To solve the problem of slurry being difficult to
diffuse during grouting construction in silty fine sand stratum, a case study
is conducted on the grouting project of the mining excavation section of the
connecting line between Zijingshan and Dongda Street stations of Zhengzhou
metro line 2, and the composite grouting scheme of sodium metaaluminate
modified sodium silicate slurry and ultrafine cement single slurry is
tested and applied. The practical results show the following: (1) The diffusion
radius of sodium metaaluminate modified sodium silicate slurry is more than 1
m, the injectability is good, and the total amount of grouting reaches 92% of
the design. (2) The sodium aluminatemodified sodium
silicate slurry is injected first. Then, it solidifies and forms a chemical
slurry vein. Furthermore, the ultrafine cement slurry
is injected into adjacent holes to split and diffuse along the chemical slurry
vein to form a composite slurry vein, to fully improve the strength of the
surrounding rocks in the reinforcement area. In the whole process of grouting
and excavation, the cumulative deformation of surrounding buildings
(structures) and strata is less than 4 mm. Recently, several grouting
construction cases in silty fine sand stratum are summarized and analyzed.
After comparison with phosphoric and sulfuric acids modified sodium silicate
slurry, it is pointed out that sodium metaaluminate modified sodium silicate
slurry has the advantages of good safety, short setting time, and large
diffusion radius. The sodium metaaluminate modified sodium silicate slurry can
be obtained from various sources at a greatly reduced cost, thereby reaching
good economic and applicable benefits.
WANG Yue
,
XU Qipeng
,
MA Zhaolin
. Practice and Optimization of Grouting Scheme for
Expansion Excavation of Tunnel in Silty Fine Sand Stratum of
Zhengzhou Metro[J]. Tunnel Construction, 2021
, 41(12)
: 2140
-2149
.
DOI: 10.3973/j.issn.2096-4498.2021.12.015
