Stairs. Entry group. Materials. Doors. Locks. Design

Works in this cycle include:

■ construction of upland and drainage ditches, embankment;

■ open and closed drainage;

■ surface planning of warehouse and assembly areas.

Surface and groundwater are formed from precipitation (storm and melt water). There are “foreign” surface waters, coming from elevated neighboring areas, and “our own”, formed directly at the construction site. Depending on the specific hydrogeological conditions, drainage work surface waters and drainage of soils can be carried out in the following ways: open drainage, open and closed drainage and deep dewatering.

Upland and drainage ditches or embankments are arranged along the borders construction site on the mountain side to protect against surface water. The site area must be protected from the influx of “alien” surface water, for which purpose it is intercepted and diverted off site. To intercept water, upland and drainage ditches are installed in its elevated part (Fig. 3.5). Drainage ditches must ensure the passage of storm and melt water to low points in the area beyond the construction site.

Rice. 3.5. Protection of the construction site from the influx of surface water: 1 - water drainage zone, 2 - upland ditch; 3 - construction site

Depending on the planned water flow, drainage ditches are installed with a depth of at least 0.5 m, a width of 0.5...0.6 m, with an edge height above the design water level of at least 0.1...0.2 m. To protect the ditch tray from erosion, the speed of water movement should not exceed 0.5...0.6 m/s for sand, and -1.2...1.4 m/s for loam. The ditch is installed at a distance of at least 5 m from the permanent excavation and 3 m from the temporary one. To protect against possible siltation, the longitudinal profile of the drainage ditch is made at least 0.002. The walls and bottom of the ditch are protected with turf, stones, and fascines.

“Own” surface water is drained by giving an appropriate slope during the vertical layout of the site and installing a network of open or closed drainage, as well as by forced discharge through drainage pipelines using electric pumps.

Drainage systems open and closed types used when the site is heavily flooded with groundwater with high level horizon. Drainage systems are designed to improve general sanitary and construction conditions and provide for a reduction in the level groundwater.

Open drainage is used in soils with a low filtration coefficient when it is necessary to lower the groundwater level to a small depth - about 0.3...0.4 m. Drainage is arranged in the form of ditches 0.5...0.7 m deep, to the bottom which a layer of coarse sand, gravel or crushed stone 10...15 cm thick is laid.

Closed drainage is usually deep trenches (Fig. 3.6) with the construction of wells for system revision and with a slope towards water discharge, filled with drainage material (crushed stone, gravel, coarse sand). The top of the drainage ditch is covered with local soil.

Rice. 3.6. Closed, wall and encircling drainage: a - general drainage solution; b - wall drainage; c - ring enclosing drainage; 1 - local soil; 2 - fine-grained sand; 3 - coarse sand; 4 - gravel; 5 - drainage perforated pipe; 6 - compacted layer of local soil; 7 - bottom of the pit; 8 - drainage slot; 9 - tubular drainage; 10 - building; eleven -retaining wall; 12 - concrete base

When installing more efficient drainages, pipes perforated in the side surfaces are laid at the bottom of such a trench - ceramic, concrete, asbestos-cement with a diameter of 125...300 mm, sometimes just trays. The pipe gaps are not sealed; the pipes are covered on top with well-draining material. The depth of the drainage ditch is 1.5...2.0 m, the width at the top is 0.8...1.0 m. A crushed stone base up to 0.3 m thick is often laid underneath the pipe. Recommended distribution of soil layers: 1) drainage pipe, laid in a layer of gravel; 2) a layer of coarse sand; 3) a layer of medium or fine-grained sand, all layers at least 40 cm; 4) local soil up to 30 cm thick.

Such drainages collect water from adjacent soil layers and drain water better, since the speed of water movement in the pipes is higher than in the drainage material. Closed drainages are installed below the soil freezing level; they must have a longitudinal slope of at least 0.5%. Drainage installation must be carried out before the construction of buildings and structures begins.

