CA2265104A1

CA2265104A1 - Drainage system for tunnels

Info

Publication number: CA2265104A1
Application number: CA002265104A
Authority: CA
Inventors: Jochen Kasselmann
Original assignee: Fosroc International Ltd
Current assignee: Individual
Priority date: 1997-09-04
Filing date: 1999-03-09
Publication date: 2000-09-09
Also published as: EP1035300B1; DE19738488A1; ATE249570T1; CH691697A5; EP1035300A1

Abstract

A tunnel drainage system comprises a plurality of plastic parts connected together in the form of: shaped lengths, each with an arched profile having a ribbed surface contour and an angled substantially flat lateral section on each side; and a plurality of molded parts for coupling the shaped lengths to each other, and to one or more main collection conduits. The shaped lengths, and coupling parts are made of from high impact and tear resistance high density polyethylene (HDPE) preferably between about 0.8 - 1.5 mm thick using a deep draw process in which films or boards of HDPE are drawn by vacuum over a positive form. Single spaced ribs, typically wider than the ribs of the ribbed surface contour of the shaped lengths, may extend across the shaped lengths including the otherwise substantially flat lateral sections. The coupling parts and collection conduit may have ribs similar to those of the shaped lengths. The system of the invention maintains a proper, sealed, long-life water passage for draining water from a tunnel even when covered with shortcrete used in tunnel construction.

Description

DRAINAGE SYSTEM FOR TUNNELS
BACKGROUND AND SUMMARY OF THE INVENTION
The invention concerns a process for the manufacture of a drainage system components for tunnels, and for tunnel drainage systems. The invention comprises or consists of multiple plastic parts for connection to each other, in the form of shaped lengths with an arched profile made of plastic having a ribbed surface contour and angled lateral sections on both sides, as well as moulded parts suitable for coupling and attachment, which are required in tunnel constructions in order to collect and drain water. The invention is particularly applicable to collection of water forced through the rock surface of 1p the tunnel, and transports the water in a controlled manner under the llnish covering, especially shotcrete, to main collection conduits. The invention is also concerned with a drainage system for surface water emerging under pressure out of the tunnel rock walls under the finish covering, especially concrete, particularly in tunnel constructions. The invention preferably comprises or consists of arched shaped lengths with angled lateral parts on both sides, and a surface contour having ribs running perpendicular to the longitudinal axis and molded parts that ensure the connection of either confluent shaped lengths or the main collection conduit through overlapping, or the attachment of collection hoods, for instance to anchor heads.
EP-A1 -0 648 916 discloses shaped lengths of flexible sealing material, with which joints and gaps remaining in concrete cladding are covered over, in order to collect the water emerging therefrom in order to transport it away in a controlled manner.
The shaped lengths comprise an arched middle part and lateral parts, capable of being bent down, molded onto the arched middle. The lateral parts are provided with contouring in order to improve adhesion to the concrete parts or other cladding elements of the tunnel. What is disadvantageous is that these known shaped lengths can only be used for sealing or additional sealing of gaps in finished concrete parts or similar cladding elements and are applied to these from the outside. Since they probably are of flexible sealing material, and especially rubber, they would be so damaged by the covering shotcrete or thereby compressed that the water would no longer be able to flaw through them.
Furthermore, attachment to the rock surface through adhesion is not, in practice, possible.
CH-PS 479 777 dated 1968 describes an open channel having laterally molded edge strips to enable a better attachment to the rock surface. The channel also posses a stiffening wire which, being such, allows bending, that is flat compression, of the channel.
The channel Is of a PVC film, and the stiffening wire is also provided with a corresponding PVC coating. These known open channels allow a certain degree of adaptation to the rock surface, although it has become apparent that the PVC material in use does not allow covering with shotcrete, Rather, here too, the channel is damaged to the extent that reliable removal of the water is no longer assured.
USP 3,699,684 reveals drainage pipes made of flexible material, whereby the pipes are placed into previously prepared incisions or channels, in order to transport away the water collected in them. Stiffening rings or wires are set into the material at intervals, so that they are best suited to horizontal drainage, since inlet openings are provided at intervals between the stiffening rings, through which the water can enter.
This full round type of pipe is not suitable for drainage to be undertaken largely in a vertical attitude.
Even if this pipe were simply to be halved, connection with or attachment to, the rock surface would not be possible. The openings provided at intervals between the stiffening rings would also prove to be disadvantageous in that case.
USPS 4,380,042 discloses a drainage pipe that is also intended for horizontal drainage and which has a stiffening base part in which. there are openings in order immediately to conduct away the water leeching into the channel or drain. In this case, also, a ribbed surtace profile is provided, comprising wave troughs and crests arranged in equal separation from each other. There is a folded edge provided here, although only in order to facilitate connection to the base part, which provides the required stiffening. The entire body is of a -flexible material and is therefore, once again, not suited for covering with shotcrete when installed on the rock surface.

