Stopper for ballastless railway superstructure and manufacturing method therefore

Abstract

Railway superstructure (100) comprising: a concrete foundation (2), at least one prefabricated slab (1) arranged on the upper surface (20) of the foundation (2) and comprising at least one pouring opening (13), a stopper (6) arranged in the pouring opening (13) of the prefabricated slab to constrain the prefabricated slab (1) to the foundation (2), and coupling means (7) arranged in the pouring opening (13) of the prefabricated slab between the stopper (6) and the prefabricated slab (1) to provide a quick coupling / uncoupling between the stopper (6) and the prefabricated slab (1).

Description

[0001] The present patent application for industrial invention relates to a railway superstructure and to a manufacturing method of said railway superstructure.

[0002] The term "railway superstructure" refers to the structural complex that supports the railway tracks whereon trains run. Superstructure systems can be classified into ballasted superstructure systems and ballastless superstructure systems.

[0003] In particular, the present invention relates to the construction of ballastless railway superstructures.

[0004] For a very long time, railway superstructures were built by laying a bed of stone, which was known as "ballast", whereon wooden or concrete slabs, or sleepers, were laid to form the support and fixing surface for the tracks. More recently, the slabs used to support and secure the rails are no longer laid on a ballast, but on a concrete foundation, possibly with an intermediate layer. In such a case, reference is made to ballastless railway structures.

[0005] Prefabricated slabs with quadrangular shape are fixed to the underlying foundation by means of stoppers that prevent the longitudinal and transverse movements of the slabs.

[0006] In particular, the function of the stopper is to prevent any possible movement of the prefabricated slabs under the action of horizontal, longitudinal, and / or transverse forces generated on the track by the movement of the train (snaking, acceleration, and braking, as well as centrifugal forces in curves).

[0007] In order to create a housing for the stopper, a seat is formed in the center of the prefabricated slabs. Such a housing can have various shapes, such as a truncated conical, truncated pyramidal, or cylindrical shape.

[0008] The most common manufacturing technology of said stoppers provides for making a cast on site, using metal bars that are generally made of steel. In particular, the metal bars are inserted into the seat of the prefabricated slab and grouted in the concrete of the underlying foundation. Subsequently, concrete is poured directly into the seat created in the prefabricated slab in order to anchor the metal bars in the concrete.

[0009] The use of a stopper with such a construction is impaired by some drawbacks related to the impossibility of replacing the prefabricated slab easily without demolishing the stopper.

[0010] In fact, if the stopper is made by grouting the bars in the concrete of the foundation and by pouring concrete directly into the seat created in the prefabricated slab, it is impossible to remove the slab without demolishing the stopper.

[0011] In particular, the slab can only be replaced by demolishing the stopper, with the inconvenience of lengthening the replacement time, making replacement operations more difficult, using a higher amount of material, getting the area dirty and having to restore the anchoring of the bars.

[0012] The purpose of the present invention is to overcome the drawbacks of the prior art by providing a ballastless railway superstructure comprising a prefabricated slab that can be easily and quickly replaced without demolishing the stopper.

[0013] Another purpose of the present invention is to provide such a ballastless railway superstructure that is durable, reliable, quick and easy to install.

[0014] These purposes are achieved in accordance with the invention with the characteristics of the appended independent claim.

[0015] Advantageous embodiments of the invention appear from the dependent claims.

[0016] Further features of the invention will become clearer from the detailed description below, which refers to a purely illustrative, non-limiting embodiment illustrated in the appended drawings, wherein: Fig. 1 is a perspective view of a railway superstructure according to the invention; Fig. 2 is a top view of the railway superstructure of Fig. 1; Figs. 3 to 9 are cross-sectional views of the railway superstructure of Fig. 2, taken along the section plane A-A of Fig. 2, schematically illustrating the stepby-step installation of the railway superstructure according to the invention; Fig. 6A is an enlargement of the detail enclosed in circle A of Fig. 6; and Fig. 10 is a cross-sectional view of the railway superstructure of Fig. 2, taken along the section plane A-A of Fig. 2, schematically illustrating the uncoupling between a prefabricated slab and a stopper of the railway superstructure according to the invention.

