EP2723987A2

EP2723987A2 - A method for constructing a tunnel course, and structural element for use by the method

Info

Publication number: EP2723987A2
Application number: EP12737622.6A
Authority: EP
Inventors: Torbjørn DALEGÅRDEN
Original assignee: Stabinor As
Current assignee: Stabinor As
Priority date: 2011-06-21
Filing date: 2012-06-21
Publication date: 2014-04-30
Also published as: WO2012177143A3; RU2014101625A; NO335669B1; WO2012177143A2; CN103748321A; CA2839485A1; NO20110892A1; US20150125215A1

Abstract

A method and a structural element for the construction of a directionally flexible and watertight tunnel lining (1) or tunnel course (1), the method using pre-fabricated elements of concrete or sandwich structure (3, 4, 5; 73;73'). Interspace between such elements and extending transversely of the direction of the tunnel course or tunnel lining receives an interspace cast (14) using an outer flexible formwork (2) in the form of skirts (2', 2'') attached to the outside of the elements (3, 4, 5; 73, 73'), and which through interconnection (11) thereof form a flexible, "bag-like" formwork (2) on the outside of the elements (3, 4, 5;73, 73'). Together with conventional formwork (12) on the inside of the elements (3, 4, 5;73, 73') there is formed a defined cavity (13) which can be filled with injectable mass of concrete. After the concrete has hardened it will provide support to the installed elements (3,4, 5; 73, 73') as well as providing support relative to exposed surface portion of rock surface (10). The elements (3, 4, 5; 73, 73') can be provided on the outside with a membrane (17). Further, the elements can be provided with injection paths (16) in order to at any time establish a completely watertight tunnel lining (1).

Description

A method for constructing a tunnel course, and structural element for use by the method.

The present invention relates to usage of pre-fabricated elements in a directionally flexible and watertight tunnel course for special or general use.

More specifically, the invention relates to a method for constructing tunnel courses which are completely or partly surrounded by rock formations and/or are located in open air, the tunnel course in its longitudinal direction consisting of a plurality of mutually separate, prefabricated, preferably tunnel arch forming structural elements which are intended to be sealed against each other or adjacent each other. Further, the invention relates to a structural element in order to apply the method.

Tunnel manufacturing technology is e.g. known from the following patent publications: EP 0.197.021, GB 2.068.894, US 4.895.480, DE 4.014.437 and DE 3.210.529.

Traditional or special solutions for establishing tunnel linings or tunnel courses have in most cases highly limited possibilities to fulfill all required specifications simultaneously as regards costs, life, tightness, safeguarding against rock avalanche etc.

Apart from tunnels having full-profile drilling made using tunnel boring machine (TBM), most tunnels are made using conventional drilling and blasting after adapted injection sealing of unbroken rock formations from so-called "tunnel face", followed by securing by means of rock bolts and sprayable concrete.

The configuration of the tunnel lining proper exhibits many variants. Concrete elements are known to be fixedly bolted at the sides with a variant of "umbrella" below the hang in the "ceiling", which could consist of a flexible insulating plate and which later proved to have short durability and be highly inflammable, have subsequently been attempted covered by sprayed concrete. It is however known that these repairs, in a time perspective, still have a very short life, and after a few tens of years most thereof is back to status quo. A

precondition for this and all other known methods is extensive securing works in the form of bolt-work and possibly use of sprayable concrete, because required inspection and status checking later is almost quite impossible to perform. Further, tunnel linings which include a movable material will represent an inherent risk, because the protective layer over time may crack due to fatigue and with the risk of dropdown or avalanche.

Tunnel courses which have been secured or made by means of sprayed concrete fall into approximately the same risk pattern. The method requires as an outset an almost watertight rock space after blasting operation, as it is challenging to spray concrete onto rock having water leaks. However, in present days technological situation related to sprayed concrete, the situation is such that this by itself is not sufficient for satisfactory tightness in the structure, but almost always requires additional safe-guarding measures against water and frost. Ongoing research related to sprayable membranes appears uncertain, and it is likely that the the complete "spraying method" also will be quite expensive. Constructing a safe tunnel lining by means of sprayable concrete is quite expensive and there are obvious limits to the amounts of fiber loaded concrete that can be applied, without triggering a requirement for more traditional reinforcement. Concrete in the context of tunnels is vulnerable due to leakages and bursting due to frost with subsequent disintegration of the concrete. Complete casting of a tunnel lining solves to a large extent requirements related to securing of rock, but have obvious weaknesses related to tightness and expenses. A non-reinforced, fully casted tunnel lining is highly vulnerable to leakages from formation of fissures and cracks due to quite often highly variable thickness of the tunnel lining, which yields large local stresses in the concrete resulting in cracking thereof. Repair thereof yields often an excessive demand for expensive injection sealing of the tunnel lining later. Reinforced tunnel lining is much more expensive, without any decisive guarantee against formations of fissures and unacceptable leakages through the concrete. Fully covering tunnel linings have also proved to exhibit substantial challenges. The sudden collapse of the ceiling of the Hanekleiv tunnel in the county of Vestfold, Norway some years ago is a typical example of how risky such a structure may be. Government authorities also emphasize that there are substantial problems related to inspecting the securing ofthe rock in these tunnels, both as regards accessability and a health hazard environment for the controlling personell.

An external membrane on the tunnel lining, also sometimes as multiple layers, as a foil between concrete and rock, presents a further turning of the screw of expenses. In addition, there is hardly any installation of membrane anywhere in the world which has solved the problems without a time-consuming and frustrating search for stray leakages.

In order to remedy the problem, it is these days attempted to establish complex injection systems by means of injection hoses to section the problems, which results in a wilderness of supply hoses which are likely difficult to administrate.

In addition, membrane entrepreneurs set substantial requirements to the smoothness and tightness of the surface, as welding membranes with water flowing likely is no wanted situation. There are present "patent pending" solutions for a continuous casting of a tunnel lining, which is usually named as sliding formwork, although the method is somewhat different. As far as known, none of these methods have been used in practise.

In summary, it is an obvious and common feature of all known methods today that the tunnel after blasting operations and before the next step, should be 100% secured and be almost watertight.

The present tunnel technologies therefore face numerous challenges, even though data controlled drilling rigs, sophisticated injection technique and fiber-reinforced spraying of concrete have improved the conditions substantially for different solutions related to tunnel linings of different types. Still, within the technology of tunnels there has in many aspects for a long time been a clear demand for novel considerations, for the purpose of solving all or most of the known problems. The expenses related to making tunnels are today prohibitively large due to a deficient relationship between the technical problems which arise and the practical solutions.

The present invention aims therefore to provide technical solutions which fully or partly solve the deficiencies, also by using known technique.

The method will prove to be highly cost efficient and the extent of today's expensive needs for securing by using installation of bolts, sprayable concrete and injection can be dramatically reduced. The tunnel lining as a structure will be almost maintenance free and exhibit an almost ever lasting life; 300 years or more.

According to the invention the method mentioned in the introduction is characterized by: a) installing along a tunnel course at each longituidinal side thereof tunnel element bases and cast these onto masses adjacent the bases, b) placing from recesses on the bases successively in the longitudinal direction of the tunnel course with mutual distance selfsupportive sections each consisting of at least two of said tunnel elements, wherein the tunnel elements are made of concrete or are of a sandwich structure,

c) arranging at the outside of the sections at the opening therebetween an outer, flexible formwork,

d) arranging formwork equpiment across the opening between the sections at the inside of the sections,

e) injecting concrete through the formwork equipment into a space defined by adjacent tunnel element sections, said outer flexible formwork and said formwork equipment, so that injected concrete expands the outer, flexible formwork outwardly and laterally at the outside of the tunnel course, and

f) letting the injected concrete harden. Further embodiments of the method appear from the sub-ordinate patent claims 2 - 15.

Said structual element as mentioned in the introduction is primarily characterized in that the element on the outside at each edge thereof which is transverse to the longitudinal direction of the tunnel course, is provided with a first outer flexible formwork half which is configured to be interconnected with a corresponding second outer flexible formwork half on a neighbouring further element when that further element is positioned next to said first element, to form a flexible formwork for receiving injectable concrete between the neighbouring structural elements.

Further embodiments related to this structural element appear from the sub-ordinate patent claims 17 - 25.

The invention is now to be described with reference to the attached drawings which exhibit non-limiting embodiments of the invention.

Fig. 1 illustrates characteristic use of an outer flexible formwork between arch elements and rock, or between base elements and rock.

Fig. 2 illustrates theoretical positions of the nets as the halves of the flexible formwork after the elements have been installed on their respective base elements. Fig. 3 illustrates interconnection of the halves of the flexible formwork at the outside of the elements and an inner traditional formwork provided with a casting assisting pipe stub.

