NO341102B1 - Construction of buildings and underground facilities - Google Patents

Abstract

Construction has a seal secured at the outer side against traversing water or a anchor isolation against corrosion or a film with rough surface or a claw mat or an agent for spraying concrete with enclosed plastic foam particles. The film is held by means of sealing elements at the anchoring elements.

Description

The invention relates to structures for buildings and underground facilities, in particular the construction of underground spaces such as tunnels and tunnels or pipelines in solid rock.

Fasteners are particularly often used in tunnel construction. Here a distinction must be made between tunnels in solid rock and in loose rock. Solid rock does not collapse when the tunnel masses are blasted out. If the rock is loose, on the other hand, a structure with a large bearing capacity is required, which partially bears the weight of the rock. In loose rock, it is common to use both steel and concrete structures, sometimes combining the two materials. The concrete structures can usually be manufactured on the construction site. It is also common for concrete panels to be produced in a factory and transported to the construction site.

In solid rock, the problem of fastening disappears, but you still have to secure against stones falling from the roof. This problem is usually solved with shotcrete. Concrete is sprayed against the rock wall, hardens and forms a protective layer.

Another problem is water seeping out through the rock wall. The water freezes in winter, and thus there is a danger that masses of ice will fall down. This problem is usually solved with sealing foil. Depending on the thickness of the foil, this is also called web or membrane.

The sealing foil directs the water away. At the same time, thermal insulation prevents the water from freezing.

The sealing foil is made from foil webs. The foil webs are laid overlapping on the rock wall so that the edges can be welded together. A double welding seam is preferably used here. Two welding seams are then next to each other, and the space between them can be filled with air. When the space is closed, a sufficient sealing effect can be expected as long as the pressure drop does not exceed certain limits per unit of time.

The fixing of the foil takes place in different ways. When it is not difficult to attach, it has been common to attach the foil with a plastic attachment that is shaped like a ring. The roundel is nailed or shot directly into the rock or into a first layer of shotcrete. The fact that the rondels are shot in means that they are not driven in with a hammer or similar, but that they are driven into the rock or the first layer of concrete with the help of a blasting cartridge.

Traditional roundabouts are shown and described for example in DE-3244000C1, DE4100902A1, DE19519595A1, DE8632994.4U1, DE8701969.8U1, DE20217044U1. These are welded together with the foil. It has been considered particularly advantageous to use roundabouts with defined breaking points. The circular parts must then break there if the foil is subjected to stress. The resistance of the breaking point is significantly lower than the resistance of the foil. In this way, the disc breaks when the foil is exposed to too much pressure. This means that the sealing foil remains undamaged even if the pressure on the foil becomes too high, while the washer breaks.

However, the plastic rondels are only suitable when weak forces arise during the fixing of the foil and the subsequent application of shotcrete.

But especially in tunnels strong forces occur. In railway tunnels, the passing trains produce an extreme air pressure and then an extreme suction. The pressures act on extremely large surfaces, resulting in a total pressure which makes it necessary to have a sufficiently firm connection between the tunnel structure and the rock. The pressure depends on the speed of the train, and high-speed trains create a pressure many times higher than normal trains. The same applies to car tunnels.

For such loads, steel washers are most commonly used. These are held firmly in the rock with bolts.

Traditional roundabouts have a diameter of approx. 150 mm and a thickness of 3 to 4 mm. Such rondels have great resilience. Traditional bolts have a diameter of 12, 14, 16 or 20 mm. They are usually made of stainless steel and are profiled on the side facing the mountain to provide great resistance to being pulled out. Separate drill holes are made for the bolts. The bolts are then fixed in the drill holes with mounting cement or other suitable mounting materials. In contrast to traditional rivet constructions, such bolts can withstand strong forces. The load is directed into the rock, and therefore with such bolts it is possible to build a tunnel structure that can withstand the load of trains and vehicles driving through.

The free end of the bolt is usually fitted with a thread, preferably with a diameter corresponding to metric thread M12, M14, M16 or M20. On this side, the steel washers are held between two screws. The screws make it possible to position the washers on the bolt.

The bolts are usually so long that they protrude past the washers into the tunnel. This makes it possible to attach a wire mesh as support when spraying concrete and as stiffening of the tunnel construction through fastening in the rock.

When spraying concrete on foil, there is a risk that the foil will lose the concrete, i.e. that the concrete will not stick to the foil. Then it is expedient to set up a wire mesh or similar some distance from the foil to prevent the concrete from falling down.

