Study On Factors Influencing The Strength Of Lime-stabilized Soils And Their Appropriate Compaction Water Content

The research of this thesis is served for the construction of Ninghuai Expressway. Based on the analysis and experiments of the engineering characteristics of lime-stabilized soils in China and abroad, compaction tests, unconfined compression tests, CBR tests have been completed for the natural soil and lime-stabilized soils from Ninghuai Expressway project. The compaction characteristics have been analyzed by compaction tests. The influence factors on the strength of lime-stabilized soils have been discussed from soil mass, hydrated lime dispersion and sampling water contents. Two methods for determining appropriate range of sampling water contents for lime-stabilized soils have been developed in this thesis.The following conclusions are obtained from the research of this thesis:Dry densities of compacted lime-stabilized expansive soils are insensitive to the change of water contents. Maximum dry densities decrease continuously with the decrease of lime contents. Maximum dry densities decrease sharply in the range of 0~3% of lime contents and gently for the lime contents above 3%. Optimum water contents of lime-stabilized expansive soils are not easy to determine exactly because of the gentle compaction curves.For specimens of 5 days' conservation, the smaller the soil masses are, the higher the strength of lime-stabilized expansive soils are. Hydrated lime dispersion have slight influence on the strength of lime-stabilized expansive soils when lime contents are less than 7% and have significant influence on the strength of lime-stabilized expansive soils when lime contents are more than 7%. Sampling water contents have a strong relation to the strength and mechanical properties of cyclic wetting and drying of lime stabilized expansive soils. For better quantities of road bases, such stabilized soils should be compacted at appropriate water contents.The determination of the compaction water contents according to the optimum water contents obtained from compaction tests can not be acceptable. The following methods are developed in the thesis.1. Use compaction curves, the relationship between sampling water content and strength to determine the range of compaction water contents.2. If W represents water content where the dry densities begin to decrease sharply (the soils are nearly saturated), the appropriate range of compaction water contents is approximately (W-3, w) for soils with lime additive amounts in 4%~13%.