WO2001083949A2

WO2001083949A2 - Tunnel building device

Info

Publication number: WO2001083949A2
Application number: PCT/NL2001/000340
Authority: WO
Inventors: Maarten Willibrord Petrus Van Lange; Richard Johannes De Braak; Hans Arnold Greve
Original assignee: I.T.M. Industriële Tunnelbouw Methode C.V.
Priority date: 2000-05-03
Filing date: 2001-05-03
Publication date: 2001-11-08
Also published as: WO2001083949A3; EP1278941A2; NL1015097C2; AU2001255108A1

Abstract

A device for producing an underground tunnel comprises an excavating device which can be moved through the ground, in order to form an elongated hole in the ground. Formwork placed in the hole behind the excavating device bounds a formwork space between the formwork and the wall of the hole, and supports a lining material in the formwork space. Provision is also made for lining material supply means, for supplying the lining material to the formwork space. A controllable valve forms part of the lining material supply means, and comprises a valve housing with three housing apertures, a rotatable valve body being capable of forming a connection between two of the three valve bodies for supplying lining material, on the one hand, and cleaning supply pipes, on the other hand. A lining material pump is filled under pressure with lining material.

Description

Tunnel building device

The invention relates to a tunnel building device.

EP-A-0 897 050 discloses a method for building a tunnel provided with a substantially annular lining, using removable formwork elements. The lining, made of a hardening material, such as concrete, particularly fibre-reinforced concrete, and more particularly steel-fibre-reinforced concrete, is divided in its longitudinal direction into tunnel sections prior to the hardening of the lining material. For the formation of a tunnel section, the lining material is taken into a space substantially bounded by the formwork elements and the ground, by pumping the lining material from a tank by means of a pump by way of a pipe through a seal into the space. Only one injection point for the lining material is indicated. However, for the purpose of obtaining the most uniform distribution of lining material in the circumference of the formwork elements that is possible, it is better, and is also usual, to fill the space round the circumference by way of several injection points. Examples of such a method are described in US-A-4 768 898 and EP-A-0 336 331. According to these publications, lining material is supplied successively to the different injection points from one central pump by way of a system of pipes in which valves or the like are accommodated.

In particular, EP-A-0 336 331 describes a pump system which is connected to an annular conduit, from which lining material can be supplied to different parts of the space to be filled by way of branch pipes provided with valves.

A disadvantage of the system according to EP-A-0 336 331 is that the delivery pressure is different in each of the different branch pipes and cannot be set independently of that in the other branch pipes . Another disadvantage is the use of a single pump, which makes the system susceptible to failure of the pump.

A further disadvantage is that the lining material flowing through the annular conduit passes through all valves, which makes it impossible to isolate one of the valves, for example for repair, maintenance or cleaning.

Another disadvantage is that, as a result of the specific shape of the valves, the shut-off elements of said valves must be pressed into the lining material in order to stop the flow of lining material at that point.

Yet another disadvantage of the known system is its unsuitability for the use of a liquid, such as water, for cleaning the system if fibre-reinforced concrete is used as the lining material in it. If for cleaning purposes, use is made of a pig or the like which is forced through the pipe system and leakage occurs along the pig, then the concrete segregates; the fine sand and cement parts wash out and any fibres present form lumps with the gravel, with the result that serious blockages occur.

According to EP-A-0 897 050, the lengths of the tunnel sections are selected in such a way that the individual sections can shrink during the hardening process, and subsidence of the surrounding ground can follow. Gaps between adjoining tunnel sections are filled with a sealant.

There are problems with the removal of the formwork elements after the tunnel lining hardens because shrinkage of the lining material occurs not only in the axial direction of the tunnel sections, but also in their radial inward direction. As a result of this, the sections, depending on the shrinkage which occurs, ultimately become stuck to a greater or lesser degree around the formwork elements, which makes removal of the formwork elements difficult.

The object of the invention is first to provide a tunnel building device and method, for providing lining material easily, uniformly and reliably between formwork elements and the surrounding ground.

Another object of the invention is to provide means for simple and efficient cleaning of the tunnel building device. In order to achieve these and other objects, the invention provides lining material supply means which comprise a controllable valve with: a valve housing provided with a first housing aperture for supplying the lining material, a second housing aperture for discharging lining material, and a third housing aperture for supplying cleaning agents; and a valve body which is movable in the valve housing and is provided with a through channel having a first channel aperture and a second channel aperture, which first channel aperture, by moving the valve body, can be brought into line with one of the first, second and third housing apertures as desired, the second channel aperture being brought into line with the third, first and second housing apertures respectively, while the other housing apertures are always shut off by the valve body. In the valve according to the invention two of the three housing apertures can always be interconnected hydraulically by means of a single channel in the valve body, for the purpose of allowing through the lining material or cleaning (the channel in the valve body of) the valve . For a simple, cheap and efficient construction, the valve body is rotatable in the valve housing, and in particular the valve body and the side of the valve housing facing the valve body are substantially cylindrical . The first and second channel apertures are preferably situated on the cylindrical side of the valve body.

