Choice and features of drainage system
For a right choice of drainage system it is necessary to calculate a quantity of water which it is required to take away from a site. For this purpose it is necessary to learn:
– volume of inflow of water for the settlement period of time;
– level of a zaleganiye of ground waters;
– soil type;
– earth vlagonasyshchennost;
– factor of a filtration of soil for every period of year.
Not including that, at a choice of drainage system it is necessary to consider a land relief, on it depends, whether water samoteky can be taken away or it is necessary to use pumps.
It is worth to remember about technological properties of the most drainage system: diameter of drains, their permeability, difficulty of installation of system and carrying out preliminary works. Has huge value and a material of drains. Earlier glinyany pipes were used, when laying between them gaps in 1,5-2 mm should be left, through these openings water got to drains and, In practice it was not possible to lay pipes with suitable accuracy therefore efficiency of a drainage with application of clay drains was not high.
Other out-of-date material which still from time to time use at installation of drainage systems is a fibrocement. In drains from this material before laying bore through openings which promptly get littered at operation. Now drains from cellophane and PVC deprived of the above-named defects are extensively used.
It is necessary to take into consideration and mission of constructions. For example, for a cottage being in the distance from underground communications, the deepest will approach horizontal small stones with cleaning in filtering trenches, and the multilevel parking in the small town will need some levels of a horizontal drainage together with a drainage beam and with the following assignment of water in a storm ditch.
Features of installation of drainage systems.
Quality of a drainage almost in everything is in dependence from observance of certain rules at its installation.
1. Soil round drains should be water-permeable. Therefore at installation of drainage system round pipes posloyno stack filtrational materials. For example, on day of a trench will mix a sand or shchebenka layer, on it stack drains and fill up with a layer of sand and gravel on which creep geotextiles, sand then is filled, and the natural soil layer from above keeps within.
2. Drains keep within under a bias towards a drainage well. The good bias considered 5-10 mm on 1 meter.
3. The bias of drainage pipes should be uniform on all their extent, in particular it is burning at soil inclined to a silting.
4. The Vodopriimny well establish in the lowest point of a relief.