The European patent application 96 810 239.2, in which the texts referred to earlier here are cited as the state of the art, describes a drainage system of a suitably flexible shaped length and associated molded pans, whereby bath the shaped lengths and the molded parts have a ribbed surface contour in the junction area and can therefore easily be joined to each other. The shaped lengths are equipped on both sides with angled lateral parts to enable connection with the rock surface, and angled folds at the end into which a sealant material is injected to prevent the egress of water. Here, too, the shaped lengths and the molded parts are made of a flexible material (i.e. plastic), so that they can be placed at the water exit points suitably bent, although they are damaged and thereby rendered unusable if the drainage system is covered with shotcrete, whereby account must be taken of the fact that, in order to make it adhere to the rock surface, the shotcrete has tv be applied under appropriate pressure. Even the ribbed surface contouring is not sufficient to prevent destruction of the molded parts or shaped lengths. Also disadvantageous are the facts that no effective covering over of the water exit locations in the region of the anchor caps is possible, and that angling is difficult despite wedge-shaped notches provided for that purpose. Furthermore, as previously mentioned, the material is a flexible plastic, which does not permit manufacture of the drainage system in a sufficiently stable form.
The invention creates a drainage system in the form of a collection and conduction system that is simple to assemble and can be covered over with shotcrete while ensuring faultless transport of water. This is accomplished by utilizing films or thin-walled boards made from high density polyethylene (HDPE) of high impact resistance and tear resistance with a width chosen to be slightly greater than the subsequent shaped lengths.
The boards are heated for deep drawing, and are drawn over a positive form by application of a vacuum, and are so molded that, over substantially the entire length in the arched region, the same surtace contouring with smooth lateral parts is produced. Deep drawing of plastic parts is conventional per se, as shown by U S Patent 4,818,465.
By utilizing a manufacturing process as described above, it is possible to make an arched shaped length that is designed, purely by virtue of its shape and the material used to manufacture it, so that it can be covered over without difficulty using shotcrete after its installation on the rock surface. The very dense PE material with its high level of impact resistance protect against the more or less fine quartz particles contained in the shotcrete, without the possibility of any significant damage arising, so that, in any event, the hollow space through which (after covering with shotcrete) the surface water or the water emerging from the rock surface can be transported without causing any damage to the tunnel lining, remains intact. Of further advantage is the fact that., due to the surface contouring being substantially the same over the entire length, a secure overlap, and therefore linking with the molded parts, is possible. The molded parts also possess substantially the same surface contour in the joint region. An identical profile of this kind can be reliably manufactured using the deep drawing process so that, through the formation of the smooth lateral parts, that different from the form of the arched area, a sealing surface is created that is generally adequate to ensure that the water flows through the arched area and does not escape laterally. Solely in the case of special ground or rock surface areas might it be necessary to effect additional sealing by the use of sealing materials.
In a suitable embodiment of the invention, it is intended that molded parts shaped to fit the anchor heads or attaching points of the shaped lengths are deep drawn from films or thin-walled boards, so that they are given substantially the same or a slightly larger than contour, as the shaped lengths in the later joining regions. The molded parts, which secure only relatively short sections, are also preferably made from substantially the same material and in substantially the same manner, so that even with a disadvantageously applied covering of shotcrete, continuous drainage is assured. Profiling in the joining region makes possible a safe coupling to the relevant part of the shaped length, and without the need for any additional sealing material. Rather, by overlapping of the shaped parts provided with contouring and of the shaped lengths, a form of labyrinth seat is achieved that is adequate for this application. Through the process of manufacture as deep drawn parts, a consistent profiling and therefore a sure connection with the shaped lengths is assured.