It should be pointed out that the valve can be used not only in the device according to the invention, but also independently.

The invention further provides lining material supply means with a pump, which comprises: a pump housing having a pump housing chamber which can be put under pressure, a pump housing supply inlet for supplying the lining material, and a pump housing discharge outlet for discharging the lining material, the pump housing chamber being in open hydraulic communication with the pump housing supply inlet; at least two delivery chambers, each with a single-acting piston movable therein, for varying the volume of the delivery chamber, each delivery chamber being in hydraulic communication, by way of a delivery chamber aperture, with the pump housing chamber; and a pump body which is movable in the pump housing and is provided with a through channel having a first channel aperture and a second channel aperture, which first channel aperture, by movement of the pump body, can be brought into line with one of the delivery chamber apertures as desired, and in which the second channel aperture is constantly in open hydraulic communication with the pump housing discharge outlet. Supplying lining material to the pump housing chamber under pressure ensures good filling of the pump. This also ensures that during the movement of the pump body in the pump housing chamber lining material does not flow back out of the pump housing discharge outlet and the pump body channel into the pump housing chamber. Furthermore, the pistons can be single-acting pistons, since the delivery chambers, as a result of the pressure prevailing therein, will fill by themselves from the pump housing chamber, thus moving the pistons, when on bringing the first channel aperture into line with any delivery chamber aperture, at least one of the other delivery chamber apertures is always in open hydraulic communication with the pump housing chamber. For ensuring good cleanability of the pump, the first channel aperture can additionally be brought into hydraulic communication with the pump housing supply inlet by moving the pump body, and in particular the pump housing is provided with an aperture which gives access to the pump housing chamber, which aperture is released by the pump body when the first channel aperture of the pump body is in line with the pump housing supply inlet.

For a simple, cheap and efficient construction, the pump housing is internally of a substantially cylindrical shape, the pump body being shaped like a cylinder segment and being rotatable through a predetermined angle in the pump housing. The cylinder diameter and the cylinder length of the pump body preferably correspond substantially to the inside diameter and the inside length of the pump housing respectively, with the result that the pump body can perform a sealing action inside the pump housing chamber.

In further preferred embodiments the lining material supply inlet and the lining material discharge outlet are provided at opposite ends of the pump housing, and the delivery chamber apertures are provided on one of the ends of the pump housing.

It should be pointed out that the pump can be used not only in the device according to the invention, but can also be employed independently. The invention further provides formwork, composed of formwork rings which each comprise a number of formwork segments, a wedge-shaped tensioning element which tapers off in the radially outward direction being fitted between two adjoining formwork segments, which tensioning element can be moved inwards and outwards substantially in the radial direction by means of an adjusting device. The number of tensioning elements lies between 1 and n, where n represents the number of formwork segments . The adjustment of the tensioning element or, if the formwork ring has more than one tensioning element, the adjustment of one or more of the tensioning elements, has the result that the circumference of the formwork ring formed by the formwork segments can be varied within certain limits. In this way the formwork ring can be adjusted to its largest circumference at the commencement of placing the lining around it, and the circumference of the formwork ring can be reduced continuously or in steps during the hardening and shrinking of the lining by means of the adjusting device for reducing the load exerted on the formwork rings as a result of the shrinkage.

Finally, at the end of the hardening process of the lining material, the circumference of the formwork ring can be reduced in such a way that the formwork ring comes away from the lining.

In a preferred embodiment, the excavating device comprises a head shield and a tail shield situated behind it, which shields are interconnected round the circumference thereof by means of piston/cylinder units. The assembly of the piston/cylinder units acts like a ball joint between the head shield and the tail shield, with the result that the excavating device can easily follow curved routes through the ground. This design also has the advantage that lining material can still be supplied for some time to a formwork space situated behind the tail shield, even when the head shield is at a standstill, by retracting the piston/cylinder units. In a further preferred embodiment, the head shield is connected to the formwork by means of a number of double-acting piston/cylinder units disposed round the circumference of said head shield, and provision is made for head shield control means which are designed for individually controlling the force produced by each of the piston/cylinder units for propelling the head shield through the ground. In particular, the head shield control means are designed for setting a pressure point of the total propulsion force supplied by the piston/cylinder units for following a route in the ground. When one or more piston/cylinder units is/are retracted in order to make room for placing a further formwork segment of a formwork ring, the head shield control means are preferably designed to retain the pressure point, so that the head shield can remain continuously in operation, despite an adjustment of the formwork.

In a preferred embodiment, the excavating device is provided with an injection ring forming a boundary of the formwork space and having a number of injection apertures placed around its circumference, which injection apertures are in communication with the lining material supply means. In particular, a flexible sealing ring extending in the formwork space and provided with an interior space is connected to the injection ring, the external dimensions of the sealing ring being adjustable by supplying a fluid to or removing it from the interior space. In this way it can be ensured that no groundwater and/or soil flows into the formwork space, in particular during the start-up of the supply of lining material to the formwork space.

