Up to now

dewatering applies more and more in kinds of works; and a set of design and construct methods form. However

few people study the analysis of the dewatering effect. Large scale numerical model research carries out for the dewatering drainage engineering in a certain open coal mine excavation. Based on the hydrogeological condition

a reasonable numerical model builds up by using Modflow

and it is analyzed the detail dewatering effect under different conditions. Actual calculation results show that the dewatering effect influences greatly by factors such as the time of wells added

the single well pumpage

the amount and array of the wells

and the interaction among the wells

etc. Batch & time-sharing

wells array optimizing and single well pumpage adjusting are the most important influence factors of the optimized design and the design measure to enhance the water lowering effect. The action rule of these factors will provide some essential bases for the dewatering design and construction and actual engineering effect.