A particularly advantageous embodiment of the molded parts, kept to precise specifications, is possible if films or boards of a thickness between about 4.8 and 1.5 mm (and all narrower ranges within that broad range) and preferably about 1.2 mm, are used for the shaped lengths and the molded parts. With about 1 rnm and thicker films (and 5 boards, too,) deep drawing is possible, as well as precise profiling when deep drawing, so that the connection of the individual parts of the drainage system is sure, and so that there is a sufficient wall thickness in all areas of the molded parts and shaped lengths.
It has been shown that not every PE material is suitable for the manufacture of appropriately advantageous drainage systems according to the invention. The invention provides for the shaped lengths and molded parts to be manufactured out of a HDPE with a formulation corresponding to the plastic used for refuse bins. This material has a very high density and high impact resistance. sealing capability and other values, which, as with refuse bins, ensure adequate service life even under heavy loading.
With the help of the process according to the invention, a drainage system is made that comprises or consists of multiple parts, the drainage system itself is to be protected, and apart from the shaped lengths with angled lateral parts on both sides, molded parts are also provided that have ribs in the connecting region which are substantially the same as or correspond to those of the shaped lengths. The shaped lengths themselves comprise or consist of an arched middle section with sine wave-shaped ribs and the lateral parts running at an angle thereto it without any contouring. The shaped lengths may be formed from a single piece from HDPE of a special formulation with a high impact resistance, and have single ribs at a predetermined distance from each other and each running through to the edges of the shaped length. A shaped length of this type possesses the necessary stability and impact resistance for the application of shotcrete thereto, and can be securely attached in the edge region to the rock surface with nails, anchors or similar structures, while simultaneously providing a seal because the lateral parts have a substantially flat, smooth surface. The lengths can be installed bent according to the prevailing conditions, since single ribs running through to the edge are provided at a substantially equal distance from each other, which permits bending to either side. It is conceivable that the molded parts could also possess corresponding single ribs, although this is not necessary in general, if the single ribs had the relevant dimensions, because then a lack of seal in the upper region of the flat lateral parts would not be harmful.
A further embodiment of the invention comprises one in which the continuous single ribs are formed to be correspondingly substantially as broad as, or broader than, the other ribs. This means that overlapping (in order to connect neighboring drain parts) is possible without difficulty, because in the important area of connection with the rock wall substantially flat parts are present which do not pose a problem for correspondingly proud-standing single ribs. On the other hand, bending in practically all directions is possible, and therefore adaptation to the water emerging from various sites.
Particularly advantageous in this respect is when the single ribs have the width of two positive ribs and one negative rib, since then the necessary bending is possible and, at the same time, a corresponding overlap is provided since one single rib overlaps two positive ribs without presenting any joint problems.
The formation of molded parts in the connection region so that an overlap or connection with the neighboring shaped length is achieved is preferably made possible by providing the molded parts with coupling ribs corresponding to the ribs of the shaped lengths - that is, ribs that have slightly larger dimensions so that they can be placed over the ribs of the neighboring shaped length. However, the coupling ribs should not be too large, since then the necessary labyrinth seal could be impaired.
Of particular importance to the function of the invention is catching water that emerges in the region of anchor heads. Since the anchors or the holes drilled to accept them may possibly intersect several water-conducting slip planes and fissures, wafer leakage there is a particular problem. Therefore, the invention allows for the molded anchor parts associated with the anchor heads to have a cap that accepts the anchor end, anchor nut, and possibly the domed plate. In this way, a molded anchor part can be placed over the entire anchor head in order to seal this area and to ensure that the water emerging there is transported through the drainage system. This is particularly so when the molded anchor part of the domed plate has a rectangular shape and a receptive sealing bead is formed around 'rt. The sealing bead simply ensures that the emerging water does not seek other routes, but is collected by the molded anchor part and transported away through the drainage system.
In this regard, it is desirable if the sealing bead is produced through shaping, or through tapering of the bent-over edges, an approximate linear contact with the rock surtace is produced. In this way, a seating bead in the proper sense, that is, an additional molded part, is not required at all. Rather, the entire molded part - the molded anchor part in this case - simultaneously provides the seating region, thus allowing a simpler manufacturing processes.
The rock surtace might comprise protruding parts in the area of the relatively small molded anchor parts. In order to achieve adaptation to the rock surface, the invention provides for the molded anchor parts to have molded ribs substantially the same as, or similar and running parallel to, the ribs of the shaped lengths. In this way, the entire molded anchor part can be easily bent and so adapted to the existing shape of the rock surface.
The prior art typically uses a main collection conduit, comprising a round pipe, probably also made of plastic. This round pipe can only be adapted to a limited extent to the course of the rock surface, which is not usually straight. This is helped by the embodiment of the invention in that the main collection conduit is made of ribbed piping such that its ribs are formed so that they correspond to the ribs of the shaped lengths.
This means that the drainage system can be easily connected to the main collection conduit while, at the same time allowing a predetermined course of the main collection conduit along the rock surface.
An advantageous possibility for the connection of the drainage system to the main collection conduit is also provided for if this is made as a polygonal or preferably rectangular-section pipe, although a main collection conduit of this form naturally does not fit as well to the contours of the rock surface as the previously described ribbed pipe.