For tubular drains in last years Pipe filters made of porous concrete and expanded clay glass are widely used. The use of pipe filters significantly reduces labor costs and the cost of work. They are pipes with a diameter of 100 and 150 mm with big amount through holes (pores) in the wall through which water seeps into the pipeline and is discharged. The design of the pipes allows them to be laid on a pre-leveled base using pipe layers.

LECTURE 3

DISCHARGE OF SURFACE (ATMOSPHERE) WATER

The organization of surface rain and melt water runoff in residential areas, microdistricts and neighborhoods is carried out using an open or closed drainage system.

On city streets in residential areas, drainage is usually carried out using a closed system, i.e. city ​​drainage network ( storm sewer). The installation of drainage networks is a citywide event.

In the territories of microdistricts and neighborhoods, drainage is carried out by an open system and consists of organizing the flow of surface water from building sites and sites for various purposes and areas of green spaces into driveway trays, through which water is directed to the driveway trays of adjacent city streets. This organization of drainage is carried out using a vertical layout of the entire territory, ensuring drainage created by longitudinal and transverse slopes on all driveways, sites and territories of a microdistrict or block.

If the network of passages does not represent a system of interconnected passages or if the capacity of the trays on the driveways is insufficient during heavy rainfall, a more or less developed network of open trays, ditches and ditches is envisaged in the territory of the microdistricts.

An open drainage system is the simplest system, which does not require complex and expensive structures. In operation, this system requires constant supervision and cleaning.

The open system is used in microdistricts and neighborhoods relatively small area with a terrain favorable for water flow, without low drainage areas. In large microdistricts, an open system does not always provide surface water drainage without overflowing trays and flooding driveways, so a closed system is then used.

A closed drainage system provides for the development of an underground network of drainage pipes - collectors - on the territory of the microdistrict, with the reception of surface water by water intake wells and the direction of the collected water into the city drainage network.

As possible option a combined system is used when an open network of trays, ditches and ditches is created on the territory of the microdistrict, supplemented by an underground network of drainage collectors. Underground drainage is very important element engineering improvement of residential areas and microdistricts, it meets the high requirements of comfort and general improvement of residential areas.

Surface drainage on the territory of the microdistrict must be ensured to such an extent that from any point in the territory the flow of water can easily reach the trays of the roadway of adjacent streets.

As a rule, water is diverted from buildings towards driveways, and when green spaces are adjacent, to trays or ditches running along the buildings.

On dead-end driveways, when the longitudinal slope is directed towards the dead end, drainless places are formed, from which water has no outlet; Sometimes such points appear on driveways. Water is released from such places using overflow trays, in the direction of passages located at lower elevations (Fig. 3.1).

Trays are also used to drain surface water from buildings and sites for various purposes, in green areas.

Overflow trays can be triangular, rectangular or trapezoidal in shape. The slopes of the trays are taken depending on the soil and the method of strengthening them in the range of 1:1 to 1:1.5. The depth of the tray is not less, and most often not more than 15-20 cm. The longitudinal slope of the tray is taken to be at least 0.5%.

Earthen trays are unstable, they are easily washed away by rain, and they lose their shape and longitudinal slope. Therefore, it is most advisable to use trays with reinforced walls or prefabricated ones made of some stable material.

When there is a significant flow of water, the trays turn out to be insufficient across their entire capacity and are replaced with ditches. Typically, ditches have a trapezoidal shape with a bottom width of at least 0.4 m and a depth of 0.5 m; the side slopes have a steepness of 1:1.5. Strengthen the slopes with concrete, paving or turf. With significant sizes, at a depth of 0.7-0.8 m or more, ditches turn into ditches.

It should be borne in mind that ditches and ditches at intersections with driveways and sidewalks must be enclosed in pipes or bridges must be built over them. It is difficult and difficult to release water from ditches and ditches into driveway trays due to different depths and differences in elevations.

Therefore, the use of open ditches and ditches is permissible only in exceptional cases, especially since ditches and ditches generally disrupt the amenities of modern neighborhoods. Trays, with their usually shallow depth, are acceptable if they do not create great inconvenience for movement.