Fig. 4 illustrates a primary interspace cast between elements and rock, and secondary casting between elements and rock.

Fig. 5 illustrates in vertical view a situation with interspace cast between elements and rock with varying mutual angle between some of the elements.

Fig. 6 illustrates in a horizontal view a situation with interspace cast between elements and rock with varying mutual angle between some of the elements. Fig. 7 illustrates an overall view of all structural elements including a cast tunnel foundation.

Fig. 8 illustrates a tunnel embodiment located on gravel/ rock in open air.

Fig. 9 shows a tunnel embodiment used for rehabilitation of existing tunnels having

foundation on different beds.

Fig. 10 illustrates a possible method in making tunnel linings having extensive cross-section. Fig. 11 illustrates in detail mounting of an element base, interspace mould and drainage pipe/ pipe for assisting casting.

Fig. 12 illustrates interconnection of formwork skirts and drainage pipe/ pipe for assisting casting.

Fig. 13 illustrates in a vertical section joint and interconnection of element bases having sealing.

Fig. 14 illustrates a horizontal section of joint and interconnection of element bases having sealing.

Fig. 15 illustrates detail of horizontal contact between element base having injection paths moulded therein, joint mat and tunnel element. Fig. 16 illustrates detail of horizontal contact between tunnel elements with inserted joint mat and injection path.

Fig. 17 illustrates in principle an infiltration cushion which is sectionwise dividable. Fig. 18 illustrates in principle a general and immediate sealing of joints using infiltration cushions and spreader mat.

Fig. 19 illustrates in principle two types of injectable joint packing.

Fig. 20a illustrates a grooved profile for formwork skirt part in a concrete element.

Fig. 20b illustrates in principle edge fitting fixedly pressed onto the edge of a net part.

Fig. 21a illustrates formwork skirt part with edge fitting established in a grooved profile.

Fig. 21b illustrates net part directly moulded into an element.

Fig. 22a illustrates establishment of formwork skirt part which has a membrane applied thereto.

Figure 22b illustrates formwork skirt part moulded into a concrete element with a membrane applied thereto.

Fig. 23 illustrates an installation situation for tunnel course elements.

Fig. 24 illustrates an inside curved formwork for interspace casting in a cavity between

elements and rock, and ventilation pipes at the upper hang-portion of the tunnel elements.

Fig. 25a illustrates an electrified smoothing jetty at operating positions upon executing a step of deploying smoothing- and structural concrete at the tunnel foundation.

Fig. 25b illustrates in principle individual drive units for a smoothing jetty resting on pivot pins.

Fig. 25c illustrates in principle embodiment of a tunnel foundation by means of "bulkheads".

Fig. 26 illustrates in principle anchoring of an electrified crane track.

Fig. 27 illustrates achoring and suspension in elements for a sectionally established crane track.

Fig. 28 illustrates tunnel elements of a sandwich structure in arranged position.

Fig. 29 illustrates tunnel elements of sandwich structure following complete casting operation using a flexible formwork. Fig. 1 illustrates the essence of the invention with all main components 1, 1', 2, 3, 3', 4, 4', 5, 5', 6, 6' 7, 7', 8, 9 included.

Although the invention will be mainly described related to tunnel arch forming elements made from concrete, it will be appreciated that such tunnel arch forming elements could instead be in the form of lightweight elements made as a sandwich structure, as shown and described in the context of the embodiments shown on Figs. 28 and 29.

Fig. 2 illustrates outer flexible skirt or formwork 2 which preferably can be in the form of interconnectable net parts 2', 2" which are each reliably attached in or along both vertical/ upright edges of the arch elements 3,4,5. In addition to the flexible formwork 2 having to possess the required strength against breakage related to the use in question, the mesh width of the net parts 2', 2" must be somewhat less than the largest diameter of the additives (stones) in the mass of concrete. This implies practical aspects in the context known as using a particular mass for sealing of cracks known as clotting mass, implying that after the largest particles in the concrete no longer can pass through a mesh opening, the continuously smaller particles in the concrete will come to a halt to finally block the entire passage, perhaps with the exception of leakage of water during a period. Such a flexible formwork 2 of nets 2', 2" will thereby act as a reliable formwork 2, provided the nets 2', 2" exhibit sufficient strength. The skirt, net parts 2', 2", 8, 9 can be made from alternative materials, synthetic thread (nylon etc.), organic material or steel wire etc. The flexible formwork, "the net bag" 2, may if desirable, be constructed from multiple layers with a heavy duty outer "bag" having large mesh width with an insert consisting of net material having less mesh width or from another material having corresponding properties.

Following interconnection 11 of the two net parts 2', 2" at the opening between the elements 3, 3' 4, 4' 5, 5' being adjacent in the tunnel direction, as shown in Figs.l and 3, and co-operative with a traditional inner formwork 12, there is formed a cavity 13 which upon injection therein of interspace mass in the form of concrete mass 14, see Fig. 4, will expand outwardly the flexible formwork or "bag" 2 until it contacts the exposed rock surface 10 and the concrete will thus subsequently to hardening provide a very advantageous support for the installed elements 3, 3' 4, 4', 5, 5' and masses of rock 10 along the entire cross-section of the tunnel. The formwork 2 simultanously ensures that the injected concrete is limited to the space of the cavity 13 and is not spread in non-controllable way behind the elements 3, 4, 5; 3', 4', 5'. Water leaking in through the rock surface 10 behind the formwork bag 2 during injection of concrete for establishing the interspace cast 14, will most likely after some wash-out of the concrete 14 at the front upon direct contact with the rock surface 10 be pressed laterally and represent a reduced risk for unacceptable amounts of binder agent in the interspace cast 14 being washed out.

Strong flows of water into the tunnel at locations where the interspace cast 14 is supposed to contact the rock surface 10, must in advance be sealed or guided away in a satisfactory manner, e.g. by by suspending plastic material on the rock surface 10 or let a suitable length of relatively rigid plastic foil, in the form of a roll of plastics fitted onto reinforcing steel bar, from the top side "roll downwardly" over the opening between the elements 3, 4 , 5; 3', 4', 5', whereafter the plastics can be attached at the upper end before the net parts 2, 2' are interconnected at 11. Simultaneously with the plastics foil being moved outwardly upon injection of the mass of concrete to form the interspace cast 14, it will protect the concrete against unwanted wash-out and guide leakages laterally, where the water in turn will disappear through drainage and casting assisting pipes 26, 26' (Fig. 11).

There is on Figs. 3 and 20a - 22b illustrated attachment 18, 18' of the net parts 2', 2".

Fig. 4 illustrates the situation after the primary interspace cast 14 has hardened and the mass of concrete has pressed the flexible formwork 2 outwardly towards the masses of rock 10. Further, there is shown a secondary cast 19 between the interspace casts 14, 14', the arch elements 3, 4, 5 and the masses of rock 10. As it also appears from Figs. 15, 16, 20, 21 and 22 there are shown the membranes 17, 17', 17" applied to the outside of the arch elements 3, 4, 5, recesses 15, 15', and injection paths 16, 16' moulded into the element edges which extend in a direction transversly of the tunnel course. It is obvious that the interspace cast 14 and its contact face with the arch elements 3, 4, 5 will be quite advantageous to obtain a completely water tight interconnection, also upon supply of sealing mass through the injection path 16, 16'.

The situation shown on Fig. 4 also confirms that the transition between the membrane 17, 17' applied to the outside of the arch elements 3, 4, 5; 3', 4', 5' and the interspace cast 14, is obviously quite close and solid and does not represent any uncertainty with respect to obtaining permanent tightness against water in the connection between the arch elements 3, 4, 5; 3', 4', 5' and the interspace cast 14. It can not be excluded that water may leak in through formation of fissures in the interspace cast 14, but that problem must be solved locally through injection and does not represent any significant deficiency of the method.

As shown on Figs. 5 and 6 it is possible, by placing a plurality of arch elements 3, 4 , 5; 3', 4', 5'; 3",4", 5"; 3"', 4"', 5"'; 3"", 4"", 5"" on the same base elements 6, 7, to enable the tunnel lining 1 to be turned both in vertical and horizontal planes. Upon change of direction in the horizontal plane as shown on Fig. 6, the length of one or both of the base elements 6, 7 is adapted so that the required radius of curvature of the tunnel course 1 is obtained, as indicated by the base elements or foundations 6, 6', 6", 6"' and 7, 7', 7", 7"'. It is preferable that the length of the base elements 6, 7 is adapted so that the distance between adjacent arch elements, e.g. elements 5, 5', along the center line of the tunnel always remains the same. The dimensions of the "wedge-shape" of the interspace cast 14 at the joints 23 of the base elements, may if required be varied based on what is possible in practice or structurally desirable. The width of the net parts 2', 2" will necessarily have to be adapted to the distance between neighbouring tunnel elements, e.g. elements 3, 4, 5; 3' 4', 5', which are located in the direction of the tunnel course.

