# Control and Analysis of Layered Soil Structure to Ensure Railway Roadbed Stability
## 2 A Description of the Laboratory Experiment  
The most promising approaches for the automated monitoring of railway roadbeds are geoelectric probing methods [13]. These methods are particularly promising for as sessing the layered structure of soil beneath railway tracks, where even minor variations can significantly impact track stability [14]. The ability to accurately observe and assess geological formations, coupled with advanced predictive analysis capabilities, is essential for maintaining the integrity of railway infrastructure. The use of vector measurement systems that register phase characteristics of the electromagnetic field enhances the precision of soil monitoring by reducing data ambiguity and improving the reliability of the information used to manage and reinforce railway tracks [15; 16]. Phase-metric systems are used under both laboratory and field conditions. They are fundamental for geoelectric control, which plays a critical role in detecting and localizing geodynamic processes that could affect railway stability [17; 18]. Different layers of rocks may differ in moisture saturation and granulometric composition, which in turn affects the change in their electrical characteristics. In this context, the objects of control are the process equipment, the well, and the surrounding soil. A method for modeling the physical and geological environment involves using equivalent circuits represented as dielectrics [18; 19]. This method states that an equivalent circuit containing parallel or series-connected active and capacitive resistances can be an electrical model for analyzing the studied environment. Geophysical measurement data, such as electric current, electric field, seismic waves, and other physical parameters, are used during modeling. These measurements are used to calculate active and capacitive resistances in the equivalent circuit of the model. This approach allows for a detailed study of the physical properties of the soil, such as its electrical conductivity and permittivity. In addition, this method enables the determination of geological parameters such as the depth and distribution of different soil layers, which enriches our understanding of the physical processes in the geological environment. In our case, the geological environment is abstracted as connected particle equivalent circuits, where each particle represents a microregion of the studied environment. To analyze the electrical properties, the cell encompassing the environment and the object of study are described by two resistances: \(R_{1}\) and \(R_{2}\). \(R_{1}\) is a resistance that characterizes the dielectric properties of the environment and is purely reactive. This resistance is associated with permittivity and affects the ability of the environment to respond to an alternating electric field. Resistance \(R_{2}\) is a parallel connection of the active resistances of two different environments. This reflects the consideration of the specific resistance of the objects being isolated, which may differ from the surrounding environment. This approach allows for a more accurate consideration of the influence of geological formations, such as mineral inclusions or water layers, on the electrical conductivity of the overall environment. Thus, the proposed model integrates the concepts of reactive and active resistance, as well as the specific resistance of objects, for a detailed study of the electrical conductivity of the geological environment. Analysis of these parameters using the particle substitution scheme allows for more in-depth studies related to the influence of geological formations on the electrical properties of the environment. When modeling a medium, a complex electrical circuit arises because of connecting cells, which can be calculated using the nodal potential method (NPM). The main advantage of the NPM is its ability to effectively describe complex electrical circuits, including modeling a medium with many cells.