EP0309739A2 - Method for constructing a tunnel with little earth cover under railway tracks or the like - Google Patents

Abstract

In the method for producing an underground structure, preferably a tunnel, with little earth cover under railway tracks or the like, the individual concreted structure or tunnel sections are advanced in the timed shifting process after their production. In order to prevent movements in the covering earth and the railway tracks during the digging-out of the earth at the local face and during the advancing of the tunnel sections, the rails, together with the sleepers and ballast foundation, are removed in sections. In a dug-out, flat pit is installed a covering reinforced concrete slab, onto which the ballast bed and the track skeleton are mounted again. The same procedure is followed in neighbouring areas and the reinforced concrete slab has further reinforced concrete slabs concreted onto it until the region through which a tunnel is to be driven is overlapped by a continuous concrete slab. After this concrete slab, which forms a securing means for the track, has been erected, the tunnel sections are advanced underneath said slab. <IMAGE>

Description

The invention relates to a method for producing an underground structure, preferably a tunnel, with little coverage under railroad tracks or the like, in which the first structure or tunnel section is concreted in a starting pit, this first structure or tunnel section with the soil being removed from the The front face is pushed forward in the front area, after this first building or tunnel section is advanced by a section length in the starting pit, the second building or tunnel section is created and the first section is pushed forward and the second section is pushed in and so on until the building or tunnel is completed by creating, pushing and pushing all sections.

In order to create barrier-free intersections of rail traffic routes and roads, the roads are led through tunnels under the track bodies, with the lowest possible tunnel depth in order to keep the gradients in the tunnel area as low as possible. Special problems In the construction of such road tunnels, however, it results if the track body consists, for example, of numerous adjacent track strings near the train station and the rail traffic is to be maintained with as little impairment as possible during the construction of the tunnel. If the tunnel sections are pushed under the track body with only a slight overlap according to the method described at the beginning, special measures must be taken to ensure that the overlying soil in the excavation area on the face neither collapses nor does deformation and displacement occur in the track area. By pushing the tunnel sections forward, compressive forces can be introduced into the covering layer, which can lead to bulging, shifting or warping of the covering layers, so that deformations of the track body can occur, which make undisturbed maintenance of rail traffic largely impossible.

It has already been proposed to arrange steel plates under the track body by field-wise expansion of the ballast substructure, sleepers and rails and excavation of flat construction pits, on which the ballast substructure, sleepers and rails are then reinstalled, the removal and installation taking place in sections and to connect further steel plates to the first steel plate after excavation of adjacent fields, by welding, until a steel plate covering the entire area to be tunneled results. Such a steel plate supporting the area to be tunneled has the disadvantage, however, that due to the low coefficient of friction between the sheet metal and the ground, it must be secured by special fastenings, for example by lowered piles, in order to be displaced as a result of the forces introduced into it when the tunnel sections are advanced to prevent. Even a safe from displacement However, anchoring the steel plate is not yet able to prevent deformations from occurring on the working face in the excavation area. Because of their flexibility, the steel sheets are unable to bridge a sufficiently long support length, in the protection of which it would be possible to dismantle the soil on the face, without fear of movements in the layer covering the steel plate. It has to be taken into account that, in addition, due to the maintenance of the railway traffic, considerable vertical forces act in the covering layers and thus also on the steel plate.

It is known to advance tunnel 1 sections under the track body according to the method specified at the outset, the soiling of the soil on the face being effected by so-called knife shields. In the case of such knife shields, knives lying next to one another are extended in the ridge area and bridge and support the mining area. The excavation of the soil on the face by knife shields to be inserted in front of the first tunnel section means an additional significant investment, which makes the construction of the road tunnel more expensive.

The object of the invention is therefore to provide an economical method for producing a tunnel with little coverage under track systems or the like. Of the type mentioned above, in which movements in the overlying soil and while excavating the soil on the face and pushing the tunnel sections the track systems are avoided.

