The regularity of tunneling data is the foundation of
stratigraphic perception and big data analysis during shield tunneling in
composite strata. A section of Fuzhou metro passes through 16 kinds of strata
such as muddy soil, clay, broken pebble, strongly weathered, and moderately
weathered hard rocks. According to the characteristic of complex strata for the
metro section, the effective field penetration index(EFPI) which considers the
effect of chamber earth pressure is proposed, and the regularity of tunneling
parameter is analyzed. The results show the following.(1) The EFPI works better
than the field penetration index (FPI) in evaluating the difficulty of
surrounding rock cutting by TBM and distinction of soil and strongly weathered
hard rock. (2) EFPI is proportionally and linearly correlation to the strata
standard penetration number, and when tunneling in the soilweathered
rock strata,Log (EFPI)=2.3 can be used as the dividing standard of soil and
strong weathered rock. (3)Log (EFPI) is positively
correlated to Log (TPI), while Log (EFPI) is negatively correlated to the
propulsion speed v. The
characteristic points in soil layer are with great discreteness, while the
characteristic points in the transitional section of strong to moderately
weathered hard rock are with small discreteness. Function relationship among
Log (EFPI), Log (TPI), Log (EFPI)and v in the transitional section of strong to moderately weathered hard
rock is obtained by fitting. (4)If Log (EFPI)≤2.3, the excavation control should be focused on keeping the
stability of earth pressure; if Log (EFPI)>2.3,the
tunneling speed should be adjusted according to the value of EFPI to improve
tunneling efficiency.
HUANG Jihui, TANG Zhicheng, ZHANG Xiaohui, CHEN Xiaoyang, GUO Xiao
.
Stratigraphic Correlation of EFPI and Evolution
Regularity of Shield Tunneling Parameter In Complex Stratum
[J]. Tunnel Construction, 2021
, 41(S2)
: 215
-221
.
DOI: 10.3973/j.issn.2096-4498.2021.S2.027