Projects
Monitoring of Tunnel Entrances – River Noord, Alblasserdam, Netherlands
Alblasserdam, Netherlands
Project duration: July 2024 until December 2028
A multi-year monitoring programme was established for the tunnel under the River Noord in Alblasserdam, including continuous monitoring of both tunnel entrances. Measurements started one year before renovation works to capture the tunnel’s natural behavior, such as deformation caused by temperature, groundwater levels and dynamic loads. These reference datasets support safe and well-controlled renovation planning.
Insight into both natural and project-related tunnel movements, providing objective reference data that mitigates liability risks for all stakeholders.
Project Purpose
The objective is to accurately record all longitudinal changes in tunnel length and to identify the influence of external factors. The collected data enables early detection of structural stress and ensures that renovation activities do not trigger abnormal or potentially hazardous displacements.
Implemented Solution
Four Locator One units continuously monitor both tunnel entrances with a high measurement frequency. The sensors record daily positional variations to capture temperature-related length changes. Movements of several centimeters and indications of stress, such as debris in expansion joints, were detected. Dual reference stations and continuous logging allow reliable detection of trends and deviations from natural movement patterns.