The purpose of this report is to summarize the current status of mixing and mixer development, particularly the aspects of the principles employed that may lead to more efficient designs and techniques for incorporating potential stabilizers in wet, fine-grained soils. The report points out the advantages and limitations of presently available items of equipment, discusses factors contributing to the efficiency of mixing, and presents the findings of laboratory mixing investigations. The information presented herein was obtained solely from available technical literature. Only material published in or translated to English was reviewed. Although numerous investigations have been made and reported by many individuals and organizations, very little of the work involved fine-grained soils under wet conditions similar to those which would probably be encountered during military operations in forward areas. In the few instances where mixing of wet, fine-grained soils has been investigated, the studies were conducted primarily on a laboratory basis.

A review of literature on soil stabilization by electrical methods is presented, with particular emphasis on the technique that might be applied by the military to improve mobility of surface vehicles over very wet and unstable fine-grained soils. The mechanics of the phenomenon of electroosmosis of soils are described, and the quantitative expressions for electroosmotic flow based on the theories of Helmholtz-Smoluchowski and Schmid are compared. It is apparent that the applicability of the theoretical concepts and their validity in relation to practical engineering problems remain to be established. Based on accounts of numerous successful practical field operations, it is known that certain definite benefits are derived from the application of an electric current to wet, fine-grained soils. In addition to enhancing drainage of soils of relatively low permeabilities, the process of electroosmosis results in a consolidation of the soil that contributes to an improved strength and stability. It has been demonstrated that an irreversible electrochemical hardening of soils containing clay occurs when aluminum electrodes are employed in the electroosmosis process. This phenomenon has resulted in the development of techniques for increasing the bearing capacity of piles, and has been explored for its possible applicability in soil reclamation and chemical injection processes.