a substation at or near the tunnel entrance and install equipment such as transformers, high- and low-voltage switch cabinets, and reactive power compensation devices. The substation should adopt rainproof, dustproof, and moisture-proof measures to ensure the safe operation of the equipment. Then, lay the main line cable along the tunnel. Usually, YJV-3×95+2×50mm 2 or YJV-3×120+2×70mm 2The armored cable is laid along one side wall of the tunnel, at a height of 2.5m - 3.0m from the ground, and fixed using a cable tray or cable clips. Then, a distribution box is set up every 100m - 150m, containing protection devices such as a circuit breaker and a leakage protector, providing power interfaces for various construction equipment. Finally, explosion-proof power sockets are installed at appropriate positions in the tunnel, with a spacing of no more than 50m, and the socket height is 0.8m - 1.0m above the ground. Each socket box is equipped with 3 - 5 sockets of different specifications to meet the power consumption needs of various construction equipment.

[0097] Certainly, in some alternative embodiments, for extra-long tunnel projects, the circuit system adopts the following configuration: a box-type substation with a capacity of 800kVA is set up at the tunnel entrance, containing a 10kV / 0.4kV dry-type transformer, high-voltage switchgear, low-voltage switchgear, and a reactive power compensation device. The main line uses YJV - 3×150 + 2×95mm 2 The armored cable is laid along the left side wall of the tunnel, at a height of 2.8m from the ground, and protected by a metal bridge. An explosion-proof distribution box is set up every 120m, with a specification of 800mm×600mm×250mm, containing a 100A main circuit breaker, 4 branch circuit breakers of 63A and 32A each, as well as protection devices such as a leakage protector and a current transformer. The power socket uses an explosion-proof combined socket box, set up every 40m. Each socket box is equipped with 2 sockets of three specifications: 380V / 63A, 380V / 32A, and 220V / 16A to meet the power consumption needs of different equipment. In addition, an emergency power supply is set up every 500m in the tunnel, using a UPS uninterruptible power supply system with a capacity of 20kVA, which can provide emergency power supply for the lighting system and key equipment for no less than 2 hours when the main power supply is interrupted.

[0098] By installing auxiliary tunneling equipment in the tunnel, it creates good working conditions for tunnel construction, with the following significant advantages:

[0099] First of all, the installation of the track system provides a convenient passage for the transportation of construction materials, equipment, and muck, greatly improving the material transportation efficiency, reducing labor consumption, and accelerating the construction progress. Compared with traditional tire vehicle transportation, track transportation has the characteristics of large load capacity, small resistance, and good stability, and is especially suitable for long-distance tunnel construction. According to engineering practice data, using track transportation can increase the transportation efficiency by 30% - 40% compared with tire vehicle transportation, and reduce energy consumption by 20% - 25%.

[0100] Secondly, the installation of the lighting system provides a good visual environment for tunnel construction, reducing construction errors and safety accidents caused by insufficient light. A reasonable lighting layout can make the average illuminance in the tunnel reach 100 - 150 lx, meeting the requirements of construction operations. Compared with traditional temporary lighting, the systematic lighting design has the advantages of uniform illuminance, high reliability, and low energy consumption. According to statistics, good lighting conditions can reduce the construction error rate by 15% - 20% and the incidence of safety accidents by 25% - 30%.

[0101] Thirdly, the installation of the walkway board provides a safe and convenient passage for construction workers, effectively separating the flow of people and logistics and reducing the risk of casualties. Especially in tunnels with track transportation, the setting of the walkway board enables personnel to maintain a safe distance from transportation equipment and avoid collision accidents. At the same time, the anti-slip treatment of the walkway board and the setting of guardrails further improve the safety of passage and reduce the occurrence of accidents such as slipping and falling.

[0102] Finally, the installation of the circuit system provides a stable and safe power supply for various construction equipment and is the energy guarantee for tunnel construction. Standardized circuit design and installation, equipped with perfect protection devices, effectively prevent electrical accidents such as electric shock, short circuit, and overload. At the same time, a reasonable power supply layout reduces temporary wiring and long-distance power supply, reduces line losses, and improves the power supply quality and reliability.

[0103] In one embodiment, after step S700, it further includes:

[0104] S800. Adjust the gauge of the track according to the preset transportation requirements.

[0105] Adjusting the gauge is a key operation to adapt to different types of transport vehicles and material transportation requirements, aiming to improve the applicability and operation efficiency of the transportation system.

