WO2014098569A2

WO2014098569A2 - A method of constructing a reinforced earth structure comprising one or more cladding elements and a reinforced earth structure comprising one or more cladding elements

Info

Publication number: WO2014098569A2
Application number: PCT/NL2013/000061
Authority: WO
Inventors: Antonius Gijsbertus Johannes Maria VOETS
Original assignee: Voets Gewapende Grondconstructies B.V.
Priority date: 2012-12-19
Filing date: 2013-12-17
Publication date: 2014-06-26
Also published as: WO2014098569A3; EP2935703B1; NL1039968C2; EP2935703A2

Abstract

A reinforced earth structure is constructed from several earth-retaining layers. When applying the layers, anchoring elements (5) are fitted between the layers. Cladding elements (6) are attached to these anchoring elements (5), with, preferably, there being adjusting means (7) between the anchoring means (5) and the cladding elements (6) and a cavity (8) preferably having been formed between a cladding element and the anchoring means.

Description

A method of constructing a reinforced earth structure comprising one or more cladding elements and a reinforced earth structure comprising one or more cladding elements.

The invention relates to a method of constructing a reinforced earth structure and to a reinforced earth structure. Reinforced earth structures are also called stabilized earth structures.

Reinforced earth structures are earth structures in which the earth has been reinforced using reinforcing elements, e.g. steel or geosynthetic materials. Geosynthetic materials may include geotextiles, geogrids, geonets and geomembrames.

Reinforced earth structures are used for such applications as reinforcing unstable slopes and/or are used as bridge ramps, dykes, reinforced slopes, abutments, quays or as parts thereof.

Reinforced earth structures are sometimes provided with cladding elements, often in the form of modular blockwalls comprising concrete panels or gabions for example. The walls of the reinforced earth structure can be finished with such cladding elements for various reasons, e.g. for architectural reasons or for aesthetical or safety considerations.

These cladding elements may get damaged, for example by movements resulting from the settlement of the earth while, or relatively soon after, constructing the reinforced earth structure or at a later time. This may also cause the mutual positions of the cladding elements to shift, resulting in a less taut look.

If any damage has occurred, the damaged cladding elements will have to be replaced.

Replacing a cladding element is costly and time-consuming and may also bring other disadvantages such as a traffic artery having to be closed in order to, replace a damaged cladding element.

An objective of the invention is to reduce the cost and time involved in replacing a damaged cladding element and/or the risk of a cladding element being damaged and/or to obtain a better result. To this end, the method according to the invention is characterized in that formwork is erected after which an earth-retaining layer is provided that contains a flexible casing material and a fill material, with the casing material having a border on a side facing the formwork, after which an anchoring means is placed on the border which anchoring means contains a coupler on a side facing the formwork for coupling the anchoring means to a cladding element after which a next earth-retaining layer is provided, thus securing the anchoring means between the earth-retaining layer and the next earth-retaining layer. In existing methods, the cladding elements are applied during the building process such that they form one whole with the earth structure. The cladding elements have protruding reinforcing elements and the earth is provided around the reinforcing elements connected to the cladding elements. As most settlement occurs while building the earth structure, settlement of the earth causes the cladding elements that are coupled to the earth structure to deform. The reinforcing elements have been integrated into the earth structure, as a result of which their positions are fixed and they have to follow the movements of and in the earth structure. In the method according to the invention, anchoring means are installed between layers of earth, which anchoring means contain couplers to couple the anchoring means to a cladding element.

As is the case in the existing method, settlement will occur in the method according to the invention while constructing the earth structure.

However, in the method according to the invention, the cladding elements are installed later after initial settlement of at least part of the earth has already taken place.

The cladding elements are installed after the earth structure has been constructed and has largely undergone settlement. This reduces the risk of deformation.

Should any damage occur, a cladding element will be easy to replace.

Preferably, a formwork wall is applied that extends over more than one earth-retaining layer. The anchoring means are aligned to the formwork wall when installing them and the formwork wall is removed after several earth-retaining layers have been put in place. The use of a formwork wall that extends past more than one earth-retaining layer and aligning the anchoring means relative to the formwork wall enables the mutual positions of the anchoring means to be determined accurately. This enables more accurate positioning of the anchoring means. For example, the anchoring means can be placed against the formwork wall or at a short, defined distance from that wall. Prior to applying a layer, the formwork wall can be provided with one or more marks that correspond with a desired position for one or several anchoring means. The formwork wall forms a reference plane for the anchoring means. Preferably, adjusting means are attached to the anchoring means in order to set the position of a cladding element coupled to an anchoring means and specifically and preferably in a direction in the plane of the cladding element.

