Drainage System for use in tunnels

Abstract: During tunnel construction, the water emerging at various locations in the rock wall 2 must be removed through a drainage system 1 so that it does not endanger the shotcrete or other securing coating applied to it. This is achieved with a manufacturing process in which HDPE films of high impact resistance and tear resistance are heated in an appropriate form for a deep drawing process and drawn over a positive form by application of a vacuum, and so moulded that the same surface contouring is produced over the entire length in the arch area with smooth lateral parts. The shaped length 5 consists of an arch-shaped middle section 18 having sine-wave shaped ribs 9, 10, 11 and lateral parts 6, 7 running at an angle to this having no contouring, with single ribs 21 at predetermined intervals, running right across to the edges 19, 20 of the shaped length 5, which permit bending to either side. Shaped lengths 5 of this kind and moulded parts 12, 13, 14 are also not impaired or damaged by application of shotcrete, so that thereafter, the water which would otherwise endanger the shotcrete can be safely and lastingly conducted away.

Description: The invention concerns a process for the manufacture of a drainage system consisting of multiple parts for connecting 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 construction in order to collect the water forcing through the rock surface and conduct it in a controlled manner under the finish covering, especially shotcrete, to the main collection conduits, the shaped lengths with the lateral parts and the moulded parts being made from plastic. The invention also concerns a drainage system for surface water emerging under pressure out of the rock walls under the finish covering, especially concrete, particularly in tunnel construction, consisting of arched shaped lengths with angled lateral parts on both sides and a surface contour having ribs running perpendicular to the longitudinal axis and moulded 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 consisting of flexible sealing material, with which the joints and gaps remaining in the concrete cladding are covered over are covered over, in order to collect the water emerging there and to conduct it away in a controlled manner. The shaped lengths consist of an arched middle part and lateral parts capable of being bent down moulded onto it. 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 consist 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 flow through them. Furthermore, attachment to the rock surface through adhesion is not possible in practice. CH-PS 479 777 dated 1968 describes a so-called open channel having laterally moulded 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 consists 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. US-PS 3,699,684 reveals a drainage pipe made of flexible material, whereby these pipes are placed into previously prepared incisions or channels, in order to conduct 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. US-PS-4, 360, 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 surface profile is provided, consisting of 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 consists 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 consisting of a suitably flexible shaped length and associated moulded parts, whereby both the shaped lengths and the moulded 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 moulded 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 to be applied under appropriate pressure. Even the ribbed surface contouring is not sufficient to prevent destruction of the moulded parts or shaped lengths. Also disadvantageous is the fact 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 the 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 is therefore based on the aim of creating 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 conduction of water. The aim is fulfilled by the invention in that films or thin-walled boards made from HDPE of high impact resistance and tear resistance with a width chosen to be slightly greater than the subsequent shaped lengths are heated for a deep drawing process and are drawn over a positive form by application of a vacuum and are so moulded that, over the entire length in the arched region, the same surface contouring with smooth lateral parts is produced. By means of this kind of manufacturing process, 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 more or less fine quartz particles contained in the shotcrete are guarded against by the very dense PE material with its high level of impact resistance, without the possibility of any significant damage arising, so that, in any event, the hollow space remains intact through which, after covering with the shotcrete, the surface water or the water emerging from the rock surface can be conducted without being able to cause any damage to the tunnel lining. Of further advantage is the fact that, due to the surface contouring being the same over the entire length, a secure overlapping and therefore linking with the moulded parts is possible, these also possessing the same surface contour in the join 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, these being 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 moulded parts shaped to fit the anchor heads or attaching points of the shaped lengths are deep drawn from the films or thin-walled boards, such that they are given the same or a slightly larger contour than the shaped lengths in the later joining regions. The moulded parts, which secure only relatively short sections are also made from the same material and in the same