Building Industry

The role of pre-seeds and geomats in the process of bank protection and water flow management What are hydraulic systems? When we say “hydraulic systems” we are referring to all those preventive works in the field of hydraulic engineering that aim to protect the land from erosion and improve navigation in watercourses by controlling and managing the flow of water in natural or artificial environments. In addition, they play an important role in the renaturalisation of riverbanks and the creation of ecological corridors, which are useful for the biodiversity of nature. The mission of Virens is to restore to nature its primary functions and distinctive characteristics, an element of salvation, not only for nature itself, but also for mankind. The objective is to reconcile the performance of our products with the preservation of the environment and the diversity of the territories, thanks to constant innovation and territorial studies, using analysis, tests and research in collaboration with organisations and professionals in the sector. Avoid erosive phenomena, and allow the greatest amount of water to be absorbed Take, for example, the Po Valley, a large alluvial area subject to intense water flows, characterised by soil that can be easily eroded by heavy rainfall and flooding rivers. In this area, hydraulic systems such as dams, rolling basins and drainage canals play a key role, as they control the flow of water by reducing it during floods and prevent soil erosion. These works also make it possible to store water in times of abundance and release it gradually when needed, facilitating absorption and reducing the risk of flooding in populated areas. In the past, it was quite common to cement the banks to obviate the problem of soil erosion, but nowadays, there is a growing realisation that this technique actually increases the speed of water flows and the danger in times of flood. It is important, therefore, to implement environmental and planning policies aimed at prevention and damage limitation in those areas at risk, given the danger and increased frequency with which we are witnessing major weather and climate events. Renaturalising banks, reducing flow velocities, contributing to ecological corridors and biodiversity The renaturalisation of the banks is an essential phenomenon as it favours the conservation of river ecosystems, providing habitats for plant and animal species, improving water quality and contributing to biodiversity through the creation of ecological corridors. But what are ecological corridors? Also known as ecological networks, they are strips of natural habitat that connect several distinct ecosystems. These areas allow organisms to move from one habitat to another, facilitating the migration and dispersal of species. These green corridors can be rivers, forests, meadows or strips of vegetation along roads. The fundamental role played by these green corridors is the conservation of biodiversity: by allowing species to move between different areas, they give them access to new food resources and breeding grounds. In addition, they can provide an escape route for species that, as a result of climate change, need to move to more favourable environments. Creating these spaces results in an improved quality of life, not only for nature itself, but also for man. Virens solutions We have seen how, in an area characterised by erosive phenomena, flooding and intense water flows, intervening with hydraulic engineering works is essential to preventing environmental damage, protecting agricultural land and creating an environment favourable to biodiversity. Virens has always been actively involved in the design and construction of all things related to the banks of these areas, which are subject to periodic flooding, since they must also be protected from occasional erosion due to both rainfall and water flows. Virens intervenes mainly in the most exposed situations such as banks, i.e. places where water impacts the soil, and the ground receives more stress, thus requiring more protection. In these cases it is not sufficient to rely on vegetation, as the power of precipitation is too strong for plant roots alone to be able to hold it back. Our products are ideal for grassing the bank more securely. The use of Viresco® in the second embankment level and Virmat or RecsViresco in the first embankment level, allows for double and greater protection. Another product we offer is Viresco Sator with mixtures of melliferous plants, our seed-rich pre-seeded product that attracts pollinating insects, which are crucial in helping to protect our planet.

What are Geomats? Three-dimensional geomats were developed in the 1960s and consist of synthetic filaments woven together and fused at the contact points with a thickness of approx. 2 cm, making them a very flexible, lightweight and easy-to-use material. They are used to control the erosion of slope surfaces caused mainly by atmospheric phenomena, such as water runoff and wind, and perform this function from the moment they are laid, thanks to the strength of the materials they are made of. They are highly durable and fall into the category of Turf/Earth Reinforcement Mats (TRMs). The role of geomats Three-dimensional geomats consist of an open structure with a high void ratio that allows vegetation to grow and establish itself without creating any obstacles. It is important to remember that a well-vegetated geomembrane slows down the flow velocity of water, but also of wind, and is capable of doubling resistance to water flows. For this reason, they are mainly used on earthen slopes, and prior to installation, adequate preparation of the intervention site is required by means of reprofiling the slopes and establishing a slope profile that is compatible with the geological characteristics of the site and the requirements of stability, safety and landscaping. Application of geomats  The geomats are usually applied after digging anchor trenches approx. 50 cm beyond the top of the slope, which can differ depending on the type of soil, the slope inclination, or the presence of watercourse banks, etc. Subsequently, the trenches, once the geomat has been laid and anchored, must be filled with soil and compacted. The geomats are then unrolled, taking care to maintain contact with the ground, anchoring and overlapping the rolls according to possible water flows. Geomats can be applied to: slopes of significant height very steep slopes watercourses banks and beds loose slopes poor soils poorly irrigated escarpments. Geomats are easy to lay and do not require specialised labour or technical equipment, and they do not suffer from corrosion the way metal products do. Virmat pre-seeded geomats They Virmat geomats are an evolution of traditional geomats: combined with pre-seeded biotextile Viresco® Sator fabric assembled in the lower part of the product, they are designed to offer the best performance on the market. This combination produces an effective protective action and an excellent vegetative result by permanently fixing seeds and fertilisers. The ability of pre-seeded three-dimensional geomats to retain a layer of vegetable soil at the top of the mat provides moisture and thermal protection to the seed contained in the underlying bio-textile, which in turn, prevents the loss of fine soil in all weather conditions and ensures perfect cover for vegetation.  Thus, on the one hand it provides robust slope protection from the outset, and on the other hand, it provides rapid grassing and reinforced anchoring of the roots to the soil and the three-dimensional structure, which is rendered invisible by the vegetation. The result is a single vigorous block that is resistant to erosive forces. In the case of traditional unseeded three-dimensional geomats, it is necessary to spread the seed underneath, before laying, or on top, after laying. With Virmat on the other hand, erosion control and seeding are achieved in one single solution, with lower costs and increased effectiveness.

