DESCRIPTION

The invention relates to a connection system between prefabricated segments for the construction of a modular ring for tunnels, pipelines and the like.

The subject matter of the invention is also a modular ring comprising a similar connection system.

The technical area of the invention is that of tunnels made by mechanical excavation, i.e. through the use of tunnel boring machines (TBM), i.e. solid section mechanical milling cutters, also known as ‘mechanical moles’.

Such solid section mechanical milling cutters have revolutionised the tunnel construction system, enabling the mechanisation and sequential performance of many excavation activities thanks to the particular configuration of the machine.

One of the fundamental characteristics of this type of excavation machines is the capacity to position directly in place a series of modular covering rings that constitute the tunnel.

Such modular rings are comprised of reinforced concrete prefabricated parts known in technical jargon as “segments”.

For the composition of a tunnel, the segments are mutually constrained in the tangential direction for the construction of a modular ring, and an extension direction of the tunnel of which they are a part for fixing with another analogous adjacent modular ring.

The positioning of the segments that comprise the rings that form the tunnel takes place with the aid of a machine known as an ‘erector’. The operator with the joystick moves the segments until reaching the correct alignment between an insert projecting from the segment to be positioned and a corresponding tubular element of the segment already installed, which tubular element is shaped to house the insert of the segment being assembled.

To facilitate the operator during the segment alignment step, on the sides of the segments that are positioned in the substantially longitudinal direction with respect to the extension direction of the tunnel, cavities are defined for housing corresponding ‘guide bars’, i.e. tubular bodies, generally made of recycled PVC, configured to promote and speed up the alignment, and therefore the correct positioning, of the segments during the assembly steps. The guide bars also have the task of withstanding the shear actions that arise between two adjacent segments between which they are interposed.

Once the positioning of all the segments that compose a modular ring of the tunnel has been completed, in order to guarantee the static nature of the ring and the closure of the longitudinal joints, fixing systems with steel screws are currently used.

A similar fixing system for fixing a first segment and a second adjacent segment envisages the use of:

- a screw,

- on a first segment: a substantially tangential through hole defined to enable the passage of the stem of the screw,

- still on the first segment: a tangential inclined hollow, or housing pocket, on the bottom of which is the through hole, which tangential inclined hollow is shaped so that when the stem of the screw is definitively positioned the head of the screw does not project from the internal surface of the segment;

- a tubular element, shaped to be coupled with the stem of the screw, buried in the second segment.

In the case of plumbing or drain tunnels, the housing pockets cause the drawback of substantially increasing the roughness of the tunnel, increasing load losses and reducing the performance levels of the pipeline.

Another drawback of such modular rings consists in the fact that, generally, to join two adjacent segments in the tangential direction, two fixing systems are used, with the consequent need to perform two screwing operations; such screwing operations, within the context of the installation of an entire tunnel, impose a significant use of time and labour.

Another limit of known fixing systems is connected with the need to construct the lateral cavities on the segments for housing corresponding ‘guide bars’ and constructing such guide bars, as well as the installation and use of such alignment assembly for two adjacent segments.

In fact, both the construction of such guide bars, and their installation, are operations that impose relatively significant production costs and times in terms of use.

The task of the present invention is that of developing a connection system for prefabricated segments for modular rings for the construction of tunnels and the like able to overcome the aforementioned drawbacks and limits of the prior art.

In particular, an aim of the invention is that of developing a modular ring for tunnels and the like, which comprises such connection system.

Another aim of the invention is that of developing a connection system that enables tunnels to be constructed whose internal surfaces cause lower load losses with respect to analogous tunnels known to date and therefore that enables the construction of tunnels with improved performance levels with respect to analogous pipelines of the known type.

A further object of the invention is that of developing a connection system that enables the assembly of the modular rings, and therefore the completion of a tunnel or of a pipeline, more simply and quickly with respect to the prior art. Again, an object of the invention is that of developing a connection system that does not require lateral alignment devices, of the lateral guide bar type described above.

Another aim of the invention is that of developing a modular ring comprising a connection system as per the main task.

