Tile drainage

The drainage with technical systems is used to counteract water logging on buildings and on agricultural land. For this, the water is captured and derived targeted. This water logging can have different causes:

• Extraneous water inflow,
• Backwater,
• Retained water.

In agricultural application changes the type of use come as other causes into consideration how the extensification of land which leads to reduced plant growth and hence less evaporation of the plants or the transition to irrigation, which may require drainage of excess water.

As a technical system, the drainage tube is mainly disseminated. In special cases, artesian well are used, for example, when there is no free flow. The special requirement in special structures to provide both support systems as well as drainage systems can be advantageously solved by a drainage wall.

• 2.1 Drainage pile
• 2.2 Drainage wall
• 2.3 Drainage anchor

• 7.1 goals
• 7.2 Drainage measures 7.2.1 Benefits of an Effective drainage system

Drainage for civil engineering purposes

Basics

The drainage of buildings, a protecting system into consideration when seepage and water layers from the bottom (foundation ) and below grade walls should be kept away. If the groundwater level consistently higher than the sole, then the structure is watertight perform, for example, by a white tub, as a permanent lowering of the water table is not secure and is not desirable because of the additional amounts of water flowing.

The selection and design of technical systems drainage requires knowledge and consideration of the following key factors ahead:

• Water balance with knowledge of the soil water content in Dränbereich as well as the inflow and outflow of water in the area to be protected,
• Water conductivity of the layers of soil, especially in Dränbereich,
• Possibilities of spatial arrangement of the drainage systems ( Drängeometrie ) and their water removal.

In the technical assessment and design of drainage systems, these boundary conditions are recognized by the following characteristics:

• Drainage geometry with the expansion and elevation of the land
• Soil properties as saturated and partially saturated hydraulic conductivity, expressed as flow length per unit of time, usually in m / s

The detailed calculation requires the solution of differential equations, for which most computer programs are used. In addition, use of the formulas can be used, such as the formula of Hooghoud.

Regulations and construction

The requirements for drainage systems for buildings are given in DIN 4095. Irrespective of this, structural waterproofing is to ensure the technical solutions and requirements in DIN 18195 are set.

A functional drainage on structures is accomplished by the contact with the ground part of the building with a water-permeable layer ( mostly gravel, drainage mats, drainage filter socks or other artificial drainage elements ) is surrounded from which the drainage pipes draining water. The drainage layer is protected against the ground by a fleece layer before capping with fine material. To drainage pipes for buildings and structures greater demands than to drainage pipes in agriculture will be provided. They are according to DIN 4095 can withstand a slight overpressure of 0.2 m water column and rigid pipes in the form of bar goods (instead of reel) are required, such as plastic pipes made ​​of PVC (polyvinyl chloride) hard to DIN 1187 Form A or DIN 4262 - 1

The discharge of drainage water into the combined sewer system is not permitted because of the increased hydraulic load on the wastewater treatment plants. The discharge into the storm water system is subject to licensing. Details are governed by the statutes of the local drainage.

Special drainage systems for civil engineering purposes

Drainage pile

When drainage pile the properties of piles and wells are combined. Thus, the load application is a component allows into the ground at the same time farming of groundwater by pumping or injecting.

Filter tube and reinforcement

Finished pile drainage

To prepare a drainage pile is - as in bored pile - first drilled a cased hole and dug the ground intervening. Subsequently, the filter tube is installed (for example, bridge slot tube) together with the pile reinforcement. At the bottom of the pile drainage drainage concrete is introduced as grained concrete ø 4 -8mm. In the rest of the pile is fertigbetoniert with a conventional concrete. The casing is partially pulled up and removed. After curing, the drainage pile may start function both for load transfer as well as for water regulation.

Drainage wall

Similar to a drain pile the principle can also be applied to a trench wall, which thus becomes a drainage wall. For a Verbauart is possible, which is very space saving by combining support and drain function and may be beneficial in cramped spaces.

Drainage wall on one side

View pit with drainage wall

Drainage anchor

For natural slopes, the slope occurring water can be problematic if a break in the slope or excavation is to be made on a slope, because anströmendes slope water creates a water pressure, which can lead to water leakage.

Detailed training head drainage anchor

Detail screen filter mortar of the company Ischebeck

Drainage anchor with a filling of drainage mortar provide a solution for this by collecting and discharge slope water already low before the incision. Thus, a reduction of the pore water pressure is reached and the slope is additionally stabilized. When running is essential that the drainage anchors are rising drilled into the ground so that the water can also be draining pressure to flow through the drain mortar.

It is important that the drainage anchors are rising drilled into the ground so that the water can drain through the drain without pressure mortar.

Such drainage anchors are installed in trenches on a slope, with slope barriers and behind retaining walls to a depth of 14 m in relationships and in a wide variety of soil types - used to advantage - of bed on fine-grained layers to jointed rock. The above example shows an excavation safety in the high mountains with a height of about 20 m and a pit length of about 120 m. The slope water could be collected and carried off with the built-in drainage anchors up to 10 m behind the pit.