Each injection aperture is advantageously connected to a pump,- provision being made for pump control means, for controlling the flow rate and the delivery pressure of the respective pumps . Such an arrangement makes it possible to inject more or less lining material at certain points round the circumference of the injection ring than at other points, in order to take account of, for example, pressure differences round the circumference or volume differences round the circumference on account of a curved route being taken.

In a preferred embodiment, the pump control means are designed to measure the speed of propulsion of the excavating device, and on the basis of said speed to adjust the flow rate from each pump. In a further preferred embodiment, the pump control means are designed to measure the ground pressure in the vicinity of each injection aperture, and on the basis of said pressure to adjust the delivery pressure of each pump in accordance with the ground pressure measured at the appropriate injection aperture.

The invention is explained further with reference to the appended drawing, in which non-limiting exemplary embodiments are shown.

Fig. 1 shows a perspective view of two contiguous formwork segments of a formwork element.

Fig. 2 shows on an enlarged scale a side view of the formwork segments according to Fig. 1. Fig. 3a shows diagrammatically a side view, partially in section, of an assembly of formwork segments and a tensioning element, the formwork segments being shown in the developed state.

Fig. 3b shows a section through a part of the adjusting device of the tensioning element according to Fig. 3a along the line Illb-IIIb.

Fig. 4 shows an assembly of formwork rings composed of an assembly of formwork segments.

Fig. 5a shows a valve in front view. Fig. 5b shows the valve according to Fig. 5a in a side view according to arrow Vb in Fig. 5a.

Fig. 6 shows a perspective view of a pump for lining material .

Figs. 7a, 7b and 7c show the pump according to Fig. 6 in side, top and front views respectively.

Fig. 8 shows a diagram to illustrate the functioning of the system according to the invention during the supply of lining material to a formwork space.

Fig. 8a shows a part of the diagram of Fig. 8 with a modified arrangement of the relevant components.

Fig. 9 shows a diagram to illustrate the functioning of the system according to the invention during flushing of the pipes and components when the supply of lining material to a formwork space has been stopped. Fig. 10 shows a subsequent phase of the operating state of the system discussed with reference to Fig. 9.

Fig. 11 shows a longitudinal section through a part of the formwork space and the seal interacting with it. Figs. 12a and 12b show in a side view, partially in longitudinal section, contiguous parts of a system according to the invention in a hole in the ground.

Fig. 13 shows a cross section through the system according to Fig. 12a according to arrows XIII in Fig. 12a.

In the various figures the same reference symbols are used for the same parts or parts with the same function. Arrows without reference numerals are used to indicate the direction of flow of material or for the direction of movement of components . For a good understanding of the functioning of the system according to the invention, a number of its components will first be discussed below in detail as regards construction and functioning. How it functions in principle will then be explained. Finally, a number of embodiments of component assemblies and their functioning and application will be described.

Figs. 1 and 2 show formwork segments 2 and 4, which formwork segments are each composed of a number of interconnected, possibly profiled construction parts. On the sides where the formwork segments 2, 4 adjoin each other in the tangential direction, they are provided respectively with an axial rib 6 and a groove 8 of a complementary shape, for fixing the formwork segments 2, 4 together in the radial direction. On one of the sides where the formwork segments 2, 4 are intended to^' adjoin other formwork segments in the axial direction, provision is made for a lug (not shown in the figures) which can engage in a hole 3 of an adjoining formwork segment.

Figs. 3a and 3b show formwork segments 10, 12 in the developed state, in which a substantially wedge-shaped tensioning element 14 is placed between the sides where the formwork segments 10, 12 adjoin each other. The tensioning element 14 is moved by an adjusting device, and to that end is provided with a lug 16 in which a hole 18 provided with screw thread is arranged. A pin 22 provided with screw thread 20 is screwed into the hole 18, which pin is freely rotatable in a bearing 24 in the formwork segment 12. By rotation of the pin 22 in one of the directions of double arrow 26, the tensioning element 14 is moved as desired in one of the directions of double arrow 28, with the result that the distance between the formwork segments 10, 12 varies accordingly. The external circumference (at the top of the figure in Fig. 3a) of the formwork ring formed by the formwork segments 10, 12 and additional formwork segments varies in this way. During the positioning of a formwork ring for the purpose of forming a tunnel wall lining, the tensioning element 14 is moved into the position shown in Fig. 3a. The lining is then positioned and allowed to harden, during which process shrinkage occurs, particularly in the axial direction. Sealing sections are fitted between formwork rings, in order to prevent leakage of lining material. During and/or after the hardening of the lining material, the tensioning element 14 is moved in such a way that the distance between the formwork segments 10, 12 decreases, with the result that mechanical stresses in the formwork ring are reduced or eliminated, and the formwork ring can easily be loosened.

Fig. 3a shows the tensioning element 14 as being tapering in the radial direction towards the outer circumference of the formwork. The effect of a variation of the outer circumference of a formwork ring which is obtained when the tensioning elements 14 are used can, however, also be obtained by using a tensioning element which tapers in the radial direction towards the inner circumference of the formwork ring.

Fig. 4 shows a number of (in this case sixteen) formwork rings 30 composed of formwork segments. Round the circumference of each formwork ring 30 at least one tensioning element 14 is provided between two adjoining formwork segments, for the purpose of varying the circumference of the formwork ring.

