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The study of rock burst tendency of rock masses with different sizes plays a key role in the prevention of rock burst. Through theoretical analysis, it is proposed that uniaxial compressive strength and deformation modulus ratio are the key mechanical parameters affecting rock burst occurrence. In order to find out the size effect of uniaxial compressive strength and deformation modulus ratio, theoretical analysis and uniaxial compression experiment are carried out on rock samples with different heights, different cross-sectional areas and different volumes. The results show that the smaller the uniaxial compressive strength is, the larger the deformation modulus ratio is, and the more likely rock burst are to occur. On the contrary, rock burst is still not easy to generate. The uniaxial compressive strength of rock samples with different heights, different cross-sectional areas and different volumes increases with the increase of rock sample size. The deformation modulus ratio of rock samples with different heights and different volumes shows an upward trend on the whole, while that of rock samples with different cross-sectional areas shows a downward trend on the whole. The fracture forms of rock are analyzed using the energy conversion law in the process of deformation and failure for three kinds of rock with different shapes and sizes. [ABSTRACT FROM AUTHOR]

Abstract The study of rock burst tendency of rock masses with different sizes plays a key role in the prevention of rock burst. Through theoretical analysis, it is proposed that uniaxial compressive strength and deformation modulus ratio are the key mechanical parameters affecting rock burst occurrence. In order to find out the size effect of uniaxial compressive strength and deformation modulus ratio, theoretical analysis and uniaxial compression experiment are carried out on rock samples with different heights, different cross-sectional areas and different volumes. The results show that the smaller the uniaxial compressive strength is, the larger the deformation modulus ratio is, and the more likely rock burst are to occur. On the contrary, rock burst is still not easy to generate. The uniaxial compressive strength of rock samples with different heights, different cross-sectional areas and different volumes increases with the increase of rock sample size. The deformation modulus ratio of rock samples with different heights and different volumes shows an upward trend on the whole, while that of rock samples with different cross-sectional areas shows a downward trend on the whole. The fracture forms of rock are analyzed using the energy conversion law in the process of deformation and failure for three kinds of rock with different shapes and sizes.

The consequences of landslide waves are far beyond the landslide itself that has attracted widespread attention. The prediction and evaluation of this kind of disaster has always been difficult, and the precise description of landslide surge motion characteristics and energy conversion law is the key and premise to solve the problem. In this paper, we use gravel to mimic granular landslide and establish a 3D landslide wave model in a rectangular flume, aiming to analyze how the landslide volume, velocity and water depth affect landslide accumulation, wave characteristics and energy conversion. The results show that (1) the waves generated by solid impacting the water are affected by the landslide size and shape. Slides with larger thickness and faster speed tend to produce nonlinear transition wave, and thin and slow slides generally produce nonlinear oscillation wave. (2) The volume effect and velocity effect based on the test reveal that the surge scale of a certain water depth is positively correlated with the landslide volume and velocity. The water depth effect explains the differences of waveform and velocity under a certain wave energy. Statistic results show that under the shallow water conditions, surge height on average is 67% higher and wave speed on average is 51.17% higher than those under the deep water conditions. (3) The conversion rate between landslide energy and wave energy ranges from 1.00% to 3.07%. 3D experiments encounter more energy dissipation due to diffusion and its conversion rate is lower than that in the 2D experiments. This study discusses the kinematic characteristics of granular landslide, first wave generation, propagation and inundation, and proposes the basic law of energy conversion between landslide and water. It id of certain value and significance for landslide wave hazard prevention and mitigation.

Landslide-tsunami formed by landslide impacting into water severely threatens the life and property safety of residents along coastal areas. The slide impact angle of landslide (α) is an essential parameter in landslide-tsunami prediction. Many studies have discussed the response laws of formation features of landslide-tsunami to the comprehensive effect of α and several other factors. However, the influencing laws of α on landslide-tsunami features vary and are even contradictory among different studies. To determine the independent effects of α on wave generation, this study used a numerical simulation correction on the correction utilized smoothed particle hydrodynamics (SPH) method, which verified the efficacy of SPH method in simulating landslide-tsunamis. Next, three groups of landslide-tsunami numerical simulation tests under different α (10°, 20°, and 30°) were implemented to analyze the influencing laws of α on water motion features, water occupation by the landslide, and energy conversion law thoroughly. Results demonstrate that the SPH method could simulate the generation and propagation of landslide-tsunami well, achieving a relatively high simulation accuracy. The landslide and water movements in the three groups of numerical simulations are similar. As α increases from 10° to 30° successively, the rate of water occupation by the landslide decreases gradually, but the volume of water occupied by the landslide increases. The maximum occupational volume reaches 7.91 times as that of landslide. After the landslide enters the water, the energy attenuation rate increases with the increment of α, and it reaches the lowest at α = 10°. Generally, with α increasing, the amplitude of the first wave decreases, while the amplitude of the second wave increases. The proposed conclusions provide some references to constructing the landslide-tsunami prediction model. [ABSTRACT FROM AUTHOR]

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