| Summary: | 碩士 === 義守大學 === 土木與生態工程學系碩士班 === 94 === Compaction is one of the common methods used for soil improvement. The basic concept of compaction is imposing energy onto the soils in order to make the soils densified so that the properties of soils are enhanced. There are two different compaction methods,namely shallow and deep compaction. Shallow compaction is basically using the rolling machines to compact the soils by layers. Usually shallow compaction is widely used in the civil engineering, for examples the road engineering; runway of the airports; retaining walls and clay liners of the waste repository etc. This research is aiming on the study of influence of shallow compaction on the properties of soils.
The objects of soil improvement include the increase of shear strength; decrease of the compressibility; control the permeability and reduction of the potential of liquefaction. The factors affecting the compaction consists of soil type; water content; compaction method and compaction energy etc. The way controlling the quality of in-situ compaction depends on the relative compaction, which is determined by the maximum dry density from the compaction experiment in the laboratory and the in-situ dry density in the field after compaction. In order to get higher relative compaction, compaction with high energy is usually adopted in the field. Although compaction with high energy is indeed making soils more densified, the microstructure of the clay soils makes the transition from the random flocculated structure to the aligned dispersed structure, which would therefore reduce the shear strength and increase the compressibility. In other words, compaction with high energy makes the compacted clay soils even worse. This is so called over-compaction.
The main objective of this research is to study the influence of compaction energy on the shear strength; compressibility and permeability of clay soils. In this research, different compaction energy will be adopted in the compaction experiments in order to study the properties of clay soils. This research is very helpful on the control of the quality of compaction in the field.
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