To investigate the cracking mechanism of concrete on
the top of diaphragm walls, a case study is conducted on a largediameter
shield tunnel section of the Nanjing metro. By field investigation and extended
finite element analysis, the crack mode, distribution characteristics, and
cracking process of the concrete on the top of the diaphragm wall in the tunnel
are studied. The results reveal the following: (1) There are 96 cracks on the
top of the diaphragm wall, and the crack modes are types Ⅰ, Ⅱ, Ⅲ, Y, and Z,
among which types Y and Z cracks are subtypes of type Ⅰ cracks. (2) The cracks start at the opposite side of the horizontal
differential displacement of the flue plate; the development curves of the
length and end width of types Ⅰ and Ⅱ cracks show a threestage characteristic;
the end width and length of the cracks are nonlinearly related; 250 and 225 mm
are the critical crack lengths with the rapid growth of the end width of types Ⅰ and Ⅱ cracks, respectively. (3) In type Ⅱ cracks, the propagation curves of two cracks under the same working
condition are consistent, and the space of plate joints significantly
influences the length and slope of each stage of the curve; the first crack
propagation process in type Ⅲ cracks is consistent with
that in types Ⅰ and Ⅱ cracks,
and the propagation of the other two cracks have obvious brittle
characteristics.
DONG Fei
,
HUANG Jun
,
LI Ao
,
GAO Caichi
,
CHEN Ningwei
. Crack Mode and Propagation Mechanism of Diaphragm Wall
Top in LargeDiameter Shield Tunnel[J]. Tunnel Construction, 2023
, 43(1)
: 82
-91
.
DOI: 10.3973/j.issn.2096-4498.2023.01.009
