WO2015067977A1

WO2015067977A1 - Structural arrangement and procedure for the stabilisation of linear earthworks

Info

Publication number: WO2015067977A1
Application number: PCT/HU2014/000091
Authority: WO
Inventors: József SZABÓ; Róbert HORVÁTH; János KONDOR
Original assignee: Szabó József; Horváth Róbert; Kondor János
Priority date: 2013-11-08
Filing date: 2014-10-06
Publication date: 2015-05-14
Also published as: SK8034Y1; HUP1300644A2; AT16231U8; HRPK20160491B3; SK500752016U1; AT16231U1; HRP20160491A2; DE212014000211U1

Abstract

The subject of the invention relates to a structural arrangement for the stabilisation of linear earthworks, i.e. mainly railway line superstructures, for the prevention of movements of the superstructure due to the effect of forces transverse to the direction of the trace line, whilst intermittently maintaining traffic. The invention's distinctive feature is that the load-bearing support structure is made up of a support beam (3) stabilising the ballast bed (21) and running alongside the trace line on the side of the sleepers (22) where movements tend to occur, and a supporting wall (4) located at the other side of the support beam (3) opposite the sleepers (22), extending from the superstructure (2) down towards the subsoil, and a protective blanket (5) covering the support beam (3) and the supporting wall (4), simultaneously embracing the ends (22a) of the sleepers (22) facing towards the support beam (3). The invention also encompasses the procedure for creating the structural arrangement; this procedure involves building the support beam (3) stabilising the sleepers (22), which are part of the railway superstructure, and the ballast bed (21) under them, and running alongside the trace line on the side of the sleepers (22) where movements tend to occur, and constructing, when indicated, a supporting wall (4) in the earth lying up against the other side of the support beam (3) opposite the sleepers (22), covering the support beam (3) and the supporting wall (4) with a covering blanket (5), and constructing a drain (7) underneath the supporting wall (4) if necessary.

Description

Structural arrangement and procedure for the stabilisation of linear earthworks

The subject of the invention relates to a structural arrangement for the stabilisation of linear earthworks, i.e. mainly railway line superstructures, for the prevention of movements of the superstructure due to the effect of primarily transverse (horizontal) forces in relation to the direction of the trace line, whilst intermittently maintaining traffic; this arrangement contains a load-bearing support structure which is preferably located outside the railway structure gauge, and resists to the movements that tend to occur, at the location of occurrence. The subject of the invention also includes the procedure during which the load-bearing support structure is created.

When building or renovating, e.g. reinforcing public roads, but especially railway line sections running along contour lines on sloped terrain, in particular on mountainsides or hillsides, the stabilisation of the earthwork may be an important task, especially if the cross- section of the line resembles a cutting on the ascending "inner" (e.g. hill) side of the terrain while displaying an embankment shape on the sloped, "outer" side of the terrain.

Railway lines require special care as they involve the movement of heavy-weight and elongated loads, and their combined and repetitive occurrence dynamic effects. More precisely, those line sections or curved line sections demand special attention where apart from the unique cross-sectional features more than one track are built next to each other on the railway line along the contour line.

In the case of linear earthworks, it has been a requirement for many decades that railway lines running along contour lines on sloped terrain sooner or later require stabilisation. As we have seen, the most difficult and complex construction conditions occur in the case of railway lines, therefore the various technical initiatives and the experience gained go back farthest in time in this area. An obvious idea for stabilisation seemed to be to use sheet piling, which is well approved for the planned supporting of the soil in other areas. This method essentially means that steel sheets that are linked to each other along the longitudinal edges are driven into the soil, and the sheet sections that are driven down to a sufficient depth provide suitable support for the sections standing freely as a console in such a way that they are able to safely protect the excavation pit from the surrounding earth sliding in.

However, sheet piling did not prove to be suitable to perform the present task for several reasons. Driving the sheet piles into the earth causes damaging vibration; the piles have to be driven down to a disproportionately large depth; water drainage causes a problem; when the work is completed, and the sheet piles are removed, the ground water seeping into their place has a damaging effect to the entire earthwork. In addition, anchoring on the hill-side of the earthwork poses major difficulties, and it is mostly impossible to solve. Another difficulty arises on electrified lines, where the overhead lines have to be dismantled during the installation of the sheet piling. During this period only other forms of traction may be used (e.g. with diesel locomotives), which involves significantly higher costs, and when the work is completed, the overhead lines may only be reinstalled after the sheet piling has been removed.

