MOVABLE FORMWORK SYSTEM FOR CLADDING PART OF A TUNNEL

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a 35 U.S.C. § 371 National Stage patent application of PCT/ES2023/070530, filed on 30 Aug. 2023, which claims the benefit of Spanish patent application U202231425, filed on 30 Aug. 2022, the disclosures of which are incorporated herein by reference in their entirety.

TECHNICAL FIELD

The present disclosure relates generally to formwork machinery.

The disclosure provides a formwork system for lining generally vertical surfaces which: reduces construction time and building cost.

The use of the disclosure is particularly advantageous for building mined soft-ground tunnels, for example, in cases where the so-called Belgian tunneling method is recommended.

BACKGROUND

The Belgian method or the traditional method of Madrid for constructing tunnels is a method that is generally used for constructing short excavated soft-ground tunnels and is characterized by being a building method that minimizes the dimensions of the open excavation faces, which is favorable for controlling soil displacements generated during construction and, therefore, reduces the risk of excavation collapse.

The Belgian method for excavating and lining a tunnel is carried out in two main phases: top heading excavation and downward (bench) excavation.

The sequence of operational phases of this building method is as follows:

• • excavation and shoring of a small advance gallery at the crown level,
  • lateral widening and shoring of the advance gallery,
  • installation of formwork and casting of the concrete of the crown,
  • excavation and concreting of the side walls,
  • construction of the invert.

Therefore, in this method, the excavation of the crown is shored and widened gradually to form the complete crown, but with a longitudinal displacement for each widening phase, such that the excavation face is small to ensure excavation stability.

The Belgian method is generally used for constructing short excavated tunnels in grounds consisting of compact clay or clay with a certain percentage of sand, and provides the advantage of reducing the risk of excavation instabilities due to the fact that an excavation of a small crown is performed first.

However, this method is slow and costly since the tunnel must be excavated manually by skilled workers and must be lined in batches or short sections, such that a large number of formwork assembling and disassembling operations is required.

Therefore, it would be desirable to have a formwork system capable of carrying out the tunneling method described above in a more automated manner, in order to reduce the construction time and cost, particularly with respect to the construction of the side walls.

SUMMARY

The disclosure relates to a movable formwork system for lining generally vertical surfaces with concrete, with the expression “generally vertical” being understood as encompassing both surfaces orthogonal to the ground and surfaces with a certain inclination with respect to the ground, be they flat surfaces or slightly curved surfaces.

The disclosure is particularly advantageous for use for lining part of a tunnel, preferably for lining the side walls thereof, although the disclosure is not limited to this particular use, since it could also be used to frame a vertical surface in any other application.

The formwork system comprises a preferably straight, longitudinally elongated guide rail, and fastening means for fastening the guide rail to a surface to be lined, such as to a previously constructed concrete lining, for example part of a tunnel.

The formwork system further comprises a formwork panel coupled to the guide rail by rolling means sliding on a surface of the guide rail.

The rolling means are attached to the formwork panel and may comprise, for example, of sheaves or cylinders sliding on the rail.

The disclosure encompasses various possibilities for placing the guide rail with respect to the formwork panel; therefore, in a preferred embodiment, the guide rail is placed at an upper level of the formwork panel and the formwork panel hangs from the guide rail.

In another preferred embodiment, the guide rail is placed at a lower level of the formwork panel, so the formwork panel is movable on the guide rail.

In another preferred embodiment, the guide rail is placed on one side of the formwork panel.

The formwork system further comprises an anchoring structure having one part attached to the formwork panel and another part projecting from the formwork panel and is configured to be fastened to a surface of the tunnel to be lined. The projecting part of the anchoring structure is located on one side of the formwork panel, specifically on the rear side of the formwork panel, with respect to the direction of movement of the panel when lining a surface, for example part of a tunnel.

In a preferred embodiment, this anchoring structure is formed by two or more beams arranged in the same longitudinal direction of the guide rail, which have a part attached to the formwork panel and another part projecting from the formwork panel.

The formwork system is configured such that the formwork panel along with the anchoring structure can move together with respect to the guide rail, and sliding through the rolling means, when the anchoring structure is not fastened to a surface to be lined.

Furthermore, the formwork system is configured such that the guide rail is movable with respect to the formwork panel when the anchoring structure is fastened to an outer surface.

The lining of a surface, for example, a surface of a tunnel, is performed by concreting consecutive segments, such that with the configuration described above of the formwork system of the disclosure, for placing the formwork panel to form a new segment, the formwork panel is moved to the position in which the new segment will be formed, and the anchoring structure is fastened to the preceding segment with concrete that has already set, so that the panel is correctly fastened and positioned for concreting that segment.

With the formwork panel fastened, the guide rail is removed from the fastening means and moved in a direction of forward movement so as to allow the movement and guiding of the formwork panel for subsequent placements.

