Abstract

The composition of soft soil affects the ability to improve with inorganic binders (lime, cement). The report mentions the influence of the material composition of soft soil in the North Central coastal region on the ability to improve soil using the cement soil pile method in the laboratory. Research results show that grain size, salt content and organic content have a great influence on properties of cement soil piles. Among three types of soil with the same origin and different particle compositions: soft clay, soft sandy clay and soft clayey sand, the cement-reinforced clayey sand has the highest unconfined compressive strength and deformation modulus E50. The unconfined compressive strength and deformation modulus of mixture of cement and soft clay equals 49.0, 61.9% and 25.0, 39.6% as compared to of mixture of cement and soft sandy clay, cement and soft clayey sand. As the salt content and organic components increase, the unconfined compressive strength and deformation modulus decrease. As salt increases greater than 1%, the unconfined compressive strength and deformation modulus decrease from 10% to 30% compared to of the mituxe of the soft clay with cement. The unconfined compressive strength and deformation modulus of the cement reinforcement mixture with mud clay mixed with many organic content are only 33.5%, 58.1%, 51.0%, 76% compared to the values of the mixture of cement with mud clay mixed little organic matter and mud clay mixed with organic matter. Characteristics of unconfined compressive strength have a strong correlation with the deformation modulus E50. This result shows that when studying soft soils for cement pile, it is necessary to add additives or increase cement content for soils containing salt and organic matter.