The wire mesh also serves as reinforcement for the shotcrete layer.

A spacer for the wire mesh can also be mounted on the bolt. Traditional spacers are star-shaped and equipped with rods to support the wire mesh as much as possible.

With traditional construction, the bolts pierce the foil. The foil is then clamped between the steel discs, one disc on the outside of the sealing foil and the other on the inside.

In practice, it turns out that the water from the mountain flows along the bolts. This means that bolts and washers are exposed to high water loads. EP 1950375 has taken into account that the water penetrates via the screw threads in the washers and bolts and thus also through the holes that have appeared in the foil. This leads to leakage, and even a drop-by-drop leak eventually leads to significant amounts of water. These can flow into the inside of the tunnel and turn into icicles when the water freezes in winter. When the weather becomes mild again, the icicles fall and create a great risk of accidents.

In addition, the icicles can cause great damage to the tunnel construction.

To prevent water from penetrating the threads of the washer, it is common to insert a rubber ring into the hole made by the washer. However, the rubber ring has a very limited effect because it cannot sufficiently engage the screw threads of the bolt. It is true that it is common to equip the rubber ring with knobs on the side facing the threads so that it will have a better grip between the screw threads than a smooth ring, but this does not lead to a sufficient seal either.

It is also common to equip the inside of the tunnel with insulation to avoid ice formation.

The invention has set itself the goal of improving tunnel construction through a better foil.

According to the invention, this is achieved through the distinctive features of the patent claims.

As mentioned above, the foil is assembled from different foil webs.

The individual foil tracks are traditionally laid around the perimeter of the tunnel. The number of bolts and fasteners then depends on the distance between them. All external fixings should be prepared in the manner described above.

The prepared foil track is then laid, and you start, for example, at the sole on one side of the tunnel. The foil is guided up the tunnel side, and as soon as it touches the mentioned pin on the external attachment, the pin shows up on the foil and you can feel it. This can be used to cut openings in the foil at exactly these places, and this can be done either mechanically or by hand. As soon as a hole has been made in the foil, the foil can be pushed over the pin

Ideally, the foil should be attached to the relevant pin straight away. This can be done by attaching a seal to the foil and then pushing the inner attachment onto the pin.

Ideally, the foil should be attached to the relevant pin straight away. This can be done by attaching a seal to the foil and then pushing the inner attachment onto the pin.

With the invention, an optimally loadable bolt construction is created without the seal and foil being mechanically overloaded by the fastening of the fasteners. This is mainly due to the spacers between the fasteners. It is best to use rings as spacers.

A similar situation is also obtained if, instead of without further sealing, you push the fastener onto the pin and press it against the foil.

The length of the staple depends on the thickness of the shotcrete construction. It can consist entirely of concrete, but it can also have an insulating layer. Such an insulating layer is best placed behind the concrete towards the rock. The pin must then protrude through the insulating layer in order to carry the previously mentioned wire grid and the spacer with its front end.

In the case of all sealing problems, a distinction must be made between water stress from the outside, water stress from the inside and water stress that acts on the shotcrete from both the outside and the inside. To meet this, sealing foils are often used. The sealing foil can be attached to both sides of the shotcrete, but it can also be used on just one side. It can be placed on the inside of the shotcrete to prevent waste water and other liquids from seeping out.

The shotcrete can be applied in one or more layers.

It is frequently used in underground spaces in solid rock, whether it is tunnels, storage rooms, bunkers, canals or something else. Above ground, it is frequently used in open construction pits.

There are several varieties of underground use.

For example, according to DE-3244000 C a first layer of shotcrete on the rock face. This layer mainly helps to seal it. A sealing foil is placed on the first layer of shotcrete. This layer does not need to be thick. The sealing foil is usually applied in strips that must be attached to the rock or in the shotcrete. The strips are placed one after the other in such a way that the edges overlap and complement each other so that the desired seal is achieved. Where the edges overlap, they are welded together. To fasten the tracks, bolts are first placed in the rock. The sealing foil can be perforated by the bolts if the leakage points that occur are sealed.