The new solutions developed over the past decades have not been overly successful either. An example can be found in the patent document JPH 05125739 from 1991. It offers a solution for the construction of a self-supporting retaining wall without shuttering. It achieves stabilisation with the construction of an inclined supporting wall made of concrete blocks along the embankment-type sloped earth surface with a base that penetrates into the inside of the embankment. This solution is unsuitable for our purpose due to the latter feature, as the repeated load with its dynamic effect may cause the displacement of this stabilising base.

The arrangement presented in the patent document JPH 11293648 from 1998 is more or less similar: It was developed for covering an inclined embankment bordering a riverbank. In this case, a further layer is fixed to the river-side surface of an existing concrete wall, which is suitable for the cultivation of plants. Its disadvantage - from our point of view - is that the new layer has no stabilising effect reinforcing the original wall, and the U-shaped connection pieces gripping the wall even weaken it locally. The Hungarian priority publication document P 00 03768 from 2000 presents a procedure aimed specifically at the stabilisation of earthworks constructed from prefabricated surface elements. According to the undoubtedly clever idea, reinforced concrete fixing supports - e.g. concreted steel pipes - are driven into the earth in the vicinity of the structure supporting the embankment earthwork, and are linked to the structure supporting the earthwork with the help of tension cables. This method cannot be considered for solving our task either, partially because of its great cost, and partially because as time passes the gripping heads of the tension cables will need to be accessed periodically - due to the repeating dynamic effects occurring in our case - which is technically impossible.

The publication document KR 2003/0097085 published in 2003 is interesting, but unsuitable for our purposes. Its subject is a supporting wall that can be constructed in steps from top to bottom. It is undoubtedly true that theoretically it may be used to support the inclined side of an earthwork, but it is constructed at the location where, due to the dynamic effects, the stabilising, reinforcing structure itself is also subject to the risk of sliding.

The more recent document CN 102733354 from 2012 proposes the combination of large mass anti-slide constructions with sheet piling, which aims to achieve the immobility of the construction by adding a large-weight superstructure to it. Due to its complexity and costliness it is unlikely that this method will become popular. This is all the more true in our case, because piles have to be driven down to create the construction, which has an unfavourable influence on the stability of the natural soil (internal friction).

The aim of the invention is the reliable stabilisation of railway lines running over sloped terrain, characteristically along a contour line, and mainly of railway lines with a cross-section displaying a cutting on the hill side and an embankment on the valley side. Within this scope, the invention also aims to eliminate the damaging effect of surface water on the line sections held back directly by them, and water arriving indirectly due to the inclination of the terrain.

The task of the invention in the case of uniquely sensitive dual-track railway lines is to ensure that traffic can be maintained - if just intermittently - on the hill-side, inner track without disturbance while reinforcing the valley-side outer track, even if soil replacement has to be carried out in the given sections. The basis of the idea behind the invention is the realisation that stabilisation may be performed most effectively, if the ballast bed forming a part of the superstructure can be established in such a way that the movements which tend to occur as a result of the transverse forces and, along with them, the destabilising effect of surface water under-cutting the track can be prevented. By achieving this, the task can be solved.

The realisation also includes that originally the elements of the high-strength, crushed stone ballast bed are connected with each other through strong friction, and are layered over one another. This internal friction has been able to exert such a resistance that, up to a certain point, was able to resist the movements created as a result of the forces transverse to the direction of the line. In our point of view, this resistance can be greatly increased, if we do not permit the individual elements and layers of the ballast bed to slide over one another at all, in other words, if we insert adhesive material in between them. The adhesive material does not fill up the space between the stones (the so called void volume) but rather leaves a significant proportion of it free, and this way the water-permeable "grid" structure of the ballast remains intact.

