Drainage is an extensive system of canals - a drain, an artificially created drainage system. The work of specialists is necessary for the design of any types of drainages, because... includes preparing data for technical solutions. Installation of engineering systems on the site, installation of sewerage equipment, electrical installations are planned together with drainage work. Any types of drainage used on the site directly depend on hydraulic conditions. Properly arranged drainage significantly covers all costs associated with its installation.
Drainage of a garden plot is necessary when groundwater is close to the ground. The purpose of such drainage is drainage to maintain the cultivated land surface in normal condition.
Types of garden drainage can be open or closed, which is decided in accordance with the conditions of use. An open type of drainage consists of interconnected channels in crushed stone, located at a distance from each other. This open-type drainage system does not decorate the site and requires additional fencing and annual cleaning.
Closed drainage
A closed type of drainage is a more effective and efficient method. This is a technologically sophisticated system of hermetically sealed drainage pipes laid in trenches in a sand-crushed stone layer. The closed type of drainage involves the installation of a manhole and a sump for maintenance, which functionally regulate the entire drainage system. A closed type of drainage is used to lower the general groundwater level in the area.
Drained soil is easier to cultivate, preparing for sowing and fertilizing. With the installation of a drainage system on the site, soil waterlogging is eliminated. Considering that combining types of drainage system gives the best results, they are often used together. A combined type of drainage is used for comprehensive protection of areas adjacent to the house. The combination of hidden underground drainage with surface drainage is as functional as possible.
According to the method of location, types of drainage differ into horizontal and vertical drainage.
Horizontal drainage- These are buried tubular drains for installing open drainage over large areas. Closed horizontal drainage is a type of drainage used in suburban construction.
The construction of a closed drainage system involves a 30cm wide trench laid to a depth of 0.7 to 1.5m so that the slope of the natural drainage is towards the drainage well. For a closed type of drainage, crushed stone is poured onto the bottom of the trench and perforated drainage pipes wrapped in geotextile are laid. If there is a water-bearing layer, the structure is covered with soil and covered with a turf layer. A closed drainage system collects water, directing it to a water intake or a special well.
Any type of closed drainage actively fights not only flooding, but also soil freezing, and therefore the consequences of these destructive processes. The deep drainage system is used when groundwater is deep up to 10 meters. Like all types of drainage, a deep drainage system is planned and calculated in advance, during the initial development of the site. Deep drainage is necessary in most of central Russia, in all cases of low-lying site location. In deep drainage, a main drain is usually used to collect water from adjacent side drains to be carried off-site or into a drainage well. Deep drainage is the only way to combat excess groundwater on your site.
Foundation drainage
Foundation drainage is a special type of drainage system. Foundation drainage serves to protect suburban buildings from groundwater. The simplest device for this type of drainage is trench drainage, which is effectively used in the absence of a basement floor. Trench drainage is installed at a distance of 1.5-3 m around the perimeter from the foundation of the building. The depth of the trench should exceed the lowest point of the foundation itself by an average of 50 cm. When installing trench drainage, a protective layer of clay is located between the trench and the foundation, and drainage pipes of the appropriate diameter are laid at the bottom of the trench. The purpose of trench drainage is to protect the building and foundation from deformation.
Wall drainage
Wall drainage is planned if the building has basements, basements, and cellars. The installation of such drainage is necessary in clay and loamy soils. In addition to wall drainage, filter devices and polymer roll materials are used. When designing wall drainage, drainage pipes are laid along the contour from the outside of the building and the walls themselves are protected using wall drainage material.
The foundation drainage system uses linear drainage for surface drainage. This type of drainage is used for arranging open areas in front of a country house, sidewalks and adjacent areas. Linear drainage serves to preserve road surfaces and protects the foundation and basement floors from destruction. This is a collection of underground channels and ground-based protected grids. Linear drainage collects water to be discharged into the storm drain.
Point drainage
As additional protection for linear drainage of the foundation, point drainage is installed. Point drainage is installed in small areas, at entrances and exits, under drainpipes to quickly remove excess water. The rain inlets installed in this case are covered on top with a mesh cast iron, steel or plastic grate. The combination of linear surface and underground foundation drainage gives the best soil drainage results.
