Abstract: The compressive strength increase of the cement-fly ash-gravel (CFG) columns after the installation is positively related to the age of the concrete in the CFG column. During the CFG column installation, the passive soil zone inside the excavated area is disturbed and has minimal strength. Further, the strength of the CFG column at its early age is low. These adverse factors induce negative impacts on the supporting structures and their adjacent environment. The different CFG column installation sequences along the deep excavation supporting structures, which are column installed one next to the previous column along the longer supporting side and the column installed by skip one column along the shorter supporting side, are simulated by the commercial finite element software MIDAS GTS/NX. The results indicate that, the CFG column installed by skip location along the shorter side has less horizontal deflection in the supporting structure and less ground subsidence behind the excavated area. Further, the skip column location installation has only one day loner than the other method, but it is more reliable and less disturbance to the adjacent environment. Therefore, the skip column location method was recommended as the actual construction installation plan.

Key words: CFG column installation, numerical simulations, deformation analysis, construction plan