Abstract: A composite structure-internal liquid element is proposed in this paper. Through the use of analytical functions in two orthogonal directions. the three-dimensional problem of coupled structure-internal liquid vibration is reduced lo a one-dimensional one, resulting in a drastic reduction in computing efforts.Cylindrical and conical frusium composite elemenls are proposed lo suit different problems. and examples are presenled to demonsirate the accuraey of the method.

Key words: mixture theory, unsaturated soil, entropy inequality, constitutive equations, field equations