Track anti-eddy current structure applicable to urban modern tram

Abstract

The present invention discloses an anti-eddy current structure for the track of urban modern tramways, which includes an integrated pile plate of the track and the track subgrade. A layer of anti-eddy current steel bar distribution network is provided on the upper surface of the integrated pile plate of the track subgrade; the anti-eddy current steel bar distribution network includes a plurality of longitudinal steel bars and a plurality of transverse steel bars; the longitudinal steel bars closest to both sides of each of the multiple sleepers under each track are drainage steel bars and are connected to the intersecting transverse steel bars; the multiple transverse steel bars include inner transverse steel bars, outer transverse steel bars and full-width transverse steel bars; every 3 to 5 full-width transverse steel bars form a transverse steel bar loop; the first full-width transverse steel bar and the last full-width transverse steel bar in each transverse steel bar loop are fixedly connected to the intersecting longitudinal steel bars; each inner transverse steel bar and each outer transverse steel bar are firmly tied to the intersecting longitudinal steel bars. The present invention can more effectively and reliably achieve the induction and drainage of eddy current, and has zero impact on the track fastener system, and is safer and more reliable.

Description

Technical Field

[0001] The present invention relates to the technical field of tram construction, and particularly to an anti-stray current structure for tracks applicable to modern urban trams. Background Art

[0002] In a rail transit system that mostly adopts a DC traction system, the traction current is sent out from the positive pole of a traction substation, passes through an overhead contact line, a vehicle, and a rail, and returns to the negative pole of the traction substation.

[0003] Due to the non-complete insulation between the rail and the roadbed and the ground, a part of the current flowing through the rail leaks into the ground. This part of the current leaking into the ground is called stray current, also known as eddy current.

[0004] Stray current can cause electrochemical corrosion of surrounding buried metal pipelines, etc., thereby damaging their strength and reducing their lifespan. Stray current causes corrosion of underground cables, oil and gas, water supply, and other metal pipelines, resulting in damages such as "leakage, seepage, dripping, and running", and causing serious accidents such as explosions, fires, and environmental pollution.

[0005] Therefore, stray current has been regarded as a new public hazard in rail transit construction.

[0006] Scientific research shows that the magnitude and specific distribution of stray current are related to the following factors around the roadbed: the position of underground metal objects, the difference in soil conductivity, meteorological conditions, and pollution degree, etc.

[0007] Modern trams, as a public transportation system set above urban municipal roads, have obvious differences from other rail transit forms such as subways, high-speed rails, and light rails in the above aspects.

[0008] High-speed rails are located in the blank areas between cities, and light rails use bridge overheads, so there is basically no problem of preventing stray current for surrounding buried metal pipelines.

[0009] Subways are usually buried about 20 - 30 m underground. Firstly, the roadbed is far from the shallow metal pipelines of municipal roads, so the influence is small. Secondly, the surrounding soil layers at the buried depth of the roadbed are relatively stable or dense, and the soil conditions are good. Thirdly, the roadbed is set in a closed station or section, and the reinforced concrete walls or segments can better isolate surrounding water, soil, atmosphere and other natural factors, and the surrounding environment is more favorable.

[0010] For modern trams, on the one hand, since the roadbed is buried about 1.0 m below the municipal road, it is surrounded by a dense and complex metal pipeline network nearby. Stray current will largely concentrate and flow along the metal pipelines, and the shallow soil properties are poor.

[0011] On the other hand, considering the greening paving of the urban landscape, the roadbed is directly in contact with water and soil, and is severely affected by rainwater and the atmosphere.

[0012] Therefore, higher-demand protected objects, more unfavorable soil conditions, and harsher surrounding environments have put forward more stringent demands on the prevention of stray flow in modern urban trams.

[0013] The prevention of stray flow in rail transit follows the principle of "combining blocking and drainage".

[0014] "Blocking" mainly increases the resistance between the rail and the ballast bed. The traditional approach is to use nylon gauge blocks, rubber pads and other components with good insulation in the rail fastener system to increase the resistance. Some scholars have proposed to increase the resistance by setting up a wrapping system with good sealing and insulation for the rail.

[0015] "Discharge" mainly collects the current conducted from the track to the ballast bed through some of the main structural steel bars, and then leads and discharges the current to the substation.

