Single-line variable cross-section tunnel contact line branching installation construction method

Abstract

The application provides a single-line variable cross-section tunnel contact network turnout installation construction method, and relates to the technical field of railway contact network construction. The application comprises the following steps: S1, construction preparation; S2, analysis of the characteristics of the supporting conductor at the variable cross-section of the tunnel; S3, analysis of turnout installation technology; S4, installation of a hanger column; S5, pre-arrangement installation of a cantilever arm; S6, erection of the supporting conductor and installation of contact suspension; S7, adjustment of the slope of the contact line; S8, adjustment of the parameter value of the turnout; and S9, re-measurement. The application has the advantages of rigorous installation process, small safety hazard, practicality, obvious economic effect, effective improvement of work efficiency and guarantee of engineering quality.

Description

Technical Field

[0001] This invention relates to the field of railway catenary construction technology, specifically a method for installing catenary turnouts in a single-track variable cross-section tunnel. Background Technology

[0002] With the steady and rapid development of the national economy and the continuous improvement of the railway transportation network, railways in remote areas will usher in a major development opportunity. With the planning and construction of single-track railways, large-span variable cross-section tunnels are constantly emerging. When the tunnel cross-section changes abruptly at the station exit, the tunnel cross-sectional dimensions change abruptly, from single-track to double-track, with the tunnel width increasing from 6 meters to 12 meters and the tunnel height increasing from 6.67 meters to 7.8 meters. This significantly increases the difficulty of the overhead contact line construction, especially at turnouts. The change in tunnel cross-sectional dimensions causes an upward slope in the contact wire, which greatly affects the adjustment of the turnout's initial contact area. Therefore, adopting effective technical measures to ensure the quality of turnout installation with variable cross-section contact wires in tunnels is crucial. Summary of the Invention

[0003] The purpose of this invention is to provide a method for installing contact wire turnouts in single-line variable cross-section tunnels, which makes the installation of contact wire turnouts at the variable cross-section of the tunnel scientific and accurate, thereby avoiding defects such as low quality of contact wire installation and great safety hazards.

[0004] To achieve the above objectives, the present invention provides a method for installing a single-line variable cross-section tunnel contact network turnout, comprising the following steps:

[0005] S1: Construction preparation: Familiarize yourself with the drawings, design requirements, and the specifications of various contact wire materials;

[0006] S2: Characteristics analysis of the conductor bearing at the variable cross-section of the tunnel: The interface dimensions at the variable cross-section tunnel are measured, and the slope value of the contact wire and the stress on the center of gravity of the conductor bearing are analyzed according to the contact wire acceptance specifications and technical standards.

[0007] S3: Turnout Installation Technical Analysis: Based on the parameter values ​​of turnout installation, the influence of the slope changes of the two conductor rails and the center of gravity stress on the turnout parameter values ​​is calculated.

[0008] S4: Installation of suspended columns: Pre-assembled in the factory and installed on site according to the changes in the height of the variable cross-section tunnel and the slope of the conductor rail.

[0009] S5: Pre-installation of cantilever arm: erection of conductor rails and installation and adjustment of contact suspension, arrangement of central anchor and temporary hanger, and temporary fixation of the variable cross-section clearance height;

[0010] S6: Erection of conductor and installation of contact suspension: Adjust the counterweight of the sinker according to the stress on the center of gravity of the conductor;

[0011] S7: Contact line slope adjustment;

[0012] S8: Adjustment of turnout parameter values;

[0013] S9: Retest: Conduct a comprehensive review of the overhead contact line conductor parameters to confirm whether the installation parameters are consistent with the design. If any non-compliance with technical standards is found, readjust the slope and turnout parameters.

[0014] Furthermore, in step S2, the formula for calculating the slope value of the conductor slope change is as follows:

[0015] S21: The variable cross-section section rises from H1 to H2 meters, while the distance from the catenary and the arched cantilever to the tunnel top remains basically unchanged. Therefore, the tunnel height change is basically consistent with that of the overhead contact line.