Figs. 5a and 5b show a valve, which is indicated in its entirety by reference numeral 40. The valve 40 comprises a valve housing 41, which is composed of a cylinder 42 and two flanges 44, each of which is fixed with six bolts to the cylinder 42. The cylinder 42 is provided with a first housing aperture 46, a second housing aperture 48 and a third housing aperture 50, each displaced through an angle of 120 degrees relative to each other, and also comprises two fixing flanges 52, for fixing the valve 40 to another component. Pipe branches 54 and 56 are connected to the first and the second housing apertures 46, 48 respectively. A cylindrical valve body 58 is disposed rotatably in the valve housing 41. The valve body 58 is connected to, and can be rotated with the aid of, an external double arm 60 by way of a passage (not shown in any further detail) in one of the flanges 44. The valve body 58 is provided with a channel 62 which has channel apertures 64 and 66. In the position of the valve body 58 shown in Fig. 5a the channel aperture 64 is in line with the housing aperture 46, and the channel aperture 66 is in line with the housing aperture 48, with the result that the channel 62 connects the housing apertures 46 and 48 to each other and the valve body 58 shuts off the housing aperture 50. It will be clear that by rotation of the valve body 58 the channel aperture 64 can also be brought into line with the housing aperture 48, in which case the channel aperture 66 is in line with the housing aperture 50, so that the channel 62 connects the housing apertures 48 and 50 to each other and the valve body 58 shuts off the housing aperture 46. It will furthermore be clear that by rotation of the valve body 58 the channel aperture 64 can also be brought into line with the housing aperture 50, in which case the channel aperture 66 is in line with the housing aperture 46, so that the channel 62 connects the housing apertures 46 and 50 to each other and the valve body 58 shuts off the housing aperture 48. In particular, the housing aperture 50 is connected to a formwork space, one of the housing apertures 46, 48 is connected to a supply conduit for supplying lining material to the formwork space when the valve 40 is in a suitable position, and the remaining housing apertures 46, 48 are connected to an infeed conduit for feeding a pig into the abovementioned supply conduit when the valve 40 is in a suitable position, as will be described in greater detail below with reference to Figs. 8, 8a, 9 and 10.

Figs. 6, 7a, 7b and 7c show a pump, which is indicated in its entirety by reference numeral 70. The pump 70 comprises a substantially cylindrical pump housing 72, which comprises a cylindrical casing 74 and end flanges 76 and 78.

The end flange 76 of the pump housing 72 is provided with three circular apertures, the centre points of which are situated at the same distance from an imaginary central axis of the pump housing 72. A branch connection 80 for a supply conduit for lining material is placed on a first of the three apertures, and piston/cylinder units 82, 84 are placed on the other two of the apertures, the cylinders of the piston/cylinder units 82, 84, by way of the apertures in question, being in open hydraulic communication with the interior of the pump housing 72. Pistons 82a and 84a of the piston/cylinder units 82, 84 respectively are in turn connected to single-acting piston/cylinder units 86 and 88 respectively. Piston rods 86a and 88a respectively are guided through a chamber 90 for purposes of inspection, cleaning, maintenance and repair.

The end flange 78 is provided with a central aperture, to which a branch connection 92 for a discharge conduit for lining material is connected.

