What are prefabricated vertical drains?
Prefabricated Vertical Drains, also known as Wick Drains or band drains are prefabricated geotextile filter-wrapped plastic strips with moulded channels. These act as drainage paths to take pore water out of soft compressible soils that consolidate faster under a constant surcharge load.
How does prefabricated vertical drain work?
The prefabricated vertical drains are made up of a core material, usually of plastic that is wrapped with the spun-bond non-woven geotextiles as an outer layer and acts as a filter fabric. The geotextile filters the soil from entering the water channels and flooding the drain.
What is vertical drainage system?
Vertical drainage is the system of boreholes for lands drainage, from which water is pumped out by pumps with submerged electric motors. The water pumped out of the wells is diverted by open canals or pipelines to main canals and outfall drains. …
What is the function of geocomposite?
Geocomposites are used for basic functions of roadways such as separation, drainage, filtration, and reinforcement. Geocomposites can be used to increase the strength and stability of underlying soil in a roadway.
What is the function of vertical drain?
Vertical drains or also known as wick drains are used to shorten the dissipation path of the excess pore water and to accelerate the consolidation process to a few months or even weeks when the PVD is placed at close center to center distances.
What is preloading and vertical drains?
Preloading with vertical drains is a successful ground improvement technique, which involves the loading of the ground surface to induce most of the ultimate settlement. Usually, a surcharge load equal to or greater than the expected to accelerate consolidation with the aid of vertical drains [3].
What are the types of geocomposite?
Geocomposite materials include geotextile-geonets, geotextile-geogrids, geotextile-geomembranes, geomembrane-geonets, geosynthetics clay liner (GCL), geotextile-polymeric cores, or three-dimensional polymeric cell structures. Various forms of geocomposite materials are presented in Fig.
What is geocomposite drainage?
Geocomposite Drainage Systems are engineered to replace costly, conventional open graded aggregate and/or perforated- pipe subsurface drainage systems. The Geocomposite Drainage System is created by laminating a filtration geotextile on one or both sides of a Geonet.
What are the components of drains?
As was discussed in Chapter 3, a surface drainage system always has two components: (1) land forming, which is bedding, land grading, or land planing, and (2) the construction of field and collector drains. The three types of land forming are discussed first, followed by the design and construction of open drains.
What is advantage of using vertical drains along with preloading?
Pre-load enables consolidation of soil in vertical direction only and hence sand drains in addition to pre-loading are used to accelerate the consolidation of soils. This results in reduction of lesser pre-load.
What are geosynthetic materials?
As per the definition of American Society for Testing and Materials (ASTM), a geosynthetic material is a planar product manufactured from a polymeric material that is used with soil, rock, earth, or other geotechnical related material as an integral part of a civil engineering project, structure, or system.
Which kind of geocomposite product is best to provide reinforcement and drainage functions?
Geotextile-geogrid composites A needle punched nonwoven geotextile bonded to a geogrid provides in-plane drainage while the geogrid provides tensile reinforcement. Such geotextile-geogrid composites are used for internal drainage of low-permeability backfill soils for reinforced walls and slopes.
What does a prefabricated vertical drain look like?
The prefabricated vertical drains are made up of a core material, usually of plastic that is wrapped with the spun-bond non-woven geotextiles as an outer layer and acts as a filter fabric. The geotextile filters the soil from entering the water channels and flooding the drain.
Which is the best company for vertical drainage?
Since the development of the synthetic prefabricated vertical drain (PVD) also known as wick drain in the late 1970ties, Cofra is worldwide one of the leading contractors. Cofra has installation rigs available for each soil type, varying from very soft soils to very stiff intermediate layers.
Why are geotextile / prefabricated vertical drains ( PVD )?
We carry a variety of tests on Geotextile/Prefabricated Vertical Drains (PVD) to ensure that your preconstruction soil consolidation through wicker drain installation will be conducted in a structured and seamless manner. This will help you mitigate the risk of delay in the project completion and accidents.
Why does Cofra use prefabricated vertical drains?
The prefabricated vertical drain (PVD) used by Cofra are specially designed to work effectively under high settlements (i.e. under buckled or kinked conditions). Highly permeable soils like sand can adjust rapidly to loads and the corresponding compression / reduction in voids due to the ability to easily drain the excess porewater.