According to the invention, this object is achieved in a method of the generic type in that the rails with sleepers and ballast substructure are removed in sections, that a shallow pit is excavated and one into it Field covering reinforced concrete slab is installed, that the ballast bed is then reapplied to the reinforced concrete slab and the sleepers and rails are reinstalled, that the gravel substructure and the rails and sleepers are subsequently removed in sections in adjacent fields and shallow excavation pits are excavated so that the Subsequent fields covering reinforced concrete slabs and concreted to the first reinforced concrete slab are created and the ballast bed and the sleepers and rails are reinstalled and so on until the area to be tunneled is covered with an overlap by a continuous concrete slab and that after this concrete slab, which forms a track protection, is started from the Start-up pit that is pushed forward in the tunnel sections created under the continuous concrete slab.

According to the proposal according to the invention, the section of the ballast substructure, the sleepers and the rails, as well as the concreting of the slab covering a field and the subsequent installation of the ballast, the sleepers and the rails are carried out at times when there is little or no rail traffic, so that rail traffic can be maintained by diverting to other tracks that are not covered by the section or field installation of the reinforced concrete slab. The continuous slab is erected in individual, adjacent fields, the individual field slabs being concreted onto the spreading slab. Due to the section or field-widened slab, the entire area to be tunneled is underpinned with sufficient overlap, so that after the slab has been completed, the tunnel structure can be created without fear of movements in the covering layer and in the track area. The reinforced concrete slab produced by the method according to the invention becomes so wide manufactured that it protrudes with sufficient support length into the ground on both sides of the tunnel structure. The support plate according to the invention made of reinforced concrete does not require any special anchoring in the ground, since its properties keep it immovable. The support plate derives the forces acting on it from the advance of the individual tunnel sections in areas outside the block to be advanced in each case by friction in the ground, so that there is no fear of their displacement and movement under the advance forces of the tunnel sections.

Another characteristic of the reinforced concrete slab is its flexural rigidity. It reduces the influence of the loads on the stability of the face. This allows the excavated material to be mined with steeper slopes. Furthermore, the support plate according to the invention made of reinforced concrete can bridge sufficiently long cavities so that a lowering of the covering layer and the tracks in the excavation area on the working face is not to be feared. Cavities can arise when removing obstacles, e.g. of the remains of old foundations or the like

If particularly high demands are placed on the accuracy of the height of the tunnel, a feed slide can be created for the tunnel sections in the starting pit, on which the tunnel sections are created and then pushed forward. The feed slide can be made in advance over the entire length, for example in the protection of pre-pressed pipes, or in sections.

The concrete slab installed in sections or fields can have a thickness of 20 to 30 cm. Appropriately, there are built in fields and with the progressively ver widened reinforced concrete slab connected reinforced concrete slabs made of precast reinforced concrete slabs laid next to each other, the joints or gaps for connecting the precast reinforced concrete slabs being concreted.

Once the reinforced concrete slab underlining the track systems and covering the area to be tunneled has been created, the construction of the tunnel structure begins. First of all, a start-up or start-up pit is built and the first tunnel section on slideways is created in it. In order to be able to advance this first section of the tunnel, the starting excavation must be provided with corresponding abutments on the back. The first tunnel section is then advanced on a previously created slideway, with the earth on the face being mined and removed using conventional excavation equipment.

According to the method according to the invention, the building or tunnel sections can be advanced in such a way that their upper cover plates are supported directly on the installed reinforced concrete plate which is at rest. In this method for reducing friction, a steel plate is expediently fastened to the cover plate of the building or tunnel section to be advanced. Since the tunnel section to be advanced is supported directly on the underside of the reinforced concrete slab, there is no need to fear lifting and settling of the reinforced concrete slab.

According to another advantageous embodiment, it is provided that the cover plate of the building or tunnel section to be advanced is provided with sliding pieces or rails, by means of which it is supported on the reinforced concrete plate. The sliders or slide rails, which can extend at a distance from each other in the feed direction, form as it were Friction reducing skids. The gaps between the sliders or skids can later be pressed out with concrete or another suitable filler.