[0016] H = H1 - H2;

[0017] Sinα = H / L;

[0018] Wherein: H - maximum height adjustment value of the conductor rail, H1 - highest value of the tunnel, H2 - lowest value of the tunnel, α - rise slope value of the conductor rail, L - anchor section length;

[0019] S22: The length of the conductor is L1, the catenary is model JTMH-95 with a unit mass of F1, and the contact wire is model CTS120 with a unit mass of F2;

[0020] G1 = L1 × F1;

[0021] G2 = L1 × F2;

[0022] G3 = G1 + G2;

[0023] Wherein: G1 - total weight of catenary wire, G2 - total weight of contact wire, G3 - total weight of conductor wire;

[0024] S23: Both the main line and station line droppers adopt non-adjustable C-type integral current-carrying droppers. The integral dropper includes dropper wire, stamped catenary dropper wire clamp, heart-shaped guard ring, clamp tube, adjusting and fixing bolt, and crimp terminal; the unit weight of one dropper wire is F3, the average length of the dropper in the tunnel is about L2, so the weight of the dropper wire is G4 = F3 × L2, the total weight of the catenary clamp and the contact wire clamp is G5, so the total weight of one dropper wire clamp is G6 = G4 + G5;

[0025] An anchor section L1 has a dropper cable arranged on average every 5m.

[0026] N1 = L1 ÷ 5M / root;

[0027] G7 = N1 × G6;

[0028] Where: N1 - the total number of droppers for an anchor section, G7 - the total weight of droppers for an anchor section;

[0029] S24: The total number of anchor segments is: G = G3 + G4; where: G - total weight of anchor segments;

[0030] S25: Formula for calculating the force on the center of gravity of the conductor along the line: F=G*sinα; where: F-force on the conductor in the direction of the slope.

[0031] Furthermore, in step S4, the installation of the suspension column includes: measuring the clearance height of the variable cross-section tunnel and pre-installing the bow-shaped cantilever arm: when the clearance height of the tunnel is greater than 7200mm, the tunnel suspension column plus bow-shaped cantilever arm installation method is used for positioning, and the bow-shaped cantilever arm is adjusted by adjusting the base to keep it in a horizontal state, and the live parts maintain an insulation distance of at least 330mm from the tunnel wall; the suspension column plus cantilever arm installation method is used for intermediate columns and turnouts in large-span and multi-track tunnel sections.

[0032] Furthermore, in step S5, the pre-installation of the cantilever arm includes: measuring the height change △H of the tunnel cross-section, and calculating the installation height of the upper and lower cantilever arm bases for each span of the contact network as h0+△H / P, where h0 is the designed installation height; performing pre-installation of the cantilever arm according to the tunnel insulation distance requirements and pull-out value, installing the composite insulator and the bow-shaped cantilever arm or cantilever arm on the cantilever arm base at the corresponding position, and making adjustments; checking and re-measuring the insulation distance between the live part of each cantilever arm and the tunnel wall to ensure that the insulation gap is greater than the designed insulation distance.

[0033] Furthermore, in step S6, the installation of the conductor and the contact suspension includes: the conductor is anchored at the anchor point near the turnout in the tunnel, and a constant tension wire laying vehicle is used to install the conductor. The side contact wire is installed first, followed by the main contact wire. A central anchor and temporary hangers are arranged, and the variable cross-section clearance height is temporarily fixed. The catenary is guided into the catenary base, and the contact wire is installed and adjusted using positioning clamps. The weight of the weight is recalculated: based on the slope change of the clearance height at the tunnel variable cross-section, the force F on the conductor along the line is calculated. According to the design pulley block configuration, the weight of the weight is reduced accordingly when anchoring at low clearance, while the design weight M is still used at high clearance, where M is the design rated weight.

[0034] Furthermore, in step S7, the contact line slope adjustment includes: first, measuring the slope of the main line according to the contact line rise slope P value, and the value of the front-to-back height difference / span ≤ P value is qualified; second, adjusting the slope of the side contact line, and the value of the front-to-back height difference / span ≤ P value is qualified. The guide height is strictly adjusted according to the direction of the working support and non-working support contact lines, and its rise slope value should meet the design requirements and not form a negative slope.

[0035] Furthermore, in step S8, the adjustment of the turnout parameter values ​​includes:

[0036] S81: Re-inspect and fine-tune the cantilever arm and catenary: Using a multi-functional laser detector and other catenary measuring instruments, adjust the bow-shaped cantilever arm or cantilever arm offset along the track in the turnout section to be in place, making it perpendicular to the track. The allowable construction deviation shall not exceed +20mm. Tighten the catenary seat bolts with a torque wrench, adjust the pull-out value of the turnout positioning column and the two front and rear supports, check the distance between the working support and the non-working support catenary, the distance shall not be less than 50mm, and the distance between the intersection points of the two catenary cables at the cross turnout shall not be less than 20mm. If the gap is too small or there is friction, it should be adjusted to separate them.

[0037] S82: Re-inspection and fine-tuning of conductor height and pull-out value: After moving the positioning point, the ground workers use a laser measuring instrument to check whether the conductor height and pull-out value of the two conductors of the positioning column meet the design requirements, and use the work vehicle to fine-tune them to meet the standards; because the conductor is in the overall slope or overall slope area, it will affect the adjustment accuracy of the initial contact area, so the conductor height and pull-out value of the main line are adjusted, and then the pull-out value of the crossover line is adjusted. The crossover line elevation is first adjusted to the correct position with a temporary dropper, and then the formal dropper is pre-installed according to the actual length, and the branch pipe is installed;

[0038] S83: Check the initial contact area and fine-tune the cross suspension wires: Use a laser measuring instrument to check whether the initial contact area meets the design requirements and adjust it to meet the standards; finally, remove the 4 temporary fixing points of the support column and re-measure; remove unsuitable suspension wires first, temporarily adjust them with φ2.0 iron wire, and measure the length of the suspension wires for prefabrication and replacement.

[0039] Furthermore, in step S9, the retest includes: after the turnout positioning, installation, and adjustment are completed, checking the turnout pull-out value, contact wire height difference, and initial contact area parameter values ​​in the variable cross-section tunnel section; retesting whether the slope of the contact wires of the main line and side line meets the design requirements; and after the installation and adjustment are completed, using a cold sliding car to check the pantograph dynamic envelope of the contact network, simulating the pantograph detection positioning device and the turnout area contact suspension; simulating the train sliding twice along the main line and side line in the positive direction within the turnout area, and when passing the main line, the pantograph should not contact the side line contact wire, and the transition into and out of the side line should be smooth, without any pantograph drilling or hard points.

[0040] Compared with the prior art, the beneficial effects of the present invention are:

[0041] The construction method of the present invention significantly improves economic efficiency and construction efficiency, effectively enhances work efficiency, and ensures project quality. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the method steps of the present invention. Detailed Implementation

[0043] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0044] like Figure 1 As shown, a method for installing a single-track variable cross-section tunnel contact network turnout includes the following steps:

[0045] S1: Construction preparation: Familiarize yourself with the drawings, design requirements, and the specifications of various contact wire materials;

[0046] S2: Characteristics analysis of the conductor bearing at the variable cross-section of the tunnel: The interface dimensions at the variable cross-section tunnel are measured, and the slope value of the contact wire and the stress on the center of gravity of the conductor bearing are analyzed according to the contact wire acceptance specifications and technical standards.

[0047] S3: Turnout Installation Technical Analysis: Based on the parameter values ​​of turnout installation, the influence of the slope changes of the two conductor rails and the center of gravity stress on the turnout parameter values ​​is calculated.

[0048] S4: Installation of suspended columns: Pre-assembled in the factory and installed on site according to the changes in the height of the variable cross-section tunnel and the slope of the conductor rail.

[0049] S5: Pre-installation of cantilever arm: erection of conductor rails and installation and adjustment of contact suspension, arrangement of central anchor and temporary hanger, and temporary fixation of the variable cross-section clearance height;

[0050] S6: Erection of conductor and installation of contact suspension: Adjust the counterweight of the sinker according to the stress on the center of gravity of the conductor;

[0051] S7: Contact line slope adjustment;

[0052] S8: Adjustment of turnout parameter values;

[0053] S9: Retest: Conduct a comprehensive review of the overhead contact line conductor parameters to confirm whether the installation parameters are consistent with the design. If any non-compliance with technical standards is found, readjust the slope and turnout parameters.