This can be done using two flanges, at least one of which simultaneously seals with the foil. This happens, for example, by shaping the flange as a neoprene disc. The flanges must squeeze the foil between them. It is best to leave the flange towards the mountain firmly positioned while the other can be adjusted. The bolts form the connection to the rock and hold the concrete reinforcement with the shotcrete niche that enables and supports the interior

the shotcrete construction. The concrete reinforcement usually consists of steel, for example in the form of

reinforcement mats. The shotcrete niches are formed according to DE-3244000 using a wire mesh. This is placed some distance from the foil and should prevent shotcrete that hits the sealing foil from being thrown back.

Furthermore, DE2833148 presents a seal in the form of a first and a second layer of softened PVC plastisol. Into this second layer, which is in an ungelatinized state, a curly fiber mat made of polyamide fiber is partially inserted. The soft PVC plastisol is then heated and gelatinized so that the curling fiber mat is attached to and connected to the PVC plastisol layer. The fibers in the curling fiber mat can be regarded as plastic particles that are applied to the shotcrete side of the foil to be fixed there.

For other uses, the sealing foil must be installed some distance from the rock. This is done by attaching the sealing foil to the described bolts. With this use, the problem of shotcrete bouncing off is even greater than in the previous example. The wire mesh also helps just as much in this case, so that with the help of the wire mesh technique described above, a shotcrete structure can easily be erected some distance from the rock face.

As an alternative to the above-mentioned placement of the sealing foil at a certain distance, a grid or wire mesh can be used between the structure and the rock wall. In this way, the wire braid works preferably as protection against landslides from the mountain.

In the journal Forschung + Praksis, 1970, p. 184, it is described to tension the wire mesh directly against the sealing foil. Nevertheless, by spraying, you get a space between the wire mesh and the foil because the foil bulges out to a much greater extent than the wire mesh.

DE-2400866A1 and DE-36526980A1 indicate covering on the shotcrete side the sealing foil with nonwoven which can perform various tasks. According to DE-3626980, the nonwoven can fulfill different functions, both a protective function and a drainage function. According to DE-2400866, moreover, the fiber material should first be primed before the actual laying of shotcrete begins.

DE-3741699 specifies the use of sealing foil with a nub structure. Towards the rock face, the knobs must maintain a certain distance so that the water that penetrates out of the rock can drain away.

DE-3823898 indicates using the bumpy structure on a sealing foil for other purposes, namely to hold back the shotcrete.

According to this invention, the sealing foil must have a special design.

The minimum stiffness is achieved with unfoamed olefin foil, especially with polyolefin foil, e.g. polyethylene foil (PE foil). Copolymers can also be used, e.g. ethylene copolymer.

All PE is suitable as a sealing foil. This includes, among other things, LD polyethylene, HD polyethylene and polypropylene (PP).

The stiffness is created by a minimum thickness of 1.5 mm, but preferably at least 1.8 mm. For other foil materials, the thickness is increased until the desired stiffness is achieved.

The roughness of the surface occurs when particles of the same material as the foil are applied even on the side of the foil surface that faces the shotcrete. The particles can have different shapes, but an elongated shape is preferable. This includes, for example, thread or string form. The material is easily melted on the surface before the particles are applied, so that the particles adhere to the foil surface when touched. The material must not be melted so that it becomes liquid in the core. For solidification to take place, the surface temperature must be higher than the melting point of the substance in question. The temperature should be somewhat above this so that a rapid heating occurs. An open flame or other methods are used for this. Plastic particles are produced, for example, by grinding up granules of 2 to 8 mm so that they have a cross section of 2.1 Vi or most preferably 0.2 to 1 mm. The amount to be applied is determined by the surface weight of the material being applied. Measurements according to basis weight is also known from textiles. According to the invention, at least 20, 50 or preferably 100 grams or more per square meter must be applied. In practice, application amounts of up to 500 grams and more per square meter will be used. Details and variations in the application of particles are described in the following publications: AT 194605, CH332229, DE4207210A1, DE19718035C, EP901408A

or in WO 97/37772 or PCT/US97/05029, US 2987104, US 5612081, US 5075135, US 3622422, US 2936814.

You can also preheat the foil surface further for the material application to get a better connection between the particles and the foil surface. This pre-heating is not necessary if you use the heat from the production of the foil.

Conventional production of the foil takes place by extruding the material. With the help of an extruder, the molten dough-like plastic is sent through a nozzle and into the gap of a pair of rollers. When the plastic enters between the rollers, it may already have a foil shape. This is achieved using a slit nozzle. The slot in the nozzle then has a length and width that correspond to the shape.

