The present invention relates to a temporary tunnel for shielding a road from falling hillside rocks. In many mountainous countries, like Norway and

Switzerland, the roads are often subjected to falling rocks and landslide. Most of such incidents are minor, but still of an extent that can cause personal injury and loss of life if they hit a vehicle.

Technical Field

The present solutions to avoid injuries is to secure the rock itself from falling out. This is done by clearing loose rocks and secure larger areas by a steel net or a steel mesh combined with wire mesh fences. This is work that needs to be carried out at height in difficult and little accessible terrain. It is very costly, the road need to be closed for traffic and not least, such work is very hazardous and risky for persons. In addition, long time is often passing before such work is decided and commenced, and also takes a long time to carry out. Even after a professional work is finished, there are still no guarantees against falling rocks or ice blocks.

The present invention seeks to avoid all this by using a temporary tunnel that can promptly and easily be deployed where the risk for falling rocks and landslide is prevalent. This means that a shield above the traffic is created instead of attempting to secure the entire hillside. A temporary tunnel section will be possible to manufacture within a few weeks, alternatively be stored at districts having high risk for falling rocks and landslide in order to be promptly deployed when needed.

Moreover, within existing tunnels, there is often a need for protection against loose rocks, and sometimes also a need for extending existing tunnel mouths or outlets. The present solutions for securing tunnels are time demanding and the traffic is severely affected. By the new temporary tunnel, the mouth of the tunnel and the tunnel itself can be rapidly secured.

Still another area of use of such a temporary tunnel, is to secure areas where construction activity takes place over or adjacent to heavy traffic road, bridge construction etc. Then it will be possible to let the traffic pass safely and unobstructed while construction takes place.

To make tunnels through rocks is a well known art that traditionally has included both drilling and blasting in the rock in order to make a tunnel. However, as far as we are aware of, a temporary tunnel for shielding a road from falling hill side rocks and landslides, has previously not been proposed.

Summary of invention According to the present invention, a temporary tunnel of the introductory said nature is provided, which is distinguished in that the tunnel comprises an elongated, open ended sheet metal dome combined with a metal wire mesh covering the dome, which wire mesh being designed and dimensioned to catch and hamper larger rocks to penetrate the elongated sheet metal dome said metal dome (1 ) comprising a plurality of hinged connections (B) pivotally connecting a part of the metal dome (1 ) so that the part of the elongated sheet metal dome (6a, 6b , 6c) is adapted to be folded.

In one embodiment the sheet metal comprises corrugated plates.

Preferably, the tunnel is being prefabricated in a factory and subsequently transported to the site for being deployed and erected there.

Normally the elongated open ended sheet metal dome is to be unfolded along a longitudinal top line of the dome. In one embodiment, the dome includes nested and folded elongated dome elements, which dome elements being exposed when the dome construction is being unfolded. Preferably, the dome elements comprises three elongated dome elements folded into a triangular cross section internally of and in top of the elongated dome construction.

Preferably, the three elongated dome elements hare hinged together in the longitudinal direction thereof.

Further, the elongated dome construction is erected by means of powered extendable means, such as a hydraulic cylinder. The powered extendable means are acting vertically and horizontally to elevate and unfold the three elongated dome elements and to widen out the road contacting parts of the dome construction in order to widely open the tunnel cross section. The hinged connections (B) can further have locking means to lock the dome elements (6a, 6b, 6c) in position.

The invention further relates to a method for installing a temporary tunnel according to any one of the claims 1 -1 1 , the method comprising the following steps

a) Transporting the temporary tunnel in a folded position to the road to be shielded, by retracting a part (6a, 6b, 6c) of the metal sheet dome into the inside of the tunnel,

b) Unfolding the temporary tunnel at the road to be shielded to an unfolded position where the entire metal sheet dome (1 ) is exposed through the entire periphery (3, 6a, 6b, 6c, 3) of the metal sheet dome (1 ).

In the folded position the remaining part that is not retracted inside the metal dome, constituting the exposed surface to the surroundings In the unfolded position it is the entire periphery or the metal dome that constituting the exposed surface to the surroundings.

Brief description of drawings Other and further objects, features and advantages will appear from the following description of preferred embodiments of the invention, which is given for the purpose of the description, and given in context with the appended drawings where: Fig. 1 shows in perspective schematic view a temporary tunnel according to the present invention being transported on a lorry,

Fig. 2 shows a schematic elevation view of the lorry and tunnel shown in fig. 1 ,

Fig. 3 shows a schematic rear view of the open-ended tunnel and lorry,

Fig. 4 shows in perspective schematic view the tunnel unloaded from the lorry and deployed on the ground,

Fig. 5 shows a schematic rear view of the open-ended tunnel shown in fig. 4, Fig. 6 shows in perspective schematic view the tunnel according to fig. 5 where each pair of ground contacting supports are fully brought apart and the tunnel is prepared for next steps in order to be expanded to full scale tunnel profile, Fig. 7 shows a schematic rear view of the fig. 6 situation,