[0017] With the aid of the attached Figures, a railway superstructure according to the invention, which is generally indicated with reference numeral 100, is described.

[0018] With particular reference to Fig. 1, the railway superstructure (100) comprises a concrete foundation (2), comprising a bottom surface (21) suitable for being disposed on a ground, and an upper surface (20), opposite to the bottom surface (21).

[0019] The railway superstructure (100) also comprises one or more pieces of railway equipment arranged one after the other, each comprising a prefabricated concrete slab (1) arranged on the upper surface (20) of the foundation (2).

[0020] The prefabricated slab (1) has a quadrangular shape and comprises a bottom face (10) facing the upper surface (20) of the foundation (2), and an upper face (11) opposite to said bottom face (10). Moreover, the prefabricated slab (1) has two longitudinal side faces (14) parallel to each other. Fastening systems (M) are arranged on the upper face (11) of the prefabricated slab whereon sections of rails are suitable for being coupled by means of coupling means.

[0021] The railway superstructure (100) comprises adjusting means (3) configured to raise the prefabricated slab (1) relative to the upper surface (20) of the foundation (2), in such a way to generate a cavity (I) (shown in Figs. 3 to 6) between the foundation (2) and the prefabricated slab (1).

[0022] Preferably, said adjusting means (3) comprise adjustment feet (30) for supporting the prefabricated slab (1) in a raised position with respect to the upper surface (20) of the foundation (2).

[0023] Each adjustment foot (30) comprises a screw (31) and a plate (32). The screw (31) of the adjustment foot is suitable for being inserted into a hole (12) made in the prefabricated slab (1) and screwed into a respective nut drowned in the concrete of the prefabricated slab in correspondence with the hole (12). The plate (32) of the adjustment foot is removably attached to the prefabricated slab (1). By way of example, the plate (32) is glued to the bottom face (10) of the prefabricated slab (1) in correspondence with the threaded hole (12) by means of adhesives, such as glue or the like.

[0024] Each plate (32) is suitable for being detached from the prefabricated slab (1) due to the thrust provided by the screw (31) to the plate (32) during the screwing of the screw (31). So the plate (32) is pressed by the screw (31) against the upper surface (20) of the foundation.

[0025] The function of the plates (32) is to prevent the foundation (2) from being demolished during the screwing of the screw (31), i.e. during the adjustment of the height of the prefabricated slab (1).

[0026] The prefabricated slab (1) comprises one or more pouring openings (13) through which a quick-setting, shrinkage-compensated mortar is poured to form a filling layer (4) (Fig. 7) under the prefabricated slab (1) in the cavity (I) between the foundation (2) and the prefabricated slab (1).

[0027] With reference to Fig. 3, each pouring opening (13) of the prefabricated slab is defined laterally by a side wall (13a). The pouring opening (13) has a truncated-conical shape in cross-section, with a decreasing diameter going from the upper face (11) towards the bottom face (10) of the prefabricated slab. Alternatively, the pouring openings (13) may have a truncated-pyramidal or cylindrical shape.

[0028] As shown in Figs. 1 and 7 to 9, the railway superstructure (100) comprises retaining edges (5) suitable for containing the quick-setting, shrinkage-compensated mortar used to form the filling layer (4) in the cavity (I) under the prefabricated slab (1).

[0029] The retaining edges (5) are suitable for being arranged in contact with the upper surface (20) of the foundation (2) at a distance from the longitudinal side faces (14) of the prefabricated slab (1), in such a way that an operator can see the edges of the quick-setting, shrinkage-compensated mortar that flows out of the cavity (I) and abuts against said retaining edges (5).

[0030] More precisely, spacers are arranged between the retaining edges (5) and the longitudinal side faces (14) of the prefabricated slab (1) and configured to create a gap between the retaining edges (5) and the longitudinal side faces (14) of the prefabricated slab (1). The provision of the gap allows an operator to visually inspect and check the condition and level of the layer of quick-setting material poured in the cavity (I). In particular, due to the provision of such a gap, an operator can check both the level of the layer of quick-setting material poured in the cavity (I) and the hardening of the quick-setting material.

