The effect of anisotropy on the pore pressure development for clay is investigated. A rotational yield surface is presented by introducing the Sekiguchi-Ohta stress ratio and Xin’s failure equation into the Modified Cam Model; and an anisotropic elastoplastic model is built. Based on this model

a new anisotropic pore pressure equation is presented

which can account for the pore pressure development induced by the rotation of Lode angle and principal stress. The equation is used to study the pore pressure development induced by the rotation of the Lode angle and stress axis direction under triaxial stress state. Finally

the pore pressure development in the plane strain anisotropic clay foundation under an strip load is analyzed by the equation. Results show that the pore pressure induced by the Lode angle rotation is small in the foundation. However

in the soil under the edge of load

pore pressure induced by the rotation of stress axis direction is significant

especially at a lower depth.