Study On Calculation Method Of Well Considering Impervious Structure Of Foundation Pit

Well is an important measure to control seepage,and it is widely used in dewatering of foundation pit,drainage and decompression in earth dam and embankment,hydrogeological data survey and so on.Incomplete wells are widely used in practical engineering,and if both ends of the filter tube are not at the aquifer level,conventional methods cannot be directly used.At present,there are few researches on the simplified calculation method of the well considering the influence of foundation pit's impervious structures.In the actual situation,there are many suspended impervious structures,or impervious structures with leaks,and they cannot be directly applied to image method as a complete barrier.In this case,the calculation of the well,determination of hydrogeological parameters and detection of impervious structure's water stoppage effect are much more complex.In view of the above problems,the following research works are carried out in this paper:(1)The simplified calculation formulas of the confined wells at home and abroad are summarized.Improving the conventional method,and the axisymmetric FEM program are used to perform the analysis and verification(2)Considering the integrity of impervious structures,the permeability coefficient,the hydrogeological parameters,the relative position and the type of well,the simplified calculation method of the well is put forward.(3)Aiming at the effect of impervious structures on pumping test,a simple and feasible research method for determining aquifer's permeability coefficient and impervious structure's water stoppage effect is proposed.(4)The reasonableness of the simplified calculation method is verified by comparing the results of the simplified calculation with the the results of seepage analysis FEM progaram.