[0054] In step S2, the formula for calculating the slope value of the conductor rail is as follows:

[0055] S21: The variable cross-section section rises from H1 to H2 meters, while the distance from the catenary and the arched cantilever to the tunnel top remains basically unchanged. Therefore, the tunnel height change is basically consistent with that of the overhead contact line.

[0056] H = H1 - H2;

[0057] Sinα = H / L;

[0058] Wherein: H - maximum height adjustment value of the conductor rail, H1 - highest value of the tunnel, H2 - lowest value of the tunnel, α - rise slope value of the conductor rail, L - anchor section length;

[0059] S22: The length of the conductor is L1, the catenary is model JTMH-95 with a unit mass of F1, and the contact wire is model CTS120 with a unit mass of F2;

[0060] G1 = L1 × F1;

[0061] G2 = L1 × F2;

[0062] G3 = G1 + G2;

[0063] Wherein: G1 - total weight of catenary wire, G2 - total weight of contact wire, G3 - total weight of conductor wire;

[0064] S23: Both the main line and station line droppers adopt non-adjustable C-type integral current-carrying droppers. The integral dropper includes dropper wire, stamped catenary dropper wire clamp, heart-shaped guard ring, clamp tube, adjusting and fixing bolt, and crimp terminal; the unit weight of one dropper wire is F3, the average length of the dropper in the tunnel is about L2, so the weight of the dropper wire is G4 = F3 × L2, the total weight of the catenary clamp and the contact wire clamp is G5, so the total weight of one dropper wire clamp is G6 = G4 + G5;

[0065] An anchor section L1 has a dropper cable arranged on average every 5m.

[0066] N1 = L1 ÷ 5M / root;

[0067] G7 = N1 × G6;

[0068] Where: N1 - the total number of droppers for an anchor section, G7 - the total weight of droppers for an anchor section;

[0069] S24: The total number of anchor segments is: G = G3 + G4; where: G - total weight of anchor segments;

[0070] S25: Formula for calculating the force on the center of gravity of the conductor along the line: F=G*sinα; where: F-force on the conductor in the direction of the slope.

[0071] In step S4, the installation of the suspension column includes: measuring the clearance height of the variable cross-section tunnel and pre-installing the bow-shaped cantilever arm: when the clearance height of the tunnel is greater than 7200mm, the tunnel suspension column plus bow-shaped cantilever arm installation method is used for positioning, and the bow-shaped cantilever arm is adjusted by adjusting the base to keep it in a horizontal state, and the live parts are kept at least 330mm away from the tunnel wall; the suspension column plus cantilever arm installation method is used for intermediate columns and turnouts in large-span and multi-track tunnel sections.

[0072] In step S5, the pre-installation of the cantilever arm includes: measuring the height change △H of the tunnel cross-section, and calculating the installation height of the upper and lower cantilever arm bases for each span of the contact network as h0+△H / P, where h0 is the designed installation height; performing pre-installation of the cantilever arm according to the tunnel insulation distance requirements and pull-out value, installing the composite insulator and the bow-shaped cantilever arm or cantilever arm on the cantilever arm base at the corresponding position, and making adjustments; checking and re-measuring the insulation distance between the live part of each cantilever arm and the tunnel wall to ensure that the insulation gap is greater than the designed insulation distance.

[0073] In step S6, the conductor erection and contact suspension installation include: the conductor is anchored at the turnout location in the tunnel, and a constant tension wire laying vehicle is used for conductor erection. First, the side contact wire is erected, then the main contact wire is erected, and a central anchor and temporary hanger are arranged. The variable cross-section clearance height is temporarily fixed, and the catenary is guided into the catenary base. The contact wire is installed and adjusted using positioning clamps. The counterweight weight is recalculated: based on the slope change of the clearance height at the tunnel variable cross-section, the force F on the conductor along the line is calculated. According to the design pulley block configuration, the weight of the anchor weight is reduced accordingly at low clearance locations, while the design counterweight weight M is still used at high clearance locations, where M is the design rated counterweight weight.

