EP0967334B1 - Sealing mat for the building of a fluid-impervious layer in the soil - Google Patents

Abstract

A mat for waterproofing ground layers, e.g. under construction or on embankments, has two paper layers (12,14) linked by cross walls (16) also of paper to form parallel chambers (22) which are filled with a mineral sealant. The most common sealant is bentonite which swells when taking up water and which can absorb between 350 and 600 percent of its own weight of water. The upper layer of paper (14) is more porous than the lower layer (12). The side walls are made of similar paper as the upper layer, to spread any water. In its dry state the mats can be supplied in rolls each sufficiently lightweight to be carried by one person.

Description

The present invention relates to a roll-up sealing mat for producing a liquid-tight one Layer in the ground.

Liquid-tight layers for forming a seal in the ground are used in different ways Areas used, such as in landfill construction, in the creation of biotopes, pond and Water systems and when connecting structures in the water area. Especially with small ones areas to be sealed, such as when creating small biotopes, pond or Water systems, however, each of the known sealing methods has disadvantages.

The typical layer structure using such liquid-tight layers is first explained on the basis of the installation of a landfill or a large water system. After the excavation of the the basin and embankments to be sealed are compacted. Then swellable, mineral sealing material applied. Clay-like substances such as clay flour are suitable for this, Clay sealants and the like. This group of materials also includes those for these purposes excellently suited bentonites, of which different types with different swelling and Water absorption properties are commercially available and are representative of the following Clay flour that can be used for sealing purposes is mainly referred to. The angry one Bentonite layer - usually about 1 to 2 cm thick - is at least 20 to 30 cm thick Covering layer covered to form a load that counteracts the swelling pressure that the Water supply swelling bentonite creates. Through the cover layer is also a Damage or erosion of the bentonite layer due to erosion is prevented. With this type The maximum slope angle at the edges must not be used in the manufacture of the sealing layer be greater than about 20 ° because the greater the slope of the slope, the risk of slipping Bentonite would be too large and the tightness could not be guaranteed. Such a However, a lower permissible slope angle leads in particular to small biotope or pond systems to the fact that a disproportionately large proportion of the total area There is no slope area or the plant due to the limited space available cannot be built with the desired depth. This is especially the case with smaller systems from Very disadvantageous for private individuals.

Various sealing mats are also known, in which there is a full area between two needled layers of synthetic fiber nonwoven or glass wool a bentonite layer is incorporated. Such mats that can be rolled up into a roll can be installed on steeper slopes, however the bentonite layer that can be incorporated is relatively thin, which can either lead to tightness problems or the use of the highest quality, i.e. very swellable, and therefore very expensive bentonite or the laying of two mats on top of each other. In addition, there are many people who want to create near-natural ponds or biotopes, aware that the use of such mats plastics used is ecologically problematic.

Ecological concerns also speak against the use of plastic films for the Sealing, which also have the disadvantage that they have to be welded at the joint, to ensure the tightness. Such welding is on the one hand time-consuming, i.e. it requires an additional step, and it is also lacking for private individuals Experience and suitable equipment are often difficult to implement.

In the publication by Saathoff / Ehrenberg with the title "Seal from the Roll" in the issue 9/1992 From ", bd 'baumaschinendienst" it is mentioned that the production of bentonite-filled corrugated cardboard elements for Building seal was known, but without being able to assert itself on the market. such Corrugated cardboard elements filled with bentonite are not for the intended purpose in practice applicable because they are so stiff that - unlike the sealing mats mentioned above - they are not suitable for Transport can be wound up into a roll to be designed on site by unwinding or unrolling to become. In addition, they can only be made in a relatively small thickness, resulting in the same Problems lead, as described in connection with the full-surface needled sealing mats were.

EP-A-0 442 597 discloses a sealing mat comprising: swellable, mineral Sealing material, two with the interposition of the sealing material substantially parallel arranged water-permeable layers, of which a first layer less permeable to water is than the other, second layer, and sidewalls that form the layers more closed connect tubular chambers. The first and second layers are made of fabric, with one the layers are coated with a water-soluble material so that the first layer is less is water permeable than the second layer.