[0106] Step S800 can ensure that the track still maintains good stability and load-bearing capacity under the adjusted gauge. First of all, a comprehensive analysis of the preset transportation requirements is needed, including specific information such as the size, weight, and running route of the transported materials, so as to determine the most suitable gauge range. Usually, the gauge of the track can be adjusted between 600 mm and 1200 mm to adapt to most construction scenarios.

[0107] Of course, the work of adjusting the gauge needs to be carried out on the premise of ensuring safety, which involves the re-layout of the track and the adjustment of the support structure. During the construction process, operators need to use professional equipment, such as gauge rulers, hydraulic support devices, etc., to accurately measure and adjust the gauge. During the adjustment process, the straightness and levelness of the track should be maintained to prevent the transport vehicle from skewing or derailing during operation. After the gauge is adjusted in place, a series of reinforcement measures are required, including adding support points, adjusting the ballast material, etc., to restore the original stability of the track.

[0108] By adjusting the gauge of the track according to the preset transportation requirements, it is possible to optimize the coordinated use of various resources on the basis of ensuring transportation safety and stability in response to different construction stages and task requirements, and show strong applicability in various engineering environments. At the same time, it supports the rapid switching of various styles and widths of transport vehicles, becoming an effective guarantee means for complex tunnel engineering construction.

[0109] In one embodiment, step S200 includes:

[0110] S210. Install steel pipe segments at the starting position and the receiving position of the tunnel according to the preset construction area.

[0111] Specifically, at the starting position, through detailed survey and measurement, the layout range and installation points of the steel pipe segments are determined. Before installation, the foundation treatment is first carried out, and the soil body can be compacted or grouted to meet the bearing and stability requirements. Subsequently, the steel pipe segments are hoisted to the designated positions in sequence, and the positions are adjusted through lifting equipment and guiding frames to make the arrangement of the steel pipe segments meet the design requirements. The steel pipe segments are fixed through prefabricated connection holes and bolts, and the spacing and angle are to ensure the formation of a continuous and stable support structure.

[0112] At the receiving position, the distribution and installation principle of the steel pipe segments is the same as that at the starting position, but special consideration needs to be given to the possible vibration and pressure fluctuation effects during the reception of the shield machine. The layout range of the steel pipe segments at the receiving position is usually wider than that at the starting position to cover the potentially unstable areas around the receiving area. At the same time, rubber cushions are added at the connection parts to reduce the irregular impact force generated during shield reception.

[0113] S220. Carry out welding operations on the steel pipe segments.

[0114] Specifically, the preferred welding methods are manual arc welding or carbon dioxide gas shielded welding. Before welding, the dirt and rust on the connection of the steel pipe segments should be cleaned to ensure that the welding surface is flat and clean; during welding, according to the designed thickness of the steel pipe segments, select the current range and welding speed. For example, for a 30-mm thick steel plate, an operation can be carried out with a current of 400A - 600A. During the welding operation process, arc interruption or burn-through phenomena should be avoided, otherwise it will affect the uniformity and strength of the weld seam. In addition, after welding is completed, weld quality inspection is required. For example, ultrasonic testing or visual inspection can be used to check whether there are defects such as pores and cracks in the weld seam.

[0115] S230. After completing the welding operation, install the shield machine at the starting position.

[0116] After completing the distribution installation and welding operation of the steel pipe segments, carry out the installation work of the shield machine. The shield machine is an important tunnel boring equipment, and its installation needs to be carried out on a stable construction platform to ensure the stable and efficient operation of the equipment.

[0117] Step S200 ensures the soil stability at the starting end and receiving end of the shield machine and the construction safety through the layout and segmented processing and welding of the steel pipe segments; through the precise installation and commissioning of the shield machine, it guarantees the efficient and stable operation of the tunneling equipment, and comprehensively improves the safety and construction efficiency of tunnel construction.

[0118] In one embodiment, step S220 includes:

[0119] Carry out the welding operation on the steel pipe segments by using a hierarchical welding method.

[0120] Specifically, in step S220, the steel pipe segments refer to important components for assembling the steel pipe support structure in the tunnel, and their welding methods directly affect the engineering quality and safety of tunnel construction. Through the hierarchical welding method, multiple welding formations can be achieved, thereby enhancing the weld seam strength, reducing stress concentration, and avoiding welding deformation.

[0121] In one embodiment, step S230 includes:

[0122] After completing the welding operation, process and detect the weld seam, and install the shield machine at the starting position.

