Abstract: With the urbanization of cities, more and more construction related concerns, such as, lack of construction space, interfering with underground utilities and lack of sufficient tool characterizing the newly filled soils, become increasingly important. Facing these problems, the traditional approaches to the design and construction will likely lead to an unnecessarily conservativism, longer construction period and high cost in order to address the safety issues during the construction. This paper presents a case study of using the grouted steel tube reinforcement as the supporting system of a deep excavation in the newly filled soil layers. The guidelines for the borehole advancement, water ratio of the grouting slurry, grout quantity and the grouting pressure are discussed in the paper. Throughout the laboratory testing, it is concluded that the liquid glass solution can effectively adjust the viscosity of the grouting slurry. The viscosity of the grouting slurry is approximately proportional to the content of the liquid glass. The global stability of the excavation supporting system can be checked with strength reduction method.

Key words: Double-Solution Grout, Grouting Tube, Deep Fill Soils, Deep Excavation