Construction time and building costs are reduced with this formwork system. Furthermore, it does not require heavy machinery for handling and positioning the formworks, since they can be moved and positioned with little manpower.

An additional advantage of the disclosure is that it entails a minimal invasion of the inner space of the work site, for example a tunnel, which enables significant transit of people and small machinery compared to the conventional systems to perform lining.

In a preferred embodiment, the formwork panel has a flat surface for the formation of a concrete lining, and the anchoring structure has one or more surfaces coplanar with the flat surface of the panel, so that the anchoring structure can be fastened on the surface of a preceding section of concrete that has already set, and the flat surface of the panel is positioned to form the subsequent lining section.

In an alternative embodiment, the formwork panel can be curved.

In a practical embodiment of the disclosure, a formwork system has at least two sliding formworks like the one previously above, for lining respective sides or side walls of a tunnel at the same time.

BRIEF DESCRIPTION OF THE DRAWINGS

To complete the description and to facilitate a better understanding of the disclosure, a set of drawings is provided. These drawings are an integral part of the description and illustrate an embodiment of the disclosure, which should not be interpreted as restricting the scope of the disclosure, but merely as examples of how the disclosure can be carried out. The drawings comprise the following figures:

FIG. 1 shows respective perspective views 1A, 1B from different angles of one and the same movable formwork system according to the disclosure.

FIG. 2 shows a front view of a tunnel with respective formworks constructing the side walls thereof. This figure includes an enlarged detail of the rolling means.

FIG. 3 shows a longitudinal section according to plane AA in FIG. 2, in a phase of concreting a side wall section.

FIG. 4 shows a depiction similar to the preceding figure in a phase of removing the formwork and moving the panel.

FIG. 5 shows a depiction similar to the preceding figure in a phase of launching the guide rail.

DETAILED DESCRIPTION OF WAYS OF PUTTING THE DRAWINGS

FIGS. 1 and 2 show a movable formwork system for lining part of a tunnel (2), specifically in this preferred embodiment the side walls (3, 3′) of the tunnel, once the crown (4) has been constructed, wherein the system comprises in this practical embodiment respective sliding formworks, a left formwork (1) and a right formwork (1′), which are a mirror image of one another.

The left formwork (1) shown in FIGS. 1A, 1B comprises: a straight, longitudinally elongated guide rail (5), fastening means (6) for fastening the guide rail (5) to an already concreted surface of the tunnel to be lined, in this case for being fastened to the crown (4), and a formwork panel (7) located at a lower level of the guide rail (5) and coupled thereto by means of a pair of tie rods (8) which are attached to the upper edge of the formwork panel (7).

In the embodiment of the disclosure shown in the figures, the formwork panel (7, 7″) is flat and rectangular, so it has a flat surface (14) for the formation of a concrete lining. In other preferred embodiments, the panel (7, 7′) can be curved.

The fastening means (6) for fastening the guide rail (5) comprise a plurality of individual elements which can be fastened, in a removable manner, to the guide rail (5) and to a surface of the tunnel to be lined, for example, by means of bolts and nuts.

The formwork (1) further includes rolling means sliding on a surface of the guide rail (5) and attached to the formwork panel (7), specifically sheaves (9) attached to the tie rods (8).

The formwork (1) has an anchoring structure formed by a group of beams (10) arranged in the same longitudinal direction as the guide rail (5), and having one part attached to the formwork panel (7) and another part projecting from the formwork panel (7), specifically projecting from the rear side (11) of the panel (7) with respect to the direction of forward movement of the panel indicated by the arrow in FIG. 1.

The beams (10) are arranged such that they have surfaces (15) coplanar with the flat surface (14) of the panel (7).

The projecting part of the beams (10) have holes (12) for the fastening thereof to an already concreted prior section, for example, by means of screws (13,13′) as shown in FIG. 2.

FIG. 2 also shows skirtings or counterflashings (16, 16′) attached to the lower edge of the panels (7, 7′), serving as part of an invert (17).

FIG. 3 shows the left formwork (7) while concreting a section (19) of a side wall (3) of the tunnel (2), with the beams (10) being fastened to a front section (18) that has been previously concreted. The circles in the figure depict vibrators (20) in contact with the formwork panel (7), that are commonly used to cause the vibration and compaction of fresh concrete so that it fills the entire volume of the mold.

Once the concrete of the section (19) sets, as shown in FIG. 4, the anchorings in the holes (12) fastening the projecting part of the beams (10) are released, and therefore the panel (7) along with the structure of beams (10) can be moved suspended from the guide rail (5) until being positioned for concreting the subsequent section (21). Once correctly positioned, the projecting part of the beams (10) is again fastened to the previously concreted section (19) and the process is repeated.

In the position of FIG. 4, there is a need to move the guide rail (5) forward, so it is released from the fastening means (6) and moved or launched in direction of forward movement, as indicated by the arrows in FIG. 5 as well as various individual elements of the fastening means (6), to enable moving the panel (7) to the subsequent sections to be concreted.