Investigation on groove depth of artificial dam of underground reservoir in coal mines

Water storage in underground reservoirs serves as an important means of water resource protection in coal mines in Western China. The groove depths of the artificial dam required plays an important role in the design of these underground reservoirs. The underground reservoir of the Wulanmulun coal mine was examined in this study using theoretical analysis and similar simulation experiment, and the groove depth was optimized using FLAC(3D) based on the results obtained. According to the theoretical calculation model of the groove depth, the safe groove depth was determined to be 0.2 m. It was found that the groove was the weakest point in the reservoir with the most serious seepage and maximum likelihood of failure. The variation curve of the volume of the plastic zone followed a U-shaped distribution. The side, roof, and floor depths corresponding to the minimum volume of the plastic zone were determined to be 0.6 m, 0.2 m, and 0.3 m, respectively. The analysis indicates that increasing the groove depth within a certain range can enhance the stability of the reservoir; however, as the groove depth exceeds a critical value, the increase in groove depth was unfavorable for the stability of the reservoir. Moreover, increasing the side groove depth above the critical value was more effective in enhancing the stability of the reservoir than increasing the roof and floor groove depths.