Emergency works and culvert design – Thorrington Culvert


In March 2018, a section of railway embankment on the Colchester and Clacton line was subject to failure due to partial collapse of a culvert. We were commissioned to advise on temporary works to stabilise the track and subsequently investigate options to either remediate the existing culvert or construct a new culvert adjacent to the existing structure.

The main site constraints included the requirement to keep the busy commuter line open, difficult access and the presence of protected species.


We advised the client on the requirements of temporary works to support the track and completed slope stability analysis to verify the emergency works. A comprehensive options appraisal for the site recommended decommissioning the existing culvert and forming a new culvert using microtunnelling.

We produced an interpretative ground investigation report, completed geotechnical and hydraulic design of the proposed culvert and advised on soil nailing and compensation grouting works to stabilise the embankment above the existing culvert. A 3D CAD ground model was developed to determine the optimal location for the soil nails and to project the proposed culvert through the strata identified during the ground investigation. Settlement calculations were completed using industry recognised software to estimate potential settlement during construction and early stage mitigation options. We also completed a preliminary ecological appraisal and provided support in gaining permissions for the work from the local authority.

The failed culvert has been stabilised and the construction of the new culvert is planned for.


We worked effectively with the client to demonstrate that emergency works to stabilise the embankment were sufficient to enable trains to run while design proceeded on a permanent solution. We successfully completed optioneering and design works on very short deadlines and progressed the design.

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Email James Howard to find out more about this project and the work our Geotechnical team do.

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