地震作用下多级平台路堑边坡的动力响应研究

Study on Dynamic Response of Cutting Slope of Multistage Platform under Earthquake

以小江断裂带为背景,以岩体动力学参数研究为基础,利用FLAC3D软件建立单一均质岩质三维边坡概化模型,从加速度、位移、塑性区等方面研究地震作用下多级平台不同宽度对边坡的动力响应影响。结果表明,地震作用下单一均质岩质边坡的破坏模式是沿某一潜在贯通破裂面失稳;边坡平台临空面对地震波具有放大效应,但随着平台宽度增加地震波放大效应会被削弱;平台设置可减小坡脚剪应力集中,塑性区由坡体内部趋于坡体表面发展,有效提高边坡的整体抗震稳定性,但坡脚处仍易发生剪切破坏,应加强支护。

Based on the study of dynamic parameters of rock mass and the background of Xiaojiang Fault Zone,a threedimensional generalized model of single homogeneous rock slope is established by FLAC3 D software to study the effects of different width of multistage platform on the dynamic response of slope under earthquake from the aspects of acceleration,displacement and plastic zone.The results show that,(a)the failure mode of a single homogeneous rock slope under the action of earthquake is to lose stability along a potential through fracture surface;(b)the free face of slope platform has amplification effect on seismic wave,but the amplification effect will be weakened with the increase of platform width;and(c)the setting of platform can reduce the shear stress concentration at the toe of slope,and the plastic zone tends to develop from the inside to the surface of slope,which effectively improve the integrity of slope,but the shear failure is easy to occur at the foot of slope,so the support should be strengthened.