The Fifth International Symposium on Mine Safety Science and Engineering (ISMSSE2021)

85 / 2021-09-23 15:17:12

Study on fault activation characteristics and grouting simulation under fluid solid coupling

fluid solid coupling,Overburden failure,fault activation,grouting reinforcement,numerical simulation

In order to study thick loose bed thin bedrock deformation of working surface rock and the fault characteristics and grouting reinforcement effect "activation", based on the geological conditions of coal mine 331 working face of jining in shandong province as the background, first has carried on the stope roof in mining under the influence of fracture structure plane stress deformation analysis, using FLAC3D numerical simulation software, Simulated in mining influence, fluid-structure interaction and grouting strengthening three kinds of fault condition, the working face extraction step by step in the direction from the footwall fault dynamic process, analyzes the fault displacement difference of both sides of internal stress and fault of space-time evolution, strata and the variation characteristics of the plastic zone along the fault and the formation law of pore water pressure and seepage flow vector. The results show that: 1. Under the action of fluid-structure coupling, when the working face advances near the fault, the soil layer at the bottom of the fault and the loose layer will be damaged in advance and communicate with the water-conducting fracture zone to form a seepage water-conducting channel. 2. When the working face pushes through the fault, the height of the caving zone increases suddenly at the fault fracture zone, but remains unchanged on both sides of the fault. This phenomenon is more obvious under the fluid-structure interaction. 3. Activation occurs first at high faults. Under fluid-structure coupling, when the working face is 30m before and after mining the fault, the risk of fault activation is the highest and water inrush accidents are easy to occur. 4. After grouting reinforcement in the fault zone, the failure of the working face does not occur until 30m away from the fault, the pore water pressure of overburden decreases, the plastic zone area of the fault zone decreases, and the displacement and stress peak values of the two sides of the fault also decrease, which can effectively reduce the risk of fault "activation". This provides a scientific basis for safe mining across fault in Yangcun coal mine.