System for reinforced soil retaining structures
T-System is the system from TeMa Geo Solutions that includes various components for strengthening, surface erosion control, drainage and retaining used in the construction of reinforced soil retaining structures: innovation that we’ve been exploring here at TeMa since our inception 30 years ago, and that is now one of our hallmarks. Let’s take a more detailed look below.
Components for strengthening
Designed for strengthening, the knitted X-Grid PET C geogrids are made from high-strength polyester yarn, with a protective polymer coating. They deliver tensile strength in the 20 kN/m to 800 kN/m range.
Components for erosion control
They protect the face of the structure from erosive agents, like wind and driving rain, until the vegetation has had time to establish. TeMa Geo Solutions offers natural solutions made from cellulose fibres, like Ecovermat, or jute fibres, like Ecovernet, as well as synthetic solutions made from monofilaments (K-Mat F), polypropylene (K-Mat FA) or fibreglass (K-Mat FG Green).
Components for drainage
Drainage geocomposites like Q-Drain are used to address the problem of water seeping into the backfill.
Components for retaining
We have a line of facings made from electrically welded wire mesh — with inclinations ranging from 65° to 80° — to ensure the exposed face is straight.
Practical tips
On site
System components must be stored well away from machinery, and suitably protected from dust or residues from work on site.
To avoid excessive overlaps and waste, the X-Grid geogrids must be cut to size using a suitable metal stand with metal trestles supporting a circular rod to be inserted inside the roll.
Erosion control components — whether biodegradable or synthetic — must be stored in a dry place and not in direct contact with the natural ground, so as to avoid laying problems later on.
Metal formwork must be stored well away from areas where machinery is operating, and carried in only when it is time to install.
During assembly, it is best to apply U-shaped strips of rubber or metal so that the geogrids can be wrapped correctly over the formwork without getting caught on the top of the bars. (see photo)
Special instructions
We advise against backfilling with silty and clayey material; at the very least, only use this kind of material after mixing it with aggregate.
The full range of system components comes with instructions on the relevant procedures to be followed. Contact us, we’ll be happy to provide case studies and full information.
- Published in Erosion mats, GEO, Geogrids, news, Reinforced earth structures, Reinforced earth structures - Drainage, Reinforced earth structures - Erosion control
Safety first: and that applies to landfills, too
TeMa Geo Solutions’ thirty years of experience extends to the field of controlled landfills and contaminated sites, with products specially designed for each function to ensure the site is safe, and with investment-conscious solutions, as well as a focus on ensuring peak performance.
Safe landfills legislation
In Italy, regulation around the controlled disposal of waste dates back as far as 1982, later supplemented by the European directive and updated in 2020 by Italian legislation (D.Lgs no.121).
This legislation covers all aspects of the disposal cycle, from landfill classification to the type of waste, as well as criteria for the construction and operation of the facilities, with a strong environmental focus. In this regard, TeMa has come up with built-up systems and materials that fulfil the required functions and comply with the relevant legislation.
The main functions to make safe a controlled landfill
Making safe a landfill facility entails fulfilling a number of functions:
Barrier
Walls and floor must be isolated to protect groundwater and soil from leachate and biogases resulting from decomposition processes. To ensure sufficient watertightness, legislation requires the use of at least 0.5 m of clay or, drawing on the principle of hydraulic equivalence, synthetic products: sodium bentonite composites like Barrier Bento — which contains up to 5 kg of bentonite/sqm sandwiched between two geotextiles — provide an impermeable layer, acting as a barrier between soil and waste.
Reinforcement
One of the major issues to be addressed when designing landfills, especially the capping system, is stability, which can be achieved by leveraging the compressive strength of the soil combined with the tensile strength of geosynthetics. Reinforcement solutions provided by TeMa range from PET-series geogrids to geomats laminated with geogrids.
Drainage
For liquid and gas capture, legislation calls for the use of 50 cm of aggregate, which nonetheless can come with its own stability issues, especially on steeper slopes. With the use of drainage geocomposites, the relevant built-up system can be pared back, while the number of vehicles required to carry materials can also be reduced. TeMa’s offering ranges from studded and micro-studded membranes to monofilaments laminated with nonwovens, and geonets with one or two nonwoven layers.
