Centrifuge modeling of effect of excavation on adjacent underpasses of deep foundation pits with shorings

First, a new automatic oil-controlling system for real-time modeling of the excavation of the deep foundation pit with shorings is presented, which can be installed in the 150-ton multi-function centrifuge in the Centrifuge Laboratory of Tongji University, China. Based on the automatic system, the excavation of different layers of soils is simulated by discharging different volumes of special liquid, and the installation of the shorings on a retaining wall after excavating the above soils timely is simulated by locking the shoring of the system. Accordingly, the construction of a deep foundation pit with shorings can be modeled at high-speed flight operations of the centrifuge. Second, the centrifuge modeling of the effect on the adjacent 3 m underpass induced by excavating 32.7 m-deep Yanggao air well of Metro line 9 of Shanghai is introduced. The comparison between the observed data and the modeling data shows that the automatic excavating system of the centrifuge can effectively model a complete excavation with shorings. Finally, the results of the settlement of the underpass by different mixture-pile barrier walls for improving soil between the excavation and the underpass are compared. It is concluded that the barrier walls can effectively decrease the settlement of the adjacent underpass. The barrier wall should be deeper than the excavation depth in order to make an effective barrier, and the length limit of the barrier walls should be the half depth of excavation beyond the excavation zone.