Construction of Time-Space Structure Model of Deep Stope and Stability Analysis

To quantitatively characterize the evolution process of disaster-causing stress fields and to analyze the whole time domain characteristics of a stope from moving to stability, we constructed the four-dimensional time-space structure model of deep stope using PFC discrete element modeling software, and embedded transducers in the goaf area to monitor overlying strata movement characteristics. Targeting the gangue in the goaf area, the compression characteristics, energy absorption characteristics, and evolution of hulking coefficient over time during compaction are analyzed under different mining conditions. Results indicate that: 1. In the first stage of development of overlying strata, an intact time-space structure model of the stope cannot be formed. This means the stope structure has not reached final mechanical equilibrium. 2. Compression of the gangue fragments is an important mechanism of energy release of key strata as the strata are ruptured. The energy absorbed by the gangue reaches the maximum when the intact time-space structure model of the stope is formed. 3. The strength of the immediate roof is directly related to the development of the stope structure. 4. The development of the time-space structure of the stope is divided into two stages, which are marked by the time point when the advance distance is equal to the width of the working face. The above analysis can explain reasons for the delayed occurrence of dynamic disasters, laying a basis for reducing dynamic disasters.