Erosion control
The top layer of the soil is eroded by the action of the elements — especially by the type of unpredictable and extremely violent weather events we’ve witnessed in recent years — triggering alarming landslips, which can undermine a site’s hydrogeology. To prevent issues of this kind, it’s essential to encourage vegetation (which serves as a form of natural erosion control) and protect the soil while it takes root by using natural or synthetic mats from TeMa.
TeMa at the 12th International Conference on Geosynthetics.
We too will be at the 12th edition of the International Conference on Geosynthetics that will take place in Rome, at the Parco della Musica auditorium from 17 to 21 September 2023, and which will involve a full programme of meetings between professionals (further information about the events here).
Four days of training and information meetings on geosynthetics, exploring all sub-types: woven and non-woven geotextiles, geogrids, geonets, geomats, drainage and reinforcement geocomposites, and geomembranes.
Geosynthetics are becoming increasingly popular in applications and fulfil various functions (often combined). For example:
- Drainage – drainage geocomposites and geonets.
- Filtration and Separation – woven geotextiles and non-woven geotextiles.
- Reinforcement – woven geotextiles and geogrids.
- Protection of waterproofing – studded membranes with truncated conical or star-shaped studs.
- Erosion control – geonets, geomats, biotextiles.
- Mechanical protection – non-woven geotextiles, composite geotextiles.
- Special applications – various geosynthetics made to specific requirements.
The main topics discussed will cover various fields of application, including anti-seismic design to road and railway embankments, erosion control, filtration and drainage functions, as well as an analysis of case studies.
The world of research is continuously evolving and the scheduled meetings will provide an excellent opportunity for sharing experiences and recent technical developments with engineers, geologists, consultants, contractors and whoever is involved in research and using geosynthetics.
During the exhibition event visitors will be able to take part in technical conferences, the Giroud lecture, special lectures and short courses , as well as visit the exhibition hall to meet manufacturers.
TeMa has thirty years of experience in using geosynthetics
The international event, entitled ‘Leading the way to a resilient planet’, fully represents the reason why TeMa began to manufacture and experiment with geosynthetics from the mid-1990s onwards: to research the most suitable technologies and materials for use in the construction of buildings and geotechnical works.
We have been involved in continuous interaction, also due to an increased awareness of major environmental issues. This has enabled us to broaden our range of products and expand in 80 countries worldwide.
Today, our catalogue includes many products that meet specific requirements for landfills, tunnels, road embankments, river banks and reinforced earth structures, gradually increasing performance for surface erosion control, rainwater drainage, and the reinforcement of grassy slopes.
The geosynthetics sector is rapidly developing and we are making huge investments, especially in research, so as to supply our customers with the best solutions, also tailor-made, for their projects. We share the same ‘urgency’ as our partners to pursue our unwavering ideal of respecting the environment and the hydrogeological protection of the land.
We look forward to seeing you in Rome from 17 to 21 September 2023, at Stand 22.
Meanwhile, you can discover all the details about the event here.
Reinforcement of slopes and embankments
Slopes and embankments can be used as road or railway embankments, raised flood banks and floodplains, and even vineyards, especially in a territory such as Italy, one of the countries with the largest number of UNESCO World Heritage landscapes in the world.Many of those greened terraces are true reinforced earth structures, with their stability guaranteed by a well-tested construction technique.
Stability for slopes and embankments
Reinforced earth structures are retaining works that allow slopes and embankments to be supported, including steep slopes. They do not involve the use of concrete constructions, which would be more detrimental to the landscape.
The soil has a natural capacity for compressive strength. When combined with geosynthetic grids (which have excellent tensile strength), they create a stable system, as the features of the two components provide a high-performance composite.
The open mesh structure allows reinforcement geogrids to develop passive resistance along the transverse ribs, as well as creep resistance of the geosynthetic grid in relation to the soil. The TeMa Geo Solutions range includes X-Grid geogrids, available in a variety of models depending on the type of project.
