Study of a borehole panoramic stereopair imaging system

Wang, Chuanying; Wang, Yiteng; Zou, Xianjian; Han, Zhengsheng; Sheng, Zhong

doi:10.1016/j.ijrmms.2018.01.040

Cited by 15 publications

(8 citation statements)

References 26 publications

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“…A borehole optical imaging system is an effective, convenient, and practical drilling investigation technology. e interior status of the borehole can be directly observed from optical images [23,24]. To establish the spatial coordinate system of the drilling hole, the diameter of the borehole must be known, and the shape of the borehole should be a standard cylinder.…”

Section: Pile Integrity Detectionmentioning

confidence: 99%

Instability Analysis of a Low‐Angle Low‐Expansive Soil Slope under Seasonal Wet‐Dry Cycles and River‐Level Variations

Wang

Yuan

2020

Advances in Civil Engineering

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There were a small amount of obvious offsets at the bearing of bridge piers built on an artificial gentle canal bank terrace and many tensile cracks visible at the surface of the mortar block stones covering the terrace soil in several years following construction. To determine these reasons, a comprehensive site investigation and a wide variety of tests were implemented, which included geophysical tests, in situ tests, laboratory tests, pile integrity detection, and numerical analysis with the finite element method (FEM). The results revealed that the soil of the low-angle slope was the potentially low-expansive clay soil. The reduction in soil shear strength deriving from seasonal wet-dry cycles and river-level variations led to the instability and failure of the low-angle low-expansive soil slope, which triggered the collapses of the soil slope and lots of fractures in the piles of the bridge foundation. The typical characteristics of the instability and failure of the low-angle low-expansive soil slope were tractional detachment and slow sliding.

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Section: Pile Integrity Detectionmentioning

confidence: 99%

Instability Analysis of a Low‐Angle Low‐Expansive Soil Slope under Seasonal Wet‐Dry Cycles and River‐Level Variations

Wang

Yuan

2020

Advances in Civil Engineering

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“…The structure and deployment of IR in a panoramic system is critical for producing high quality panoramic images. 5 Panoramic systems consist of an IR objective system, a transferring image optical system, an IR receiver lens and detectors. A cobeam prism cemented together with the four right-angle prisms lies in the center position of the sphere.…”

Section: Structural Design Of the Panoramic Systemmentioning

confidence: 99%

“…PI with 360 deg azimuth and 90 deg elevation angles was made possible with a five-channel panoramic optical system employing five spatially distributed objective lenses, each exceeding an FOV of 90 deg. 5,6 In this work, we present a four-channel dual-band IR PI optical system based on spatially distributed multiple lenses to capture scenes at different angles which are then combined to form a panorama. A double imaging configuration was incorporated into the system that resulted in a large aperture, increased field of view (FOV), and high resolution.…”

Section: Introductionmentioning

confidence: 99%

Optical system design of four-channel dual-band infrared panoramic imaging

2019

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In order to reduce the volume of a panoramic optical system, a four-channel infrared dual-band panoramic imager was designed using spatial multicamera image mosaicking. Each optical system of the imaging channel was designed in a double imaging configuration with an F-number of 2, working bands of MWIR 3 to 5 μm and LWIR 8 to 12 μm, and a full field of view (FOV) of 122 deg. By adopting refractive-diffractive hybrid optical elements and introducing aspheric designs, the system was made to achieve temperature compensation from −40°C to 60°C by means of optical passive athermalization. Results indicate that the system attained almost 100% cold stop efficiency. At the Nyquist frequency of 18 lp/mm, the modulation-transfer-function (MTF) of the MWIR system was higher than 0.70 at the edges of the FOV, whereas the MTF of LWIR system was greater than 0.35 for the same condition, both approaching the diffraction limit.

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“…Because of its extensive use in the determination of in situ stresses in rock mass at great depths, the hydraulic fracture test (Haimson 1978;Bjarnason et al, 1989;Tunbridge et al, 1989;Ljunggren et al, 2003;Haimson and Cornet, 2003;Zhao et al, 2005;Subrahmanyam, 2019;Singh and Sahoo, 2000;Gowd et al, 1986;Ulf Lindfors, 2007;Qitao et al, 2016) was utilised to study the itabirite rocks found in the Brazilian Ferriferous Quadrilater. In addition, the study interpreted the borehole images, because it was demonstrated that this is important to determine the effects of hydrofracturing on the in situ stress measurement (Li et al, 2013;Wang, 2018;Han et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

Hydrofracturing in Situ Stress Measurements in Itabirite Brazilian Ferriferous Quadrilater, and their Limitations

Penido¹,

Figueiredo

Assis

et al. 2021

Preprint

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This article presents a first attempt to carry out measurements (magnitudes and orientations) of the in situ stress in itabirite rocks in the region of the Brazilian Ferriferous Quadrilater obtained by hydraulic fracture tests at a depth of 399 m. Previous studies available in this rock mass consider estimated values of k index (Sh / Sv), and it is not a practice adopted to carry out in situ stress tests in this region and rockmass to support geotechnical analysis. The area of study is located at a depth of 500 m in a pit; therefore, the determination of the in situ stress distribution is very important to assess the stability of the mining open pit. The activities, from the planning to the execution of the tests, and the results are presented. The rock mass under study shows the presence of different geological structures, such as banding and foliation, which resulted in difficulties with performing the tests, and only 12.5% of the tests were successful. The results contribute to understanding the strains and stresses induced by mining activities in slopes in the Brazilian Ferriferous Quadrilater and their impacts on surrounding structures. For a better determination of the regional in situ stresses in the rock mass of the Brazilian Ferriferous Quadrilater, it is recommended to perform hydraulic tests on pre-existing fractures.

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Study of a borehole panoramic stereopair imaging system

Cited by 15 publications

References 26 publications

Instability Analysis of a Low‐Angle Low‐Expansive Soil Slope under Seasonal Wet‐Dry Cycles and River‐Level Variations

Instability Analysis of a Low‐Angle Low‐Expansive Soil Slope under Seasonal Wet‐Dry Cycles and River‐Level Variations

Optical system design of four-channel dual-band infrared panoramic imaging

Hydrofracturing in Situ Stress Measurements in Itabirite Brazilian Ferriferous Quadrilater, and their Limitations

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