[Reconstruction features of drainage systems in cohesive soils]
2008
Klimkov, V.T. | Kazmiruk, I.Ch. | Mitrakhovich, A.I., National Academy of Sciences. Scientific and Practical Center for Arable Farming (Belarus). Institute for Land Reclamation
Characteristics of processes and effects connected with physical and mechanical properties of clay soils are stated. Function of protective - filter materials in drainage work is shown. It is shown that straw is the most preferable material due to their filtration characteristic. Similar, but more long - lived material is necessary, nonwoven polymeric cloth with fibres in diameter at 10 - 20 more than already known, for example, needle piercing materials. Analytic dependences for calculation of drainage parameters in cohesive soils with respect to imperfection of absorbing wells and contact strength structures are presented. It was stated that water intake capacity of absorbing drains in cohesive soils can be increased with the use of volume filters. Drainage from ceramic pipes does not satisfy to these conditions and it should not be used at reconstruction of drying systems. In drainage made of ceramic pipes the area of backlashes in butts through which water arrives in pipes, does not exceed 4 square cm/m, that in many respects explains low drying act of drainage. It is necessary to notice, that in laboratory experiences it is practically impossible to predict all processes and the phenomena occurring in drainage in natural conditions during long term of its action (25 years and more). For this period essential changes can occur in near drain zone when as a results contact resistance will inevitably increase because of clogging and overgrowing of entrance apertures of a pipe by various water organisms. Therefore at drainage reconstruction it is recommended to use plastic drainage pipes from polyvinylchloride or polyethylene with the area of water intake holes being no less than 20 square cm/m with double stock
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