However, such a rectangular-section pipe can have advantages for particular application purposes.
The invention distinguishes itself in particular by providing a drainage system that can be used to particular advantage where shotcrete has to be applied for stabilization of the rock surface. Even under this problematic coating, maintenance of the effectiveness of the drainage system employed is assured since it is manufactured from the particular PE
material described, so that when the shotcrete is applied, no particular precautions need to be taken. This applies both to the shaped lengths and to the molded parts.
Installation of the shaped lengths is significantly simplified by the fact that the lateral parts are simply nailed onto the rock wall in order, at the same time, to produce the necessary seal, because the lateral parts have flat surfaces and so water cannot emerge therefrom. The molded parts can, through appropriate formation, easily be attached to the ground or rock wall as well as to the relevant shaped lengths, since, at least in the coupling area they possess corresponding ribs. Particularly advantageous are both the connection of the shaped lengths with the individual molded parts (particularly the molded anchor parts) as well as with the main collection conduit, so that it can be guaranteed with the necessary degree of certainty that pressurized water will not endanger the tunnel wall, even after a long service life.
According to one aspect of the present invention there is provided a method of manufacturing a component of a drainage system comprising: a plurality of plastic parts connected together in the form of shaped lengths, with an arched profile having a ribbed surface contour and an angled lateral section on each side of the arched profile; and a plurality of molded parts for coupling the shaped lengths to each other and to main collection conduits; said method comprising: (a) selecting films or thin-walled boards made from high impact and tear resistance high density polyethylene and having a width slightly greater than the desired width of shaped lengths to be formed therefrom; (b) heating the films or boards from (a) to a conventional temperature suitable for deep drawing; and (c) by the application of a conventional level of vacuum, deep drawing the heated films or boards from (b) over a positive form to produce a shaped length having over substantially the entire length thereof an arched profile with two sides, with a ribbed surface contour, and an angled lateral section on each side of the arched profile. The method may further comprise using the shaped length from (c) with other shaped lengths and molded coupling parts to provide a tunnel water drainage system.
The method may also further comprise: (d) selecting films or thin-walled boards made from high impact and tear resistance high density polyethylene and having dimensions corresponding to molded coupling parts to be formed therefrom; (e) heating the films or boards from (d) to a temperature suitable for deep drawing; and (f) by the application of vacuum, deep drawing the heated films or boards from (e) over a positive form to produce a molded coupling part having a configuration with substantially the same, or slightly larger, contour as the portions of a shaped length to which the molded coupling part is to be connected; and connecting the shaped length from (c) and the molded coupling part from {f), together to provide a tunnel water drainage system. In the method (a) and (d) may be practiced by selecting a film or board having a thickness between about 0.8 - 1.5 rnrn. {e. g. by selecting a film or hoard from a high density polyethylene used to make refuse bins and having a thickness of about 1.2 mm.) According to another aspect of the invention there is provided a drainage system for tunnels having rock walls, comprising: a plurality of shaped lengths, each with: an arched profile having first and second sides, a plurality of ribs defining a ribbed surface contour, and a substantially flat angled lateral section on each of the first and sides; the shaped lengths capable of transporting water in a substantially leak-free manner in a tunnel environment; at least one main collection conduit for transporting water from the shaped lengths in or from a tunnel; and a plurality of molded parts coupling the shaped lengths to each other and to the at least one main collection conduit; and wherein the shaped lengths each comprise a substantially single piece of high impact and tear resistance high density polyethylene and having a plurality of spaced single ribs extending across the arched profile and substantially flat angled lateral sections. Preferably, the plurality of molded parts are also made of high impact and tear resistance high density polyethylene, such as of the type used to make refuse bins. Preferably the high impact and tear resistance high density polyethylene has a thickness of between about 0.8 - 1.5 mm.
Preferably the single ribs are substantially as wide as, or wider than, the ribs of the ribbed surface contour. Also preferably the ribbed surface contour comprises alternating positive and negative ribs; and wherein the single ribs have a width substantially equal to two of the positive ribs and one of the negative ribs. Also, the coupling parts typically comprise coupling ribs in connecting regions thereof which correspond to the ribs of the ribbed surface contour of the shaped lengths. The drainage system also further comprises anchor heads, including an anchor bolt end, anchor nut, and domed plate, provided in the tunnel rock; and wherein the coupling parts include caps that accept the anchor heads, and are connected to the shaped lengths. Typically the caps have a substantially square configuration corresponding to that of the domed plate, and a sealing bead formed therearound far engaging the rock, and the caps have molded ribs substantially the same as the ribs of the ribbed surface contour of the shaped lengths. The sealing bead may be provided by shaping or tapering of a downward angled edge of a the cap.
In the preferred embodiment the at least one main collection conduit comprises an enclosed ribbed pipe having a plurality of ribs substantially corresponding to the ribs of the ribbed surtace contour of the shaped lengths. Also, the at least one main collection conduit preferably has a substantially polygonal (e. g. rectangular) cross-section.
It is the primary object of the present invention to provide a simple yet effective method of making component parts for a tunnel drainage system, and an improved tunnel drainage system. This and other objects of the invention will become clear from an inspection of the detailed description of the invention, and from the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGURE 1 is a schematic simplified representation of a drainage system according to the invention attached to a rock wall;
FIGURE 2 is a top plan view of a shaped length of the system of the invention;

