Some insights into wet soil mixed properties from a database developed through routine project work

Current good practice guidance and codes of practice for soil mixing typically focus on strength as the primary criterion for achievement of project specifications. For example, correlations for stiffness with strength are commonly used in lieu of direct measurements. Long-term consolidation or creep of mixed soil is rarely measured in practice, either in the laboratory or in the field with the exception of a small number of good-quality case studies. This paper presents some insights into mixed soil properties, which are not routinely measured or specified as well as strength, gleaned through the course of normal project work where the overall concept required mixed soil properties other than strength to be measured. All data was taken from wet soil mixing projects which involves the introduction of cementitious grout under medium or high pressure in conjunction with mechanical rotavating of the soil. The projects include both mass mixing and deep soil mix columns using proprietary technologies briefly described in the paper. All projects forming the database were undertaken in the UK.