The functional variety of drainage types helps to properly arrange the drainage system in a specific case on your site. Provide your suburban area with a reliable drainage system.
Price for
5.1. When constructing a closed horizontal drainage, the requirements of SNiP III-8-76, SNiP III-16-80, SNiP 3.05.04-85 and this section must be met.
5.2. Construction of drainage should be carried out starting from higher-order collectors to drains. The development of the trench and the laying of drainage pipes should be done from the mouth to the source (from bottom to top).
5.3. When laying a drainage system in an area with a transverse slope of more than 0.03 and the presence of uneven surfaces with a height of more than 20 cm, the surface of the collector and drain routes must be leveled on a strip 4 m wide.
5.4. When constructing closed horizontal drainage, as a rule, trench and trenchless drain pavers equipped with laser slope indicator systems should be used.
Single-bucket excavators for making trenches may be used in the following cases:
when the depth of the trench and the diameter of the laid drainage pipes exceed the technical capabilities of the drainlayers;
when the soil group is higher than the permissible level for the difficulty of development and when the soil contains inclusions that impede the operation of the drainage machine based on multi-bucket excavators;
when installing drainage in soils with a bearing capacity that does not allow the movement and operation of drainage machines;
when laying drainage pipes on shelves and racks.
5.5. At sites with different geological and hydrogeological conditions, it is necessary to provide for the joint operation of continuous machines and single-bucket excavators.
5.6. Laying drainage pipes in water or on liquefied soil is prohibited.
5.7. In winter, when the depth of soil freezing exceeds the technical capabilities of drain layers based on multi-bucket excavators, the layer of frozen soil must first be loosened.
5.8. Backfilling of drainage trenches should be carried out in two stages: backfilling of drains and final backfilling.
The filling of drains must be done mechanically immediately after laying the pipes. Stones with a diameter of more than 5 cm and lumps of frozen soil with a diameter of more than 10 cm are not allowed in the powder material.
The final filling of drainage trenches with a bulldozer should be carried out while it is moving along the axis of the trench or at an angle of no more than 30°.
Backfilling should be done in the direction from the source to the mouth.
5.9. Backfilling of the trench in stable soils must be carried out no later than three days from the date of laying the drainage pipes; in quicksand soils, as well as in winter conditions, regardless of the type of soil, directly after their installation.
5.10. After laying the drains using a trenchless drain layer, the gap should be sealed.
5.11. Drainage mouths and wells must be installed simultaneously with the laying of drainage pipes.
5.12. During operational quality control of the work performed, the following should be checked for compliance with the project and the requirements of these rules:
position of the drain axis;
thickness of cutting the fertile soil layer (when developing a trench with a single-bucket excavator);
slope of the drainage trench;
pit mark for deepening the working body of a trenchless drain paver;
diameter of drainage pipes and their protection with filter material;
slope of plastic pipes laid with a trenchless drain layer;
type of soil powder and its thickness;
backfilling of the trench and restoration of the fertile soil layer (when developing trenches with single-bucket excavators);
closing the gap;
type, completeness and dimensions of drainage structures on the drainage network.
5.13. Deviations of drainage parameters from the design ones should not exceed the values indicated in the table. 5.
Table 5
|
Name |
Permissible deviation |
|
Collector and drain axes | |
|
Trench bottom mark for pipes with diameter, mm: | |
|
from 75 to 125 | |
|
„150 „ 250 | |
|
Marking the head of the collector or drain | |
|
Longitudinal slope on sections 100 m long |
± 0,0005 |
|
Lateral displacement of ceramic pipes at joints |
1/3 pipe wall thickness |
|
Powder layer thickness | |
|
Drain length | |
|
Note. The lateral displacement of ceramic pipes is checked when laying in a non-mechanized way. |
|
5.14. Slope-free sections are allowed for a length of no more than 10 m, subject to the general slope. Areas with a reverse slope of the trench bottom, a decrease in the thickness of the protective filter material and an increase in the gap at the joints of the drainage pipes are not emitted.
