Method and device for monitoring generation of coal mine vibration and its response to vibration wave

A method for monitoring generation of coal mine vibration and its response to vibration wave, comprising:

• S1, determining a number and spatial location of high-level thick-hard rock layers in an entire formation of a mining area,
• S1-1 investigating a thickness, lithology, and stratigraphic sequence of rock layers in the entire formation,
• S1-2 measuring and calculating engineering geological parameters of the rock layers in the entire formation of the mining area, including a vertical distance Hn between the rock layers with a single layer thickness of over 60 m and the coal seam, a ultimate tensile strength σtn of the rock layers, a hardness coefficient fn of the rock layers, an elastic modulus En of the rock layers, a Poisson's ratio vn, and a maximum deflection wn of the rock layers;
• an average bulk density of the rock layers γ, and an original rock stress at the rock layers with a single layer thickness over 60 m σ1n, σ2n, σ3n;
• a comprehensive fracture angle α of the rock layers in a stope face, a burial depth of the coal seam, and a stope face slant length Sl,
• S1-3 determining a number and an arrangement of the high-level thick-hard rock layers based on the engineering geological parameters of the rock layers calculated by S1-2, wherein, the rock layers located more than 150 m away from the coal seam and with a comprehensive score fn greater than 80 are identified as the high-level thick-hard rock layers capable of generating high-energy and strong vibrations;
• S2, based on the engineering geological parameters obtained in step S1, calculating a fracture length Ldn when each of the high-level thick-hard rock layers break and a corresponding stope face mining distance Lcn when each of the high-level thick-hard rock layers breaks, and determining a similarity ratio k of an experimental model based on a coal seam burial depth in the area where the coal seam is located and actual spatial conditions in a laboratory, and based on the similarity ratio k, calculating a distance x0n from a vibration source position of the experimental model to an excavation starting position, as well as a corresponding excavation distance Lwn;
• S3, calculating a true energy EDn for the fracture of the high-level thick-hard rock layers;
• and
• using a vibration triggering device to generate vibration source energy, the vibration source energy used in the vibration triggering device is a CO2 detonation device, and calculating an equivalent relationship between the true energy EDn generated by the fracture of the high-level thick-hard rock layers in the area where the coal seam is located and an equivalent energy Egn released by the CO2 detonation device of the vibration triggering device;
• S4, laying high-level thick-hard simulation rock blocks within a height adjustable frame, from bottom to top of the formation, and during laying of the high-level thick-hard simulation rock blocks, according to the distance x0n from the vibration source position of the experimental model calculated in step S2 to the excavation starting position, burying the vibration triggering device at the corresponding position in the formation;
• after laying the experimental model, the frame is at least 20 cm higher than the formation;
• installing an underground monitoring system at the bottom or front of the experimental model to monitor strong vibration impact on underground buildings;
• installing an surface building model at the top of the experimental model, and installing an surface monitoring system at a height of 10 cm above the surface building model;
• S5, simulating triggering of the strong vibrations:
• a. simulating coal seam mining in the stope face, and slowing down an excavation speed when the excavation reaches the distance Lwn or nLwn where the high-level thick-hard rock layer is fractured, the vibration triggering device operates and triggers a high-energy and strong vibration phenomenon;
• b. continuing excavation until the coal seam excavation is completed, after vibration triggering simulation, continuing excavation to trigger the next high-energy and strong vibration by the fracture of the high-level thick-hard rock layer, thus conducting multiple high-energy and strong vibration simulations;
• c. the underground monitoring system and surface monitoring system obtain micro deformation and fracture information of a surrounding rock underground, a residual energy intensity information of the mining location, and a vibration velocity information in three mutually perpendicular directions on the surface, which are used to analyze the strong vibration impact in the actual mining area.