Estimation of compressive strength of cement-treated marine clays with different initial water contents

A formula to estimate unconfined compressive strength of cement-treated marine clays is proposed. The formula has a form similar to the gel–space ratio theory. In the proposed formula, the strength of cement-treated soil is given by volumetric solid content, strength increase coefficient due to cement, exponential parameter N representing the effect of the void structure of soil and cement content in respect to the solid material of soil. The formula was adapted to the results of laboratory strength tests of cement-treated soils made of six dredged marine clays with different levels of initial water content. The strengths estimated by the proposed formula agreed with the measured strengths fairly well, using the parameter N=3.5–4.6. The formula was applied to the strength estimate of foam- and bead-treated soils made from dredged marine clay, using the parameter N=2.1–2.5. The applicability of the proposed formula was examined with the results of strength tests carried out for the design of cement-treated soil for the construction of D runway at Tokyo’s Haneda Airport. Seven samples collected in the construction sites were mixed with different amounts of cement and the different levels of initial water content. On fitting the proposed formula to the results of all the data, the proposed formula estimates the measured strength well. On comparing the estimates with those using a conventional formula based on the water–cement ratio, the proposed formula generated better-fit estimates.