Patent Application
20120024970
The present invention relates, generally, to a method for carrying out construction work underneath roadways or railways without interrupting the traffic.
More specifically, the present invention relates to a method for eliminating road and railway line intersections by providing a bottom passage structure outside of its final location and arranging it in position by means of displacement or thrusting of inserted caisson elements, while ensuring continuous communication above the intersection.
It is known in the state of the art to eliminate an intersection level crossing by means of the prefabricated construction of a bottom passage underneath the intersection and its installation using the thrusting or inserted caisson technique.
Elimination of the level crossing at an intersection comprises at least the following operations: manufacture and arrangement of the caisson, provision of a receiving surface, after construction of the caisson outside of its final location, which is as close as possible to the final receiving surface for the inserted caisson, in order to reduce the distance which the caisson must travel and in any case must be equal to the length of the caisson plus the space needed to house the thrusting wall or reaction wall for the thrusting forces and the hydraulic thrusting jacks.
After performing the aforementioned tasks which will be performed by means of the method which is most suitable in each case and which will be determined by the ground and space available, the next step involves construction of a reinforced-concrete sliding sill, with lateral guiding rails at the base of the caisson, the function of which will be to prevent lateral displacement of the caisson.
The sill has a dual function: on the one hand to create a sliding surface for the caisson and, on the other hand, to act as a formwork for the construction of the associated caisson.
At the most distant end of the intersection the reaction wall intended to withstand the thrust of the hydraulic jacks is constructed.
In each case, the dimensions of both the sill and the reaction wall and the number of jacks depend on the weight of the caisson to be pushed into position.
Once the wall and sill have been constructed and after the setting time for the concrete used, a sheet of polyethylene or similar material of a certain thickness is extended over the latter, this having the function moreover of separating the sill of the caisson which is to be constructed from the sliding sill and reducing horizontal friction during displacement, which is of fundamental importance during the initial stage thereof.
During the forward thrusting operation it is necessary to move the support point of the hydraulic jacks, namely construct successive counter thrusting slabs depending on the displacement of the caisson. The function of the counter thrusting slabs is to ensure correct transmission of the force.
The slabs of the highly reinforced constructed caisson have different functions: the bottom one for supporting a travel way allowing the passage of vehicles, trains, pedestrians, etc., and the top one for supporting the traffic of vehicles, trains, pedestrians, etc.
The caisson has a form with a number of rib-like ties at the front thereof, the purpose of which is to provide the least possible resistance to the forward movement against the ground and secure it laterally, for which reason said stirrups are chamfered in their plane of contact with the ground; at the top thereof it has a number of auxiliary beams, the function of which is to brace the ribs and act as a support point for the manoeuvring beams.
The inclination of the ribs is determined depending on the angle of contact of the ground and the need to ensure almost simultaneous contact of the ribs and the bottom slab with the ground.
The support beam situated at the front end of the ribs and seated inside the grooves of both ties has the function of providing a support for transverse metal sections which are arranged underneath the sleepers and in the thrusting direction. Generally the transverse supports are composed of fastened pairs of beams of the IPN type in the form of a “II” which are arranged depending on the slant and separated from each other 1.20 m to 2.40 m between the axes. Usually several pairs of fastened sections are mounted above the caisson.
The transverse support, i.e. fastened sections, have the function of supporting the associated track and transmitting the loads of the rolling stock which travel on the rails and create a surface below which the caisson is slid.
In order to ensure sliding between caisson and fastened sections, round members are arranged between the latter and the top of the caisson in order to facilitate said sliding movement and the fastened sections are braced at the start of the thrusting movement so that they are not subject to any movement with the continuous displacement of the caisson.
Sometimes it is necessary to position wood wedges between the transverse supports and the cross ties, these having the function of ensuring the correct level or elevation of the track during insertion of the caisson.
Moreover, longitudinal shoring is provided above each railway track, consisting in arranging a pair of sets or series of tracks parallel to each track line, fixed by a clamp on both sides of the track line and braced by a number of perpendicular sections or tracks which fix together both sets, supporting at the same time the load of the tracks at the moment when, for working requirements, the support provided by the ballast is no longer present.
Therefore it is required to develop a method for insertion of a caisson which allows the trains to pass through more rapidly than hitherto while displacement of the caisson from the construction location to its final location is being performed, forming a lower passage of a railway line.
