Method for forming a vibration damping screen in the ground

Abstract

 The invention relates to a method for forming a vibration damping screen in the ground, characterised in that a trench (1) is dug at the place where said screen has to be installed, this trench (1) is filled, in a first stage, with a bentonite solution (2), a screen of vibration damping elements (7) is subsequently erected in said bentonite solution (2) and anchored with respect to the bottom of the trench (1) and, in a further stage, the trench (1) is filled with a hardening mass, while the bentonite solution (2) is progressively removed.

Description

[0001] This invention relates to a method for forming a vibration damping screen in the ground.

[0002] The object of the invention is to provide a method allowing to install a screen in the ground which is able to absorb vibrations caused by the transport (and in particular by the train transport) so that no vibrations or insignificant vibrations can be registered behind the screen.

[0003] In order to enable this according to the invention, the method according to the invention is characterised in that a trench is dug at the place where said screen has to be installed, this trench is filled, in a first stage, with a bentonite solution, a screen of vibration damping elements is subsequently erected in said bentonite solution and anchored with respect to the bottom of the trench and, in a further stage, the trench is filled with a hardening mass, while the bentonite solution is progressively removed.

[0004] According to an advantageous embodiment said vibration damping elements are fixed to at least one counterweight and this counterweight is allowed to sink in said trench.

[0005] In a possible variant, said screen is erected by stacking up and mutually connecting elongated vibration damping elements, each of which are provided with a counterweight.

[0006] Other details and advantages of the invention will become apparent from the following description of a method for forming a vibration damping screen in the ground, according to the invention. This description is only given by way of example and does not limit the invention. The reference numerals relate to the figures annexed hereto.

[0007] Figure 1 shows schematically a vertical cross section of a dug trench with a vibration damping screen installed therein.

[0008] Figure 2 is an analogous view (on a larger scale) of a part of a vibration damping screen in a first embodiment.

[0009] Figure 3 is a view relating to a variant of the embodiment according to Figure 2.

[0010] Figure 4 is a schematic top view of the embodiment according to Figure 2.

[0011] Figure 5 is a schematic top view of the embodiment according to Figure 3.

[0012] Figure 6 shows, on a larger scale, a detail of a possible embodiment of a joint between the elements.

[0013] Figure 7 is a perspective view of the suspension of a counterweight to two cables.

[0014] The method for forming a vibration damping screen in the ground comprises digging, in the first step, a trench 1, which is filled immediately with bentonite 2.

[0015] In the schematic view according to Figures 1 and 2, 3 indicates the ground mass wherein the trench 1 is dug, the content of the trench being progressively replaced by a hardening concrete slurry.

[0016] In the trench 1 filled with bentonite or a concrete/bentonite composition, the vibration damping screen is erected. This can be done according to different techniques.

[0017] In the first place, at least one weight 5 is fixed to cables 4, the number of which being facultative. On top of the weight 5, two parallel profiles 6 (for example L-profiles) can be fitted. A membrane, usually known in the technical jargon as "geolock", can possibly be slid in the space between both profiles. Vibration damping elements of a vibration absorbing material are then fixed with respect to the weight 5, and with respect to the cables 4, respectively, and lowered together with this weight to the bottom of the trench 1. The weight 5 may sink by gravity or this weight (or these weights) to which several vibration damping elements are connected may be pulled downwards through the bentonite mass.

[0018] Vice versa, the weights 5 can be pressed downwards together with the elements 7 connected thereto. The techniques applied thereto will not be described here.

[0019] Considered in the horizontal plane, the elements 7 are provided with angle bars 8. The elements situated above each other in a vertical plane are connected by nylon strips.

[0020] A continuous screen with excellent vibration damping characteristics is obtained when in each row stacked elements 7 the lateral edges of the elements 7 show notches 10 and protrusions 11 cooperating therewith. The structure of such elements can be seen very clearly in Figure 6.

[0021] Another way to achieve the continuity of the vibration damping screen is to make use of continuous plates 12 (geolocks), the terminal edges of which show longitudinal profiles engaging into one another. In Figure 6, the ends of such profiles can be seen. One longitudinal profile is the male terminal profile 13 cooperating with the female longitudinal profile 14.

[0022] Preferably the plates 12 (geolocks) consist of high density polyethylene (HDPE) but any other material suited therefor having the same technical properties can be considered in this respect.

[0023] It is to be noted that the terminal edges of the elements 7 are chamfered under such angles that a closely-fitting connection is obtained in this way between the elements arranged next to one another. The terminal edges of the elements 7 are shown in Figure 6. The method according to the invention allows to install vibration damping screens without having to perform digging operations which would occupy, due to the depth, a too large surface on the surface.

[0024] It is clear that the invention is not limited to the embodiments described hereinabove and that a lot of modifications could be applied without falling outside the patent application.

Claims

1. A method for forming a vibration damping screen in the ground, characterised in that a trench is dug at the place where said screen has to be installed, this trench is filled, in a first stage, with a bentonite solution, a screen of vibration damping elements is subsequently erected in said bentonite solution and anchored with respect to the bottom of the trench and, in a further stage, the trench is filled with a hardening mass, while the bentonite solution is progressively removed.

2. A method according to claim 1, characterised in that said screen is erected by stacking up and mutually connecting elongated vibration damping elements fixed to a counterweight.

3. A method according to claim 1, characterised in that said vibration damping elements are fixed to at least one counterweight and this counterweight is allowed to sink in said trench.

4. A method according to any one of the claims 1 - 3, characterised in that said counterweight is anchored with respect to the bottom of said trench.

5. A method according to any one of the claims 1 - 4, characterised in that said counterweight is pulled towards the bottom of the trench together with the vibration damping elements connected successively to each other and to said counterweight.

6. A method according to any one of the claims 1 - 4, characterised in that said counterweight is pressed towards the bottom of the trench together with the vibration damping elements connected successively to each other and to said counterweight.

7. A method according to any one of the claims 1 - 6, characterised in that use is made of vibration damping elements having a longitudinal profile the ends of which show, according to a horizontal cross section, along one extremity a pointed shape and along the other extremity a corresponding notch, in such a manner that the elements can be fitted laterally into one another.

8. A method according to any one of the claims 1 - 6, characterised in that a plate, extending vertically in the operative position and showing the height of the screen to be installed, is anchored in each counterweight, and vibration damping elements are applied on both sides of said plate, which elements are connected to each other and to said counterweight.

9. Vibration damping elements to be used for forming a vibration damping screen in the ground according to the method in conformity with one or more of the claims 1 - 8, characterised in that they have, along the terminal edges which are vertical in the use position and directed towards one another, profiles fitting into one another according to a horizontal cross section.

10. Vibration damping elements according to claim 9, characterised in that they are provided with means by which they can be connected, on the one hand, to said counterweight, and, on the other hand, to each other.

11. Vibration damping elements according to either one of the claims 9 and 10, characterised in that they further consist of a plate of vibration damping material destined for being connected to a counterweight according to the longitudinal symmetry plane thereof and of means for providing said plate along both sides with vibration damping elements.

12. Vibration damping elements according to claim 11, characterised in that said plates show laterally, i.e. in the use position, locking means along both vertical edges, by which two plates disposed next to one another can be slid into one another.

13. Vibration damping elements according to either one of the claims 11 and 12, characterised in that said plate is made of high pressure polyethylene or a technically equivalent material.

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