Underground, Foundation & Deep Excavation Monitoring
Distributed strain, axial force, and temperature sensing for pile foundations, diaphragm walls, tunnels, and deep excavation projects using UW-FBG technology.
Industry Challenge
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 Objectives
Target measurement parameters, performance specifications, and sensing methods for underground, foundation monitoring.
| Parameter | Target Specification | Method |
|---|---|---|
| Pile Axial Force / Strain | Distributed strain along full pile length with ±1 με | UW-FBG embedded strain sensing cable |
| Diaphragm Wall Deformation | Continuous wall deflection profile during excavation | UW-FBG inclinometer + strain cable |
| Ground Settlement | Sub-mm settlement tracking around excavation | UW-FBG settlement monitoring array |
| Rebar Stress | Steel stress monitoring in reinforced concrete elements | FBG rebar strain gauges |
| Temperature | Mass concrete temperature during curing | UW-FBG temperature sensing array |
| Adjacent Structure Impact | Real-time displacement of nearby buildings | FBG tilt/ displacement sensors |
System Architecture
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.
Typical Deployment
Field deployment steps for a complete underground, Foundation & Deep Excavation Monitoring system.
- UW-FBG strain cables tied to pile reinforcement cages before concreting
- Diaphragm wall strain cables paired with flex inclinometer for full deformation profile
- Surface settlement arrays using FBG settlement cells around excavation perimeter
- FBG rebar strain gauges on key structural reinforcement members
- Temperature monitoring arrays in mass concrete pours for thermal control
- RS-HFBGA interrogator positioned on-site with real-time data display
- Automated alerts for threshold exceedance (wall deflection, pile strain, settlement)
Customer Value
Key benefits delivered by Ray-Sensor's underground, Foundation & Deep Excavation Monitoring solution.
Related Application Cases
Real-world deployments demonstrating underground, Foundation & Deep Excavation Monitoring in action.
Need a Underground, Foundation & Deep Excavation Monitoring Solution?
Contact our engineering team for system design and pricing tailored to your infrastructure monitoring requirements.
Request a Proposal