[0031] The retaining edges (5) have a higher height than the cavity (I), in such a way to completely contain the quick-setting, shrinkage-compensated mortar poured into the cavity (I).

[0032] Advantageously, the retaining edges (5) consist of metal partitions comprising an ending portion in contact with the foundation (2) and equipped with a rubber gasket.

[0033] With reference to Fig. 8, the railway superstructure (100) comprises stoppers (6) arranged in each pouring opening (13) of the prefabricated slab to constrain the prefabricated slab (1) to the concrete foundation (2) . Therefore, the pouring openings (13) of the prefabricated slab coincide with the seats for housing the stoppers (6).

[0034] Each stopper (6) consists of a concrete body (60) embedding metal bars (61) grouted in the concrete of the foundation (2) and protruding superiorly from the filling layer (4) in such a way to be positioned inside the pouring opening (13) of the prefabricated slab. The metal bars (61) are generally made of steel.

[0035] With reference to Figs. 8 and 6A, coupling means (7) are arranged in the pouring opening (13) of the prefabricated slab between the stopper (6) and the prefabricated slab (1) to provide a quick coupling / uncoupling between the stopper (6) and the prefabricated slab (1).

[0036] The coupling means (7) comprise: two truncated conical elements (70, 71) that are internally hollow and arranged in the pouring opening (13) of the prefabricated slab; and support means (72) for supporting the two truncated conical elements (70, 71) in a raised position with respect to the upper surface (20) of the foundation (2).

[0037] The two truncated conical elements (70, 71) are arranged coaxially and comprise an outer truncated conical element (71) fitted onto the outer surface of the inner truncated conical element (70) in such a way that the outer truncated conical element (71) can slide on the inner truncated conical element (70). The two truncated conical elements (70, 71) are arranged in the pouring opening (13) of the prefabricated slab, one inside the other, so that a cavity (11) is created between the outer truncated conical element (71) and the side wall (13a) defining the pouring opening (13) of the prefabricated slab.

[0038] Each truncated conical element (70, 71) has a height substantially equal to the depth of the pouring opening (13) of the prefabricated slab.

[0039] With reference to Fig. 1A, each truncated conical element (70, 71) comprises an upper opening (70a, 71a) flush to the upper face (11) of the prefabricated slab, and a lower opening (70b, 71b) flush to the lower face (10) of the prefabricated slab. Each truncated conical element (70, 71) is tapered going from the upper opening (70a, 71a) towards the lower opening (70b, 71b).

[0040] Returning to Figs. 8 and 6A, the support means (72) comprise a support plate arranged on the upper face (11) of the prefabricated slab in correspondence with the pouring opening (13) of the prefabricated slab. The support plate comprises a central hole (72a) having a diameter approximately equal to the diameter of the upper opening (70a) of the inner truncated conical element (70).

[0041] With reference to Fig. 6A, the support plate (72) is connected to the inner truncated conical element (70) by means of screws (73) screwed into threaded sleeves (74) welded to the inner surface of the inner truncated conical element (70). In such a way, the support plate (72) supports the inner truncated conical element (70) and the outer truncated conical element (71) fitted onto the inner truncated conical element (70) in a raised position with respect to the upper surface (20) of the foundation (2).

[0042] Moreover, the coupling means (7) comprise a gasket (8) mounted on the outer truncated conical element (71) at the lower opening (71b) of the outer truncated conical element. The gasket (8) is configured to abut against the side wall (13a) defining the pouring opening (13) of the prefabricated slab, in such a way to inferiorly seal the cavity (11) created between the external truncated conical element (71) and the side wall (13a) of the pouring opening (13). The gasket (8) may be made of EPDM rubber.

[0043] Optionally, the coupling means (7) may comprise centering means (75) for centering the truncated conical elements (70, 71) in the pouring opening (13) of the prefabricated slab.

[0044] With reference to Figs. 3 to 9, a manufacturing method of the railway superstructure (100) according to the invention is described below.