EP 1 621 671 A2 discloses a modular system for provisionally supporting working railway tracks during under-track works. In order to carry out infrastructures such as underpasses under the railway tracks a number of rails are arranged in a parallel arrangement with respect to the railway track, the rails being inferiorly connected to each other by a transversal rail section, this system being nevertheless hard to implement and lacking in solidity. The modular system of the invention comprises a plurality of loadbearing crossbeams being arranged in an inferior and transversal arrangement with respect to the railway track rails, the loadbearing crossbeams being parallel to the crossties, and a number of pairs of longitudinal staying beams being arranged in a parallel arrangement with respect to the railway track rails in the middle area between them and at both their sides, said staying beams resting on the plurality of loadbearing crossbeams, the loadbearing crossbeams and the staying beams being joined together by means of lowerable steel blocks.
In the same way, DE 1 205 575 B and ES 2 151 364 A1 disclose supporting arrangement intended to be arranged in a shoring zone of railway track where number of rails are arranged in a parallel arrangement with respect to the railway track, the rails being inferiorly connected to each other by a transversal rail section.
The present invention aims to eliminate or palliate one or more of the abovementioned drawbacks by means of a supporting arrangement as claimed in claim 1. Embodiments of the invention are defined in the dependent claims.
One object of the invention is to provide a shoring system for railway lines in the insertion zone which avoids the use of transverse supports, or fastened sections, above the top part of a caisson which is being inserted in position.
Another object of the invention is to avoid the installation of the longitudinal shoring assemblies which are at present used, assembly and disassembly of which is relatively time-consuming.
Another object of the invention is to provide a self-supporting shoring arrangement which avoids interruption of the railway traffic during assembly and disassembly thereof.
Yet another object of the invention is to reduce the duration of the process for moving the caisson since the railway track is self-supporting and the installation of transverse supports above the top part of the caisson is not required. As a result, the completion times for the whole work are reduced.
A more detailed explanation of the invention is provided in the following description based on the accompanying drawings in which:
Below, with reference to
One of the advantages of the present invention consists in the elimination of the fastened sections 11 of metal beams, which ensures at all times correct positioning of the railway track, below which construction of a passage below the railway is performed.
With reference now to
The set of first longitudinal beams 12 is braced by a second set of perpendicular metal beams 14, with a length less than the first longitudinal beams 12, which fix together both first longitudinal beams 12. Joining of each first longitudinal beam 12 to a second beam 14 is performed via a mechanical fixing means 15 such as a tie, flange, clamp or the like (see
The fixing system 15 has the function of joining one end of the second beam 14 to a first longitudinal beam 12 on the outer side of the railway line 17. Consequently travel of the trains through the shoring zone is not necessary since, in order to perform the shoring work before insertion of the caisson, it is not necessary to occupy the space between railway lines 17.
With reference now to
The spacing between two second perpendicular beams 14 will correspond to a minimum distance substantially equivalent to the width of a sleeper 16 and a predetermined maximum distance corresponding to the width of several sleepers 16 and the spacing between the sleepers will be based on the rolling stock travelling along the tracks.
Where necessary it is possible to add wedges to the second perpendicular beams 14 in order to maintain the elevation of the track in the shoring zone.
With reference now to
Preferably, the first longitudinal metal beam 12 may be a hollow beam, with flanges having cavities 13 which may be circular, hexagonal, octagonal or the like, or a beam of the type with an H or double T profile, with flanges which are wide enough so that it is possible to form in the flanges sets of parallel through-holes and in which the holes of one flange are aligned with the holes of the other opposite flange (see
In this latter case cavities 13 will be formed, spaced from each other on the basis of the distance separating, from each other, the second perpendicular beams 14 which brace the first longitudinal beams 12.
The cross-section of the cavities 13 to be formed will depend on the cross-section of the second perpendicular beam 14 which braces the first longitudinal beams (see
With reference now to
The length of the shoring arrangement must be such as to allow the excavation necessary for displacement of the caisson to be inserted. Consequently, in order to achieve the aim of supporting the track and transmitting the loads travelling along the rails it is possible to position adjacent various shoring arrangements as described above, since in order to obtain the best possible result the length of the first longitudinal beams 12 corresponds to a predetermined maximum length.
The embodiments and examples described in this document are intended to provide the best explanation of the present invention and its practical implementation and allow in this way persons skilled in the art to put into practice and use the invention. Nevertheless, persons skilled in the art will recognize that the description and the above examples have been provided for the purposes of illustration and solely by way of example. The description as provided is not intended to be exhaustive or to limit the invention to the precise embodiment described. Many modifications and variations are possible on the basis of the above teaching without departing from the underlying principle and scope of the following claims.
