Geomaterial sheet with biodegradable properties

Description

[0001] The invention relates to a method for soil stabilization using a geomaterial sheet and to the use of a geomaterial sheet for soil stabilization.

[0002] Geomaterial membranes, also known as geotextiles (or classically, geosynthetics), are used in a variety of ways to stabilize soil layers. Typical examples of such diverse applications include slope stabilization, dike construction, bank protection along rivers and lakes, slope stabilization in landfill areas, and the stabilization of road and railway alignments. Geomaterial membranes are generally installed at a predetermined depth, meaning they are covered by soil layers, but in some cases, they can also be installed on the surface.

[0003] The geomaterial sheet serves to stabilize the soil layer and soil boundaries, thus preventing erosion, soil displacement, and mixing; inhibiting or reducing soil material movement, such as that caused by flow-induced erosion and redeposition; and preventing overall soil layer slippage. Geomaterial sheets can be used as a permanent solution, particularly where natural processes like root penetration or other soil stabilization mechanisms are insufficient to stabilize the soil layer or its boundaries.In many applications, geomaterial membranes are installed to achieve a temporary, time-limited mechanical stabilization effect. This stabilizes the soil layer sufficiently to allow plant growth, and further stabilization of the soil layer can be achieved in the long term through root penetration by these growing plants. A geomaterial membrane used as a reinforcing mat is known from EP 2 439 342 A1.

[0004] One problem associated with such geomaterial membranes is that the artificial material introduced into the ground poses a potential environmental risk. This risk can occur at the installation site itself or, if the geomaterial membrane is broken into smaller sections by mechanical influences or other actions and carried away from the installation site, at other locations. To overcome these disadvantages, it has generally been proposed to manufacture geomaterial membranes from biodegradable materials. For example, a cover layer made of a material is known from DE 295 16 797 U1, where the material can consist of natural fibers. US 2013 / 0344759 A1 discloses a geotextile with a non-woven structure in which plant fibers are used for its production. Hemp fibers are proposed as a replacement for previously known jute or coconut fibers.

[0005] From EP3385426A1, a fiber structure material is known which is designed for increased water absorption capacity. The fiber structure of this known material is designed as a three-dimensional fiber framework of interconnected thick and thin fiber sections, which is produced from a lyocell solution. This fiber structure material has the disadvantage that, due to the three-dimensional direct connection of the fiber components to one another, it exhibits uniform biodegradability and therefore does not comprise two structural materials with different biodegradability.

[0006] A textile sealing membrane made of lyocell fibers is known from US2009 / 0317583A1. This sealing membrane does not have two structural materials with different biodegradability.

[0007] A disadvantage of the proposed biodegradable geotextiles is that the desired mechanical soil stabilization is not guaranteed for the required period in many applications. Biodegradation leads to a loss of mechanical protection, and undesirable soil movements such as landslides, dike damage, and the like can occur. While a fiber coating is suggested to avoid these problems, this contradicts the primary goal of achieving biodegradability and creates an environmental risk emanating from the coating. Therefore, the use of biodegradable geotextiles made from the aforementioned known natural fibers cannot yield satisfactory results in many applications or fails to meet the time requirements for mechanical stabilization.For geosynthetics, DIN EN 12225 therefore specifies test criteria to demonstrate general resistance to microbial degradation.

[0008] It is therefore an object of the invention to propose a method for stabilizing soil layers with a geomaterial sheet and uses of geomaterial sheets for stabilizing soil layers which ensure reliable mechanical stabilization over the necessary period of use, while at the same time reducing environmental impact.

[0009] This problem is solved according to the invention by a method for location-dependent soil stabilization using a geomaterial sheet, comprising the following steps: Determining the intensity of an influencing parameter at the installation site, wherein the intensity of the influencing parameter is selected from: intensity of electromagnetic radiation, level of temperature, concentration of a substance that reacts chemically and / or biochemically with the geomaterial sheet, concentration of bacteria, and / or concentration of fungi; determining one or more of these influencing parameters at a delivery site located away from the installation site; installing the geomaterial sheet at the installation site, wherein the geomaterial sheet comprises a structural material that exhibits biodegradability under the intensity of the influencing parameter at the delivery site to such an extent that, within six months, a delivery site residue remains in a 2 mm sieve when the material or its components are sieved; wherein the delivery site residue is less than 30 wt.-% of the material, ∘ exhibits biodegradability at the installation site under the intensity of the influencing parameter to such an extent that within six months an installation site residual fraction of the material remains in a 2mm sieve when the material or its components are sieved, ∘ where the installation site residual fraction is greater than the disposal site residual fraction.

[0010] According to this aspect of the invention, site-dependent soil stabilization is achieved using a geomaterial sheet. This means that the geomaterial sheet has a biological degradation time at the installation site and a different biodegradability at the transport site, which, as before, can be defined, for example, analogously to the standardization of biodegradability according to ISO 16929 or the marine degradation test – but with the parameters determined at the installation site and the transport site, respectively. Under the conditions prevailing at the installation site, after a period of six months or twelve weeks, more than 10 wt.%, in particular more than 25 wt.% or more than 80 wt.% of the structural material can remain as particles in a 2 mm sieve. This results in a reduced biodegradation rate at the installation site, which is sufficient for numerous soil stabilization applications and ensures reliable degradation of the geomaterial sheet.This biodegradability is achieved under the conditions at the installation site, particularly with regard to the aforementioned influencing parameters such as temperature, radiation exposure, oxygen, bacteria and / or fungal concentration, or the like. In contrast, the material exhibits higher biodegradability at a transfer location using the inventive method. Under the conditions at the transfer location, fewer particles of the material remain in a 2 mm sieve after six months or twelve weeks than under the conditions at the installation site. At the transfer location, this can preferably be less than 80 wt.%, 80 wt.%, and in particular less than 25 wt.% or less than 10 wt.% of the structural material within the six months or twelve weeks under the prevailing conditions at that location, with a higher degradation rate.

[0011] The disposal site can be a location where the geomaterial sheet is transported after removal from the installation site, for example, a landfill, and which differs from the installation site with respect to one of its influencing parameters. For instance, the landfill site may have a deliberately created higher oxygen concentration and / or stronger UV radiation and / or higher concentrations of bacteria and / or fungi, thus accelerating the biological degradation of the geomaterial sheet. The disposal site can also be a location where the geomaterial sheet arrives, either whole or in fragments, if it is exposed or mechanically damaged by environmental or other influences and then, for example, becomes exposed, floats, or is transported by other means.A disposal site can also be understood as a situation where the original installation of the geomaterial sheet at the installation site beneath a soil layer changes in such a way that the soil layer is eroded, thereby exposing the geomaterial sheet. This is the case, for example, in many marine applications for coastal protection and scour protection, where water and wave action can cause the material to be separated and transported from the installation site to a disposal site. At the disposal site, the geomaterial sheet degrades more rapidly and therefore does not pose a significant environmental burden.