With relatively small areas of green space, drainage can be successfully carried out open method along the trays of paths and alleys.

When paths and driveways are located among green spaces over a relatively short distance, surface water flow can be carried out without installing trays or ditches, directly onto planting areas. In such cases, fencing with edges for paths and driveways is not suitable. In this case, the formation of stagnant waters and swamps must be excluded. Such runoff is especially appropriate when it is necessary to artificially irrigate green areas.

When designing an underground drainage network Special attention it is necessary to pay attention to the drainage of surface water from main roads and pedestrian alleys, as well as from places where visitors gather (main squares of the park; squares in front of theaters, restaurants, etc.).

In places where surface water is discharged from the territory of microdistricts onto city streets, a water intake well is installed behind the red line, and its waste branch is connected to the collector of the city drainage network.

At closed system drainage system, surface water is directed to the water intake wells of the drainage network and enters them through water intake grates.

Water intake wells on the territory of microdistricts are located in all low points that do not have free flow, on straight sections of driveways, depending on the longitudinal slope, with an interval of 50-100 m, at intersections of driveways on the side of the water inflow.

The slope of drainage branches is taken to be at least 0.5%, but optimal slope is 1-2%. The diameter of drainage branches is taken to be at least 200 mm.

The routes of drainage collectors in the microdistrict are laid mainly outside of passages in strips of green spaces at a distance of 1-1.5 m from the curb or roadway.

The depth of the drainage network collectors in the microdistrict is taken taking into account the depth of soil freezing.

Water intake wells have water intake grates, mainly rectangular shape. These wells are constructed from prefabricated concrete and reinforced concrete elements and only in their absence - from brick (Fig. 3.2).

Inspection wells are constructed according to standard projects from prefabricated elements.

When choosing a drainage system in a microdistrict, it should be borne in mind that in modern well-maintained microdistricts, the development of a network of drainage collectors is predetermined not only by the collection and disposal of surface water, but also by the use of the drainage network for other purposes, such as, for example, for receiving and discharging water from snow melters and when dumping snow into network collectors, as well as when discharging water into the network when washing roadways and driveways.

It is advisable to install an underground drainage network in the microdistrict when equipping buildings internal drains, as well as with a system for removing water from the roofs of buildings through external pipes with water discharge into an underground drainage network.

In both of these cases, the flow of water from drainpipes along sidewalks and areas adjacent to buildings is eliminated, and the appearance buildings. Based on these considerations, it is considered advisable to develop an underground drainage network in microdistricts.

An underground drainage network in microdistricts is also justified if there are drainage-free places on the territory that do not have a free outlet for rain and melt water collected in them. Such cases are relatively rare, but are possible with complex, rugged terrain and cannot be eliminated by vertical planning due to the large volumes of excavation work.

It is almost always necessary to construct an underground drainage network when the microdistrict is deep and the watershed is 150-200 m away from the nearest adjacent street, as well as in all cases when throughput there are not enough trays on the driveways and the driveways can be flooded during relatively heavy rains; the use of ditches and ditches in residential areas is highly undesirable.

When planning vertically and creating surface water flow, the location of individual buildings relative to the natural topography is very important. For example, it is unacceptable to place buildings across the natural thalweg, thereby creating drainless areas.

Avoiding unnecessary and unjustified excavation work on bedding in places without drainage is possible only by draining water from such places using an underground collector of the drainage network, installing a water intake well at a low point. However, the direction of the longitudinal slope of such a reservoir will be opposite to the topography. This may lead to the need for excessive deepening of some sections of the district's drainage network.

Unsuccessful examples include the arrangement of buildings of various configurations in plan without taking into account the natural topography and water flow from the buildings (Fig. 3.3).

Surface water is formed from atmospheric precipitation (storm and melt water). There are “foreign” surface waters, coming from elevated neighboring areas, and “our own”, formed directly at the construction site.

