Abstract: The free stationing total station survey method is usually used in the monitoring of horizontal displacement in a deep excavation. An improved free stationing method is proposed in this paper. This improved method can effectively resolve the problem of setting a stable station or stable reference point using the conventional free total station method. In addition, this method can be operated without measuring the distance between the station and the reference point. Therefore, the method can be easily operated and all the target points along the same side of the excavation can be monitored in just one stationing setup. The theoretical analysis and survey error estimation along with the experimental results demonstrate that proposed method is effective and reliable for the deep excavation deformation monitoring.

Key words: deep excavation monitoring, horizontal displacement, free stationing