Abstract: How to deal with the waste soil is a difficult problem in the large deep excavation projects. It is particularly difficult to excavate and reuse the shallow soil in coastal areas. This paper presents a case history of an airport engineering project in Tianjin. A large number of tests were performed on the samples of Tianjin Binhai soft soil with depths less than 15m and mixed with slaked lime. Based on analyzing the basic properties of the natural soil, the compaction characteristic of soil samples containing 0%,8%,15% and20% slaked lime was discussed. Meanwhile, the consolidated quick direct shear strength and the unconfined compressive strength of soil samples with various mixing lime ratios and degrees of compaction of 0.90, 0.93 and 0.96 were studied. The strength characteristics of the Tianjin Binhai shallow soil mixed with the slaked lime are further evaluated. It provides a reliable reference for the design and construction, when the shallow soil from the deep excavation uses in the site backfill, road backfill, and utility trench backfill.

Key words: Shallow Soils, Lime Treated Soils, Degree of Compaction, Mixing Ratio, Strength Characteristics