The adjusting means offer more freedom to determine the position of the cladding elements.

The positions of the anchoring means may vary slightly due to further settlement over time.

Since adjusting means that enable the anchoring means to be coupled adjustably to a cladding element have been attached to the anchoring means, the position of the coupler is adjustable and the cladding elements can be installed accurately and the risk of the cladding getting damaged is slight. The position of a cladding element can be readjusted to compensate any settlement that may occur over time after constructing the structure.

A reinforced earth structure according to the invention contains a number of earth- retaining layers with a flexible casing material and a fill material, with the outside of the casing material having a border and with an anchoring means having been installed between two layers on the border, with the anchoring means containing a coupler to couple the anchoring means to a cladding element such that it can be detached.

Adjusting means have preferably been attached to the anchoring means.

A cavity has preferably been formed.

Woven geotextile is preferably used as the flexible casing material.

It is noted that a method where the reinforced earth structure contains a number of layers where rod-shaped distancers are placed between the layers of earth, either while piling the layers of earth on top of each other or after piling by driving in the distancers between layers of earth, is known from EP 1 054 110. The rod-shaped distancers protrude 10 to 15 cm, for example. A large, rigid welded mesh panel is attached on or to the rods from the bottom to the top of the earth structure. A fine meshed material may be applied to an interior side of the coarse-meshed welded mesh panel. The space between the welded mesh panel and the layers of earth is filled with material, for example vegetation soil, gravel, pebbles or concrete. The welded mesh panel keeps the fill material in place. The fill material between the layers of earth and the welded mesh panel may be applied before or after applying the welded mesh panel. The welded mesh panel's position is fixed once the fill material has been applied.

A structure where L-shaped elements from reinforcing material are placed in front of the layers of earth to reinforce the structure is known from EP 0 603 460. A part of the L- shape is clamped between layers of earth in some examples. The space between the L-shaped parts and the layers of earth is then filled up.

These and further aspects of the invention are described below and illustrated by means of the drawing:

The figures contained in the drawing show the following:

Figure 1 shows a step in the method according to the invention;

Figure 2 shows a next step;

Figure 3 shows a further step;

Figure 4 shows a front view of a reinforced earth structure according to the invention;

Figure 5 shows a front view of a reinforced earth structure according to the invention with a cladding element;

Figure 6 shows a side view of a reinforced earth structure according to the invention with a cladding element before the cladding element has been secured;

Figure 7 shows a side view of a reinforced earth structure according to the invention with a cladding element after the cladding element has been secured;

Figure 8 shows a reinforced earth structure according to the invention with a cladding element after the cladding element has been secured;

Figure 9 shows another embodiment of a method according to the invention;

Figure 10 shows a side view of another embodiment of a reinforced earth structure according to the invention; Figures 11 and 12 show a further example of a detail of an earth structure according to the invention;

Figures 13 and 14 show an example of an adjusting means. The figures are exemplary figures, wherein, as a rule, like numerals denote like elements.

Figure 1 shows a step in the method according to the invention. A formwork wall 1 is placed near, for example, a slope 2 that is to be reinforced. A first earth-retaining layer containing a flexible casing material 3 and fill material 4 is provided. An anchoring means 1 is placed on the border on the side facing the formwork wall 1. The anchoring means can be placed against the formwork wall or at a short distance from that wall.

Figure 2 shows a next step: a next earth-retaining layer containing a flexible casing material 3' and fill material 4' is applied and a next anchoring means 5' is placed on the border of 3' and on the side facing the formwork wall 1.

These steps are repeated, see figure 3, until a reinforced earth structure of the required height has been constructed.

Please note that an upright formwork wall 1 is shown in this example.

The formwork wall may also be placed at an angle and while constructing the earth structure different formwork walls may be used at different heights. The different earth- retaining layers may be constructed of similar materials, but it is also possible that consecutive layers have different compositions, e.g. that they contain another fill material 4. In this way the bottom layer can be made to be different from the top layer.

Figure 4 shows a front view of a reinforced earth structure according to the invention. Anchoring means 5 have been fitted in a number of places. The example shown is an example and must not be considered to impose any restrictions; different anchoring means patterns are possible; some anchoring means directly under each other, a staggered pattern, a zigzag pattern and other patterns. A cladding element 6 is installed against the earth structure and attached to the couplers 7 of anchoring means 5, as shown schematically in figures 5 and 6.

