Efficiency of Buttress Walls in Deep Excavations

Shong-Loong Chen ； Cheng-Tao Ho ； Chong-Dao Li ； Meen-Wah Gui

《Journal of GeoEngineering》 6卷3期 (2011/12) Pp. 145-156

https://doi.org/10.6310/jog.2011.6(3).4

並列摘要

Buttress walls have been widely adopted, with many successful cases, in soft ground excavation work. The field instrumented displacement data indicated that buttress walls could effectively reduce the lateral displacement of diaphragm wall and thus enhance the stability of the excavation work. The interaction between the soil/buttress- and diaphragm walls is a three dimensional problem but in practice, due to the complexity of three-dimensional analysis, the problem is commonly simplified into a two-dimensional problem. The simplification becomes irrational if the excavation site is almost square. This study aimed at examining the influence of the geometry of the buttress walls (shape, thickness, and length) on the displacement of buttressed diaphragm wall via a series of three-dimensional analysis. The relative effectiveness of the internal and external buttress walls and of the chipping-off and non chipping-off buttress walls on the displacement of the diaphragm wall were also studied. The numerical procedure was first calibrated against the field data obtained from the Taipei 101 and Neihu basements excavation projects. These results were evaluated and compared through the so-called displacement reduction ratio (DRR). The results indicated that the effective spacing of the buttress walls should be within two times the excavation depth and that the T-shaped buttress wall was more efficient than the I-shaped buttress walls. In addition, to achieve optimum performance in minimizing diaphragm wall displacement, the buttress walls should not be sequentially removed during the excavation stages.

並列關鍵字

Soft ground excavation ； buttressed diaphragm wall ； wall displacement ； three-dimensional FE analysis