In order that the method in addition may be adapted to seamless transition for cambering at curves, it will be advantageous that the top element 5 is not completely torsionally rigid, but to some extent may adapt itself to the side elements 3, 4 on which the top element 5 should rest. The elements 3,4 will necessarily get a different direction at their top, because opposed base elements 6,7 at respective sides of the tunnel course then will be located so that the free end of one base element 6 will be at a level different from the oppositely located base element 7. The top element 5, due to inherent elasticity in the element 5, will within certain limitations adapt itself to the top of the side elements 3,4. If this elasticity proves to be insufficient, it will in practise be possible to allow additional forces to force the elements 3, 4, 5 together at a joint 20 - 20"" between arch elements (see Fig.16) for thereafter permanently interconnecting the elements 3, 4, 5 by means of plates 84 - 84"' of steel moulded therein and connecting members 79, 79' welded thereto (as shown on Fig. 7) at a suitable distance from linear or radial edges of the arch elements 3,4,5.

Upon interconnection at the radial edges (not shown) of the elements 3, 4, 5, the

interconnection will with advantage be hided in the interspace cast 14. It is not likely that the elements, e.g. 3, 4, 5 will be structurally damaged by such a rough handling if the effect of applied forces lies well within pre-specified limits of tolerance. Even though the side elements 3,4 and the top elements 5 on their outside are covered by membrane 17 or have membrane 17 applied thereto, it will be appreciated that the membrane 17 will still be 100 % intact after such an adaptation.

In a method as indicated, the side edges of the elements 3 ,4, 5 will appear with a minor "stepping", but this is considered unproblematic, as these unevennesses are compensated by the inner formwork 12 and the interspace casts 14 - 14"".

A logic consequence of all of these conditions yields that the width of the interspace cast 14 may preferably also be varied to obtain different adavantages, as increased width provides a wider and stronger interspace cast 14 which will provide better support of the masses of rock 10, whereas a more narrow interspace cast 14 first of all will reduce the volume of concrete in the context in question. If the concept is complete casting, i.e. complete filling of the cavity with mass of concrete between the tunnel lining 1 and the rock surface 10, this plays mainly a minor role, except for the need for securing. Due to the nature of the invention, it will be unproblematic in the course of operation to reserve temporary open spaces in the tunnel lining 1 in order to later be able to install the missing elements 3, 4, 5, 6, 7 and establish the tunnel lining 1 as originally presupposed.

Further, it is of advantage that the elements 3, 4, 5; 3', 4', 5' can be manufactured with different radius of curvature or other preferred geometry, and that alternatives of concrete concepts can be used, as e.g. normal concrete, light-weight concrete, concrete with sintered particles, porous concrete etc. The structural strength and degree of reinforcement of the elements 3, 4, 5, 6, 7 are mainly related to the elements 3, 4, 5, 6, 7 being capable of handling from manufacturing to completed installation. Beyond this, some requirements will be that that a flexible formwork 2 is attachable to the outside of the arch elements 3, 4, 5 and that a membrane 17 can be applied to the outside. Further, Fig. 7 shows a tunnel lining 1, which contrary to prior art technology results in a completely watertight tunnel using only three different, pre-fabricated concrete elements 3, 4, 5, however so that different tunnel cross-sections will require arch elements with adapted radius of curvature.

The situation as clearly shown on Fig. 7, obviously creates possibilities for establishing a watertight tunnel foundation with membrane between a smoothing concrete layer 25 and structural concrete 28. Because the base elements 6, 7 will have very accurate mutual positions, it will as shown in Figs. 25a, 25b and 25c be of advantage to deploy smooting concrete 25 and structural concrete 28 by means of mechanical equipment in the form of an electrified smoothing jetty. "Concrete bulkheads" 89, 89' (as shown in Fig. 25c) are established at required mutual distance and preferably corresponding to an interspace cast 14 from cleaned rock surface 10 and up to top edge of completed structural concrete 28 of the foundation. There is placed between two bulkheads 89, 89' a smoothing drainage layer of coarse gravel 90 with a felt cloth 91 on top thereof and with drainage 92 through last bulkhead 89', whereafter smoothing concrete 25 is deployed by means of the smoothing jetty 58. A membrane 65 is placed or applied onto the smoothing concrete cast 25 between the bulkheads 89, 89' with a dedicated termination along the edges, or also with an injection path. After the structural concrete 28 has also been deployed and has been sufficiently hardened, the drain 92 through the bulkhead 89' is plugged, so that porous pressure behind the tunnel lining can increase. Further, it is preferable that the embodiment in question allows for establishment of a radial injection screen 95 through the bulkhead 89' and the interspace cast 14 out into the masses of rock 10 which surround the tunnel lining 1 to reduce linear movement of water therealong, without touching laid-in membranes. Further, as shown on Fig.7, it is advantageous that a plurality of watertight covering pipes (pulling- through pipes) 81, 81' can be established, located behind the tunnel lining 1 or be moulded also into the secondary cast 19 with radial projections 82, 82' through the interspace cast 14 at suitable distance. In case of fire or other serious incident, said establishment will be a very comforting safe-guarding of permanent installations or supplies in along the entire course of the tunnel 1, e.g. signalling cables, emergency lighting, frost- free water supply or the like.

The water tightening at the connection between structural concrete in the foundation 28, base element 6; 7, (see Figs. 7, 12 and 15), and interspace cast 24 between base 6; 7 and rock 10, can favourably be taken care of by injection through injection paths 16"", 16""' moulded into recess 15", 15"' on the element bases 6, 7 being present as a standard, even on both sides of the element base 6;7. It obviously also possible to establish an injection path (not shown) on the smoothing cast 25 closely adjacent the interspace cast 24 as a further injection option. As shown on Fig. 8, the method of the invention can without changes be used outdoors in open terrain as a tunnel for environmental purposes or for safe-guarding against effects of avalanches. The method is substantially the same as for a tunnel lining 1 inside a rock tunnel, but the installation of the elements 3, 4, 5, 6, 7 becomes much more simpler, as it can be made using a mobile crane. As shown on Figs. 11 and 12 there is established element bases 6, 7 as for a rock tunnel or by letting bolts 34, 34' for an anchoring tower 36, be located by means of depositing sufficiently large lumps of concrete mass at the joints 23, 23', 23", 23"' of the element bases 6, 6', 7, 7'. After the lumps of concrete have hardened, a top member 35 is levelled and is firmly welded to the bolts 34, 34'. The element bases 6; 7 can thereafter be landed onto the top member 35 and be laterally adjusted before fixedly welding thereof to the anchoring tower 36, 36' takes place via steel plates moulded into the bottom of the base 6; 7.

The support of the element bases 6, 7 relative to underlying terrain is preferably made using conventionally reinforced concrete which can either be filled around the element bases 6, 7 in a "ditch", in conventional formwork or against a flexible formwork 8, 9 attached at location 18 into the base elements 6,7. A precondition for establishing a tunnel course 1 in open terrain is obviously that the fundamentation takes place either on rocky ground or on compressed, not ground-frost- risky bed. When performing "free" casting using "the formwork bag" 2, it will when filled with concrete mass necessarily get a somewhat different cross-section outside the tunnel elements 3, 4, 5. From the element bases 6; 7 and further up along the tunnel arch, the cross-section will vary from a circular shape to a gradually more oval cross-section. This is however no problem, as the interspace cast 14 thereby becomes preferably more huge at the "root" of the tunnel lining 1 where the loads from any filling are the largest. If required, the interspace cast 14 can here, as inside a tunnel in rock, be reinforced more or less, but this must be assessed in each case. As for tunnel lining 1 in a tunnel in rock, the arch elements 3, 4, 5 have applied on the outside thereof a membrane 17 which is considered satisfactory.

Sealing of joints vertically and horizontallly between the tunnel elements can be executed as for the invention in general. In order to stabilize the arch elements 3, 4, 5; 3', 4', 5' until the interspace cast 14 has been made and has hardened, it will have to be considered whether the elements 3, 4, 5; 3', 4', 5' in addition must be supported by stays. An obvious

advantageous solution for stabilizing the elements 3, 4, 5; 3', 4', 5' would be to mould into these a plurality of steel plates on the inside along the elements 3, 4, 5 (see Fig. 8) adjacent linear or radial edges (not shown) and connect these with connecting means 79, 79' by means of welding. Upon rehabilitation of tunnels in general and in particular road tunnels, the invention can be implemented without extensive changes, as shown on Fig. 9. In principle, the element bases 6; 7 can be further used in a modified embodiment. A modified, low element base 29, 29' is fixedly bolted to the foundation through a recessed position from the bottom of the "bearing" 22, 22' (Fig. 11) and is established for each arch section 3, 4, 5. This may be of advantage for continously following the tunnel path. The modified base 29, 29' for the arch can be placed on existing edge guides or on other bedding along the sides of the tunnel course. It may be considered whether there must be installed a plurality of rock bolts 31, 31' via the interspace cast 14 to safeguard against any risk for subsequent slide-out at the lower edge of the tunnel lining 1. In addtion, all installations of the arch elements 3, 4, 5; 3', 4', 5' and the cast 14 are made as described for the invention in general.

