地震作用下顺层边坡破坏机制研究

Study on Failure Mechanism of Bedding Slope under Earthquake

摘要: 为探究顺层边坡在地震作用下的动力响应，设计并制作了坡角为45˚、岩层倾角为30˚的顺层边坡模型，进行了数值模拟，分析边坡动力响应规律和HHT特征，研究边坡失稳机理和破坏过程。试验结果表明：在地震作用下，边坡表现出明显的“高程效应”和“趋表效应”，即坡体的加速度放大系数会沿着高程和水平距离的增加出现增加趋势；软弱面是顺层边坡中的薄弱点，软弱面上部最先破坏。随着幅值增大，顺层边坡沿着软弱面形成贯通滑面，当输入波幅值达到4 g后，边坡完全破坏；Hilbert谱显示高程对地震波能量有放大作用，且会放大Hilbert能量的强度和频率；顺层边坡变形破坏主要受软弱面控制，表现为上部拉裂和下部剪切，研究结果对顺层边坡地震作用下抗震设计具有一定指导意义。

Abstract: To investigate the dynamic response of a bedding slope under seismic action, a bedding slope model with a slope angle of 45˚ and a strata dip angle of 30˚ was designed and fabricated. Numerical simulations were carried out to analyze the dynamic response law and HHT characteristics of the slope, and to study the instability mechanism and failure process of the slope. The test results show that under seismic action, the slope exhibits an obvious “elevation effect” and “surface-proximity effect”, that is, the acceleration amplification factor of the slope body tends to increase with the increase in elevation and horizontal distance. The weak plane is the weak point in the bedding slope, and the upper part of the weak plane fails first. As the amplitude increases, a continuous sliding surface is formed along the weak plane of the bedding slope. When the amplitude of the input wave reaches 4 g, the slope is completely destroyed. The Hilbert spectrum shows that the elevation has an amplifying effect on the seismic wave energy and will amplify the intensity and frequency of the energy. The deformation and failure of the bedding rock slope are mainly controlled by the weak plane, manifested as upper tensile cracking and lower shearing. The research results have certain guiding significance for the seismic design of bedding slopes under dynamic action.