In accordance with the goal we have set, the structural arrangement according to the invention for the stabilisation of linear earthworks, and mainly railway line superstructures, in order to prevent movements of the superstructure occurring due to the effect of primarily transverse forces in relation to the direction of the trace line while intermittently maintaining traffic, contains a load-bearing support structure preferably located outside of the railway structure gauge and resistant to the movements that tend to occur at the section where the movements occur, and is set up in such a way that the load-bearing support structure is formed by a support beam located alongside of the railway line, stabilising the ballast bed on the side of the sleepers where the movements tend to occur, a supporting wall extending from the superstructure towards the subsoil installed on the side of the support beam opposite to the sleepers, and a protective blanket covering the support beam and the supporting wall, which simultaneously embraces the ends of the sleepers facing towards the support beam.

A further characteristic of the arrangement is that the covering blanket protrudes between the sleepers approximately up to the line of the rail located closer to the supporting structure. The support beam, the supporting wall and the covering blanket all contain high-strength crushed stone, preferably compacted crushed stone, as well as adhesive material, e.g. artificial resin, covering the stone from above and filling a minimal part of its void volume.

The supporting wall is constructed from at least one, but preferably several layers installed on top of each other. In the case of a multi-layered supporting wall, the strength of the individual layers differs and conforms to the size of the load on them. The strength of the layers is in proportion with the amount of adhesive material according to the mass of the ballast bed. The amount of the adhesive material used for the higher-strength layers of the supporting wall exceeds the amount of the adhesive material used for the lower-strength layers.

A drain suitable for draining transmitted dampness, especially rainwater, is installed along the level of the supporting wall which is most distant from the track level. The drain is located at the bottom of the lowest layer of the supporting wall.

The support beam and the supporting wall are fitted to each other seamlessly. The ends of the sleepers located near the support beam are fitted seamlessly to the covering blanket.

In the case of a possible embodiment of the arrangement, the upper layer of the natural soil forming a part of the substructure connected to the external side of the supporting wall most distant from the track line is treated with a strengthening additive or injection. In the case of another embodiment, if the supporting wall runs along an embankment, the inclined side surface of the embankment is strengthened with supplementary structures on one or more levels to stabilise the substructure.

The procedure according to the invention for the stabilisation of linear earthworks, mainly in the case of railway superstructures for the prevention of movements of the superstructure occurring due to the effect of transverse forces in relation to the direction of the trace line while intermittently maintaining traffic, which entails the creation of a load-bearing support structure on a section where movements tend to occur due to forces, e.g. thermal forces created in the railway track, and which is resistant to these forces and preferably located outside of the railway structure gauge either in the ballast bed itself or as a connected structure, is based on a support beam being constructed running alongside the track line on the side of the sleepers forming a part of the railway superstructure where the movements tend to occur, and preventing the movement of the ballast under the sleepers as well as of the sleepers themselves, and on a supporting wall being constructed in the earth on the other side of the support beam, opposite the sleepers, lying up against the support beam. The support beam and the supporting wall are covered with a covering blanket, and if necessary, a drain is constructed under the supporting wall.

A further characteristic of the procedure is that along the side of the support beam opposite the sleepers, the supporting wall or the support beam are constructed from a single layer or from several layers located on top of each other.

Crushed stone, preferably crushed stone of the same material and size of the superstructure ballast is used for the construction of the support beam and supporting wall. The crushed stone is spread out at the planned location after the soil excavation, then levelled out and compacted. A highly fluid adhesive material is applied to its top, then a part of the adhesive material is permitted to seep down through the entire thickness of the crushed stone layer, and then the adhesive material is left undisturbed to solidify for a bonding time complying with its nature, consistency and the ambient temperature.

When constructing the support beam and the supporting wall, the crushed stone is spread out in one or more layers, each layer is compacted separately, then after compaction the adhesive material is applied to the compacted crushed stone preferably throughout the entire thickness of the support beam and the supporting wall, but the compacted void volume is maintained at an approximately unchanged level.

When creating the covering blanket, the crushed stone forming the covering blanket is spread out in a single layer over the completed and hardened support beam and supporting wall reinforced with adhesive material, then adhesive material is applied to it.