[0016] However, these existing anti-stray flow measures cannot meet the more stringent anti-stray flow requirements of modern urban trams.

[0017] On the one hand, the insulating components or wrapping systems not only make the fastener system more and more complicated, but also increase the risk factor due to material instability, and the project investment increases sharply, resulting in poor economic benefits. It should also be pointed out that the modern tram track bed is directly in a humid environment or open air environment due to green paving, and the above measures are more susceptible to corrosion, damage, and failure than other forms of rail transportation.

[0018] On the other hand, using part of the main structural steel bars for drainage cannot meet the stringent protection requirements of the adjacent dense and complex shallow metal pipe network. Secondly, since stray flow can easily cause steel corrosion, the relevant design specifications for modern trams clearly require that the main structural steel bars should not be used as drainage measures.

[0019] Therefore, how to provide a set of applicable, simple, effective, reliable, and economically reasonable anti-stray flow measures in response to the above-mentioned engineering characteristics and problems of modern trams is a difficult technical problem that the industry urgently needs to solve. Summary of the invention

[0020] In view of the above-mentioned defects of the prior art, the present invention provides a track anti-stray flow structure suitable for modern urban trams, which aims to more effectively and reliably guide and drain stray flow, has a simple structure, can be quickly installed on site, further improves production efficiency, and has zero impact on the track fastener system, making it safer and more reliable.

[0021] To achieve the above object, the present invention discloses a track anti-stray flow structure suitable for modern urban trams, comprising a track and a track-roadbed integrated pile plate arranged under the track.

[0022] Among them, a layer of anti-eddy current steel bar distribution network is provided on the upper surface of the integrated pile slab of the track subgrade;

[0023] The anti-eddy current steel bar distribution network includes multiple longitudinal steel bars extending along the track and multiple transverse steel bars perpendicular to the extension direction of the track;

[0024] On both sides of each of the multiple sleepers under each track, the longitudinally closest steel bars are connected to all the intersecting transverse steel bars as drainage steel bars;

[0025] Among the multiple transverse steel bars, there are inner transverse steel bars arranged between the two tracks, outer transverse steel bars arranged outside the two tracks, and full-width transverse steel bars arranged between two adjacent sleepers;

[0026] Every 3 to 5 full-width transverse steel bars along the extension direction of the track form a transverse steel bar loop;

[0027] The first full-width transverse steel bar and the last full-width transverse steel bar in each transverse steel bar loop are fixedly connected to all the intersecting longitudinal steel bars;

[0028] Each inner transverse steel bar and each outer transverse steel bar are firmly tied to all the intersecting longitudinal steel bars to form a combined potential body.

[0029] Preferably, each drainage steel bar is connected to all the intersecting transverse steel bars by welding;

[0030] The first full-width transverse steel bar and the last full-width transverse steel bar in each transverse steel bar loop are fixedly connected to all the intersecting longitudinal steel bars by welding.

[0031] Preferably, each longitudinal steel bar is formed by sequentially connecting the heads and tails of multiple steel bars of standard length;

[0032] Between any two adjacent standard-length steel bars in each longitudinal steel bar, lap joint is adopted for connection, and all lap joint parts are fixed by lap welding.

[0033] Preferably, the distance between every two adjacent longitudinal steel bars is a; the distance between every two adjacent transverse steel bars is b; a and b need to satisfy the following relationship:

[0034]

[0035] {a, b} ≤ {600, Δ0};

[0036] Among them, is the factor of adjacent buried metal pipelines; is the factor of the pressurized pipeline; is the factor of the non-pressurized pipeline; L `1a is the minimum distance from the pressurized metal pipeline within the adjacent 5 m to the roadbed; L `1b is the minimum distance from the non-pressurized metal pipeline within the adjacent 5 m to the roadbed, taking 1.5 when the two are less than 1.5 m; η 1a is the correction coefficient of the pressurized pipeline, taking 0.2 - 0.5; η 1b is the correction coefficient of the non-pressurized pipeline, taking 0.5 - 0.8; η 1a and η 1b are both selected inversely according to the pipe diameter and the importance of the function; is the factor of the soil property around the roadbed; η 2a is the soil body correction coefficient; η 2b is the correction coefficient of the steel bar diameter; d s is the diameter of the longitudinal steel bar and the transverse steel bar; Δ0 is the spacing of the sleepers along the longitudinal direction of the line;

