Geotechnical Monitoring & Instrumentation | G3 SoilWorks

When it comes to construction, the ground can be unpredictable. As such, even with a high-quality geotechnical design, it is essential to monitor the progress of a construction project as well as the performance of an excavation, fill pad or slope. This is where geotechnical monitoring comes in.

What is geotechnical monitoring?

Geotechnical monitoring refers to the ongoing evaluation of ground performance against the project’s design assumptions, and it allows the engineer to make informed changes to the construction’s design to ensure its stability.

It’s often required by statutory authorities on large projects that are close to built-up areas or sensitive structures. This type of monitoring tracks ground movements, water pressure, vibrations and structural movements. More specifically:

• The deformation of soil, structures and rock
• Stressors that impact on structures like shafts, tunnels, embankments and walls
• The pressure, flow and quantity of ground and surface water

Common geotechnical instrumentation

There are a number of monitoring instruments and sensors used by engineers to measure and analyse data. For example:

• Inclinometers: Used for measuring angles of slopes in relation to gravity’s direction.
• Piezometers: Used to measure water pressure, they are often positioned in boreholes to monitor groundwater.
• Settlement plates or gauges: Used for monitoring settlements during the lifespan of a project.
• Tilt meters and crack monitors: Similar to inclinometers, a tilt meter measures sensitive structures to check for very small changes from the vertical level.
• Extensometers: Most often used for measuring vertical displacements in the ground, there are video and laser extensometers available.
• Contractometers: Essentially an extensometer that works in reverse, it measures compression and convergence (loading and settling).
• Instrumented cable bolts: These are used to measure displacement, strain, and load by engineers, technicians and consultants.
• Ground movement monitors: As the name suggests, it measures general movement including ground shift and rock fall.
• Sloughmeters: Used in areas where caving or ‘sloughing’ of the ground is expected.
• Thermistors: Provide reliable and accurate temperature measurements in harsher environments.
• Hydrological sensors: These sensors measure aspects relating to water, e.g. pressure, depth and moisture percentage.

An engineer may choose to use a number of these instruments in order to collect raw data. This data is then analyzed and interpreted to give the engineers an overall understanding of the mechanics and stresses affecting the construction. Once they have this information, they will decide how to best manage the construction to ensure the highest levels of productivity and safety.

Contact G3Soilworks

If you’re looking to improve the productivity and profitability of your project in California, contact G3Soilworks today. As consultants, we can help support you with our geotechnical and geological expertise.