[0074] In step S7, the contact line slope adjustment includes: first, measuring the slope of the main line according to the contact line rise slope P value, and the value of the front-to-back height difference / span ≤ P value is qualified; second, adjusting the slope of the side contact line, and the value of the front-to-back height difference / span ≤ P value is qualified. The guide height is strictly adjusted according to the direction of the working support and non-working support contact lines, and its rise slope value should meet the design requirements and not form a negative slope.

[0075] In step S8, the adjustment of the turnout parameter values ​​includes:

[0076] S81: Re-inspect and fine-tune the cantilever arm and catenary: Using a multi-functional laser detector and other catenary measuring instruments, adjust the bow-shaped cantilever arm or cantilever arm offset along the track in the turnout section to be in place, making it perpendicular to the track. The allowable construction deviation shall not exceed +20mm. Tighten the catenary seat bolts with a torque wrench, adjust the pull-out value of the turnout positioning column and the two front and rear supports, check the distance between the working support and the non-working support catenary, the distance shall not be less than 50mm, and the distance between the intersection points of the two catenary cables at the cross turnout shall not be less than 20mm. If the gap is too small or there is friction, it should be adjusted to separate them.

[0077] S82: Re-inspection and fine-tuning of conductor height and pull-out value: After moving the positioning point, the ground workers use a laser measuring instrument to check whether the conductor height and pull-out value of the two conductors of the positioning column meet the design requirements, and use the work vehicle to fine-tune them to meet the standards; because the conductor is in the overall slope or overall slope area, it will affect the adjustment accuracy of the initial contact area, so the conductor height and pull-out value of the main line are adjusted, and then the pull-out value of the crossover line is adjusted. The crossover line elevation is first adjusted to the correct position with a temporary dropper, and then the formal dropper is pre-installed according to the actual length, and the branch pipe is installed;

[0078] S83: Check the initial contact area and fine-tune the cross suspension wires: Use a laser measuring instrument to check whether the initial contact area meets the design requirements and adjust it to meet the standards; finally, remove the 4 temporary fixing points of the support column and re-measure; remove unsuitable suspension wires first, temporarily adjust them with φ2.0 iron wire, and measure the length of the suspension wires for prefabrication and replacement.

[0079] In step S9, the retest includes: after the turnout positioning, installation and adjustment are completed, checking the turnout pull-out value, contact wire height difference and initial contact area parameter value of the variable cross-section tunnel section turnout, and retesting whether the slope of the contact wire of the main line and the side line meets the design requirements; and after the installation and adjustment are completed, using a cold sliding car to check the pantograph dynamic envelope of the contact network, simulating the pantograph detection positioning device and the turnout area contact suspension; simulating the train sliding twice along the main line and the side line in the positive direction within the turnout area, when the main line passes, the pantograph should not contact the side line contact wire, and the transition into and out of the side line should be smooth, without any pantograph drilling or hard points.

[0080] Based on the statistics of on-site construction completion and personnel input, the construction method of this invention is compared with the traditional construction method:

[0081] Using traditional construction methods, 12 people per group can complete one site in two days, requiring 24 working days.

[0082] Using the construction method of this invention, 12 people per group can complete one site in one day, requiring 12 working days.

[0083] Using this construction method can save approximately 8*24-8*12=96 in labor costs, reducing labor costs by 96 working days per construction site. Therefore, the construction method of this invention significantly improves economic efficiency and construction efficiency, effectively increasing work efficiency and ensuring project quality.