A pump body 94 is disposed in the pump housing 72 in such a way that it is rotatable relative to the imaginary central axis of the pump housing 72. The pump body 94 is provided with a curved through channel 96, which in three different angular positions of the pump body 94 can bring about a hydraulic communication between the branch connection 92, on the one hand, and the branch connection 80, the piston/cylinder unit 82 or the piston/cylinder unit 84, on the other hand. The pump body 94 is connected to an arm 106, which can swivel through an angle which corresponds to the angle between the apertures of the pump housing 72 on which the piston/cylinder units 82, 84 have been placed. In order to bring about this swivelling movement, provision is made for piston/cylinder units 101 and 103, which can make the arm 106 swivel relative to a yoke 108. By means of piston/cylinder units 101 and 103, the pump body 94 is moved between two positions in which the channel 96 forms a through connection between the branch connection 92, on the one hand, and the piston/cylinder unit 82 or the piston/cylinder unit 84, on the other hand. The pump body 94 is preferably designed in such a way that it completely releases one of the apertures of the piston/cylinder units 82, 84 only when the channel 96 is in line with the other aperture of the piston/cylinder units 82, 84, and shuts off the apertures of the piston/cylinder units 82, 84 during the transition from the one to the other aperture. The yoke 108 is connected to an external gear ring 98, with which a gearwheel 102 which can be driven by a motor 100 meshes, in order to rotate the yoke 108, and thus the pump body 94, through 180° out of the position shown in Figs. 6, 7a, 7b and 7c, so that the channel 96 forms a through connection between the branch connection 80 and the branch connection 92. The pump housing 72 is provided on its underside with a cover 104, which covers an aperture in the pump housing, through which aperture access can be gained to the interior of the pump housing 72. The cover 104 can also be provided in the interior of the pump housing 72 and can be connected to the pump body 94, in which case the cover 104 is shaped in such a way that it releases the corresponding aperture in the pump housing 72 only when the pump body 94 brings about a hydraulic communication between the branch connections 80 and 92, and blocks the aperture in the remaining positions . For the pumping action of the pump 70, lining material is supplied under pressure, by way of the branch connection 80, to the pump housing 72. In the position of the pistons 82a, 84a shown in Figs. 7a and 7b, part of the pump housing 72 and the cylinder of the piston/cylinder unit 84 will fill with lining material. By not energizing both piston/cylinder units 86, 88, the piston 82a of the piston/cylinder unit 82 in the figure will be driven to the right by the pressure of the lining material supplied to the pump 70, and the cylinder of the piston/cylinder unit 82 will also fill with lining material. The pump body 94 is then rotated by means of the piston/cylinder units 101, 103 in such a way that the channel 96 forms a hydraulic communication between one of the piston/cylinder units 82, 84 and the branch connection 92. Subsequently energizing the piston/cylinder unit 86 or 88 in question causes lining material to be pushed out of the cylinder of the piston/cylinder unit 82 or 84 and into the channel 96 and, if the latter is already completely full, into the branch connection 92. Processing the lining material in this way constantly under pressure ensures that it does not segregate. In the meantime, the other piston/cylinder unit 82, 84 fills with lining material supplied under pressure to the pump housing 72 by way of branch connection 80, after which the pump body 94 is rotated to the relevant other piston/cylinder unit 82, 84, from which the lining material present in it can be expelled into the channel 96 of the pump body 94. Owing to the fact that the lining material is supplied under pressure to the pump housing 72, during the rotation of the pump body 94 no lining material can flow back out of the branch connection 92 into the pump housing 72. No "short-circuiting" of flow of lining material occurs between the piston/cylinder units 82 and 84, since the apertures of the piston/cylinder units 82, 84 are placed at such a distance from each other that the channel 96 does not form a through connection between the apertures in any position of the pump body 94 at all. In this way the pump 70, by way of the branch connection 92, can deliver a semi-continuous stream of lining material which can be metered very well as regards volume and pressure by varying the stroke and the pressure of the respective piston/cylinder units 86, 88, which means that the thickness of the tunnel wall to be built with the lining material can be regulated very well and subsidence of the surrounding ground can be prevented.

For the purpose of cleaning/flushing the pump 70 and the pipes connected to it, the pump body 94 is placed by means of the drive 98, 100, 102 in such an angular position that the channel 96 produces a hydraulic communication between the branch connection 80 and the branch connection 92. A pig can then be forced out of a pipe connected to the branch connection 92, by way of the branch connection 92 and the channel 96, to the branch connection 80 and the pipe connected to it, or in the opposite direction. At the same time, the pistons 82a, 84a can be moved into a position such as that shown for piston 82a in Figs. 7a and 7b, for emptying the appropriate cylinders, and spray devices (not shown in any further detail) installed in the pump housing 72 are put into operation. The cover 104 is opened here, so that the residues of lining material still present in the pump housing 72 can leave the pump housing through the effect of gravity.

Fig. 8 shows a part of a lining material injection system with a number of (in the present case eight) pumps 70a, 70b, 70c, ..., only three of which are shown in the figure. The various pumps are each connected by way of pipes 110a, 110b, 110c, ... to one of the apertures 46, 48 of valves 40a, 40b, 40c, ... of the type described with reference to Figs. 5a and 5b. Apertures 50 of the valves 40a, 40b, 40c, ... are connected to various apertures in a seal 114 which bounds a part of the formwork space. The valves 40a, 40b, 40c, ... are connected by way of the other aperture 46, 48 to pipes 116a, 116b, 116c, by way of which a pig can be transported to the valves 40a, 40b, 40c, ... . The pumps 70a, 70b, 70c, ... are connected by way of pipes 118a, 118b, 118c, ... to a pressure vessel 120, to which lining material can be supplied, by way of a pipe 122, by a transmission pump 124. The pressure vessel 120 comprises a revolver distribution piece 126, which for the sake of clarity is illustrated next to the pressure vessel 120, and the use and functioning of which will be explained below. The lining material injection system also comprises a waste pipe 128, waste collection tanks 130, a mixer 132 and a lining material waste wagon 134. In operation for filling a formwork space with lining material, the lining material injection system functions as follows. The lining material is mixed in the mixer 132 and then, as Fig. 8a illustrates, unloaded into a tank of the transmission pump 124. The transmission pump 124 pumps the lining material by way of the pipe 122 to the pressure vessel 120, from which the lining material is supplied under pressure by way of the pipes 118a, 118b, 118c, ... to the pumps 70a, 70b, 70c, ..., which in turn supply the lining material by way of the pipes 110a, 110b, 110c, ... and the valves 40a, 40b, 40c, ... at various injection points to the formwork space situated behind the seal 114. Since a separate pump is provided for each injection point, the pressure and the flow rate of the lining material can be controlled for each injection point. This also means that, if one of the components providing the supply of lining material to a specific injection point fails, with the result that no supply of lining material occurs to that specific injection point, it becomes possible to adjust accordingly the supply of lining material to the remaining injection points which are in use.

