EXPERIMENTAL STUDY ON UNCONFINED COMPRESSIVE STRENGTH OF SOIL AND EPS PARTICLES MIXTURES

This paper aims to study the density, strength and deformation characteristics of soil and EPS particles mixtures that is a type of light weight soil. It carried out the density tests and unconfined compressive strength tests of the mixed soil with different cement content, EPS content, age and water content. The results show the following findings. When volume ratio of EPS particals is 20% to 60%, the density range of the light weight soil is about 0.64g·cm^-3~1.46g·cm^-3. The amount of EPS particles has the greatest impact on the light weight soil density. When the volume rate of EPS particles is increased by 10%, the density of EPS particles light weight soil is decreased by about 0.15g·cm^-3~0.23g·cm^-3, which shows that it is feasible to realize the light weight of mixed soil by adding EPS particles. Cement content and water content have less influence on density of light weight soil. But age has little effect on density of light weight soil. In addition, when the volume ratio of EPS is 50%, the density of light weight soil is similar to that of water. The range of unconfined compressive strength of EPS particles light weight soil in this test is 103.2 kPa~1359.0 kPa, while the unconfined compressive strength of plain soil is 79.98 kPa. So it can be stated that the light soil in the proportioning of this test has better strength properties relative to the plain soil. The unconfined compressive strength of light weight soil increases exponentially with the increase of cement content. However, the larger the volume ratio of EPS particles, the smaller the unconfined compressive strength and the linear relationship between them. In the case of more than the optimal water content, with the increase of water content, the relationship between the unconfined compressive strength is reduced exponentially. The increase of age makes the unconfined compressive strength increase in hyperbolic form. The stress-strain relationship characteristics of EPS particles light weight soil are mainly characterized by strain softening type. However, the increase of water content and the increase of the content of EPS particles can make the stress-strain relationship curves of the light weight soil change gradually to the hardening type. Damage strain and average deformation model are used to describe the deformation characteristics of soil. The damage strain of light weight soil decreases with the increase of cement content, but the volume ratio of EPS particle is opposite. The greater the water content, the greater the damage strain of light weight soil. However, the increase of the age makes the damage strain of the sample decrease. When the volume ratio of EPS particles is more than 50%, the damage strain of light weight soil is greatly increased, and its brittleness is obviously weakened. The average deformation modulus is a parameter to characterize the stiffness of EPS particles light weight soil. The larger the cement content, the larger the average deformation modulus of light weight soil. However, the average deformation modulus of light weight soil decreases linearly with the increase of the volume ratio of EPS particles. The increase of water content can reduce the stiffness of light weight soil, and the longer the age, the greater the stiffness.