Hydrostatic Levelling Cell (HLC) systems precisely measure vertical structural movement in real-time using a network of connected sensors.

Technology image hydrostatic levelling cells

Common uses

Ground settlement monitoring for excavation, demolition or tunnelling
Structural monitoring of tunnels, buildings and basements
Uplift monitoring during compensation grouting
Monitoring of track beds and sensitive assets.


HLCs are high accuracy system designed to measure vertical movement and can accurately measure heave or settlement within a 500mm range.

System components include a reservoir, Hydrostatic Levelling Cells, tubing, cabling, deaired liquid, and a datalogger/PC.
The cells are connected into a circuit using liquid and air tubing, then filled with fluid via the reservoir.
One cell is assigned as the reference cell and is placed outside the zone of influence. 

When a structure experiences settlement or heave, the cells record a change in pressure. 
Pressure readings from monitoring cells are compared to the reference cell and a baseline to accurately calculate movement across the system.
The use of a reservoir and reference cell in this way eliminates factors that effect the whole system, such as changes in fluid level from evaporation.

HLCs are fully integrated with our web monitoring interface, Quickview. Data is streamed online within minutes from data acquisition, so that construction can be directly guided by the actual ground movement. 

The systems are supported by purpose-built software that provides easy-to-use graphical visualisation, automated reporting, and a robust alarm system that can send instant alerts if any set threshold is breached.

HLCs can be particularly useful in situations where conventional survey techniques are not feasible (e.g. basement monitoring).

GEO-Instruments have unparalleled experience with HLC systems, having installed several thousand sensors globally. Our largest system to date, used to control settlement and heave on a London based project, required 1700 cells.


  • High accuracy: The system is extremely accurate, with a resolution of 0.024mm.
  • Integrated data: Structures can be monitored on all sides with one system. It is possible to visually map vertical movement under an entire building with accompanying QuickView software.
  • Real time: Data is available online within minutes from data acquisition. Construction can be actively guided by observed movement.
  • Low maintenance: Cells do not need regular access and can reliably work for several years without intervention.

Video featuring HLCs