Abstract: To overcome disadvantages of the conventional cement-soil mixed column installations, which often led to the poor integrity and uneven strength of the cement-mixed columns, a new three-dimensional cement-soil mixed (TCM) column system was developed, and the associated installation procedures were introduced. Combined with the standard penetration test (SPT), low stress integrity testing as well as laboratory unconfined compressive strength tests, the properties of TCM column and conventional cement-soil mixed column were comprehensively and comparatively evaluated. Results indicate that the installation procedures of the TCM column can overcome the slurry overflow phenomenon, which is one of the most important disadvantages in the conventional cement-soil mixed column installation. In addition, the quality of the TCM column is much better with coring sample rates exceed 90% for all the cases studied. Thus, the integrity grade of the TCM columns can be classified as Grade I, where the integrity and strength of the TCM column are much better than that of the conventional cement-soil mixed columns. In addition, the low counts of the standard penetration test and the unconfined compressive strength are increased significantly with the increase of the cement mixing ratio, but irrelevant to the water-cement ratio.

Key words: TCM Columns, Installation Procedures, Standard Penetration Test, Low Stress Integrity Testing, Unconfined Compressive Strength