The mudstonesandstone interbedded tunnel
is prone to large deformation, thus the reasonable support timing is extremely
important. Study is conducted on the support timing and total displacement
inversion of the Huipaishan tunnel of ChinaLaos
railway in mudstonesandstone interbedded strata.
First, the engineering characteristics of the rock mass are studied using
triaxial compression test, and the mechanical parameters of the rock mass are
modified based on the HoekBrown strength criterion to
provide the basis for the later numerical calculation. Then, through derivation
of the total displacement, the relationship between the total displacement and
the measured displacement is obtained based on field monitoring data. Finally,
the relationship between the crown settlement and the radius of the plastic
zone is obtained using numerical simulation, and the characteristic points are
found to determine the timing of the primary support and the strengthening
support. According to the relationship between the measured displacement and
the total displacement, the optimum support timing based on the field
monitoring data is obtained. The results show the following: (1) The condition
of mudstonesandstone interbedded surrounding rock is
poor, and the mechanical index parameters are about half lower than that of
singlecomponent surrounding rock. (2) The measured
displacement accounts for 60%-70% of the total displacement, and the
relationship between the measured displacement and the total displacement is
obtained. (3) The tunnel needs to be supported with the excavation, and when
the onsite monitoring crown settlement reaches 170 mm
and there is no convergence trend, the support measures should be strengthened.
XU Jianjun
. Support Timing of Mudstone-Sandstone
Interbedded Tunnel in China-Laos
Railway Based on Displacement Inversion[J]. Tunnel Construction, 2023
, 43(S2)
: 129
-135
.
DOI: 10.3973/j.issn.2096-4498.2023.S2.014
