GPR surveys for the prevention of karst risk in underground gypsum quarries

Caselle, Chiara; Bonetto, Sabrina Maria Rita; Comina, Cesare; Stocco, Stefano

doi:10.1016/j.tust.2019.103137

Cited by 36 publications

(15 citation statements)

References 29 publications

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“…In addition, karst caves, underground rivers, faults, joint fissures, and water-bearing structures ahead of the tunnel face are concealing, sudden, and destructive [18][19][20]. If the geological situations ahead of the tunnel face are not detected before excavation, blind excavation may cause great disturbance to some unstable rocks and even result in other serious geological disasters, such as water and mud inrush [21][22][23]. During the construction process, the longer the exposure time of the tunnel excavation surface, the more serious the rock mass is wetted by groundwater, which reduces the self-stabilizing ability of the rock mass.…”

Section: Introductionmentioning

confidence: 99%

Three-Dimensional Quantitative Recognition of Filler Materials Ahead of a Tunnel Face via Time-Energy Density Analysis of Wavelet Transforms

Zhang

et al. 2022

Minerals

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Advanced geological prediction of tunnels has become an indispensable task to ensure the safety and effectiveness of tunnel construction before excavation in karst areas. Geological disasters caused by unfavorable geological conditions, such as karst caves, faults, and broken zones ahead of a tunnel face, are highly sudden and destructive. Determining how to predict the spatial location and geometric size of unfavorable geological bodies accurately is a challenging problem. In order to facilitate a three-dimensional quantitative analysis of the filler material ahead of the tunnel face, a biorthogonal wavelet with short support, linear phase, and highly matching waveform of ground penetrating radar (GPR) wavelet is constructed by lifting a simple and general initial filter on the basis of lifting wavelet theory. A method for a time–energy density analysis of wavelet transforms (TEDAWT) is proposed in accordance with the biorthogonal wavelet. Fifteen longitudinal and horizontal survey lines are used to detect void fillers of different heights. Then, static correction, DC bias, gain, band-pass filtering, and offset processing are performed in the original GPR profile to enhance reflected signals and converge diffraction signals. A slice map of GPR profile is generated in accordance with the relative position of longitudinal and horizontal survey lines in space. The wavelet transform analysis of a single-channel signal of each survey line is performed by adopting the TEDAWT method because of the similar rule of the single-channel signal of GPR on the waveform overlay and the ability of the constructed wavelet basis to highlight the time-frequency characteristics of GPR signals. The characteristic value points of the first and second interfaces of the void fillers can be clearly determined, and the three-dimensional spatial position and geometric sizes of different void fillers can be obtained. Therefore, the three-dimensional visualization of GPR data is realized. Results show that the TEDAWT method has a good practical application effect in the quantitative identification of void fillers, which provides a basis for the interpretation of advanced geological prediction data of tunnels and for the construction decision.

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Section: Introductionmentioning

confidence: 99%

Three-Dimensional Quantitative Recognition of Filler Materials Ahead of a Tunnel Face via Time-Energy Density Analysis of Wavelet Transforms

Zhang

et al. 2022

Minerals

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“…In dams, tunnels and other rock engineering projects, the failure and instability of rock masses are usually caused by the opening, closing, expanding and connecting of internal defects. Holes and fissures are the most basic rock defects [7][8][9][10][11][12][13]. The different distributions of defects make the strength characteristics, deformation and failure law of rock more complex [14][15][16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

“…Among these studies, there have been many achievements in single defect research. Chen et al [23] studied a rock-like material which contained prefabricated parallel double fissures, studying how the fissures length difference and spacing influence the failure of specimens under Sustainability 2021, 13, 7090 2 of 16 uniaxial compression, and analysing them with fracture mechanics theory. Chen et al [24] studied the failure behaviour and mechanical properties of rock samples with holes of various shapes using the finite element method, determined four failure modes, and studied the crack propagation and the evolution of the stress field.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study of the Strength and Characteristics of Sandstone Samples with Combined Double Hole and Double Fissure Defects

Ning

Wang

et al. 2021

Sustainability

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To explore the failure mechanism of rock with holes and fissures, uniaxial compression tests of sandstone samples with combined double hole and double fissure defects were carried out using Particle Flow Code 2D (PFC2D) numerical simulation software. The failure behaviour and mechanical properties of the sandstone samples with combined double hole and double fissure defects at different angles were analysed, and the evolution results of the stress field and crack propagation were studied. The results show that with a decrease in fissure angle, the crack initiation stress, damage stress, elastic modulus and peak stress of the defective rock decrease, while the peak strain increases, and the brittleness of the rock is weakened. Rocks with combined double hole and double fissure defects at different angles lead to different failure modes, crack initiation positions and crack development directions. After uniaxial compression, both compressive stress and tensile stress concentration areas are produced in the defective rock, but the compressive stress concentration is of primary importance. The concentration area is mainly distributed around the holes and fissures and the defect connecting line, and the stress concentration area decreases with the decreasing fissure angle. This study can correctly predict the mechanical properties of rock with combined double hole and double fissure defects at different angles and provide a reference for actual rock engineering.

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“…Karst caves are a hotspot in the research of engineering geology in karst regions [14,15]. Many prospecting geophysical prospecting methods have been widely adopted to explore the development of karst caves [16][17][18][19]. Fruitful results have been achieved on the evaluation of roof stability of karst caves [20,21], providing a good reference for the research into the stability of karst foundations [22,23].…”

Section: Introductionmentioning

confidence: 99%

Dissolution Features of Karst Foundations at Different Depth Sections

Cao¹,

Tang²,

Liu³

et al. 2020

IJDNE

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The dissolution of karst foundations can be divided into rock surface dissolution and hole dissolution. The dissolution features of karst foundations at different depths must be clearly identified before taking proper karst treatment measures. In this paper, more than 200 engineering data samples are collected from typical carbonate karstic regions in southwestern China, and 12 most representative engineering site were picked out. The rock surface dissolution ratio, hole dissolution ratio, and total dissolution ratio were measured at each engineering site, and used to fit the relationship between rock surface dissolution ratio and hole dissolution ratio at different depth sections. The results show that the karst foundation can be split into three sections from top to bottom: rock surface dissolution section Ⅰ, composite dissolution section Ⅱ, and hole dissolution section Ⅲ. The three sections occur inevitably as the rock surface dissolution occurs naturally from the inside. The dissolution degree decreases exponentially with the growing depth, and the rock surface dissolution ratio drops faster than the total dissolution ratio. Moreover, the hole dissolution ratio per unit volume of rock decreases with the increase of depth. If the holes are not developed, the engineering sites will only have rock surface dissolution section; if the holes become more developed, the composite dissolution section will expand gradually and dominate site dissolution. At most locations, the hole dissolution ratios under the minimum elevation of rock surface are within 10%. Finally, it is suggested that the final elevation of the drilling holes must be controlled above the minimum elevation of rock surface. The research results shed new light on the mitigation of dissolution of karst foundations.

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GPR surveys for the prevention of karst risk in underground gypsum quarries

Cited by 36 publications

References 29 publications

Three-Dimensional Quantitative Recognition of Filler Materials Ahead of a Tunnel Face via Time-Energy Density Analysis of Wavelet Transforms

Three-Dimensional Quantitative Recognition of Filler Materials Ahead of a Tunnel Face via Time-Energy Density Analysis of Wavelet Transforms

Numerical Study of the Strength and Characteristics of Sandstone Samples with Combined Double Hole and Double Fissure Defects

Dissolution Features of Karst Foundations at Different Depth Sections

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