Geotextile

Geotextiles are permeable fabrics which, when used in association with soil, have the ability to separate, filter, reinforce, protect, or drain. Typically made from polypropylene or polyester, geotextile fabrics come in three basic forms: woven (resembling mail bag sacking), needle punched (resembling felt), or heat bonded (resembling ironed felt).

Geotextile composites have been introduced and products such as geogrids and meshes have been developed. Geotextiles are able to withstand many things, are durable, and are able to soften a fall if someone falls down. Overall, these materials are referred to as geosynthetics and each configuration—geonets, geosynthetic clay liners, geogrids, geotextile tubes, and others—can yield benefits in geotechnical and environmental engineering design.

Kliffende, Island Sylt, 1999
Geotextile sandbags protected the historic house Kliffende on Sylt island against storms, which eroded the cliffs left and right from the sandbag barrier.[1]
Mega sand container
Geotextile sandbags can be ca. 20 m long, such as those used for the artificial reef at Narrow Neck, Queensland.[1]

History

Geotextiles were originally intended to be an alternative to granular soil filters. The original, and still sometimes used, term for geotextiles is filter fabrics. Work originally began in the 1950s with R.J. Barrett using geotextiles behind precast concrete seawalls, under precast concrete erosion control blocks, beneath large stone riprap, and in other erosion control situations.[2] He used different styles of woven monofilament fabrics, all characterized by a relatively high percentage open area (varying from 6 to 30%). He discussed the need for both adequate permeability and soil retention, along with adequate fabric strength and proper elongation and set the tone for geotextile use in filtration situations.

Applications

Silt fence EPA
A silt fence on a construction site.

Geotextiles and related products have many applications and currently support many civil engineering applications including roads, airfields, railroads, embankments, retaining structures, reservoirs, canals, dams, bank protection, coastal engineering and construction site silt fences or geotube. Usually geotextiles are placed at the tension surface to strengthen the soil. Geotextiles are also used for sand dune armoring to protect upland coastal property from storm surge, wave action and flooding. A large sand-filled container (SFC) within the dune system prevents storm erosion from proceeding beyond the SFC. Using a sloped unit rather than a single tube eliminates damaging scour.

Erosion control manuals comment on the effectiveness of sloped, stepped shapes in mitigating shoreline erosion damage from storms. Geotextile sand-filled units provide a "soft" armoring solution for upland property protection. Geotextiles are used as matting to stabilize flow in stream channels and swales.[3][4]

Geotextiles can improve soil strength at a lower cost than conventional soil nailing.[5] In addition, geotextiles allow planting on steep slopes, further securing the slope.

Geotextiles have been used to protect the fossil hominid footprints of Laetoli in Tanzania from erosion, rain, and tree roots.[6]

In building demolition, geotextile fabrics in combination with steel wire fencing can contain explosive debris.[7]

Coir (coconut fiber) geotextiles are popular for erosion control, slope stabilization and bioengineering, due to the fabric's substantial mechanical strength.[3]:App. I.E Coir geotextiles last approximately 3 to 5 years depending on the fabric weight. The product degrades into humus, enriching the soil.[8]

Design methods

While many possible design methods or combinations of methods are available to the geotextile designer, the ultimate decision for a particular application usually takes one of three directions: design by cost and availability, design by specification, or design by function. Extensive literature on design methods for geotextiles has been published in the peer reviewed journal Geotextiles and Geomembranes.