In operation for the filling of a formwork space after a stop in the filling process, a starting mixture is processed in the lining material injection system in the first instance. The starting mixture is a thin, readily pumpable mortar with a high end strength. The starting mixture has a dual purpose. First, it ensures that a thin layer is applied to the walls of the clean and empty pipe system, so that lining material can subsequently be pumped successfully through said system. Secondly, the starting mixture can be pumped into a restricted advance aperture (= the space between the seal 114 and the hardened lining material in the formwork space) , thanks to a low maximum granule size corresponding to that of the coarse sand fraction in the mortar. After pumping and injecting the starting mixture over a distance of a few cm into the formwork space, the final lining material, such as (steel-) fibre-reinforced concrete, is also pumped. At that time the concrete no longer encounters resistance from an initial narrow advance aperture, with the result that the risk of dehydration and a blockage of the injection process is eliminated. The starting mixture is prepared in a separate mortar-preparation plant and pumped by means of the transmission pump 124 to the pressure vessel 120. The transition from the starting mixture to the final lining material is gradual, since the lining material is poured into the same pressure vessel 120 using the same transmission pump 124. In operation for the removal of lining material from the lining material injection system, for example in the case of a planned stop or an emergency stop, the tank of the transmission pump 124 is emptied by way of a line 136 into the lining material waste wagon 134. The transmission pump 124 is also brought into such an operating state that a through connection between the pipes 122 and 136 is produced. Vents of the valves 40a, 40b, 40c, ... are opened, and pigs are conveyed by means of air pressure to the valves 40a, 40b, 40c, ... by way of the pipes 116a, 116b, 116c, .... The channel 62 of the valve bodies 58 of the valves 40a, 40b, 40c, ... is then in the position for conveying lining material out of the pipes 110a, 110b, 110c, .... to the formwork space, so that the pigs knock against the valve bodies 58. When this situation has been reached, the air vents of the valves 40a, 40b, 40c, ... are closed. As can be seen from Fig. 9, the revolver distribution piece 126 then produces a communication between one or more of the pipes 118a, 118b, 118c, ..., on the one hand, and the pipe 122, on the other hand. After the rotation of the valve body 58 of one or more of the valves 40a, 40b, 40c, ..., so that a through connection is produced between one or more of the pipes 116a, 116b, 116c, ... and the pipes 110a, 110b, 110c, ..., the pig(s) situated in front of the valve bodies 58 can be moved further, through the pipe system by means of air pressure, the pump body 94 of one or more of the pumps 70a, 70b, 70c, ... also being rotated in such a way that a through connection is produced between one or more of the pipes 110a, 110b, 110c, ... and the pipes 118a, 118b, 118c, .... During this process each pig pushes lining material ahead of it through one of the valves 40a, 40b, 40c, ..., one of the pipes 110a, 110b, 110c, ..., one of the pumps 70a, 70b, 70c, ..., one of the pipes 118a, 118b, 118c, ..., the revolver distribution piece 126, the pipe 122, the transmission pump 124 and the pipe 136. The part of the pipe system concerned is empty as soon as the pig lies in the lining material waste wagon 134. It is preferable for each valve 40a, 40b, 40c, ..., each corresponding pump 70a, 70b, 70c, ... and the corresponding pipes to be emptied separately, but it is also possible to empty several simultaneously, provided that measures are taken to ensure that the pigs do not interfere with each other in the revolver distribution piece 126 and the stretch situated downstream. It will be clear that in the event of a fault or blockage in one of the components handling the supply of lining material to a specific injection point, it is possible to take only the pipe system part concerned out of operation and repair or unblock it in the manner explained above.

Opening the housing 72 of the pumps allows the lining material situated in the housing of the pumps 70a, 70b, 70c to flow into one of the waste collection tanks 130. As Fig. 10 shows more particularly, the pressure vessel 120 is opened and cleaned above a waste collection tank 130. The waste pipe 128 can be cleaned if necessary. After the removal of the lining material from the system components has been completed, the pigs can be removed from the lining material waste wagon 134, and the mixer 132 can be cleaned. Fig. 11 shows a detail of the lining material injection system at the position of the seal 114 in the ground 148, which seal is shown only diagrammatically in Figs. 8-10. A number of valves 40, only one of which is shown, are accommodated in a substantially annular supporting structure 150, which is placed around a formwork ring 152, and is designed to move in the direction of arrow 153. The third housing aperture 50 of each valve 40 is directed towards an annular formwork space 154 which can be filled with lining material. The supporting structure 150 comprises a number of annular formwork sealing collars 156, three of them in the case illustrated. A fluid can be introduced under pressure by way of a pipe 160 into areas 158 bounded by the formwork sealing collars 156 and the formwork 152, for the purpose of improving the sealing action of the formwork sealing collars 156. The supporting structure 150 bears on the side of the formwork space 154 an annular seal 162 made of a flexible material and having a hollow space which can be filled with a fluid using means not shown in any further detail, for the purpose of protecting the advance aperture from the inflow of groundwater and/or soil before and during the introduction of the starting mixture into the formwork space 154.

