In view of the grouting reinforcement requirements of
argillaceous soft rock tunnel and the performance disadvantages of common
single grouting materials, the nanosilica sol and aluminate cement is
considered as the main agent, and a type of composite grouting material with
silica sol/water/aluminate cement (100 mL/100 mL/120 g) is prepared. The
preliminary study demonstrates that a simple combination of nanocolloidal
silica-aluminate cement will lead to a low stone rate and cracks in the
stone bodies. As a result, two admixtures of sodium silicate and Portland
cement are chosen to study the influence of their dosage on the stone rate, 3day compressive strength, and gel time. On the premise that the
stone rate reaches 100% and the 3day compressive
strength and gel time are considered the main and auxiliary factors,
respectively, the sodium silicate exhibits a better performance; its dosage is
1% of aluminate cement. Further, 1% sodium silicate is used as the conventional
ratio for the subsequent tests. To solve the cracking problem, four admixtures
of silica fume, magnesium oxide, calcium oxide, and redispersible latex powder
are chosen to study the influence of their dosage on cracking, 3day compressive strength, and gel time. On the premise that cracks
can be completely treated and the 3day compressive
strength and gel time are considered as reference bases, the magnesium oxide
has the best performance in cracking prevention, and the recommended dosage is
0.6% of aluminate cement. Finally, based on the theory of interface transition
zone, the reinforcement effect of grouting material on the mudstone of the
Xianglushan tunnel in Central Yunnan is evaluated. The results indicate that
the average width of the magmatic interface transition zone is only 88.6 μm, the microhardness slightly decreases, and the interface between
rock and grout is firm.
LIU Ningkai
,
PAN Dongjiang
,
WEN Shiyu
,
LIU Haining
,
ZHOU Jianjun
,
LI Zhiguo
. Design and Performance Optimization of a NanoColloidal
Silica Aluminate Cement Composite Grouting
Material for Argillaceous Soft Rock Tunnel[J]. Tunnel Construction, 2022
, 42(2)
: 303
-312
.
DOI: 10.3973/j.issn.2096-4498.2022.02.016
