Prescription Formula of Foamed Particles in Lightweight Soil

To research the prescription of lightweight soil under an optimum water content condition, the influence of the water content on the material state should be completely removed. The optimum water content of different mixing ratios of lightweight soil can be obtained using the optimum water content model. The prescription formula and prescription optimization method of foamed particle lightweight soil were investigated using density tests and unconfined compressive strength tests. The results show that the density of lightweight soil is mainly affected by the content of expanded polystyrene (EPS) particles, and it decreases linearly with an increase in the EPS particle volume ratio. However, the effect of the cement content on the density of lightweight soil is very small and can be ignored. The unconfined compressive strength of lightweight soil increases linearly with the increase in cement content, and the strength growth rates are mainly affected by the different EPS particle contents. There is a minimum cement content; if the cement mixing ratio is lower than the minimum cement content, there will be no solidification effect for the cement. The unconfined compressive strength of lightweight soil decreases linearly with an increase in the EPS particle volume ratio, and the strength reducing rates are mainly affected by the different cement contents. There is a maximum content for the EPS particles; if the EPS particle volume ratio is more than the maximum content of EPS particles, the strength of the mixed soil will be completely lost. Considering the density, strength, and cost of mixed soil, two empirical prescription formulas were proposed: the positive correlation linear fitting method and the negative correlation linear fitting method.