It is essential to choose a suitable breakthrough mode
for the docking section between the shield and mined sections. The major
procedures of breakthrough mode by shield and mining methods are presented to
handle this issue, and the idea of shield dismantling before a breakthrough is
proposed for the docking section constructed using mining technique. The shielddismantling
process under the surrounding rocks of grades Ⅱ to Ⅴ and the breakthrough process using the mining method under the
surrounding rocks of grades Ⅲ and Ⅳ are simulated considering the surrounding rock grade as a variable.
By comparing the features of the two breakthrough modes and numerical
calculation findings, conclusions are drawn as follows: (1) The shield
dismantling before the breakthrough can efficiently enhance the turnover
utilization rate of the shield, avoiding machine jam and minimizing the impact
of blasting. (2) The numerical calculation results of shield dismantling in
advance reveal that the development of the plastic zone and deformation in
neighboring rocks of grades Ⅱ to Ⅳ are not clear, while that of grade Ⅴ increases rapidly, indicating that the shield dismantling in advance is
feasible in surrounding rocks of grades Ⅱ to Ⅳ and not feasible in surrounding rock of grade Ⅴ. (3) The numerical results of tunnel breakthrough by mining
technique in surrounding rocks of grades Ⅲ and Ⅳ indicate that the deformation rapidly increases at docking section
in surrounding rock of grade Ⅳ; thus, appropriate
reinforcement measures should be adopted. Finally, the breakthrough mode
selection method for docking section between shield and mined sections
considering surrounding rock grade are summarized and confirmed in practical
engineering.
SUN Feixiang
,
PENG Zhengyong
,
ZHOU Jianjun
,
YANG Zhenxing
,
ZHANG Jichao
,
TANG Zongxiong
. Study on Breakthrough Modes in Docking Section between
Shield and Mined Sections Considering Rock Mass Classification[J]. Tunnel Construction, 2021
, 41(8)
: 1336
.
DOI: 10.3973/j.issn.2096-4498.2021.08.009