[0012] It is preferable if the installation site has an environment with a lower temperature, lower oxygen content, and / or lower bacterial and / or fungal concentration compared to the disposal site. These influencing parameters are particularly well suited for viscose-based geomaterial membranes such as lyocell to achieve the desired difference in biodegradation rate between the installation site and the disposal site.

[0013] The installation site can be located on the seabed, and the geomaterial sheet can float to the surface due to currents and / or density differences, or be brought to the surface by anthropogenic influences. The installation site is therefore characterized by higher oxygen concentrations and temperatures in the upper water layers, as well as increased UV radiation, which accelerates degradation.

[0014] It is even more advantageous if the structural material is viscose-based, particularly lyocell. Such a structural material has proven especially suitable for the selectively accelerated biodegradation rates at the delivery site compared to the installation site.

[0015] According to this aspect of the invention, the geomaterial sheet is therefore used in such a way that it comprises a structural material which under a first intensity of an influencing parameter at an installation site, biodegradability is demonstrated to such an extent that, in a composting test with the following parameters: ∘ Samples with a length of 10 cm, a width of 10 cm and an original material thickness ∘ 50°C + / - 5°C o thermophilic conditions according to ISO 16929, unless these are defined by specific intensities of specific influencing parameters at the installation site, ∘ sieving of the solids after six months in a sieve with a 2 mm mesh size (Mesh 8.75), more than 50 dry wt% of the starting material remains in the sieve, or that in a marine incubation test with the following parameters: ∘ Samples with a length of 2 cm, a width of 2 cm and an original material thickness ∘ 30°C + / - 2°C ∘ Aerobic conditions in seawater with a salinity of 3.5 % wt. + / - 1 wt.-%, unless these are defined by specific intensities of specific influencing parameters at the installation site, ∘ Sieving of the solids after 4, 8 and 12 weeks in a sieve with a 2mm mesh size (Mesh 8.75) if, during sieving after 12 weeks, more than 10 dry wt.%, in particular more than 25 dry wt.% or more than 80 dry wt.% of the starting material remains in the sieve, and . under a second intensity of the influencing parameter at a disposal site, biodegradability is such that within six months in the composting test or twelve weeks in the marine incubation test and less than 80 wt.%, in particular less than 25 wt.% or less than 10 wt.% of the dry mass of the first structural material remains in the sieve after sieving through a 2mm sieve, wherein the intensity of the influencing parameter is selected from: an intensity of radiation exposure of electromagnetic radiation, an altitude of a temperature, a concentration of a substance that reacts chemically and / or biochemically with the geomaterial web, a concentration of bacteria, a concentration of fungi, in such a way that the geomaterial track is installed at the installation site at one installation time and transported to the delivery location at a later time following the installation time.

[0016] According to this usage, a geomaterial sheet is deployed in such a way that at its installation site it exhibits a predetermined degradation rate, not exceeding a specific biological degradation rate, which is achieved through the aforementioned prevailing influencing parameters. In contrast, the geomaterial sheet is deployed in such a way that when it is transported from the installation site to a disposal site, which can occur through planned or unplanned transport, it exhibits a higher degradation rate and thus degrades more rapidly at the disposal site compared to the installation site. This accelerated degradation is achieved through the dependence of the degradation rate on a different intensity of an influencing parameter at that location.This is also due to several different influencing parameters that prevail at varying intensities at the installation site and the disposal site – and which are used as influencing parameters in the previously defined material tests for compositeability and marine degradation, respectively, instead of the specified parameters. According to the invention, biodegradability is defined according to the principle of standard ISO 16929 or according to a marine degradation test developed by TÜV Austria Belgium. The material according to the invention must meet at least one of these two conditions, preferably both.

[0017] According to ISO 16929, a material's compostability is demonstrated if it meets three criteria. One of these criteria is defined as follows: after 84 days in controlled composting, no more than 10% by weight of the material remains in a 2 mm sieve when the material or its components are sieved. Based on this system and adapted to the needs of geomaterials, the first structural material exhibits an initial biodegradability if, within six months in controlled composting according to ISO 16929 under thermophilic composting conditions, no more than 50% by weight of the dry mass of the first structural material remains in the sieve after sieving through a 2 mm sieve. Therefore, the first material does not necessarily qualify as compostable according to ISO 16929. However, it may be compostable, or it may achieve the degradation of 90% by weight of particles <2 mm over a period longer than six months.

[0018] The degradation test under marine conditions simulates the degradation of standardized samples under accelerated conditions in seawater. Here, too, the degree of degradation is determined by a final sieving based on the dry weight remaining in the sieve. However, the increased mobility of the material is simulated by two intermediate sievings after 4 and 8 weeks.

[0019] Both degradation tests are performed using specimens with defined dimensions. Length and width are defined, while the thickness is based on the original material, i.e., the thickness of the material in the manufactured structure. For layered composites, where the first and second structural materials are arranged in separate, superimposed layers and bonded together, this can be the thickness of the material in the respective layer. If the original material is produced as a composite layer, such as a nonwoven fabric or as a layer woven, knitted, or otherwise bonded from two different fibers, then a sample of the material with the original thickness of the layer, made exclusively from the material under investigation, must be used for the purposes of the degradation test.

[0020] According to a further aspect of the invention, the problem set out at the beginning is solved by a geomaterial web comprising a first viscose-based fiber material, in particular lyocell.

[0021] According to this aspect of the invention, the geomaterial web comprises a viscose-based fiber. This viscose-based fiber can be used as a first or second structural material in the geomaterial web. In principle, according to the invention, regenerated cellulose fibers such as lyocell are well suited as a material or component of geomaterial webs.

[0022] The geomaterial sheet can consist solely of the initial viscose-based fiber or it can contain additional structural materials, particularly other fibers. A viscose-based fiber can, in particular, be a fabric made of viscose fibers, i.e., generally a fabric made of synthetic fibers derived from regenerated cellulose. Typically, the cellulose is processed as filament yarn or as staple fiber, for example, using wet spinning. According to the inventors, viscose fibers have proven particularly suitable for providing the targeted biodegradation necessary for geomaterial sheets. Thus, the viscose fiber can be adapted to a desired rate of biodegradation under predetermined environmental conditions at the installation site by modifying the fiber length, crimp, and by varying the fiber thickness.Furthermore, viscose fibers are metabolizable by numerous living organisms and can therefore be classified as environmentally harmless.

[0023] A viscose-based fiber material, such as lyocell, can in particular also be used as the first and / or second structural material according to the first aspect of the invention.

