Key technology of the top down construction method for oversize deep foundation pit

Abstract:

The foundation pit support works for the Wuhan Nanguo Center first phase project was constructed using the top down construction method, where the surrounding environment was complex, and the sand layer at the site is thick. The technical requirements for foundation pit design were high, in particular, the verticality of the diaphragm wall and column pile of the support structure was high with deep rock embedment. The soft and hard alternate formation tended to produce deviation during construction with low rock penetration efficiency. In view of the major and difficult points in construction, measures were taken from the aspects of equipment selection, process selection, bit selection, etc. to solve the difficulties in the construction of the super deep and large foundation pit support structure by the top down method. The approach to solving the problems was introduced, and significant results were achieved with the quality meeting the relevant technical requirements.