Fig. 9 demonstrates that the ratio, eot /Aw, has fairly combined
together the effects of total clay water content, cement content
and curing time on the unconfined compression strength of
cement-admixed clay. The values of eot of each sample shown in
Figs. 5(a–c) were calculated using Eq. (2) with measured values
of vt, Gst, and gt. Also plotted in Fig. 9 are data from field coring
samples obtained in the core of full-scale deep mixing method
(DMM) soil-cement piles installed in Ladkrabang-Bang Phli in
the east of Bangkok metropolis, Thailand (Fig. 1) for the construction
of Highway No. 3256 (AIT 1998). Although the sites of
the field coring samples are different from that of the base clay
utilized in laboratory tests, the clay deposit at these sites is basically
the same, i.e., the soft Bangkok clay. Though the parameter
eot is deemed to reflect not only the total clay water content sCwd
and curing time but also the cement content sAwd, the inclusion of
Aw in the ratio eot /Aw is due to the following events. First, the
specimens with different cement contents can have the same void
ratios after curing depending on the total clay water content
present during mixing, but may possess different levels of
strength. Second, even though the samples have the same cement
contents but different total clay water contents, they may still
possess different levels of strength. The effectiveness of the
eot /Aw ratio is further proven in Fig. 9 where the unconfined
compression strengths of both field and laboratory samples reasonably
follow a unique relationship with the eot /Aw ratio. Therefore
even though the experimental and field data are limited and
based only on a single clay deposit (soft Bangkok clay), the following
relationship has been derived to describe the unconfined
compression strength of any cement-admixed clay: