Abstract：In seepage analysis using the composite element method(CEM)，the drainage holes are regarded as a kind of material with high permeability coefficient and are treated as“air sub-elements”contained in the conventional rock(soil) element，which is called“composite element”. By CEM，the drainage holes need not be meshed out and the mesh can be“coarse and random”，which makes the mesh generation work relatively convenient. As the conventional shape function of lower order is not accurate enough to simulate the strongly nonlinear flow field around drainage holes，the p-version adaptive algorithm is implemented in the CEM to get a better solution of the seepage field around the drainage holes. The p-version adaptive CEM can convert the complicated preprocess problem into a complicated computation problem. In this way，the mesh generation becomes less restricted；calculation mesh need not be regenerated when the design scheme of drainage holes is changed. Numerical example shows the advantages of the new CEM.
