ABSTRACT
In Sec. 6.9 we saw that, in general, any undrained loading or unloading will create excess pore pressures ū in the region of the loading. These excess pore pressures may be positive or negative with respect to the long term steady state pore pressures u ∞ and they give rise to hydraulic gradients that cause seepage flow. These seepage flows lead to volume changes that, in turn, are associated with the changes of effective stress as the excess pore pressures dissipate. As the excess pore pressure diminish the hydraulic gradients and rates of flow also diminish, so that the volume changes continue at a reducing rate. After a long time the seepage and volume changes will stop when the excess pore pressures and hydraulic gradients become zero and the pore pressures reach their steady state values.
