A substantial amount of research work and superlong
and deepburied horizontal drilling tests have been
conducted on the survey and design of the SichuanTibet
railway to study the feasibility of implementing superlong
horizontal drilling in the deepburied tunnel of the
SichuanTibet railway and the influence of horizontal
drilling on tunnel construction under complex geological conditions. According
to the tunneling index and drilling speed, the influence of superlong advance horizontal drilling on the construction period by
drilling and blasting and tunnel boring machine (TBM) methods is studied. The
results reveal the following: (1) In unit length, the better the geological
conditions of surrounding rock, the deeper the drilling depth and the faster
the tunneling speed, and the greater the influence of advance horizontal
drilling on the construction. (2) When advance horizontal drilling is carried
out 180 m behind TBM equipment in the surrounding rock of grades Ⅱ and Ⅲ, horizontal drilling progress is
difficult to keep up with the TBM′s construction speed, and the significance
of drilling for construction guidance is relatively small. Whereas in the
surrounding rock of grades Ⅳ and Ⅴ, it can catch up with the TBM construction tunnel face by a certain
distance, making it crucial to guide the tunnel construction in complicated
geological conditions such as when TBM construction is interrupted. (3) Longdistance continuous horizontal drilling at the shield has the
greatest impact on the tunnel construction, accounting for up to 85.11% of the
total. Comprehensive analysis shows that advance horizontal drilling is better
suited in the fault fracture zone, strong and highpressure
waterrich, karst, and other unfavorable geological
sections.
FU Wei
.
Influence of Horizontal Core Drilling on Tunnel
Construction Efficiency
of SichuanTibet Railway
[J]. Tunnel Construction, 0
: 1091
-1098
.
DOI: 10.3973/j.issn.2096-4498.2021.07.002
