The traditional vertical geological survey is often
impractical in urban areas with dense buildings and complex surface
environments. Therefore, directional drilling technology, which has already
reached a relatively high level of maturity in geology, coal mining, and oil extraction,
is introduced. Longdistance directional drilling is
arranged along the underground engineering axis in this approach, explicitly
using lateral hole drilling at critical geological points, and core samples at
regular intervals are extracted. The specific measurement is obtained while
drilling and comprehensive geophysical exploration is conducted in the drilling
hole along the set trajectory to understand the formation lithology and
geological structure of underground engineering area. Consequently, the
surrounding rock lithology and tunneling and supporting parameters are
determined. Based on the successful implementation of controlled track drilling
for a 660 m mainhole and two
330 m lateral holes in Guangzhou urban area, the core drilling at an interval
of 15~30 m is implemented and borehole acoustic wave and resistivity tests are
used as supplements. Finally, the drilling core samples are compared with the
results obtained through geophysical exploration to comprehensively assess the
engineering geological conditions within a certain range of the tunnel.
WANG Yonggang
,
SUN Honglin
,
HU Zhixin
,
WANG Yihong
,
LYU Weiwei
. Application of MultiBranch
Directional Drilling Technology for Tunnel Investigation[J]. Tunnel Construction, 2023
, 43(9)
: 1558
-1564
.
DOI: 10.3973/j.issn.2096-4498.2023.09.013