[0037] η 2a and η 2b are specifically valued as follows:

[0038] When the soil body type is silt or silty soil, η 2a is 0, η 2b is 1.0;

[0039] When the soil body type is artificial fill, plain fill or miscellaneous fill, η 2a is 1.0, η 2b is 1.0;

[0040] When the soil body type is cohesive soil with a liquidity index ≥ 0.8, η 2a is 1.0, η 2b is 1.0;

[0041] When the soil body type is large-area compacted fill and is silt with a compaction coefficient > 0.95 and a clay particle content ≥ 10%, η 2a is 1, η 2b is 1.5;

[0042] When the soil body type is large-area compacted fill and is graded sand and gravel with a dry density ≥ 20 kg / m 3 η 2a is 1, η 2b is 2.0;

[0043] When the soil body type is silt with a clay particle content ≥ 10%, η 2a is 0.3, η 2b is 1.5;

[0044] When the soil type is silt with clay content < 10%, η 2a is 0.5, and η 2b is 2.0;

[0045] When the soil type is cohesive soil with liquidity index < 0.8, η 2a is 1.0, and η 2b is 1.4;

[0046] When the soil type is silty sand or fine sand, η 2a is 2.0, and η 2b is 3.0;

[0047] When the soil type is medium sand, coarse sand, gravel sand or gravel soil, η 2a is 3.0, and η 2b is 4.0.

[0048] Preferably, the spacing c between the first full-width transverse steel bar and the last full-width transverse steel bar in each transverse steel bar ring is 3 m when the track adopts green vegetation, and the rest is 5 m.

[0049] Preferably, the transverse steel bars closest to both sides of each structural joint in the integrated pile slab of the track subgrade are all full-width transverse steel bars, and both serve as the first full-width transverse steel bar or the last full-width transverse steel bar in the corresponding transverse steel bar ring.

[0050] More preferably, transverse hot-dip galvanized flat steel bars are provided on the full-width transverse steel bars closest to both sides of each structural joint;

[0051] Both ends of the two transverse hot-dip galvanized flat steel bars closest to both sides of each structural joint are connected by longitudinal hot-dip galvanized flat steel bars.

[0052] Advantages of the present invention:

[0053] First of all, in view of the engineering characteristics of modern tramway beds with shallow burial depth, contact with water, soil, atmosphere, etc. of the rails, and comprehensively considering the influence of ultra-close metal pipe networks, shallow soil properties, and the surrounding environment of the roadbed, through engineering summary, coupling analysis, and parameter induction, the present invention provides an anti-eddy current measure applicable to urban modern trams, filling the gap in the modern tram industry and promoting the technological progress of the industry.

[0054] Secondly, the structure of the present invention is simple, enabling rapid on-site installation and further improving production efficiency.

[0055] Thirdly, the present invention is effective and reliable, enabling better induction and drainage of eddy currents, and having zero impact on the track fastener system, being safer and more reliable.

[0056] Finally, the project investment of the present invention is small, and it has better economic benefits.

[0057] The concept, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings to fully understand the purpose, features and effects of the present invention. Description of the Drawings

[0058] Figure 1 Shows a schematic plan view of the stray current prevention steel bar distribution network in an embodiment of the present invention.

[0059] Figure 2 Shows a schematic view of the structure in the AA direction in an embodiment of the present invention.

[0060] Figure 3 Shows a schematic view of the structure in the BB direction in an embodiment of the present invention. Detailed Description of the Invention

[0061] Embodiment 1

[0062] As Figures 1 to 3 shown, a stray current prevention structure for an urban modern tram track includes a track 13 and an integrated pile-slab for track subgrade 12 provided under the track 13.