Reinforced soil is a technology that is revolutionising civil engineering and infrastructure construction. This innovative practice combines the use of geosynthetic materials with natural soils or granular materials to improve performance and stability. What are reinforced soils? Reinforced soils are engineered structures consisting of a combination of geosynthetic material, such as geotextiles or geogrids, and natural soil or granular material. These materials are used to improve the load, drainage and stability characteristics of the soil. Reinforced soil is often used in situations where unstable or poor-quality soil requires reinforcement. They originate from construction intuitions dating back to antiquity, into which materials such as ropes, cloths or strong cloths were inserted to increase their resistance, especially to traction. This practice stems from the recognition of the fact that some materials, such as the concrete used today, exhibit high compressive strength but lower tensile strength. For this reason, in the 1960s in France, the idea was developed to insert metal elements into the earth mass in order to increase strength (mechanically stabilized earth). Thus, the elements that characterise modern reinforced soils are the reinforcing elements represented by the geogrids and the covering of the surface by means of bio-mats and bio-textiles, applied to retain the small particles of soil that may become detached due to physical and atmospheric agents, with the task, in our case of the pre-seeded products, of greening the façade with a better environmental integration and a better aesthetic effect. The Viresco® Satorpre-seeded biotextile for example, is used for its ability to deal with critical situations while also enhancing them from an aesthetic point of view. The use of Viresco® Sator in reinforced soil Once the reinforced soil has been designed taking into account all the morphological, geological, hydrogeological and geotechnical variables of the situation in which it is to be worked on, we proceed to its construction by first creating the work plan. Subsequently, metal formwork of an established height and inclination is put into position. The geogrid is laid on top of these, fixing it at the bottom and at adjacent points between them. Practicality and ease of handling also make the Viresco® Sator biotextile advantageous during the construction phase, and once the arrangement of all other materials has been completed, the pre-seeded biotextile is laid in such a way as to create a 10-15 cm flap at the bottom and at the top of the formwork. The metal stiffening rods of the formwork are then installed by piercing the biotextile according to the planned inclination. Before backfilling, at least 20 cm of fertile plant soil is laid close to the structure that is in contact with the bio-textile fabric, compacting it slightly. The remaining backfill soil can be recovered at the site or retrieved from external sources. The backfill soil must therefore be placed in layers and compacted in a manner appropriate to its constituent characteristics and the degree of humidity in which it is to be used, in order to avoid significant settlements at a later date after construction. In the case of reinforced soil over several levels, the operations described above are repeated until the top level of the work is reached. Once the construction phases have been completed, and depending on temperature and sunshine, it is recommended to water the turf frequently until it is fully settled. Viresco® Sator effectively retains the finer parts of the soil and ensures its greening while achieving truly aesthetic results. Advantages of using Viresco® Sator The possibility of customising the essences contained in the pre-seeded biotextile allows for the best vegetative performance in the most diverse environmental and climatic conditions. Furthermore, variations are also possible according to the customer's needs, up to and including floral arrangements and colour requirements. Given the difficulty in greening these surfaces (due to slope, substrate quality, water shortage, etc.), having such a refined and perfected technical solution such as Viresco® Sator is a non-negligible and much appreciated advantage. Reinforced soils, once they have been planted, have a well-ordered appearance, with healthy plants that fully fulfil their function from a physical, aesthetic and environmental point of view in terms of mitigating dust, noise and providing all the environmental health benefits that greenery can provide. Applied in all latitudes and geographical contexts, Viresco® now boasts 30 years of experience in geotechnics and reinforced soils, establishing itself as the best and most environmentally friendly solution for greening these types of soils.