The task and the aims cited above are reached by a connection system for prefabricated segments for modular rings for the construction of tunnels, pipelines and the like according to claim 1 , and a modular ring comprising such connection system according to claim 10.

Further characteristics of the connection system according to claim 1 are described in the dependent claims.

The aforesaid task and objects, together with the advantages that will be mentioned hereinafter, are indicated by the description of an embodiment of the invention, which is given by way of non-limiting example with reference to the attached drawings, where:

- figure 1 represents a connection system according to the invention integrated into two prefabricated segments being part of a modular ring, also according to the invention;

- figure 2 represents a schematic perspective view of a tunnel made with a series of modular rings according to the invention;

- figure 3 represents a perspective view of a first component of the connection system according to the invention; - figure 4 represents a perspective view of a second component of the connection system according to the invention;

- figure 5 represents a perspective view of a third component of the connection system according to the invention;

- figure 6 represents a plan view from above of the second component of figure 4;

- figure 7 represents the sectional view according to the line of section VII-VII of figure 6;

- figure 8 represents the sectional view according to the line of section VIII-VIII of figure 6;

- figure 9 represents a front view of the second component of figure 5;

- figure 10 represents a lateral sectional view according to the line of section X-X of figure 9;

- figures 11 to 13 each schematically exemplify a use step of the connection system according to the invention;

- figure 14 represents a view from above of a first connection step between segments through a connection system according to the invention;

- figure 15 represents a detail of figure 14;

- figure 16 represents a view from above of a second connection step between segments through a connection system according to the invention;

- figure 17 represents a detail of figure 16;

- figure 18 represents the second component of the connection system according to the invention, in an embodiment thereof, and in a first use step of the connection system;

- figure 19 represents the second component in the variant of figure 18, in a second use step of the system according to the invention;

- figure 20 represents a view from above of the first use step of the connection system comprising the second component in its embodiment of figure 18;

- figure 21 represents a detail of figure 20;

- figure 22 represents a view from above of a second use step of the connection system comprising the second component in its embodiment of figure 18.

With reference to the cited figures, a connection system for prefabricated segments for modular rings for the construction of tunnels, pipelines and the like according to the invention is indicated overall with number 10.

Such connection system 10 comprises:

- a first prefabricated segment 11 ,

- a second prefabricated segment 12, where each of such first segment 11 and second segment 12 are to be considered to have, as well represented in figure 1 :

- four perimeter faces, respectively the faces 13, 14, 15, 16 for the first segment 11, and the faces 17, 18, 19, 20 for the second segment 12;

- an inner face 21 and 22 respectively, i.e. a face turned towards the inside of a modular ring 60 of which the prefabricated segments 11 and 12 are a part, as per figure 2;

- an outer face 23 and 24 respectively, i.e. a face turned towards the outside of the modular ring 60 of which the prefabricated segments 11 and 12 are a part.

The inner face 21 and 22 and the outer face 23 and 24 have the respective surfaces shaped according to a portion of cylinder.

Such inner and outer faces are obviously to be considered to also be able to have a different shape, according to different lines of curvature, or to be able to have hollows or reliefs of various technical functionalities, according to the needs and requirements.

The perimeter faces comprise:

- a front face 13 and 14 respectively, where ‘front face’ means a flat face provided to rest against a flat annular face of a modular ring 60a already defined, as exemplified in figure 2;

- a rear face 15 and 16, where ‘rear face’ means a flat face opposite the front face and provided to receive supportingly a front face of a segment of a modular ring that will be defined below;

- a first lateral face 17 and 18;

- a second lateral face 19 and 20, opposite the first lateral face 17 and 18.

The term ‘lateral faces’ means the perimeter faces that extend between the two front and rear faces of a prefabricated segment.

The peculiarity of the connection system 10 according to the invention lies in the fact that it comprises:

- at least one coupling seat 25, alongside a first lateral face 17 of a first prefabricated segment 11; - a corresponding coupling relief 27, projecting from a second lateral face 20 of a second prefabricated segment 12 arranged alongside the first prefabricated segment 11 with the second lateral face 20 alongside the first lateral face 17.