[0024] The inventor has identified viscose fibers of the Lyocell type as particularly suitable. These fibers are a type of viscose fiber produced by a solvent spinning process in which the cellulose is dissolved directly in an organic solvent without the formation of a derivative, and the solution is then spun. This manufacturing process, especially when using the organic solvent NMNO (N-methylmorpholine N-oxide), is environmentally friendly both in terms of production and the resulting product. According to the invention, wood pulp can preferably be used as the cellulose starting material.According to the inventors, Lyocell has proven to be biodegradable under typical environmental conditions in soil layers. Its degradation rate is such that, in conjunction with root penetration rates in newly planted areas, the degree of biodegradation of the geomaterial sheet is sufficiently advanced by the time a sufficient root penetration for the mechanical stabilization of a slope is reached. This ensures that root penetration is neither significantly impeded nor are any substantial residual quantities of the geomaterial sheet present over time. Furthermore, the inventors have found that Lyocell is well-suited for differentiated biodegradation. Specifically, Lyocell degrades more rapidly under elevated concentrations of oxygen, bacteria, and / or fungi in the environment and with increased UV radiation than under low concentrations of oxygen, bacteria, and / or fungi and low UV radiation.This allows a geomaterial sheet to be installed as planned for soil stabilization, providing the necessary mechanical properties for soil stabilization at that installation site for the desired period. However, if intentionally or unintentionally moved to another location where different conditions prevail, such as increased oxygen, bacteria, and / or fungal concentrations or UV radiation, it degrades more rapidly. This selectivity of the degradation rate is advantageous, for example, for use on the seabed with low oxygen, bacteria, and fungal concentrations, low temperature, and low UV radiation, as unintentionally floating lyocell or lyocell moved to locations with different environmental conditions will then degrade more quickly.This can also be advantageous in coastal protection and bank stabilization measures, where lyocell, if exposed, is then degraded more quickly due to increased UV radiation and increased concentration of bacteria and / or fungi.

[0025] According to a preferred embodiment, the first fiber material is designed as a nonwoven, knitted, or woven fabric and is processed into a textile fabric within the geomaterial web by mechanical bonding, knitting, or weaving. This type of bonding of the first fiber material results in a resilient geomaterial web that is well-suited for the mechanical loads required for soil layer stabilization. At the same time, this processing method achieves favorable degradation behavior, including the formation of perforations or enlargement of openings, as well as a reduction in mechanical properties. The first fiber material can be bonded to one or more identical fiber materials to form a nonwoven, knitted, or woven fabric.Furthermore, the first fiber material can be combined with a second fiber material to form a nonwoven, knitted, or woven fabric that differs from the first fiber material in terms of material composition or fiber modification. In particular, this allows a first structural material and a second structural material to be combined to form a geomaterial web.

[0026] According to a further preferred embodiment, the first fiber material is processed with a second fiber material, which is different from the first fiber material, to form a textile fabric. Such a textile fabric is made of two different fiber materials or more than two different fiber materials. The textile fabric can be designed as a nonwoven, knitted, or woven fabric, or as a combination thereof.

[0027] It is even more preferred if the first fiber differs from the second fiber by a different fiber thickness, a different chemical composition, a different surface roughness, a different degree of stretching, a different opening or mesh size, a different tensile strength-elongation behavior, a different breaking strength, or a combination of two or more of these properties. According to this embodiment, the first and second fibers differ in one or more of seven properties that influence both the mechanical properties and the rate of biodegradation of the fiber.This design of the textile surface structure ensures that the rate of biological degradation and the mechanical behavior over the service life of the first fiber differ from that of the second fiber, which can be achieved both due to a different material composition (chemical composition) and due to a modification of materially identical fibers.

[0028] According to the invention, the geomaterial sheet described above is used to be embedded in a soil layer for the purpose of soil stabilization. As previously explained, this soil stabilization can serve for slope stabilization, bank stabilization, dike reinforcement in coastal protection, seabed stabilization against scour, and soil stabilization along transport routes. These uses are characterized by the fact that, on the one hand, the biological degradation of the geomaterial sheet at the installation site itself is advantageous and desirable, so that the geomaterial sheet dissolves after a certain degree of root penetration or other soil stabilization has been achieved.Secondly, in these applications, properties of the geomaterial sheet are desired that ensure that, when the geomaterial sheet is moved from the installation site to another location, for example due to mechanical degradation, carried by the wind, floats up or is moved by other currents, it degrades more quickly at this other location compared to the installation site and / or can be metabolized by flora and fauna compared to conventional products.

[0029] Another aspect of the invention relates to the use of a geomaterial sheet comprising a structural material that under a predetermined intensity of an influencing parameter at an installation site, biodegradability is demonstrated to such an extent that in a composting test with the following parameters: ∘ Samples with a length of 10 cm, a width of 10 cm and an original material thickness ∘ 50°C + / - 5°C ∘ thermophilic conditions according to ISO 16929, unless these are defined by specific intensities of specific influencing parameters at the installation site, ∘ sieving of the solids after six months in a sieve with a 2 mm mesh size (Mesh 8.75) less than 50 dry wt% of the starting material remains in the sieve, or in a marine incubation test with the following parameters: ∘ Samples with a length of 2 cm, a width of 2 cm and an original material thickness ∘ 30°C + / - 2°C ∘ aerobic conditions in seawater with a salinity of 3.5 wt. % + / - 1 wt.-%, unless these are defined by specific intensities of specific influencing parameters at the installation site, ∘ Sieving of the solids after 4, 8 and 12 weeks in a sieve with a 2mm mesh size (Mesh 8.75) where, after sieving at 12 weeks, less than 20 dry wt% of the starting material remains in the sieve. wherein the predetermined intensity of the influencing parameter is selected from: an intensity of a radiation effect of an electromagnetic radiation of an altitude of a temperature, a concentration of a substance that reacts chemically and / or biochemically with the geomaterial sheet, a concentration of bacteria, a concentration of fungi, to stabilize a soil layer in flood protection or scour protection.

[0030] According to this aspect of the invention, a geomaterial sheet, in particular a geomaterial sheet of the type described above, is used to achieve soil stabilization for scour protection or flood control. Flood control in this context can refer to any type of bank reinforcement on the seashore, the banks of flowing and standing waters, and lakes, whereby the geomaterial sheet can be positioned below or above the water surface, with the option of being exposed to air or water. In this case, it serves to stabilize the bed, slope, or dike and can be used permanently or temporarily during construction until sufficient root penetration by vegetation is achieved. Scour protection in this context refers to protection against soil erosion caused by currents. Here, too, the geomaterial sheet can provide permanent or temporary soil protection.In particular, such scour protection can be achieved, for example, by flexible containers made of geomaterial sheeting filled with particle material such as sand or the like, which are placed on the ground layer to be stabilized.

