GEO-Instruments monitors support of excavation systems to validate design decisions and provide early detection of any problems
Support of Excavation Systems
Support of excavation (SOE) systems are designed to provide lateral support for the soil around the excavation, maintain a safe work area, and minimize impact to adjacent structures.
Common types of SOE systems include:
- steel sheet piling
- soldier piles and lagging
- jet or chemical grouting
- secant or tangent piles
- soil nail walls
- anchors and bracing
Design Decisions
The design of a support of excavation system involves a myriad of parameters including soil type and properties, lateral loads from adjacent structures, ground water pressure and water inflows, the width and depth of the excavation, and many more.
The performance of the support system is affected by complex interactions of the parameters above as well as less predictable variables such as weather conditions, repositioning of heavy construction equipment and stockpiled materials, and vibrations from traffic, railways, and nearby construction sites.
Validation & Early Warning
Design decisions are validated when the predicted behavior of the support system matches the actual behavior. Instrumentation can provide early warning when measurements trend away from predicted behavior.
Geotechnical instrumention can monitor the parameters below:
- Deflection of the retaining structure
- Displacements of soil behind the retaining structure
- Displacement of adjacent structures and utilities
- Loads on anchors and bracing
- Pore-water pressures
- Vibration levels
Monitoring Support of Excavation
Instruments used to monitor SOE systems:
AMTS to monitor lateral movement of walls. Prisms can be clamped magnetically to soldier piles and sheet piles. Prisms can also be installed on soil-nail walls.
Tiltmeters placed on soldier piles and sheet piles to monitor deflection.
Shape Arrays to monitor lateral movement in or behind earth retention structures.
Piezometers installed outside the excavation to monitor changes in pore-water pressure.
Strain gauges to monitor changes in strain on struts and braces.
Load cells to monitor changes in loads on tieback anchors.
Weather stations to monitor rainfall and temperatures.
Monitoring Adjacent Structures
Instruments used to monitor adjacent structures:
AMTS to monitor any movement of buildings adjacent to the excavation. Prisms are installed on building facades.
Tiltmeters placed on walls and structural elements to monitor rotation (leaning or tilting).
Crackmeters to monitor existing cracks that may worsen if settlement occurs.
Hydrostatic Level Cells to monitor differential settlements. HLCs are especially effective on masonry structures.
Vibration Monitors to monitor for excessive vibrations from the excavation activities.
Also see Pre-Construction Surveys
GeoCloud Automation operates 24/7 to deliver measurements from the project work site to secure project web sites. GeoCloud automation features wireless data acquisition, web-based data management, and website access to data.
Wireless data acquisition systems forward measurements to GeoCloud servers for processing. Dedicated GeoCloud websites provide access to alerts, graphs, and reports.