Drainage tunnels

Tunnels often cut and water- bearing strata, so that the secure removal of the water pressure and the derivation of the resulting water is important for operational safety. Accumulating usually water is drained in the annular gap between the inner and the outer shell of a tunnel to the base points and the lateral flow there through a filter layer in a drain line. A common problem with this type of drainage of tunnels represents the sintering, whereby deposits affect the water permeability. This restriction has different causes and may be reduced by selection of more suitable geotextiles as a filter in the annular gap through gravel with reduced quantities of cement (less than 200 kg / m³) for the filter layer and drainage lines with larger intake openings.

Drainage on river dikes

The drainage can be a security measure to existing river dikes to counter the increasingly occurred dike breaches, as they occurred after extreme flood discharges in the recent past (Oder flood in 1997, the Elbe flood in 2002, the Elbe flood 2006). Many river dikes in Germany have a long rich history. They usually have to steep slopes and no zoning in poetry, support and drainage core, so that in the future improvement of these dikes is necessary. Floods can cause three different types of dam failures: by overflow through leakage or through sub- streams.

The leakage can be reduced by drainage of the dyke edges on the land side. Depending on the permeability and antecedent soil moisture of the dike body it comes with prolonged impounding - reinforced by non-uniformities, such as loosening areas or animal burrows - vulnerable to moisture penetration, which reduces the grain - to-grain stresses and the stability of the land-side slope by flow forces.

Drainage of landfills

In landfills, the drainage is an important part of the drainage system as quickly as possible derived with the resulting leachate from the landfill and wastewater treatment are supplied. This is intended to impounding prevented in the landfill body and the base gasket to be protected. This drainage system consists of the surface drainage system, the drainage pipes and inspection chambers, if necessary, and / or cleats as well as outlying reservoirs. Details are set out in the Landfill Ordinance ( DepV ), which, in 2009, the previously existing waste TA and TA replaced municipal waste. As a surface drainage system at least 30 cm thick gravel layer of round grain the grain group was 16/32 set. The Kalziumcarbonatanteil should be no more than 20 wt TA waste - be % to prevent encrustations. The drainage lines should therefore have sufficient durability, stability and deformability (to adjust ratios ). The lines should be controllable and washable: this minimum diameter of DN 250 and lines made ​​from HDPE (high -density polyethylene ) are provided.

In the long-term operation of drainage systems of landfills incrustations can occur by precipitation of sparingly soluble compounds that constrict the pipe cross-section. The causes lie in chemical and physical processes that are triggered by changing the pH, the partial pressure of carbon dioxide or oxygen access, and varied in microbiological degradation processes of methanogens and sulfate-reducing bacteria that produce in their immediate environment in an alkaline medium and thus precipitation salts out call.

By appropriate design of the drainage system as low as possible Kalziumcarbonatgehalt in the surface drainage as well as with well-controlled and flushable lines of these operating problems can be prevented.

A special form of drainage of waste landfills is the gas drainage, with the resulting landfill gas is derived. These combined systems have been installed, with which leachate and landfill gas are collected and derived primarily in municipal solid waste landfills. With the end of the deposition of untreated waste such sites are in Germany since 2005 no longer allowed. They are completed since then and enclosed by the outer sealing systems. Also includes a gas drainage, which is areally under the geomembrane, the stormwater holding back. The requirements are set out in the Landfill Ordinance of 2009.

Drainage of sports fields

The areal drainage is often used in lawn and play areas for sports facilities. The goals are similar to the agricultural application: according to rainfall is rapid utilization possible and in irrigation usually required the removal is to be ensured by excess water. Examples: Allianz Arena Munich, Dusseldorf Rhein Stadium

Drainage for agricultural purposes

Objectives

Drainage systems are used in agriculture in order to increase the yield by draining excess soil water. These may be of several reasons:

• Increase productivity by facilitating the management ( Befahrung )
• As a prerequisite for further improvement measures ( land improvement by deep plowing or deep loosening )
• Use change, especially when changing from grassland to arable land,
• Prevention or mitigation of salinization (especially irrigation)

Drainage measures

Drainage measures in the agricultural sector are the purpose and arrangement of the systems differed in:

• Systematic drainage ( drainage arrangement of several parallel lines)
• Bedarfsdränung ( drainage of sinks, outlets of sources and the like ),
• Fangdränung ( acquisition of laterally inflowing groundwater and / or laterally to tretendem, near-surface water).

In the agricultural use of the drainage tube drainage is usually used only in special cases, such as the lack of natural drainage way, bore wells and drainage pumps are used.

Benefits of an Effective drainage system

• If the ground is wet, damaged the soil structure and soil life. By drainage is achieved gare and fertile soils, which are the basis for secure, high yields.
• Waterlogged soils can not be driven or poorly and often delayed. A dräniertes, dry field can be edited for optimal processing date. This lowers the cost of labor and machinery and the plant protection costs.
• The leaching of nutrients is increased to wet soils. By dräniertes field fertilizer costs can be saved.
• Through drained and evenly through rooted soil, the farmer reached uniform field stocks that facilitate inventory management and provide a homogeneous harvest.
• Drained soils can absorb more rain water and reduce soil loss by erosion.