Crane track 68 with stay bolts 67, 67' for the crane rail and associated threaded casings 30, 30' for the bolts 67, 67' can be installed, and an advantageous formwork structure 12 can enable that the tunnel can be kept open for adapted traffic over prolonged periods of the day. Fig. 10 elucidates a method for tunnels having an extra large cross-section. By positioning and make interspace casting 14 to (modified) arch elements 3, 3'; 4, 4' using anchoring in the form of rock bolts 31, 31' to rock via the interspace casts 14, 14', the elements 3, 4 at either side of the tunnel course can be stabilized and form a kind of foundation for the subsequent installation and interspace casting 14 of (modified) top elements 5, 5'. Fig. 11 shows a section of the "free end" of the element base 6,7 attached to rock 10 via strong, fixedly fitted bolts 34, 34'. The bolts 34, 34' are fixedly fitted inclined towards each other and are, as mentioned earlier, interconnected with a top member 35 in the form of a heavy duty flat metal piece welded to the bolts 34, 34' after the top member 35 has been levelled into its individual position. The tolerance related to the positioning of the rock bolts 34, 34' in the longitudinal direction of the tunnel course must be such that the plate 33 which has been firmly moulded into the lower region of the element base 6,7 corresponds with and can be welded to the top member 35 which is mounted on the bolts 34, 34'. On the opposite "locked" end of the base 6; 7 there is fixedly welded two strong supportive fittings 37, 37' in the form of flat members on edge onto steel plates 32, 32' which are moulded into the top of the bases 6; 7, such that half of the length of the fittings 37, 37' protrudes out from the end of the base 6; 7. After landing of the base element 6; 7 on an established anchoring tower 36 for the base and the end of previous base 6; 7 and after aligning laterally, the fittings 37; 37' are fixedly welded onto the steel plates 32, 32' which have been moulded into the top of the base 6, 7 and there is also welded between the anchoring tower 36 and steel plate 33 moulded into the lower part of the base 6, see also Fig. 13. It will be appreciated that the base elements 6; 7 should, in a convential manner be provided transversely and along their entire length with reinforcement, and as indicated by reference numeral 39".

Due to the favourable flexible formwork 8; 9, see Figs. 1 and 12, concrete mass can immediately be supplied between base element 6; 7 and rock 10 nearby. The net 8; 9 must necessarily be somewhat longer at both ends than the very base element 6; 7 and must on both sides be located and attached such that mass of concrete does not flow out at the ends of the base 6; 7. This implies that the net 8; 9 at the free end of the base 6; 7 must be moved up to and be attached to the upper and outer edge of the base element 6; 7 for thereafter to be taken to the face of the rock 10 and fixedly attached thereat by bolting in a satisfactory manner. This can be performed in a favourable way in that simultanously with other welding operations, there is welded a "loop" onto the steel plates 32; 37 on the outer edges of the base elements 6; 7 where the individual interspace cast 24 is to be terminated. The edge of the net part 8; 9 is hooked onto the loops and led from the uppermost located one over to the rock surface 10 and fixedly bolted thereat. At a location where multiple element bases 6, 6', 6", 6"'... are to be moulded into the interspace cast 24, 24', 24"... simultaneously, the ends of the net parts 8, 8', 8", 8"' are attached together transversly of the longitudinal direction of the tunnel course in satisfactory manner and will thus form a continuous flexible formwork 8; 9. Before making an interspace cast 24 between base element 6; 7 and exposed rock surface 10, it is necessary to deploy the nets 8; 9 up along the rock surface 10 and if necessary attach the nets 8; 9 to the rock surface 10 at a plurality of locations by means of pegs 66, if there is a risk for the mass of concrete to "brush away" the nets 8; 9 before mass of concrete in fact has landed on the nets 8; 9 and loaded these nets. The friction between the nets 8; 9 loaded by mass of concrete and the rock surface 10 will soon stop the movement of the nets 8; 9 down the rock surface 10 and mass of concrete can be supplied to a desirable level, which should lie somewhat below the top of the base element 6; 7. An obvious precondition is that the width of the net parts 8; 9 is sufficient, and the width of the net parts 8; 9 should in general be calculated from the attachment 18' of the net parts 8; 9, vertically down to the rock surface 10 and up along that surface to a height at the upper edge of the base 6; 7. Around the legs 34, 34' of the achoring tower 36, the net parts 8; 9 must be split for subsequently to be joined together again in a sufficient way, or that the net parts 8; 9 are interconnected around the legs 34, 34' of the anchoring tower 36 where the net parts 8, 8', 8"; 9, 9', 9"...

continuously continue.

It may be favorable in order to limit the use of net material 8; 9, and to make a safe and predictable cast work 24 between the base elements 6; 7 and the rock 10, systematically to insert a plurality of "pegs" 66 in the rock surface 10 before the base elements 6; 7 are installed. The pegs 66 can favourably consist of short pieces of reinforcement steel bars which are put down into angled holes drilled a short distance into the rock surface 10. After the base elements 6; 7 have been installed, the net parts 8; 9 are deployed up along the rock surface 10 and firmly hooked onto the plurality of pegs 66, ... which are located in the direction of the tunnel course at suitable distance from the upper edge of the net parts 8; 9. In practice, it may prove advantageous that the drainage pipe/ the casting assisting pipes 26 are led through adapted holes in the net 8, 9 and clamped to the rock surface 10 at their top, the end of the pipes being at sufficient height and possibly temporarily closed off. After completion of the cast 24 the pipes 26 can immediately be opened or be cut to possibly lead away unwanted water flowing down onto the cast concrete 24. The pipes 26 are in any case later to be cut down so that they coincide with the upper face of the interspace cast 24, and so that leakage water from the rock surface 10 down onto the interspace cast 24 is guided away via the pipes 26 - 26"'.

The drainage pipes 26 - 26"' should be dimensioned so strong that they later and without problems can function as casting assisting pipes upon connection to and injection of mass of concrete between the cast 24, 24' related to the base, the interspace cast 14, 14' and the arch elements 3, 4, 5; 3', 4', 5'

If the cavity between the arch elements 3,4,5 and the masses of rock 10 is to be filled completely with mass of concrete, this must necessarily take place while the drainage-/ casting assisting pipes 26 are available from the inside of the tunnel, i.e. before the tunnel foundation 25, 28 is established. In order to ease the making of the cast 24 between the base elements 6; 7 and rock 10, it may be advantageous to arrange a wide and funnel shaped channel of concrete with rollers (not shown) and which is pulled on the edge of the base element 6; 7 to minimize spillage of concrete and to control the path of the concrete down closely adjacent the lower edge of the base 6; 7. In any case, the top of the base 6; 7 and the bearing 22 in the base element is cleaned and is possibly washed with water while the concrete is fresh. If mass of concrete from the interspace cast 24 or the net 8; 9 is found on the end of the last base element 6; 7, it must be removed completely before the next base element 6; 7 is brought into position.

Advantageously, the invention permits that there can be installed many pre-fabricated base elements 6; 7 successively and that the cast 24 which secures the base elements 6, 7 firmly to neighbouring masses of rock 10 can be made without any need whatsoever for

conventional formwork, in view of instead using the nets 8; 9.

Further details shown on the section (see also Fig. 15) is "the bearing" 22 for tunnel elements 3; 4 in the base 6; 7. The bearing 22 has semi-circular cross-section, and the centre of the bearing 22 can be a somewhat lowered relative to the top of the elements 6; 7 and with tangentially opposite differing sides, something which permits that the tunnel element 3; 4 with its semi-circular shaped lower end can be tilted a few angular degrees, implying that the arch elements 3; 4 can be moved forwards and backwards at the top of the elements 3, 4 . The radius of curvature of the bearing 22 for the base element 6, 7 must necessarily be somewhat larger than the radius of curvature of the bottom of arch element 3, 4.