[0063] Among them, a layer of stray current prevention steel bar distribution network is provided on the upper surface of the integrated pile-slab for track subgrade 12;

[0064] The stray current prevention steel bar distribution network includes a plurality of longitudinal steel bars 1 extending along the track 13 and a plurality of transverse steel bars perpendicular to the extension direction of the track 13;

[0065] The two longitudinal steel bars 1 closest to both sides of each of the multiple sleepers 2 under each track 13 are connected to all the intersecting transverse steel bars to serve as drainage steel bars 3;

[0066] The multiple transverse steel bars include inner transverse steel bars provided between the two tracks 13, outer transverse steel bars 6 provided outside the two tracks 13, and full-width transverse steel bars provided between two adjacent sleepers 2;

[0067] Every 3 to 5 full-width transverse steel bars along the extension direction of the track 13 form a transverse steel bar loop 4;

[0068] The first full-width transverse steel bar and the last full-width transverse steel bar in each transverse steel bar loop 4 are fixedly connected to all the intersecting longitudinal steel bars 1;

[0069] Each inner transverse steel bar and each outer transverse steel bar 6 are firmly tied to all the intersecting longitudinal steel bars 1 to form a combined potential body.

[0070] In some embodiments, each drainage steel bar 3 is connected to all the intersecting transverse steel bars by welding;

[0071] The first full-width transverse steel bar and the last full-width transverse steel bar in each transverse steel bar loop 4 are fixedly connected to all the intersecting longitudinal steel bars 1 by welding.

[0072] In some embodiments, each longitudinal steel bar 1 is formed by sequentially connecting the ends of multiple standard-length steel bars;

[0073] Between any two adjacent standard-length steel bars in each longitudinal steel bar 1, lap joint connection is adopted, and all lap joint parts 8 are fixed by lap welding.

[0074] In some embodiments, the spacing between every two adjacent longitudinal steel bars 1 is a; the spacing between every two adjacent transverse steel bars is b; a and b need to satisfy the following relational expression:

[0075]

[0076] {a, b} ≤ {600, Δ0};

[0077] Wherein, is the factor of adjacent buried metal pipeline; is the factor of pressurized pipeline; is the factor of non-pressurized pipeline; L `1a is the minimum distance from the pressurized metal pipeline within 5 m adjacent to the ballast bed; L `1b is the minimum distance from the non-pressurized metal pipeline within 5 m adjacent to the ballast bed, and when the two are less than 1.5 m, take 1.5; η 1a is the correction coefficient of pressurized pipeline, taking 0.2 - 0.5; η 1b is the correction coefficient of non-pressurized pipeline, taking 0.5 - 0.8; η 1a and η 1b are both selected inversely according to the pipe diameter and functional importance; is the factor of soil property around the ballast bed; η 2a is the soil body correction coefficient; η 2b is the correction coefficient of steel bar diameter; d s is the diameter of the longitudinal steel bar 1 and the transverse steel bar; Δ0 is the spacing of the sleepers 2 along the longitudinal direction of the line;

[0078] η 2a and η 2b The specific values are as follows:

[0079] When the soil type is silt or silty soil, η 2a is 0, η 2b is 1.0;

[0080] When the soil type is artificial fill, plain fill or miscellaneous fill, η 2a is 1.0, and η 2b is 1.0;

[0081] When the soil type is cohesive soil with a liquidity index ≥ 0.8, η 2a is 1.0, and η 2b is 1.0;

[0082] When the soil type is large - area compacted fill and is silt with a compaction coefficient greater than 0.95 and a clay particle content ≥ 10%, η 2a is 1, and η 2b is 1.5;

[0083] When the soil type is large - area compacted fill and is graded sand and gravel with a dry density ≥ 20 kg / m 3 , η 2a is 1, and η 2b is 2.0;

[0084] When the soil type is silt with a clay particle content ≥ 10%, η 2a is 0.3, and η 2b is 1.5;

[0085] When the soil type is silt with a clay particle content < 10%, η 2a is 0.5, and η 2b is 2.0;

[0086] When the soil type is cohesive soil with a liquidity index < 0.8, η 2a is 1.0, and η 2b is 1.4;

[0087] When the soil type is fine sand or silty sand, η 2a is 2.0, and η 2b is 3.0;

[0088] When the soil type is medium sand, coarse sand, gravelly sand or gravel soil, η 2a is 3.0, and η 2b is 4.0.

[0089] In some embodiments, the spacing c between the first full - width transverse steel bar and the last full - width transverse steel bar in each transverse steel bar ring 4 is 3 m when the track 13 adopts green vegetation, and 5 m for the rest.