The supporting wall is constructed to extend underneath the ground surface to such an extent that the supporting wall is made from several layers created one after the other and above one another. In the case of a multi-layer supporting wall, when constructing the bottommost layer and then, following this, constructing the upper layers, the adhesive material in the supporting wall layer underneath is left to solidify before spreading out the crushed stone of each following layer. When constructing the bottommost layer, the drain is installed before spreading out the crushed stone. In the case of a multi-layer supporting wall, the strength of the individual layers is adjusted to the size of the loads exerted on them. At least one layer of a multi-layer supporting wall located at a deeper level than the support beam is constructed to have greater strength than the other layers, and this greater strength is achieved by increasing the amount of adhesive material in this layer or by using adhesive material of a greater strength.

The "inner" side surface of the supporting wall facing the track is made to fit seamlessly to the support beam. The strength of the upper layer of the natural soil along the "outer" side surface of the supporting wall opposite the side facing the track is increased (e.g. by adding cement). If the supporting wall runs along an embankment, the substructure is fitted with supplementary structures.

The structural arrangement according to the invention and the procedure for its construction has numerous advantageous characteristics as compared to previous earthwork stabilisation methods. The most important of these is that the combination of the high- strength ballast material and the high-strength adhesive material results in a favourable construction material which, when combined with a support beam and supporting wall containing concrete and adhesive material as well, is completely safe and outperforms all other earthwork stabilisation methods. In the case of certain mechanical loads, it is possible to increase the strength (resistance against bending) of the glued crushed stone blanket or of the support beam with steel reinforcement (in the case of the blanket, with steel reinforcing mats). All this results in a long lifetime, and is achieved with simple technology and by using materials conventionally used in the case of railway lines.

It is also favourable that the operations do not incur any transportation or storage problems. The method does not require any structural parts that have to be dismantled at a later time, it may be realised faster than other solutions applied to date, and besides fully satisfying the strength requirements, the possibility of optimal water draining is also provided. It is also important that the structure can be continuously monitored and checked during its total operation time. It is also noteworthy that it prevents numerous side effects of the traditional sheet piling stabilisation, and beside this, it makes huge financial savings possible. According to our calculations it incurs just one third of the costs as compared to the sheet piling procedure.

The invention is presented in more detail in connection with embodiments on the basis of drawings. In the appended drawings

Figure 1 shows the cross-section of a railway line section,

Figure 2 shows the ground plan of the same railway line section,

Figure 3 shows a small detail of the ballast bed.

Figure 1 shows the earthwork forming the substructure of the railway line and the track forming the railway superstructure. The superstructure 2 located on the substructure 1 includes the ballast bed 21, the sleepers 22 placed on it and the rails 23 fixed to these.

The ground plan in figure 2 illustrates a short part of the line - only a length of two sleepers 22. We have also marked the trace line 25 on it, which is identical to the prevailing track axis. The support beam 3 supporting the sleepers 22 - and with them the entire superstructure 2 - against transverse forces, and preventing their movement in the "direction of the valley" is located along the valley-side ends of the sleepers 22. The support beam 3 extends downwards from the line level 24 representing the upper surface of the sleepers 22, and the supporting wall 4 next to it does not only extend to the base of the ballast bed 21, but preferably penetrates into the upper layer 1 la of the natural soil 11 located under it.

The supporting wall 4 ensures that the support beam 3 does not move, which also extends downwards and is constructed from at least one, but preferably from more than one layer, which layers are located on top of each other. The present example shows the deepest lower layer 41, above it the intermediate layer 42 and then the uppermost layer 43. The upper surface of this layer 43 conforms to the upper level of the ballast bed 21.

The part of the ballast bed 21 outside of the sleepers 22 is covered by the covering blanket 5 embodied as a concrete plate, into which the ends 22a of the sleepers 22 protrude. If necessary, the covering blanket 5 may also cover the support beam 3 and/or the supporting wall 4. If the water drainage conditions so demand, the bottommost layer 41 of the supporting wall 4 may be combined with a drain 7, which is constructed before the crushed stone material of the bottommost layer 41 is spread out.

