Twodimensional models are insufficient for capturing the three-dimensional(3D) characteristics of voids
behind tunnel linings, primarily due to the interference caused by
reinforcement during traditional ground penetrating radar image processing.
Additionally, conventional data processing methods are computationally
inefficient and have limited accuracy. To address these challenges, the authors
integrate average elimination, exponential gain, and time-zero correction techniques to develop the gprMax interference
elimination method. The proposed method leverages the temporal variation of
radar signals within two-way travel windows and uses
piecewise function calculations to enhance computational performance. The
feasibility of the proposed method is validated through forward simulations. A
3D model of the voids behind tunnel linings is constructed using gprMax software
based on the finite-difference time-domain method to align with real-world
grouting conditions and detection processes. The gprMax interference
elimination method is used to optimize the imaging results of the forward
simulation under varying conditions. The analysis of the imaging
characteristics yields the following findings: (1) The forward simulation
results using the gprMax interference elimination method closely align with the
measured results from model tests of circular cavity structures embedded in
indoor concrete slabs. (2) On horizontal survey lines, the rectangular void
signal appears as a "concave" shape, whereas on vertical survey
lines, it resembles the characteristics of direct waves. The size and burial
depth of voids can be derived from the 3D feature maps. (3) The gprMax
interference elimination method significantly enhances the electromagnetic
signal strength of voids at greater depths. In summary, the proposed gprMax
interference elimination method improves the data processing efficiency for
voids behind tunnel linings while maintaining calculation accuracy and
precision.
LU Dechun
,
QIN Wei
,
GUO Caixia
,
LI Jiulin
,
DU Xiuli
. Optimizing Imaging
Characteristics of Voids Behind Tunnel Linings
Using gprMax Interference Elimination Method[J]. Tunnel Construction, 2024
, 44(10)
: 1928
-1940
.
DOI: 10.3973/j.issn.2096-4498.2024.10.002
