Two centrifuge model tests with different vertical clearances were carried out to investigate the new shield tunneling on an existing overlying large-diameter tunnel. The difference of the two centrifuge model tests lies in different vertical clearance between the two tunnels. Two construction steps of a new shield tunnel were simulated in the test. The vertical displacement and the longitudinal strain of the existing tunnel, as well as the pore water pressure at its invert and spring line, were measured. Results show that the vertical displacement and the longitudinal stress and the longitudinal differential settlement of the existing tunnel increase along with the vertical clearance of the two tunnel. The vertical displacement and the longitudinal stress of the existing tunnel and the pore water pressure increase because of the excavation while decrease as a result of grouting. The longitudinal differential settlement of the existing tunnel increases with the proceeding of the construction steps of a new shield tunnel.

LOKASI: Ruang Koleksi Umum
Rak: 2