Figure 3 shows a detail of the ballast bed 21. It illustrates that the crushed stone elements 21a are in a force-transmission connection with each other as a result of the adhesive material 6 applied between them. The high-strength adhesive material 6 is present at the touching surfaces; however, it does not fill up the void volume between the crushed stone elements 21 . As a result of this, the "grid" structure of the ballast bed 21 remains intact, thus enabling any water penetrating it to seep down into the substructure 1 soil. In addition, the "rough" fracture surfaces of the crushed stone elements 21a are made favourably smooth by the adhesive material 6, thereby promoting the passage of the water. Therefore, the adhesive material 6 is used in a highly fluid condition, so that the ballast bed 21, despite being preferably compacted layer-by-layer, suitably permits the adhesive material 6 to pass through it.

The significance of the structural arrangement according to the invention, and of the technology related to it, is that beside its reliably effective nature, speed and economy, it may be put to wide-ranging use for the construction of earthwork-stabilising support structures, for preventing transverse movements of curved railway lines originating from thermal force effects, and generally for increasing the load bearing capacity of all types of ballast beds, e.g. by increasing the amount of adhesive material and/or by increasing its strength.

Claims

Patent Claims

1. Structural arrangement for the stabilisation of linear earthworks, i.e. mainly railway line superstructures for the prevention of movements of the superstructure due to the effect of primarily transverse forces in relation to the direction of the trace line whilst intermittently maintaining traffic; this arrangement contains a load-bearing support structure which is preferably located outside of the railway structure gauge, and resists the movements that tend to occur at the section where the movements occur, and is characterised by that the load-bearing support structure is formed by a support beam (3) running alongside the track line, stabilising the crushed stone ballast (21) on the side of the sleepers (22) where the movements that tend to occur are directed at, a supporting wall (4) extending from the superstructure (2) towards the subsoil, installed on the side of the support beam (3) opposite to the sleepers (22) and a covering blanket (5) covering the support beam (3) and the supporting wall (4) which simultaneously embraces the ends (22a) of the sleepers (22) facing towards the support beam (3).

2. Structural arrangement according to claim 1, characterised by that the covering blanket (5) protrudes between the sleepers (22) approximately up to the line of the rail (23) located closer to the supporting structure.

3. Structural arrangement according to claim 1 or 2, characterised by that the support beam (3), the supporting wall (4) and the covering blanket (5) all contain high- strength crushed stone, preferably compacted crushed stone, as well as adhesive material (6), e.g. artificial resin, covering the stone from above and filling a minimal part of its void volume.

4. Structural arrangement according to any of claims 1-3, characterised by that the supporting wall (4) is constructed from at least one, but preferably several layers (41, 42, 43...) installed on top of each other.

5. Structural arrangement according to any of claims 1-4, characterised by that, in the case of a multi-layered supporting wall (4), the strength of the individual layers (41, 42, ...) is different, and each conforms with the size of the load on them.

6. Structural arrangement according to claim 5, characterised by that the strength of the layers (41, 42, 43...) is in proportion with the amount of adhesive material (6) according to the mass of the ballast bed (21).

7. Structural arrangement according to claim 5 or 6, characterised by that the amount of the adhesive material (6) used for the higher-strength layers (42) of the supporting wall (4) exceeds the amount of the adhesive material (6) used for the lower-strength layers (41, 43, ...).

8. Structural arrangement according to any of claims 1-7, characterised by that a drain (7) suitable for draining transmitted dampness, especially rainwater, is installed along the level of the supporting wall (4) most distant from the track line level (24).

9. Structural arrangement according to claim 8, characterised by that the drain (7) is located at the bottom of the lowest layer (41) of the supporting wall (4).

10. Structural arrangement according to claim 1, characterised by that the support beam (3) and the supporting wall (4) are seamlessly fitted to each other.

11. Structural arrangement according to claim 1, characterised by that the ends (22a) of the sleepers (22) located near to the support beam (4) are seamlessly fitted to the covering blanket (5) s.

12. Structural arrangement according to any of claims 1-11, characterised by that the upper layer (11a) of the natural soil (11) forming a part of the substructure (1) connected to the external side of the supporting wall (4) most distant from the line is treated with a strengthening additive or injection.

13. Structural arrangement according to any of claims 1-7, characterised by that the inclined side surface of the embankment is strengthened with a supplementary structure on one or more levels to stabilise the substructure, if the supporting wall (4) runs along an embankment.