How to position the geogrid in the layering of a terrain?
Each slope needs to be carefully and expertly engineered. However, in addition to the need to reinforce the raised earth structure with geogrids, it is essential to ensure surface erosion control using synthetic or natural erosion control mats and shaping with electro-welded wire mesh formwork.
The X-Grid geogrid must be applied to each ‘block’ of soil supported by the formwork, positioned between the backfill soil and the erosion control mat. An external wrap-around part, measuring no more than 150 cm, must be provided for the formwork system by installing formwork stiffening ribs approximately 30 cm apart.
- Foundation soil
- Metal formwork
- Erosion control mat
- Geogrid
- Backfill soil
- Grassed surface
- Published in environmental, GEO, Geogrids, Reinforced earth structures
Technical considerations in building reinforced soil walls
Reinforced soil walls have proved highly popular in recent years and are produced wherever possible, taking the place of concrete-faced soil retaining wall systems.
Employed in a range of different environments, they bring significant advantages, both financial and environmental. Indeed, unlike concrete-faced soil retaining wall systems, they:
- are sustainable because they give a vegetated finish;
- are a great space-saving solution, with slopes as steep as 80° (compared to the 30-40° of natural soil embankments);
- result in less pollution given the smaller number of trucks required to carry construction materials;
- make use of the excavated earth for backfilling, provided it is compatible with stability standards, meaning no more material needs to be brought in;
- blend seamlessly with their surroundings once the slopes are grassed over, without becoming a blot on the landscape of our villages.
Whatever the case, before planning the work, there are a number of aspects and data to be taken into consideration.
Preliminary data needed
To start with, all essential technical information must be procured in order to be able to assess the feasibility of the project, such as:
- geological testing of the area on which the wall is planned to be built
- topographical surveys
- meaningful cross-sectional drawings showing the current condition
- geometry of the planned wall (face angle, height, division into tiers, slope on top)
- external loads applied to the structure (top loads in the event it needs to accommodate a car park or a road)
- what earthquake risk zone the area is in
- geotechnical properties (angle of shearing resistance, cohesion and density) of the earth behind the future wall, of the foundation soil, and of the backfill
- whether there are perched aquifers or seepage of a different nature.
At this point, the next step is to check design calculations using specific software.
Checking design calculations
Checking is performed to assess both internal and external stability. The following tests are carried out in the former case:
- reinforcement strength test, which assesses possible failure mechanisms and determines the spacing, length and tensile strength of the geosynthetics due to be laid
- pull-out test to check that the reinforcement applied does not break or slide out
- direct sliding test, to ensure there is no translational movement across the installation planes
- wrap-around test, to ensure that the length wrapped around the top of each individual layer is stable.
The checks to be carried out during the project’s execution to assess external stability consist in sliding, overturning, bearing capacity and global failure analysis.
Do you want to chat with one of our experts to find the solution that best suits your requirements?
We have 30 years of experience in the industry and can give you access to materials and solutions offering specific performance. Contact us!
Do you want to learn more about the full TeMa Geo Solutions product range for reinforced earth structures? Click here.
Cycle and pedestrian paths: solutions to make them safer and more attractive.
Longer days, milder afternoons, a great desire to spend time outdoors and perhaps get some physical exercise, but also go to work and school or visit a friend… These are all good reasons for using, when available, cycle and pedestrian paths, possibly far from urban traffic.
The advantages of sustainable mobility
We are increasingly talking about environmental sustainability and the physical and psychological benefits of physical exercise:
- Less air and noise pollution caused by traffic.
- Reduced transport costs.
- Greater freedom of movement.
- Enhanced green areas in cities.
- Better quality of life by doing a bit of sport on a daily basis.
TeMa Geo Solutions for safety and urban benefits
‘Unequipped’ roads can be hazardous for those who choose to get around by bicycle: for this and environmental reasons, cycle and pedestrian paths are the ideal solution, as they are increasingly becoming part of local government mobility plans.
TeMa Geo Solutions offers all its experience by combining reinforced earth structures and their feature of being green, with cycle and pedestrian paths.
