METHOD FOR IMPROVING SOFT GROUND BY SAND DRAIN METHOD AND CYLINDRICAL BAG FOR USE IN SAME

摘要

Soft ground is improved by a sand drain method wherein a casing pipe is inserted in the soft ground followed by insertion of a cylindrical bag composed of a water-permeable material into the casing pipe; sand is filled in the cylindrical bag and then only the casing pipe is drawn out from the soft ground whereby a sand drain is constructed in the soft ground; and then, a load is imposed on the sand drain-constructed region to remove water through the sand drain and consolidate the soft ground. The diameter of at least a part of the cylindrical bag is capable of being increased when the consolidation load is imposed on the sand drain-constructed region.