[0031] The geomaterial sheet is used in such a way as to achieve targeted biodegradation. This targeted biodegradation can, on the one hand, consist of the geomaterial sheet itself becoming biodegradable at the installation site, unlike in previously known applications, and consequently dissolving as planned within a specific timeframe. Alternatively, the biodegradability can be designed so that the geomaterial sheet exhibits a higher biodegradability at a transport location than at the installation site. This ensures that if the geomaterial sheet is intentionally or unintentionally transported away from the installation site, it biodegrades more quickly at a transport location with different environmental conditions and therefore does not pose an environmental hazard.

[0032] Preferably, the geomaterial sheet is used to manufacture fillable containers, and these containers are then placed on the seabed when filled, thereby providing scour protection in areas with strong currents. This advanced training achieves a particularly effective scour protection.

[0033] The application can be further developed by installing the geomaterial membrane in shoreline or coastal protection at locations that are occasionally exposed to air or water, where the geomaterial membrane preferably has a lower density than water. Particularly in cases of occasional exposure to air or water, an unintentional release of the geomaterial membrane can occur during such stabilization measures, and its special biodegradability then proves advantageous.

[0034] Another aspect of the invention is a method for soil stabilization using a geomaterial sheet, comprising the steps of: a) determining a soil parameter value characterizing a soil property at an installation site, b) determining a degradation value characterizing a biological degradation rate, c) selecting a mixing ratio of a first and second structural material exhibiting different biodegradability based on the soil parameter value and the degradation value, d) combining the first and second structural materials to form a geomaterial sheet in the mixing ratio, e) providing the geomaterial sheet for installation at the installation site.

[0035] According to this aspect of the invention, soil stabilization at an installation site is achieved by providing a geomaterial sheet for installation in the soil layer at that location. For this, soil properties must be known. This means that at least one soil property that relevantly influences biodegradability must be determined or measured. For example, the soil moisture content, pH value, nutrient concentration, the presence of bacteria and fungi, and / or the soil temperature (averaged over a daily, weekly, monthly, or annual period) can be assumed or determined. Furthermore, the intensity of UV radiation at the installation site can be measured.

[0036] These site-specific parameters take into account the factors influencing the biological degradation process that prevail at the installation site. A characteristic value, for example as a dimensionless factor or as an empirical value from tables, can be determined from these parameters. For instance, the compostability or degradation under marine conditions, as previously explained according to ISO 16929, can serve as a standard reference value, and the degradation value can be defined in relation to this reference value. For example, a lower degradation rate due to soil properties can be characterized by a corresponding percentage below 100%, or a higher rate of biological degradation at the installation site can be characterized by a degradation value exceeding 100%.

[0037] Furthermore, a degradation value is determined, which defines within what period of time a certain degree of biological degradation of the geomaterial sheet or a component of the geomaterial sheet should be achieved.

[0038] Based on the soil parameter value and the degradation value, a mixing ratio of the first to the second structural material is selected. The first and second structural materials exhibit different biodegradability or degradation rates with respect to the soil parameter value. The mixing ratio determines the overall biodegradation rate of the geomaterial sheet, which is constructed from the first and second structural materials. This biodegradation rate depends on the soil parameter value assumed or measured at the installation site and should be selected to achieve the desired degradation value, which describes the rate of biodegradation of the geomaterial sheet.

[0039] After selecting the mixing ratio, the first and second structural materials are combined to form the geomaterial sheet. This combination can be achieved using nonwoven fabric, knitted fabric, woven fabric, or other methods, and is intended to create a mechanically resilient bond between the first and second fibrous materials. The resulting geomaterial sheet is therefore tailored for use and targeted biodegradation at the installation site, taking into account the prevailing conditions.

[0040] This solution ensures that the geomaterial membrane undergoes neither excessively rapid nor excessively slow biodegradation by incorporating soil parameters influencing biodegradation into its design. A specific degradation behavior, characterized by its degradation value, is achieved through a mixture of two fibrous materials.

[0041] The process can be further developed by using a soil parameter value that is, for example, the soil moisture content of the soil at the installation site (e.g., between 3 and 300 wt%), the soil pH value of the soil at the installation site (e.g., between 1 and 13), the enzyme concentration in the soil at the installation site, a temperature between 4°C and 50°C, or a soil parameter value derived from several of these soil parameters. These soil parameter values ​​determine significant influencing factors on the biodegradation rate of typical fibrous materials, such as viscose fibers like lyocell, and can therefore be used to design the geomaterial sheet with a biodegradability tailored to the specific installation site.

[0042] It is particularly preferred if the degradation value is a strength quotient, calculated as the ratio of a mechanical strength value to the installation time of the geomaterial sheet compared to the initial value; a permeability quotient, calculated as the ratio of a porosity value to the installation time of the geomaterial sheet compared to the initial value; or a degradation parameter derived from several of these degradation values. According to this embodiment, the degradation value is defined either as a strength quotient or as a permeability quotient, or as a degradation parameter calculated from the strength quotient and the permeability quotient. The strength quotient characterizes the decrease in the mechanical strength of the geomaterial sheet over a period of time the geomaterial sheet has been in the ground.This strength quotient is calculated as the ratio of the mechanical strength value at the time of installation, i.e., before any biological degradation has occurred, to the mechanical strength value after a predetermined residence time, which can be normalized to, for example, three or six months and characterizes the mechanical strength after biological degradation to a certain degree. Similarly, the permeability quotient is determined by comparing the initial porosity, i.e., at the time of installation, to the porosity after biological degradation over a predetermined period. This characterization of the degradation values ​​allows for the targeted determination and subsequent influence of desired properties through appropriate material selection. A strength quotient is on the order of 1.0 to 0 and is typically 0.25.The strength at a defined time point is reduced fourfold after biological degradation compared to the initial value. A typical permeability quotient is on the order of one to four orders of magnitude and ideally > 10, meaning that the permeability has increased tenfold at a defined time point after biological degradation compared to the initial value.

[0043] The previously described specific uses and methods for their application can be further developed by incorporating a polymer group into the geomaterial sheet that includes a molecule with an isotopic label, in particular a <13C or <18O isotopic label. According to this development, the geomaterial sheet is isotopically labeled and can therefore be unambiguously identified even in a later, potentially fragmented form. In this way, any environmental pollution that occurs can be unambiguously attributed to or ruled out, and the cause of such pollution can be quickly and reliably determined.

