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循环爆破振动作用下含断层边坡稳定性计算方法

Calculation of slope stability of fault-containing slopes under the action of cyclic blast vibration

  • 摘要: 为准确量化和预测爆破振动长期作用下含断层边坡稳定性演变规律,实现露天矿安全高效可持续开采。以某露天矿为工程背景,采用现场测振试验、数值计算探究了爆破地震波在时间与空间维度的动态特征,研究了爆破地震波水平与垂直方向传播衰减规律,阐明了高程放大效应及断层隔振效应;采用霍普金森压杆冲击试验,研究了循环爆破冲击作用下边坡岩土体裂纹扩展与损伤劣化规律,确立了爆破振动强度、次数与岩体内部损伤之间的定量关系,建立了边坡岩土体动态损伤劣化数学模型;应用FLAC3D数值模拟研究了爆破振动作用下边坡动力响应特征,分析了边坡的潜在滑坡模式和失稳演化机理,提出了爆破振动作用下含断层边坡稳定性计算方法,定量分析了爆破振动对边坡稳定性的影响,预测了边坡可承受爆破振动次数。结果表明:爆破振动对边坡稳定性影响较大,爆破振动作用下边坡最大动应力响应与单响药量、高程差呈正相关关系,与爆心距呈负相关关系;随爆破振动最大动应力增大、爆破次数增多,损伤参量呈指数函数变大,边坡动−静力安全系数的降低率呈幂函数增大趋势。结合工程实例,验证了爆破振动作用下含断层边坡稳定性计算方法的合理性,为类似矿山边坡稳定性评价提供了新视角。

     

    Abstract: In order to accurately quantify and predict the evolution of slope stability of fault-containing slopes under the long-term effect of blasting vibration, and to realize the safe, efficient and sustainable mining of open-pit mines. Taking an open-pit mine as the engineering background, the dynamic characteristics of blasting seismic waves in time and space dimensions are investigated by on-site vibration testing and numerical calculations, and the propagation and attenuation laws of blasting seismic waves in the horizontal and vertical directions are studied to elucidate the mechanism of elevation amplification effect and the vibration isolation effect of faults; Hopkinson compression rod impact test is used to study the crack expansion and damage deterioration laws of slope rock and soil bodies under the effect of cyclic blasting impacts. Established the quantitative relationship between the intensity and frequency of blasting vibration and the internal damage of the rock body, and established a dynamic damage degradation mathematical model of the slope geotechnical body; applied FLAC3D numerical simulation to study the characteristics of the dynamic response of the slope under the action of blasting vibration, and analyzed the potential landslide mode of the slope and the mechanism of destabilizing evolution, and put forward the calculation method of the stability of the slope containing faults under the action of blasting vibration, and analyzed the effect of the blast vibration on the stability of the slope quantitatively. Quantitatively analyze the effect of blasting vibration on slope stability, predict the number of blasting vibration that the slope can withstand. The results show that: blasting vibration has a greater impact on slope stability, the maximum dynamic stress response of the slope under the action of blasting vibration is positively correlated with the amount of single shot, elevation difference, and negatively correlated with the center of the blast distance; with the increase of the maximum dynamic stress of blasting vibration and the number of blasts, the damage parameter is an exponential function of the damage parameter is larger, and the rate of reduction of the dynamic-static coefficient of safety of the slope is a trend of the power function of the increase. Combined with engineering examples, it verifies the reasonableness of the calculation method of slope stability of fault-containing slopes under the action of blasting vibration, and provides a new perspective for the evaluation of slope stability of similar mines.

     

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