Slope Formation Analysis

As part of the Hong Kong Hospital Authority’s 10-year Hospital Development Plan, a new acute block is being constructed adjacent to an existing hospital. To facilitate as much space as possible for the new acute block, some of the existing slopes were to be excavated.

The clearance between the designed slopes and the external wall of the new block was limited to maximise space inside the building, so the accuracy of slope excavations was critical.

Mott MacDonald, the Structural Design Engineers on the project, engaged Dronesurvey Asia to carry out an aerial survey during excavation and site preparation works to ensure accuracy of the works.

By overlaying the 3D scan mesh onto the Revit BIM models, Mott MacDonald’s engineers could easily identify areas of the slopes which were outside of the tolerance needed, and required amending.

3D photogrammetry capture was done with a DJI Phantom 4 Pro, and processed in PiX4D. Geo-correction and ground control points were set and measured with an Emlid Reach RS2 GNSS receiver.