14. Procedure for the stabilisation of linear earthworks, i.e. mainly railway superstructures, for the prevention of movements of the superstructure due to the effect of transverse forces in relation to the direction of the trace line, whilst intermittently maintaining traffic, during which a load-bearing support structure resistant to the forces is created on a section where movements tend to occur due to the effect of forces, e.g. thermal forces created in the railway track, preferably located outside of the railway structure gauge, either in the ballast bed itself or as a connected structure, characterised by that a support beam (3) is constructed running alongside the line on the side of the sleepers (22) forming a part of the railway superstructure (2) where the movements that tend to be created are directed at, preventing the movement of the ballast bed (21) under the sleepers (22) as well as of the sleepers (22) themselves, and that a supporting wall (4) is constructed in the earth lying up against the other side of the support beam (3), opposite the sleepers (22), and that the support beam (3) and the supporting wall (4) are covered with a covering blanket (5), and, if necessary, a drain (7) is constructed under the supporting wall (4).

15. Procedure according to claim 14, characterised by that, the supporting wall (4) along the side of the support beam (3) opposite the sleepers (22), or the support beam (3) are constructed from a single layer or from several layers (41, 42, ...) located one on top of the other.

16. Procedure according to claims 14-15, characterised by that crushed stone, preferably crushed stone of the same material and size of the superstructure ballast (21) is used for the construction of the support beam (3) and the supporting wall (4), which is spread out at the planned location after the soil excavation, then levelled out and compacted, and a highly fluid adhesive material (6) is applied to its top a part of which is permitted to seep down through the entire thickness of the crushed stone layer, and then the adhesive material (6) is left undisturbed to solidify for a bonding time complying with its nature, consistency and with the ambient temperature.

17. Procedure according to claim 16, characterised by that, when constructing the support beam (3) and the supporting wall (4), the crushed stone is spread out in one or more layers, compacted layer-by-layer: then after compaction, the adhesive material (6) is applied to the compacted crushed stone preferably throughout the entire thickness of the support beam (3) and the supporting wall (4), but at the same time the compacted void volume is maintained at an approximately unchanged level.

18. Procedure according to claim 16, characterised by that, when creating the covering blanket (5), the crushed stone forming the covering blanket (5) is generally spread out over the completed and hardened support beam (3) and supporting wall (4) reinforced with adhesive material (6) in a single layer, then adhesive material (6) is applied to it.

19. Procedure according to any of claims 14-18, characterised by that the supporting wall (4) is constructed to extend under the ground surface to such an extent that the supporting wall (4) is made from several layers (41, 42,...) created one after the other and above one another.

20. Procedure according to claim 19, characterised by that, in the case of a multi-layer supporting wall (4), when constructing the bottommost layer (41) and then, following this, when constructing the upper layers (42, 43,...), while spreading out the crushed stone of each following layer, the adhesive material (6) in the supporting wall layer under it is left to solidify.

21. Procedure according to claim 19 or 20, characterised by that, when constructing the bottommost layer (41), the drain (7) is installed before spreading out the crushed stone.

22. Procedure according to any of claims 19-20, characterised by that, in the case of a multi-layer supporting wall (4), the strength of the individual layers (41, 42, 43, ...) is adjusted to the size of the loads exerted on them.

23. Procedure according to claim 22, characterised by that at least one layer (42) of a multi-layer supporting wall (4) located at a deeper level than the support beam (3) is constructed to have greater strength than the other layers (41, 43, ..), and this greater strength is achieved by increasing the amount of adhesive material (6) to be more than in the other layers (41, 43, ...) or by using adhesive material (6) of a greater strength.

24. Procedure according to any of claims 14-23, characterised by that the "inner" side surface of the supporting wall (4) facing the track is fitted seamlessly to the support beam (3).

25. Procedure according to any of claims 14-24, characterised by that the strength of the upper layer (11a) of the natural soil (11) along the "outer" side surface of the supporting wall (4) opposite the side facing the track is increased (e.g. by adding cement).

26. Procedure according to any of claims 14-25, characterised by that the substructure (1) is supplied with a supplementary structure, if the supporting wall (4) runs along an embankment.