Quantitative Evaluation of Ground Movements Caused by Grouting during Shield Tunnelling in Clay

Grouting has been deemed as one of the most effective measures for mitigation of ground movements during tunnel construction in soft soil. Notwithstanding that, a reliable measure to quantitatively evaluate the grouting-induced ground movements during shield tunnelling in soft soil has not yet been developed. This paper presents a simple method capable of quantitatively estimating the ground movements associated with grouting for tunnel-boring operations where the grouting parameters and soil properties are taken into consideration. The grouting process is simplified as the expansion of a cylindrical cavity with a uniform radial stress applied at soil-grout interface in a half plane, and the analytical solution proposed by Verruijt is introduced for determining the ground movements by the expansion of the cylindrical cavity. The proposed method is verified with a case history undertaken in London Clay. The results obtained suggest that this procedure would be helpful in managing the grouting parameters adopted in upcoming soft ground tunnelling project and mitigating the environmental impacts on nearby properties.