Abstract:
In order to further improve the means of model experimental research in the field of underground coal mine engineering and to clarify the law of underground water transport in coal mining in mining areas, a set of comprehensive intelligent test platform for underground water transport in multi-seam mining has been developed. It consists of five key units, including the main reaction force unit, servo-loading unit, recovery simulation unit, water transport unit and information acquisition unit. The combined reaction device enables geomechanical model tests to be carried out on model bodies of different sizes up to 2.1 m × 1.8 m × 3.0 m (
L ×
H ×
W). Seven servo-electric cylinders are used to achieve active and stable loading in different areas, which can restore the real stress field distribution characteristics of the surrounding rock of underground projects and expand the effective loading area. The innovative design of the coal seam retrieval simulation device is applicable to the retrieval simulation of coal seams with different thicknesses, different feed lengths and different retrieval rates. Fluorescent tracers and high power UV light sources are used to show the seepage, transport and storage of water along the fractures. A servo-hydraulic control system, high precision earth pressure box and distributed optical fiber are used to achieve real-time data collection and improve the accuracy of data collection. Using the mining geological conditions of Shangwan Coal Mine in the Shendong Mining Area as the basic background, field tests are conducted. The results show that the deformation pattern of the surrounding rock of the model roadway during coal seam mining matches with the actual measurement in the field, and the main characteristics of the surrounding rock deformation are the same. The greater the distance of the lower coal pillar, the greater the horizontal bearing capacity, but the damage process is more violent, resulting in a greater range of damage to the top and bottom slabs, the horizontal bearing capacity limit of the lower coal pillar is 0.32 MPa, and the critical displacement of the fissure penetration is 2.5 mm. The vertical fissures are the main channel through the underground water reservoir of the coalmine and the overlying aquifer, and are the main path for water recharge; the lateral fissures of the top rock layer become the water storage space, and the mining area is the main water storage space. The feasibility and reliability of the system have been verified through tests, which better reflect the fracture development, stress changes and groundwater transport characteristics of the model rock layer under mining conditions, and have certain engineering application value, providing a scientific research tool for the construction and long-term safe operation of underground reservoirs.