manner, so that even with a disadvantageously applied covering of shotcrete, continuous drainage is assured. The profiling in the joining region makes possible a safe coupling to the relevant part of the shaped length, and without any additional sealing material needing to be used. Rather, by means of the overlapping of the shaped parts provided with contouring and of the shaped lengths, a kind of labyrinth seal 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 moulded parts keeping to later precise specifications is possible if films or boards of a thickness between 0.8 and 1.5 mm, and preferably 1.2 mm, are used for the shaped lengths and the moulded parts. With 1 mm and thicker films and boards, also, deep drawing is possible, and precise profiling when deep drawing, so that the connection of the individual parts of the drainage system is sure, as is a sufficient wall thickness also in all areas of the moulded parts and shaped lengths. It has proven that not every PE material is suitable for the manufacture of appropriately advantageous drainage systems. The invention provides for the shaped lengths and moulded parts being 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 lives even under heavy loading. With the help of the process according to the invention, a drainage system is made that consists of multiple parts, whereby this drainage system itself is to be protected, whereby apart from the shaped lengths with angled lateral parts on both sides, moulded parts are also provided that have ribs in the connecting region which are the same as or correspond to those of the shaped lengths. The shaped lengths themselves consist of an arched middle section with sine wave-shaped ribs and the lateral parts running at an angle to it without any contouring, they being formed in 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 also of shotcrete, and can be securely attached in the edge region to the rock surface with nails, anchors or similar, while simultaneously providing a seal because the lateral parts have a smooth surface, and can be installed bent according to the prevailing conditions, since single ribs running through to the edge are provided at an equal distance from each other, which permit bending to either side. It is conceivable that the moulded 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 development of the invention is one where the continuous single ribs are formed to be correspondingly as broad as, or broader than, the other ribs. As previously mentioned, this means that overlapping in order to connect neighbouring drain parts is possible without difficulty, because in the important area of connection with the rock wall the 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, as one single rib overlaps two positive ribs without presenting any problem for the joint. It has already been indicated several times that the moulded parts are so formed in the connection region that an overlap or connection with the neighbouring shaped length is achieved. This is made possible, in particular, through the fact that the moulded parts are provided with coupling ribs corresponding with 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 neighbouring shaped length. However, they should not be too large, since then the necessary labyrinth seal could be impaired. Of particular importance is the catching of the water that emerges in the region of anchor heads, this being obvious since the anchors or the holes drilled to accept them may possibly transect several water-conducting slip planes and fissures. Therefore, the invention allows for the moulded anchor parts associated with the anchor heads having a cap that accepts the anchor end, anchor nut and possibly the domed plate. In this way, a moulded anchor part of this kind can be placed over the entire anchor head in order to seal this area and to ensure that the water emerging here is conducted through the drainage system. This is particularly so when the moulded anchor part of the domed plate has a rectangular shape and a receptive sealing bead is formed around it. The sealing bead simply ensures that the emerging water does not seek other routes, but is collected by the moulded anchor part and conducted away through the drainage system. In this respect, it is suitable if the sealing bead is produced through shaping or if, through tapering of the bent-over edges, an approximate linear contact with the rock surface is produced, since in this way, a sealing bead in the proper sense, that is, an additional moulded part, is not required at all. Rather, the entire moulded part - the moulded anchor part in this case - simultaneously provides the sealing region, thus resulting in a simpler manufacturing processes. It cannot be avoided that the rock surface might comprise protruding parts in the area of the relatively small moulded anchor parts. In order to achieve adaptation to the rock surface here, the invention provides for the moulded anchor parts having moulded ribs the same or similar and running parallel to the ribs of the shaped lengths. In this way, the entire moulded anchor part can be easily bent and so adapted to the existing shape of the rock surface. The prior art involved use of a main collection conduit, consisting of 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 necessarily straight and is generally not, this being assisted 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 fits less well to the contours of the rock surface than the previously described ribbed pipe. However, this rectangular-section pipe can have advantages for particular application purposes, for which reason it is mentioned in particular