FIGURE 3 is a partial cross-section in the area of the middle section, of a shaped length according to one embodiment of the invention;
FIGURE 4 is a plan view of an exemplary molded anchor part according to the invention;
FIGURE 5 is a longitudinal cross-section of a molded anchor part according to the invention;
FIGURE 6 is a schematic cross-section of a drainage system installed on a rock surface, or a shaped length in the drainage system, according to the invention.
DETAILED DESCRIPTION OF THE DRAWINGS
FIGURE 1 shows a drainage system 1 mounted on a rock wall 2, so that the water emerging from individual sections of the rock wall 2 can be reliably transported to the main collection conduit 4 laid on the tunnel floor 3. The drainage system 1 comprises or consists of shaped lengths 5 with surface contouring 8 and smooth lateral parts 6, 7. It can be seen that the lateral parts 6, 7 are attached with nails 16, 17, or like fasteners, to the rock wall 2. It is not necessary to specify relevant points on the lateral parts 6, 7, although this may simplify installation, especially under difficult conditions.
The surface contouring 8 comprises or consists of wave-shaped ribs 9, 10, and 11.
The ribs 9, 10, 11 comprise substantially regularly shaped waves, which simpl'rfy installation, and simultaneously improve the stability and simplify application of shotcrete, because they represent a form of adhesion zone for the shotcrete. This multiple effect is particularly advantageous in that in the area of the relatively narrow lateral parts 6, 7 no adhesion is provided, or at best only through the nails 1fi, 17, The shaped lengths 5, 5', 5" are connected by the molded parts 1 Z, 13, 14 to each other or to appropriate other parts. Thus the molded part 12 serves to connect shaped length 5 to the main collection conduit 4 (aid on the tunnel floor 3, while the substantially Y-shaped piece -- that is the molded part 13 -- produces a branch so that the shaped lengths 5' and 5" can run to the relevant anchor heads 15 at an angle to the central shaped length 5. The anchor heads 15 are considered in more detail later on, and it will only be mentioned here that the relevant anchor head 15 is fully covered by the molded anchor part 14.
FIGURE 2 is a plan view of part of a shaped length 5 which shows that only the middle section 18 is provided with ribs 9, 10, 11. These ribs 9, 10, 11 are distributed evenly over substantially the entire length, and only at intervals are single ribs 21 provided that run right across to the edges 19, 20 of the shaped length 5. These single ribs 21 enable or simplify curved installation of the shaped length 5 on the rock wall 2, as is suggested FIGURE 1.
V1lhile the middle section 18 has ribs 9, 10, 11 and single ribs 21, in the area of the lateral parts 6, 7, there are no ribs, or only the continuous single ribs 2 1.
This flat shape ensures that installation of the shaped lengths 5 is possible without any additional measures, i.e, special sealing measures. The narrow single ribs 21 do not represent a hindrance, so that it can otherwise be ensured with suitable measures that these contour ribs do not interrupt the seal zone.
FIGURE 3 shows how the single ribs 21 can be formed differently than in FIGURE
2. Here an arch-shaped single rib 21 is illustrated which has the width of two positive ribs 22 and one negative rib 23. The single rib 21 can also be formed with a relatively flat shape, so that in both cases when the shaped length 5 is laid on the connecting region 25 of molded parts 12, 13, 14, overlapping action is not hindered. When the connecting region 25 is laid on the shaped lengths 5, there may be a slight hindrance under certain circumstances which, however, can be compensated for by providing a sufficiently broad connecting region 25.
