EP1258596B1 - Method for refurbishing a tunnel drainage system - Google Patents

Description

The present invention relates to a method for the rehabilitation of tunnel rear surface drainages, wherein a drainage line is provided below the roadway level in the tunnel and in the tunnel wall rinsing niches are provided, which extend to the drainage lines.

In order to be able to discharge the mountain waters accumulating in tunnels without damage, drainage pipes (so-called elbow drainages) are laid in the longitudinal axis of the tunnel. The pipe material (for example PVC-perforated-flexible DN 150) is embedded in filter (einkorn) concrete. The drainage pipes tend over the years and in the corresponding surrounding limestone mountains for sintering - that is, the lines "grow".

If this sintering has progressed so far that the pipe can no longer be cleaned with the usual sewer cleaning method, water leaks occur on the road.

For proper drainage of water again, the existing drainage lines must be removed and new ones introduced (e.g., PE-HD DA 140, d = 8mm, perforated).

It would of course be possible to dig through the entire tunnel to the drainage line and replace it. However, this would obviously require a considerable amount of work and time, and the traffic restrictions would be considerable.

It is an object of the present invention to provide a method for the rehabilitation of tunnel Hinterflächenentwässerungen in which the drainage lines do not have to be completely exposed.

This object is achieved by a method of the type mentioned in the present invention by attaching a core hole obliquely down to the drainage line, so that the core hole opens in the region of a rinsing niche in the drainage line that you from this rinsing niche to another rinsing a rope draws into the drainage line that introduces a drill string in the drainage line over the core hole and drills the drainage line, wherein the drill head is pulled by means of the cable so that it must remain in the drainage line, then exchanging the drill head for a rock clearer and now in the opposite direction widens the cross section, and finally pulling a new drainage line in the expanded cross section.

There are drilling systems known to drill several hundred meters and where the drill string allows a bend radius of up to 30 meters. (For example, Vermeer Navigator D16X20A from Vermeer AG in Altendorf, Switzerland.) The problem is that these devices are about 5 m long and therefore can not be brought to the drainage line via an existing flushing niche (which is usually about one meter wide). For this reason, according to the present invention, first, a core hole (e.g., having a diameter of 300 mm) is drilled obliquely to the drainage pipe. The drainage line is usually about 1 m below the road surface, the length of the oblique bore may be about 5 to 7 m (the oblique bore then meets at an angle of about 10 ° on the drainage line). The diameter of the drill rods is about 50 mm, leaving 250 mm free in the 300 mm thick core hole. This clearance is sufficient to allow the drill pipe to be guided to the height of the roadway with a bend radius of more than 30 m from the depth of the drainage pipe. Thus, the drill can be placed on the road.

As it turns out, however, it is not possible to simply re-drill the existing drainage line. The drainage pipes are rarely laid in a straight line and in bends the drill head leaves the drainage pipe. For this reason, a steel cable is first drawn into the existing drainage line (manually or with high pressure flushed) and pulled with this rope the drill head. To prevent the rope from twisting, it is connected to the drill head via a swivel. In this way you put the pilot hole (diameter for example 90 mm). As a drill head, for example, the "Trihawk rock drill head" of Vermeer AG or other specially developed drill bits.

If you have drilled so to one of the next Spülnischen, you swap the drill head against a milling head and expands in the retreat on the hole.

Preferably, the cross-section is widened twice in succession in order to destroy all tube residues of the existing drainage line.

In conventional drilling the spoil is usually rinsed out. However, it has been shown that this does not work reliably in the method according to the invention. Due to the inhomogeneity of the material (PVC and concrete) there are always sharp-edged pieces, so that the new drainage line can not be pulled in. In addition, the rinsing fluid seeps into the drainage concrete.

It is therefore provided according to a further feature of the invention that sucks out the remaining in the expanded cross-section overburden with a suction fan which is connected to a suction hose, which leads through the enlarged cross-section, out.

In practice, it has also been shown that the existing drainage lines in some places have very large curvatures or transverse offsets, which the drill string can not follow. Since the drill head is pulled through the rope along the existing drainage line, it inevitably comes to a standstill of the bore at these points. To overcome this problem, it is provided according to a further feature of the invention that previously measured the exact location of the drainage line and attaches at locations with impermissibly strong curvatures overlapping core holes to the desired position of the drainage line. In this way, the rope can be laid before the actual hole so that only allowable bends occur.

Reference to the accompanying drawings, the present invention will be explained in more detail. It shows: Fig. 1 a cross section through a tunnel; Fig. 2 schematically the installation of a Drill in the tunnel for carrying out the method according to the invention; and Fig. 3 Core holes in the region of a strong curvature of the drainage line.

The tunnel 1 is bounded below by the roadway 2 and two elevated side strips 3, 4. The drainage line 5 is below the side strip 4, about one meter below the level of the side strip and below the extreme lateral point of the elm. The drainage line 5 is surrounded by filter concrete 6. The clearance gauge is indicated by a dashed line 7.