On Fig. 12 is shown a vertical view of element bases 6, 6' and the positioning of arch elements 3, 3'; 5, 5' onto these bases 6, 6'. The length of the element base 6; 7 can vary, but it is in general of advantage that the length of the base 6; 7 is adapted to the width of the element, so that it is preferably obtained same distance between the elements 3, 4, 5; 3', 4', 5'. All individual elements 3, 4, 5, 6, 7; 3', 4', 5', 6', 7' are normally made identical, so that all in principle can be used interchangeably in end reversed position (see also Fig. 1). The width of the interspace cast 14 can be adapted to the need for space upon interconnection 11 of the nets 2', 2" or be increased beyond this to establish an extra strong interspace cast 14 for securing the masses of rock 10. If it calculationwise or based on experience proves necessary to prevent lateral slide-out of the arch elements 3, 4, 5 by injection of concrete mass for the cast 14, there can favourably be placed one or more two-piece anchoring bolts 38, 38' from threaded casings fixedly moulded in the elements 3, 4; 3', 4', and which later are welded together at location 38". On the vertical view there is further illustrated interconnection 11 of the neighbouring net parts 2', 2" which together will constitute the flexible formwork "bag" 2. Due to the obvious situation in the opening between the arch elements 3, 3'; 4, 4'; 5, 5' and the net parts 2', 2", it will be favourable to pull the net parts 2', 2" in through the opening between the elements 3, 3'; 4, 4'; 5, 5', place the net parts 2', 2" against each other as shown on Fig. 3 and bind the net parts 2', 2" together at that position to create the interconnection 11.

However, it will be obvious that the net parts 2', 2" can be joined together even though the the distance between the elements 3, 3'; 4, 4'; 5, 5' is quite small and the limit is apparently in that it becomes practically possible to inject concrete for the interspace cast 14. After the net bag 2 has been put back between the elements 3, 3'; 4, 4'; 5, 5', the formwork 12 can be positioned and the making of the interspace cast 14 can take place.

The interconnection 11 can obviously be solved through alternative methods, but the preferred one is to "sew" together the net parts 2', 2" by means of e.g. steel wire 11 or other interconnection means, which is of the same length or somewhat longer than the total length of the net parts 2'; 2". Onto the end of the steel wire 11 can be fitted a needle of suitable length, and the wire 11 can likely favourably be threaded through the net parts 2', 2" from the top of the arch and downwards at both sides, by letting the wire 11 run over a pulley (not shown) temporarily hung onto the edge of the top element 5, 5'.

After interconnection of the net parts 2, 2' in the opening between the arch elements 3, 4, 5; 3', 4', 5', the respective ends of the wire 11 must be anchored in the respective base elements 6; 7 in that it is as a standard procedure made an minor cut-out or "loop" 43 at the middle of the members 37 (see Figs. 12, 13 and 14) where the wire 11 can be pulled through and be secured, or directly be interconnected about the supportive, fitting members 37.

Midway in on the base element 6, 7, the wire 11 can be anchored in the same manner by fixedly welding a supportive member 37 to a steel plate 85 moulded into the top of the base 6, 7. Alternatively, there can be fixedly welded a loop (not shown) to that same plate 85 where the wire can be anchored in a safe way. Independent of how the wire 11 is anchored, it is very important that the net parts 2', 2" are joined in such a manner that there is created a tight "bottom" in the formwork bag 2 completely in towards the outer faces of the arch elements 3, 3'; 4, 4' and that it is shaped so that the "bottom" of the bag 2 may rest on the top of the interspace cast 24.

Transverse joining interconnection 86 (see Fig. 8) of the edges of the net parts 2', 2"; 2"', 2"" in the direction of the tunnel course can also take place through alternative methods, also using wire, but the currently preferred best mode will be to hook together the created net type flexible formworks 2 using "closed" loops of steel which are so spacy that some required net material can be accomodated within the loop. Due to the location of the transverse joints 86 in height direction considered, the stress on the net-based formwork 2 during injection of concrete mass for the interspace cast 14 will here be far less than the stress at the bottom of the net bag 2 resting on the interspace cast 24.

In the base elements 6, 7 there must be included embedded articles having specific tasks. In the bottom of the base 6; 7 there must, as previously indicated, be embedded (moulded in) sufficiently large and anchored plates 33, 33' of steel at the ends of the base 6; 7, as well as embedding (moulding in) at the top and ends of the base 6; 7 the previosly mentioned plates of steel 32, 32', 32", 32"'. At the mid region and top of the bases 6, 7 there must be embedded (moulded in) plates 85, 85' of steel for firmly welding of a heavy duty slab or flat member on edge corresponding to supportive member 37 as bedding for the foot of the curved formwork 12 and pivot bearing 55. Further, it must be moulded into the bottom of the base element 6; 7 a recess profile 39' for attachment of said skirts 8; 9, as will be more closely explained. Even though all embedded (moulded-in) units are not used in each installation situation, it will be quite advantageous that the base elements 6, 7 are symmetric about both axes of the base elements 6, 7. This yields much better flexibility, because fitting 18' of the net parts 8, 9 and the steel plates 32, 32' on the top of the base elements 6, 7 for establishing of a fitting for the foot of the curved formwork 12, will not require any attention and control before the base elements 6, 7 must be directionally oriented before transport into the tunnel course, as the length of the elements 6, 7 in some cases possibly does not permit a turnaround of the elements 6, 7 inside the tunnel course.

The element bases 6,7 can with advantage be moulded and transported "upside-down", preferably with lowered lifting devices (not shown) moulded into the underside of the element bases 6,7, as this will also ease storage of the elements 6, 7. This is also preferable because this must necessarily be the position of the element 6; 7 when the formwork skirt/ net 8; 9 is to be fixedly inserted at attachment location 18. The net 8, 9 to be used for fixing the element base 6; 7 through use of the interspace cast 24, may have far less strength against breakage than the net parts 2', 2" associated with the arch elements 3, 4, 5; 3', 4', 5' and the attachment 18' in the base elements 6, 7 can likely be made using a rapid hardening, expanding mortar.

If the base joints 23 - 23"' are to be completely watertight, then there is in Figs. 13 and 14 shown a favourable method, in that both ends of the base elements 6, 7; 6', 7' during manufacturing are made with a "shallow" semicircular recess 41, 41' for a sealing plug 42 downwards towards the bottom of the element 6, 7, so that when two base elements 6, 6' are joined together, there is formed a cavity having a "bottom". The joint 23 between the element bases 6, 6' can thus advantageously be sealed by filling of expanding mortar or e.g. liquid asphalt which forms the sealing plug 42. It will be advantageous to install a self- adhesive packing of foamed rubber or rubber on an end of the base elements 6, 7 and around the recess 41 immediately before locating a new base element 6, 7, in order to prevent sealing mass forming the plug 42 from leaking out from the cavity.

As shown on Fig. 16, all joints 20 in the direction of the tunnel course and located between arch elements 3, 4, 5 are favourably provided with injection paths 16"' moulded into the elements 3, 4, 5 and which can be injected with a suitable sealing mass as may be required. Correspondingly, for joints between interspace cast 14 and adjacent elements 3, 4, 5; 3', 4', 5' there may in the elements be provided moulded- in injection paths 16; 16' which can be injected with suitable sealing mass as may be required. Injection paths 16" for injection of sealing mass as may be required can be present in the bases between elements 3, 4; 3', 4' and adjacent base 6, 7; 6', 7'.

In Fig. 15 is also shown an open-pore, compressible and injectable "joint mat" 44 which is located in the connection between the arch elements 3; 4 and the base 6; 7, and in Fig. 16 is shown a corresponding "joint mat" 44' at the connection between the arch elements 4; 5. By means of these it is achieved that the sealing material is "reinforced" and in practise will appear as an on-location moulded packing having long life. A cheap and efficient joint mat 44, 44' , as e.g. shown Figs. 18 and 19, can e.g. consist of mineral wool , glass wool or the like (Rockwool ®, Glava®, etc.).

Alternatively, the sealing between sections of the arch elements 3, 4, 5 and/ or arch element 3; 4 and base 6; 7 can consist of a closed-pore, compressible plate 45 having through-going perforations (as shown on Fig. 19), which also due to the perforations will be injectable because sealing mass favourably upon any injection can spread to both contact faces via the perforations. Such a "joint packing" 45, 45', as indicated on Figs. 18 and 19, can e.g. be a flexible plate of closed-pore cellular rubber or of plastics with through-going perforations. The joint package 45, 45' should primarily be watertight after installation of the elements 3, 4, 5, but can also be further sealed via the respective injection paths 16"; 16"' in sides of the elements 6, 7; 3, 4 extending in the direction of the tunnel course, i.e.. "linear" sides.

As shown on Figs. 11, 15 and 16 it will, due to relatively short lengths of the injection paths 16" - 16""' be likely that the injection paths can be injected via supply hoses 77 - 77"' which have been installed at the middle of the hose sections via a T-piece and which thereafter are led to the air side (tunnel course side) of the elements 3, 4, 5, 6, 7 and are terminated inside a lid provided plastic cup 78 - 78"' moulded into the elements and which later is exposed in the surface of the concrete. The supply hoses 77 - 77"' can favourably be arranged as shown on the cross-sections and are easily secured during the process of moulding by attachment to the reinforcement in the element.

