Pile Axial Force / Strain
Distributed strain along full pile length with ±1 με
Monitoring solution
Depth-wise sensing for foundations and deep excavations.
Distributed strain, axial force, and temperature sensing for pile foundations, diaphragm walls, tunnels, and deep excavation projects using UW-FBG technology.
The engineering question
What must be observed before failure becomes visible?
Deep excavations, pile foundations, and underground structures involve complex soil-structure interaction that varies continuously with depth. Traditional vibrating wire strain gauges and inclinometers provide readings at discrete depths, missing critical stress concentrations that can lead to foundation failure, excessive settlement, or damage to adjacent structures.
Urban metro stations, high-rise basements, and underground utility tunnels are often built adjacent to existing buildings and infrastructure. The safety of these adjacent structures depends on real-time knowledge of ground movement and structural response at every depth level — information that only distributed sensing can provide at the required resolution.
Monitoring boundary
Define the quantity, coverage and required response first.
UW-FBG embedded strain sensing cable
Diaphragm Wall Deformation
Continuous wall deflection profile during excavation
Ground Settlement
Sub-mm settlement tracking around excavation
Rebar Stress
Steel stress monitoring in reinforced concrete elements
Temperature
Mass concrete temperature during curing
Adjacent Structure Impact
Real-time displacement of nearby buildings
Sensing chain
Treat sensing, interrogation and interpretation as one system.
The underground monitoring system embeds UW-FBG sensing cables directly into pile reinforcement cages, diaphragm wall steel cages, and tunnel linings during construction. Each cable provides continuous strain and temperature profiles along the entire structural element. Surface settlement arrays are deployed around the excavation perimeter. An RS-HFBGA interrogator collects data from all fiber channels, and the Ray-Sensor platform processes and displays real-time deformation profiles, construction phase alerts, and automated reports for site engineers.
Field placement
Translate the monitoring question into a placement plan.
- 01
UW-FBG strain cables tied to pile reinforcement cages before concreting
- 02
Diaphragm wall strain cables paired with flex inclinometer for full deformation profile
- 03
Surface settlement arrays using FBG settlement cells around excavation perimeter
- 04
FBG rebar strain gauges on key structural reinforcement members
- 05
Temperature monitoring arrays in mass concrete pours for thermal control
- 06
RS-HFBGA interrogator positioned on-site with real-time data display
- 07
Automated alerts for threshold exceedance (wall deflection, pile strain, settlement)
Engineering record
What continuous measurements make visible.
- Continuous depth-wise profiles — no gaps between discrete sensor levels
- Real-time safety monitoring during critical construction phases
- Early detection of abnormal soil-structure interaction before visible damage
- Optimized foundation design validated by field data from distributed sensors
- Automated reporting for regulatory compliance and construction records
- Protection of adjacent structures with real-time displacement alerts
Field evidence
Related monitoring contexts.
Define the monitoring boundary
Start with the asset, failure mode and required coverage.
These inputs determine the sensing layout more reliably than choosing an instrument first.