Ballastless track upward-arching cutting track-falling treatment method in tunnel

Abstract

The invention discloses a ballastless track upward-arching cutting track-falling treatment method in a tunnel. According to the method, supporting blocks are adopted below all sleepers for supporting, so that the safety is high; a rope saw is adopted for horizontal and vertical cutting, so that the inverted arch filling layer of the to-be-cut part of the renovation section forms a completely independent construction unit, and the work efficiency is improved; and the ballast bed of the renovation section is finely adjusted, CP III retesting is carried out at the same time, and concrete not lower than C30 is adopted to restore the cushion layer to the original design condition, so that the construction quality is guaranteed.

Description

Technical Field

[0001] The invention relates to a regulation method, in particular to a regulation method for cutting and falling ballastless tracks in tunnels. Background Art

[0002] Ballastless track has the advantages of high stability, less maintenance and long service life, and is the main track structure used in high-speed railways. However, due to unfavorable factors such as construction quality, deformation of the lower foundation, and water seepage in the tunnel, the ballastless track in some tunnels has suffered from track slab arching disease, which seriously affects the safety of train travel.

[0003] In order to solve the problem of arching disease, the existing technology often adopts the following methods: Track slab overall cutting and adjustment method, this method uses a rope saw to cut the track slab horizontally to release internal stress; uses a hydraulic jacking device to lift the track slab to the designed elevation; and injects high-strength polymer mortar to fill the cut seam and solidify it. However, this method has the following defects: low efficiency: a single cut takes 6 to 8 hours, affecting the skylight operation time; structural damage risk: improper cutting depth control can easily lead to track slab fracture; high material cost.

[0004] The micro-disturbance grouting lifting method, in which holes are drilled under the track slab and grouting pipes are implanted; low-viscosity epoxy resin slurry (viscosity ≤ 100cP) is injected in stages; the lifting amount is controlled by a pressure sensor (accuracy 0.1mm). However, this method has the following defects: limited scope of application: only applicable to slight arching with a settlement of ≤ 10mm; poor long-term stability: epoxy resin is prone to aging under dynamic loads, and the lifting rebound rate is ≥ 15% after 5 years; strong equipment dependence: special grouting equipment is required, and transportation in mountain tunnels is difficult.

[0005] Prestressed anchor reinforcement method: This method implants prestressed anchors (32mm in diameter and 8m in length) on both sides of the track slab; applies a 100kN preload to lock the track slab; and fills the anchor area with expansive concrete. However, this method has the following defects: large construction interference: drilling vibration causes local loosening of the track bed, requiring additional reinforcement; insufficient durability: the interface between the anchor and concrete is prone to electrochemical corrosion in a hot and humid environment; landscape damage: the exposed anchor head affects the clearance in the tunnel, requiring secondary treatment. Summary of the invention

[0006] In order to solve the defects in the prior art, the present invention discloses a method for regulating the upper arch cutting and falling track of ballastless track in a tunnel, and the technical scheme thereof is as follows: The method for treating the ballastless track in a tunnel by cutting and falling the arch comprises the following steps: 1) Use a total station to measure the line shape, collect track basic data, investigate the thickness of the pad, and determine the range and amount of track drop; 2) Adjust the data according to the renovation length, working time during the window period and the geometric state of the track bed slab. In principle, divide the length into 1 unit of 1.5 to 2 meters and mark the cutting position; 3) Connecting steel bars are implanted along the longitudinal direction of the line from the track slab to the backfill layer of the invert arch at both ends outside the renovated section to strengthen the connection between the filling layer and the track slab and ensure integrity; 4) Chisel away the cushion concrete on both sides of the ballast slab and the backfill concrete between the tracks to form a construction groove; 5) Drill holes on both sides of the remediation unit according to the unit division of the invert backfill layer; the rope saw cutting hole is perpendicular to the rail, and the top of the drill hole is located at the interface between the ballast plate and the filling layer; 6) During the operation, within the regulation section, a limit device is set on both sides of the track bed every 3m along the longitudinal direction of the line. The limit device can be adjusted appropriately according to the tooling configuration of the construction unit; 7) The rope saw performs vertical cutting in the two construction holes at the ends of the renovation section, and separates the roadbed slab in the renovation section into independent units according to the renovation scope; 8) Use a rope saw to first cut 50 mm vertically downward in the borehole and then cut horizontally, so that the invert filling layer of the section to be cut forms a completely independent construction unit; 9) Push out the cut concrete laterally and use support blocks under each sleeper. The size of the support blocks can be adjusted according to the actual cutting thickness. Rubber gaskets of the same size are set on the top of the support blocks. 10) After all the cutting is completed and the ballast bed is in a stable state, re-measure the geometric state of the ballast bed, determine the final amount of ballast bed plate falling, and do a good job of support and limit; 11) Clean the concrete at the cutting joint, set up the formwork after cleaning, and set up inspection holes on the ballast plate; 12) Steel bars are used to anchor the ballast plate and the tunnel invert in the renovated section; the spacing of the anchor bars is 2 bars per sleeper; after the holes are drilled, adhesive is injected into the holes, and finally high-strength grouting material is used to seal and smooth them; 13) Fine-tune the roadbed in the renovated section and conduct CPⅢ retest at the same time; 14) Use concrete of grade no lower than C30 to restore the cushion layer to the original design condition; 15) Partially chisel away the concrete of the ballast slabs on the top and sides of the emergency remediation area and the adjacent ballast slab ends; then clean the slag and rust on the surface of the steel bars, weld stainless steel grounding terminals on them, and repair the ballast slabs with resin mortar. Finally, connect the adjacent grounding terminals to the grounding steel cables to restore the integrated grounding system in the ballast slabs.