Figs. 12a, 12b and 13 show the tunnel building device in greater detail. The device comprises a head shield 170 and a tail shield 172, which shields are interconnected by means of a number of - in the case illustrated twelve - piston/cylinder units 174 placed round the circumference of the shields 170, 172, which are indicated below as articulated cylinders. The cylinder 174a of the articulated cylinders 174 is connected to the head shield 170, while the piston rod 174b of the articulated cylinders 174 is connected to an annular profile 176 of the tail shield 172. Of a number of - in the case illustrated twenty-four - piston/cylinder units 178 fitted in the front shield 170 around its circumference, called main cylinders below, the cylinder 178a is connected to the front shield 170, while the piston rod 178b rests against the formwork rings 30. The main cylinders 178 are intended for propelling the front shield 170, which is provided with a drilling device 180, in the direction of the arrow 153, while the articulated cylinders 174 in principle pull along the tail shield 172 in a passive manner. The articulated cylinders 174 act as a ball joint here. Moreover, the articulated cylinders are also actively controllable for reasons which will be explained below.

Pipes 182 are provided in the tail shield 172, which pipes are connected in a manner not shown in any further detail to the pumps 70a, 70b, 70c, ... and serve to supply the starting mixture and the lining material to the formwork space 154. The pumps 70a, 70b, 70c, ... are fitted on a bearing structure 184 disposed centrally in the tail shield 172. A first manipulator 188 for transporting formwork segments in the longitudinal direction of the tunnel can be moved on the bearing structure 184 by means of a conveyor system 186. Such formwork segments can be taken over by a second manipulator 190 and placed in position, as illustrated in Fig. 12a in particular. Before that, the main cylinders 178 on the peripheral position of the formwork segment to be newly placed are, of course, retracted.

The tunnel building device, the components of which are described above, is designed as follows. A separately controllable pump is available for each injection point, while the maximum total pump capacity required for the production of the tunnel wall can also be supplied by the other pumps should a predetermined number of pumps not be available. Since the production of a tunnel wall with a prescribed minimum thickness is desired, a certain total quantity of lining material is injected, depending on the speed of the supporting structure 150 relative to the formwork 152. To this end, the pumps 70a, 70b, 70c, ... connected to the valves 50 are infinitely variable in flow rate. The pumps 70a, 70b, 70c, ... deliver a minimum flow rate at a certain speed in order to inject a suitable quantity of lining material per unit time. Where there are slight differences in flow rates between the different pumps, the lining material flows into the formwork space from the injection point with the higher flow rate to the injection point with the lower flow rate, so that no difference in filling level of the tunnel wall occurs. In addition to the flow rate regulation, the lining material is injected at a certain pressure, which pressure is directly related to the locally measured ground pressure. The ground pressure varies over the height of the tunnel, and the pressure of the lining material at the position of the injection points is therefore not the same for all injection points in the case of a uniform tunnel wall thickness.

The propulsion of the head shield 170 is pressure- controlled. A certain oil pressure is admitted to the main cylinders 178, and the resulting movement is controlled by means of a previously fixed route. If, on checking, a deviation from the route is established, then the pressure point of the total propulsion force supplied by the main cylinders 178 is shifted by controlling the pressure of the individual main cylinders 178, so that the tunnel building device starts to follow a different route. Such a check is carried out regularly. The formwork rings 30 can be of a conical design.

Prior to the retraction of two main cylinders 178 in order to place a new formwork segment, the total propulsion force is determined in each case, as is the position of the pressure point. During the retraction of the two main cylinders 178, the pressure over the other main cylinders 178 is distributed in such a way that both the total propulsion force and the position of the pressure point do not change. In this way it is possible to keep the drilling device 180 in operation while new formwork segments are being installed, with the result that a continuous drilling process is obtained.

When the drilling process is stopped, lining material can still continue to be placed in the formwork space 154 for some time by retracting the articulated cylinders 174. In this way it is possible to process already prepared lining material and to bridge a period of time up to the restarting of the drilling process without stopping the injection of lining material.

Claims

1. Device for building an underground tunnel, comprising: an excavating device which can be moved through the ground, in order to form an elongated hole in the ground; formwork placed in the hole behind the excavating device, for bounding a formwork space between the formwork and the wall of the hole, and for supporting a lining material in the formwork space; and lining material supply means for supplying the lining material to the formwork space.

2. Device according to claim 1, characterized in that the lining material supply means comprise a controllable valve with: a valve housing provided with a first housing aperture for supplying the lining material, a second housing aperture for discharging lining material, and a third housing aperture for supplying cleaning agents; and a valve body which is movable in the valve housing and is provided with a through channel having a first channel aperture and a second channel aperture, which first channel aperture, by moving the valve body, can be brought into line with one of the first, second and third housing apertures as desired, the second channel aperture being brought into line with the third, first and second housing apertures respectively, while the other housing apertures are always shut off by the valve body.