The site area must be protected from the influx of “alien” surface water, for which purpose it is intercepted and diverted off site. To intercept water, upland ditches or embankments are made along the boundaries of the construction site in its elevated part (Figure 1). To prevent rapid siltation, the longitudinal slope of drainage ditches must be at least 0.003.

“Own” surface water is diverted by imparting an appropriate slope when planning the site vertically and by constructing a network of open or closed drainage.

Each pit and trench, which are artificial catchment basins to which water actively flows during rains and snow melting, must be protected by drainage ditches and embanked on the upland side.

Figure 1. - Protection of the site from surface water inflow

In cases of heavy flooding of the site with groundwater with a high horizon level, the site is drained using open or closed drainage. Open drainage is usually arranged in the form of ditches up to 1.5 m deep, cut off with gentle slopes (1:2) and longitudinal slopes necessary for water flow. Closed drainage is usually trenches with slopes towards the discharge of water, filled with drainage material (crushed stone, gravel, coarse sand). When installing more efficient drainages, pipes perforated in the side surfaces - ceramic, concrete, asbestos-cement, wooden - are laid at the bottom of such a trench (Figure 2).

Figure 2 -Protection of closed drainage for drainage of the area

Such drains collect and drain water better, since the speed of water movement in the pipes is higher than in the drainage material. Closed drainages must be laid below the soil freezing level and have a longitudinal slope of at least 0.005

At the stage of preparing the site for construction, a geodetic alignment base must be created, which serves for planning and elevation justification when placing the project of buildings and structures to be erected on the site, as well as (subsequently) geodetic support at all stages of construction and after its completion.

A geodetic alignment basis for determining the position of construction objects in the plan is created mainly in the form of:

construction mesh, longitudinal and transverse axes that determine the location on the ground of the main buildings and structures and their dimensions, for the construction of enterprises and groups of buildings and structures;

red lines (or other development control lines), longitudinal and transverse axes that determine the location on the ground and the dimensions of the building, for the construction of individual buildings in cities and towns.

The construction grid is made in the form of square and rectangular figures, which are divided into main and additional (Figure 3). The length of the sides of the main grid figures is 200 - 400 m, and the additional ones - 20 ... 40 m.

The construction grid is usually designed on a construction site master plan, less often - on the topographic plan of the construction site. When designing a grid, the location of the grid points is determined on the construction plan (topographic plan), the method of preliminary layout of the grid and fixing the grid points on the ground is chosen.

Figure 3 - Construction grid

When designing a building grid there should be:

Maximum convenience for performing marking work is provided;

The main buildings and structures being erected are located inside the grid figures;

The grid lines are parallel to the main axes of the buildings being constructed and are located as close to them as possible;

Direct linear measurements are provided on all sides of the grid;

Grid points are located in places convenient for angular measurements with visibility to adjacent points, as well as in places that ensure their safety and stability.

High-altitude justification at the construction site is provided by high-altitude support points - construction benchmarks. Typically, reference points of the construction grid and red line are used as construction reference points. The elevation of each construction benchmark must be obtained from at least two benchmarks of the state or local geodetic network.

Creation of a geodetic alignment base is the responsibility of the customer. He must hand over to the contractor no less than 10 days before the start of construction and installation work technical documentation on the geodetic alignment base and on the points and signs of this base fixed on the construction site, including:

Construction grid points, red lines;

Axes that determine the position and dimensions of buildings and structures in plan, fixed by at least two leading signs for each separately located building or structure.

During the construction process, it is necessary to monitor the safety and stability of the signs of the geodetic alignment base, which is carried out by the construction organization.

Layout of earthworks

The breakdown of structures consists of establishing and securing their position on the ground. The breakdown is carried out using geodetic instruments and various measuring devices.

The layout of pits begins with the removal and securing on the ground (in accordance with the project) with alignment marks of the main working axes, which are usually taken as the main axes buildings I-I and II-II (Figure 4, a). After this, a cast-off is installed around the future pit at a distance of 2-3 m from its edge parallel to the main alignment axes (Figure 4, b).