[0007] The invention also discloses a system for regulating the upper arch cutting and falling track of ballastless track in a tunnel, which is characterized in that the system comprises the above-mentioned method for regulating the upper arch cutting and falling track of ballastless track in a tunnel to regulate the upper arch cutting and falling track of ballastless track in a tunnel. Beneficial Effects

[0008] Support blocks are used under each sleeper to ensure safety. Wire saws are used for horizontal and vertical cutting, so that the arch filling layer to be cut in the renovation section forms a completely independent construction unit, which improves work efficiency. The roadbed in the renovation section is fine-tuned, and CPⅢ re-survey is carried out at the same time. Concrete of no less than C30 is used to restore the cushion layer to the original design to ensure construction quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 Schematic diagram of anchoring reinforcement in non-remediation sections; Figure 2 Schematic diagram of the scope of trench removal during rope saw construction; Figure 3 Schematic diagram of track bed plate limit; Figure 4 Schematic diagram of the cutting position of the track bed plate; Figure 5 Schematic diagram of the placement of the ballast plate support block; Figure 6 Arrangement diagram of reinforcing bars after landing; Figure 7 The area where the integrated grounding slab is chiseled out (the grounding terminal is within the scope of the renovation); Figure 8 Schematic diagram of the connection between the grounding terminal and the integrated grounding reinforcement; Fig. 9 Schematic diagram of the grounding terminal setting position. DETAILED DESCRIPTION

[0010] The present invention discloses that after the tunnel invert is stable, it is suggested to adopt the scheme of cutting the invert backfill layer with a rope saw to thoroughly regulate the track, including the following contents: (1) A transportation organization plan with limited speed driving is adopted. It is recommended that the speed limit during construction be 45 km / h. Construction should be carried out within the skylight point. The roadbed slab and the concrete backfill layer of the invert should be cut and separated by a rope saw, and the roadbed slab should be lowered to the track. After the roadbed slab is lowered to the track, grouting material should be used to restore the track structure.

[0011] (2) The main steps and technical requirements are as follows: 1) Use a total station to measure the line shape, collect track basic data, investigate the thickness of the pad, and determine the range and amount of track drop.

[0012] 2) Adjust the data according to the renovation length, working time during the window period and the geometric state of the track bed slab. In principle, divide it into one unit with a length of 1.5 to 2 meters and mark the cutting position.

