Abstract:

The south of north exchange hall of Military Museum Station on Line No. 9 of Beijing Metro is adjacent to Fuxing Road and existing Metro Line No. 1. There are plenty of pipeline around and the surrounding environment is complex. The strata are mainly about clay rocks and conglometrates and are stable. In the original design scheme, the secant pile is used for water stop and the support of foundation pit floor is replaced. The original design scheme is optimized so as to shorten the construction period and reduce the construction cost. In the optimized design scheme, the secant pile and the support replacement are removed, the position of the forth support is adjusted and the waterproof material is changed. The excavation situations of the deep foundation pit before and after optimization are analyzed by Lizheng software. The construction process of the deep foundation pit is monitored after optimization, and the measured data are analyzed. Some suggestions are shown as follows: 1) The support of deep foundation pit should not be replaced. 2) The design of the foundation pit should be dynamically adjusted and referenced from calculation results of simulation software. 3) Monitoring is very important during deep foundation pit construction.

Key words: metro deep foundation pit, optimization of support structure, construction monitoring