To investigate the
functional relationship between different seepage states of tunnels and the
water pressure behind the lining, as well as the bearing safety of cracked and
seeping lining structures, a set of constant-pressure
and constant-flow water supply equipment suitable for
large-scale model tests is developed using stabilized
air pressure method. This equipment enables the stable generation of local
water pressure under a large flow rate and the control of water head height at
the decimeter level. Furthermore, a large-scale model
test with a scale of 1∶50 is conducted indoors to
examine and map out the magnitude of water pressure behind the lining based on
directly measurable existing apparent phenomenon indicators such as seepage
volume and crack opening degree, thereby assessing the bearing safety of
cracked and seeping lining structures. The results indicate that: (1) Affected
by the roughness and tortuosity of cracks, in actual engineering, the seepage
volume of cracked and seeping linings varies non-linearly
with the water pressure behind the lining. The functional relationship between
the seepage volume and the water head height is y=19.69e(x/2.45) -18.06. (2) Under
the combined action of water pressure and soil pressure, the axial force at the
seepage part of the cracked lining significantly decreases; the direction of
the bending moment changes, demonstrating a "hinge effect", and the
safety factor drops sharply in an exponential form with an increase in seepage
volume.
JIANG Xinghong
,
LI Ke
,
XIAO Shilai
,
LIU Min
. Development and Application
of Similarity Test Equipment for Load-Bearing Mechanical Characteristics of Tunnel Structures Under
Hydraulic Pressure[J]. Tunnel Construction, 2024
, 44(S2)
: 115
-122
.
DOI: 10.3973/j.issn.2096-4498.2024.S2.012