The object of the present invention is to produce an ecological sealing mat to create a liquid-tight layer in the ground that is inexpensive to manufacture, easy to install and can also be used for steep slopes.

This object is achieved with a sealing mat according to claim 1. Advantageous developments of the invention are the subject of the dependent claims.

In the solution according to the invention, the water-permeable layers arranged essentially in parallel and the side walls are made of paper. Bentonite with a water absorption capacity of between 350 and 600% is used, of which so much is arranged in the sealing mat that its weight per unit area is between 10 and 12 kg / m ² . Therefore, the sealing mat can be rolled up very easily and can therefore be easily transported as a roll and easily installed by unwinding. In addition, the sealing mat obtained in this way is relatively inexpensive on the one hand, because it is not necessary to use the most swellable and therefore most expensive bentonite. On the other hand, the weight per unit area required for a secure seal does not require the overall mass of bentonite being too high, which would unnecessarily complicate the transport and laying.

In the following, the case is considered as a typical example that water from above through a an overburden layer located below a bentonite layer. With water supply starts To swell the bentonite layer. In this swelling, bentonite particles are lost due to the swelling pressure in the pores pressed in the overburden layer above close these pores and thus form a seal against further leakage. The swelling process should not for reasons of tightness in any place that is currently damp, but always on that side of the sealing mat start, which faces the expected water supply (in this example the top). In the pond and Biotope construction, the sealing mat is therefore arranged so that the more water-permeable second Layer is on top and thus represents a top layer, while the less water-permeable first layer is at the bottom as a carrier layer. This has the advantage that the swelling of the Bentonite layer always starts from above as desired, even if water does not only come from above, but also reaches the sealing mat from below. This is especially important until the first few days the entire arrangement of the bentonite layer and the overlying load layer is good has set enough.

If after about four to eight weeks the side walls and the first and second layers which are each made of paper, have dissolved, only the swollen remains in the ground Layer of bentonite, which, like all other clay flours, is a natural substance. So it happens by installing a sealing mat according to the invention, no entry of artificial substances in the ground.

The higher water permeability of the second layer compared to the first layer can the second layer paper is more porous than the first layer paper, i.e. that it has larger or more pores than that of the first layer.

For the stability of the sealing layer in the first months after installation, it is advantageous if the second layer, which is usually on top, dissolves faster than when exposed to water the first, usually bottom layer. This intensifies after the start of the dissolution of the Papiers the fact that it is easier to access water from above than from below. Furthermore, this ensures that bentonite particles from the underside of the bentonite layer are not too early can migrate downward due to the swelling process.

The side walls can be designed, for example, so that they do not involve the first and the second layer form tubular chambers which are only open at the end faces. In In this case it is advantageous if these side walls are made of the same paper as the upper, second one Layer are formed, namely from a more water-permeable paper than that of the lower, first layer. Then when exposed to water from above, for example in a garden pond or Biotope, the water also easily penetrate the side walls and thereby the bentonite particles Bring swelling.

Fig. 1

eine perspektivische Darstellung einer in Längsrichtung aufgeschnittenen ersten Ausführungsform der erfindungsgemäßen Dichtmatte,

Fig. 2

einen Längsschnitt durch einen Teil einer zweiten Ausführungsform der erfindungsgemäßen Dichtmatte, und

Fig. 3

einen Längsschnitt durch einen Teil einer dritten Ausführungsform der erfindungsgemäßen Dichtmatte.

Further advantages, features and peculiarities of the invention result from the following description of a preferred, but not restricting, exemplary embodiment of the invention on the basis of the schematic and not to scale drawings. Show it:

Fig. 1

2 shows a perspective illustration of a first embodiment of the sealing mat according to the invention, cut open in the longitudinal direction,

Fig. 2

a longitudinal section through part of a second embodiment of the sealing mat according to the invention, and

Fig. 3

a longitudinal section through part of a third embodiment of the sealing mat according to the invention.