5.15. Checking the marks of the bottom of the trench or the top of laid drainage pipes should be done: for drainage slopes up to 0.005 - after 3 m, for large slopes - after 5 m; when laying drainage pipes using a trenchless drain layer - every 5 m, regardless of the slope.
Most owners of private houses and summer cottages are interested in types of drainage. Drainage systems are widely branched, interconnected networks of canals running around or along a building. They protect the building, and, if necessary, the entire area on which it is located, from the negative influence of surface and groundwater, removing excess moisture outside the drained area. This solution allows you to drain water that accumulates on the site, which is especially important in winter, when moisture expands in volume due to low temperatures.
The most suitable type of drainage system should be selected at the planning stage in order to give the building the opportunity to survive longer without visible damage. Moreover, a well-made drainage system will help simplify the process of growing plants on the site, always delivering them enough water.
Types of drainage systems
When choosing the most suitable type of drainage for your project, you should first understand their classification. According to the type of placement, the types of drainage systems differ in:
- superficial;
- underground.
The former are also called open, and the latter - closed. The essence of the surface system is the simplicity of its construction: small ditches are made on the surface that deliver water to the desired point. The main disadvantages of this system are rapid wear and tear and not a very aesthetic appearance.
Underground drainage is a system of pipes laid underground. It does not spoil the appearance of the site and lasts longer, but the construction of such a system costs a lot of effort and expense. There are also other options, such as horizontal and vertical drainages. They are used less frequently than those listed earlier, but there are cases when they are necessary. Let us dwell in more detail on open and closed drainages.
Open drainage system
The open (surface) option involves draining water from the surface of the site and the roofs of buildings.
Storm flow is diverted from the site, thus preserving the foundation, basements and other underground structures from damage. To install such drainage, it is enough to dig a trench around the building; subsequently, it will be the one that will receive water flows. Usually the system is covered with gratings to give it a more aesthetic appearance. The surface system is divided into the following types of drainage:
- linear;
- spot.
The linear type requires significant effort during construction, since the construction of channels takes into account the slope of the site and the walls of the buildings. Particular attention is paid to garage entrances, especially if they are below ground level. This drainage is done using ducts that are dug in the ground. To prevent the soil from being washed away by water flows, the inner surface of the channels is filled with concrete.
Point drainage is used to collect water at drainage points; the channels are closed with decorative gratings. In addition to improving the appearance of the system, this prevents large debris from entering the system, which can reduce the efficiency of the drain. The water most often drains into the nearest lake or river.
As mentioned earlier, this system is quite simple to implement and does not require professional knowledge and skills during construction. The biggest difficulty in constructing drainage devices is maintaining the slope of the water pipelines so that the water itself flows to the selected drainage location.
A deep (closed) drainage system is used if necessary, for example, when the site is located in a lowland or on soil with a clay structure. This type of drainage is also called tubular, since pipes are installed in the trenches, which have open areas that collect water.
The construction of such systems is a rather complex process. First of all, trenches are dug 40 cm wide than the diameter of the pipes used. The depth depends on the groundwater level. The bottom of the trench is covered with a layer of sand, and a layer of crushed stone is placed on it. The thickness of the permeable layers should therefore be 20 cm. Pipes are laid on top of the crushed stone, which should be wrapped in geotextile fabric.
This way, sand will not get inside the pipes, clogging them. Next, a layer of sand and crushed stone is poured over the pipe, the system is completely covered with soil, on which the turf is laid. It must be borne in mind that the pipes must be installed with a slight slope directed towards the water collection point. Inspection wells should be installed at pipe bends.
Horizontal and vertical systems
In some cases, open and closed types of drains are not suitable for drainage devices. Then other types of drainage are used: horizontal and vertical.
The horizontal type of drainage on the site includes both the construction of ditches and trays, and the construction of backfill structures. Typically, such a system is used on private plots, but is also used in urban construction. The main task of horizontal drainage is to preserve the foundation, but it also copes with moisture in basements. Thus, the ring type of horizontal drainage is based on a decrease in the level of soil water. To achieve this, pipes are laid within 6-8 meters from the walls of the protected structures at a depth of 50 cm below the floor of the building.