[0045] Firstly, the method provides for pouring the foundation (2) on site with automatic machines used to prepare and cast concrete on the ground.

[0046] The prefabricated slab (1) is arranged on the upper surface (20) of the foundation, with the plates (32) glued to the bottom face (10) of the prefabricated slab (1) and interposed between the prefabricated slab (1) and the upper surface (20) of the foundation (2). Subsequently, the prefabricated slab (1) is raised from the foundation by means of the adjusting means (3), so that the cavity (I) is created between the bottom face (10) of the prefabricated slab (1) and the upper surface (20) of the foundation (2).

[0047] The raising of the prefabricated slab (1) is adjusted by means of a set of screwing steps of the screws (31) into the threaded holes (12) of the prefabricated slab. The screwing steps comprise: a first screwing of the screws (31) into the threaded holes (12) of the prefabricated slab until the screws (31) abut against the plates (32); a second screwing of the screws (31) into the threaded holes (12) of the prefabricated slab, so that each screw (31) exerts a thrust on the plate (32) such as to overcome the adhesive resistance provided by the adhesive means, detach the plate (32) from the prefabricated slab and press the plate (32) against the upper surface (20) of the concrete foundation; a third screwing of the screws (31) into the threaded holes (12) of the prefabricated slab, so as to raise the prefabricated slab (1) relative to the upper surface (20) of the foundation.

[0048] Once the prefabricated slab (1) has been raised relative to the foundation below, creating the cavity (I) between the bottom face (10) of the prefabricated slab (1) and the upper surface (20) of the foundation, the retaining edges (5) that have been previously installed in the prefabricated slab (1) are positioned.

[0049] The retaining edges (5) are lowered and placed in contact with the upper surface (20) of the foundation (2). At this point, spacers are placed between the retaining edges (5) and the longitudinal side faces (14) of the prefabricated slab (1), so that a gap is provided between the retaining edges (5) and the longitudinal side faces (14) of the prefabricated slab (1).

[0050] Once the retaining edges (5) have been positioned, at the pouring openings (13), holes are drilled in the foundation (2) for the positioning of the metal bars (61) that will form the reinforcement of the stopper (6).

[0051] Subsequently, the metal bars (61) are positioned into the holes drilled in the foundation (2) and grouted into the concrete. Then the holes drilled in the foundation (2) are sealed with resin.

[0052] Now, the manufacturing method of the railway superstructure (100) provides for inserting the two truncated conical elements (70, 71) into the pouring opening (13) of the prefabricated slab. Advantageously, lubricating material is placed between the inner truncated conical element (70) and the outer truncated conical element (71) with a dual function. In fact, on the one hand, the lubricating material prevents dust and debris from the outside from entering between the inner truncated conical element (70) and the outer truncated conical element (71) and, on the other hand, the lubricating material facilitates the sliding of the outer truncated conical element (71) on the inner truncated conical element (70), when required.

[0053] In particular, the two truncated conical elements (70, 71) are arranged coaxially in the pouring opening (13) of the prefabricated slab, one inside the other, so that the cavity (11) is created between the outer truncated conical element (71) and the side wall (13a) defining the pouring opening (13) of the prefabricated slab.

[0054] In order to ensure that the inner truncated conical element (70) and the outer truncated conical element (71) fitted onto the inner truncated conical element (70) are kept in a raised position with respect to the upper surface (20) of the foundation (2), the support plate (72) is placed on the upper face (11) of the prefabricated slab at the pouring opening (13) of the prefabricated slab. The support plate (72) is connected to the inner truncated conical element (70) by means of screws (73) screwed into the threaded sleeves (74) welded to the inner surface of the inner truncated conical element (70).

[0055] The gasket (8) is mounted on the outer truncated conical element (71) at the lower opening (71b) of the external truncated conical element, so as to inferiorly seal the cavity (11) provided between the external truncated conical element (71) and the side wall (13a) of the pouring opening (13) of the prefabricated slab.

[0056] Advantageously, the support plate (72), the inner truncated conical element (70), the outer truncated conical element (71), the screws (73), the threaded sleeves (74), and the gasket (8) (Fig. 6A) are pre-assembled before being positioned in the pouring opening (13) of the prefabricated slab.