[0013] 3) Plant 10 rows of connecting steel bars along the longitudinal direction of the line from the track plate to the backfill layer of the arch at both ends outside the renovated section to strengthen the combination of the filling layer and the track plate to ensure integrity. The spacing between the anchoring steel bars is about 1.3m (two steel bars are set for every sleeper), the drilling diameter is 22mm~32mm, and the drilling depth is 0.5m~0.8m. After the holes are drilled, use an air gun to blow away the dust and inject the steel bar embedding glue into the hole. The embedded steel bars use HRB500Ф20~Ф25 threaded steel bars with a length of not less than 0.5m. The steel bars must be inserted to the bottom of the hole, and finally sealed and smoothed with high-strength grouting material. The embedded steel bar arrangement is shown in the figure below: Main technical requirements for anchor glue: ① The rebar embedding materials and embedding process shall meet the relevant provisions of the Technical Specification for Post-Anchorage of Concrete Structures (JGJ 145-2004), the Design Code for Reinforcement of Concrete Structures (GB 50367-2006), and the Acceptance Code for Construction Quality of Building Structure Reinforcement Engineering (GB50550-2010). The rebar embedding glue shall be Class A glue and shall meet the requirements of Class A glue of the Chinese national standard GB50367 and the various requirements for rebar embedding glue in the acceptance standard of GB50550.

[0014] 4) Chisel away the cushion concrete on both sides of the trackbed slab, with the chiseling range being 20cm~30cm deep and 60cm~80cm wide.

[0015] The backfill layer of concrete between the lines is chiseled off to form a construction groove to facilitate the installation of cutting seam drilling equipment, rope saw guide wheel, jack, internal fine-adjustment device and limit device.

[0016] 5) Drill holes on both sides of the remediation unit according to the unit division of the invert backfill layer. The wire saw cuts the hole perpendicular to the rail, the top of the hole is located at the interface between the ballast plate and the filling layer, the diameter of the hole is 50mm~108mm, and it is drilled horizontally.

[0017] 6) During the operation, within the treatment section, a limit device is set on both sides of the ballast plate at intervals of approximately 1.5m~3m along the longitudinal direction of the line, as shown in the figure below. The limit device can be appropriately adjusted according to the tooling configuration, but the limit should be fixed firmly and reliably to ensure the stability of the ballast structure during the entire disease treatment construction period.

[0018] 7) The rope saw performs vertical cutting in the two construction holes at the ends of the renovation section, separating the ballast slab in the renovation section into independent units according to the renovation range, with a cutting thickness of 30mm. The rails above the ballast slab at the cutting position are protected by a wooden "U"-shaped protective device.

[0019] 8) Use a rope saw to first cut vertically downward 50mm in the drill hole and then cut horizontally, so that the arch filling layer to be cut in the renovation section forms a completely independent construction unit with a cutting thickness of 150mm.

[0020] After horizontal cutting, the roadbed plate is supported by steel pads to ensure driving requirements. Before the skylight is completed, 1~10mm thick steel plates are used for combined support in the cutting gap, with a size of 150mm×150mm and a support spacing of 0.65m (the steel plate support is directly below the sleeper), which can be adjusted according to the actual cutting thickness and removed before the next skylight operation.

[0021] 9) Push the cut concrete out horizontally and use support blocks under each sleeper. The support block size is 300mm×140mm, the height is 150mm, and the support block spacing is 0.65m (the support block is set directly under the sleeper). It can be adjusted according to the actual cutting thickness. A rubber gasket of the same size is set on the top of the support block.

[0022] 10) After all the cutting is completed and the ballast bed is stable, re-measure the geometric state of the ballast bed to determine the final amount of ballast bed slabs to be dropped, and do a good job of support and limit. Jacks are arranged on both sides of the ballast bed slab every 3m along the longitudinal direction of the line. The ballast bed slab is supported by the jacks, and the support pads under the ballast bed slab are taken out, and the jacks are adjusted to drop. During the drop process, the track elevation and plane should be monitored in real time. After the drop, concrete pads with a strength grade not less than C30 are used for support. The size of the concrete blocks is 300mm×240mm, and the thickness is determined according to the drop amount.

[0023] If the elevation of the local ballast plate deviates greatly from the design value, the elevation can be adjusted by fine-tuning the height of the internal limit device. After the ballast plate is put on the track, tighten the limit device screws on both sides of the ballast plate, and use a total station and a level to re-measure the geometric state of the adjusted ballast plate. If there is a slight deviation in the lateral direction of the ballast plate, it can be adjusted through the lateral screws of the limit device.

[0024] 11) Clean the concrete at the cutting joint. After cleaning, set up the formwork (the formwork is about 100mm away from the edge of the roadbed slab), and set up inspection holes (vent holes) on the roadbed slab with a diameter of 50mm, located on the center line of the roadbed slab, and set one every 2.6m. The grouting should ensure that the bottom of the slab is dense, and the grouting surface is not less than 10mm higher than the bottom of the roadbed slab (observe both sides of the roadbed slab and in the inspection hole at the same time).

