To investigate the deterioration of metro tunnel
lining support structures in harsh environments, freezethaw
and salt solution erosion are selected to examine the durability of tunnel
lining support structures based on typical climatic conditions and corrosive environments
during the service of a metro tunnel in western China. An indoor sulfate freezethaw erosion test is designed considering the autumn and winter
temperatures in Lanzhou as well as the ion concentration of sulfate in
groundwater. The effect of different amounts of fly ash and basalt fiber on the
mass loss rate, dynamic elastic modulus, and compressive strength corrosion
resistance coefficient of lining support shotcrete under freezethaw and sulfate is then studied. Finally, the compressive strength
attenuation model considering the content of fly ash and basalt fiber is
established based on the test results. The findings are as follows: (1) The
optimum contents of fly ash and basalt fiber are 20% and 0.1% respectively. (2)
The freezethaw cycle causes the concrete mass loss
rate to increase first, then decrease, and finally increase; the mass loss rate
of lining support shotcrete decreases with an increase in fly ash and basalt
fiber content; when the contents of fly ash and basalt fiber reach 30% and
0.15%, respectively, the reducing effect on the concrete mass loss rate is no
longer in force. (3) The relative dynamic elastic modulus and compressive
strength corrosion resistance coefficient of shotcrete increase with the number
of freezethaw cycles, with a small loss at first and
then increases rapidly.
XI Hongbing
,
LI Baisheng
.
Deterioration Performance of Tunnel Lining Support
Shotcrete under SulfateFreezeThaw
Interaction
[J]. Tunnel Construction, 2022
, 42(7)
: 1219
-1226
.
DOI: 10.3973/j.issn.2096-4498.2022.07.010
