Impact of oil products on spectrographic composition and physical-mechanical propertiesof sand-clay soils (by example of Tomsk)

The purpose of the research is to study the impact of oil products on physical-mechanical propertiesof soils. This article is topical because in our time filling stations are actively built in urban areas; as a consequence, the urban areais more subjected to pollution. Earlier these objects took place outside the urban area. Now oil stations are situated near industrial andcivic objects. In Tomsk there are more than 40 oil stations. The medium period of depletion of the main equipment validity without itsreplacement before large leaks (for example, an underground petrol tank) is about 18 years. Some oil stations situated directly on theterritory of Tomsk are 25-30 years old. Mineral oil pollution results in the change of the composition and behaviour of soils. The factthat the zone of pollution extends over the border of oil station areas makes it necessary to studying the changes in the composition andbehaviour of the polluted soils. The research was based on the data of Tomsk geological organizations and personal experiments. Altogethermore than 100 complex analyses of physical-mechanical soil properties were examined. The analysis demonstrated that under theinfluence of oil products the grading of soil changes - the content of clay fraction is increasing, which is conditioned by the presence oforganic impurity (in these case mineral oils) in soil that leads to forming the reducing environment. Destruction of cementation connectionsin clay soils with Eh < 0 occurs through transformation of Fe3+ compounds to Fe2+ form. Fe2+ in the soils can lead to destructionof equipment and increase of fine-dispersed content that can be accompanied by the rise of clay sediments hydrophilicity. Changes ofcontent are more characteristic of loamy soil than loamy sand. This is due to the fact that loamy soil contains more fine-dispersed fraction,which can be destroyed at the contact of mineral oil with the soil than loamy sand. The compression of oil products that pollute soildepends on the initial humidity of soil. The less the humidity of soils is, the more the soil is compressed after the oil products influence.Lasting pollution can lead to an increase of the soil compressibility due to an increase in the index of plasticity as soil compressibility offine-dispersed soil increases at the decrease of the particles size. Changes of mechanical properties of polluted soils occur in the followingway: the value of the cohesive strength of the polluted soil increases (due to the increase of fine-dispersed fraction) but the elevationangle decreases (due to the oiling of the free pore space by oil products). As a whole it is possible to tell that changes are mainly negativefor stability of soils in the sphere of their influence upon the constructions.

Keywords

Authors

References