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Requirements for setting up drainage channels at construction sites

23-3-2020 page view: 0

The main function of drainage channel in construction site is to discharge rain water, living water and production water during the construction to the off-site in an organized way, so as to ensure that there is no stagnant water within the scope of the construction site. In order to achieve this goal, the drainage channel should be set up to meet the drainage requirements in the construction site.

Ditch installation

General principles for setting up drainage channels:

(1)In general, the drainage channel should be set where they do not affect proposed or existing buildings and where materials are stacked, processed and transported, and people walk.

a. The drainage channel shall meet the objective requirements of collecting and discharging water on site. It contains five meanings: firstly, the number of drainage channels must meet the discharge of water at every corner of the site. Secondly, to determine the section of the drainage channel, because only adequate cross-sectional area could collect the site water and quickly discharge it away from the construction site. Thirdly, the drainage channel should be in the low slope of the site. Then, the drainage channel itself should also have a certain slope. Finally, in order to prevent the drainage channel from being damaged by heavy load vehicles or cold weather in winter, the buried drainage channel should have certain depth.

b. The drainage ditch shall adopt one or several separate or combined drainage methods according to the specific conditions of the construction site. That is to say, it shall be flexibly used according to the actual conditions of the construction site.

(2)For the convenience of the construction site, we introduce several types of drainage channel sections which made in the construction site.

Natural drainage channel

Natural drainage channel is excavated by using the natural conditions of the construction site which is time-saving and labor-saving. Laying pebbles or gravels at the bottom of the channel can not only avoid the erosion of water flow, which is conducive to protecting the bottom of the ditch, but also can precipitate the dirt in the water. Natural drain is often used in construction projects that are small in scale, short in duration or where water or rain is not very large during the construction.

Open ditch

Open ditch is usually made with hardened ground in site, its advantages are labor saving, material saving and economy. The function of drainage channel is also very clear, the drawback is the section should not be large, especially the construction site is relatively small, the depth and size are limited and the drainage capacity is difficult, at the same time, it is also easy to affect or hinder the walking of the construction personnel and construction machinery during construction. But it is feasible for the construction period is short, the building scale is small, less rainfall season construction and winter construction of the project.

Surface drain

Surface drain is actually U shape with cross section, the bottom plate is cast-in-situ concrete, if the width of the surface drain is greater than 500mm, it shall be equipped with appropriate amount of transverse reinforcement in the bottom plate to prevent concrete from breaking, Most vertical walls of drainage channel adopt the method of wiping waterproof mortar inside brick masonry, it is best to top with a cast-iron rainwater grate, rainwater from the surface of the site enters to the channel through the grates can be timely discharged. The biggest advantage of surface drain is that it does not affect any production activities in construction, and the construction site is also tidy which is easy to meet the requirements of civilized construction site.

In order to save money, many construction enterprises now use the steel scraps in the project to weld drainage grates instead of finished cast iron grates, and the effect is also good. However, attention should be paid to the use of screw rebar with a diameter of more than 20mm, and the spacing of rebar should not be greater than 40mm. Too fine rebar can not bear the heavy load, too large rebar spacing easy to sprain feet or wheelbarrow tires into. For further savings, the grates of rebar rainwater can also be welded to a fixed size for long-term and repeated use.

When visible drainage system is not allowed at the construction site, it is usually use blind drain, which is similar to our common highway drainage. Resin concrete material, resistant to chemical and biological erosion, quick and convenient installation and has a long service life. It can be equipped with grating covers of different materials, such as cast iron, stainless steel grating, slot cover, resin and stainless steel stamping grate covers. It can be selected according to different installation sites and loading classes.

In addition, it is suggested to set up a sump pit at intervals of about 15-30m in the sports field and at the corner of the drainage channel, so that the cleaning and maintenance work can be more convenient, with the purpose of facilitating inspection and dredging of pipes at ordinary times.

Sump pit

Sump pit

Blind drain is a very popular and commonly used drainage method, the most popularity is polymer concrete drainage channel, good quality, convenient and fast construction, male and female groove connection is simple and installation is efficient.

The advantage of the blind drain - polymer concrete drainage channel is never hinder any production activities on the ground, and the U-shaped and smooth inner wall makes high drainage efficiency, not easy to block, the most important is the beautiful effect of the ground after installation, so it is widely used in various venues, such as commercial streets, squares, gardens and sports fields.

Stainless steel grating drainage channel

Blind drain

(3) The longitudinal slope of the drain shall be determined according to the topography and the maximum displacement, generally not less than 0.3%, not less than 0.2% in flat areas and 0.1% in swampy areas. If the blind drain is used, there is no slope in drainage channel itself. Now we can find slope by ourselves or implement slope requirements in the form of sump pit.

(4) Our country has a vast territory, the climate varies greatly from different regions. It is difficult to unify the drainage section of the construction site with one standard, so it can only be expressed in the language of principle, that is, the section of the drainage channel should be in accordance with the maximum flow within the construction period, more directly, as long as the section of the drainage channel can discharge project waste water, rainwater and living water smoothly out of the construction site, and not appear hydrops at the construction site due to the limitation of drainage capacity.

(5)When using natural drainage channel, the side slope grade shall be determined according to the quality of the soil and the depth of the drainage channel. In general, it can be determined as 1:0.7-1:1.5, only the rock slope can be properly steepened. In order to ensure that the soil at the bottom of the natural drainage channel is not washed away by the flow, a layer of gravel or pebble with a minimum thickness of 40-60mm can be laid at the bottom of the channel.

(6)When using any type of drainage channel, its outlets shall be set in low-lying locations away from buildings and structures, and it shall also take measures to prevent freezing at the outlet of spray drains and dark pipes.

(7)The drainage channel may have landslide and collapse when the local shape and geological conditions are complex. At the moment, the design, construction, supervision and geological investigation units shall be invited to jointly determine the drainage plan, and then organize the implementation of the drainage channel according to the determined scheme.


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