In Fig. 1, the sealing mat cut parallel to the longitudinal axis is shown in perspective, which is designated in its entirety by reference number 10. Between a first layer 12 arranged here below and a second layer 14, here above the first layer, essentially parallel to it, there are a plurality of side walls 16. These side walls 16 are essentially perpendicular to the layers 12, 14 and are at their upper and lower ends connected to the lower layer 12 and the upper layer 14, respectively. This connection can be made, for example, by needling or by means of an ecological glue. As a result, tubular chambers 22 are formed which are filled with sealing material 20. Because of its good swelling and sealing properties, bentonite is used for this reason, which is why bentonite is used as the sealing material in the following. In a typical assembly, such a sealing mat is 3 m long and 1.25 m wide. If so much bentonite is used that it is contained in the sealing mat with a weight per unit area of 10 kg / m ² , this corresponds to a height of the sealing mat of approximately 1 cm. Since the lower layer 12, the upper layer 14 and the side walls 16 are formed from paper, the sealing mat 10 can be rolled up easily. If the dimensions mentioned above are used and the sealing mat is filled with the bentonite mentioned, it has a mass of approximately 35 kg (corresponding to a weight of approximately 350 N). This means that a sealing mat can be rolled up by one person and easily handled on the spot for installation.

As shown in Fig. 1, the side walls 16 extend in the transverse direction of the sealing mat 10, i.e. so perpendicular to their longitudinal direction. They are preferably at a distance of about 1.5 to 2.5 cm from each other. This is advantageous insofar as it results in the inner chamber 22 Bentonite particles located essentially only in the transverse direction of the sealing mat 10, but not in can shift their longitudinal direction. Since the side walls 16 are relatively small Have a distance from each other, the distance between the first remains in the filled state Layer 12 and the second layer 14 largely constant. As a result, the thickness of the sealing mat 10 remains and thus their tightness practically constant over the entire length. 1 is located with respect to the longitudinal direction of the sealing mat 10 at the beginning and at the end Side wall 16 which closes the sealing mat 10 in the longitudinal direction. This also means that the sealing mat the same thickness at the ends. However, the ends can also be formed so that the project lower layer 12 and upper layer 14 over the last side wall 16 and are interconnected.

The embodiment shown in Fig. 2 differs from the first in that Side walls 17 are not, like the side walls 16 of the first embodiment, perpendicular to the lower one Layer 12 and the upper layer 14 are arranged, but that they chambers 23 with a U or V-shaped Form cross section. In the third embodiment according to FIG. 3, the side walls 18 form tubular chambers 24 with an approximately round cross section. Of course they can Chambers also have other cross sections. It is important in any case that they are the unwanted Prevent the bentonite from shifting in the sealing mat.

As stated above, the side walls 16, 17 or 18 and the two layers 12, 14 are formed from paper. Paper, as is known from the production of tea or coffee filters, has proven to be particularly suitable for the production of the second layer 14. A suitable grade has, for example, a basis weight of approximately 16.5 g / m ² , a thickness of approximately 60 μm, a breaking strength in the dry state in the longitudinal and transverse directions of more than 13.0 N / 15 mm or more than 3, 2 N / 15 mm and a breaking force in the wet state in the transverse direction of more than 1.0 N / 15 mm and shows a sand loss of less than 75% with a particle size between 106 and 150 µm. However, papers for the production of serviettes or similar papers are also suitable for the second layer, provided they have specifications similar to those described above.

The first layer 12 is made of less water-permeable paper, which is more stable than the paper second layer 14 is formed. For example, paper for the production of Baker's silk or napkins, which are more stable and waterproof than that for the second layer usable paper, proven, these papers each have a higher breaking strength, but one have less sand loss than the aforementioned papers. The aforementioned papers for the Formation of the first and second layers and the side walls dissolve under the influence of water if also different speeds - slow up and can be biodegraded. Therefore are they can be used ecologically without hesitation.

The sealing material used, namely bentonite, or other clay sealants are naturally occurring and environmentally friendly. The bentonites preferably used for the production of the sealing mat according to the invention are generally known. A typical example of this type of bentonite consists of: montmorillonite approx. 88% (smectite, bentonite), quartz (SiO ₂ ) approx. 4%, calcite approx. 3%, illite approx. 3%, barite approx. 1% , Feldspar about 1%. Of course, depending on requirements, other materials with different compositions can be used to produce the sealing mat according to the invention.

