Predicting Unit Pressure Indispendable for Generation of Specific Compaction of a Soil Sample

The objective of the research was to construct an empirical model for prediction of a unit pressure indispensable for generation of a specific compaction of soil samples. Soil material in the form of loose mass was collected from the soil layer deposited in the depth from 35 to 40 cm and then its typical properties were determined (textural group, density of solid particles, humus content, reaction, plastic and liquid limits) and in order to compact it in Proctor apparatus and in the uniaxial compression test. Results of both tests were used for construction of regression models reflecting the course of the unit strength (P_ρd) necessary to generate compaction (ρ_dj) equal to the dry bulk density obtained in Proctor apparatus (ρ_dp), in relation to the sample moisture (ρ_dm). Searching for relations was restricted to the scope of moisure between an optimal one acc. to Proctor and the soil plastic limit. It was stated that the pressure value Pρ_dp made on the soil sample in the uniaxial compression test depends significantly on w_s and ρ_dm, and for description of this relation the use of multiple regression is sufficient. It was found out that for model samples with a textural group of silt loam and loam, differences in dry bulk density obtained in Proctor apparatus are approximately up to 0.15 g⋅cm⁻³.