An embankment can be made or a road widened with its sides sloping at 65°/70° using the T-System (consisting of formworks, X-Grid PET geogrids and K-Mat FG Green erosion control mats as facing), thereby making the path safe and allowing a slope to turn green again. Making a slope green again provides a natural erosion control function: to encourage it, TeMa Geo Solutions recommends installing natural or synthetic mats. To make the structure stable, the T-System for reinforced soils adopted by TeMa involves using X-Grid PET geogrids.
Reinforced earth structures and drainage
For the extension works at the Serravalle Retail Park shopping centre in the Piedmont region, we helped the company choose the solutions to implement and assisted with verifications.
The area covering about 2,000 sqm required some intervention work regarding reinforced earth structures and drainage. In particular, we undertook the preliminary work for extension works dating back to 2016.
To the south-west of the building, the soil was secured and then surfaces were replanted with greenery.
Let’s see how this was done in more detail.
Type of intervention
In order to make the slope in front of the complex secure, the intervention work involved constructing reinforced earth structures in several banks, more specifically 3 modules of 6 m in height each.
In addition, to manage the water coming from the hydro-geographic basin situated upstream of the area, specific surface drainage works were carried out.
The solution from TeMa Geo Solutions
For the reinforced earth structure, 3 modules were constructed with anchorage lengths of 7 m and a strength of 110 kN/m provided by X-Grid PET PC 110 geogrids.
As for drainage, instead, a Membrana Nera Geo was used, the 8 mm HDPE studded membrane bonded to a filter nonwoven geotextile with a PE slotted tube at the base.
The drainage system was also installed at the horizontal contact points of each berm to prevent future water seepage into the reinforced earth structure.
Controlling surface erosion with biomats and geomats
Soil erosion is an almost inevitable natural phenomenon that has become a greater concern in recent years due to the worsening climate situation – in Italy, for example, 132 extreme weather events were recorded between January and July 2022, a higher number than the annual average over the last decade – combined with long periods of drought.
Strong winds, heavy rain, hail and runoff tend to remove the surface layer of exposed soils, which often include organic matter and seeds. Climate change facilitates erosion, making it not only inevitable but also hazardous if left uncontrolled.
It’s essential to counter or mitigate the phenomenon: soil provides us with food, biomass and raw materials; human activities take place on it and it’s part of the landscape and our cultural heritage.
Which structures are more subject to surface erosion?
The areas of application most affected by the erosive action of the climate are:
- slopes and the sides of landfills and contaminated sites, and those that have been grassed for appreciable aesthetic improvement;
- reinforced earth structures, more specifically terracing in vineyards and the embankments of canals or rivers;
- ascending/descending ramps from flyovers, tunnel entrances and noise barriers on roads and railways;
- dry, rocky slopes, of all angles, that shape the terrain of Italy.
The effects of surface erosion
The uncontrolled removal of the surface topsoil and the failure of vegetation to take root results in ‘thinning’ of the soil and a risk to the stability of sloping areas.
What can be done to prevent surface erosion?
We should begin by pointing out that a case-by-case assessment is required that considers many variables, such as the nature and uniformity of the soil, the slope gradient, the type of slope (dry or rocky) and the weather conditions in the area where intervention work is to be carried out.
In general, vegetation, whatever type it is, has a natural ability to protect soils from erosion. So the best course of action is to quickly encourage grassing and then apply biodegradable mats made of jute, straw, coconut and cellulose fibre, which can also be pre-seeded.
TeMa Geo Solutions recommends biomats such as Ecovermat, Ecovermat P and PC, and Ecovernet.
Alternatively, or combined with these, synthetic geomats, mainly made of polymer monofilaments, can be used.
Once laid, they are covered with another layer of soil: in this way, the roots of growing vegetation will become entangled with the geomat, creating an almost permanent erosion protection system.
Once again, TeMa Geo Solutions offers a wide range of geomats to choose from.
Uncertain about what to choose? We can help you. CONTACT US!
Reinforced earth structures as noise barriers
Hearing the noise of traffic outside your window all day long is irritating and distracting and, in the long term, also harmful to your health.