[0084] The various embodiments of the present invention have been described above. The above description is exemplary and not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for installing a single-track variable cross-section tunnel contact network turnout, characterized in that, Includes the following steps: S1: Construction preparation: Familiarize yourself with the drawings, design requirements, and the specifications of various contact wire materials; S2: Characteristics analysis of the conductor bearing at the variable cross-section of the tunnel: The interface dimensions at the variable cross-section tunnel are measured, and the slope value of the contact wire and the stress on the center of gravity of the conductor bearing are analyzed according to the contact wire acceptance specifications and technical standards. In step S2, the formula for calculating the slope value of the conductor rail is as follows: S21: The variable cross-section section rises from H1 to H2 meters, while the distance from the catenary and the arched cantilever to the tunnel top remains basically unchanged. Therefore, the tunnel height change is basically consistent with that of the overhead contact line. H = H1 - H2; Sinα = H / L; Wherein: H - maximum height adjustment value of the conductor rail, H1 - highest value of the tunnel, H2 - lowest value of the tunnel, α - rise slope value of the conductor rail, L - anchor section length; S22: The length of the conductor is L1, the catenary is model JTMH-95 with a unit mass of F1, and the contact wire is model CTS120 with a unit mass of F2; G1 = L1 × F1; G2 = L1 × F2; G3 = G1 + G2; Wherein: G1 - total weight of catenary wire, G2 - total weight of contact wire, G3 - total weight of conductor wire; S23: Both the main line and station line droppers adopt non-adjustable C-type integral current-carrying droppers. The integral dropper includes dropper wire, stamped catenary dropper wire clamp, heart-shaped guard ring, clamp tube, adjusting and fixing bolt, and crimp terminal; the unit weight of one dropper wire is F3, the average length of the dropper in the tunnel is about L2, so the weight of the dropper wire is G4=F3×L2, the total weight of the catenary clamp and the contact wire clamp is G5, so the total weight of one dropper wire clamp is G6=G4+G5; An anchor section L1 has a dropper cable arranged on average every 5m. N1 = L1 ÷ 5M / root; G7 = N1 × G6; Where: N1 - the total number of droppers for an anchor section, G7 - the total weight of droppers for an anchor section; S24: The total number of anchor segments is: G = G3 + G4; where: G - total weight of anchor segments; S25: Formula for calculating the force on the center of gravity of a conductor along the line: F=G sinα; where: F - the force acting on the conductor in the direction of the slope; S3: Turnout Installation Technical Analysis: Based on the parameter values ​​of turnout installation, the influence of the slope changes of the two conductor rails and the center of gravity stress on the turnout parameter values ​​is calculated. S4: Installation of suspended columns: Pre-assembled in the factory and installed on site according to the changes in the height of the variable cross-section tunnel and the slope of the conductor rail. S5: Pre-installation of cantilever arm: erection of conductor rails and installation and adjustment of contact suspension, arrangement of central anchor and temporary hanger, and temporary fixation of the variable cross-section clearance height; S6: Erection of conductor and installation of contact suspension: Adjust the counterweight of the sinker according to the stress on the center of gravity of the conductor; S7: Contact line slope adjustment; S8: Adjustment of turnout parameter values; S9: Retest: Conduct a comprehensive review of the overhead contact line conductor parameters to confirm whether the installation parameters are consistent with the design. If any non-compliance with technical standards is found, the slope and turnout parameters should be readjusted.

2. The method for installing a single-line variable cross-section tunnel contact network turnout according to claim 1, characterized in that, In step S4, the installation of the suspension column includes: measuring the clearance height of the variable cross-section tunnel and pre-installing the bow-shaped cantilever arm: when the clearance height of the tunnel is greater than 7200mm, the tunnel suspension column plus bow-shaped cantilever arm installation method is used for positioning, and the bow-shaped cantilever arm is adjusted by adjusting the base to keep it in a horizontal state, and the live parts are kept at least 330mm away from the tunnel wall; the suspension column plus cantilever arm installation method is used for intermediate columns and turnouts in large-span and multi-track tunnel sections.

3. The method for installing a single-line variable cross-section tunnel contact network turnout according to claim 1, characterized in that, In step S5, the pre-installation of the cantilever arm includes: measuring the height change △H of the tunnel cross-section, and calculating the installation height of the upper and lower cantilever arm bases for each span of the contact network as h0+△H / P, where h0 is the designed installation height; performing pre-installation of the cantilever arm according to the tunnel insulation distance requirements and pull-out value, installing the composite insulator and the bow-shaped cantilever arm or cantilever arm on the cantilever arm base at the corresponding position, and making adjustments; checking and re-measuring the insulation distance between the live part of each cantilever arm and the tunnel wall to ensure that the insulation gap is greater than the designed insulation distance.

