Coal Geology & Exploration


Dewatering from an aquifer bottom for drain and depressurization is one common method to ensure safety mining. This method is significantly different from pumping from the ground. In order to study the seepage characteristics of the dewatering hole(well), the seepage characteristics of a single well dewatering from an unconfined aquifer bottom was taken as an example and studied using numerical simulation method. The results show that when lw<lc, the pore water pressure above the dewatering well is greater than zero, which presents the rule of increasing first then decreasing from bottom to top, and the seepage flow increases with well length following an exponential function relationship. When lwlc, the seepage characteristics and seepage flow of the incomplete dewatering well is the same with the complete dewatering well. The seepage flow increases with the well radius following a power relationship with the exponent less than 1. By substituting s+lw into Dupuit formula for unconfined complete wells instead of drawdown s, a revised formula was proposed which could be used to calculate water flow for uncomplete dewatering wells with a more accurate result. This study will provide an important theoretical basis for understanding the seepage characteristics and more effectively drilling of the dewatering wells.


aquifer, dewatering well, seepage flow, Dupuit formula




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