The melt-like plastic can also be sent into the gap in granule form or strip form so that plastic plasticine is formed which is continuously drawn through the roller gap so that foil is formed between the rollers.

Between the rollers in the roller pair, the foil gets the exact desired thickness, possibly after repeating the process one or more times. For the first roll pass, the foil width is not decisive. The rolling produces a more or less snake-shaped foil edge, and therefore this is cut along the side when the rolling is over. The edge strips that are left over are fed back into the extruder and are thus converted into new melt dough-like starting material for the rolling process. During the rolling process, the foil gets a significant temperature. This temperature can be used when applying particles to roughen the surface.

Post-heating can also be carried out so that the particles adhere better to the foil surface. Optionally, you can also press the particles onto the foil surface with roller pressure so that the particles adhere even better to the foil surface.

Nevertheless, EP901408A assumes that the welding factor for the connection between particles and foil surface is significantly lower than 1.

This is considered advantageous in view of the fact that, under a given load, the particles can loosen again, without the sealing foil being destroyed.

The heat can also be applied to the particles just by using hot gases. It is possible to dose the particles into the hot gas flow. The residence time in the hot gas determines the degree of solidification. This time depends on the distance the particle travels before it hits the foil surface and on the speed of the gas.

The heat can also be supplied as pure radiant heat by the particles falling through a heating channel and melting easily on the surface as they fall.

Conventional production of the foil takes place by extruding the material. With the help of an extruder, the molten dough-like plastic is sent through a nozzle and into the gap of a pair of rollers. When the plastic enters between the rollers, it may already have a foil shape. This is achieved using a slit nozzle. The slot in the nozzle then has a length and width that correspond to the shape.

The melt-like plastic can also be sent into the gap in granule form or strip form so that plastic plasticine is formed which is continuously drawn through the roller gap so that foil is formed between the rollers.

Between the rollers in the roller pair, the foil gets the exact desired thickness, possibly after repeating the process one or more times. For the first roll pass, the foil width is not decisive. The rolling produces a more or less snake-shaped foil edge, and therefore this is cut along the side when the rolling is over. The edge strips that are left over are fed back into the extruder and are thus converted into new melt dough-like starting material for the rolling process. During the rolling process, the foil gets a significant temperature.

You can also simultaneously create a profile as described in DEI 9721799.

The less elastic the sealing foil is, the easier it is to lay the shotcrete. The elasticity is, on the one hand, dependent on the foil thickness, and on the other hand, on the installation of the foil. The more evenly distributed attachment points the sealing foil has, the stiffer it becomes. Preferably, the attachment points should be placed so that four adjacent attachment points form the corners of a square. The side length in the square is then the same as the distance between two adjacent attachment points. The smaller the distance between the adjacent attachment points and thus the side length of the square, the more attachment points are needed. If the foil thickness is 2 mm, there should be a distance of 1.2 m between adjacent attachment points. The distance should not be more than 15% or preferably not more than 7.5% higher than this. Adjacent means the closest attachment points.

The permitted distance can be changed by changing the position of the fasteners. Then you reduce the distance between them until you get a construction that is at least as rigid as when placed at the corner points of a square.

If the foil is thicker, the permitted distance between adjacent attachment points increases. The distance can only be increased so much and/or the position of the attachment points changed so much that, despite the thicker foil, the structural rigidity described above is retained.

If the foil is thinner than 2 mm, the permitted distance between two adjacent attachment points is reduced. The distance is reduced so much and/or the position of the attachment points is distributed so that, despite the thinner foil, the structural rigidity described above is retained.

The build-up of the shotcrete construction becomes easier with priming of the sealing foil. Priming according to the invention contributes, in addition to the surface design mentioned above, to the shotcrete being attached to the sealing foil and the geotextile sheet. The priming can be done with the same cement, adhesive or binder that is used for the shotcrete, just without the aggregates used in it. Cement/adhesive/binder can be used in powder form and mixed with water before application to the foil surface and sprayed on with a nozzle in a misty form, or sprayed on in misty form together with cement/adhesive/binder in powdery form.. It can also be used a special primer with a synthetic film with mineral aggregate. At the same time, the mineral aggregates in the glue provide a better adhesive effect for the shotcrete.

The fog-like spraying of the primer leads to a thin moisture layer on the foil surface. The thickness of the moisture layer is set so that the primer does not start to flow due to its own weight. In practice, the amount of application is reduced until you can no longer observe that it is running.

