Design and Construction Aspects of Soil Cement Columns as Foundation Elements

Engineers have been finding increased application for soil cement columns on several projects in the United States. Most of the application has been in the areas of excavation support and the control of groundwater seepage. There has been very limited application in the area of foundation support for structures primarily because of the lack of established design and installation criteria. In 1997, the Japan Building Center issued a publication containing guidelines for using soil cement columns as foundation elements. These guidelines were based on data, including some from load tests, gathered over a period of about 15 years from about 9,000 projects where soil cement columns were used as foundation elements. In this paper, design procedures based on the Japanese guidelines, with particular emphasis on designing for earthquake loading are introduced. A design level or design base earthquake is considered. The design procedures are described for individual soil cement columns, soil cement columns spaced in a group, and for soil cement columns tangential or secant to each other in a group. A proposed quality control program that should lead to the establishment of appropriate installation criteria is also introduced. The design and installation aspects presented in the paper should advance the cause of soil cement columns as economical alternatives to conventional foundation elements.