The mechanism failure of massive perilous rock should consider the interaction among perilous rock masses. Study on the stability of adjacent perilous rock from the excitation wave, which is produced by the perilous rock mass at the collapse instantaneousness, has important significance. Focusing on the falling-type perilous rock, physical model of perilous rock with excitation wave is considered and the stress characteristics for the excitation wave of perilous rock avalanche on dominant fissure with normal incidence is analyzed. Based on the fracture mechanics, a method to calculate the combined stress intensity factors of dominant fissure under falling excitation action of perilous rock is established. As the instance results showed, two cites of nature and rainfall, the stability coefficient are both reduce, specially in the horizontal, stability coefficient reduced by about 10% respectively, while in vertical about 2%. The results provided some scientific progresses disasters prevention and mitigation of perilous rock.
Rockfall is one of common geological disasters in the mountainous area. The experiment gained the impact waves for cushion soil mass contained 12density, 4 soil-rock ratio, 4 cushion obliquity, 3 moisture content, 3 rockfall quality, 5 height of rock fall. Used the wavelet theory to deal with the experiment waves, analyzed the experiment results: with rock’s mass, the height and density increased, the impact force is increasing, or the impact force is decreasing with the moisture content and cushion inclination increasing. The impact force spreads from the point of rockfall to all directions. The impact force data of the experiment is a little large than others, so this method provides a gist for choosing the prevention and cure measure for rockfall.
Shed-tunnel is one of common prevention measures along the highway. First, denoised the rockfall impact signal when the rock impact the ordinary shed-tunnel and the energy dissipation shed-tunnel by the wavelet theory. The calculation result indicated that the wavelet theory’s denoise effect is very good. Then, pick-up each frequency band’s the rockfall impact signal, and analysed the energy for each frequency band’s impact signal. The result indicated that the energy dissipation shed-tunnel’s impact energy concentrate in the low frequency part. There are only 0.4% impact energy in the high frequency part. Besides, the energy dissipation shed-tunnel’s impact energy in the low frequency part is higher than the the ordinary shed-tunnel, and the energy dissipation shed-tunnel’s impact energy depressed velocity when the impact frequency increase is fast than the ordinary shed-tunnel. So the energy dissipation shed-tunnel’s design must consider the low frequency impact,and could ignore the high frequency impact.
Shed-tunnel is one of common prevention measures along the highway. Through the wavelet theory we denoised the rockfall impact signal when the rock impact the ordinary shed-tunnel and the energy dissipation shed-tunnel. And then we evaluated the wavelet theory’s denoise effect by the signal-to-noise ratio. The calculation result indicated that the denoise effect is very good. At last, through the autocorrelation analysis and time-frequency analysis for the rockfall impact signal, it was found that the ordinary shed-tunnel’s impact signals didn’t have obvious frequency and the frequency contained many component,but the energy dissipation shed-tunnel’s impact signals had obvious frequency. So the energy dissipation shed-tunnel’s impact signals had a relatively fixed cycle and frequency. The received frequency of rockfall impact by the time-frequency analysis could provide the basis for the design of energy dissipation shed-tunnel’s natural frequency.
Soil-water characteristic curve(SWCC)is closely relevant to two main factors which are structure and moisture content. According to the two factors the values of matrix suction of 45 groups experimental specimens within different moisture content and soil -stone ratio of unsaturated soil are get through filter paper method. Date analysis shows that relation between matrix suction and soil-stone ratio at different moisture states is of different characteristics. Relation between matrix suction and water content is notably nonlinear. Distribution of matrix suction is curved surface in the moisture and soil-stone ration state space which is the function of water content and soil-stone ratio, in which the axial plan is parallel to the axis of soil-stone ratio.At low water content,the matrix suction on the moisture content change is very sensitive, at high moisture content and closed to saturation stage matrix suction hardly changes along with water content and soil-stone ratio change. The curved surface which Located in the middle section ,the matrix suction on the change of water content are more sensitive, reduced with water content increasing; and in this phase the matrix suction is insensitive to the variation of soil-stone ratio. Finally, it is concluded that the saturation to describe the soil water characteristic curve is a bad choice, with moisture to depict the so. In contrast, directly using the water content to describe the soil water characteristic curve is better.
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