FIGURES 4 and 5 show a molded anchor part 14 in plan view and in cross-section, respectively, wherein it is clear that coupling ribs 26 are provided in the connecting region 25, facilitating connection with adjoining shaped lengths 5 because the parts are made slightly broader.
In this design of the molded anchor part 14, it is important that it covers the entire anchor as far as possible, as is made clear in FIGURE 5. The anchor bolt 27 fastened into the earth lies with the anchor end 28 and the anchor nut 29 protruding above the rock wall 2, so that the cap 31 covers not only this region, but also the entire domed plate 30, which allows for effective tightening of the anchor or the anchor bolt 27 using the anchor nut 29.
FIGURE 5 shows that, in the region of the edge 34, either a sealing bead 32 can be included or that a seal can be achieved through tapering of the edging 34. so that water cannot escape, but rather is caught in the molded anchor part 14 and is then transported through the connecting region 25.
FIGURE 4 shows a special embodiment with molded ribs 33. 33 formed so that the molded anchor part can be bent according to the shape of the rock wall 2, to provide a better seal.
FIGURE 6 shows a drain 1 installed on a rock wall 2, wherein it is clear that the d rains of the invention cover, by way of example, water-conducting fissures 36 in order to collect the water emerging from them and to transport it safely under the shotcrete [not shown]. Identifiable here are the fixing nails 37 that are inserted through lateral parts 6, 7 into the rock 2 and thus enable effective attachment. In FIGURE 1 these fixing nails are identified as 16 and 17; these attachment means (e.g. nails 16, 17) can alternatively be small anchors or the like.
FIGURE 6 makes it clear that the lateral pal-is 6, 7 can possess a raised edge 38, in order to introduce sealing material 39, or a turned down edge 40, which is generally adequate to concentrate the entire water flow in the region of the hollow space 41. This may possibly also be influenced in that the fixing nails 37 are not only inserted, as shown here, centrally in the lateral parts 6, 7, but offset close to the middle section 18 or to the edges 38, 40.
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A method of manufacturing a component of a drainage system comprising: a plurality of plastic parts connected together in the form of shaped lengths, with an arched profile having a ribbed surface contour and an angled lateral section on each side of the arched profile; and a plurality of molded parts for coupling the shaped lengths to each other and to main collection conduits; said method comprising:
(a) selecting films or thin-walled boards made from high impact and tear resistance high density polyethylene and having a width slightly greater than the desired width of shaped lengths to be formed therefrom;
(b) heating the films or boards from (a) to a temperature suitable for deep drawing;
and (c) by the application of vacuum, deep drawing the heated films or boards from (b) over a positive form to produce a shaped length having over substantially the entire length thereof an arched profile with two sides, with a ribbed surface contour, and an angled lateral section on each side of the arched profile.