[0025] 12) Ø20 steel bars are used to anchor the roadbed slab and the tunnel invert in the renovated section. The spacing between the anchoring steel bars is about 1.3m (two steel bars are set for every sleeper), the drilling diameter is 22mm~32mm, and the drilling depth is 0.5m~0.8m. After the hole is drilled, the dust is blown away with an air gun, and the steel bar glue is injected into the hole. The steel bars are HRB500Ф20~Ф25 threaded steel bars with a length of not less than 0.5m. The steel bars must be inserted to the bottom of the hole, and finally sealed and smoothed with high-strength grouting material. The steel bar arrangement is shown in the figure below: 13) Fine-tune the roadbed in the renovated section and carry out CPⅢ re-survey.

[0026] 14) Use concrete of grade no less than C30 to restore the cushion layer to its original design condition.

[0027] 15) Repair of the integrated grounding system. For example, the original design of the Huama Tunnel used a continuous ballast plate, and the structural steel bars were used to construct an integrated grounding system. The ballast plate grounding formed a grounding unit every 100m, and the middle of the grounding unit was reliably connected to the through-ground wire in a single "T" shape. For this emergency treatment of the disease, it is necessary to cut off both ends of the ballast plate within the remediation range, which will destroy the established integrated grounding system. Therefore, the integrated grounding system needs to be restored in time after the construction is completed. The restoration method is as follows.

[0028] The concrete of the ballast slab shall be partially chiseled off in the emergency remediation area and the top of the sides of the adjacent ballast slab ends. The chiseling area shall not be less than 150mm×90mm×60mm (length×width×height), and ensure that all the connecting steel bars are exposed out of the ballast slab within 150mm.

[0029] Then grind off the slag and rusted parts on the surface of the steel bars, and weld stainless steel grounding terminals on them. The welding length of single-sided welding should not be less than 100mm, the welding thickness should be at least 4mm, and the ballast plate should be repaired with resin mortar. Finally, connect the adjacent grounding terminals with a 0.4m long grounding steel cable to restore the comprehensive grounding system in the ballast plate.

[0030] It is particularly noted that the implementation of the track thorough improvement plan of the present invention must be carried out after the stability assessment of the invert meets the requirements for laying ballastless track. Before the arching defects of the tunnel invert are completely improved, fasteners should first be used to make slope adjustments. After the tunnel invert improvement is completed and stable, the track geometry, elevation, etc. should be re-measured, and the fastener adjustment amount should be investigated again. According to the final arching situation of the invert, the track thorough improvement scope, the amount of track drop, etc. should be adjusted.

[0031] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.

Claims

1. The method for cutting and repairing the ballastless track in the tunnel is characterized by: The steps include: 1) Use a total station to measure the line shape, collect track basic data, investigate the thickness of the pad, and determine the range and amount of track drop; 2) Adjust the data according to the renovation length, working time during the window period and the geometric state of the track bed slab, divide it into 1 unit according to a certain length, and mark the cutting position; 3) Plant multiple rows of connecting steel bars along the longitudinal direction of the line from the track slab to the backfill layer of the invert at both ends outside the renovated section; 4) Chisel away the filling layer concrete on both sides of the ballast slab and the filling layer concrete between the lines to form a construction groove; 5) Drill holes on both sides of the remediation unit according to the unit division of the invert filling layer; the wire saw cutting hole is perpendicular to the rail, and the top of the drill hole is located at the interface between the ballast plate and the filling layer; 6) During the operation, within the regulation section, a limit device is set on both sides of the track bed at regular intervals along the longitudinal direction of the line; 7) The rope saw performs vertical cutting in the two construction holes at the ends of the renovation section, and separates the roadbed slab in the renovation section into independent units according to the renovation scope; 8) Use a rope saw to cut vertically downwards in the borehole first and then horizontally, so that the invert filling layer of the part to be cut in the treatment section forms a completely independent construction unit; 9) Push out the cut concrete laterally and use support blocks under each sleeper. The size of the support blocks can be adjusted according to the actual cutting thickness. Rubber gaskets of the same size are set on the top of the support blocks. 10) After all the cutting is completed and the ballast bed is in a stable state, re-measure the geometric state of the ballast bed, determine the final amount of ballast bed plate falling, and do a good job of support and limit; 11) Clean the concrete at the cutting joint, set up the formwork after cleaning, and set up inspection holes on the ballast plate; 12) Steel bars are used to anchor the ballast plate and the tunnel invert filling layer in the renovated section; the spacing of the anchor steel bars is 2 steel bars per sleeper; after the holes are drilled, adhesive is injected into the holes, and finally high-strength grouting material is used to seal and smooth them; 13) Fine-tune the roadbed in the renovated section and conduct CPⅢ retest at the same time; 14) Use concrete of grade no lower than C30 to restore the cushion layer to the original design condition; 15) Partially remove the concrete of the ballast slab in the emergency remediation area and on the top of the sides of the adjacent ballast slab ends; weld the grounding terminal to the steel bar, use resin mortar to repair the ballast slab, and finally connect the adjacent grounding terminal to the grounding steel cable to restore the comprehensive grounding system in the ballast slab.