here. The invention distinguishes itself in particular through the fact that a drainage system is created that can be used to particular advantage where shotcrete has to be applied for stabilisation of the rock surface. Even under this problematic coating, maintenance of the effectiveness of the drainage system employed, it being manufactured from the particular PE material, is assured, so that when the shotcrete is applied, no particular precautions need to be taken. This applies both for the shaped lengths used and for the moulded parts, so that the 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 there at all. The moulded parts can, through appropriate forming, 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. Of advantage here is both the connection of the shaped lengths with the individual moulded parts, and particularly the moulded anchor parts, as well as with the main collection conduit, so that it can be guaranteed with the necessary degree of certainty that pressurised water will not endanger the tunnel wall, even after a long service life. Further details and advantages of the invention arise from the following description of the attached drawings, in which a preferred embodiment with the necessary details and the individual components is represented. They show the following: Fig. 1 a simplified representation of a drainage system attached to a rock wall Fig. 2 a top plan view of a shaped length Fig. 3 a part section in the area of the middle section of a shaped length Fig. 4 a plan view of a moulded anchor part Fig. 5 a section of a moulded anchor part Fig. 6 a section of a drainage system installed on a rock surface, or a shaped length in this drainage system Fig. 1 shows a drainage system 1 already mounted on a rock wall 2, so that the water emerging from individual sections of the rock wall 2 can be reliably conducted to the main collection conduit 4 laid on the tunnel floor 3. The drainage system 1 consists of shaped lengths 5 with surface contouring 8 and smooth lateral parts 6, 7. It can be seen that these lateral parts 6, 7 are attached with nails 16, 17 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 consists of wave-shaped ribs 9 10, 11, whereby these ribs 9, 10, 11 comprise regularly shaped waves, which simplify installation, and simultaneously improve the stability and simplify application of the shotcrete, because they represent a kind of adhesion zone for it. This multiple effect is particularly advantageous so that in the area of the relatively narrow lateral parts 6, 7 no adhesion is provided, or at best through the nails 16, 17. The shaped lengths 5, 5', 5" are connected by means of the moulded parts 12, 13, 14 to each other or to appropriate parts. Thus the moulded part 12 serves to connect to the main collection conduit 4 laid on the tunnel floor 3, while the Y-piece that is the moulded 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. These anchor heads 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 moulded anchor part 14. Figure 2 shows a plan view of a part of a shaped length 5, such that it is clear that only the middle section 18 is provided with ribs 9, 10, 11. These ribs 9, 10, 11 are distributed evenly over the whole 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 in Fig. 1. While the middle section 18 has ribs 9, 10, 11 and single ribs 21, in the area of the lateral parts, there are none, or only continuous single ribs 21. 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. Fig. 3 shows how the single ribs 21 can be formed differently from Fig. 2. Here an arch-shaped single rib 21 is represented 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 moulded parts 12, 13, 14, overlapping 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 in that a sufficiently broad connecting region 25 is provided. Figs. 4 and 5 show a moulded anchor part 14 in plan view and in section, wherein it is clear that coupling ribs 26 are provided in the connecting region 25, facilitating connection with adjoining shaped lengths 5 because they are made slightly broader. In this design of the moulded anchor part 14, it is important that it covers the entire anchor as far as possible, as is made clear in Fig. 5. The anchor bolt 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 using the anchor nut 29. Fig. 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 here, but rather is caught in the moulded anchor part 14 and is then conducted through the connecting region 25. Fig. 4 shows a special embodiment to the extent that here, too, moulded ribs 33, 33' have been formed, so that this moulded anchor part can be bent according to the shape or the rock wall 2, in order that a better seal can be achieved. Fig. 6 shows a drain 1 installed on a rock wall 2, wherein it is clear that these drains cover, by way of example, water-conducting fissures 36 in order to collect the water emerging from them and to conduct it safely under the shotcrete, which is not shown here. Identifiable here are the fixing nails 37 that are inserted through lateral parts 6, 7 into the ground and thus enable effective attachment. In Fig. 1 these fixing nails are identified as 16 and 17, whereby these attachment means can also be small anchors or similar items. Fig. 1 makes clear that the lateral parts 6, 7 can possess a raised edge 38, in order to introduce sealing material 39 here, 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 to the lateral parts 6, 7, but offset close to the middle section 18 or to the edges 38, 40. All the features named and those that are only to be found in the drawings are to be regarded singly and in combination as essential components of the invention.