2. A method as recited in claim 1 further comprising (d) using the shaped length from (c) with other shaped lengths and molded coupling parts to provide a tunnel water drainage system.

3. A method as recited in claim 1 further comprising (d) selecting films or thin-walled boards made from high impact and tear resistance high density polyethylene and having dimensions corresponding to molded coupling parts to be formed therefrom; (e) heating the films or boards from (d) to a temperature suitable for deep drawing; and (f) by the application of vacuum, deep drawing the heated films or boards from (e) over a positive form to produce a molded coupling part having a configuration with substantially the same, or slightly larger, contour as the portions of a shaped length to which the molded coupling part is to be connected.

4. A method as recited in claim 3 connecting the shaped length from (c) and the molded coupling part from (f), together to provide a tunnel water drainage system.

5. A method as recited in claim 1 wherein (a) is practiced by selecting a film or board having a thickness between about 0.8 - 1.5 mm.

6. A method as recited in claim 3 wherein (a) and (d) are practiced by selecting a film or board having a thickness between about 0.8 - 1.5 mm.

7. A method as recited in claim 6 wherein (a) and (d) are practiced by selecting a film or board from a high density polyethylene used to make refuse bins and having a thickness of about 1.2 mm.

8. A drainage system for tunnels having rock walls, comprising:
a plurality of shaped lengths, each with: an arched profile having first and second sides, a plurality of ribs defining a ribbed surface contour, and a substantially flat angled lateral section on each of said first and sides; said shaped lengths capable of transporting water in a substantially leak-free manner in a tunnel environment;
at least one main collection conduit for transporting water from said shaped lengths in or from a tunnel; and a plurality of molded parts coupling said shaped lengths to each other and to said at least one main collection conduit; and wherein said shaped lengths each comprise a substantially single piece of high impact and tear resistance high density polyethylene and having a plurality of spaced single ribs extending across said arched profile and substantially flat angled lateral sections.

9. A drainage system as recited in claim 8 wherein said plurality of molded parts are also made of high impact and tear resistance high density polyethylene.

10. A drainage system as recited in claim B wherein said high impact and tear resistance high density polyethylene is of the type used to make refuse bins.

11. A drainage system as recited in claim 10 wherein said high impact and tear resistance high density polyethylene has a thickness of between about 0.8 -1.5 mm.

12. A drainage system as recited in claim 8 wherein said single ribs are substantially as wide as, or wider than, said ribs of said ribbed surface contour.

13. A drainage system as recited in claim 12 wherein said ribbed surface contour comprises alternating positive and negative ribs; and wherein said single ribs have a width substantially equal to two of said positive ribs and one of said negative ribs.

14. A drainage system as recited in claim 8 wherein said coupling parts comprise coupling ribs in connecting regions thereof which correspond to said ribs of said ribbed surface contour of said shaped lengths.

15. A drainage system as recited in claim 8 further comprising anchor heads, including an anchor bolt end, anchor nut, and domed plate, provided in the tunnel rock;
and wherein said coupling parts include caps that accept said anchor heads, and are connected to said shaped lengths.

16. A drainage system as recited in claim 15 wherein caps have a substantially square configuration corresponding to that of said domed plate, and a sealing bead formed therearound for engaging the rock.

17. A drainage system as recited in claim 15 wherein said caps have molded ribs substantially the same as said ribs of said ribbed surface contour of said shaped lengths.

18. A drainage system as recited in claim 16 wherein said sealing bead is provided by shaping or tapering of a downward angled edge of a said cap.

19. A drainage system as recited in claim 8 wherein said at least one main collection conduit comprises an enclosed ribbed pipe having a plurality of ribs substantially corresponding to said ribs of said ribbed surface contour of said shaped lengths.

20. A drainage system as recited in claim 19 wherein said at least one main collection conduit has a substantially polygonal cross-section.