This is why the WHO and a number of laws govern the use of noise remediation systems in cities: the Framework Law no. 447 of 1995 for Italy and the European Directive on Environmental Noise no. 49/2022. If the cause of the noise cannot be addressed, the solution is to install protective barriers. Various kinds can be used, but in this case we focus on reinforced earth structures that require specific measures, which we discuss here.
For example, the Pedemontana Veneta is a new toll motorway in Italy: nearly 100 km long. Almost entirely in operation in the north-east of the Veneto region, the main route of this motorway runs through a deep trench in order to minimise the ‘territorial’ and environmental impact on the surrounding area. This means that long sloping areas of reinforced earth can be found along the sides of the motorway, with rows of trees and hedges for 58.61 km and green areas covering 1,333,410 square metres of hedgerows, groves, grassy slopes and tree-lined meadows.
A focus on noise with much regard for the landscape.
What do reinforced earth noise barriers consist of?
For this type of embankment with its typical trapezoidal shape, earth is used that will be covered by vegetation over time. Geosynthetic reinforcements and geogrids are added to support the earth, which already has good compressive strength. These are inserted horizontally into the ground and develop friction and tension that stabilise the structure, increasing its resistance to stress.
The TeMa Geo Solutions offer includes the X-Grid Pet PVC range of geogrids, with different resistance values, which are ideal for all kinds of contexts.
Another aspect to bear in mind is surface erosion of the soil: to counteract this, synthetic geomats are applied, also with a mulching function to encourage the growth of grass cover, or natural fibre bionets.
Also in this case, TeMa Geo Solutions offers a wide choice ranging from Ecovermat F Grass and Ecovernet FJ to the K-Mat range.
Why use a vegetation barrier as a protective noise barrier?
A vegetation barrier has an unquestionable ability to limit the spread of sound waves: some of them are absorbed, some reflected and some deflected. As a result, the amount of sound waves reaching the receiver is greatly reduced and noise can be dampened by several decibels.
The advantages of a reinforced earth sound-deadening barriera
Creating reinforced earth structures brings considerable advantages:
- it costs less because you can often use earth available on-site
- no special maintenance is required other than regular trimming.
- it helps the environment and integrates with it: the use of vegetation also reduces vehicle emissions by absorbing CO 2 and purifying the air.
We will be at the EuroGeo7 Conference in Warsaw
After being postponed for so many months due to the health emergency, EUROGEO7, the 7th European Geosynthetics Conference will take place at last in Warsaw from 4 to 7 September 2022. We will be participating with our thirty years of experience and our innovative flow of products and functions.
We will be attending with ourTeMa Geo Solutions division, specialized in developing innovative technologies and products for protection, maintenance, retention, reinforcement and drainage in environmental works.
We have achieved these goals because since 1993, when TeMa was established, geosynthetic products have been our targeted approach to geotechnical and environmental applications. At a time when there was little talk of ecosystems, we developed considerable experience in this field, deploying new technologies and finding crucial improvements in terms of durability and less invasive intervention works using geosynthetic products.
The many fields of application range from the most important functions to be addressed in the fields of geotechnical engineering, reinforced earth structures and reinforced soil, to name but a few. They are highly impressive in the fields of hillside agriculture and the urban regeneration of small villages: drainage and filtration for landfills and contaminated sites; roads, railways and other transport applications; rainwater management.
What will TeMa Geo Solutions explore?
The focus is on geosynthetic products and the aspects that make them versatile, high-performance and innovative in geotechnical engineering applications. In particular, we will be focusing on TeMa Geo Solutions technologies for:
- removing seepage water using drainage geocomposites bonded with a nonwoven geotextile;
- reinforcement and stabilization with geogrids;
- the drainage capacity for the cap, bottom and sides of landfills with geonets;
- erosion control and drainage with geomats.
Our technicians will be available to provide catalogues and data sheets with performance details.
To learn more: https://www.temacorporation.com/geo-applications/
- Published in CORPORATION, Exhibitions and events, news, TeMa Technologies and Materials
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