Indoor modeling experiments are conducted to
investigate the influence of quasirectangular shield tunneling
on the confining pressure and deformation of adjacent existing tunnels in sandy
soils. In this study, ground loss during 〖HJ3.8mm〗the construction as well as the relative positions of the new and
existing tunnels are investigated. Different construction conditions, including
overlapping underpass, pinch underpass, and orthogonal underpass with varying
tunnel spacings are assessed. Results indicate that: first, among various
construction conditions, the new quasirectangular
shield tunnel has the most significant impact on the existing tunnel when it
passes through in a constrained manner. Under this condition, quasirectangular shield tunneling beneath the existing tunnel leads to a
sudden and notably remarkable change in the confining pressure at the bottom of
the tunnel′s arch. Then, the spacing between tunnels
remarkably affects the confining pressure, the strain at the arch bottom of the
existing tunnel, and the displacement at the crown of the existing tunnel
during the new quasirectangular shield tunneling.
Therefore, a sufficiently safe distance between the new and existing tunnels
must be maintained. Finally, the deformation of the existing tunnel crown is
sharply increased in a certain stage during the new quasirectangular shield tunneling underneath. In actual engineering,
considerable attention must be provided to control the deformation rate in this
stage.
ZHAO Deqianlin
,
WEI Gang
,
LIANG Luju
,
JIANG Haibo
,
XIANG Pengfei
,
MU Zhiyuan
. Experimental Study on Responses of Existing Tunnels to
Adjacent QuasiRectangular Shield Tunneling
in Sandy Soil[J]. Tunnel Construction, 2024
, 44(5)
: 1000
-1011
.
DOI: 10.3973/j.issn.2096-4498.2024.05.009
