Post on 20-Apr-2020
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HYDRA-G Case Study
Building Monitoring
during TBM Excavations
The main line subway of an
European city is going to be
extended along the south
direction.
In order to create the new tunnel,
a TBM was used for drilling
activities.
The HYDRA-G radar installation
was carried out to monitor civil
structure and building
movements next to the new
metro line site, and during the
TBM transition period.
The HYDRA-G position is
highlighted by the yellow circle in
the image.
N
W E
S
AREA FRAMING
HYDRA-G Case StudyScope of the Project
HYDRA-G
Position
HYDRA-G
Line of Sight - LOS
HYDRA-G Case StudyArea Framing – HYDRA-G Positioning
The HYDRA-G radar system was placed in a stable area,
on a cement block of 1 m3.
The blue square in the image below indicates the
buildings that were selected for the monitoring
activities.
HYDRA-G Case StudyHYDRA-G Installation on September 22, 2017
HYDRA-G Case StudyFirst Step of the Campaign: 3D Point Cloud Creation with the SurfScan Software
Radar Pixel Creation: 22/09/2017
Installation and
beginning of the
monitoring
Selected radar pixels for real time
displacement visualization Creation of Time Series for Real time
Displacement: 22/09/2017
HYDRA-G Case StudySecond Step of the Campaign: Radar Monitoring Session
Phase 1
Wed 27 h 10:00 - Wed 27
h 18:00: TBM is
approaching the area.
Phase 3
Thursday 28 h 8:00 – Friday 29 h 15:00:
TBM drilling under the selected area. Main movements
(up to 5 mm) are shown here.
Phase 2
Wed 27 h 18:00 – Thu 28 h
08:00: Stop drilling for
technical reasons.
Building A
Phase 4
Friday 29 h 15:00 -
Saturday 30 h 09:00:
Stabilization of the selected
radar pixels. TBM finished
drilling between Friday and
Saturday night.
Building B
Building C
Building A
Building B
Building C
Phase 1LOS
displacement
up to 2 mm
Phase 2No displacement
due to TBM stop
Phase 4:Movement
stabilization
Phase 3 LOS displacement up to 6 mm
Monitoring – Time Series
Building A
Building B
Building C
Building ABuilding B Building C
The HYDRA-G radar system was able to
monitor in real time building and civil
structure movements above the subway
tunnel construction.
A detailed analysis of the data highlighted
the different movements between the
surveyed buildings.
Building A: an average of - 6 mm
displacement respect lo LOS
Building B: an average of ± 2 mm respect to
LOS
Building C: an average of +2 mm respect to
LOS
HYDRA-G Case StudyConclusion