[0057] At this point, the method provides for pouring a bedding layer of quick-setting, shrinkage-compensated mortar inside the pouring opening (13) of the prefabricated slab, until the cavity (I) provided between the bottom face (10) of the prefabricated slab (1) and the upper surface (20) of the foundation is filled, thus creating the filling layer (4). The gasket (8) prevents the bedding mortar from rising inside the cavity (11), i.e., out of the outer truncated conical element (71). Instead, part of the quick-setting shrinkage-compensated mortar rises inside the inner truncated conical element (70) through the lower opening (70b) of the inner truncated conical element (70), thus anchoring the inner truncated conical element (70) to the filling layer (4) and, consequently, to the foundation (2). During the pouring of the bedding layer, the operator can see the edges of the quick-setting, shrinkage-compensated mortar that flows out of the cavity (I) and abuts against the retaining walls (5), in order to check both the level of the layer of quick-setting material poured in the cavity (I) and the hardening of the quick-setting material.

[0058] Once the filling layer (4) has been completed, a first pouring of concrete or other material, such as, for example, fine concrete, resin, or mortar, is made in the pouring opening (13) of the prefabricated slab, up to the upper opening (70a) of the internal truncated conical element (70), so that the stopper (6), that is to say the concrete body (60) embedding the metal bars (61) grouted in the concrete of the foundation (2) and protruding above the filling layer (4), is created in the inner truncated conical element (70). It should be noted that the holes housing the metal bars (61) are made in advance in the foundation (2) in such a way that the metal bars (61) are arranged in the portion of the pouring opening (13) suitable for being enclosed by the inner truncated conical element (70) in order to be successively embedded into the concrete body (60) of the stopper (6).

[0059] At this point, the support plate (72) is removed from the prefabricated slab and a second casting of concrete, or other material, such as, for example, concrete, resin, or mortar, is made in the cavity (11) between the external truncated conical element (71) and the side wall (13a) of the pouring opening (13) in order to anchor the external truncated conical element (71) to the prefabricated slab.

[0060] The manufacturing method of the superstructure (100) according to the invention is now completed.

[0061] With reference to Fig. 10, a process for removing the prefabricated slab (1) is described below.

[0062] When the prefabricated slab (1) is raised, the outer truncated conical element (71) slides over the inner truncated conical element (70). In particular, during the raising of the prefabricated slab (1), the internal truncated conical element (70) anchored to the filling layer (4) and, consequently to the foundation (2), does not interfere with the external truncated conical element (71) anchored to the prefabricated slab (1), thus not generating constraints or forces that oppose the raising of the prefabricated slab (1). Therefore, the prefabricated slab (1) is removed together with the external truncated conical element (71), the gasket (8), and the concrete pouring made in the cavity (11) between the external truncated conical element (71) and the side wall (13a) defining the pouring opening (13) of the prefabricated slab. Instead, the stopper (6) anchored to the internal truncated conical element (70) remains in position with respect to the foundation (2), thus allowing it to be reused.

[0063] Therefore, due to the particular configuration of the coupling means (7) arranged in the pouring opening (13) of the prefabricated slab, between the stopper (6) and the prefabricated slab (1), the prefabricated slab can be removed from the foundation in a single, simple and quick step.

[0064] Numerous variations and detailed modifications can be made to the present embodiment of the invention, within the reach of a person skilled in the art, however falling within the scope of the invention as expressed by the appended claims.