Disposable cast-off (Figure 4, c) consists of metal posts driven into the ground or dug wooden poles and boards attached to them. The board must be at least 40 mm thick, have the edge facing upward, and be supported by at least three posts. More advanced is the inventory metal cast-off (Figure 4, d). To allow vehicles to pass through, there must be breaks in the cast-offs. If the terrain has a significant slope, the casting is done with ledges.

Figure 4 - Layout diagram of pits and trenches: a - pit layout diagram: b - cast-off diagram: c - single-use cast-off elements; d - inventory metal scraps: d - trench layout diagram; I-I and II-II - the main axes of the building; III-III - axes of the building walls; 1 - boundaries of the pit; 2 - cast-off; 3 - wire (mooring); 4 - plumb lines; 5 - board; 6 - nail; 7 - stand

The main alignment axes are transferred to the cast-off and, starting from them, all other axes of the building are marked. All axes are secured to the cast-off with nails or cuts and numbered. The axles are secured with paint on the metal cast-off. The dimensions of the pit at the top and bottom, as well as its other characteristic points, are marked with clearly visible pegs or milestones. After the construction of the underground part of the building, the main alignment axes are transferred to its base.

Surface water drainage (Vodootvod) is arranged for the purpose of draining surface water through trays, pipes and ditches to various low places and watercourses.

1. Types and methods of constructing surface water drainage.

2. General information on the drainage of surface water.

3. Specific example organizing water drainage from the surface of the site.

There are three types:

1. Open

2. Closed

3. Combined.

At open system surface water drainage and water houses are diverted through chutes or ditches into numerous low spots and watercourses. In the case of a closed water drainage system, surface water is collected in roadway trays or flows directly into water intake wells, and then through underground drainage pipes is discharged into thalwegs and watercourses.

At combined system drainage system, surface water is collected from the area adjacent to the house for discharge into an underground drain. In urban environments, open ditches are not suitable because they are difficult to maintain in a sanitary condition. In addition, it is necessary to arrange moving bridges for each house. It is best to drain water through trays, which in urban conditions are formed during the installation of valances - slopes. Subsequently, they are strengthened by paving or installing concrete curbs.

The minimum slope of trays or ditches is taken to be 0.05 ‰ and in exceptional cases it is taken to be 0.03 ‰. In cities and large settlements, closed drainage is widely used, especially with flat and flat terrain, which makes the operation of ditches and trays difficult. If there is an underground drainage system, then the terrain slope can be designed if necessary with a slope of less than 0.05 ‰.

In all low places of the sawtooth profile of the tray, water intake wells are placed every 50-60 meters.

Surface water drainage systems

When designing the drainage of surface water from a site, the direction of the main drainage mains is first determined. Then the direction of the main highways is combined with low-lying thalwegs. But mostly they install closed drains and place the highways in the direction of the slope of the area, along streets or buildings.

Drainage systems in areas adjacent to the drainage system are designed taking into account the discharge of surface water into the main highway. First, surface water, thanks to slopes, enters the drainage system (may consist of drainage pipes or trays) and is then diverted by slopes into drainage wells (in Figures 1 and 2). Drainage wells are located approximately 50-60 meters from each other and serve to receive water and further distribute it through pipes with a diameter of 30-40 centimeters into the street drain.

Every street (in urban and other developed populated areas) has its own drain and through an extensive network of pipe drains the entire flow is discharged into the main drain. The main drain receives the entire flow of wastewater and discharges it into the river or thalweg. When designing a main drain, the filling depth is calculated based on the possibility of further connecting to it all drain pipes from the adjacent streets of the settlement.

The slope of the drainage pipes is taken to be equal to the slope of the terrain or on the basis that when the pipe was filled to 1/3 of the height, the speed of wastewater in the drainage pipe was no less than 0.75 m/s. This speed in the drain pipe will prevent the accumulation of sediment in the pipe. In order to prevent water from freezing in the pipe when the soil freezes, the depth of laying the pipe is taken taking into account the depth of soil freezing. Wherein drainpipe drainage system is laid below the calculated depth of soil freezing.