See also

References

  1. ^ a b Müller, W. W.; Saathoff, F. (2015). "Geosynthetics in geoenvironmental engineering". Science and Technology of Advanced Materials. 16 (3): 034605. Bibcode:2015STAdM..16c4605M. doi:10.1088/1468-6996/16/3/034605. PMC 5099829. PMID 27877792.
  2. ^ Barrett, R. J., "Use of Plastic Filters in Coastal Structures," Proceedings from the 16th International Conference Coastal Engineers, Tokyo, September 1966, pp. 1048–1067
  3. ^ a b Dane County Department of Land and Water Resources (2007). Dane County Erosion Control and Stormwater Management Manual (PDF) (Report). Madison, WI. Retrieved 2010-02-09.
  4. ^ Massachusetts Department of Environmental Protection (2003). Massachusetts Erosion and Sediment Control Guidelines for Urban and Suburban Areas (PDF) (Report). Boston, MA. pp. 73–74.
  5. ^ Morgan, Roy P.C.; Rickson, R.J. (2011). Slope Stabilization and Erosion Control: A Bioengineering Approach. London: Taylor & Francis. ISBN 9780419156307.
  6. ^ Renfrew, Colin and Paul Bahn, Archaeology. 4th ed. New York: Thames 2004. ISBN 978-0-500-28441-4.
  7. ^ WGBH Boston (December 1996). "Interview with Stacey Loizeaux". NOVA Online. Public Broadcasting Service. Retrieved 2009-04-29. Other preparatory operations involve covering/wrapping the columns first with chain link fences and then with geotextile fabric, which is very puncture resistant and has a very high tensile strength. It allows the concrete to move, but it keeps the concrete from flying. The chain link catches the bigger material and the fabric catches the smaller material from flying up and out.
  8. ^ Richards, Davi (2006-06-02). "Coir is sustainable alternative to peat moss in the garden". Garden Hints. Corvallis, OR: Oregon State University Extension Service. Retrieved 2013-03-06.

Further reading

  • Koerner, R. M. (2012). Designing With Geosynthetics, 6th Edition, Xlibris Publishing Co., 914 pgs.
  • Koerner, R. M., Editor (2016). Geotextiles: From Design to Applications, Woodhead Publishing Co., AMsterdam, 617 pgs.
  • John, N. W. M. (1987). Geotextiles, Blackie Publishing Ltd., Glasgow, 347 pgs.
Beach nourishment

Beach nourishment (also referred to as beach renourishment, beach replenishment, or sand replenishment) describes a process by which sediment, usually sand, lost through longshore drift or erosion is replaced from other sources. A wider beach can reduce storm damage to coastal structures by dissipating energy across the surf zone, protecting upland structures and infrastructure from storm surges, tsunamis and unusually high tides. Beach nourishment is typically part of a larger coastal defense scheme. Nourishment is typically a repetitive process since it does not remove the physical forces that cause erosion but simply mitigates their effects.

The first nourishment project in the United States was at Coney Island, New York in 1922 and 1923. It is now a common shore protection measure used by public and private entities.

Bishan-Ang Mo Kio Park

Bishan-Ang Mo Kio Park (formerly known as Bishan Park) is a major park in Singapore, located in the popular heartland of Bishan. Serving the residents of Bishan and Ang Mo Kio, the park sits entirely within Bishan, running along the Ang Mo Kio–Bishan boundary line, which is situated at Ang Mo Kio Avenue 1. In the middle of the park lies the Kallang River, which runs through it in the form of a flat riverbed.

Drainage

Drainage is the natural or artificial removal of a surface's water and sub-surface water from an area with excess of water. The internal drainage of most agricultural soils is good enough to prevent severe waterlogging (anaerobic conditions that harm root growth), but many soils need artificial drainage to improve production or to manage water supplies.

Geocomposite

The basic philosophy behind geocomposite materials is to combine the best features of different materials in such a way that specific applications are addressed in the optimal manner and at minimum cost. Thus, the benefit/cost ratio is maximized. Such geocomposites will generally be geosynthetic materials, but not always. In some cases it may be more advantageous to use a nonsynthetic material with a geosynthetic one for optimum performance and/or least cost. As seen in the following, the number of possibilities is huge — the only limits being one's ingenuity and imagination.

There are five basic functions that can be provided: separation, reinforcement, filtration, drainage, and containment.

Geosynthetics

Geosynthetics are synthetic products used to stabilize terrain. They are generally polymeric products used to solve civil engineering problems. This includes eight main product categories: geotextiles, geogrids, geonets, geomembranes, geosynthetic clay liners, geofoam, geocells and geocomposites. The polymeric nature of the products makes them suitable for use in the ground where high levels of durability are required. They can also be used in exposed applications. Geosynthetics are available in a wide range of forms and materials. These products have a wide range of applications and are currently used in many civil, geotechnical, transportation, geoenvironmental, hydraulic, and private development applications including roads, airfields, railroads, embankments, retaining structures, reservoirs, canals, dams, erosion control, sediment control, landfill liners, landfill covers, mining, aquaculture and agriculture.