Tube drainage

When the water drainage in perforated conduits ( a technically " sucker " ) is captured and fed to larger lines ( collector ). In both sections of the inflow of water occurs under hydraulic pressure, inasmuch as the term sucker is slightly misleading. The collector flow into ditches and streams ( a technically receiving water ). At the orifice of collectors usually check valves are used on the one hand zurückdrängendes water and the other hand to restrain animals ( therefore also referred to as a frog flap ). As a pipe systems Plastic pipes are most common today, the corrugated exterior (higher load capacity and increased flexibility ) and are smooth on the inside ( improved water runoff, reduced deposits ). The water enters the tubes over narrow slits as inflow apertures, which are for protecting the wave troughs of the outer ribs have a width between 0.6 and 1 mm and a length of 0.6 to 2 mm. These tubes are available with diameters between 50 and 400 mm and are supplied in rolls of up to 300 m in length. The pipes can be surrounded by filter material ( filter drainage hose), to reduce the fine particles from material (especially sound and Schluffanteile ) to reduce the resistance at the inlet openings and to protect the tubes from mechanical pressure.

Drainage laying on a pasture

Drainage pipes " on-call"

Drainage pipe - closeup

Drainage pipe with filter casing

Laying machine in use

Design of drainage systems

In the technical design of drainage systems, the spatial conditions with the extent and altitude of the areas to be considered as drainage geometry. The properties of the soil will be measured through the water conductivity of the soil layers, divided into saturated and partially saturated hydraulic conductivity ( characteristic flow length per unit of time, usually m / s). In addition, the depth of the pipes and the water table. The exact mathematical determination is connected with the solution of differential equations, which is correspondingly expensive. For the design of drainage systems, the use of use formulas in addition to the use of computer programs is common, such as the calculation approach of Hooghoud in which the aforementioned relevant factors lead to a design water runoff, which allows the selection of the pipe cross section.

Installation of drainage pipes

The drainage pipes made of flexible plastic pipes are laid for decades with special machines which mostly with trenchless drainage plow a narrow slot pull in the ground and insert the pipe through an arcuate guide in the low 0.8 to 1 m. Less common are grave milling in use that dig a narrow trench with a revolving chain and milling system, in which the tube is inserted. For large height differences, it may be necessary especially for drainage collector to transfer them in greater depth, including dredging operations will be required.

Melioration by mole plow

In this Drainung a narrow plow is pulled through the soil, at the lower end of a press head is pulling a tube remaining in the ground. This method is pictorially described as Maulwurfsdrainung and can be used in cohesive, sufficiently plastic soils. The depth of these tubes is about 60 cm, the distance between them of about 2 m.

History of the drainage of agricultural land

Drainage of agricultural land are known from antiquity. In excavations by the common traditions Steindränungen could be detected. From 1650 drainage systems are covered with wood and stone pipes from England. Shortly after this technique was also used in Germany. More extensive drainage measures under the concept of melioration were started in Germany in the 19th century. These activities have been analyzed for areas in the Prussian provinces of Westphalia and Brandenburg 1830-1880 comprising part of a dissertation and described. The starting point was structural reforms, in which the only extensively used so far and usable commons were opened for private investment, including triggered by the price increases according to the agricultural crisis of the 1820s. For the enforcement of this large-scale land reclamation is a three-phase flow model has been found, at the beginning of the agricultural reforms were, which was followed by an " incentive system " with clubs, agricultural schools, model farms and bonuses. In the third phase, large centrally planned and directed Landesmeliorationen with extensive financial resources and new legal foundations could be implemented.

Implementation of the measures could be ascertained from the documents in detail, these include the environmental impacts with a radical change in the regional hydrology through irrigation and drainage measures as well as the disappearance of formerly extensively used landscapes, such as moorland and heathland. Drainage is a strong intervention in the ecosystem, as is lowered more or less large area by the draining of the water table and changed the vegetation. Thus, for example wetlands and salt locations harboring rare species and have a high biodiversity, are destroyed by draining.

In 1840, the first clay pipes were developed and installed by hand. These clay pipes were further developed until the 1960s and moved mechanically since the 1940s.

In the 1960s, the use of plastic pipes began primarily of inexpensive PVC pipes, which initially had been sawed longitudinal slots were then prepared with wavy walls and punched openings.

The construction of drainage systems in the agricultural sector has declined significantly in Germany since the 1980s, but has continuing importance in the countries increase their agricultural productivity, particularly in the use of irrigation systems or change of use of agricultural land. Surveys in the late 1990s assume that approximately eleven percent of the agricultural land in Germany are equipped with drainage systems. In Austria, the proportion is about seven percent and Switzerland about eight percent.