A case study of
the shafttype underground parking garage of Harbin Provincial Party Committee
Square is conducted to examine the deformation characteristics of shafttype foundation pit excavation and the influence of pitinpit excavation on the overall stability
of the foundation pit. First, the deformation monitoring scheme and results of
the shafttype foundation pit are reviewed. Second, the
finite element software MIDAS/GTS is used to create a finite element
calculation model for shafttype foundation pit, and
the accuracy of the calculation model is verified by comparing it with the
monitoring results. On this basis, the evolution law of the annular arch effect
in the construction process of shafttype foundation
pit is discussed, and influencing factors such as foundation pit diameter and
supporting pile diameter are analyzed. Finally, the secondary excavation in the
shaft pit is analyzed using the strength reduction method, and the influence of
the platform width and pit depth on the pit stability is studied. The results
are as follows: (1) The maximum measured horizontal displacement of the pile is
3.5 mm, and the maximum settlement is 11.6 mm. (2) The circular arch effect of
the circular foundation pit can be expressed using the soil′s medium principal stress vector diagram. The soil range of the
circular arch effect gradually expands as the excavation depth of the
foundation pit is gradually increased. (3) When the excavation depth ratio of
the inner and outer pits is 0.44, the influence of inner pit excavation on
foundation pit stability should be considered.
LI Hongjun
,
LENG Yuan
,
ZHANG Shilong
,
LIU Changyong
. Deformation Characteristics and Stability of ShaftType
Foundation Pit Excavation[J]. Tunnel Construction, 2022
, 42(8)
: 1395
-1403
.
DOI: 10.3973/j.issn.2096-4498.2022.08.008
