An intelligent diagnostic system for identifying karst voids enclosed by layers with nano-cement mortar

Introduction. In the construction of residential and industrial buildings, analyzing the underground layers of soil on which the foundation is built plays a crucial role. Due to poor-quality geological exploration of the earth's surface, the problem of karst sinkholes is revealed during the construction of residential and industrial buildings. The paper proposes to carry out work on strengthening water-saturated and unstable soils in order to prevent collapse during the construction and operation of facilities for various purposes. Drilling wells in the karst formation zone and injection of reinforcing material is the main way to protect against karst phenomena. The paper examines gas-liquid layers (karst voids) containing nanocrystals located in a gaseous or liquid medium. The study of hydrodynamic fields is an urgent task that has a significant impact on the design and operation of facilities. Methods and materials. The most effective way to protect against karst phenomena for already built or newly erected buildings and industrial facilities is to drill wells in the karst formation zone and inject reinforcing material. As a result of the study conducted after the introduction of nanosilicon into a cement mortar, it is found that the hardening time of cement decreases with an increase in the number of nanoparticles of nanosilicon, i.e. nanoparticles have a higher rate of hydration reaction compared with cement. When a reinforcing material in the form of nanosilicon with cement mortar is introduced into the rock thickness of the karst formation zone, forming a lower insulating and upper stabilizing layer that prevent water access to the karst at the depth of the karst rock and stabilize the surface. At the karst formation stage, located within the boundaries of the collapse prism and corresponding to the width of the lower layer, two layers of the upper and lower supporting layer are created. Groundwater flow channels from catchments to discharge zones are formed between rock-thick support layers and insulating stabilizers that support the natural hydrogeological regime of the rock strata containing karst water layers. As a result, the protective properties of the rock increase when signs of karst appear, the physico-chemical and bearing properties of the soil improve, the strength properties of the soil increase and the likelihood of landslides decreases. Results. Hydrodynamic fields during filtration of nanogasated liquids in karst voids have been theoretically studied. Discussions. By installing a permanent automated monitoring system for motion sensors, pressure and temperature of liquid and gas in karst voids on the control well, we will be able to monitor the dynamics of the main hydrodynamic parameters of karst voids, allowing us to assess the current regime of karst voids and, in case of danger, alert emergency services and residents of the house. By monitoring the operation of sensors using artificial intelligence, it is possible to predict the occurrence and development of critical situations. Conclusion. The addition of silica nanoparticles to the cement mortar changes the rheological properties of the mortar, affecting its viscosity and fluidity. Groundwater flow channels from catchments to discharge zones are formed between rock-thick support layers and insulating stabilizers that support the natural hydrogeological regime of the rock strata containing karst water layers.