Engineering Application Study On Lime Modification Expansive Soil

Lime has a distinct effect on expansive soil. Lime stabilized basement has many merits, such as higher strength, better water stability, lower construction price and convenient construction mathod. Lime stabilized basement is now widely used in high class highway sub-base, but the study on how the lime works and what the effect is if lime is added into expansive soil is not systematicly and comprehensively showed. Combining with some real engineering problem in the Nin-Huai expressway construction, the paper studies the mix design and the engineering application of lime modification expansive soil.As large area of expansive soil has been found along the line of Ning-Huai Expressway, the danger arosed by the ground base made by expansive soil must be analysed firstly. The problems existing in the process of constructing expressway basement with expansive soil are presented and discussed in this thesis. Laboratory experiments have been done on representative samples from Huai'an region of Ning-Huai Expressway. The different engineering properties between original state expansive soil and lime modification expansive soil are studied systematically through indoor experiments and on-site estimation based on different kinds of soil samples. The main contents are followed:(1) Analysing the basic engineering properties of the original state expansive soil and the change rules when lime is added into the plain soil, including the distinguishing methods of the original expansive soil, the influence factors to the maximum moisture density and optimum moisture content tested by different kinds of indoor experiments (dry compaction experiment or wet compaction experiment) of soil samples, etc.(2) Studing on the changing rule of lime modification expansive soil, such as free swelling ratio, swelling strength, non-side limitation compressive strength.(3) Detecting the changing rule of lime modification expansive soil when the temperature is low in considering the temprature condition and constructing condition.(4) Establishing the constitutive law of lime modification expansive soil by the methods of making the remaking soil samples and analyzing the relations of the soil samples under different stresses and different strain.(5) Putting forward some advices aiming at the unsolved problems in the expressway basement construction on the basis of theory combining with practice.The paper's conclusion will provide some theoretical value and may give some directions for the experiment study and the application of lime modification expansive soil.