If the speed of the primer out of the nozzle is kept constant, the amount of application can be regulated with the speed at which the nozzle is moved. If the amount of application is to be reduced, this is achieved by moving the nozzle faster over the application surface, in this case the sealing foil. If the sealing foil is sprayed several times in the same place, the application can be reduced by reducing the number of applications.

If spraying is repeated at the same place on the sealing foil, the amount of application can be reduced by reducing the number of repetitions.

If desired, water-absorbing materials can be mixed into the primer.

After priming, the shotcrete can be laid in one or more layers on the sealing foil. It is then advantageous to lay the shotcrete on, one layer at a time, and to start at the bottom. This is done using a back and forth movement with a tool for laying shotcrete. Man kan bruke sprøytebetong, betong, tilsetningsstoffer, tilslag, forsterkningsinnlegg og slikt verktøy som er beskrevet i følgende trykksaker: DE69910173T2, DE69801995T2, DE69721121T2, DE69718705T2, DE69701890T2, DE69700205T2, DE69418316T2, DE69407418T2, DE69403183T2, DE69122267T2, DE69118723T2, DE69010067T2, DE69006589T2, DE60010252T2, DE60001390T2, DE29825081U1, DE29824292U1, DE29824278U1, DE29818934U1, DE29724212U1, DE29718950U1, DE29710362U1, DE29812769U1, DE19854476C2, DE19854476A1, DE19851913A1, DE19838710C2, DE19819660A1, DE19819148C1, DE19754446A1, DE19746958C1, DE19733029C2, DE19652811A1,DE19650330A1.

The drawing shows various examples of the design of the invention.

Fig. 1 shows a rock wall (1) in solid rock. Bolts are inserted into the rock at regular intervals. For this, the necessary holes were drilled, and the bolts were fixed with mounting cement in these. The bolts are produced at the center axes (2).

The mountain wall (1) will be used to make a tunnel. To drain water that seeps out and to protect against falling stones, a shotcrete structure must be made in the rock face.

The shotcrete construction roughly consists of a layer of foil (4) and a layer of shotcrete (3). The layer of foil (4) is composed of simple webs that are laid so that they overlap each other and the edges are welded together. It is made with two welding seams that lie next to each other with some distance between them. The cavity between the welds is filled with compressed air to check that the welds are tight.

Details of the shotcrete construction are shown in Figure 2. A bolt (5) is shown schematically. At the end that protrudes from the rock, the bolt (5) is connected to a fastener (14). The layer of foil (4) is adjacent to the attachment (14).

On the other side of the layer of foil from where the attachment (14) is located, is another attachment (15). The fasteners (14) and 15) clamp the layer of foil between them.

In addition, the fasteners carry a spacer (13) for a wire mesh (12). The wire mesh (12) has two tasks. It contributes to the laying of the shotcrete layer (3) by preventing concrete that bounces off the foil from falling down. In addition, the wire mesh (12) forms a reinforcement for the shotcrete layer. The shotcrete construction weighs so much in relation to its shape that without the bolts it would collapse before it had solidified. The bolts guide the weight of the shotcrete structure into the rock. After the shotcrete structure has solidified, the bolts form a firm connection between the structure and the rock.

Fig. 5 shows a possible hexagon structure (43) for the wire netting shown in fig. 2.

Fig. 4 shows a spacer (40) for positioning the wire mesh. The spacer (40) is pressed against the screw nut (25) with another screw nut. The spacer (40) has various arms where the wire mesh (43) can be attached.

Figure 6 shows a suitable foil for shotcrete construction. The foil (110) is 2 mm thick and strewn with strings of material. The material strands (111) have a thread-like structure with a thickness or cross-sectional dimension of 0.1 to 0.3 mm and are from 5 to 50 mm long. The material strands (112) have a thickness of 1 to 2 mm and are from 10 to 30 mm long. In the example, the different strands of material are applied in separate rounds in order to be able to heat up strands with a large cross-section in a different way than those with a small cross-section. In other examples, the strands of material are applied in one common pass. The material strands lie hollow to bolt above each other so that there are partial hollow formations in the material strands. In this situation, the material strands (112) form elevations of up to 3 mm. Parts of the foil surface remain uncovered. The material spread has a surface weight of 250 grams per square metre. In other examples, both higher and lower basis weight may occur. Lower surface weight occurs especially when the foil surface is profiled. In such cases, it is possible with an area weight as low as 20 grams per square meter.

