Engineering and Technological Sciences
Abstract
To address the issues of low work efficiency, high safety risks, and blind spots in the investigation of high and steep unstable rock masses during survey operations, this study takes the No. 1 high-position unstable rock mass of a hydropower project as an example. By utilizing close-range photogrammetry and ground-penetrating radar technologies, a survey system specifically designed for high and steep unstable rock masses was established. Technical means were employed to construct a three-dimensional oblique photography model of the unstable rock mass, accurately identifying its boundary conditions and engineering geological characteristics. Based on the acquired data, the instability mechanism and failure modes of the unstable rock mass were analyzed, and stability evaluations were conducted.
The results indicate that the No. 1 unstable rock mass has a thickness of approximately 14.1 m, a length of about 27.1 m, a maximum concave rock cavity depth of 4.6 m, and a volume of 2210 m³, classifying it as a large unstable rock mass. The development depth of the trailing edge tensile cracks ranges from 7.6 to 9.0 m, with a failure mode categorized as toppling. Under natural, seismic, and heavy rainfall conditions, the stability coefficients of the unstable rock mass are 1.16, 1.08, and 1.04, respectively, corresponding to stable, basically stable, and marginally stable states.
The non-contact measurement technique of oblique photography and the ground-penetrating radar technique for detecting tensile cracks compensate for the limitations of single-technology information acquisition. These methods resolve the problems of low efficiency, high safety risks, and blind spots associated with traditional survey methods, providing new ideas and approaches for the identification and detection of high and steep unstable rock masses. This study offers valuable references for the survey and evaluation of similar high and steep unstable rock masses.
Full Text
Three-Dimensional Model Construction and Stability Analysis of Unstable Rock Masses Based on Close-Range Photogrammetry and Ground Penetrating Radar Technology
OU Anfeng¹, WU Shuyu¹, YANG Jinjun¹, YU Jiasong¹, HOU Shuai²
¹ PowerChina Guiyang Engineering Corporation Limited, Guiyang, Guizhou 550081, China
² PowerChina Power Investment Group Co., Ltd., Lanzhou, Gansu 730030, China
Abstract
To address the issues of low work efficiency, high safety risks, and survey blind spots in the investigation of high-steep unstable rock masses, this study takes the No. 1 high-position unstable rock mass in a hydropower project as an example. By employing technologies such as close-range photogrammetry and ground-penetrating radar, a survey system specifically designed for high-steep unstable rock masses is established. Using technical means, a three-dimensional oblique photography model of the unstable rock mass is constructed to accurately identify its boundary conditions and engineering geological characteristics. Based on the acquired data, the instability mechanism and failure modes of the unstable rock mass are analyzed, and stability evaluations are conducted.
The results indicate that the No. 1 unstable rock mass has a thickness of approximately 14.1 m, a length of about 27.1 m, a maximum concave rock cavity depth of 4.6 m, and a volume of 2210 m³, classifying it as a large unstable rock mass. The development depth of the trailing edge tensile cracks ranges from 7.6 to 9.0 m, and the failure mode is identified as toppling. Under natural, seismic, and heavy rainfall conditions, the stability coefficients of the unstable rock mass are 1.16, 1.08, and 1.04, respectively, corresponding to stable, basically stable, and marginally stable states.
The non-contact measurement technique of oblique photography and the ground-penetrating radar technique for detecting tensile cracks compensate for the limitations of single techniques in information acquisition. These methods address the problems of low work efficiency, high safety risks, and survey blind spots associated with traditional investigation methods, providing new ideas and approaches for the identification and detection of high-steep unstable rock masses. This study offers valuable references for the investigation and evaluation of similar high-steep unstable rock masses.
Keywords: close-range photogrammetry; ground-penetrating radar; unstable rock mass; crack development depth; stability
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This version posted 2025-09-02.