Experimental Research On Lime Treated Expansive Soils Used In Filling Of Embankment

Subgrade soils of HEFEI North Circle Freeway are recognized as problematic soils since they exhibit low strength, high swell and shrinkage characteristics. These properties weaken the subgrade and cause severe damage to the pavements and it display high swell potential under high degree of consistency and the expansive soils with lower volume change potential maintain the CBR values very lower than the request of minimum strength for the fillings used in embankment of highways. According to the problems in present research, the aim and plan of this task are proposed.For discussing the feasibility and effect of lime improving expansive soil, and in order to offer parameter for engineering practice, the author conducted a mass of laboratory experiments. In these experimental programs, the strength, swell and shrinkage characteristics of the soil and the soil treated with lime were evaluated based on the normal experiments used to test the soil. In view of the bad characters of expansive soils filler, this paper designs physical property tests, strength-mechanics tests and swelling-shrinkage tests for lime-treated soil, especially the influence of initial state parameters (water content and dry density) and different testing conditions on swell percent, swelling pressure, CBR value and modulus of resilience. Together with the theories of unsaturated soil, experiments were designed to research the impact of lime treated expansive soils. And some significant fruit is obtained. Base on the investigation results, the concept of the initial physical state or the consistency is developed, and then the initial consistency is discovered to have a significant relationship with swelling and strength characteristics. The results of study indicate that adding lime into the expansive soil can reduce the content of clay gain obviously, reduce the plasticity notably, increase the strength greatly, and control the property of swelling and shrinking.Low dose lime provided effective treated by strength and reducing the swell and shrinkage potentials in embankment for the construction of expressways. it can been accepted for the compacted expansive soil mass that decreasing the volume change potential with proper increasing its water content and decreasing its consistency. Additionally, the effect and criterion of lime treated expansive soils can be decided from swell potential and strength.