Soletanche Bachy - Build on Us

Compensation grouting

Tunnel driving inevitably causes surface settlement, following the form of a Gaussian curve, that is a potential source of substantial damage. Compensation grouting is an active technique to offset soil decompression arising from settlement, by injecting precise quantities of grout between the tunnel and the structures exposed to the danger.

The key factors are as follows:
• Precise amounts of grout injected,
• Perfect synchronisation of grouting and settlements: the grouting should anticipate the settlement.
• Precise, real-time monitoring of the grouting and soil and structure deformations.

This technique fits in perfectly with the Observational Method: compensation grouting can comprise the main part of the contingency plan to protect adjoining structures when the tunnel is being built.