The cladding elements 6 may consist of or contain various materials: Concrete

Steel

Timber

Plastic

- Glass

Gabions

The above list is not intended to be an exhaustive list. Embodiments may make use of cladding elements of a relatively slight strength and thickness. Since the cladding elements have not been incorporated directly in the earth structure, their thickness and, as a result, weight can be decreased. Lightweight cladding elements result in a C0₂ reduction because less energy and, consequently, less C0₂ are required both to manufacture the cladding elements and to supply and install the cladding elements. Figure 6 shows a next step: adjusting means 7 are secured to the anchoring means 5. Once installed, the adjusting means are located between the cladding element 6 and the anchoring means 5.

Figure 7 shows the installed structure. Preferably, the adjusting means are such that a cavity 8 is formed between the exterior, indicated as B in figure 8, of the layers and the cladding elements 6. The earth may shift and cause the outside of the earth to bulge out over time. The presence of the cavity prevents or decreases the risk of such bulging to apply pressure to a cladding element 6. Preferably, the cavity is at least 5 cm wide, preferably more than 10 cm and preferably between 10 and 25 cm.

Figure 8 shows an anchoring element 5, which in this example contains an anchoring part 10 and an anchor 11. The front of the anchor 11 is located on the outside B of the earth.

Anchor 11 has been provided with an adjusting means 7 that is attached by means of bolts for example. This adjusting means 7 is connected to the cladding element 6. In this example, the cladding element contains a plate 12 in a hole bigger than plate 12 that can be attached to the adjusting means 7. The adjusting means preferably has means that enable adjustment in the X and Y directions, i.e. directions in the plane of the cladding element. This makes the position of a cladding element in the plane of the cladding element adjustable. The look of a wall that shows a number of cladding elements is also determined by their mutual positions and then often particularly by distances between cladding elements. Even a relatively minor variation in distances may be visible. The human eye is susceptible to this. Adjusting means that enable a cladding element to be moved in the plane of the cladding element enable the distances between cladding elements to be adjusted.

Means to make adjustment possible in the Z-direction, i.e. transversally to the plane of the cladding element, to adjust the width of the cavity, also form part of a preferred embodiment.

The anchoring part 10 may contain geogrid, plastic strips, steel strips or rods, which may be galvanised and/or provided with a profile. The length and strengths of such parts can be adjusted to the requirements.

Preferably, the anchoring part contains a geogrid since a geogrid offers a high degree of friction and, consequently, better anchoring.

The adjusting means 7 may contain a filler plate to align the cladding element as well as a mounting plate. Furthermore, the adjusting means 7 may contain an anchor rail and slotted holes to provide margins within which the position of the cladding element can be adjusted both in a vertical and in a horizontal direction, i.e. the X and Y directions.

The adjusting means may depend on their positions, for example adjusting means that have to carry a relatively high weight may be constructed more heavy than adjusting means that have to carry a relatively low weight.

The method and earth structure according to the invention offer high security and great flexibility for the design and look of the earth structure. This offers such parties as architects a lot of freedom to achieve their designs. Different cladding elements may be incorporated into a wall of an earth structure. For example, the high degree of flexibility provided by the invention enables solar panels or instruction signs to be used as cladding elements.

Figure 9 shows another embodiment of the invention. This embodiment features separate formwork 11a, l ib, 11c and l id being applied for every layer. An earth-retaining layer is provided in the formwork 1 la, an anchoring means 5 is installed on the border of the flexible material 3, after which formwork 1 lb is installed on the lower earth-retaining layer using anchoring means 5, in which a next earth-retaining layer is applied and a next anchoring means 5, after which formwork 1 lc is installed and so on.

An earth structure according to the invention is constructed on this. The difference between this embodiment and the embodiment shown in figures 1 to 3 is that the formwork 1 la, 1 lb, 1 lc, 1 Id is integrated into the earth structure. The advantage is that this formwork increases the strength of the earth structure to a certain extent. This may be useful in some circumstances. The disadvantage is that the anchoring means 5 are hard to position accurately relative to each other. The advantage of using a form work wall 1 as shown in figures 1 to 3, which can be removed later, is that a reference plane, i.e. the formwork wall is provided for the positions of the anchoring means. This enables the construction to comply with the dimensions specified much more rigidly so that, if adjustment is desired later, there is much less to be adjusted and simpler adjusting means will suffice.

