Studying On Strength And Deformation Of Fiber-reinforced Expansive Soils

Recently, with the development of improved technologies of expansive soil, many people of geotechnical engineering pay much attention on Fiber reinforced expansive soils. The characteristics of expansive soils can be changed with a effective way, Which does not affect the nature of expansive soil or pollute the environment because of its unique advantages. In this paper, the strength, dry-wet cycles and deformation of expansive soils and fiber-expansive soil under pressure was studied. The main research contents are as follows:(1)Different length and content of polypropylene fibers was put in expansive soil. The effect that fiber caused on cohesion, internal friction angle, Unconfined compressive strength as well as Swelling deformation of expansive soil were got; Strength, the specimen destruction of expansive soil was compared with the fiber expansive soil, and the result shows that different length , content of fiber causes much impact on the strength and deformation of expansive soils . Fibers can also increase fiber peak strength of expansive soil, reduce the loss of residual strength of fiber-reinforced expansive soil , increase the toughness of soil damage, and delay damage of fiber-reinforced expansive soil , increase the toughness of soil damage, and delay damage.(2) Length of 12mm, content of 0.3% polypropylene fiber was added to the expansive soil, and we get many results which are the strength degradation, the development of crack and the relationship between the strength and times of dry-wet cycles. The cohesion the fiber adds to expansive soil is an incremental, and this incremental does not change with wet and dry cycle.(3)According to the deformation of expansive soils and fiber-expansive soil under pressure, the Inhibitory effect that the fiber caused on expansive soil was very clear. The results show that the expansion of internal force and expansion on rate degrade.