Vertical type drainage is mainly used to drain water in a well. This is achieved by using pumps connected to pipes. After pumping out water, depression funnels form near the wells. As long as water flows into them, the surrounding area is protected from water. This type of drainage allows you to effectively remove moisture from deep layers of soil, thereby significantly lowering the groundwater level in the area.
A drainage system on a site outside the city is a mandatory element, since sewerage and water supply here are often autonomous. Well, what type of drainage devices to choose depends on individual capabilities and preferences.
The distance between drains and dryers is determined by the Rothe formula:
where L is the distance between dryer drains, m;
H - height of unreduced groundwater level, m;
S– required reduction in groundwater level, m;
k
p
Rice. 2.4. Calculation diagram of perfect systematic drainage.
Table 2.2.
Soil filtration coefficient
Table 2.3.
Soil infiltration coefficient
2.2. Calculation of imperfect horizontal drainage.
When the aquifer is more than 5 m deep, imperfect systematic drainage is laid in the aquifer (at a depth of 3.5 m)
Rice. 2.5. Calculation scheme of imperfect systematic drainage.
The distance between adjacent drains of imperfect drainage is determined by the formula S.F. Averyanova:
Where T– distance from the center of the drain to the aquitard, m;
h 1 – highest point of the depression curve, m;
k– soil filtration coefficient, m/day, table. 2.2;
p– coefficient of precipitation infiltration into soil, m/day, table. 2.3.
Value B is calculated according to the dependence
Where r– drain radius, m, (we accept drains with a diameter of 0.2 m)
Laying of drainage pipes occurs according to a pre-developed drainage system plan. The minimum slope of the drainage pipe according to the building code is 0.002 in clay soils, and 0.003 in sandy soils. In practice, for normal water flow, the pipe slope is 0.005 - 0.01. On the ground, dryer drains are located in such a way that the pipe runs in the ground parallel to the terrain and, accordingly, the depth of the dryer drain does not change throughout its entire length.
The drains are covered with several layers of permeable materials (for example, geotextiles) - first, washed crushed stone or gravel is placed, then sand, and the previously excavated soil is placed on top. The thickness of the fills ranges on average from 100 to 300 mm (the less permeable the surrounding soil, the thicker the fill). To prevent siltation of drains and clogging of perforations, filters made of geotextiles (for reclamation of sandy and sandy loam soil) or coconut fiber (if clay, loam, and peat bogs are drained) are used.
Exercise.
Calculate the distance between drainage drains of perfect and imperfect drainage, construct the corresponding calculation diagrams. Select the source data from the table. 2.4.
Table 2.4.
Initial data.
| Option | ||||||||||
| Depth to aquitard: perfect imperfect | 3,75 5,8 | 3,5 6,5 | 3,8 7,2 | 4,0 7,6 | 4,2 6,8 | 4,5 5,5 | 3,7 6,3 | 3,9 7,4 | 4,1 9,1 | 4,3 7,1 |
| Soil type | ||||||||||
| Ground water level | 0,4 | 0,9 | 0,8 | 1,1 | 0,5 | 0,6 | 0,4 | 1,2 | 0,7 | 1,3 |
| Dehumidification rate | 2,0 | 2,0 | 2,0 | 2,5 | 2,5 | 2,5 | 2,0 | 2,5 | 2,5 | 2,5 |
Note: soil type 1 – loam, 2 – sandy loam, 3 – medium sand
Practical work 3.
Scheme of the vertical layout of the village ensuring drainage and normal movement of vehicles and pedestrians.
The vertical layout scheme is developed based on the materials of the geodetic base and the general plan of the village (city).
At this stage of designing a vertical layout, the main, expedient decisions are determined on the general high-rise arrangement of all elements of the city, on the organization of surface runoff and measures for the improvement of territories unfavorable for development. The scale of the diagram is 1:2000 – horizontal and 1:200 – vertical.
When developing a vertical layout scheme, design (red) marks are determined at the points of intersection of street axes at intersections and at places where the relief changes along the street route and the street route itself.
