Publication Abstract

Proceeding of the 2018 DFI-EFFC International Conference on Deep Foundations and Ground Improvement, Rome, Italy, (DFI, EFFC)

Unconfined Compression Tests of Cement-Treated Soil Containing Unmixed Soil
Tsutomu Namikawa Civil Engineering and Sae Suzuki

Cement-treated columns constructed by deep mixing method are likely to contain incompletely mixed material, that is, in-situ soils unmixed with cement. Such unmixed soil should affect the mechanical performance of the cement-treated column. This paper presents unconfined compression tests of cement-treated clay specimens containing unmixed clay. The specimens used in this study were prepared by mixing cement, water and Fujinomori clay in the laboratory. On the procedure of preparing the specimens, untreated clay pieces representing unmixed soils were intentionally inserted into the cement-treated clay slurry in the mold. The volumetric proportions of untreated clays are 1% and 2%, and the locations of those are determined randomly. The test results indicated that the untreated clay considerably affects unconfined compressive strength (UCS) of the cement-treated clay. UCS of the specimen for the untreated clay content of 1% is reduced by about 9% as compared to that of the specimen without untreated clay. UCS of the specimen for that of 2% is reduced by about 13%. This experimental result indicates that the influence of unmixed soil cannot be neglected when determining the design strength of the ground improved by cement mixing method.

 article #3067; publication #1040 (ROME-2018)