The coupling relief 27, clearly visible in figures 3, 11, 14 and 15, has a spacer collar 30, exiting from the second lateral face 20, and an anti-extraction coupling head 31, extending from the spacer collar 30 and having a transverse dimension, with respect to an extension direction X1 of said spacer collar 30, that is greater with respect to the corresponding transverse dimension of the same spacer collar 30.

The coupling seat 25, well represented in figures 4 to 10, has:

- an inlet opening 35 configured to enable the passage of said anti-extraction coupling head 31,

- and a slot portion 36, open onto the inlet opening 35, configured so as to enable the sliding of the spacer collar 30 inside it, and configured so as to prevent the slippage of the anti-extraction coupling head 31 in a transverse direction X2 to the translation direction X3 of the spacer collar in said slot portion 36.

In particular, in the present embodiment of the connection system 10 according to the invention, the coupling seat 25 is defined in a coupling body 80.

Such coupling body 80 is made, for example, of plastic material, e.g. PA6, or of metal material, e.g. steel.

Such coupling body 80 comprises anchoring reliefs 81.

Such anchoring reliefs 81 comprise, for example, threaded bars, possibly provided with gripping washers 82.

The coupling body 80 is provided to be housed in a formwork for constructing a prefabricated segment and to be buried in the cast of material of which a prefabricated segment 11 and 12 is made.

The prefabricated segments 11 and 12 are intended to be concrete segments made with known techniques.

The coupling body 80 is therefore incorporated in a prefabricated segment 11 so that the coupling seat 25 defined therein is accessible from a first lateral face 17.

The coupling body 80 comprises a reinforcement plate 83 having, shaped thereon, the inlet opening 35 and the slot portion 36, such reinforcement plate 83 being configured to strengthen the coupling body 80 at the most strained coupling zones between the coupling seat 25 and the coupling relief

27

The coupling body 80 has an outer face 80a shaped so as to extend according to the surface lines of the lateral face 17, 18 which it faces.

In the present embodiment the coupling body 80 has a wedge shape, so that its outer face 80a is arranged on the same lying plane as the first lateral face 17 and 18 of the prefabricated segment 11 and 12, which is inclined by an angle different from 90° with respect to the lying plane of the front 13, 14 and rear 15, 16 faces.

Preferably, two adjacent lateral faces 17 and 20 of two adjacent prefabricated segments 11 and 12 comprise, between one and the other, at least two coupling seats 25 and 26 and the same number of corresponding coupling reliefs 27 and 28.

In the embodiment described herein, which is to be considered a non-limiting embodiment of the invention, the connection system 10 comprises two coupling seats 25 and 26 on said first lateral face 17 and two corresponding coupling reliefs 27 and 28 on the facing second lateral face 20.

An embodiment in which a first lateral face of a first segment has a coupling seat 25 and a coupling relief 27 is also to be considered comprised in the invention, whereas the second lateral face of the second adjacent segment has a coupling relief 28 intended to be connected with the coupling seat 25 of the first segment and a coupling seat 26 intended to be connected with the coupling relief 27 also of the first segment.

Each prefabricated segment 11 and 12 has on each of its lateral faces 17, 18, 19, 20 at least two from among a coupling seat 25, 26 and a coupling relief 27,

28

In an embodiment not illustrated, but to be considered comprised in the invention, the connection system can comprise only one coupling seat on a lateral face of a first segment and only one coupling relief on a lateral face of an adjacent second segment.

In the present non-limiting embodiment of the invention, the first 11 and second 12 prefabricated segments comprise:

- two coupling seats 25, 26 and 25a’, 26a respectively, on a first lateral face 17 and 18 respectively; - two coupling reliefs 27a, 28a and 27, 28 respectively, on the opposite second lateral face 19 and 20 respectively.

Figure 4 represents a coupling relief 27, it being understood that the other mentioned coupling reliefs 28, 27a and 28a are the same.