The following is a brief description of how the sealing mat according to the invention is manufactured. First, the sidewalls 16, 17 or 18 are attached to the first layer 12. Then the second layer 14 attached to the side walls 16, 17 or 18. This creates both Tubes 22, 23 or 24 open at the end faces, each with different cross sections after designing the side walls. Then the sealing mat on one end of the Chambers closed, for example by the protruding first layer 12 and second Layer 14 are connected to each other on this end face. Through the opening on the other The chambers are now filled with the bentonite on the front side, after which they are also in on this front side be closed in a similar manner to the other end face. The above Fastening and connection processes can both by gluing using a Ecological glue as well as by needling with a suitable, i.e. biodegradable thread, respectively. The sealing mat now finished can then be rolled up. To dust the To prevent bentonite, the rolled-up sealing mat is used for transport, storage and sale packed in a dust-impermeable film, preferably transparent film.

The sealing mat according to the invention can then be designed on the spot by simply unwinding become. In contrast to the application of the bentonite described at the beginning, this can be done alone bumps, such as smaller stones, are also accepted. Another advantage this sealing mat compared to the needled sealing mats mentioned at the outset is that due to the lower layer of paper, it is more supple and more easily adapted to unevenness in the Adapts to the terrain, which prevents slipping, especially in the slope area. Besides, it's not like when applying the bentonite alone, a well connecting layer immediately above the bentonite required, i.e. this does not have to be clayey. In any case, the surface should be good be compacted in order not to warp more than necessary when a load is later applied and affect the tightness of the layer. To ensure this tightness, it is in the other necessary to have adjacent sealing mats overlap by about 2 to 3 cm. For this It is advisable to arrange a 20 cm thick load layer on the sealing mat, so that too There is a load on the overlap points that is strong enough to withstand the resulting Counteract the swelling pressure of the bentonite. (For the non-overlapping areas of the sealing mat an approximately 10 cm thick load layer would be sufficient.)

The spatial configuration of the sealing mat is not based on the exemplary embodiments specified above limited. For example, the hose-like chambers 22, 23 and 24 can be replaced by a additional partition extending in the longitudinal direction of the sealing mat can be divided. At this The arrangement of these tubular chambers is then already after the second one has been applied The layer is only open on one face side, through which it can be filled with bentonite. Such an intermediate wall makes the bentonite in the chambers even stronger Prevented from slipping. However, the chambers can also be in the longitudinal direction of the sealing mat instead of in their transverse direction, which is why a sealing mat designed in this way in longer Slope areas can be laid out parallel to the slope and not laid perpendicular to it got to. Therefore, it does not have to be cut off as often and - especially when the embankments are not too high be overlapped.

In addition to the mentioned uses in biotope, pond, garden and landscaping the sealing mat according to the invention also for example in green roofs and House wall drying or drying can be used. It may also be advantageous to less water-permeable first layer at the top and the more water-permeable layer at the bottom to be arranged if the water entry from below and not as in the previous examples of is expected at the top and the swelling process should begin at the bottom.

Claims (4)

1. A sealing mat which can be rolled up and which, when rolled up, can be transported by a person for creating a liquid-proof layer in the ground, comprising
      swellable, mineral sealing material (20),
      two water-permeable layers (12, 14) positioned essentially parallel on either side of the sealing material (20), a first layer (12) being less water-permeable than the other, second layer (14), and
      lateral walls (16; 17; 18) which connect the layers (12, 14), thereby forming closed, hose-like chambers (22; 23; 24),
      both the layers (12, 14) and the lateral walls (16; 17; 18) being made of paper, and bentonite with a water absorption capacity of between 350 and 600 % being used as the sealing material (20), its surface weight in the sealing mat lying between 10 and 12 kg/m².
2. A sealing mat in accordance with claim 1 in which the paper of the second layer (14) is more porous than the paper of the first layer (12).
3. A sealing mat in accordance with claim 1 or 2 in which the second layer (14) is more quickly soluble under the effect of water than the first layer (12).
4. A sealing mat in accordance with one of the preceding claims in which the lateral walls (16; 17; 18) are made of the same paper as the second layer (14).

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