2012, the government of the city of Shanghai decided that the subway tunnels in Shanghai must be monitored through automatic measurements.

Due to its high sensitivity and measurement accuracy, the Glötzl Hose Gauge Measurement System GHD 3 was successfully retrofitted into six subway lines for this purpose. Previously, all measurements were carried out manually using leveling or total stations. With the hydrostatic measurement system GHD 3 from GLÖTZL, height profiles are measured at defined time intervals, from which settlements or heave can be determined with an average accuracy of about 0.02 mm. At the same time, manual leveling measurements are also conducted to ensure the plausibility by comparing both measurements. Figure 1 shows the result of the comparison measurements. The curves of both measurements are nearly identical within the expected measurement uncertainties. The hose gauge system has significantly exceeded the allowable limit of -10 mm at measurement stations F20A-7 to -9, providing a timely warning.

Project: Tunnel Shanghai
Planning: 2013 – 2015
Special features: Monitoring length > 20 km
Other: 6 sub-projects for 6 lines
GLÖTZL Measurement Technology: Hose Gauge System GHD 3
729 hose gauge sensors and more than 80 reference stations