The drainage hole is an important seepage control measure

so it is one of the key problems to simulate the effect of the drainage hole in the seepage analysis. Although the substructure method is an effective and popularized method

its mesh generation

which is dependent on the global mesh

is still a difficult task in engineering practice. A novel method named superposed element method (SEM) is proposed to simulate the drainage holes. Firstly

the structure containing drainage holes is divided into two independent meshes. One is the global mesh without drainage holes

and the other is the local mesh of the drainage hole together with its adjacent zone. Then

the two independent meshes are coupled together through the virtual seepage on the outer interface of the local mesh. Finally

two numerical examples are studied

in which the effect of the drainage holes can be simulated accurately. According to the results of the sensitive analysis

the proper range of the local mesh is 1–3 times of the element length in the global mesh; and the permeability coefficient of the outer interface is suggested to be 102–103 times of the material permeability coefficient. Since the mesh generation of the superposed element method is quite simple

the new method is expected to be widely used to solve complicated seepage problems in engineering practice