Assessment of Rock Fracture Jacking During Grouting: Evaluation of an Analytical Solution Through Cases from Scandinavian Tunneling Projects-Video

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The presentation proposes an analytical method for controlling rock jacking during grouting. It combines real-time grout-spread estimates with deformation-limiting curves (DLCs), which relate injection pressure, grout spread, and fracture dilation. Used as stop criteria, DLCs can help limit dilation while improving penetrability. Two Haga Tunnel case studies illustrate the approach: modest, controlled dilation accelerated grouting with little extra grout, while excessive pressure enlarged fractures substantially and increased grout consumption by about 30%. The findings suggest that controlled elastic jacking can be beneficial, but uncontrolled dilation may waste grout and reopen previously grouted sections.

Keywords

rock jacking

grouting control

deformation-limiting curves

grout spread estimation

Haga Tunnel case studies