According to a further advantageous embodiment, it is provided that a load-transmitting layer of essentially shear-resistant and stable material is introduced before laying the reinforced concrete slabs in the shallow excavation pit, which is cut when pushed through by the ridge-side steel cutting edge of the first structural section. This load-transmitting layer thus extends below the cutting edge of the first section to be advanced, the shear surface forming a sliding surface. The layer is so stable that the underside of the reinforced concrete slab remains covered.

A suitable material is, for example, a sand enriched with concrete, ie an artificially created layer with clay or clay properties that adheres to the underside of the reinforced concrete slab. The cut layer forms a base layer between the concrete slab and the cover slabs of the advanced sections, so that no cavities can be formed which would have to be filled in later. Furthermore, a friction-reducing sliding joint is formed between the cut layer and the sections to be advanced.

• Fig. 1 eine Draufsicht auf die zu untertunnelnde Gleisanlage mit im Bau befindlichem Tunnel,
• Fig. 2 einen Längsschnitt durch die Gleisanlage nach Fig. 1 mit im Bau befindlichem Tunnel,
• Fig. 3 einen Querschnitt durch die Startbaugrube,
• Fig. 4 einen Querschnitt durch das im Bau befindliche Tunnelbauwerk im Bereich des Bahndamms,
• Fig. 5 einen Querschnitt durch eine der drei Vorschubbahnen nach den Fig. 1 und 2,
• Fig. 6 einen Längsschnitt durch das Tunnelbauwerk im Bereich des vogeschobenen vorderen Abschnitts, und
• Fig. 7 einen Querschnitt durch den fertigen Tunnel.

An embodiment of the invention is explained below with reference to the drawing. In this shows

• 1 is a plan view of the track system to be tunneled with a tunnel under construction,
• 2 shows a longitudinal section through the track system according to FIG. 1 with a tunnel under construction,
• 3 shows a cross section through the starting pit,
• 4 shows a cross section through the tunnel structure under construction in the area of the railway embankment,
• 5 shows a cross section through one of the three feed tracks according to FIGS. 1 and 2,
• Fig. 6 is a longitudinal section through the tunnel structure in the area of the advanced portion, and
• Fig. 7 shows a cross section through the finished tunnel.

As can be seen from FIG. 1, numerous tracks 1 are arranged closely next to one another on the terrain to be tunneled. In order to manufacture and advance the individual tunnel sections 2, 3, 4 which form the tunnel to be created, an excavation pit 5 is created at a distance from the track system. On the back of the excavation pit is provided with a concrete abutment 6, which absorbs the feed forces during the advancement of the tunnel sections 2, 3, 4.

Before the tunneling of the area of the track system begins, a concrete slab 7 is installed under the tracks as a track safety device. This concrete slab 7 is indicated by dashed lines in FIG. 1 and has upper and lower serrated edges. For the production of this concrete slab, the rails, sleepers and the ballast substructure are removed in sections and in this section there is a flat construction pit excavated and in this then prefabricated reinforced concrete slabs 8 are installed in the manner shown in FIG. 1. The gaps or joints 9 between these pre-cast concrete slabs 8 are then concreted, so that a continuous concrete slab has been formed in the section. The ballast substructure, sleepers and rails are then reapplied to this concrete slab so that train traffic can be resumed. Then the rails, sleepers and the ballast substructure are removed in a neighboring section and a shallow excavation pit is excavated in a corresponding manner and a concrete slab made of precast reinforced concrete slabs is built in it, which is concreted onto the first slab. Then the ballast substructure, sleepers and rails are reinstalled. Progressively, the continuous concrete slab 7 is erected section by section or by field under the entire area of the track system to be tunneled. Once this continuous concrete slab 7 has been completed, the actual tunneling work can begin. For this purpose, three strip foundations 10 are built in the starting pit 5, each of which is provided with a longitudinal slide rail 11 made of steel. The first tunnel section 2 is then built on these strip foundations. After completion of this tunnel section 2 with an open front side, it is pushed forward by feed presses, the earth being excavated on the working face in the manner shown in FIG. 6 by excavators and driven off by trucks.

