Dynamics of the infiltration of liquid pollution into the ballast section of a railway track within the framework of Forchheimer’s law

Summary

The dynamics of a liquid layer infiltration into porous soil induced by the gravitational forces is considered within the framework of the two-term filtration law (Forchheimer’s filtration law). Simple formulas are obtained for the time dependence of the height of the liquid layer on the soil and the time of complete infiltration of liquid into the soil on the filtration coefficient and porosity of the soil. It is shown that the total infiltration time is directly proportional to the height of the initial liquid layer on the ground. Calculations of the time and average speed of complete infiltration for typical soils were carried out.

Key words

infiltration , ballast section , liquid pollution , body of ballast , porous soil , infiltration time , porosity , filtration of coefficient

Filtering materials for the domestic water supply

Summary

The results of laboratory and pilot tests of the following filtering materials used for water purification in a domestic water supply system: Diamiks Akva, granodiorite sand, ODM-2F and ODM-5F are presented. The manufacturers of the filtering materials are indicated. The basic chemical composition of the filtering materials is given. The raw material for Diamiks Akva is based on natural diatomite that contains exoskeletons of diatoms. The poured bulk density of Diamiks Akva is 820 kg/m³. Granodiorite sand is a product of crushing granodiorite rock with a poured bulk density of 1498 km/m³. For ODM-2F opokas from the Artemovsk deposit in the Sverdlovsk region with a poured bulk density 680 kg/m³ are used. ODM-5F is a sorption material prepared on the basis of siliceous diatomaceous earth (kieselguhr, tripolith and diatomite) with a poured bulk density of 700 mg/m³. The studied filtering materials have the certificates of registration. The results of studying the physical and mechanical properties of filtering materials are presented; the granulometric composition is given, the intensity of washing depending on the degree of expansion is established. The research results showed that filtering materials made of Diamiks Akva and granodiorite sand can be used as media in newly constructed filtering facilities. Higher washing intensity is required for the regeneration of the specified filter media. ODM-2F and ODM-5F filtering materials do not involve higher costs during the regeneration of the media since the drainage and distribution systems of rapid filters provide for the capacity of the washing flow.

Key words

filtering material , bulk density , physical integrity , backwash rate , porosity , domestic water