If the injection paths 16"- 16""' are to be re-injectable, then supply hoses 77 - 77"' must be established at both ends of the respective injection path 16" - 16"" and led to the air side (inside) of all elements 3, 4, 5, 6, 7.

Corresponding solution with supply hoses and plastic cup can correspondingly be provided for the injection path 16; 16' on those edges of the elements 3, 4, 5 which are oriented transversely of the tunnel course.

A method for immediate water tightening of the element connections 20, 21 as shown on Figs. 17, 18 and 19, is the introduction of "infiltration cushions" 46, 46' containing a single- component sealing material (Polyurethane (PUR) or the like) which is placed below or above the "joint mat" 44, 44' and which will crack and release adapted and sufficient amount of sealing mass as soon as the arch elements 3, 4, 5 are lowered into position. The mat 44, 44' will thus function like a "wick" which attracts sealing mass and yields an almost immediate sealing as the sealing mass over time is exposed to moisture. By fixedly gluing a suitable package 47, 47' or by using a self-adhesive version in the region of the edge of the element 3, 4, 5, the sealing mass will efficiently be held in place without flowing out in axial direction. Injection paths 16 - 16"" for injectable sealing mass should still be implemented in the elements 3, 4, 5, 6, 7 as indicated to ensure an absolute possibility for supplemental tightening in a rational fashion at any time. The infiltration cushions 46, 46' (see Figs. 17 and 18) can be manufactured in a favourable plastics quality, possibly chemically degradeable in the operative environment in question, provided in suitable lengths with a short and empty inter-space 46", so that the array of infiltration cushions 46, 46' can be cut away from each other and be adapted to lengths in question.

The superior object of locating a joint mat 44, 44' or joint packing 45, 45' is to make the joints 20, 21 between the elements 3, 5; 4, 5; 3, 6; 4, 7 as compact as possible and simultaneously optimum injectable in that the sealing mass is reinforced and is also favourably spreadable in the entire width and length of the joint 20, 21.

The requirement related to the technical properties of the injection path 16, 16' (see Fig. 4), is that it primarily can withstand the outside water pressure which will arise in the mass of concrete of the interspace cast 14 when concrete mass is injected into the cavity 13, without the injection path 16, 16' being infiltrated or damaged in the course of the process. It is also important that the injection path/ injection hose 16 , 16' has such a cross-section and surface structure that the injection path 16, 16' can get a good grip in the concrete surface and be satisfactory exposed to the surroundings.

Stabinor AS, Lier, Norway manufactures an injection hose which meets, by a good margin, all requirements in question related to such devices. Tests made in pressure chamber confirm that the injection hose resists an external water pressure of 5 - 6 bars without the injection hose being infiltrated by water in the chamber. The injection paths 16 - 16" " ' must by means of suitable devices be attached/ installed on the formwork parts without the hose being affected in negative way when the formworks are disassembled. The net parts 2', 2"; 8, 9 can be attached in alternative ways, also purely mechanical. Figs. 20a - 22b illustrate a method for safe attachment fitting 18 of the formwork skirts / net parts 2', 2' at the edges of the arch elements 3, 4, 5 and which distributes the stresses on the net parts 2, 2"; 8; 9 at the attachment fitting 18 in an excellent way. As shown on Fig. 20a there is established a profile 39 of plastics or sheet metal at sufficient distance from the edges of the elements 3, 4, 5; 6, 7 (see also Fig. 11). With a profile 39 made with favourable cross-section, the method may further imply that there is at the construction site made a casting in place at location 18 of the edge of the net parts 2', 2" by means of a strong, rapid hardening mortar. By fixedly pressing into position shortened lengths of edge fitting 94, 94', 94"... on longitudinal edges of the net parts 2'; 2", more easily a positioning and securing can be made. By turning the edge fitting "upside down", the net parts 2'; 2" can be pulled into the recess-profile 39 from the end, whereafter the edge of the net is retained in the profile 39 because the width of the profile does not allow the edge fitting 94 to rotate back to original position. It is also advantageous that the strength and the width of the skirt 2', 2" can be adapted to on-site conditions in order to avoid excessive use of net material. The moulding into place 18 of the net parts 2', 2" should be made with the net parts 2', 2" in the same position as shown on Fig. 21a, because the net parts 2', 2" then will be in almost the same position as when executing the interspace cast 14 (see Fig. 4). In a smaller recess 40 for the net parts 2', 2" at the end of the recess profile 39, the net parts 2', 2'; 2", 2" can be pulled inwardly towards the tunnel course upon the installation of the arch elements 3, 4,

5, so that the nets 2', 2" as such will not represent any bar against the contact between the arch elements 3, 5; 4, 5. As shown on Figs.21b and 22b, the net parts 2'; 2" and 8; 9 can be moulded directly into the arch elements 3, 4, 5 and the bases 6, 7 (not shown). Even in this situation it may be advantageous that the net is provided with edge fitting 94 as the net more easily can be distributed correctly over the length and be attached.

A corresponding solution, such as shown on Fig. 11, is available for attachment 18' of the net parts 8; 9 at the lower edge of the bases 6, 7. Thus, there must be established a recess 40' at the termination of the recess profile 39' which at the lower edges of the base element

6, 7 is moulded therein.

Further, the drawing figures (see also Figs. 2, 3, 4, 15 and 16) illustrate that at a suitable point of time in the process, i.e. after moulding the arch elements 3, 4, 5; 3', 4', 5', but before installing these in the tunnel course, a membrane 17 is applied to their outside. The membrane 17 may be a sprayable or smearable membrane or a method may be used where a membrane cloth is tacked to the surface of the element, possibly using a sprayable or smearable membrane as glue. At a location where it is made a contacting cast between the arch elements 3, 4, 5, the interspace casts 14, 14', the interspace cast 24 and the rock surface 10, the membrane 17 will obviously be tightly surrounded by concrete on both sides and quite well protected, with a life only limited by the properties of the membrane material as such. The elements 3, 4, 5; 3', 4', 5' may if desirable, also in advance, get an inner coating or paint applied, which after cleaning of the concrete surface can obtain good adhesion and life duration, and ease cleaning and reduce carbonatisation of the concrete, although this in the context is less important as the reinforcement in the arch elements 3, 4, 5 after completion of the tunnel lining 1 has reduced importance and in addition has large coverage.

Fig. 23 illustrates a typical installation situation for the arch elements 3, 4, 5. After the arch elements 3, 4, 5 in a satisfactory manner have been moved into the installation area, they are handled by an installation machinery 52 provided with vacuum equipment 51, e,g. vacuum plate, which connects to, can lift and support all loads in question at all positions. The side elenents 3, 4 are installed first and are supported temporarily by raising from the tunnel bottom one or more supports 48, 48' using an incorporated hydraulic jack having short stroke - for safety reasons - to an articulated transition on a self-locking "grip shoe" 49 which is entered on the elements 3, 4 from the edge thereof. After both side elements 3, 4 have been positioned and supported at their respective "spreaded" positions, there is applied to the top element 5 from the edge thereof a plurality of self-locking "guide shoes" 50, 50' which are attached to the element 5 by means of set screws. The top element 5 (constituting a locking element) is thereafter brought up to a suitable position between the side elements 3, 4. The side elements 3, 4 are thereafter by slight turning lowered down onto the guide shoes 50, 50' and most of all weight or all weight from the side elements 3, 4 is transfered to the guide shoes 50, 50' , whereafter the installation machinery 52 lowers all elements 3, 4, 5 slightly and simultaneously into final position, in order that these elements find their mutual self-centerering contact faces and form a satisfactory stable selfsupportive entity, whereafter the guide shoes 50, 50' should be removed prior to making the interspace cast 14 and the interspace cast 19 to form a final tunnel lining 1. In the course of the installation process a possible positioning of the joint mat 44, the infiltration cushion 46 or joint package 45 must take place in a practical and acceptable manner.

After the elements 3, 4, 5 have assumed their final positions, the elements 3, 4, 5 jointly form a satisfactory stable structure until the interspace cast 14 has been made. The elements 3, 4, 5 do not have particularly much space for larger movements until the time for the interspace cast 14, but the elements 3, 4, 5 may in a simple manner by using wood material be blocked up against the rock surface 10 behind the attachment 18 of the net parts 2, 2'.

Thereafter, it is ready for interconnection 11 of the flexible net parts 2', 2" and installation of the inside formwork 12. If the elements 3, 4, 5 in practise do not obtain completely accurate mutual position in the longitudinal direction of the tunnel course, this has reduced importance as the formwork will cover sufficient area for making the interspace cast 14.