Claims

1. Railway superstructure (100) comprising: - a concrete foundation (2) comprising a bottom surface (21) suitable for being disposed on a ground, and an upper surface (20) opposite to the bottom surface (21). - at least one prefabricated slab (1) arranged on the upper surface (20) of the foundation (2); said prefabricated slab (1) comprising a bottom face (10) facing the upper surface (20) of the foundation (2), an upper face (11) opposite to said bottom face (10), and fastening systems (M) arranged on the upper face (11) and whereon sections of rails are suitable for being coupled by means of coupling means; said prefabricated slab (1) comprising at least one pouring opening (13) defined laterally by a side wall (13a); - a stopper (6) arranged in the pouring opening (13) of the prefabricated slab to constrain the prefabricated slab (1) to the foundation (2); said stopper (6) comprising a concrete body (60) embedding metal bars (61); characterized by the fact that it further comprises coupling means (7) arranged in the pouring opening (13) of the prefabricated slab between the stopper (6) and the prefabricated slab (1) to provide a quick coupling / uncoupling between the stopper (6) and the prefabricated slab (1); wherein said coupling means (7) comprise: - two truncated conical elements (70, 71) that are internally hollow and arranged coaxially, one inside the other, in the pouring opening (13) of the prefabricated slab; said two truncated conical elements (70, 71) comprising an inner truncated conical element (70) and an outer truncated conical element (71) fitted on the outer surface of the inner truncated conical element (70), so that a cavity (11) is created between the outer truncated conical element (71) and the side wall (13a) defining the pouring opening (13) of the prefabricated slab; each truncated conical element (70, 71) comprise an upper opening (70a, 71a) facing the upper face (11) of the prefabricated slab, and a lower opening (70b, 71b) facing the lower face (10) of the prefabricated slab; each truncated conical element (70, 71) is tapered going from the lower opening (70b, 71b) toward the upper opening (70a, 71a); and - a gasket (8) mounted on the outer truncated conical element (71) at the lower opening (71b) of the outer truncated conical element; said gasket (8) being configured to abut against the side wall (13a) defining the pouring opening (13) of the prefabricated slab, in such a way to seal the cavity (11) inferiorly.

2. The railway superstructure (100) according to claim 1, further comprising adjusting means (3) configured to raise the prefabricated slab (1) relative to the upper surface (20) of the foundation (2), in such a way to generate a cavity (I) between the foundation (2) and the prefabricated slab (1); said cavity (I) accommodating a filling layer (4).

3. The railway superstructure (100) according to claim 2, wherein said coupling means (7) further comprise support means (72) for supporting the two truncated conical elements (70, 71) in raised position relative to the upper surface (20) of the foundation (2).

4. The railway superstructure (100) according to claim 3, wherein the support means (72) comprise a support plate located on the upper face (11) of the prefabricated slab, at the pouring opening (13) of the prefabricated slab; said support plate comprising a central hole (72a) having a diameter approximately equal to the diameter of the upper opening (70a) of the inner truncated conical element (70).

5. The railway superstructure (100) according to claim 4, wherein the inner truncated conical element (70) comprises threaded sleeves (74) welded to the inner surface of the inner truncated conical element (70), and the support plate (72) is connected to the inner truncated conical element (70) by means of screws (73) that are screwed into said threaded sleeves (74) welded to the inner surface of the inner truncated conical element (70).

6. The railway superstructure (100) according to any one of the preceding claims, wherein each truncated conical element (70, 71) has a height substantially equal to the depth of the pouring opening (13) of the prefabricated slab.

7. The railway superstructure (100) according to any one of the preceding claims, wherein the coupling means (7) further comprise centering means (75) for centering the truncated conical elements (70, 71) in the pouring opening (13) of the prefabricated slab.

8. The railway superstructure (100) according to any one of claims 2 to 7, wherein the prefabricated slab (1) comprises longitudinal side faces (14) and the railway superstructure (100) comprises retaining edges (5) arranged in contact with the upper surface (20) of the foundation (2) at a distance from the longitudinal side faces (14) of the prefabricated slab (1) in such a way that a gap is provided between the retaining edges (5) and the longitudinal side faces (14) of the prefabricated slab (1).

9. The railway superstructure (100) according to claim 8, wherein the retaining edges (5) have a height greater than the height of the gap (I).

10. The railway superstructure (100) according to any one of claims 5 to 9, wherein the support plate (72), the inner truncated conical element (70), the outer truncated conical element (71), the screws (73), the threaded sleeves (74) and the gasket (8) are pre-assembled.

11. The railway superstructure (100) according to any one of claims 1 to 10, wherein lubricating material is provided between the inner truncated conical element (70) and the outer truncated conical element (71).

