Abstract
This paper explores a new approach for assessing the stability of a hazardous rock block on a slope using vibration feature parameters. A physical model experiment is designed in which a thermally sensitive material is incorporated into the potential failure plane of the hazardous rock, and the complete process of hazardous rock collapse caused by strength deterioration is simulated by means of constant‐temperature heat transfer. Moreover, the vibration response of the hazardous rock is monitored in real time by laser vibrometry. The experimental results show that five vibration feature parameters, including the mean frequency, the center frequency, the peak frequency, the mean frequency standard deviation, and the root mean square frequency, are well‐correlated with rock stability. Furthermore, through principal component analysis, the five vibration feature parameters are synthesized into a principal component factor (PCF) as a representative assessment parameter. The results of the analysis demonstrate that the variation in the PCF exhibits three characteristic stages, i.e., “stationary‐deviation‐acceleration,” and can effectively identify the stability evolution trend and collapse precursor behavior of hazardous rock block.
Highlights
Hazardous rock, located on a steep slope and surrounded by weak failure planes, is a rock block with little stability (Figure 1). e collapse of rocks is a significant natural hazard in mountainous areas
Many researchers have reported by using extensometer, photogrammetry, global positioning system (GPS), light detection and ranging (LiDAR), ground-based interferometry synthetic aperture radar (GBInSAR), and other technical approaches to observe displacement to locate hazardous rocks [7,8,9,10,11,12,13]; in general, hazardous rock collapses at low strain and tertiary creep develop very rapidly [14], which makes it difficult to use displacement to monitor the strength deterioration in a rock mass and to predict its tendency towards stability development [15]
E scree plot obtained by principal component analysis is shown in Figure 10. e abscissa is the component number, and the ordinate is the eigenvalue. e eigenvalue of the first principal component is larger (>1) than the others, and the variance contribution reached 92.717%, indicating that most of the information of the vibration feature parameters is represented. erefore, the load matrix L of the first principal component is adopted as the weight of each vibration feature parameter as follows: L [−0.455, 0.448, 0.447, 0.449, −0.435]T
Summary
Hazardous rock, located on a steep slope and surrounded by weak failure planes, is a rock block with little stability (Figure 1). e collapse of rocks is a significant natural hazard in mountainous areas. The stability assessment of rock blocks is based on empirical judgments gained by visual inspection of rock mass structures. Many researchers have reported by using extensometer, photogrammetry, global positioning system (GPS), light detection and ranging (LiDAR), ground-based interferometry synthetic aperture radar (GBInSAR), and other technical approaches to observe displacement (or strain) to locate hazardous rocks [7,8,9,10,11,12,13]; in general, hazardous rock collapses at low strain and tertiary creep develop very rapidly [14], which makes it difficult to use displacement (or strain) to monitor the strength deterioration in a rock mass and to predict its tendency towards stability development [15]
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