Figure 10 shows an embodiment where the width of the cavity varies, i.e. increases from the bottom up. The invention enables the design to be adjusted to an architect's wishes.

Figures 11 and 12 show another embodiment of the invention. As stated above, the anchoring means 5 may contain steel rods. The anchoring means 5 in this embodiment contain a number of steel, preferably galvanised, rods 13 between the layers of earth. Figure 11 shows a top view, figure 14 a side view. Plates 15 have been fitted to the front ends of rods 13 and an anchor construction 14 is fitted on the rear side of every rod, i.e. on the side located between the layers of earth. An adjusting means 7 extends between the plates and a cladding element 6. The adjusting means keeps the cladding element 6 at a distance from the plates 15, as a result of which a cavity has been formed. The cladding element 6 features a plate 12. The plate has been fitted in a slotted cavity in cladding element 12 where the dimensions of the slotted cavity are larger than the dimensions of plate 12. As shown in figures 13 and 14, the cladding element contains two holes 16 in which the rods can be secured and a slotted hole 17 in which plate 12 can be secured using a sliding bolt and nut construction. The slotted hole and the freedom offered to plate 12 in the cavity in cladding element 6 enable the position of the cladding element to be adjusted in the plane of the cladding element, i.e. in X and Y directions. The plates 15 can be placed onto a threaded end of rods 13 such that the positions of the plates 15 can be adjusted, enabling the cavity width to be adjusted.

In summary, the invention can be described as follows:

A reinforced earth structure is constructed from several earm-retaining layers. When applying the layers, anchoring elements are fitted between the layers. Cladding elements are attached to these anchoring elements, with, preferably, there being adjusting means between the anchoring means and the cladding elements and a cavity preferably having been formed between a cladding element and the anchoring means. It will be clear that the invention enables many variations and that the invention is not limited to the examples described above.

Claims

Claims:

1. A method of constructing a reinforced earth structure characterized in that form work (1, 11a, l ib, 11c, l id) is erected after which an earm-retaining layer is provided that contains a flexible casing material (3) and a fill material (4), with the casing material having a border (3a) on a side facing the formwork (1, 1 la, 1 lb, 1 lc, 1 Id), after which an anchoring means (5) is placed on the border which anchoring means (5) contains a coupler on a side facing the formwork to couple the anchoring means to a cladding element (6), after which a next earth-retaining layer is applied, thus securing the anchoring means (5) between the earth-retaining layer and the next earth-retaining layer.

2. Method as claimed in claim 1 in which a formwork wall (1) is applied that extends over more than one earm-retaining layer, the anchoring means are aligned to the formwork wall and the formwork wall is removed after several earth-retaining layers have been put in place.

3. Method as claimed in claims 1 or 2 with adjusting means (7) being attached to the anchoring means in order to set the position of a cladding element (6) that is coupled to an anchoring means (5).

4. Method as claimed in claim 3, where a cladding element (6) is attached to a number of couplers using the adjusting means (7).

5. Method as claimed in claim 3 where an attached cladding element is detached from the adjusting means (7) and is replaced by another cladding element that is attached to the adjusting means (7).

6. Method as claimed in claim 3 where a cladding element is detached, the position of one coupler is or the positions of several couplers are readjusted using the adjusting means (7) and the cladding element (6) is again attached to the adjusting means (7).

7. A reinforced earth structure comprising a number of earth-retaining layers with a flexible casing material (3) and a fill material (4), with the outside of the casing material having a border and with an anchoring means (5) having been installed between two earth- retaining layers on the border, with the anchoring means containing a coupler to couple the anchoring means to a cladding element such that it can be detached.

8. Reinforced earth structure as claimed in claim 7, with adjusting means (7) having been attached to anchoring means in order to set the position, within the plane of the cladding element, of a cladding element (6) that is coupled to an anchoring means (5).

9. Reinforced earth structure as claimed in claim 8, where a cladding element (6) has been attached to the adjusting means (7).

10. Reinforced earth structure as claimed in claim 9 where a cavity (8) has been formed.

11. Reinforced earth structure as claimed in claim 10 where adjusting means to adjust the width of the cavity have been secured to the anchoring means.

12. A reinforced earth structure as claimed in one of the above claims 7 to 11 , characterized in that the anchoring means contains a geogrid (10).