In current engineering and
research, the indices of cross-sectional
deformation extracted from point clouds are primarily convergent deformation,
which can hardly reflect the deformation characteristics of sectionally
continuous deformation properties of shield tunnel linings under the action of
a joint. To fully extract the cross-sectional
deformation characteristics from point clouds, a deformation characterization
method, which takes joints as boundary to fit each segment separately in a
polar coordinate system using Fourier functions, is proposed. The fitted curves
of each segment are then meshed based on the same density, and the node
coordinates are tracked to derive the displacement field of each segment. Full-scale experiments and numerical models are used to validate the
reliability of this method. In addition, theoretical analysis and numerical
experiments are conducted to examine the influence of key factors (such as the
types of fitting functions, influence of measurement errors, and selection of reference
system) on deformation extraction results. The findings reveal the following:
(1) The higher the order of the Fourier function used for fitting, the more
detailed the fitting of the segment lining profile. (2) Under the effect of
measurement errors, the application of high-order
Fourier functions is susceptible to overfitting, which results in an increase
in the deformation extraction error. (3) The proposed method shows its effect
and feasibility in actual shield tunnel engineering.
ZHANG Yumeng
,
WEI Gang
,
LIU Xian
. A Cross-Sectional Deformation Tracking Method for Laser Scanning Point Clouds of Shield Tunnel
Linings[J]. Tunnel Construction, 2024
, 44(9)
: 1852
-1862
.
DOI: 10.3973/j.issn.2096-4498.2024.09.014