Fig. 8 shows in perspective view the first step of tunnel expansion into full profile tunnel,

Fig. 9 shows a schematic rear view of the fig. 8 situation,

Fig. 10 shows in perspective view the second step of tunnel expansion into full profile tunnel,

Fig. 1 1 shows a schematic rear view of the fig. 10 situation,

Fig. 12 shows a schematic rear view the third and final step of tunnel expansion into full profile tunnel, where all tools are removed,

Fig. 13 shows an enlarged detail of the metal wire mesh externally covering the sheet metal tunnel roof,

Fig. 14 shows in perspective view the third and final step of the tunnel expansion into full profile tunnel, and ready to be fixed to the ground and subsequent traffic use. Fig. 15 shows the deployed temporary tunnel being used by two meeting lorries, Fig. 16 shows a top and elevation view of same as in fig. 15, and

Fig. 17 shows an end view of two meeting lorries in a tunnel according to the present invention.

Detailed description of the invention

The folded position is the position where a part of the tunnel is retracted at the inside of the tunnel. Only the remaining part of the tunnel is thus exposed to the surroundings. The tunnel has in this position reduced cross section viewed from an open end of the tunnel. Figure 1 -7 shows the tunnel in this position.

The unfolded position is the position of the temporary tunnel where the entire tunnel is exposed to the surroundings. The cross section of the open end of the tunnel is thus larger than in the folded position. Figure 9-17 shows this position.

By the wording exposed to the surroundings is meant the outer surface of the tunnel adapted to be exposed to falling rocks or elements etc.

Reference is first made to fig. 1 and 2 showing a temporary tunnel section 1 according to the present invention being transported on a lorry 2. The tunnel section 1 takes form of an elongated dome. The most easy and rapid solution to set up a temporary tunnel, is to transport tunnel sections 1 in one piece and have them installed at location and have them supported directly on the existing roadbed and have them immobilized by securely fixation to the ground. The tunnel section profile needs to be less than the smallest existing tunnel (if any) profile on the road in question. Hence, it is conceivable to make a temporary tunnel according to the present invention in its simplest embodiment (as defined in claim 1 ) as a sturdy tunnel construction in one piece.

If the above is not acceptable or possible, then the temporary tunnel

construction needs to be foldable such that the temporary tunnel construction can be transported through the same tunnel profile. Hence, a little more complicated embodiment will be of a foldable construction in order to reduce the cross-section area of the tunnel profile to enable passage through existing road tunnels. The thought is that the temporary tunnel sections are transported during nighttime to final destination and be ready to be installed the following morning and instantly be prepared for traffic through the temporary tunnel. This folded position also makes the tunnel easier to transport on the lorry 2. As shown in fig. 1 and 2, the tunnel section 1 construction is made up by steel profiles 3 and corrugated sheet metal plates 4 and covered by heavy gauge steel wire mesh 5 or nets fixed externally of the sheet metal plates 4. The net 5 is to secure that larger stones or rocks do not pass through the steel plates, and the steel construction ensures sufficient capacity by taking up deformation energy higher than those values used for hillside securement today. The criteria of dimensions is to ensure that vehicles inside the tunnel are not hit by stones, and provide for full safety against personal injury, even if large deformation damage on the tunnel itself is accepted. As indicated in fig. 12, the profile shows what is called a T8.5 tunnel. The hatched inner rectangle shows areas that are dedicated for vehicles. It is to be observed the large spare areas that are dedicated for deformation zones without entering into the vehicles area. A still larger zone is available if one can imagine deformations all the way to where people in a vehicle normally are located.

The solution with an optimal steel construction covered with a sturdy heavy gauge steel wire net will therefore be able to absorb large amounts of energy without collapsing. Each section is connected by steel wire in the longitudinal direction of the tunnel section such that the forces are distributed over a large area.

Such a construction is light enough to be transported by standard vehicles, and the costs involved is competitive relative to hillside securement or tunnel constructions made of concrete.

Deformed parts of a tunnel can be repaired with specially designed hydraulic repair tools to be operated inside the tunnel walls. In case of severe damages, complete tunnel sections can be replaced. In order to fold the tunnel construction, each tunnel section needs to be designed as an articulated mechanism that is secured by bolts when it is unfolded. These bolts are spring loaded, such that they automatically snap into engagement when they are positioned. This also entails a quick installation method without any elevated work in the tunnel space.

With reference to fig. 3, a schematic rear view of the open ended tunnel and lorry trailer 2a is shown. The temporary tunnel dome includes nested and folded elongated dome elements 6a, 6b, 6c. These dome elements 6a, 6b, 6c will be exposed when the dome construction is being unfolded.

As shown on fig. 3, the dome elements 6a, 6b, 6c comprises three elements folded into a triangular cross section internally of and in top of the elongated dome construction. The three elongated dome elements 6a, 6b, 6c are hinged together in their longitudinal direction. Even though three dome elements 6a,6b, 6c are shown in the figures, other numbers of dome elements are possible embodiments of the invention. As further shown in fig. 3, the elongated dome construction is made possible to erect by means of powered extendable means 7a, 7b, 7c, such as hydraulic cylinders. Any linear motor drive is conceivable, also pneumatic and electrically powered linear motors. Such linear motors can be inside telescoping beam structures, if not in open air. Other means for folding or unfolding the temporary tunnel than by the powered extendable means are however possible.