[0090] In some embodiments, the transverse steel bars closest to both sides of each structural joint 9 in the integrated pile - slab of the track subgrade 12 are all full - width transverse steel bars, and both serve as the first full - width transverse steel bar or the last full - width transverse steel bar in the corresponding transverse steel bar ring 4.

[0091] In some embodiments, transverse hot-dip galvanized flat steels 10 are provided for the full-width transverse steel bars closest to both sides of each structural joint 9.

[0092] Both ends of the two closest transverse hot-dip galvanized flat steels 10 on both sides of each structural joint 9 are connected by a longitudinal hot-dip galvanized flat steel 11.

[0093] Embodiment 2

[0094] On the basis of Embodiment 1, assume a modern tram project. The soil layer where the bed is buried is miscellaneous fill; the buried metal pipelines within 5 m nearby are: a cast iron gas pipeline with a diameter of φ300 mm, 1.3 m away from the bed, φ500 mm, 2.8 m away from the bed, a steel water supply pipeline with a diameter of φ500 mm, 1.9 m away from the bed, a cast iron rainwater pipeline with a diameter of φ800 mm, 3.1 m away from the bed, and a cast iron sewage pipeline with a diameter of φ600 mm, 4.3 m away from the bed; the diameter of the steel bar distribution network is selected as 16 mm according to the overall project plan.

[0095] Then:

[0096] There are pressurized metal pipelines nearby:

[0097] For the cast iron gas pipeline with a diameter of φ300 mm, η 1a = 0.35, L `1a = 1.5;

[0098] For the cast iron gas pipeline with a diameter of φ500 mm, η 1a = 0.25, L `1a = 2.8;

[0099] For the steel water supply pipeline with a diameter of φ500 mm, η 1a = 0.4, L `1a = 1.9;

[0100]

[0101] There are non-pressurized metal pipelines nearby:

[0102] For the cast iron rainwater pipeline with a diameter of φ800 mm, η 1a = 0.65, L `1a = 3.1;

[0103] For the cast iron sewage pipeline with a diameter of φ600 mm, η 1a = 0.75, L `1a = 4.3;

[0104]

[0105] Therefore,

[0106] In addition, the soil correction coefficient η 2a= 1.0; Steel bar diameter correction coefficient η 2b = 1.0, steel bar diameter d s = 16 mm; The spacing Δ0 of the sleepers 2 along the line longitudinally is 667 mm;

[0107] Therefore, mm.

[0108] mm;

[0109] Therefore, the longitudinal steel bar spacing is a, and the transverse steel bar spacing b is taken as 330 mm.

[0110] And for this modern tram project, the bed paving uses green vegetation. Therefore, the spacing c between the first full-width transverse steel bar and the last full-width transverse steel bar in each transverse steel bar loop 4 is 3 m.

[0111] The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations based on the concept of the present invention without creative work. Therefore, all technical solutions that can be obtained by those skilled in the art in the technical field of the present invention based on the concept of the present invention through logical analysis, reasoning, or limited experiments on the basis of the prior art should be within the protection scope determined by the claims.

