Precise monitoring surveys can be used to monitor movement on a building or structure that shows previous signs of movement or may be susceptible to movement or damage in the future.
The main causes of instability are mining activities, ground movement, nearby construction works and subsidence.
Landform Surveys has recently been working with Northumbrian Water on a monitoring survey of domestic properties in County Durham.
Northumbrian Water came to us in advance of an excavation project they were planning near a group of residential houses. They wanted advice on how to monitor properties for movement, as they were planning on installing a water main to the rear of a group of houses. There were concerns around whether the excavation activities would have an effect on nearby properties.
Before any works took place, we established secure, stable monitoring pins on the corners of each of the property within the affected area. We then took a series of multiple baseline readings which would be used to compare future readings and verify any movement.
The points were then monitored on a weekly basis, to compile a series of readings over the course of the excavation. The same baseline was used for each property and any movement was immediately flagged up with the client while their work was being done. Our surveys were accurate to 0.1mm, which meant that even if the movement was very small, it was still reported on.
Throughout the monitoring, there was no movement to report, which was the ideal outcome for both Northumbrian Water and the homeowners. By commissioning a monitoring survey, Northumbrian Water protected themselves against any subsequent claims from homeowners. Homeowners also benefited from knowing that their properties and safety was ensured and that no further measures would need to be taken to secure their homes.
This was another successful survey where the data collected helped to create a satisfactory solution for all those involved in the project.