To investigate the soil fluidity mechanism of a silty
fine sand stratum that is improved by bentonite slurry for earth pressure
balance shield, a jumping table and crossplate shear tester are used to
test the fluidity and shear parameters of the improved soil. Furthermore, the
shear stressstrain relationship and rheological model
are analyzed. The results are as follows: first, in slurry with bentonite to
water ratio of 1∶4 is mixed by a mass ratio of 7% ~
13%; similarly, that with bentonite to water ratio of 1∶6 is mixed by a mass ratio of 7% to improve the fluidity of the
silty fine sand. Second, adding an equal amount of free water does not improve
the fluidity of silty fine sand. Third, as the amount of the slurry increases,
the ratio of bentonite to water decreases; thereby, leading to an increase in
the fluidity of the improved soil. Thus, fluidity is negatively related to
shear stress. Fourth, the improved silty fine sand follows the Bingham model,
and the decrease in plastic viscosity and yield stress is the primary cause of
its increased fluidity.
LI Hongfei
.
Fluidity Mechanism Analysis of Bentonite Slurry
Improved Soil
for Earth Pressure Shield in Silty Fine Sand Layer
[J]. Tunnel Construction, 2022
, 42(2)
: 253
-259
.
DOI: 10.3973/j.issn.2096-4498.2022.02.010
