Abstract: To examine the effects of fluid pressure on effective properties of solids with closed pores,a new micromechanical model has been developed to investigate the coupling effect between the macroscopic deformation and the pore pressure.In the proposed micromechanical model,the internal pressure is generated by applying eigenstrain in the domain occupied by the fluid phase.The effective properties have been obtained with the use of Eshelby-Mori-Tanaka equivalent inclusion method.Analytical results are verified against those from finite element solutions and a good agreement is achieved.The results show the overall effective bulk modulus depends on the property,the volume fraction and the internal pressure of fluid inclusions.The fluid pressure can strengthen the overall effective bulk modulus,but it has no contribution to the overall effective shear modulus.