3. Device according to claim 2, characterized in that the valve body is rotatable in the valve housing.

4. Device according to claim 2 or 3, characterized in that the valve body and the side of the valve housing facing the valve body are substantially cylindrical.

5. Device according to claim 4, characterized in that the first and second channel apertures are situated on the cylindrical side of the valve body.

6. Device according to any of the preceding claims, characterized in that the lining material supply means comprise a pump with: a pump housing having a pump housing chamber which can be put under pressure, a pump housing supply inlet for supplying the lining material, and a pump housing discharge outlet for discharging the lining material, the pump housing chamber being in open hydraulic communication with the pump housing supply inlet; at least two delivery chambers, each with a piston movable ^• 5 therein, for varying the volume of the delivery chamber, each delivery chamber being in hydraulic communication, by way of a delivery chamber aperture, with the pump housing chamber; and a pump body which is movable in the pump housing and is provided with a through channel having a first channel aperture

10 and a second channel aperture, which first channel aperture, by movement of the pump body, can be brought into line with one of the delivery chamber apertures as desired, and in which the second channel aperture is constantly in open hydraulic communication with the pump housing discharge outlet.

15 7. Device according to claim 6, characterized in that the pistons in the delivery chambers are single-acting pistons.

8. Device according to claim 6 or 7, characterized in that when the first channel aperture is in line with any delivery chamber aperture, at least one of the other delivery chamber

20 apertures is always in open hydraulic communication with the pump housing chamber.

9. Device according to claim 6, 7 or 8, characterized in that during the transition from one of the delivery chamber apertures to one of the other delivery chamber apertures the pump body

25 blocks a hydraulic communication between the delivery chambers.

10. Device according to any of claims 6 - 9, characterized in that the first channel aperture can additionally be brought into hydraulic communication with the pump housing supply inlet by moving the pump body.

30 11. Device according to any of claims 6 - 10, characterized in that the pump housing is internally of a substantially cylindrical shape, and in that the pump body is shaped like a cylinder segment and is rotatable through a predetermined angle in the pump housing.

35 12. Device according to claim 11, characterized in that the cylinder diameter and the cylinder length of the pump body correspond substantially to the inside diameter and the inside length of the pump housing, respectively.

13. Device according to claim 11 or 12, characterized in that the lining material supply inlet and the lining material discharge outlet are provided at opposite ends of the pump housing.

14. Device according to any of claims 11 - 13, characterized in that the delivery chamber apertures are provided on one of the ends of the pump housing.

15. Device according to any of claims 10 - 14, characterized in that the pump housing is provided with an aperture which gives access to the pump housing chamber, which aperture is released by the pump body when the first channel aperture of the pump body is in line with the pump housing supply inlet.

16. Device according to any of the preceding claims, characterized in that the formwork is composed of formwork rings which each, viewed in the tangential direction, comprise a number of formwork segments, a wedge-shaped tensioning element which tapers off in the radial direction being fitted between two adjoining formwork segments, and an adjusting device also being provided for moving the tensioning element inwards and outwards substantially in the radial direction.

17. Device according to claim 16, characterized in that the adjusting device comprises a screw spindle which is supported in a formwork segment and is connected in a screwable manner to a lug which is provided with a screw thread and is fixed to the tensioning element.

18. Device according to any of the preceding claims, characterized in that the excavating device comprises a head shield and a tail shield situated behind it, which shields are interconnected round the circumference thereof by means of piston/cylinder units.

19. Device according to claim 18, characterized in that the head shield is connected to the formwork by means of a number of double-acting piston/cylinder units disposed round the circumference of said head shield, and in that provision is made for head shield control means which are designed for individually controlling the force produced by each of the piston/cylinder units for propelling the head shield through the ground.

20. Device according to claim 19, characterized in that the head shield control means are designed for setting a pressure point of the total propulsion force supplied by the piston/cylinder units for following a route in the ground.

21. Device according to claim 20, characterized in that the head shield control means are designed to retain the pressure point during retraction of one or more piston/cylinder units when the formwork is being adjusted.

22. Device according to any of the preceding claims, characterized in that the excavating device is provided with an injection ring forming a boundary of the formwork space and having a number of injection apertures placed around its circumference, which injection apertures are in communication with the lining material supply means .

23. Device according to claim 22, characterized in that a flexible sealing ring extending in the formwork space and provided with an interior space is connected to the injection ring, the external dimensions of the sealing ring being adjustable by supplying a fluid to or removing a fluid from the interior space.

24. Device according to claim 22 or 23, characterized in that each injection aperture is connected to a pump, and in that provision is made for pump control means, for controlling the flow rate and the delivery pressure of the respective pumps.

25. Device according to claim 24, characterized in that the pump control means are designed to measure the speed of propulsion of the excavating device, and on the basis of said speed to adjust the flow rate of each pump.

26. Device according to claim 24 or 25, characterized in that the pump control means are designed to measure the ground pressure in the vicinity of each injection aperture, and on the basis of said pressure to adjust the delivery pressure of each pump in accordance with the ground pressure measured at the appropriate injection aperture.