Black marks are determined from the topographic plan by interpolation between horizontal lines. The distance between the marks is taken according to the plan in accordance with the scale. Then, between intersections, the compliance of the longitudinal slope of the street with the permissible minimum and maximum slopes is checked and the design longitudinal slope is determined using the formula:
i– longitudinal slope;
h– excess of marks between intersections, m;
L– distance between intersections, m.
Permissible longitudinal slopes are accepted as –5‰-80‰.
On the vertical layout diagram at intersections at the intersections of the axes of roadways or slope breaks, existing and design marks are made: the arrow shows the direction of the street slope, the longitudinal slope is noted above the arrow, and below it is the distance between the intersections of the street axes.
The following procedure can be recommended for final coordination of the planning solution with the relief and clarification of the actual high-rise organization of the village.
1. The general layout design is applied to the geodetic plan. The streets along which it is proposed to design longitudinal profiles are numbered and along their axes the marks of the existing relief at their intersections and at turns are calculated (by interpolation between horizontal lines) (Fig. 2).
2. Longitudinal profiles are drawn up along the axes of the planned main streets, according to the horizontal plan. In the conditions of existing populated areas, where, in accordance with the rules of surveying and drawing up geodetic plans, the relief within the street is not shown, the following methods can be used to compile their longitudinal profiles: if the general character of the street does not differ from the relief of the surrounding territory or differs slightly from it, longitudinal profiles are drawn up on the basis of a horizontal plan, and on the territory of streets the latter are carried out conditionally, in relation to the topography of adjacent territories.
If an existing street runs in conditions that differ sharply from the topography of the adjacent blocks (in a cut or along an embankment), it becomes necessary to use leveling profiles. In most cases, such profiles are available in cities for almost all significant streets, usually at scales from 1:2000 to 1:500.
Rice. 3.1. Numbering of streets and calculation of axis marks.
The existing leveling profiles, in relation to the scale of the design solution, must be redrawn on a scale of 1:5000. In order not to equip them with unnecessary marks, you should not transfer all marks from a large scale, but you need to select only the main points that characterize the relief of the longitudinal profiles of streets.
In this case, in addition to longitudinal profiles, it is desirable to have cross-sections taken every 200-300 m. When designing, cross-sections will allow one to judge the height ratio of the street to the adjacent territory and, accordingly, the most advantageous height solution for the longitudinal profile. It should be noted that leveled longitudinal profiles of streets are also necessary when drawing up a vertical planning scheme in cities with very poorly defined relief. In this case, the leveled longitudinal profile of the existing street makes it possible to judge its microrelief and, accordingly, facilitates the task of choosing the direction of drainage.
3. The choice of one of the above methods and the identification of either the need to use leveling profiles, or the possibility of doing without them, can be made on the basis of a detailed examination of questionable areas in situ and a careful study of the geodetic plan. If, during a reconnaissance survey, existing streets with particularly complex terrain are identified, the horizontal profile of which cannot be drawn up, and there is no ready-made leveling profile, attention should be paid to leveling. Based on the horizontal plan, and, if necessary, on the basis of leveling profiles, approximate directions of slopes and the direction of drainage along the streets are outlined (Fig. 3).
4. Longitudinal profiles of streets are designed, a design line is drawn, design marks are written out at intersection points, changes in slopes and in places of significant earthwork (more than 0.50 m), design slopes and distances are written out. The degree of detail of the profile design solution is determined by the scale; namely: the design line is drawn only as a first approximation, while slopes of similar magnitude are generalized, insertions when connecting slopes of different directions are not designed at all or are outlined in the most general form.
Rice. 3.3. Applying the design solution to the plan.
5. The final design solution (slopes, distances, marks) is transferred from the profiles to the plan, design marks are written out at the points where the profile breaks and the axes intersect. In sections of overpasses and bridges, due to the impossibility of graphically putting the height solution on the plan in full, design data is shown only in the approach areas.