[0123] Specifically, the weld seam refers to the metal bonding part formed by welding at the connection of the steel pipe segments, and its quality is directly related to the overall strength and stability of the tunnel support structure. The starting position refers to the starting point where the shield machine starts tunneling, usually located at the tunnel entrance, and it needs to have sufficient space and support strength to meet the requirements of shield machine installation and startup. The shield machine is the core equipment for tunnel construction, and its installation quality and accuracy directly affect the efficiency and safety of subsequent tunneling operations.

[0124] In one embodiment, after step S600, the method further includes:

[0125] S900. Conduct grouting operations on the portal of the connection tunnel.

[0126] Specifically, in step S900, the connection tunnel refers to a tunnel passage used to connect different areas or for escape within the tunnel, and its portal is the part of the entire passage structure that is most vulnerable to stress concentration and deformation. Therefore, conducting grouting operations on the portal is a key measure aimed at enhancing the structural stability and overall strength of the portal, preventing soil erosion and abnormal deformation.

[0127] In this embodiment, by implementing grouting operations on the portal of the connection tunnel in step S900, the stability and durability of the tunnel structure are significantly improved. It is applicable to tunnel projects with complex geological conditions and high requirements for structural stability. In practical applications, the method exemplified in this embodiment is simple to operate and easy to implement, with both high construction efficiency and excellent engineering quality, providing a reliable technical guarantee for the construction of various tunnel projects.

[0128] The above description is only an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformation made under the technical concept of the present invention by using the content of the specification and drawings of the present invention, or any direct / indirect application in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A shield construction method for a connection passage, characterized in that The method includes the following steps: Carry out end reinforcement operation on a preset construction area in the tunnel; wherein, the connecting passage is formed within the preset construction area; Install the portal steel segments and the shield machine of the connecting passage according to the preset construction area; Carry out portal grouting on the portal; Install a reference ring at the tail position of the shield machine; Weld anti-twist blocks on the outer periphery of the shield machine; After completing the temporary sealing of the portal, control the shield machine to carry out shield tunneling operation.

2. The shield tunneling method for the connection passage according to claim 1, characterized in that, The step of carrying out end reinforcement operation on a preset construction area in the tunnel includes: Adopt a triple-axis mixing pile to carry out end reinforcement operation on a preset construction area in the tunnel.

3. The shield tunneling method for the connection passage according to claim 2, characterized in that, Before the step of adopting a triple-axis mixing pile to carry out end reinforcement operation on a preset construction area in the tunnel, it further includes: Obtain the preset construction area according to preset construction data; wherein, the preset construction area is an area at least 3 meters outside the periphery of the connecting passage, 3 meters below the arch bottom and 4 meters above the arch top.

4. The shield tunneling method for connecting passage according to claim 3, wherein, The step of obtaining the preset construction area according to preset construction data includes: According to the preset construction data, strongly reinforce the area at least 3 meters outside the periphery of the connecting passage and 3 meters below the arch bottom, and weakly reinforce the area 4 meters above the arch top to obtain the preset construction area.

5. The shield tunneling method for the connection passage according to claim 1, wherein Before the step of installing the portal steel segments and the shield machine of the connecting passage according to the preset construction area, the method further includes: Install auxiliary tunneling equipment in the tunnel; wherein, the auxiliary tunneling equipment includes tracks, a lighting system, walkway boards and an electrical system.

6. The shield tunneling method for connecting passage according to claim 5, characterized in that, After the step of installing auxiliary tunneling equipment in the tunnel, it further includes: Adjust the gauge of the tracks according to the preset transportation requirements.

7. The shield tunneling method for the connection passage according to claim 1, characterized in that, The step of installing the portal steel segments and the shield machine of the connecting passage according to the preset construction area includes: Distributively install steel segments at the starting position and the receiving position of the tunnel according to the preset construction area; Carry out welding operation on the steel segments; After completing the welding operation, install the shield machine at the starting position.

8. The shield tunneling method for the connection passage according to claim 7, wherein, The step of carrying out welding operation on the steel segments includes: Adopt a hierarchical welding method to carry out welding operation on the steel segments.

9. The shield construction method for the connection passage according to claim 7, characterized in that, The step of installing the shield machine at the starting position after completing the welding operation includes: After completing the welding operation, process and detect the weld seams, and install the shield machine at the starting position.

10. The shield tunneling method for the connection passage according to claim 1, wherein, After the step of controlling the shield machine to carry out shield tunneling operation after completing the temporary sealing of the portal, the method further includes: Carry out grouting operation on the portal of the connecting passage.

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