12. Manufacturing process of a railway superstructure (100) according to any one of claims 1 to 11, wherein said process comprises the following steps: - pouring of the concrete foundation (2), - laying of the prefabricated slab (1) on the upper surface (20) of the foundation, - drilling of holes in the foundation (2); - positioning of the metal bars (61) into the holes drilled in the foundation (2), - grouting of the metal bars (61) into the concrete of the foundation (2), so that the metal bars (61) are disposed in the pouring opening (13) of the prefabricated slab; - sealing of the holes drilled in the foundation (2); - insertion of the two truncated conical elements (70, 71) in the pouring opening (13) of the prefabricated slab; wherein said step of inserting the two truncated conical elements (70, 71) provides that the two truncated conical elements (70, 71) are arranged coaxially, one inside the other, and that the gap (11) is created between the outer truncated conical element (71) and the side wall (13a) defining the pouring opening (13) of the prefabricated slab; - positioning of the gasket (8) on the outer truncated conical element (71) at the lower opening (71b) of the outer truncated conical element, so as to inferiorly seal the gap (11) provided between the outer truncated conical element (71) and the side wall (13a) of the pouring opening (13) of the prefabricated slab; - realization of a first concrete pouring into the pouring opening (13) of the prefabricated slab, up to the upper opening (70a) of the inner truncated conical element (70), so that the stopper (6), that is to say the concrete body (60) embedding the metal bars (61) grouted in the concrete of the foundation (2), is realized in the inner truncated conical element (70); - realization of a second concrete pouring in the gap (11) between the outer truncated conical element (71) and the side wall (13a) of the pouring opening (13), so as to anchor the outer truncated conical element (71) to the prefabricated slab.

13. The process according to claim 12, wherein the step of inserting the two truncated conical elements (70, 71) into the pouring opening (13) of the prefabricated slab (1) provides for positioning lubricating material between the inner truncated conical element (70) and the outer truncated conical element (71).

14. The process according to claim 12 or 13, wherein the following additional step is provided after the step of positioning the prefabricated slab (1) on the upper surface (20) of the foundation and before the step of drilling holes in the foundation (2): - raising of the prefabricated slab (1) from the foundation (2) by means of the adjusting means (3), so that the gap (I) is formed between the lower face (10) of the prefabricated slab (1) and the upper surface (20) of the foundation; the following additional steps are provided after the step of inserting the two truncated conical elements (70, 71) in the pouring opening (13) of the prefabricated slab and before the step of positioning the gasket (8) on the outer truncated conical element (71): - raising relative to the upper surface (20) of the foundation (2) by positioning the support plate (72) on the upper face (11) of the prefabricated slab, at the pouring opening (13) of the prefabricated slab, - connection of the support plate (72) to the inner truncated conical element (70) by means of screws (73) that are screwed into the threaded sleeves (74) welded to the inner surface of the inner truncated conical element (70), so that the support plate (72) holds the two truncated conical elements (70, 71) in raised position relative to the foundation; the following additional step is provided after the step of positioning the gasket (8) on the outer truncated conical element (71) and before the step of making a first concrete pouring into the pouring opening (13) of the prefabricated slab, - realization of a bedding pouring with quick-setting compensatedshrinkage mortar into the pouring opening (13) of the prefabricated slab, until the gap (I) provided between the lower face (10) of the prefabricated slab (1) and the upper surface (20) of the foundation is filled, so as to create the filling layer (4); the following additional step is provided after the step of making a first concrete pouring into the pouring opening (13) of the prefabricated slab and before the step of making a second concrete pouring into the gap (11) between the outer truncated conical element (71): - removal of the support plate (72) from the prefabricated slab.

15. The process according to any one of claims 12 to 14, wherein the following further step is provided after the step of raising the prefabricated slab (1) from the foundation (2) by means of the adjusting means (3): - positioning of the retaining edges (5) in contact with the upper surface (20) of the foundation (2) at a distance from the longitudinal side faces (14) of the prefabricated slab (1), so that a gap is provided between the retaining edges (5) and the longitudinal side faces (14) of the prefabricated slab (1).

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