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Geosynthetic
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. History Inclusions of different sorts mixed with soil have been ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cellular Confinement
Cellular confinement systems (CCS)—also known as geocells—are widely used in construction for erosion control, soil stabilization on flat ground and steep slopes, channel protection, and structural reinforcement for load support and earth retention. Typical cellular confinement systems are geosynthetics made with ultrasonically welded high-density polyethylene (HDPE) strips or novel polymeric alloy (NPA)—and expanded on-site to form a honeycomb-like structure—and filled with sand, soil, rock, gravel or concrete. History of cellular confinement Research and development of cellular confinement systems (CCS) began with the U.S. Army Corps of Engineers in 1975 to devise a method for building tactical roads over soft ground. Engineers found that sand-confinement systems performed better than conventional crushed stone sections and they could provide an expedient construction technique for access roads over soft ground, without being adversely affected by wet weather cond ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geotechnical Engineering
Geotechnical engineering is the branch of civil engineering concerned with the engineering behavior of earth materials. It uses the principles of soil mechanics and rock mechanics for the solution of its respective engineering problems. It also relies on knowledge of geology, hydrology, geophysics, and other related sciences. Geotechnical (rock) engineering is a subdiscipline of geological engineering. In addition to civil engineering, geotechnical engineering also has applications in military, mining, petroleum, coastal engineering, and offshore construction. The fields of geotechnical engineering and engineering geology have knowledge areas that overlap, however, while geotechnical engineering is a specialty of civil engineering, engineering geology is a specialty of geology: They share the same principles of soil mechanics and rock mechanics, but differ in the application. History Humans have historically used soil as a material for flood control, irrigation purposes, buria ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geosynthetic Clay Liners
Different types of fabric used for geosynthetic clay liners. Geosynthetic clay liners (GCLs) are factory manufactured hydraulic barriers consisting of a layer of bentonite or other very low-permeability material supported bgeotextilesand/or geomembranes, mechanically held together by needling, stitching, or chemical adhesives. Due to environmental laws, any seepage from landfills must be collected and properly disposed of, otherwise contamination of the surrounding ground water could cause major environmental and/or ecological problems. The lower the hydraulic conductivity the more effective the GCL will be at retaining seepage inside of the landfill. Bentonite composed predominantly (>70%) of montmorillonite or other expansive clays, are preferred and most commonly used in GCLs. A general GCL construction would consist of two layers of geosynthetics stitched together enclosing a layer of natural or processed sodium bentonite. Typically, woven and/or non-woven textile geosy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geotextiles
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 two basic forms: woven (resembling mail bag sacking) and nonwoven (resembling felt). Geotextile composites have been introduced and products such as geogrids and meshes have been developed. Geotextiles are durable and are able to soften a fall. 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. History Geotextiles were originally intended to be a substitute for 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 c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geonets
A geonet is a geosynthetic material similar in structure to a geogrid, consisting of integrally connected parallel sets of ribs overlying similar sets at various angles for in-plane drainage of liquids or gases. Geonets are often laminated with geotextiles on one or both surfaces and are then referred to as drainage geocomposites. They are competitive with other drainage geocomposites having different core configurations. Manufacturing Geonets are formed by a continuous extrusion process into a netlike configuration of parallel sets of homogeneously interconnected ribs. There are three categories of geonets. The following are illustrated: * ''Biplanar geonets:'' These are the original and most common types and consist of two sets of intersecting ribs at different angles and spacings. The ribs themselves are of different sizes and shapes for different styles. * ''Triplanar geonets:'' These have parallel central ribs with smaller sets of ribs above and beneath mainly for geome ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geomembranes
A geomembrane is very low permeability synthetic membrane liner or barrier used with any geotechnical engineering related material so as to control fluid (liquid or gas) migration in a human-made project, structure, or system. Geomembranes are made from relatively thin continuous polymeric sheets, but they can also be made from the impregnation of geotextiles with asphalt, elastomer or polymer sprays, or as multilayered bitumen geocomposites. Continuous polymer sheet geomembranes are, by far, the most common. Manufacturing The manufacturing of geomembranes begins with the production of the raw materials, which include the polymer resin, and various additives such as antioxidants, plasticizers, fillers, carbon black, and lubricants (as a processing aid). These raw materials (i.e., the "formulation") are then processed into sheets of various widths and thickness by extrusion, calendering, and/or spread coating. Geomembranes dominate the sales of geosynthetic products, at US$1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geocomposites
