基-填界面开挖台阶对顺坡填筑高边坡稳定性影响研究

高填方边坡在山区机场和水利工程建设中大量存在，在基岩和填土界面处开挖台阶可以提高边坡安全性。通过Bishop方法和有限元方法，分别研究了在基-填界面上开挖台阶对提高无限长和有限长高填方边坡稳定性的贡献和机理。并以某西南山区高填方工程为例，分析考虑暴雨、地震情况下，开挖台阶对边坡稳定性的影响。开挖台阶是否能显著提高边坡稳定性需考虑台阶形状和基-填界面的相对强度（界面折减系数）的影响。当基岩强度较高且界面折减系数较小时，台阶开挖有利于提高稳定性；反之，界面折减系数越接近于1，台阶的作用越微弱。台阶位于坡脚时有利于增加边坡稳定性。暴雨与地震会使滑裂面加深，开挖台阶对稳定性影响趋势不变。

STUDY ON STABILITY INFLUENCE OF HIGH SLOPE FOUNDATION-FILL INTERFACIAL EXCAVATION STEPS

High filling slopes are widely used in airports and water conservancy projects in mountainous areas. Excavating steps at the interface of bedrock and soil filling can improve slope stability. Using Bishop's and finite element methods, the contribution of excavation steps on foundation-filling interfaces to improve the stability of a high fill slope is studied. Taking a high filling project in a southwest mountainous area as an example, the influence of excavation steps on slope stability is analyzed with the consideration of a heavy rain and an earthquake situation. Step excavation cannot significantly improve slope stability. The shape of steps and the relative strength of foundation-filling interfaces should be considered. When the strength of bedrock is high and the interfacial folding coefficient is small, step excavation is beneficial to improve stability. The higher the relative strength is, the smaller the effect of steps is. On the contrary, the closer the interface reduction coefficient is to 1, the weaker the step effect is. When the steps are located at the foot of a slope, it is beneficial to increase the stability of the slope. The influence of excavation steps on stability is unaltered.