Before the individual tunnel sections are pushed forward, 10 steel tubes 12 are pressed under the area to be tunneled in extension of the strip foundations, which serve to create the later slideways for the tunnel sections to be pushed forward. To push through these pipes 12 are on the opposite side of the starting pit 5 to tunneling track system construction pits 13,14,15 erected. In accordance with the shaping step of the feed, the pressed-through steel tubes 12 are cut open in their upper region in the manner shown in FIG. 5 and filled with reinforced concrete. The slide rail itself forms a precast reinforced concrete part 16 clad in sheet steel with a rectangular profile. To improve the sliding properties, the individual tunnel sections to be pushed forward are provided with a sliding layer made of sheet steel on their underside.

As can be seen in particular from FIG. 6, the individual tunnel sections are pushed through below the previously installed concrete slab 7, which serves to secure the track. For advancing the individual tunnel sections are provided between these intermediate pressing stations 18 so that the feed forces are not too great.

As can also be seen from FIG. 6, the first tunnel section to be pushed through is provided at its front end with a hood shield with steel cutting edges, an intermediate stage being provided.

The type of creation and pushing of the individual tunnel sections is known per se, can be seen from the drawing and therefore need not be explained in more detail.

Claims (7)

1. A method for producing an underground structure, preferably a tunnel, with a slight overlap under track systems or the like, in which the first structure or tunnel section is concreted in a starting pit, this first structure or tunnel section with the removal of the soil on the face in the front area is pushed forward, after this first building or tunnel section has been advanced by a section length in the starting pit, the second building or tunnel section is built and the first section is pushed forward and the second section is pushed in and so on until the building or tunnel is completed by building , Pushing and pushing all sections,
characterized,
that the rails with sleepers and ballast substructure are removed in sections,
that a shallow pit is excavated and a reinforced concrete slab covering a field corresponding to the section is installed in it,
that the ballast bed is then reapplied to the reinforced concrete slab and the sleepers and rails are reinstalled,
that the gravel substructure, the rails and sleepers are subsequently removed in sections and shallow excavation pits are excavated in adjacent fields,
that in these covering the adjoining fields and concreted to the first reinforced concrete slab, the ballast bed, the rails and sleepers are reinstalled and so on until the area to be tunneled is covered with an overlap by a continuous concrete slab, and
that after the construction of this concrete slab, which forms a track protection, starting from the starting pit, the building or tunnel sections created in it are advanced under the continuous concrete slab. 2. The method according to claim 1, characterized in that the field-wise installed reinforced concrete slabs are made of precast reinforced concrete slabs laid next to one another with joints or gaps concreted out. 3. The method according to claim 1 or 2, characterized in that a feed slide is created in the starting pit, the tunnel sections are concreted on this feed slide and then advanced, the Feed slide is created in advance over the entire length of the tunnel or is built in sections. 4. The method according to any one of claims 1-3, characterized in that the building or tunnel sections are advanced such that their cover plates are supported directly on the reinforced concrete slab at rest. 5. The method according to claim 4, characterized in that a steel plate is attached to reduce friction on the cover plate of the building or tunnel section to be advanced. 6. The method according to any one of claims 1-3, characterized in that the cover plate of the building or tunnel section to be advanced is provided with sliders or slide rails which are supported on the reinforced concrete plate. 7. The method according to any one of claims 1-3, characterized in that a load-transmitting layer of substantially shear and stable material is introduced before laying the reinforced concrete slab in the shallow excavation pit, which is cut when pushed through by the ridge-side steel cutting edge of the first building section .

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