Example of surface water drainage from a site

Site layout

Planning for the drainage of surface water from the area adjacent to the house requires large volumes of excavation work. For this reason, such matters cannot be done without special earth-moving and leveling equipment. The easiest way is to plan the surface of the site in such a way that the water flows by gravity to low places.

But this is not always possible. The reasons may be different, such as features of the local terrain or compact living. You cannot direct surface water from your territory to your neighbor.

Another option for draining surface water is to construct catchment wells. Such wells are located on design distance from each other and the slope of the site is planned in such a way that surface water flows directly onto them by gravity. From the water intake wells, water is directed further through pipes connected to the street pipe main for water drainage or have access to low places for discharge. To drain surface water using this method, it is necessary:

Laying pipes

Laying drainage pipes

1. Dig a trench around the entire perimeter of the house for laying pipes and give them the required slope. The minimum slope required for water drainage is 0.05 ‰. The diameter of the pipe is taken by calculation and depends on the catchment area and the estimated amount of sediment. In most cases, the pipe diameter is 15-30 cm.
Laying prefabricated water intake wells in the ground

Laying water intake wells

2. Water intake wells should be laid in the ground at the required distance from each other. Water intake wells can be prefabricated from reinforced concrete rings or monolithic from reinforced concrete.

Construction of monolithic reinforced concrete water intake wells

Construction of a monolithic reinforced concrete well

For the installation of monolithic reinforced concrete wells formwork should be put together and installed, then a knitted or welded frame should be made from steel construction fittings and install it in the formwork. Then you should fill concrete mixture and keep the concrete in the formwork for several days.

Underlying sand layer

Compaction of the sand layer

3. At the bottom of the dug trench, you need to place a supporting layer of sand approximately 30 cm high. The sand layer is made of coarse sand, and the surface of the sand cushion is also given the minimum required slope. Next, they begin to compact the sandy base layer and lay drainage pipes along the compacted sand layer.
Connecting drainage pipes to a well

Sealing joints cement mortar

4. The ends of the drainage pipes are placed inside the well and the joints are sealed with cement mortar. In this case, from the bottom of the pipe to the bottom of the well is left minimum height(15-40) cm required to clean wastewater from sludge. After connecting the drainage pipes to the wells, the drainage pipes should be filled with sand and compacted. Next, fill the trench layer by layer with soil and compact each filled layer of soil.
Installation of reinforced concrete cover

Reinforced concrete cover - hatch

5. The wells are closed with special prefabricated concrete covers, which can be made manually yourself or can be purchased assembled with concrete rings.

Well-maintained water intake well

Well-maintained water intake well

Installed above the reinforced concrete cover cast iron grate, which will prevent various debris and tree branches from entering the drainage well.

2.187. It is necessary to include permanent and temporary (for the construction period) devices for draining surface water in subgrade designs.

Surface drainage may not be provided for when designing subgrades in sandy areas in areas with arid climates.

The drainage of surface water to low areas of the relief and to culverts should be provided: from embankments and semi-embankments - ditches (upland, longitudinal and transverse drainage) or reserves; from the slopes of recesses and semi-recesses - by ditches (upland and behind-the-bank); from the main platform of the roadbed in excavations and semi-excavations - using ditches or trays.

2.188. A system of structures for collecting and draining surface water from the roadbed at the sites of industrial enterprises should be developed in conjunction with a vertical site layout project, taking into account sanitary conditions and requirements for the protection of water bodies from pollution wastewater and landscaping of the enterprise territory, as well as taking into account technical and economic indicators.

To collect and drain surface water, an open (ditches, trays, drainage ditches), closed (storm drainage system with a network of shallow and deep drainage systems) or a mixed drainage system is used.

2.189. The work on designing drainage devices includes: determining the volume of flow to the drainage devices of the catchment basin; selection of the type, size and location of the drainage device, allowing the use of earth-moving machines for its construction, as well as for cleaning during operation; the purpose of the longitudinal slope and speed of water flow, excluding the possibility of siltation or erosion of the riverbed with the adopted type of strengthening of slopes and bottom.

