Project Overview

The client had a problem with a retaining wall on their property which exhibited a slight bulge. The objective of the survey was to identify any movement over time to assess the structural stability and inform any necessary remedial action. The monitoring project needed to address several specific challenges to ensure the data was reliable:

• High-Accuracy Targets: Targets needed to be installed on the wall that could be measured to a high accuracy, in the range of a millimeter.
• Long-Term Monitoring: The survey needed to establish a precise baseline to allow for ongoing, periodic monitoring (e.g., every month) to identify any problematic areas or movement trends.
• Stable Reference Points: A strong control network was required, with control points installed in stable locations, away from the wall, to act as a consistent reference system for all subsequent measurements.
• Obstruction Management: The survey location, a parking area, presented a challenge, as parked cars could obstruct the line of sight to the targets.

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Project Outcome

The initial monitoring survey was successfully completed across both the upper and lower levels.

• Data Captured: All required observations were taken with a resulting accuracy expected to be around one millimeter.
• Movement Identified: The majority of the movement was observed in the area of the wall that exhibited the visible bulge.
• Processing: The data was downloaded from the TSC5 loggers and will be processed through Starnet software to convert the measurements into 3D coordinates.
• Reporting: A final comparison and analysis of the coordinates will be performed using a conventional spreadsheet to produce the final report for the client detailing the wall’s current movement and structural status.

Future Value Includes:

• Long-Term Record: The established control network and baseline data can be re-used for future monitoring visits, creating a long-term digital record of the wall’s performance.
• Informed Decisions: The accurate measurement of movement will help the client and their engineers to:
  • Support the design and planning of any necessary remediation or structural changes.
  • Reduce the risk of errors during construction by working from precise measurements.