The installation machinery 52 for the arch elements 3, 4, 5 can preferably be movable on wheels, with a short and strong telescopic arm having rotation and tilt properties and a quick-coupling for attachment of the vacuum equipment 51 which connects to the arch elements 3, 4, 5. The installation machinery 52 may advantageously be placed on a three- axis frame controlled dumper chassis (not shown) with hydraulic supporting members for use when connecting to the elements 3, 4, 5 and/or during the installation phase. Further, the chassis should be utilised in such a way that there at the sides or at the rear can be arranged a "cradle" where the elements 3, 4, 5 can be provided with support during movement. Upon deconnection of the vacuum equipment 51, the installation machinery 52 may favourably also be used for other tasks with suitable equipment using the quick-coupling.

Figs. 3 and 24, also with some structural details, illustrate in principle the inside formwork 12 which can favourably be made as a light, two-part, dividable and hinged framework structure which is fully or partly self-erectable by means of pneumatic cylinders 54, 54' which through advantageous use also can erect the curved formworks 12, 12' during the first phase of the installation. The curved formworks 12, 12' are catched manually at the top and are connected by means of one or preferably two hydraulic tensioning devices 53, 53' and which after applied tension are also secured in a mechanical way. The obvious advantage of using two separate tensioning devices 53, 53' is that the tensioning forces thereby can be directed directly into the bottom booms on both sides of the framework of the curved formworks 12, 12'.

The foot of the curved formwork 12 may favourably be provided as a pivotal bearing 55, 55' having its base on existing fixedly welded supportive members 37, 37' at the joint 23 of the element base 6, 7; 6', 7' or to be attached "supportive members" 37", 37"' welded onto steel plates 32 at the middle of the base 6, 7. The supportive members 37, 37', 37" will in addition have an accurate positioning and will together with the moulded-in steel plates 32, 32', 32"... at the top of the bases 6, 7 straight away carry the loads which the tensioning of the formwork 12 yields.

Further, it is advantageous that the lower part of the formwork 12, 56; 12', 56' with concrete supply stub 80, 80' are separate and independently installable and uninstallable towards the outside of the curved formwork. It will ease the releasing of the formwork 12, 12' if the stub 80, 80' with surrounding formwork plate 56, 56' can be released from the curved formwork 12, 12', and remain sitting on the concrete surface when the curved formworks 12, 12' are lowered. In such a manner, the formwork plates 56, 56' can be detached later and thereafter be installed back on the curved formworks 12, 12' before the curved formworks 12, 12' are erected the next time.

The formwork skin on the curved formworks 12, 12' may preferably be made from a light and strong material having a replaceable coating on the outside. The method may presuppose that a plurality of pairs of curved formworks 12 are available, so that longer sections of the tunnel advantageously can simultanously be provided with interspace casts 14. The formworks 12, 12' may favourably be moved directly to next location or be stored in folded configuration.

In order that contacting cast 19, see Figs. 4 and 29, between arch elements 3, 4, 5 and rock surface 10 can be made in a predictable and good manner, it will be advantageous to install a plurality of pipes 57 - 57"... at the top of the "hang" behind the interspace cast 14 for evacuation of water and air when making the interspace cast 19. The pipes 57 - 57"... may favourably have an internal diameter in such a manner that added material in the concrete of the interspace cast 19 after a short time automatically will block the pipes 57 - 57"...when the concrete of the interspace cast 19 reaches the top.

Due to the obvious possibilities offered by the invention to establish a tunnel lining 1 with a high degree of accuracy, also between opposite element bases 6, 7, it will be advantageous to develop mechanical equipment for smoothing the tunnel foundation 25, 28 (see Fig. 7) where it is to be cast and preferably be watertight. As shown in Figs. 25a, 25b and 25c the equipment can comprise electrically powered units 60, 60' with drive wheels 59, 59' which carry a smoothing jetty 58 running on rollers 93 within a steel profile 94 bolted onto supportive members 37 on edges of the element bases 6, 7. The propulsion can with advantage take place using a gear interacting with a rack attached to the upper side of the steel profile 94 or through a rubber coated wheel having spring tensioning. The jetty 58 can advantageously be built as a framework structure as depicted by Fig. 25a. By giving the carriage (jetty) 58 independent propulsion from the motors 60, 60' and arrange the smooting jetty 58 on pivot pins 61, 61' at both sides, it will be maneuvreable safely on the edges of the base elements 6, 7, even at curves and at inclinations, in that the jetty 58 normally will not possess total torsional rigidity and also can be granted a certain lateral staggering tolerance. By providing the jetty 58 with a plurality of movable, inclined and adjustable "wings" or articulated transport screws (not shown), a variable, vibrating "smoothing board" 87 can be attached to rubber dampers at the side of the bottom boom 88 of the jetty 58. The concrete for the foundation 25, 28 will thus be able to be transported outwards and up at the sides with reduced need for manual handling. The smoothing jetty 58 can be adapted to level of the smoothing cast 25 and the structural concrete 28, respectively, by moving the jetty 58 in vertical direction via an adjustable device which also by means of a slide could be operated in stepless fashion via a motorized spindle. When the smooting jetty 58 is not used, it may be released from the pivot pins 61, 61', be lifted and placed along the tunnel lining 1, while the propulsion units 60, 60' can still remain on the edges of the base elements 6, 7. If there favourably has been installed a crane track 68 in the tunnel course, it will at the time for casting of the foundation be operative and could be used for immediate

displacement of the smoothing jetty 58. The crane track 68 can also advantageously be used in connection with casting of the foundation 25, 28, e.g. by one or more travelling carriages 69, 69'.. by "loose" rollers (not shown) hooked onto the crane rail 68, keeping up and continously allowing to position the injection hose for concrete from above and downwards right in front of the front of the smoothing jetty 58, also by being able to move the injection hose laterally out to the sides and contribute to placing the concrete in a precise manner over the entire width of the bottom of the tunnel. The logistics related to transporting elements 3, 4, 5, 6, 7 into the tunnel, can as regards the element bases 6, 7 be solved through transporting therein and deploying by means of a crane fitted vehicle. It will be advantageous if it in advance has been established and levelled a plurality of anchoring towers 36 (see Figs. 13 and 14) for the base elements 6, 7 and where the base elements 6, 7 successively can be landed, oriented and fixedly welded into their individual positions.

Figs. 26 and 27 indicate a transport solution for tunnel arch forming elements 3, 4, 5 from open air and in towards the location for installation. The crane track 68 is electrified and modular, and is - as mentioned- equipped with at least one travelling carriage 69, where the crane rail 68 successively is installed via stays 67, 67' from threaded casings 30, 30' cast into the arch elements 5 at suitable distance from the edges thereof in order that the interspace cast 14 (see Fig. 27) also can contribute to stabilization of the tunnel lining 1 and the fitting of the crane track. One or more travelling carriages 69 having a winch 83 can be remotely controlled and quickly bring a larger number of elements 3, 4, 5 in towards wanted location for installation and such that the elements therefrom can be collected by means of the installation machinery 52. In practise, it is advantageous to transport elements 3, 4, 5 into the tunnel when there is little traffic and store the elements 3, 4, 5 in a standing position along the tunnel lining 1, e.g. during a period for drilling in preparation for a new blasting operation. It is however obvious that transportation of elements 3, 4, 5 in the indicated manner always can take place within a region of the cross-section of the tunnel which is not obstructed by other installations, except for other transport activity, viz. the region in the middle of the cross-section of the tunnel. Other advantages of a crane track 68 is that it also can be used for other kinds of transport and that it is directly re-usable. The attachment devices 30, 30' for the crane track 68 - 68" can later be used for other permanent installations in the tunnel, e.g. armatures for lighting. The travelling carriages 69 with winch 83 may be operated by radio control, be provided with warning light/ signal and automatic stop at obstructions located at regions of work. On Fig. 26 there is also indicated some temporary installations like ventilation pipes and suspension means for cables and pipes. As it it most likely that a tunnel lining 1 successively will be established close to tunnel face, it is most likely that the forwarding of said temporary installation mainly follows just behind the progress of the tunnel lining 1, but in such a way that hoses and cables over a period will lie on the tunnel bottom from the established tunnel lining 1 and onwards to tunnel face. However, it will be appreciated that required temporary means for delivery of electric power, water, pressurized air and ventilation will not present special problems with regard to the transport and installation of elements 3, 4, 5, 6, 7. Said temporary means may successively also be able to be moved from the tunnel bottom and be hung onto the tunnel lining 1 in order that the tunnel bottom will be completely free of obstructions when e.g. the tunnel foundation 25, 28 is to be cast.

The aspects of the invention can be taken further to relate to future use of arch elements 74, 74' having a sandwich structure as indicated on Figs. 28 and 29. Such sandwich structure type arch elements may be considered as an alternative to using elements 3, 4, 5; 3', 4', 5' of concrete. The elements 74, 74' can be provided by joining firesproof profiles 70, 71, 72; 70', 71', 72' into shells 73, 73', which can subsequently be filled with a fireproof, foamlike and relatively lightweight material. The profiles will suitably be made from metal or composite material or other materials which have fire resistant properties and simultaneously are resistant againt corrosion, decomposition, rust or other kinds of degradation of material properties.

