To achieve largescale and high-precision geological
exploration for urban metro shield construction, a case study is conducted on
the Huizhou-Shenzhen intercity railway project using
distributed acoustic sensor (DAS) technology. The authors explore methods for
large-scale and detailed investigations of urban
underground bad geological bodies. First, the extended spatial autocorrelation
(ESPAC) method is applied to invert the properties of underground rock and soil
masses. By establishing a correlation between the dynamic strain measured by
acoustic fibers and the underground shear velocity field, information about
underground rock and soil properties, as well as the location and size of karst
caves are retrieved. The results are then systematically compared and verified
using data obtained from drilling and electromagnetic wave scanning. The
research findings indicate the following: The DAS-ESPAC
method effectively maps the shear wave velocity field up to a depth of 40 m. It
accurately identifies the stratification, type, size, and spatial distribution
of underground rock and soil masses based on the shear wave velocity
distribution. In addition, it verifies the boundary interface between silty
clay and limestone. The method achieves an inversion error for karst cave size
and distribution within 1 m. The exploration results align well with detailed
drilling data, supplementary exploration data, and geophysical exploration
data.
HONG Chengyu
,
ZHOU Ziping
,
LOU Zaiming
,
GUO Zhen
,
TAN Junqing
,
SU Dong
. Geotechnical Investigation
Method Based on Distributed Acoustic Sensors[J]. Tunnel Construction, 2025
, 45(1)
: 171
-178
.
DOI: 10.3973/j.issn.2096-4498.2025.01.014
