Effects of grouting in reducing excessive tunnel lining deformation: Field experiment and numerical modelling using material point method

Excessive deformation of tunnel lining structures can be identified as a common problem in Eastern China soft ground. Grouting treatment is an effective and method to actively mitigate excessive cross-sectional rings soils. However, grouting operations would introduce localized heavy disturbance the surrounding ground around nozzles, causing large-deformational soil movement. The occurrence large movement makes it difficult use traditional finite element methodologies when comes modeling effects on structures. To cope with this challenge, paper proposes simulation framework based Material Point Method, which enables explicit injection process natural incorporation deformation. On other hand, field experimental study operational shield metro has been conducted. involved extensive monitoring scheme various geometrical arrangements operation, thus data from records enable comprehensive comparison numerical results. between numerically simulated results shows satisfactory agreement. A sensitivity analysis parameters then carried out. both experiment show that increase height volume grout, recovery effect horizontal convergence improved. limiting values these grout exist, beyond any further become less effective. relative positions tunnel, horizontally vertically, also sensitive effect.