The influence of the degree of saturation on dynamic response of a cylindrical lined cavity in a nearly saturated medium

• Obtained the time-domain solutions for lined cavity in a nearly saturated medium.
• The influence of degree of saturation (Sr) is investigated numerically.
• The Influences of stress and displacement are found to be little as Sr=95–99%.
• The significantly influences are found when a small change of Sr (99–100%).

In most previous studies on the dynamic response of a long cylindrical cavity subjected to internal transient dynamic loads, the porous medium was usually assumed to be completely saturated by ground water. In practice, however, the full saturation condition does not always exist. In this paper the surrounding soil and the lining of the cavity are respectively treated as a nearly saturated porous medium and an elastic material, and the governing equations for the dynamic problem are derived. A set of exact solutions are obtained in the Laplace transform domain for three types of transient loads, i.e. suddenly applied constant load, gradually applied step load and triangular pulse load. By utilizing a reliable numerical method of inverse Laplace transforms, the time-domain solutions are then presented. The influence of the degree of saturation of the surrounding soil on the dynamic response of the lined cavity is examined for numerical examples.