Features of Rock Research During Forensic Soil Examination

Abstract

The features of forensic research of rock fragments are determined, taking into account the specifics of expert examination of objects as multicomponent systems. Soil heterogeneity is caused by two reasons. The first is the nature of soil components. Most objects of soil and mineral origin are polymineral and consist of different components, each of which is characterised by different nature and properties. The main criteria (requirements) that must be taken into account during comparative forensic examination of rocks and other multicomponent systems are presented. The most common multicomponent systems found in soils include rocks, anthropogenic slags, and hydraulic binder-based building materials.

The second reason is that most soil indicators depend on mechanical (granulometric) composition. When conducting forensic soil examinations in comparative studies of rock fragments and other multicomponent systems (slags, building materials) in order to obtain objective and reliable results, the following two requirements must be met: firstly, to examine fractions of the same size, and secondly, to examine all components of the objects presented separately. The smallest fractions of objects of soil and mineral origin (clay fractions of soils, finely dispersed fractions of binding components of building mortars) are the most homogeneous in chemical composition and therefore must be studied quantitatively. Large fractions (sandy fractions in soils, sandy-crushed fillers of building mortars), on the contrary, are very heterogeneous and must be examined for their qualitative composition.

The study of the most common rocks does not go beyond the special knowledge of an expert in the expert specialty 8.8 ‘Soil Research’, but the establishment of the brand or other technological indicators of the prepared commercial product, as well as the determination of its scope of application, cannot be resolved within the framework of a forensic soil examination.