Further, the concepts of the horizontal and vertical profiles of the arch elements of concrete, the base element, the flexible formworks, the inner formworks, ways of sealing, making interspace casts and foundations, smoothing cast, transporting and placing structural elements into position, and other aspects shown and described with respect to tunnel arch forming elements of concrete are equally or substantially applicable to tunnel arch forming elements of a sandwich structure.

A detailed description of these concepts and aspects of the invention is considered superfluous, as the description linked to the use of tunnel arch forming elements of concrete is fully instructive to the expert in the art if it is decided to use tunnel arch forming elements of sandwich structure.

Further, in some cases it is conceivable to use tunnel arch forming elements of concrete as well as tunnel arch forming elements of sandwich structure, suitably having corresponding dimensions or at least matchable dimensions. Thus, it could be visualized for a tunnel lining 1 of mainly tunnel arch forming elements of concrete to use for a few sections thereof tunnel arch forming elements of sandwich structure, or e.g. use a sandwich type arch element as top arch element (locking element) instead of a top element (locking element) of concrete. Alternatively, it could also be visualized to use arch elements of sandwich structure for the entire tunnel lining or a substantial part thereof. As regards the sandwich structured embodiment, an outer, flexible formwork 2 is established and the cavity 13 is closed by means of a section based lid 76 of a construction

corresponding to the elements, located in lid receiving recesses 75, 75' in the elements 74, 74' by means of a locking function. The lid 76 can at the linear edge have tongue and groove for mutual stabilization, and due to the low weight of the elements 74, 74', it is unproblematic to move adjacent elements 74' sideways, so that intended connection and engagement can be achieved. The interspace cast 14 can thereafter be created and the method is completed with a complete interspace cast 19 between rock 10 and arch elements 74, 74'. Injection paths 16 in all joints can in a favourable way be established and the arch elements 74, 74' will obviously and inherently be completely watertight.

Claims

C l a i m s

1. A method for constructing tunnel courses which are completely or partly surrounded by rock formations and/or are located in open air, the tunnel course in its longitudinal direction consisting of a plurality of mutually separate, pre-fabricated tunnel arch forming structural elements which are intended to be sealed against each other, comprising: a) installing along a tunnel course at each longitudinal side thereof tunnel element bases and cast these onto masses adjacent the bases,

-| b) placing from recesses on the bases successively in the longitudinal direction of the tunnel course with mutual distance self-supportive sections each consisting of at least two of said tunnel arch forming elements, wherein the tunnel arch forming elements are made of concrete or sandwich structure, c) arranging at the outside of the sections at the opening therebetween an outer, flexible formwork, d) arranging formwork equpiment across the opening between the sections at the inside of the sections, e) injecting concrete through the formwork equipment into a space defined by adjacent tunnel arch forming element sections, said outer flexible formwork and said formwork equipment, so that injected concrete expands the outer, flexible formwork outwardly and laterally at the outside of the tunnel course, and f) letting the injected concrete harden.

2. The method according to claim 1, the tunnel course being surrounded by rock masses, wherein feature a) further includes providing the base with a skirt attached thereto along a face of the base facing the inside of the tunnel course, the skirt being configured to form a flexible formwork, and fixedly casting the base into place by filling concrete into a space bordered by the base, neighbouring rock masses and the skirt.

3. The method according to claim 1, wherein said tunnel arch forming elements are made of concrete and provided on their outside with a watertight membrane.

4. The method according to claim 1 or 2, wherein the outer flexible formwork is provided by using two longitudinal skirts at the upright edges of adjacent tunnel arch forming element, and interconnecting the neighbouring skirts to form the flexible formwork.

5. The method according to claim 1 or 4, wherein each skirt is configured as a net, wherein concrete is injected into said space of which the flexible formwork forms a part until filled by concrete, and wherein some concrete is allowed to penetrate the flexible formwork provided by the interconnected net configured skirts.

6. The method according to claim 4 or 5, the tunnel course being surrounded by rock masses, further comprising letting the injected concrete press the flexible formwork to expand in order to contact a portion of adjacent rock mass.

7. The method according to claim 1, comprising after the hardening of concrete in feature f) injecting via pre-arranged injection path in upright contact faces on the tunnel arch forming elements sealing mass between the injected, hardened concrete and the adjacent tunnel sections.

8. The method according to claim 1 or 7, comprising injecting, via pre-arranged injection path at contact faces on the tunnel arch forming elements in direction of the tunnel course, sealing mass between adjacent elements of a tunnel section.

9. The method according to claim 1, wherein a compressible, open-pore mat is located between contact faces of the tunnel arch forming elements in the direction of the tunnel course, and wherein sealing mass is injected via the mat into the space between the contact faces.

10. The method according to claim 1, further providing a puncturable mat or cushion structure containing sealing mass between opposite edge faces of the tunnel elements located in the direction of the tunnel course, and upon joining the elements to form a tunnel section thereby puncturing the mat or cushion structure to form a sealing between the opposite contact faces.

11. The method according to claim 1 or 10, wherein in a recess of the bases there is located a puncturable mat or cushion structure containing sealing mass to interact with lowermost elements of a tunnel section, and causing the mat or cushion structure to be punctured when the lowermost elements enter the respective recess.

12. The method according to claim 1, comprising prior to step b) locating in recesses in the bases a fluid spreading mat, and injecting therein a sealing mass to spread the sealing mass in a space between the recesses and lowermost elements of a tunnel section entered into the recesses.

13. The method according to any one of the preceding claim, the tunnel course being surrounded by rock masses, further comprising injecting into cavities between the tunnel sections and the rock masses filler means in the form of concrete or loose filler material.

14. The method according to any one of claims 1 - 12, the tunnel course being located in open air, further comprising applying concrete or other covering means to the outside of tunnel sections formed by tunnel arch forming elements.

15. The method according to any one of claims 1 - 14, wherein, following feature f), the tunnel course is completed by casting a tunnel foundation after a membrane is established on a smoothing cast on a bed formed by rock or filler material.

16. A structural element for use in manufacturing a tunnel course according to the method of any one of claims 1 - 15, wherein the element is of concrete or a sandwich structure, and wherein the element on the outside thereof at either edge to be positioned upright and extending in a direction transversely of the longitudinal direction of the tunnel and the element, is provided with a first, outer, flexible formwork half which is configured to be interconnectable with a corresponding second, outer, flexibel formwork half on a

neighbouring further structural element when said further structural element is positioned next to the first mentioned element, to form a flexible formwork for receiving concrete injected between the adjacent elements and into the flexible formwork.

17. The structual element according to claim 16, wherein the structural element is made of concrete, and wherein its outside face is provided with a watertight membrane.

18. The structural element according to claim 16 or 17, wherein said outer, flexible formwork halves each consists of attached skirt configured as a net, injectable concrete being locatable in a space defined by the interconnected, flexible formwork halves and opposite upright side edges of adjacent tunnel arch forming structural elements.

19. The structural element according to claim 18, wherein the net has a mesh width which is small enough to prevent the largest sized added material of the injected concrete to pentrate the net configured flexible formwork, and large enough to allow smaller sized parts of the added material over at least a part of the injection period to penetrate the flexible formwork.

20. The structural element according to any one of claims 16 - 19, configured for a tunnel lining surrounded by rock masses, wherein the flexible formwork has a property of flexibility which allows injected concrete to press the flexible formwork to come to rest against a portion of the rock mass.

21. The structural element according to any one of the claims 16 - 20, comprising an injection path moulded- in or arranged in the contact faces of the structural element which extend transversly of the tunnel course, the injection path capable of causing sealing mass to be injected into a space between injected, hardened concrete forming an interspace cast and tunnel arch forming elements adjacent thereto.

22. The structural element according to any one of claims 16 - 21, wherein an injection path, located in at least one of the contact faces of the structural element which extends in the direction of the tunnel course, is provided to allow injection of sealing mass between contact faces of adjacent elements which extend in such a direction.

23. The structural element according to any one of claims 16 - 21, wherein in a space between contact faces of elements extending in the direction of the tunnel course, there is arrangable a compressible, open-pore mat capable of receiving sealing mass to seal said space.

24. The structural element according to any one of claims 16 - 21, wherein sealing in a space between contact faces of elements extending in the direction of the tunnel course is provided by a puncturable mat or cushion structure which contains a sealing mass and to be located in said space.

25. The structural element according to any one of claims 16 - 21, further comprising a puncturable mat and cushion structure containing sealing mass to provide sealing between lowermost elements of the tunnel arch forming elements and corresponding base elements below shaped to receive a lowermost end of said lowermost elements.