Soil nailed structure has been proved to be a type of economical and effective excavation support system and played an important role in geotechnical engineering. But it is mostly used in such type of soil as sand, silt and stiff clay and seldom used in soft clay, especially in saturated mucky clay. In this paper, two soil nailed structures recently constructed in soft clay in China are introduced. A new method so-called Secondary Grouting is applied in one of the projects firstly. THe results of the field pull-out test indicates that the new technique can increase the lateral resistance of bars efficiently. The horizontal displacements are measured durign construction. It has been shown that the critical factors affecting the horizontal displacement and stability of the structure are the design parameters, the excavation sequence, the excavation depth and the construction time. It is important to set the steel bar in time after excavation to decrease the horizontal displacement. Finally, the conclusion is drawn that soil nailed structure can be used in soft clay.
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