Basic Soil Properties of a Number of Artificial Clay - Sand Mixtures Determined as a Function of Sand Content

Soil mixtures were composed from the Polish Neogene clays occurring on the Polish Lowland and the fine-grained dune sand in weight proportions of the dried components. As the products of mixing, new soils were obtained, having modified physical, mechanical and screening properties as a function of their different granular and mineral composition. The granular composition varies from the soils which are similar to clays, through the clay loam, sandy clay loam up to sandy loam. With comparison to the untreated clay, soil mixtures by far compact better and achieve lower values of porosity index n and void ratio e (n 27-22%; e 0.37-0.29; raw clay n 43%, e 0.76), and therefore they achieve lower values of coefficient of permeability (k 1.83 · 10-9 to 2 · 10-11 m/s) by maximum compaction. The soil mixtures show lower values of free swelling and linear shrinkage (FSHG 40-20%; LS 10.6-7.4%; raw clay: FSHG 70%; LS 14.7%. The mentioned features are crucial while selecting the mineral component of the lining system of burdensome objects such as landfills. Moreover, shear parameters of clay mixtures are improved as compared to the raw clay: starting from the angle of internal friction &varphi 6.2(°) ; and cohesion c 46.6 kPa by raw clay, to &varphi 33.5(°) ; and c 43.5 kPa by the soil mixture showing the highest sand content among the modeled soils. The values of the mentioned parameters are fundamental by selecting of mineral lining, and in course of construction of earth objects.