Study on connectivity of karst water conduction channel in the process of pit water sealing

Affected by the heterogeneity of karst development in aquifers, the exploration of the spatial distribution of water-sinking water-conducting channels in large water mines is technically difficult, and it is difficult to formulate mine water prevention and control schemes.In this paper, salt is selected as a tracer to study the hydraulic relationship between the main water inrush point of the mine and the karst channel exposed by the grouting hole through the connectivity test.Based on the calibration of the corresponding relationship between the conductivity of water sample and salt concentration, the proportion of the water inrush point in the supply water source of the karst channel is calculated.The test results show that the karst passage is well connected with the maximum water inflow point at -30 m level.The tracer recovery rate is over 88.45%, it can be judged that the tracer is the main recharge channel, but it has poor connectivity with the water inrush point at -70 m level.After the channel is blocked by the dropping aggregate+grouting, the water inflow at the -30 m level inflow point decreased from 24 000 m³/d to 500 m³/d.The mine drainage costs have been greatly reduced, and safe production has been guaranteed.The research results show that the connectivity test has good applicability in the exploration of the water guiding channel of the karst pipeline filling mine, and it is a reliable technical means to find out the connectivity and recharge of the water guiding channel and the mine gushing point.It can provide effective technical basis for the prevention and control of water in Dashui mine and avoid blind construction caused by unclear conditions, which has significant economic and social benefits.