The coupling relief 27 is integrated into an insert 40, which insert 40 comprises a fixing shank 42.

Advantageously, such insert 40 comprises a central centring portion 41, which can be clearly seen in figure 3.

Such central centring portion 41 is, for example, sphere shaped.

As can be clearly seen from the figures, and in particular from figures 3 and from 11 to 13, the sphere shaped central centring portion 41 has a larger diameter than the diameter of the spacer collar 30 and than the fixing shank

42

The sphere shaped central centring portion 41 has a smaller diameter than the diameter of the anti-extraction coupling head 31.

Alternatively, such central centring portion may be truncated cone shaped. Again alternatively, such central centring portion is shaped like two opposing truncated cones.

Such central centring portion 41 causes the alignment of the two prefabricated segments between which the insert 40 is interposed and withstands the shear forces that develop between such two prefabricated segments between which the insert 40 is interposed.

As can be clearly seen from figures 3 and from 11 to 13, the insert 40 is defined by a single body comprising the coupling relief 27, the central centring portion 41 and the fixing shank 42.

The insert 40 is made of plastic, or composite, material or of other similar and equivalent materials.

The coupling seat 25 has a tapered wall 25a to guide the insertion of the coupling head 31.

The central centring portion 41 cooperates with such tapered wall 25a in order to gradually recover the correct mutual angular arrangement between the segments during the connection steps.

The term ‘tapered wall’ is to be understood, as can be clearly seen in figures 4 and from 6 to 13, as meaning that the tapered wall 25a defines a passage space, for a coupling relief 27, having a passage section that is narrowed from the outer face 80a of the coupling body 80 towards the reinforcement plate 83 which is located on the bottom of the coupling seat 25, as can be clearly seen in figures 6 to 10.

The coupling relief 27 extends from the central centring portion 41 on the opposite side with respect to the fixing shank 42, and in particular according to a diametrically opposite direction.

In the embodiment of the invention described herein, obviously by way of non-limiting example of the invention, the fixing shank 42 is comprised by a threaded stem.

In an alternative not illustrated, such fixing shank has a knurled surface, or radial gripping ribs.

The connection system 10 comprises, for each insert 40, a tubular plug 44, clearly visible in figure 5, shaped for coupling with a corresponding fixing shank

42

Such tubular plug 44 therefore has an internal thread configured for the screwing of the threaded stem of the fixing shank 42.

Such tubular plug 44 is made of plastic material, e.g. PA6.

Such tubular plug 44, preferably but not exclusively, is of the T25 type.

The tubular plugs 44 are provided to be housed in a formwork for constructing a prefabricated segment, and to be buried in the cast of material with which a prefabricated segment 11 and 12 is made.

Each tubular plug 44 is therefore incorporated into a prefabricated segment 11 and 12 so that the internal thread defined therein can be accessed from a second lateral face 19 and 20, in order to be able to screw an insert 40 therein once the segment is ready.

The connection system 10 according to the invention also comprises front joining means 50 configured to connect the front face 13, 14 of a prefabricated segment with the rear face 15, 16 of another prefabricated segment, according to an extension direction X4 of a tunnel or pipeline 70 of which the prefabricated segments are a part; on this point, see the diagram of a tunnel 70 according to the invention reported in figure 2.

Such front joining means 50 comprise, for example and not exclusively, a plurality of axial reliefs 51 projecting from a front face or from a rear face of a prefabricated segment, and corresponding coupling holes 52 defined on an adjacent rear face or front face of a preceding or subsequent segment in the extension direction X4 of a tunnel 70.

Each of the axial reliefs 51 is integrated into a corresponding second insert 46, which second insert 46 comprises a fixing shank, which fixing shank can be considered analogous to the fixing shank 42 described above.

The prefabricated segments 11 and 12 therefore also comprise tubular plugs 44, as described above, positioned so that the internal thread defined therein is accessible from a front face 13, 14, or from a rear face 15, 16, in order to be able to screw a corresponding insert 46 therein, once the segment is ready.