4. The method for installing a single-line variable cross-section tunnel contact network turnout according to claim 1, characterized in that, In step S6, the conductor erection and contact suspension installation include: the conductor is anchored at the turnout location in the tunnel, and a constant tension wire laying vehicle is used for conductor erection. First, the side contact wire is erected, then the main contact wire is erected, and a central anchor and temporary hanger are arranged. The variable cross-section clearance height is temporarily fixed, and the catenary is guided into the catenary base. The contact wire is installed and adjusted using positioning clamps. The counterweight weight is recalculated: based on the slope change of the clearance height at the tunnel variable cross-section, the force F on the conductor along the line is calculated. According to the design pulley block configuration, the weight of the anchor weight is reduced accordingly at low clearance locations, while the design counterweight weight M is still used at high clearance locations, where M is the design rated counterweight weight.

5. The method for installing a single-line variable cross-section tunnel contact network turnout according to claim 1, characterized in that, In step S7, the contact line slope adjustment includes: first, measuring the slope of the main line according to the contact line rise slope P value, and the value of the front-to-back height difference / span ≤ P value is qualified; second, adjusting the slope of the side contact line, and the value of the front-to-back height difference / span ≤ P value is qualified. The guide height is strictly adjusted according to the direction of the working support and non-working support contact lines, and its rise slope value should meet the design requirements and not form a negative slope.

6. The method for installing a single-line variable cross-section tunnel contact network turnout according to claim 1, characterized in that, In step S8, the adjustment of the turnout parameter values ​​includes: S81: Re-inspect and fine-tune the cantilever arm and catenary: Using a multi-functional laser detector and other catenary measuring instruments, adjust the bow-shaped cantilever arm or cantilever arm offset along the track in the turnout section to be in place, making it perpendicular to the track. The allowable construction deviation shall not exceed +20mm. Tighten the catenary seat bolts with a torque wrench, adjust the pull-out value of the turnout positioning column and the two front and rear supports, check the distance between the working support and the non-working support catenary, the distance shall not be less than 50mm, and the distance between the intersection points of the two catenary cables at the cross turnout shall not be less than 20mm. If the gap is too small or there is friction, it should be adjusted to separate them. S82: Re-inspection and fine-tuning of conductor height and pull-out value: After moving the positioning point, the ground workers use a laser measuring instrument to check whether the conductor height and pull-out value of the two conductors of the positioning column meet the design requirements, and use the work vehicle to fine-tune them to meet the standards; because the conductor is in the overall slope or overall slope area, it will affect the adjustment accuracy of the initial contact area, so the conductor height and pull-out value of the main line are adjusted, and then the pull-out value of the crossover line is adjusted. The crossover line elevation is first adjusted to the correct position with a temporary dropper, and then the formal dropper is pre-installed according to the actual length, and the branch pipe is installed; S83: Check the initial contact area and fine-tune the cross suspension wires: Use a laser measuring instrument to check whether the initial contact area meets the design requirements and adjust it to meet the standards; finally, remove the 4 temporary fixing points of the support column and re-measure; remove unsuitable suspension wires first, temporarily adjust them with φ2.0 iron wire, and measure the length of the suspension wires for prefabrication and replacement.

7. The method for installing a single-line variable cross-section tunnel contact network turnout according to claim 1, characterized in that, In step S9, the retest includes: after the turnout positioning, installation and adjustment are completed, checking the turnout pull-out value, contact wire height difference and initial contact area parameter value of the variable cross-section tunnel section turnout, and retesting whether the slope of the contact wire of the main line and the side line meets the design requirements; and after the installation and adjustment are completed, using a cold sliding car to check the pantograph dynamic envelope of the contact network, simulating the pantograph detection positioning device and the turnout area contact suspension; simulating the train sliding twice along the main line and the side line in the positive direction within the turnout area, when the main line passes, the pantograph should not contact the side line contact wire, and the transition into and out of the side line should be smooth, without any pantograph drilling or hard points.

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