Claims: Process for the manufacture of a drainage system consisting of multiple parts for connecting 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 construction in order to collect the water forcing through the rock surface and conduct it in a controlled manner under the finish covering, especially shotcrete, to the main collection conduits, the shaped lengths with the lateral parts and the moulded parts being made from plastic, characterised in that films or thin-walled boards made from HDPE of high impact resistance and tear resistance with a width chosen to be slightly greater than the subsequent shaped lengths are heated for a deep drawing process and are drawn over a positive form by application of a vacuum and are so moulded that over the entire length, in the arched region, the same surface contouring with smooth lateral parts is produced. Process according to Claim 1, characterised in that moulded parts designed to fit the anchor heads or attachment points of the shaped lengths are deep drawn from the films or thin-walled boards, such that they are given the same or a slightly larger contouring in the subsequent region of connection with the shaped lengths. Process according to one of the above claims, characterised in that as the starting material for the shaped lengths and the moulded parts, films or boards of thickness between 0.8 and 1.5 mm and preferably 1.2 mm are used. Process according to one of the above claims, characterised in that the shaped lengths and the moulded parts are made from an HDPE with a formulation corresponding to that of the plastic used to make refuse bins. Drainage system for surface water, especially the water emerging in tunnel construction from the rock walls (2) under pressure beneath the covering coating, above all concrete, consisting of shaped lengths (5) having an arched profile with angled lateral parts on both sides (6, 7) and a surface contouring (8) in the form of ribs (9, 10, 11) running at right angles to the longitudinal axis, and moulded parts (12, 13, 14) that ensure either a connection of confluent shaped lengths (5) or the main collection conduit (4) through overlapping or the attachment of collection hoods, for instance to anchor heads (15), characterised in that the shaped length (5) consists of an arched central section (18) having sine-wave shaped ribs (9, 10, 11) and the lateral parts (6, 7) running at an angle to it and having no contouring and is formed out of a single piece of HDPE of a special formulation with high impact resistance and having single ribs (21) each running right across to the edges (19, 20) of the shaped length (5) at predetermined intervals. Drainage system according to Claim 5, characterised in that the single through ribs (21) are formed to be suitably as wide or wider than the other ribs (9, 10, 11). Drainage system according to one of the above claims, characterised in that the single ribs (21) have the width of two positive ribs (22) and one negative rib (23). Drainage system according to one of the above claims, characterised in that the moulded parts (12, 13, 14) are provided with coupling ribs (26) in the connecting region (25) that correspond with the ribs (9, 10, 11) of the shaped lengths (5). Drainage system according to one of the above claims, characterised in that the moulded anchor parts (14) designated for the anchor heads (15) have a cap (31) that accepts the anchor end (28), the anchor nut (29) and possibly the domed plate (30). Drainage system according to one of the above claims, characterised in that the moulded anchor part (14) is formed square to suit the domed plate (30) and a sealing bead (32) is formed as a female element all the way round it. Drainage system according to one of the above claims, characterised in that the moulded anchor part (14) possesses moulded ribs (33) the same as or similar to the ribs (9, 10, 11) of the shaped lengths (5) and running parallel to them. Drainage system according to one of the above claims, characterised in that the sealing bead (32) is provided through shaping or tapering of the downward angled edge (34) to produce an approximate line of contact with the rock wall (2). Drainage system according to one of the above claims, characterised in that the main collection conduit (4) is formed as an enclosed ribbed pipe, such that its ribs are formed to correspond to the ribs (9, 10, 11) of the shaped lengths (5). Drainage system according to one of the above claims, characterised in that the main collection conduit (4) is formed as a polygonal-section, preferably rectangular-section, pipe.

Inventors: KASSELMANN JOCHEN, KASSELMANN, JOCHEN
Applicants: MINOVA INTERNAT LTD, MINOVA INTERNATIONAL LIMITED
Application year: 1999
Main classification: E21F16
IPC codes: E21F16, E21D11