Research On Mechanics Experiment And Micro-Structure Characteristics Of Light Weight Soil Mixed With Foam

Lightweight foam mixed soil is mainly a mixture of lightweight materials EPS foam, a curing agent cement and undisturbed soil.In this thesis, fiberis added tothe lightweight soil in order to enhance the toughness.Up to now, the research on light soil with fiber is less, and the related theory of light soil is not perfect, which limits the wide application of the lightweight mixed soil. With the help of laboratory tests, the shear behavior, compression properties and microscopic characteristics of lightweight foam mixed soil are studied. Specific results are as follows:1.Light weight material EPS can reduce the bulk density of light weight soil. The mass reduction of light soil is not obvious when the content of the EPS is less than 1%. When the content is more than 5%, the production of light soil samples is difficult and the solidification of cement is difficult to keep the soil structure from incompact when the mechanical properties of light soil decreased significantly. Accordingly, the content of EPS should be appropriate.2.The quality of light soil decreases while its shear strength decreased with the increase of EPS content. Light soil shear strength values improved significantly when the cement content increased in the higher range. Light soil shear strength and toughness are improved with fiber content increased.3.The change of content of EPS, cement and fibers do not result in light soil internal friction angle much impact. Light soil cohesion becomes smaller when the EPS content increased while increasing the fiber content or cement content causes light soil cohesion increased. All the three are to change the shear strength of the lightweight soil by changing the cohesive force.4.The strain of light soil increases with the increase of EPS content. The increase of fiber or cement content makes the strain of lightweight soil decrease, which is more obvious in the high content of fiber and cement. The compression modulus of lightweight soil decreased with the increase of EPS content while it is increased with the increase of cement or fiber content. The compressive yield stress of lightweight soil increased with the increase of the content of cement or fiber. When the EPS content is increased, the yield stress of lightweight soil is reduced.5. The micro morphology of the light soil changed after the addition of cement. The flake soil particles is connected by the water chemical reaction and they become an integral connected from the superposition cover, which reduces the pores between soil particles. When the content of EPS increased, the microstructure of the light soil skeleton varies little and the condensation effect between EPS particles and solidified soil is reduced. Cement production of the aggregate effect is stronger and the overall and structural properties of light soil is also stronger in higher cement content of light soil. The mechanical properties of lightweight soil are better in macroscopic view.