IEEE Instrumentation & Measurement - September 2023 - 48

Morphological Reconstruction for
the Internal Structure of In-Situ SoilRock
Mixture Through Ultrasonic
Transmission Imaging Experiments
Huan Song and Xianjian Zou
A
iming at the problem of real-time visualization
analysis of the internal structural morphological
characteristics for in-situ soil-rock mixture, an experimental
system for the ultrasonic transmission imaging analysis
of soil-rock mixture was constructed, and a morphological reconstruction
method of internal structures for the in-situ
soil-rock mixture was proposed by using multiple ultrasonic
profile images. The system device and its analysis method
can obtain series of profile images of internal structures for insitu
soil-rock mixture. First, the image processing method is
used to analyze the characteristics of the imaging spots and
the bright bands of the internal structure, and the feature map
of the bright band in the image is obtained. Second, the ratio
of pixel points in the non-zero region of bright spot band to
whole pixel points in the feature map is obtained, and the ratio
is taken as the pore space ratio of the dual structure in the
soil-rock mixture. Last, the evaluation of pore space ratio and
the reconstruction of boundary structure morphology inside
the soil-rock mixture can be realized according to the feature
map and the pore space ratio of light spot and bright band. This
method effectively solves the real-time analysis and 3D reconstruction
problems of soil-rock mixture structures when the
simulation method is complicated and lacks the actual internal
profile image or the measured structure data.
Introduction
Soil-rock mixed stratum is often encountered in the construction
of urban near ground surfaces during slope geological
engineering [1, 2]. Before building construction, it is very important
to survey the stratum structure and obtain the internal
structure parameters to ensure the building safety. In domestic
and foreign studies, there are many research studies on
homogeneous structure, but there are fewer on mechanical
characteristics, seepage characteristics and engineering safety
of soil-rock mixture dual structure [3]-[5].
At present, research on the dual structure of soil-rock
mixture and its mechanical properties mainly focuses on
the change of boundary structure and the deformation failure
of the microstructure and morphological characteristics
48
of soil-rock mixture for homogeneous structure [6], as well
as the contact mechanism of the meso-structure of soil-rock
mixture and its macroscopic mechanical behavior, such as
studying the frictional contact mechanisms between inside
particles of soil-rock mixture [7]. However, there are many
spans of various non-homogeneous structures from the water
soil surface to the bottom of the rock mass, and there are
a lot of clay minerals or pores in the soil-rock mixture under
the action of water. Their meso-structures and mechanical
characteristics have been changed. Therefore, the dual structure
detection and interaction mechanism analysis between
internal structures in the soil-rock mixture are of great significance
[8]. To address these questions, the first problem is to
improve the dual structure detection method and obtain more
formation parameters. The traditional core sampling method
of geological exploration will inevitably damage the formation
samples during the drilling process. At the same depth,
the sample taking rate is low, and the amount of sampling is
small. The disturbed formation samples obtained can only be
used for a limited number of geotechnical tests, which will inevitably
lead to large fluctuation of formation data. To obtain
the internal structure of rock-soil mixture, magnetic resonance
imaging (MRI) is a commonly used method; however, the
method is confined to an indoor test bench, and the x-ray spectrum
on the tomographic reconstruction is also very complex.
The x-rays are also very harmful to humans. There is a lack of
a practical and effective on-site real-time observation system
and in-situ testing methods.
Ultrasonic imaging technology is a kind of applicable advanced
detection approach for both hole and surface, which
can penetrate the interior of the soil-rock mixture and obtain
the in-situ formation parameters [9]. Ultrasonic imaging detection
is used to observe the undisturbed strata around the
hole wall, which can accurately obtain the original strata structure.
Compared with the core sample, it is more authentic, and
the sampling range at the same depth is much larger than the
core sample. With the rapid development of ultrasonic imaging
technology, computer technology and image processing
technology, a variety of portable diagnostic measurement
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September 2023
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