Field experiments on triaxial mixing pile reinforcing the extra-deep starting and ending well of shield tunnel

Shield excavation starting and ending is the important thing for shield tunnel, which more attention should be paid to. Therefor, field experiments on the triaxial mixing pile have been made in the reinforced engineering for shield excavation starting and ending of Wuxi city. The experiments explore the both of mixing control and effectiveness tests. Mixing control should have a focus on cement adding contents, water-cement-ratio of cement paste, and the matching relation between the cement paste flow and drill pipes´ speed. Effectiveness test should have a focus on uniformity, unconfined compressive strength testing in the laboratory and the impermeability of pile samples. And the triaxial mixing pile drill and cutting tool has been improved, which enhance the efficiency of drilling. The results have directive value to the reinforced engineering for shield excavation starting and ending of Wuxi city.