A case study is conducted on a foundation pit in
Nantong, China, to investigate the mesomechanism of ground collapse
induced by the leaking of underground diaphragm wall in waterrich sandy strata. In addition, the evolution law of the ground
collapse is analyzed by computational fluid dynamicsdiscrete
element method and related countermeasures are discussed. The following results
are obtained: (1) The included angle between the boundary line of the
influenced zone and the horizontal line is approximately (45°+〖WT〗φ/2)〖WT５《TNR》〗 in the
case of an underground diaphragm wall. The value and growth rate of ground
collapse increment induced by the leakage are large and within〖WT〗 1HL (HL〖WT５《TNR》〗=leakage
depth) behind the underground diaphragm wall. (2) During the leak, the ground
cavity undergoes generation, expansion, and collapse stages and rapidly
collapses with ground settlement. (3) Active earth and water pressure near the
leaking point increases by 5.7 to 8.5 times compared to that observed in the
model with no leakage. This increase is large when leakage occurs at or above
the excavation surface. Underground diaphragm wall leaking may lead to
structural cracks, abrupt ground subsidence outside the pit, and the kicking
damage of the retaining wall.
CHAO Hui
,
TAN Yong
,
LIU Tianren
.
MesoMechanism of Ground Collapse Induced
by Leaking of Underground
Diaphragm Wall in WaterRich Sandy Strata
[J]. Tunnel Construction, 2023
, 43(7)
: 1180
-1189
.
DOI: 10.3973/j.issn.2096-4498.2023.07.011