[0044] Furthermore, the process and application can be developed by incorporating a structural material into the geomaterial sheet, or by consisting of one or more structural materials that are metabolizable. Such metabolism by living organisms, such as mammals, fish, or microorganisms like microbes, leads to the reintegration of the geomaterial sheet into the biological cycle and thus to its environmentally harmless disposal. Metabolism can preferably occur at fragments such as shredded fiber remnants of the geomaterial sheet. Metabolism in this context refers, on the one hand, to the biologically safe compatibility of the geomaterial sheet with living organisms, and on the other hand, to the ability of the geomaterial sheet to be chemically altered and degraded through metabolic processes in the digestive tract of a living organism.

[0045] Furthermore, it is preferred if the geomaterial sheet is formed by a single- or multi-layer filter nonwoven fabric made of at least two different structural materials bonded together to form a nonwoven fabric, wherein A first structural material, under a predetermined intensity of an influencing parameter at an installation site, exhibits biodegradability to such an extent that, in a composting test with the following parameters: ∘ Samples with a length of 10 cm, a width of 10 cm and an original material thickness ∘ 50°C + / - 5°C ∘ thermophilic conditions according to ISO 16929, unless these are defined by specific intensities of specific influencing parameters at the installation site, ∘ sieving of the solids after six months in a sieve with a 2 mm mesh size (Mesh 8.75) where less than 80 wt.%, in particular less than 25 wt.% or less than 10 wt.% of the dry mass of the first structural material remains in the sieve after twelve weeks, or in a marine incubation test, with the following parameters: ∘ Samples with a length of 2 cm, a width of 2 cm and an original material thickness ∘ 30°C + / - 2°C ∘ Aerobic conditions in seawater with a salinity of 3.5 wt.-% + / - 1 wt.%, unless these are defined by specific intensities of specific influencing parameters at the installation site, ∘ Sieving of the solids after 4, 8 and 12 weeks in a sieve with 2mm mesh size (Mesh 8.75) at sieving after 12 weeks less than 80 wt.%, in particular less than 25 wt.% or less than 10 wt.% of the dry mass of the first structural material at sieving after twelve weeks remains in the sieve.wherein the predetermined intensity of the influence parameter is selected from: an intensity of radiation exposure, an electromagnetic radiation, an altitude, a temperature, a concentration of a substance that reacts chemically and / or biochemically with the geomaterial web, a concentration of bacteria, a concentration of fungi, and a second structural material is combined with the first structural material to form the filter fleece, wherein the second structural material, under the same predetermined intensity of the influence parameter at the same installation location, exhibits a lower biodegradability to such an extent that, within six months under the same conditions, a larger wt.% proportion of the dry mass of the second structural material remains in the sieve after six months or twelve weeks when sieved through a 2mm sieve than that of the first structural material.According to this training method, the geomaterial sheet is designed as a nonwoven fabric consisting of two different structural materials that exhibit different rates of biodegradation under the given, predetermined parameters. This allows the nonwoven fabric to undergo, on the one hand, targeted mechanical weakening of its structure through the biodegradation process, and on the other hand, geometric changes such as pore formation, perforation, or similar features, in order to, for example, promote root penetration.

[0046] Compared to the first structural material, the second structural material exhibits a second biodegradability that is different, and in particular lower, than that of the first structural material. This means that after six months or twelve weeks, a second weight percentage of the second structural material remains in the 2mm sieve, which is different, and in particular higher, than that of the first structural material. Therefore, if, for example, in the composting test 70% by weight of the first structural material degrades into particles <2mm within six months, a weight percentage of 60% of the second structural material can degrade into particles <2mm within the same period under the same conditions.

[0047] The invention therefore provides a geomaterial sheet which undergoes a defined conversion to carbon dioxide through biodegradation, wherein one of the two structural materials encompassed in the geomaterial sheet or from which the geomaterial sheet is constructed degrades more rapidly than the other. This allows both the geometric and mechanical properties of the geomaterial sheet to be selectively influenced by biodegradation.For example, the faster degradation of the first structural material in the geomaterial layer can create openings or pores that are advantageous for root penetration. This is because the increased space requirement of the plant roots, which arises with increasing root penetration, is provided by the biological degradation of the first structural material, while at the same time the necessary mechanical stabilization is maintained by the second structural material. Furthermore, in woven, knitted, nonwoven, or composite materials made of the first and second structural materials, for example, a mechanical property may be reduced more significantly in a first direction, where the first structural material is predominantly located in the geomaterial layer, than a mechanical property in a different second direction, where the second structural material is predominantly located in the geomaterial layer.For example, in slope stabilization, stability perpendicular to the slope direction can be reduced more rapidly than stability in the slope direction. This allows for the desired slight movement of the geomaterial layer to promote plant growth, while simultaneously preventing slippage in the slope direction. The two structural materials can differ, for instance, in that the first material is made of a different material than the second, or contains a different material than the second. Alternatively, the material of the first and second structural materials may be identical, but the material of the first has undergone a different treatment than the material of the second. Preferably, the first and second structural materials do not differ with respect to specific properties such as fiber thickness and / or fiber length.

[0048] In principle, in addition to influencing the geometric and mechanical properties through the specific arrangement of the first and second structural materials within the geomaterial sheet, the mechanical properties can also be influenced overall over the degradation period of the geomaterial sheet by selecting and determining the proportions of these materials. This advantageously allows the rate of biological degradation and the reduction of mechanical / geometric properties to be adapted to local conditions at the installation site. While standardized biodegradability is determined under standardized conditions, different influencing parameters for biodegradability may prevail at the installation site. For example, an increased oxygen content can lead to faster biological degradation, and conversely, a reduced oxygen content to slower biological degradation.Furthermore, influencing factors such as increased UV radiation, a high or low pH value, an increased nutrient supply, an increased proportion of bacteria, an increased proportion of fungi, and other factors can affect the rate of biological degradation. By being able to change the mixing ratio of the first and second structural materials in the geomaterial membrane according to the invention, it is therefore possible, for example, to increase the proportion of the second structural material if local influencing factors at the installation site are expected to lead to an increased rate of biological degradation, or conversely, if influencing factors at the installation site are expected to reduce the rate of biological degradation, this can be countered by increasing the proportion of the first structural material, in order to obtain a geomaterial membrane adapted to the local conditions with a tailored rate of biological degradation.

[0049] Preferably, the first structural material has a higher biodegradability than the second. According to this embodiment, the second structural material has a lower biodegradability than the first; that is, the second structural material degrades more slowly. For example, the first structural material can have a biodegradability such that after six months or twelve weeks, at least 90% by weight of the first structural material has degraded to particles smaller than 2 mm, whereas for the second structural material, only 80% by weight or less has degraded. This means that less than 10% by weight of the first material remains in the 2 mm sieve, whereas for the second material, more than 20% by weight remains. Preferably, the second structural material has a biodegradability such that after six months, less than 50% has degraded to particles smaller than 2 mm.

