Abstract: Theoretical solution based on Newton fluid assumption was used to estimate the effectiveness of grouting in fractured rock encountered at Jiaozhou Bay Tunnel.  The solution suggests 1) predetermined grouting radius can be achieved with a design pressure of 3 to 4 MPa, a grouting hole radius of 5 cm, and a grouting duration of 1800 to 3600 seconds; 2) the effective radius of grout zone increases with time; 3) the effective radius of grout zone increases with grout pressure; 4) the effective radius of grout zone increases with the aperture of rock fractures.

Key words: Underwater Tunneling, Fractured Rock, Radius of Grout Zone, Newton Fluid