Measuring the Influence of Soils on the Movement of Terrain Vehicles in the Czech Republic

One of the most important physical properties of soils is their compactness related to grain size. This property is one of the main parameters in assessing the passability of soils by off-road vehicles (especially tractors, rescue, and military vehicles). The aim in the presented study was to test the bearing capacity of soils in the Czech Republic in order to assess the mobility of off-road vehicles. Soil penetrometry and analysis of soil samples, taken in the field from places where were performed, soil penetrometric measurements were used as the main method for assessing soil compaction. The measurement sites were selected to represent the main soil types in the Czech Republic in terms of their occurrence and the size of their area. Although soil types were determined from previous measurements and tests, samples were newly taken from each site for laboratory analyses of soil granularity. Measurements and sampling were performed from 3 representative surface layers (0–15 cm, 15–30 cm and 30–45 cm). Each of these layers corresponds to the respective influence of the vehicle type (light, medium, and heavy vehicles) on the subsoil. The main results of field measurements include the determination of the Cone Index (CI), Remolding Index (RI) values, which are the most important for assessing the passability of the terrain. These values were compared with the vehicle cone index (VCI) values, representing the technical characteristics of the vehicles, in particular their pressure per area unit. Determining the soil granularity of individual tested soil species was an important result, necessary for the inclusion of soils in the international soil classification system—Unified Soil Classification System (USCS). The achieved results document the most extensive campaign of penetrometric measurements, covering the entire territory of the Czech Republic. The methods used and the results obtained can be used not only for determining the terrain passability for military vehicles, but also for any off-road vehicles used in agriculture, in the integrated rescue system, but also for any vehicles moving in open terrain.