A higher surface weight is expedient when, depending on the composition of the shotcrete, there are difficulties with laying that must be overcome.

After they themselves have been heated on the surface, the different strands of material in the example are strewn on the foil (10) which has previously been surface heated. The strands of material have been heated on the surface until it has melted and liquefied. The heating takes place with radiation by the material strands being taken out of a storage container with the help of a cell wheel lock and dropped through a heating channel onto the foil which is slowly passed by. In the example, the heating channel has a large number of electrically driven heating wires and a temperature control. In this way, the temperature in the heating channel can be increased until the material strands that fall through have the correct surface temperature.

After the installation of the foil in the tunnel, a quick-setting slime is first sprayed onto the foil. When the slime has dried, it forms a good primer for a subsequent laying of shotcrete. The shotcrete is laid in layers, starting at the tunnel sole.

In the example, the tunnel runs horizontally so that the shotcrete is laid in horizontal layers from the bottom up on the foil. The layers have a width that corresponds to the desired thickness of each layer of shotcrete. In other designs, the layers are narrower. Then a first layer of shotcrete is first placed on the foil, which covers the entire foil side. A new layer of shotcrete is then applied, completely covering the previous layer. This is repeated until the layer of shotcrete has reached the desired thickness.

After the shotcrete layer has been laid, the bolts still stick out of the concrete layer.

Claims (12)

1. Tunnel constructions in solid rock (1), with foil as a seal (4) against water using bolts (5) which are inserted into the stable rock (1), the foil is held on the bolts by means of fasteners (14, 15), at the same time that the foil is clamped between two fasteners (14, 15), one of which is on the outside of the foil and the other is on the inside and the external attachment (14) has a connection with the bolt (5) and a layer of shotcrete (3) is placed on the foil, which is characterized by the use of a foil (11) which has a roughened surface on the side where the shotcrete is laid, and which is formed by the application of plastic particles (111,112), at the same time that the plastic particles (111, 112) have a wire shape with a cross-section of 0.1 to 2 mm and a length of 5 to 50 mm and they (111, 112) are first melted and then sprinkled or applied on the shotcrete side of the foil to attach there. 2. Construction in accordance with claim 1 characterized by a) that many bolts (5) are placed in the rock wall as fasteners for the foil (110). With a foil thickness of 2 mm, these must be attached at a distance of 1.2 meters or, at most, exceeding this by 15%. If the foil (110) has a lower thickness, the distance between the attachment points must be reduced so much that the foil (110) becomes as stiff as a 2 mm thick foil (110) with a distance of 1.2 meters plus or minus 15%. If the foil is thicker, the distance between the attachment points must be increased as much as possible so that the foil (110) has the same stiffness as a 2 mm thick foil (110) with a distance of 1.2 meters plus or minus 15%. 3. Construction according to claim 1 or 2 characterized by the fact that the plastic particles (111, 112) fall freely through a heating channel or are heated with a flame when applied. 4. Construction according to claim 3 characterized by the fact that the plastic particles (111, 112) are introduced into a hot gas stream during application and that they (111, 112) are accelerated in this towards the foil side. 5. Construction according to claim 3 or 4, characterized in that a stationary mounted mechanism is used for heating the plastic particles (111, 112) and that the foil (110) is moved past this. 6. Construction according to claim 5 characterized by the fact that the side of the foil which should face the shotcrete is heated before and/or after the particles are applied. 7. Construction according to one of the requirements, requirements 1 to 6, characterized by material strands of different diameters being heated and applied separately. 8. Construction according to claim 7 characterized by the use of material strands with a diameter of 0.1 to 0.3 mm and with a diameter of 1 to 2 mm. 9. Construction according to one of claims 1 to 8, characterized by the fact that the material strands are laid bolt to bolt above each other. 10. Construction according to one of the requirements 1 to 9, characterized by the fact that material is sprinkled with a surface weight of at least 20 grams per square meter, but rather 50 grams per square meter and preferably 100 grams per square meter. 11. Construction according to one of claims 1 to 10, characterized by the fact that not only is the shotcrete laid in horizontal layers above each other, but that also with regard to the foil surface, several layers are applied on top of each other. 12. Construction according to one of the claims 1 to 11 characterized by a primer on the side of the foil (110) which is to face the shotcrete at the same time that the primer is composed of a plastic film and mineral aggregates in the glue.