PURPOSE: To enable a quick execution and to prevent the sliding of ground at a boundary portion between banking and non-banking by using a rigid permeable pile as a drain material.

CONSTITUTION: A rigid permeable pile 1 is driven into a poor subsoil 5. The pile 1 is not driven up to a bearing ground layer 4, and it is such a degree of friction pile that it reaches the bearing ground layer 4 at a point that planned consolidation terminates. In such a state, banking 3 is made on the surface of the earth, and when uniform load is applied thereto, the surface of the earth and vicinity is more quickly consolidated than a deep seated section, and the displacement also increases, so that shearing stress τn in intended to push-down the pile 1 is applied to the pile 1. Over against that, the consolidation does not so progress in the deep seated section, so that the shearing stress τp in the reverse direction acts. As the result, a pressure bulb 6 takes place, and the stress is transmitted to the deep seated section to accelerate the consolidation.