An experimental study is performed using the semiairborne
transient electromagnetic method with ground excitation and airborne reception
for exploring tunnels under complex terrain conditions in southwest China.
Furthermore, the optimization of the route design and data acquisition process
is achieved by implementing an airborne transient electromagnetic method, which
utilizes a 〖WTBX〗α〖WT５《TNR》〗trimmed mean filter to remove
astroelectric and motion noise based on the polynomial fitting method.
Moreover, the data superposition method and time window integration parameters
are determined, full domain apparent resistivity is calculated, threedimensional(3D) imaging of the probing area is achieved, the apparent
resistivity of the tunnelfilled karst development area
is characterized, and probing results are comprehensively interpreted. The
results are validated through field application of the proposed method in the
Fenghuan #2 tunnel. The main conclusions obtained from the study are as
follows. (1) The semiairborne transient
electromagnetic method can accurately detect the scope and depth of waterbearing fracture zones, karst development zones, and other
undesirable geological structures; furthermore, it can detect the geological
risk areas of tunnels in advance and acquire the distribution characteristics
of underground electrical conductivity, demonstrating stronger terrain
adaptability and higher detection efficiency in the tunnel survey of karst mountainous
areas compared with the traditional groundbased
physical exploration method. (2) The geological anomalies deduced from the 3D
visual resistivity imaging and key location slicing outcomes strongly concur
with the anomalies exposed through tunnel excavation. Thus, the proposed method
has the potential to offer technical support for designing tunnel karst
disposal plans to ensure safe construction, which can effectively avoid
casualties and property losses due to hidden karst hazards during tunnel construction.
ZHENG Huanyu
,
HU Jie
,
PAN Zhijun
,
CHEN Xinpeng
,
SUN Hanwu
,
WANG Yongxin
,
SUN Huaifeng
. Application of SemiAirborne Transient
Electromagnetic Exploration Technology in Fenghuang #2
Tunnel[J]. Tunnel Construction, 2023
, 43(9)
: 1573
-1582
.
DOI: 10.3973/j.issn.2096-4498.2023.09.015