[0050] It is even more preferred if the first structural material in the geomaterial sheet is arranged such that, after partial or complete biological degradation of the first structural material in the geomaterial sheet, openings penetrating the geomaterial sheet are formed. According to this embodiment, the geometric appearance of the geomaterial sheet changes due to the faster degradation of the first structural material, creating openings penetrating the geomaterial sheet. The first structural material is therefore arranged in the geomaterial sheet such that, in its initial state, it closes these openings and, through its degradation, exposes or creates them. The geomaterial sheet is thereby perforated.It becomes more perforated and consequently adapts to a root penetration process, which, with increasing root penetration, necessitates both greater permeability of the geomaterial membrane and lower mechanical strength. The desired effect of creating openings through the degradation of the first structural material can be achieved, for example, by combining the first and second structural materials into a nonwoven fabric.

[0051] It is further preferred that the first structural material partially or completely penetrates the second structural material. Such penetration can, on the one hand, achieve a specific, directed or undirected mechanical destabilization of the geomaterial layer through the biological degradation of the first structural material. On the other hand, specific directed or undirected channels and openings can be created in the second structural material through the biological degradation of the first structural material, extending along the point of penetration.

[0052] It is even more preferred that the first and second structural materials are bonded together as a layered composite, that the second structural material has a multitude of secondary perforations and the first structural material has no perforations, or that it has a multitude of primary perforations that are smaller than the secondary perforations. This configuration ensures that the faster degradation of the first structural material can result in larger openings penetrating the entire geomaterial sheet.

[0053] Further development involves enhancing the use of the geomaterial membrane by incorporating it into structures designed to influence airflow. This integration specifically aims to locally reduce airflow velocity, thereby facilitating the deposition of particles that, at higher air speeds, would otherwise be suspended, bounce, or roll. The geomaterial membrane, its application, and the method thus serve to deposit minerals, particularly sand, on coastal areas at risk of sand erosion. The reduction in air velocity leads to sand deposition, preferably downwind of the structures. The structure is then partially or completely covered with sand.The geomaterial sheet according to the invention thus becomes part of the sand deposit and can be dismantled at the installation or disposal site if the structure is exposed again due to a change in erosion conditions, insofar as the structure can be dismantled within the sand deposit according to the invention or if the structure is dismantled at the installation or disposal site according to the invention.

[0054] Preferred embodiments are explained with reference to the figures. They show: Fig. 1 a schematic representation of a use of the geomaterial sheet according to the invention in three different arrangements for coastal protection, Fig. 2a, a use of the geomaterial sheet according to the invention for slope stabilization at two different root penetration times, Fig. 3 a schematic representation of a first embodiment of the geomaterial sheet, Fig. 4 a schematic representation of a second embodiment of the geomaterial sheet, Fig. 5 a schematic representation of a third embodiment of the geomaterial sheet, Fig. 6 a schematic representation of a fourth embodiment of the geomaterial sheet.

[0055] The geomaterial sheet used according to the invention can, in principle, be installed in three different installation situations with respect to water contact in the shoreline area. Starting from a natural shoreline area 2, adjacent to the waterline or, in the case of tidal waters, the average water level, and which may be protected against flooding by an artificial dike 3, a geomaterial sheet can initially be installed in position A to stabilize the underwater terrain profile of the natural seabed, where stabilization of the soil by vegetation is only partially possible. In this installation position A, the geomaterial sheet is generally submerged and may, in exceptional cases, be exposed at low tide or during heavy waves.

[0056] In a second installation position B, the geomaterial membrane is installed on the water side to reinforce the natural riverbank and / or the artificial dike slope. In this installation position, the geomaterial membrane stabilizes the usually dry portion of the natural bank and, if applicable, the artificial dike slope. It is therefore generally dry, but can be submerged during floods or heavy waves.

[0057] In a third installation position, C, the geomaterial membrane is deployed in an area, such as the back side of the dike, where it is not exposed to the water itself and can only be subjected to stress in special situations such as overflow. In this installation position, the geomaterial membrane is therefore always dry and, as in every installation position, is only exposed to moisture from rainfall.

[0058] Each of the three installation positions requires differently tailored behavior of the geomaterial sheets to achieve ecologically favorable performance. For example, in installation position A, stability of the geomaterial sheet in an aqueous environment is required. However, if parts of this geomaterial sheet detach due to abrasive events and are therefore no longer in the location required for its function, the degradation of these detached geomaterial sheet components is desirable. According to the invention, this can be achieved, for example, by constructing the geomaterial sheet from a material that degrades rapidly under the influence of UV radiation. This ensures that detached parts of the geomaterial sheet that float to the surface or are washed ashore undergo rapid degradation, whereas at the installation site, when no UV radiation reaches the geomaterial sheet, its mechanical stability is maintained.Instead of specifying the geomaterial membrane for UV radiation, it is also possible, for example, to specify its biodegradability depending on the oxygen content of the water and / or the bacterial and / or fungal concentrations in certain applications. This is particularly suitable when geomaterial membranes are used at great depths in the ocean, where low concentrations of the aforementioned influencing parameters prevail. In this case, the geomaterial membrane material can be designed to be mechanically stable in the planned installation situation and the surrounding water, and to biodegrade as soon as the concentration of influencing parameters in the surrounding water or at the deployment site increases.

[0059] The installation situation according to C is relevant to the invention, for example, with regard to root penetration and the adaptation of the geomaterial sheet to root penetration processes. Fig. 2a und b The figures show two successive root penetration situations in which a geomaterial sheet 10 is installed at a specific depth to stabilize a soil layer 20. How can one learn from Fig. 2a The geomaterial layer 10, observed in an early stage shortly after the planting of soil-stabilizing plants, exhibits a high density with only small openings, thereby providing high mechanical stabilization of the soil. The planted plants can penetrate the geomaterial layer with small root shoots and are thus not hindered in their growth. An effective mechanical bond between the geomaterial layer and the plants is already achieved at this early stage.

[0060] Fig. 2b The image shows the same installation situation after several weeks of plant growth. The geomaterial membrane has partially decomposed mechanically through biological degradation. It exhibits larger openings and reduced mechanical stability. The larger openings do not impede the growing plants' root development and the increase in root diameter, allowing them to fulfill their mechanical stabilizing function. Therefore, the geomaterial membrane according to the invention achieves a continuous transfer of the soil's mechanical stability from the geomaterial membrane to the plants, while simultaneously maintaining a good mechanical connection between the plants and the geomaterial membrane. Furthermore, the geomaterial membrane continues to exhibit mechanical properties, possibly varying in direction, and performs functions for soil stabilization.

