Interpretation of Gravity Monitoring Data on Geotechnical Impact on the Geological Environment

摘要

The Verkhnekamskoye potassium salt deposit located in the Perm Krai is the main source of raw materials for the potash industry in Russia. The penetration of underground waters into the shafts of the mine, which is situated beneath the industrial zone, and residential quarters of the city of Berezniki led to the flooding of the mine with subsequent collapsing of the earth's surface. For obtaining the information about negative impacts of engineering processes associated with mineral mining operations, a method of highly accurate gravimetric monitoring observations is suggested, suitable for tracking the time changes of the gravitational field. As a result of monitoring observations we obtain a dynamic anomaly of gravity which is defined as the difference between the subsequent and the previous gravity values. Since all the unvarying components of the gravitational field are present in each pair of the observations, the dynamic anomaly only reflects a specific geological or mining process. The method for processing and interpretation of the dynamic anomalies of gravity, which synthesizes qualitative and quantitative approaches to extracting the geological information from gravity data, is developed. The interpretation yields the areal distribution and probable depth interval of the zone of rock decompaction and shows the magnitude of the change in the density of rocks characterizing the intensity of the decompaction process. The practical implementation of the highly accurate gravimetric monitoring observations is carried out in the emergency sites of the mines of the Verkhnekamskoye potassium salt deposit has demonstrated high efficiency of the suggested method.