2.190. The minimum dimensions and other parameters of drainage devices should be assigned on the basis of hydraulic calculations, but not less than the values ​​given in table. 20.

Cuvettes should be designed, as a rule, with a trapezoidal transverse profile, and with appropriate justification - a semicircular one; In special cases, the depth of the ditches can be set to 0.4 m.

The greatest longitudinal slope of the bottom of drainage devices should be assigned taking into account the type of soil, the type of strengthening of slopes and the bottom of the ditch, as well as the permissible flow rates of water according to App. 9 and 10 of this Manual.

If the maximum permissible longitudinal slope of the drainage device for the given design parameters is less than the natural slope of the terrain or the longitudinal slope of the roadbed at water flow rates of more than 1 m 3 / s, it is necessary to provide for the installation of rapid flows and differences, designed individually.

Table 20

2.191. Cross section drainage devices should be checked for the passage of the calculated water flow using automated hydraulic calculations in accordance with App. 9 of this Manual. In this case, the probability of exceeding the estimated costs should be taken, %:

for pressure ditches and spillways................................................................. .5

longitudinal and transverse drainage ditches and trays........10

Upland and drainage ditches for railway tracks on the territories of industrial enterprises should be designed for flows with a probability of exceeding 10%.

2.192. On the watershed of two adjacent basins, it is necessary to provide for the construction of a dividing dam with an upper base of at least 2 m with slopes no steeper than 1:2, with its height exceeding at least 0.25 m above the design water level.

2.193. On on-site routes, an open drainage system is allowed only with appropriate instructions from the customer. When draining water by ditches in subsidence, swelling, and heaving soils, it is necessary in the design to provide measures against the infiltration of water from the ditches into the subgrade by appropriately strengthening them.

If it is necessary to pass water through a path, including for bypassing water from a ditch, inter-sleeper trays are used, and their depth is checked for sufficient depth to pass water at the existing marks of the bottom of the ditch.

2.194. It is not allowed to design the release of atmospheric water from ditches and ditches into:

watercourses flowing within a populated area and having a flow speed of less than 5 cm/s and a flow rate of less than 1 m/day;

stagnant ponds;

reservoirs in places specially designated for beaches;

fish ponds (without special permission);

closed ravines and lowlands prone to waterlogging;

eroded ravines without special strengthening of their channels and banks;

swampy floodplains.

2.195. When rain and melt waters are polluted by industrial waste from chemical enterprises, treatment facilities should be provided.

Drainage devices should be placed in the right of way. The distance from the outer edge of the slope of the drainage device to the boundary of the right of way must be at least 1 m.

In places where watercourses exit onto the slopes of ravines and lowlands, drainage devices must be laid away from the roadbed and their strengthening must be provided.

2.196. In areas with groundwater, upland ditches, as well as drainage devices within the excavations, should be developed in conjunction with measures for groundwater drainage. When the groundwater horizon lies at a depth of up to 2 m from the surface, the upland ditch can serve, with appropriate strengthening, to drain water from the subgrade, and when the groundwater lies deeper, deepening the upland ditch below the aquifer is prohibited. In this case, other measures are provided to protect the subgrade from the effects of groundwater.

2.197. With a closed system, water is drained from the enterprise site using storm drains. In this case, water is discharged from drainage trays, ditches and longitudinal drainage pipes into rainwater wells with gratings. In this case, the wells must have settling tanks, and the gratings must have clearances of no more than 50 mm.

2.198. A mixed drainage system in a built-up area is used in the following cases: when the requirements for landscaping the territory and the construction of storm sewers apply only to part of the site, and in the rest of it open drainage is acceptable when wastewater treatment is required.

With a mixed drainage system, the requirements for the installation of open and closed drainage systems must be observed.

2.199. The distance from the rainwater drainage pipelines to the axis of the extreme track of a railway with a 1520 mm gauge should be less than 4 m.

The distance between rainwater wells can be taken according to the table. 21.