Abstract:
The performance of large-scale deep excavations in Suzhou, China is comprehensively examined based on a great deal of field data, concerining the excavation of Suzhou Modern Media Plaza (SMMP), 11 rectangular excavations (i.e., aspect ratio of length to width is around 1.01~2.68) constructed by the bottom-up method and supported by auger-cast-in-place piles, and at least 23 long and narrow metro station excavations supported by diaphragm walls in the same area reported in literatures. On the basis of the analysis of monitoring data, some major findings are obtained: (1) the average of the maximum lateral wall deflection,
δhm, is 0.08%
He for the rectangular excavations and 0.20%
He for the metro excavations, where
He is the excavation depth; (2) the depth
Hm, where
δhm occurs, falls between
Hm =
He-10 and
Hm =
He + 5 for the rectangular excavations and between
Hm =
He-7 and
Hm =
He + 8 for the metro excavations.
Hm of the excavation propped by steel-reinforced concrete struts is a little smaller than that propped by steel pipe struts; (3) the maximum ground surface settlement,
δvm, is around (0.01%~0.09%)
He for the rectangular excavation of SMMP supported by diaphragm walls and around (0.04%~0.27%)
He for the metro excavations. The ground settlement zone is about 4.5
He behind the retaining walls for the metro stations which is larger than that of the rectangular excavations; (4) the ratio of
δvm/
δhm is around 0.13~1.07 for the excavation of SMMP and around 0.22~1.65 for the metro excavations; (5) the vertical column movement,
δcu, is around (0.07%~0.26%)
He for the rectangular excavations and around (0.10%~0.23%)
He for the