Claims

1. The track anti-eddy current structure applicable to urban modern tramways includes a track (13) and an integrated pile slab of track roadbed (12) arranged under the track (13); it is characterized in that, The upper surface of the integrated pile - slab of the track subgrade (12) is provided with a layer of anti - stray current steel bar distribution network; The anti - stray current steel bar distribution network includes multiple longitudinal steel bars (1) extending along the track (13) and multiple transverse steel bars perpendicular to the extension direction of the track (13); On both sides of each of the multiple sleepers (2) under each track (13), the closest longitudinal steel bars (1) to the sleepers are connected to all the intersecting transverse steel bars, serving as drainage steel bars (3); Among the multiple transverse steel bars, there are inner transverse steel bars arranged between the two tracks (13), outer transverse steel bars (6) arranged outside the two tracks (13), and full - width transverse steel bars arranged between two adjacent sleepers (2); Every 3 to 5 full - width transverse steel bars along the extension direction of the track (13) form a transverse steel bar loop (4); The first full - width transverse steel bar and the last full - width transverse steel bar in each transverse steel bar loop (4) are fixedly connected to all the intersecting longitudinal steel bars (1); Each inner transverse steel bar and each outer transverse steel bar (6) are firmly tied to all the intersecting longitudinal steel bars (1) to form a combined potential body; The distance between every two adjacent longitudinal steel bars (1) is a; the distance between every two adjacent transverse steel bars is b; a and b need to satisfy the following relationship: {a,b}≤{600,Δ0}; Among them, is the factor of the adjacent buried metal pipeline; is the factor of the pressurized pipeline; is the factor of the non-pressurized pipeline; L `1a is the minimum distance from the pressurized metal pipeline within 5 m adjacent to the ballast bed; L `1b is the minimum distance from the non-pressurized metal pipeline within 5 m adjacent to the ballast bed, and when the two are less than 1.5 m, take 1.5; η 1a is the correction coefficient of the pressurized pipeline, taking 0.2 - 0.5; η 1b is the correction coefficient of the non-pressurized pipeline, taking 0.5 - 0.8; η 1a and η 1b are both selected in inverse proportion according to the pipe diameter and the importance of the function; is the factor of the soil property around the ballast bed; η 2a is the soil body correction coefficient; η 2b is the correction coefficient of the steel bar diameter; d s is the diameter of the longitudinal steel bar (1) and the transverse steel bar; Δ0 is the spacing of the sleepers (2) along the longitudinal direction of the line; η 2a and η 2b take the following specific values: When the soil type is silt or silty soil, η 2a is 0, and η 2b is 1.0; When the soil type is artificial fill, plain fill or miscellaneous fill, η 2a is 1.0, and η 2b is 1.0; When the soil type is cohesive soil with a liquidity index ≥ 0.8, η 2a is 1.0, and η 2b is 1.0; When the soil type is large-area compacted fill and it is silt with a compaction coefficient greater than 0.95 and a clay particle content ≥ 10%, η 2a is 1, and η 2b is 1.5; When the soil type is large-area compacted fill and it is graded sand and gravel with a dry density ≥ 20 kg / m 3 , η 2a is 1 and η 2b is 2.0; When the soil type is silt with clay content ≥ 10%, η 2a is 0.3, and η 2b is 1.5; When the soil type is silt with clay content < 10%, η 2a is 0.5, and η 2b is 2.0; When the soil type is cohesive soil with a liquidity index < 0.8, η 2a is 1.0, and η 2b is 1.4; When the soil type is silt or fine sand, η 2a is 2.0, and η 2b is 3.0; When the soil type is medium sand, coarse sand, gravel sand or gravelly soil, η 2a is 3.0, and η 2b is 4.

0.

2. The track stray current prevention structure applicable to urban modern tramways according to claim 1, wherein Each drainage steel bar (3) is connected to all the intersecting transverse steel bars by welding; The first full - width transverse steel bar and the last full - width transverse steel bar in each transverse steel bar loop (4) are fixedly connected to all the intersecting longitudinal steel bars (1) by welding.

3. The track anti-eddy current structure applicable to urban modern tramways according to claim 1, characterized in that, Each longitudinal steel bar (1) is formed by sequentially connecting the heads and tails of multiple standard - length steel bars; Between any two adjacent standard - length steel bars in each longitudinal steel bar (1), they are connected by lap joint, and all lap joints (8) are fixed by lap welding.

4. The track anti-eddy current structure applicable to urban modern tramways according to claim 1, characterized in that, The distance c between the first full - width transverse steel bar and the last full - width transverse steel bar in each transverse steel bar loop (4) is 3m when the track (13) adopts green vegetation, and 5m for the rest.

5. The track anti-eddy current structure applicable to urban modern tramways according to claim 1, characterized in that, Among the full - width transverse steel bars closest to both sides of each structural joint (9) in the integrated pile - slab of the track subgrade (12), they are all full - width transverse steel bars, and they serve as the first full - width transverse steel bar or the last full - width transverse steel bar in the corresponding transverse steel bar loop (4).

6. The track anti-eddy current structure applicable to urban modern tramways according to claim 5, characterized in that, Transverse hot - dip galvanized flat steel (10) is provided on the full - width transverse steel bars closest to both sides of each structural joint (9); The two ends of the two closest transverse hot - dip galvanized flat steel (10) on both sides of each structural joint (9) are connected by longitudinal hot - dip galvanized flat steel (11).

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