6. In conditions of complex terrain (flat or with steep slopes), in addition to the profiles along the main highways, a plan solution is given for secondary streets, which more fully illuminates the drainage conditions and the high-rise solution for the city as a whole. The same elements are written out on the plan: slopes, distances, red and black marks in places where slopes change. When graphically designing a drawing, you should show with various symbols the solutions carried out according to the profiles and according to the plan (Fig. 4).
7. The contours of areas requiring significant backfilling or cutting are identified. The volumes of continuous earthworks are calculated in areas where overpasses, bridges and approaches to them are built on dams, in sections of streets where the average height of excavation or embankment exceeds 0.5 m, etc. In addition, the amount of land that will be obtained is calculated from the pits of permanent buildings with basements. For individual elements, the calculation of earthworks is carried out as follows: on sections of streets where working marks exceed 0.5 m, the calculation is made according to longitudinal profiles; in areas of continuous backfilling or cutting with working marks of more than 0.5 m, the calculation is made using the square method. The volume of land from building pits is calculated by multiplying the area occupied by capital construction by the average pit depth. The capital development area is taken according to the general planning project (percentage of development). Based on the calculation of volumes for individual elements, an earthworks list is compiled.
Exercise.
Develop a scheme for the vertical layout of the settlement to ensure drainage, normal traffic and pedestrian traffic. The settlement plan should be adopted in accordance with the option according to app. 1.
Practical work 4.
The drainage system is a system of drainage pipes that can be located around or along the house, as well as on a separate part of the land. It is designed to collect and drain excess water from the ground, preventing flooding.
It is worth noting that there are quite a few varieties of this system - each of them is used in certain cases. That is why it is worth considering the types of drainage in more detail.
Drainage system at your dacha
Surface drainage
A system of this type serves to accumulate and drain rain and melt water from the site, preventing its flooding if the soil permeability is poor.
There are two types of surface drainage: point and linear.
In the first case, water collectors are installed locally; water flowing from the roof or irrigation taps is supplied here.
Linear drainage covers a larger area, collecting water over its entire area.
This is what surface drainage looks like
As for the design features, let's consider them using the example of one surface drainage ditch.
It has a depth of about 25-35 cm, V-shaped or trapezoidal in shape. That is, the walls of the ditch are at a slope of approximately 30-40 degrees.
It is also important to maintain the slope of the ditch to ensure natural flow of water. It is 1 cm per 1 meter of its length.
Ditch for drainage
Deep drainage
Already from the name itself you can understand that with deep drainage, all communications are located deep under the surface of the earth.
This makes them highly efficient and allows them to drain not only rainwater, but also groundwater.
This is what deep drainage looks like
Let's consider the main types of deep drainages. There are only two of them:
- horizontal;
- vertical.
Each of them has its own characteristics and must be considered separately.
Horizontal drainage
They are horizontal drainage systems; they help reduce the groundwater level, which can rise significantly during snow melting or heavy precipitation.
Such drainage is most often installed in areas located in lowlands, as well as in areas where there is excess moisture.
Deep horizontal drainage
If we consider the design features of such drainage, then it is a network of deep trenches (1.8-1.5 meters), in which there is a layer of drainage made of sand and crushed stone, and drainage pipes (drains) are laid on top.
They differ from ordinary sewer ones by the presence of a large number of holes with a diameter of 1-1.5 mm.
All these pipes lead to a single drainage well.
The functions of such drainage are as follows:
This type of drainage is used by owners of private land plots much more often than others.
Vertical drainage
It is a system of wells located in the required quantity on a plot of land.
They are usually placed near buildings, effectively draining the collected water. For drainage, special pumps and pumps are used.
In some cases, trenches are constructed that allow water to move independently without the use of special equipment.
This is what a vertical drainage system looks like
It is worth noting that vertical drainage is very effective.
But, over time, it begins to silt, losing its productivity.
Then it is necessary to perform maintenance on the system in order to restore its functionality.
This is what a drainage well looks like (vertical drainage)
Due to the rather high complexity of the construction work, a vertical drainage diagram must be drawn up before it begins.
It is better to trust the work to specialists.
It shows the placement of wells or boreholes on the site, and also gives the following information.