Gravel

Gravel is a loose aggregation of rock fragments. Gravel is classified by particle size range and includes size classes from granule- to boulder-sized fragments. In the Udden-Wentworth scale gravel is categorized into granular gravel (2 to 4 mm or 0.079 to 0.157 in) and pebble gravel (4 to 64 mm or 0.2 to 2.5 in). ISO 14688 grades gravels as fine, medium, and coarse with ranges 2 mm to 6.3 mm to 20 mm to 63 mm. One cubic metre of gravel typically weighs about 1,800 kg (or a cubic yard weighs about 3,000 pounds).

Gravel is an important commercial product, with a number of applications. Many roadways are surfaced with gravel, especially in rural areas where there is little traffic. Globally, far more roads are surfaced with gravel than with concrete or asphalt; Russia alone has over 400,000 km (250,000 mi) of gravel roads. Both sand and small gravel are also important for the manufacture of concrete.

Irrigation

Irrigation is the application of controlled amounts of water to plants at needed intervals. Irrigation helps to grow agricultural crops, maintain landscapes, and revegetate disturbed soils in dry areas and during periods of less than average rainfall. Irrigation also has other uses in crop production, including frost protection, suppressing weed growth in grain fields and preventing soil consolidation. In contrast, agriculture that relies only on direct rainfall is referred to as rain-fed or dry land farming.

Irrigation systems are also used for cooling livestock, dust suppression, disposal of sewage, and in mining. Irrigation is often studied together with drainage, which is the removal of surface and sub-surface water from a given area.

Irrigation has been a central feature of agriculture for over 5,000 years and is the product of many cultures. Historically, it was the basis for economies and societies across the globe, from Asia to the Southwestern United States.

Land drains

The purpose of a land drain is to allow water in wet or swampy ground to rapidly drain away or to relieve hydrostatic pressure. They are subterranean linear structures which are laid to a fall which should be as steep as practicable. They are used in agriculture and in building construction sites. Modern land drains take the form of a perforated or discontinuous (i.e. open-jointed) pipe. Typically, the land drains conduct the surplus water to an open ditch or natural water source.

Manzanillo, Colima

Manzanillo (Spanish pronunciation: [mansaˈnijo]) is a city, seat of Manzanillo Municipality, in the Mexican state of Colima. The city, located on the Pacific Ocean, contains Mexico's busiest port that is responsible for handling Pacific cargo for the Mexico City area. It is the largest producing municipality for the business sector and tourism in the state of Colima.

The city is known as the "sailfish capital of the world". Since 1957, it has hosted important national and international fishing competitions, such as the Dorsey Tournament, making it a very attractive fishing destination. Manzanillo has become one of the country's most important tourist resorts, and its excellent hotels and restaurants continue to meet the demands of both national and international tourism.

Multi-purpose reef

A multi-purpose reef, also commonly known as an artificial surfing reef or surf reef, is a structure located offshore designed to induce wave breaking in a manner that creates a wave suitable for surfing or body boarding. Artificial surfing reefs can exist in many different configurations and be built from a variety of different materials. To date there have been fewer than ten attempts to build such a structure worldwide.

Artificial surfing reefs are a variation of a long existing type of coastal structure known as a submerged breakwater. Submerged breakwaters have historically been used for coastal protection. If an offshore structure is specifically designed for both the improvement of a recreational resource (i.e. wave riding) and coastal protection or stabilization, it can be classified as a multi-purpose reef.

Nonwoven fabric

Non-woven fabric is a fabric-like material made from staple fibre (short) and long fibres (continuous long), bonded together by chemical, mechanical, heat or solvent treatment. The term is used in the textile manufacturing industry to denote fabrics, such as felt, which are neither woven nor knitted. Some non-woven materials lack sufficient strength unless densified or reinforced by a backing. In recent years, non-woven have become an alternative to polyurethane foam.

Pond liner

A pond liner is an impermeable geomembrane used for retention of liquids, including the lining of reservoirs, retention basins, hazardous and nonhazardous surface impoundments, garden ponds and artificial streams in parks and gardens.

Revetment

In stream restoration, river engineering or coastal engineering, revetments are sloping structures placed on banks or cliffs in such a way as to absorb the energy of incoming water. In military engineering they are structures, again sloped, formed to secure an area from artillery, bombing, or stored explosives. River or coastal revetments are usually built to preserve the existing uses of the shoreline and to protect the slope, as defense against erosion.