In Fig. 2 the drainage line 5 can be seen from the side. In this Fig. Also a Spülnische 8 can be seen. Such Spülnischen 8 are usually provided every 100 m in the tunnel. In the area of a rinsing niche 8, the drainage line runs as an open channel.

Prior to performing the method of the invention, additional rinsing niches are cut from the tunnel wall to facilitate future maintenance, thereby reducing the spacing of the rinsing niches to about 50 meters.

The drainage line 5 is not always laid straight. In order to be able to determine deviations from the desired position even before the actual start of work, a special probe is pulled through the existing line and the position of the drainage line 5 is measured. This measurement is carried out by determining the distance receiver to the probe, since the depth and slope of the drainage line 5 are usually constant. From the distance and the known height of the drainage line 5, the lateral position can be calculated.

Become impermissible bends 22 (ie bends that are stronger than the minimum bending radius of the drill string), are at these points from the outside core holes 21 (eg with a diameter of 300 mm) made "man to man", so that the target position the drainage line is drilled free (s. Fig. 3 ).

The horizontal boring of the drainage line 5 takes place in each case from the rinsing niches 8. It will, depending on the distance the rinsing niches 8 and the positional accuracy of the drainage line 5, drilled sections from 150 m to 200 m per drill position (three to four niche distances).

How to get out Fig. 2 clearly recognizes, the drill 11 is much too large to introduce it into a rinsing 8 and drill from there horizontally. Therefore, an oblique core bore 9 is applied, which opens into the drainage line 5 in the region of the rinsing niche 8. The minimum bending radius of the drill pipe is about 30 m. With a diameter of the core bore 9 of 300 mm and a diameter of the drill string of 50 mm, this bending radius can easily be maintained if the length of the core bore 9 is 7 m (the drainage line 5 is one meter below the roadway level). This is in Fig. 2 to see schematically.

In order for a new line can be retracted, an insertion hole 10 is also attached to the rinsing niche 8. (This introduction bore 10 serves to draw a new line into the section of the drainage line 5 located to the right of the rinsing niche 8, whereas the drill 11 drills it into the section to the left of the rinsing niche 8. The core bore 9 and the introduction bore 10 thus belong to different refurbishment sections.)

Before starting the actual drilling a pull rope is introduced into the existing drainage line 5. This is done either manually with a pull-in spring or - if the line is not continuous - with a water high-pressure unit (1200 bar, 150 1 / s).

The drill 11 is positioned and anchored at the edge of the roadway. At the drill head, the pull rope is attached via a swivel. The pilot hole in the existing drainage line 5 can be made, for example, with a drill head with a diameter of 110 mm. About the traction cable with a mobile cable winch (tensile force in the order of 50 kN) of the drill head and thus the drill pipe in the existing drainage line. 5 held. Without the pull rope the drill head would dodge at curvatures from the existing drainage line.

When the pilot hole arrives at the final station, the drill head is replaced with a rock scraper and the cross-section is extended as required (e.g., to 180 mm). This expansion is usually carried out twice in order to destroy all the pipe residues of the existing drainage line 5.

If the required cross section has been drilled and cleared, the remaining overburden (filter concrete, pipe residues, fleece ...) is sucked out. For this purpose, a PEHD pipe is attached to a corresponding suction fan (suction power 9000 m ³ / h, for example), introduced this at the introduction hole 10 and pulled with the drill 11, and sucked the tailings with high air flow rate. The suction takes place simultaneously with the second milling.

The use of a conventional Spülbohrvefahrens is less favorable, since the open porosity of the filter concrete no purge flow can be maintained and purge additives (bentonite) would destroy the drainage effect of the filter concrete.

Then the new, pre-welded tubing (approx. 50 m) is fastened to the drill string and pulled in with the drill with the addition of a lubricant.

Finally, all newly laid sections are rinsed with 200 bar and passed through with a robot camera for inspection.

Claims (4)

1. Method for renovating a tunnel rear face drainage system, wherein a drainage pipe (5) is provided in the tunnel below the road level and rinsing recesses (8) are provided in the tunnel wall, which reach up to the drainage pipes (5), characterised in that a core bore (9) is provided obliquely downwardly to the drainage pipe (5), so the core bore (9) opens in the region of a rinsing recess into the drainage pipe, in that a cable is drawn into the drainage pipe from this rinsing recess up to another rinsing recess, in that a drill rod (11) is inserted into the drainage pipe via the core bore and the drainage pipe (5) is rebored, wherein the drill head is pulled by means of the cable, so it has to remain in the drainage pipe, in that the drill head is then exchanged for a rock scraper and the cross-section is widened in the opposite direction, and in that a new drainage pipe is finally drawn into the widened cross-section.
2. Method according to claim 1, characterised in that the cross-section is widened twice in succession, in order to destroy all the pipe remains of the existing drainage pipe.
3. Method according to claim 1 or 2, characterised in that the waste remaining in the widened cross-section is sucked out with an aspirator, which is connected to a suction hose, which is guided through the widened cross-section.
4. Method according to any one of claims 1 to 3, characterised in that the precise position of the drainage pipe is measured beforehand and overlapping core bores are brought up to the desired position of the drainage pipe at locations with unacceptably sharp bends.

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