2. The method for improving the ballastless track in a tunnel by cutting and lowering the arch according to claim 1 is characterized by: The step 3) includes the following contents: the spacing between anchoring steel bars is about 1.3m, the diameter of the drilling hole is 25mm, the depth of the drilling hole is 0.7m, and the hole is injected with steel bar embedding glue. The embedding material is HRB500Ф20 threaded steel bar with a length of 0.6m; The steel bars are inserted to the bottom of the hole and finally sealed and smoothed with grouting material.

3. The method for improving the ballastless track in a tunnel by cutting and lowering the arch according to claim 2 is characterized by: The rebar embedding materials and technology shall comply with the relevant provisions of the Technical Code for Post-Anchorage of Concrete Structures (JGJ 145-2004), the Code for Design of Reinforcement of Concrete Structures (GB 50367-2006), and the Code for Acceptance of Construction Quality of Building Structure Reinforcement Engineering (GB 50550-2010). The rebar embedding glue shall be Class A glue and shall meet the requirements of Class A glue of the Chinese national standard GB50367 and the various requirements for rebar embedding glue in the acceptance standard of GB50550.

4. The method for improving the ballastless track in a tunnel by cutting and lowering the arch according to claim 2 is characterized by: The step 8) includes the following contents: after horizontal cutting, the roadbed plate is supported by a steel pad, and before the skylight is completed, a 1-10 mm thick steel plate is used for combined support in the cutting gap, with a size of 150 mm × 150 mm, and a support spacing of 0.65 m or adjusted according to the actual cutting thickness, and removed before the next skylight operation.

5. The method for improving the ballastless track in a tunnel by cutting and lowering the arch according to claim 2, characterized in that: The step 10) includes the following contents: arranging jacks at each side of the ballast plate every 3m along the longitudinal direction of the line, supporting the ballast plate with the jacks, taking out the supporting pads under the ballast plate, and adjusting the jacks to drop the track; during the track dropping process, the track elevation and plane should be monitored in real time, and after the track is dropped, concrete pads with a strength grade not less than C30 are used for support, the size of the concrete blocks is 300mm×240mm, and the thickness is determined according to the amount of track dropped.

6. The method for improving the ballastless track in a tunnel by cutting and lowering the arch according to claim 5, characterized in that: When the local ballast plate elevation deviates greatly from the design value, the elevation is adjusted by fine-tuning the height of the internal limit device. After the ballast plate is put on the track, the limit device screws on both sides of the ballast plate are tightened, and the geometric state of the adjusted ballast plate is re-measured using a total station and a level. If there is a slight lateral deviation of the ballast plate, it is adjusted using the lateral screws of the limit device.

7. The method for improving the ballastless track in a tunnel by cutting and lowering the arch according to claim 5, characterized in that: The step 11) includes the following contents: the inspection hole has a diameter of 50 mm, is located on the center line of the roadbed slab, and is set at every 2.6 m; the grouting should ensure that the bottom of the slab is dense, and the grouting surface is not less than 10 mm higher than the bottom of the roadbed slab.

8. The ballastless track arch cutting and falling track regulation system in the tunnel is characterized by: The system comprises the method for regulating the upper arch cutting and falling track of the ballastless track in the tunnel as claimed in claim 1 to regulate the upper arch cutting and falling track of the ballastless track in the tunnel.

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