An axial relief 51 is comprised of a shank with annular gripping ribs, or of a knurled or threaded shank.

The coupling holes 52 advantageously have a truncated cone shaped guide hole 52a to help the insertion of the corresponding axial relief.

Also the second insert 46 has a central centring portion 46a, analogous to what is described above for the insert 40.

The truncated cone shaped guide hole 52a cooperates with the central centring portion 46a of the second insert 46 in order to gradually recover the correct mutual angular arrangement between the segments during the connection steps.

Figures 18 and 19 represent a coupling body 180 for a key segment 111.

Such coupling body 180 has a coupling seat 125 whose inlet opening 135 is configured to enable the passage of said anti-extraction coupling head 31 and of the spacer collar 30 in a direction coinciding with the translation direction X3 of the spacer collar 30 in the slot portion 136.

In particular, the inlet opening 135 is defined on a transverse plane with respect to the plane on which the slot portion 136 is arranged, and in particular at an end 186 of the coupling body 180.

In that case, a prefabricated segment 112 and 112a, as per figures 20, 21 and 22, which is adjacent to a key segment 111, has, for each coupling body 180, a tangential inclined hollow 190, or housing pocket, configured to enable the front approach of the coupling relief 27 at the inlet opening 135.

Thus the assembly of the key segment 111 is enabled with a simple axial movement, i.e. in the extension direction X4 of a tunnel or pipeline 70, avoiding the tangential insertion movement of the coupling relief 27 of the coupling seat 25 described above.

The subject matter of the invention is also considered to include a modular ring 60 for tunnels, pipelines and the like, of the type comprising a plurality of prefabricated segments 11, 12, 61, 62, 63, 111 adjacent to one another in the tangential direction and mechanically connected to one another.

Such modular ring 60 is characterised in that it comprises a connection system 10 as described above for the joining of at least two of said prefabricated segments 11, 12 and preferably for the joining of all the prefabricated segments that compose it.

The subject matter of the invention is also a tunnel, pipeline 70 or the like, comprising a series of modular rings 60, 60a, 60b, 60x according to the invention itself.

Such modular rings 60, 60a, 60b, 60x are preferably connected to one another with front joining means 50 as described above.

The prefabricated segments are to be considered to be of known types:

- segments with parallel faces, that compose the so-called “straight rings”;

- segments with non-parallel, trapezoid or rhomboid shaped faces, forming the so-called “conical rings”.

The shapes of the prefabricated segments are to be considered to be able to be rectangle, trapezoid or parallelogram shaped.

The key segment, the last to be installed in the ring assembly process, is always trapezoid shaped.

It has in practice been established that the invention achieves the intended task and objects.

In particular, the invention develops a connection system that enables tunnels to be constructed whose internal surfaces cause smaller load losses with respect to analogous tunnels known today, thanks to the absence of housing pockets for the heads of the fixing screws, which fixing screws are not used.

A similar connection system therefore enables the creation of tunnels with improved performance levels with respect to analogous pipelines of the known type.

Furthermore, the invention develops a connection system that enables the assembly of modular rings, and therefore the completion of a tunnel or a pipeline, more simply and quickly with respect to the prior art, thanks to the use of quick couplings that do not envisage long and costly screwing operations. Again, the invention develops a connection system that does not need lateral centring devices, of the lateral guide bar type described above, as the gradual centring is performed during the translation step of the coupling relief 27 in the coupling seat 25.

The invention develops a modular ring comprising a connection system as the main task, as well as a tunnel, pipeline comprising a series of such modular rings.

The invention thus conceived is susceptible to many modifications and variants, all falling within the same inventive concept; furthermore, all details can be replaced by other equivalent technical elements.

In practice, the components and materials used, as long as they are compatible with the specific use, as well as the dimensions and the contingent shapes can be whatever according to requirements and the prior art.

Where the characteristics and techniques mentioned in any claim are followed by reference signs, such reference signs are to be intended as having been added for the sole purpose of increasing the intelligibility of the claims and consequently such reference signs have no limiting effect on the interpretation of each element identified by way of example by such reference signs.