Abstract: The optimum cement content for the deep excavation in soft soils improved by the cement mixing method is usually selected by the experience and no technical bases are followed. This paper presents the results of the cement mixing research results. The unconfined compressive strength, cohesion, internal friction angle, deformation modulus of the soilcement mixing samples with various cement contents are studied. The lateral deflection of the deep excavation structure, ground subsidence with various cement content are numerically simulated. The results indicate that, the maximum lateral deflection the supporting structure and the ground subsidence reduce with the increase of the cement content. The soil improvement effect is also increase with the cement content. The laboratory study results were used in a soft soil deep excavation improvement project in Fuzhou and the results are satisfactory.

Key words: Foundation Excavation, Soil Improvement, Cement Ratios, Deformation, Construction Safety