Dam-break flood has the characteristics of fast flow speed and large kinetic energy, which can increase the pore water pressure in slope and cause the slope deformation or even destruction. To determine the pore water pressure in slope under impact of dam-break flood, firstly, a novel approach for estimating the impact pressure of dam-break flood under condition of high Froude number is proposed based on equivalent hydrostatic pressure, and the accuracy of this approach is verified by wave flume test; then a simplified calculation method of pore water pressure is put forward based on microwave theory and Darcy's law. Finally, instability mechanism of a soil-rock mixed slope under dam-break flood is investigated, and the instability failure process of this slope is analyzed through field investigation. By constructing its geomechanical model, the slope stability is analyzed under impact of dam-break flood, and the results show that influence of dam break distance on the slope stability is significant in a certain critical range, and the maximum flood pressure distribution pattern changes from triangle to trapezoid with the increase of Froude number. The safety factor diminishes as the flood flow velocity increases, and the safety factors increase with the impact angle and internal friction angle increasing. These results can provide technical reference for landslide hazard risk assessment and emergency decision-making under dam-break flood action.

The technology of expansion fracturing with liquid CO2 (EFLCO2) has attracted increasing attention due to reduced vibration and damage. The disposable fracturing tube has been developed and is gradually replacing the Cardox tube. However, there is a lack of impact pressure testing of disposable tubes under real working conditions, selection of gas explosion design parameters, and systematic analysis of blasting vibration. This limitation has constrained the widespread application of disposable fracturing tubes in engineering. A joint monitoring of the pressure-time curves in the disposable tubes and boreholes was conducted. The rock-breaking effect of varying hole spacing parameters in the EFLCO2 design was analyzed, and a systematic study was carried out on the vibration peak value, frequency, and energy characteristics. The results show that (1) the pressure distribution characteristics, stress peak value, and duration in the disposable tubes are different from those of Cardox tubes, which show multi-peak distribution, low-pressure peak value, and short duration. The correlation between the pressure in the disposable tube, filling pressure, and liquid CO2 weight is established, and a theoretical calculation method for the borehole wall pressure is proposed; (2) The hole spacing in rocks of different hardness is suggested; and (3) At the same scale distance, the peak particle velocity (PPV) caused by EFLCO2 (PPVCO2) is significantly smaller than that caused by blasting (PPVexplosive). The ratio of PPVexplosive to PPVCO2 is a power function related to scale distance, and a distance-related zonality exist in this relationship. The frequency composition of the vibration signal caused by EFLCO2 is relatively simple with a narrow frequency band. Its PPV and energy are mainly concentrated in the low-frequency band. This research contributes to the optimization of disposable fracturing tubes, gas explosion design, and vibration hazard control. (c) 2024 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).