Sand

Sand is a granular material composed of finely divided rock and mineral particles. It is defined by size, being finer than gravel and coarser than silt. Sand can also refer to a textural class of soil or soil type; i.e., a soil containing more than 85 percent sand-sized particles by mass.The composition of sand varies, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal settings is silica (silicon dioxide, or SiO2), usually in the form of quartz. The second most common type of sand is calcium carbonate, for example, aragonite, which has mostly been created, over the past half billion years, by various forms of life, like coral and shellfish. For example, it is the primary form of sand apparent in areas where reefs have dominated the ecosystem for millions of years like the Caribbean.

Sand is a non-renewable resource over human timescales, and sand suitable for making concrete is in high demand. Desert sand, although plentiful, is not suitable for concrete. 50 billion tons of beach sand and fossil sand is used each year for construction.

Secondary spill containment

Secondary spill containment is the containment of hazardous liquids in order to prevent pollution of soil and water. Common techniques include the use of spill berms to contain oil-filled equipment, fuel tanks, truck washing decks, or any other places or items that may leak hazardous liquids.

Silt

Silt is granular material of a size between sand and clay, whose mineral origin is quartz and feldspar. Silt may occur as a soil (often mixed with sand or clay) or as sediment mixed in suspension with water (also known as a suspended load) and soil in a body of water such as a river. It may also exist as soil deposited at the bottom of a water body, like mudflows from landslides. Silt has a moderate specific area with a typically non-sticky, plastic feel. Silt usually has a floury feel when dry, and a slippery feel when wet. Silt can be visually observed with a hand lens, exhibiting a sparkly appearance. It also can be felt by the tongue as granular when placed on the front teeth (even when mixed with clay particles).

Subsurface textile irrigation

Subsurface Textile Irrigation (SSTI) is a technology designed specifically for subsurface irrigation in all soil textures from desert sands to heavy clays. Use of SSTI will significantly reduce the usage of water,

fertilizer and herbicide. It will lower on-going operational costs and, if maintained properly, will last for decades. By delivering water and nutrients directly to the root zone, plants are healthier and have a far greater yield.

It is the only irrigation system that can safely use recycled water or treated water without expensive “polishing” treatment because water never reaches the surface.

A typical subsurface textile irrigation system has an impermeable base layer (usually polyethylene or polypropylene), a drip line running along that base, a layer of geotextile on top of the drip line and, finally, a narrow impermeable layer on top of the geotextile (see diagram). Unlike standard drip irrigation, the spacing of emitters in the drip pipe is not critical as the geotextile moves the water along the fabric up to 2m from the dripper.

SSTI is installed 15–20 cm below the surface for residential/commercial applications and 30–50 cm for agricultural applications.

Track surface

The track surface of a horse racing track refers to the material of which the track is made. There are three types of track surfaces used in modern horse racing. These are:

Turf, the most common track surface in Europe

Dirt, the most common track surface in the US

Artificial or Synthetic, the collective term for a number of proprietary man-made surfaces in use at a number of locations around the world.The style of racing differs between surfaces, with dirt races tending to have the fastest pace, while turf racing often comes down to a sprint in the stretch. Races on artificial surfaces tend to play out somewhere in between. Anecdotally, American bettors consider dirt racing to be more predictable, which makes it a more popular medium for betting purposes. Weather conditions affect the speed of the different surfaces too, and grading systems have been developed to indicate the track condition (known as the "going" in the UK and Ireland). Turf surfaces are the most affected by changes in the weather, and many turf horses will have a strong preference for a specific type of going.

Trench

A trench is a type of excavation or depression in the ground that is generally deeper than it is wide (as opposed to a wider gully, or ditch), and narrow compared with its length (as opposed to a simple hole).In geology, trenches are created as a result of erosion by rivers or by geological movement of tectonic plates. In the civil engineering field, trenches are often created to install underground infrastructure or utilities (such as gas mains, water mains or telephone lines), or later to access these installations. Trenches have also often been dug for military defensive purposes. In archaeology, the "trench method" is used for searching and excavating ancient ruins or to dig into strata of sedimented material.

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