[0061] Fig. 3 bis 6 Figure 1 shows exemplary embodiments of a geomaterial sheet. In principle, the geomaterial sheets according to the invention can be provided in different widths and lengths. Typical widths are greater than 1 m, 1.5 m, or 2 m and less than 4 m, 5 m, or 6 m, and typical lengths are longer than 2 m, 5 m, 10 m, or 50 m. The geomaterial sheet is preferably transportable in a rolled-up state and is unrolled during installation. The thickness of the geomaterial sheet can be greater than 1 mm; thicknesses greater than 5 mm, 10 mm, or 20 mm are preferred. The geomaterial sheet can have a basis weight greater than 150 g / m², greater than 300 g / m², or less than 1500 g / m², less than 2000 g / m², or less than 2500 g / m².

[0062] Fig. 3 Figure 1 shows a first embodiment with a top layer 110, a support layer 120 and an intermediate layer 130 arranged between the top layer 110 and the support layer 120. The top and support layers 110 and 120 can be made of different or identical materials, and the intermediate layer 130 can be made of the same material as the top and support layers or of a different material.

[0063] The cover layer and the support layer are connected by means of needling, stitching, or interlocking. For this purpose, several needling points 140a, b, c are inserted into the geomaterial sheet, connecting the cover layer to the support layer through the intermediate layer 130. In this design of a geomaterial sheet, the cover layer can, for example, consist of a material that biodegrades more rapidly than the support layer 120. As a result, after partial or complete biodegradation of the needling, stitching, or interlocking elements of the geomaterial sheet, channels are formed that extend from the top to the bottom of the geomaterial sheet and provide, for example, space for root penetration or drainage effects.

[0064] Fig. 4 Figure 2 shows a second embodiment of a geomaterial sheet comprising an upper grid layer 210 and an underlying nonwoven layer 220. The grid layer 210 is formed by a crosswise lattice of strong individual fibers or rods, creating grid openings of a specific size, for example, 10 x 10 mm to 40 x 40 mm. The nonwoven layer is formed from dense, randomly oriented fibers of a different material than the grid layer 210. This nonwoven layer effectively closes the openings of the grid layer 210, resulting in a geomaterial sheet that is impermeable to larger particles but permeable to liquids and gases. The nonwoven layer 220 is made of a material such as lyocell and biodegrades more rapidly than the grid layer 210.This reduces the mechanical strength of the geomaterial sheet within the short biological degradation time of the nonwoven layer 220, and after the degradation of the nonwoven layer 220, the geomaterial sheet is reduced to the remaining grid layer 210 with the openings formed therein, which in turn provide sufficient space for favorable root penetration.

[0065] Fig. 5 Figure 3 shows a third embodiment, which is basically designed as a single-layer geomaterial sheet. In the geomaterial sheet, fibers 310 of a first material are arranged in a first direction, and fibers 320 are arranged in a second direction, transverse to the first direction, thereby forming fiber layers. The fibers 310 and 320 can be connected to each other, for example, by welding, bonding, looping, needling, weaving, or knitting techniques, and / or by means of a cover and support layer above and below the fibers 310 and 320. The fibers 310 are made of a different material than the fibers 320, and the material from which the fibers 320 are formed biodegrades more rapidly than the material from which the fibers 310 are formed.Due to this biological degradation behavior of the geomaterial sheet, the geomaterial sheet initially exhibits load-bearing capacity in the longitudinal and transverse directions, corresponding to the orientation of the fibers 310, 320. With increasing biological degradation of the fibers 320, the strength and load-bearing capacity in the longitudinal direction along the orientation of the fibers 320 decreases, resulting in an anisotropic mechanical load behavior of the geomaterial sheet.

[0066] Fig. 6A fourth embodiment is shown in which two different materials are processed into a nonwoven layer, which constitutes a geomaterial sheet or can constitute a layer of a geomaterial sheet. The two different materials 410, 420 are processed into a nonwoven in an unoriented manner as short or long fibers or continuous fibers and bonded together. Material 420 biodegrades faster than material 410, whereby the density of the geomaterial sheet decreases with increasing biodegradation in the installation situation, and the geomaterial sheet becomes more permeable and / or its mechanical properties change.

[0067] It is understood that the four embodiments can also be combined by producing multilayer geomaterial sheets that exhibit combined properties of these embodiments. Furthermore, it is understood that the four embodiments can also be combined in such a way that their properties are united in a single layer of a geomaterial sheet, for example, by forming the grid structure 210 of the second embodiment with the anisotropically biodegradable fibers 310, 320 of the third embodiment.

[0068] The biodegradation behavior can, in principle, be adjusted at the installation site and adapted to the prevailing conditions there. Thus, in all embodiments, the proportion of one material relative to the proportion of the other material can be increased or decreased to achieve the desired biodegradation behavior. Furthermore, the biodegradation properties can be influenced or even triggered by external factors such as UV radiation, oxygen content, and / or the concentration of bacteria, fungi, or chemical influences in the environment. This results in specific biodegradation behavior of the geomaterial sheets when they are moved from one location to another where these specific environmental conditions change.

Claims

1. Method for location-dependent soil stabilization by means of a geomaterial web, comprising the steps: Configuring a product for influencing parameters determining the durability of the geomaterial at the installation site, whereby the influencing parameters are selected from: - an intensity of a radiation effect of an electromagnetic radiation, - a height of a temperature, - a concentration of a substance that reacts chemically and / or biochemically with the geomaterial web, - a concentration of a concentration of bacteria, - a concentration of fungi, determining one or more of these influencing parameters at a transfer site at a distance from the installation site, - installing the geomaterial web at the installation site, wherein the geomaterial web comprises a structural material which ∘ shows biodegradability under the intensity of the influencing parameter at the transfer site to the extent that a transfer site residual portion remains in a sieve with a mesh size of 2 mm within six months if the material or its components are sieved, ∘ wherein the transfer site residual portion is less than 80 wt.%, preferably less than 25 wt.% or less than 10 wt.% of the material, ∘ exhibits biodegradability at the installation site under the intensity of the influencing parameter to the extent that an installation site residual portion of the material remains in a sieve with a mesh size of 2 mm within six months if the material or its components are sieved, ∘ where the installation site residual portion is greater than the transfer site residual portion. wherein preferably the installation site has an environment with a lower temperature, radiation, oxygen, bacteria and / or fungi concentration than the place of transfer.

2. Method according to claim 1, characterized in that the installation site is on the seabed and the geomaterial web floats or is moved in seawater as a result of a current and / or density differences.

3. The method according to any one of claims 1-2, characterized in that the structural material is a viscose-based material, in particular lyocell.