Other possible folding or unfolding (extendable) means could for instance be a scissor type jack.

The powered extendable means 7a, 7b, 7c are acting vertically and horizontally respectively, in order to elevate and unfold the three elongated dome elements 6a, 6b, 6c. In order to widely open up the tunnel cross section, the horizontally acting powered extendable means 7a, 7b are hinged together and used to widen out the road contacting parts 3a, 3b of the dome construction, while the vertically acting powered extendable means 7c is acting on the elongated dome elements 6a, 6b, 6c to push the triangle upwards and unfold.

Fig. 4 shows in perspective view the entire tunnel dome construction 1 unloaded from the trailer 2a of the lorry 2 (figure 3) and deployed on the ground or on a roadbed 10, which will be the normal procedure unless it is unloaded for storage at some location. The tunnel dome construction 1 is supported on the ground by the respective road contacting parts 3a, 3b, 3c, 3d, etc. to 3j. Fig. 5 shows a schematic rear view of the open ended tunnel shown in fig. 3, but with the lorry 2 and trailer 2a driven out of the tunnel dome 1 .

Fig. 6 and 7 show the tunnel dome construction where each pair of ground contacting supports 3a, 3b to 3i, 3j are fully brought apart and the tunnel dome construction 1 is prepared for next steps in order to be expanded to full scale tunnel profile. To this end, five pairs of horizontally acting powered extendable means are used, here represented by the first pair of powered extendable means 7a, 7b. As mentioned, each pair of powered extendable means 7a, 7b is hinged connected in one end, and hinged connected to respective ground contacting supports 3a, 3b to 3i, 3j in the opposite end.

Fig. 8 and 9 show the first step of tunnel dome erection into full profile tunnel dome 1 by use of five vertically acting powered extendable means, here represented by the first powered extendable means 7c. Each and every ground contacting supports 3a to 3j are firmly fixed to the ground by long rock bolts 9 driven through the road pavement and into the ground, preferably into solid rock.

Fig. 10 and 1 1 show the second step of tunnel expansion into the full profile tunnel dome. Continued use of the five vertically acting powered extendable means, represented by the first powered extendable means 7c, bring all the three elongated dome elements 6a, 6b, 6c into final position to complete the tunnel dome. The three hinged elongated tunnel sections 6a, 6b, 6c are locked together in this position by means of respective spring loaded lugs or bolts B that are snapped into engagement with holes or recesses.

Fig. 12 and 14 show the third and final step of tunnel expansion into full profile tunnel dome, where all tools are removed, and ready to for subsequent traffic use. As previously mentioned, and indicated in fig. 12, the profile shows what is called a T8.5 tunnel. The hatched inner rectangle R shows areas that are dedicated for vehicles. It is to be observed here the large spare areas Αι , A2, A3 that are dedicated for deformation zones without entering into the vehicles area R. A still larger zone is available if one can imagine deformations all the way to where people in a vehicle normally are located.

Fig. 13 shows two enlarged detail areas of the tunnel dome 1 . The upper one indicates the corrugated sheet metal plates P, while the lower one indicates the metal wire mesh M externally covering the sheet metal tunnel roof. Without being a limitation, a typical total length of the proposed tunnel, is 12 meter and 3 meter between each steel profiles 3.

Fig. 15 shows the deployed temporary tunnel being used by two meeting lorries, while fig. 16 shows a top and elevation view of same as in fig. 15, and fig. 17 shows an end view of two meeting lorries in a tunnel according to the present invention.

A procedure of installation is as follows:

1 . The tunnel section 1 is transported in folded position by lorry 2 having a low trailer 2a and height adjustable air suspension.

2. When the section 1 is in position, all the horizontal bottom beams 7a-7j are hydraulically telescoped to full width while the section 1 is still on the trailer 2a.

3. The section 1 is then put down on the ground, or roadbed, by descending the trailer 2a by operating the air suspension. Then the trailer 2a is removed.

4. Rock bolts 9 are installed through foot supports 3a-3j of the steel profiles 3. If the road describes a curb, the horizontal bottom beams 7a-7j can be used to force the tunnel section construction into a bend. Then temporary rock bolts need to be temporary installed in center.

5. The vertical hydraulic telescoping cylinders 7c then unfolds the three

elongated tunnel sections 6a, 6b, 6c until all the bolts has snapped into engagement by spring force.

6. Then the outer bolts of the horizontal telescopic bottom beam 7a-7j are released, such that these can be retracted hydraulically. The vertical telescopic cylinders are retracted and a lorry is driven in to remove these.

7. Now, next section is made ready for. This section is driven through the first section and is unfolded in the same way. Then the sections are interconnected by through running steel wires that are tied in.

There is no limit how long such a tunnel can be made.