Publication Abstract

Grouting and Ground Treatment: Proceedings of the Third International Conference, (ASCE)

Strength Properties of Soil Cement Produced by Deep Mixing
Osamu Taki

Among many soil mixing systems, the most common is the deep soil mixing system that uses cement slurry as an additive reagent. This is because, 1) relatively simple equipment is needed, 2) satisfactory mixing is available, and 3) quality control is not difficult. At the present time, however, strength properties of soil cement produced by deep mixing methods is not well understood. For example, their relationship with mixing methods is not well established nor is the concept of uniformity of soil cement. Strength test data of soil cement cores from two project sites were obtained with cooperation from the project owners and specialty contractors. The projects involved two deep mixing systems using cement slurry; the multi-shaft CDM (Cement Deep Mixing) and the single-shaft SBM (Shear Blade Mixing) systems. The first project is the soil improvements at Berth 55/56 at the Port of Oakland in California, which used the Cement Deep Mixing system. The second project is the foundation soil improvement of a six-story commercial building in Niigata, Japan, which used the SBM system. For these projects, many core samples of soil cement were obtained for quality control. The subject of this paper is statistical analyses of the strength test data of the core samples. Histograms were used to analyze the strength distributions. A method to determine the design strength is presented which utilizes the standard deviation and the coefficient of variation of the strength test data.

 article #1108; publication #62 (GRT-2003)