4. Method according to any of the preceding claims 1-3, characterized in that - the geomaterial web has a polymer group comprising a molecule provided with an isotopic label, in particular a 13C or 18O isotopic label, and / or - the geomaterial web comprises a structural material or consists of one or more structural materials that are metabolizable.

5. Method according to any of the preceding claims 1-4, characterized in that the geomaterial web is formed by a single-layer or multi-layer filter nonwoven which is produced from at least two different structural materials which are bonded together to form a nonwoven fabric, wherein - a first structural material exhibits biodegradability under a predetermined intensity of an influencing parameter at an installation site to the extent that a percentage by weight of more than 50%, in particular more than 75%, of the structural material is converted into carbon dioxide in the aqueous medium within six months, where the predetermined intensity of the influencing parameter is selected from: - Intensity of a radiation effect of electromagnetic radiation, - Height of a temperature, - Concentration of a substance that reacts chemically and / or biochemically with the geomaterial web, - Concentration of a concentration of bacteria, - Concentration of fungi, - and a second structural material is bonded to the first structural material to form the nonwoven filter fabric, the second structural material exhibiting biodegradability under the same predetermined intensity of the influencing parameter at the same installation site to the extent that - in a composting test with the following parameters: ∘ Samples with a length of 10 cm, a width of 10 cm and an original material thickness ∘ 50°C + / - 5°C ∘ thermophilic conditions according to ISO 16929, ∘ Sieving out the solids after six months in a sieve with an ash width of 2 mm (mesh 8.75) - less than 50 % by dry weight of the starting material remains in the sieve during sieving, or - in a marine incubation test, with the following parameters: ∘ Samples with a length of 2 cm, a width of 2 cm and an original material thickness ∘ 30°C + / - 2°C ∘ aerobic conditions in seawater with a salt content of 3.5 wt.% + / - 1 wt.%, ∘ Sieving out the solids after 4, 8 and 12 weeks in a sieve with a mesh size of 2 mm (mesh 8.75) less than 20 % by dry weight of the starting material remains in the sieve after 12 weeks.

6. Method according to any one of the preceding claims 1-5, characterized in that the geomaterial web is installed as an element in structures which serve to influence air flows in such a way that, in particular, the speed of the air flow is reduced locally for the purpose of depositing particles which are transported suspended in the air, bouncing or rolling when the air speed is not reduced.

7. Use of a geomaterial web comprising a structural material which - exhibits biodegradability under a first intensity of an influencing parameter at an installation site to the extent that - In a composting test with the following parameters: ∘ Samples with a length of 10 cm, a width of 10 cm and an original material thickness ∘ 50°C + / - 5°C ∘ thermophilic conditions according to ISO 16929, unless these are defined by specific intensities of specific influencing parameters at the installation site, ∘ Sieving out the solids after six months in a sieve with a mesh size of 2 mm (mesh 8.75) - more than 80 % by dry weight, 25 % by dry weight, 10 % by dry weight of the starting material remains in the sieve during sieving, or that - in a marine incubation test, with the following parameters: ∘ Samples with a length of 2 cm, a width of 2 cm and an original material thickness ∘ 30°C + / - 2°C ∘ Aerobic conditions in seawater with a salt content of 3.5 wt.% + / - 1 wt.%, unless these are defined by specific intensities of specific influencing parameters at the installation site, ∘ Sieving out the solids after 4, 8 and 12 weeks in a sieve with a mesh size of 2 mm (mesh 8.75) - more than 80 % by dry weight, more than 25 % by dry weight, 10 % by dry weight of the starting material remains in the sieve after 12 weeks, and - under a second intensity of the influencing parameter at a transfer site, exhibits biodegradability to the extent that within six months in the composting test or twelve weeks in the marine incubation test less than 80 % by weight, in particular less than 25 % by weight or less than 10 % by weight of the dry mass of the first structural material remains in the sieve after sieving through a sieve with a mesh size of 2 mm, where the intensity of the influencing parameter is selected from: - Intensity of a radiation effect of electromagnetic radiation, - Height of a temperature, - Concentration of a substance that reacts chemically and / or biochemically with the geomaterial web, - Concentration of a concentration of bacteria, - Concentration of fungi, - Expected mechanical stresses. in such a way that the geomaterial web is installed at the installation site at one time and transferred to the transfer site at a later time following the installation time.

8. Use of a geomaterial web according to claim 7 for installation in a soil layer for the purpose of soil stabilization.

9. Use according to any of the preceding claims 7-8, characterized in that - the geomaterial web has a polymer group comprising a molecule provided with an isotopic label, in particular a 13C or 18O isotopic label, and / or - the geomaterial web comprises a structural material or consists of one or more structural materials that are metabolizable.

10. Use according to any of the preceding claims 7-9, characterized in that the geomaterial web is formed by a single-layer or multi-layer filter nonwoven which is produced from at least two different structural materials which are bonded together to form a nonwoven, wherein - a first structural material exhibits biodegradability under a predetermined intensity of an influencing parameter at an installation site to the extent that a percentage by weight of more than 50%, in particular more than 75%, of the structural material is converted into carbon dioxide in the aqueous medium within six months, where the predetermined intensity of the influencing parameter is selected from: - Intensity of a radiation effect of electromagnetic radiation, - Height of a temperature, - Concentration of a substance that reacts chemically and / or biochemically with the geomaterial web, - Concentration of a concentration of bacteria, - Concentration of fungi, - and a second structural material is bonded to the first structural material to form the nonwoven filter fabric, the second structural material exhibiting biodegradability under the same predetermined intensity of the influencing parameter at the same installation site to the extent that - In a composting test with the following parameters: ∘ Samples with a length of 10 cm, a width of 10 cm and an original material thickness ∘ 50°C + / - 5°C ∘ thermophilic conditions according to ISO 16929, ∘ Sieving out the solids after six months in a sieve with an ash width of 2 mm (mesh 8.75) - less than 50 % by dry weight of the starting material remains in the sieve during sieving, or - in a marine incubation test, with the following parameters: ∘ Samples with a length of 2cm, a width of 2cm and an original material thickness ∘ 30°C + / - 2°C ∘ Aerobic conditions in seawater with a salt content of 3.5 wt.% + / - 1 wt.% ∘ Sieving out the solids after 4, 8 and 12 weeks in a sieve with a mesh size of 2 mm (mesh 8.75) less than 20 % by dry weight of the starting material remains in the sieve after 12 weeks.

11. Use according to any of the preceding claims 7-10, characterized in that the geomaterial web is installed as an element in structures which serve to influence air flows in such a way that, in particular, the speed of the air flow is reduced locally for the purpose of depositing particles which are transported suspended in the air, bounce or roll when the air speed is not reduced.