Research On Techniques Of Top-down Construction Method In Soft Soil Region

Top-down construction method has been widely used for tall building in soft soil region, but because of the limited bearing capacity of pile in soft soil, the construction speed of structure above ground is limited, while the basement is constructed reversely.In this paper, the feasibility of pile with high bearing capacity, such as post-grouting bored concrete pile, pedestal pile, huge pile and so on, used in top-down construction is studied. The construction speed increase of structure above ground is proved to be available when those high bearing piles are used in top-down construction, both in the vertical load transition system of one column over one pile and one column over several piles. The key techniques of top-down construction, such as uneven settlement of piles, the connection of beam and column and plate and wall, are summarized and given. Due to the great importance and complexity of general construction plan for tall building using top-down method, some basic rules, such as the combination and dividing line between top-down method and tradition method, the excavation method and so on, are suggested.