Unified approach to ground improvement by heavy tamping

Abstract

A world-wide review of heavy-tamping projects indicated that highly organic clays, which due to their secondary compression characteristics may not be amenable to treatment by surcharge and vertical drain installation alone, can nevertheless be stabilized by applying high-energy impact on installed dynamic replacement (DR) sand columns using a conventional dynamic consolidation plant. Field trials were thus conducted to enforce primary, as well as to negate secondary, compression of in-situ peaty clay deposits by this form of treatment application, in the course of which dynamic replacement and mixing (DRM) of such soils with sand charges was originally identified as a distinct ground-improvement mechanism. From the field results and review, it is also perceived that ground-improvement mechanisms resulting from the application of a wide variety of heavy tamping plant and procedures to soils ranging from granular to highly organic cohesive materials may be generalized on a common physical basis. Further, unique relations may apparently be construed between alternative measures of degree of ground improvement on the one hand, and a collective term incorporating initial soil consistency and standard operational parameters of ground treatment on the other, thereby providing a basis for rational performance design.