Abstract:

A physical model of sand filling test for Honggu Immersed Tunnel in Nanchang is established. The results show that the radius of sand accretion disk can reach 7.5-8 m when sandwater ratio reach 1∶8-1∶12, cement clinker content reaches 6% and sand filling pressure reaches 0.1-0.15 MPa. A series of technologies, including sand filling amount monitoring, sand filling pressure monitoring, underwater detection, tunnel segment measuring, fullwavefield nondestructive detection method and impact imaging method, are adopted. Some conclusions are drawn as follows: 1) The pressure and stop time of the sand filling pump for intermediate sand filling holes can be decided when the sand diffusion radius reaches 7.5-8 m and the filling degree reaches 65%; and that for side sand filling holes can be decided when the sand diffusion reaches 7.5-8 m and the overflowed sand mixed together. 2) The tube settlement is brought under effective control after the sand filling of foundation of E1-E6 segment is finished by choosing rational sand filling equipment and qualified sand materials and analyzing problems and their countermeasures. 

Key words: Hongu Immersed Tunnel in Nanchang, foundation sand filling, model test, fullwavefield nondestructive detection, impact imaging method, sand accretion disk monitoring