Geocomposite is a composition / combination of two or more geosynthetic materials to perform multiple number of geosynthetic functions for specific civil engineering application(s) the purpose of providing this composition is to minimize the application costs whereas the technical properties of the soil or the geotechnical structure are enhanced. There are five basic functions that can be provided: separation, reinforcement, filtration, drainage, and containment. Geotextile-geonet composites When a geotextile is used on one or both sides of a geonet, the separation and filtration functions are always satisfied, but the drainage function is vastly improved in comparison to geotextiles by themselves. Such geocomposites are regularly used in intercepting and conveying leachate in landfill liner and cover systems and for conducting vapor or water beneath pond liners of various types. These drainage geocomposites also make excellent drains to intercept water in a capillary zone where ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geogrid
A geogrid is geosynthetic material used to reinforce soils and similar materials. Soils pull apart under tension. Compared to soil, geogrids are strong in tension. This fact allows them to transfer forces to a larger area of soil than would otherwise be the case. Geogrids are commonly made of polymer materials, such as polyester, polyvinyl alcohol, polyethylene or polypropylene. They may be woven or knitted from yarns, heat-welded from strips of material, or produced by punching a regular pattern of holes in sheets of material, then stretched into a grid. The development of methods of preparing relatively rigid polymeric materials by tensile drawing, in a sense "cold working," raised the possibility that such materials could be used in the reinforcement of soils for walls, steep slopes, roadway bases and foundation soils. The principal function of geogrids is for reinforcement. This area, as with many other geosynthetics, is very active, with a number of different products, mat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Road
A road is a linear way for the conveyance of traffic that mostly has an improved surface for use by vehicles (motorized and non-motorized) and pedestrians. Unlike streets, the main function of roads is transportation. There are many types of roads, including parkways, avenues, controlled-access highways (freeways, motorways, and expressways), tollways, interstates, highways, thoroughfares, and local roads. The primary features of roads include lanes, sidewalks (pavement), roadways (carriageways), medians, shoulders, verges, bike paths (cycle paths), and shared-use paths. Definitions Historically many roads were simply recognizable routes without any formal construction or some maintenance. The Organization for Economic Co-operation and Development (OECD) defines a road as "a line of communication (travelled way) using a stabilized base other than rails or air strips open to public traffic, primarily for the use of road motor vehicles running on their own wheels", whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geofoam
Geofoam is expanded polystyrene (EPS) or extruded polystyrene (XPS) manufactured into large lightweight blocks. The blocks vary in size but are often . The primary function of geofoam is to provide a lightweight void fill below a highway, bridge approach, embankment or parking lot. EPS Geofoam minimizes settlement on underground utilities. Geofoam is also used in much broader applications, including lightweight fill, green roof fill, compressible inclusions, thermal insulation, and (when appropriately formed) drainage. Geofoam shares principles with geocombs (previously called ultralight cellular structures) which has been defined as "any manufactured material created by an extrusion process that results in a final product that consists of numerous open-ended tubes that are glued, bonded, fused or otherwise bundled together." The cross-sectional geometry of an individual tube typically has a simple geometric shape (circle, ellipse, hexagon, octagon, etc.) and is on the order o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reservoir
A reservoir (; from French ''réservoir'' ) is an enlarged lake behind a dam. Such a dam may be either artificial, built to store fresh water or it may be a natural formation. Reservoirs can be created in a number of ways, including controlling a watercourse that drains an existing body of water, interrupting a watercourse to form an embayment within it, through excavation, or building any number of retaining walls or levees. In other contexts, "reservoirs" may refer to storage spaces for various fluids; they may hold liquids or gasses, including hydrocarbons. ''Tank reservoirs'' store these in ground-level, elevated, or buried tanks. Tank reservoirs for water are also called cisterns. Most underground reservoirs are used to store liquids, principally either water or petroleum. Types Dammed valleys Dammed reservoirs are artificial lakes created and controlled by a dam A dam is a barrier that stops or restricts the flow of surface water or underground streams ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soil
Soil, also commonly referred to as earth or dirt, is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Some scientific definitions distinguish ''dirt'' from ''soil'' by restricting the former term specifically to displaced soil. Soil consists of a solid phase of minerals and organic matter (the soil matrix), as well as a porous phase that holds gases (the soil atmosphere) and water (the soil solution). Accordingly, soil is a three-state system of solids, liquids, and gases. Soil is a product of several factors: the influence of climate, relief (elevation, orientation, and slope of terrain), organisms, and the soil's parent materials (original minerals) interacting over time. It continually undergoes development by way of numerous physical, chemical and biological processes, which include weathering with associated erosion. Given its complexity and strong internal connectedness, soil ecologists regard soil as an ecosystem. Most ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
