Abstract:
With the continuous development of China's coal resources to the deep end, the complex conditions of rock stratum existence bring great challenges to the construction and use of shafts. Deep vertical shafts often traverse multi-layer aquifers, and the seepage problem of the shaft wall caused by roof pressure water is particularly serious, which not only threatens the mine safety, but also brings challenges to the traditional grouting management methods, such as high cost, difficult construction and repeated seepage problems. In this regard, a set of visual similar simulation experiment platform was established based on the hydrophobic pressure reduction theory, simulated the water pressure of the well wall and the change of the flow rate of the water discharge holes under the conditions of different rock formations and different number of water discharge holes, analyzed the flow rate and seepage law of the water discharge holes, the development law of the morphology of the groundwater landing funnels, and the change law of the seepage water pressure and the pressure law of the well wall. And take Binchang Wenjiapo coal mine as an example to carry out on-site water discharge test. The results show that: the flow rate at the outlet increases with the increase of pipe diameter; the water flow rate of two holes increases more than that of a single hole, and the water flow rate of three holes increases less; the closer to the well, the deeper the water level drops, the influence range of the landing funnel increases with the increase of the number of discharge holes, the shape of the landing funnel of the single-layer water discharge experiment is kept symmetrically with the descending holes, and the bottom end of the funnel shows a conical shape. The water pressure decreases quickly in the early stage of water discharge, and tends to stabilize in the later stage; the results of the simulation experiment are applied to the field, and the single-hole and double-hole water discharge tests are carried out by drilling sparse discharge holes between the main and auxiliary wells of the Wenjiapo Mine, and the stabilized water influx in the single-hole is 75 m
3/h, and the stabilized water influx in the double-hole is 175 m
3/h. The test has significantly lowered the groundwater level, and formed the landing funnel with a maximum depth of 40 m. The actual measurement in the field is more in agreement with the results of the simulation experiment, which verifies the similarity with the results of the simulation experiment. Simulation test results are more consistent, verifying the scientific and practical effect of the hydrophobic bucking management method. The results of this research can help to promote the progress of wellbore water seepage control technology under the influence of deep roof pressurized aquifer.