Abstract: The standard assembly of small or medium span highway girder bridge has short cycle, strong terrain adaptability and remarkable economic effect, which is widely used in mountainous areas of China. However, due to the fixed route, standardized superstructure and the hilly and gully area of mountainous terrain, many bridge piles inevitably stand on precipitous cliffs and other undesirable terrain. On these terrains, the pile-soil interaction is complex and the stability of slope is sensitive. Reasonable distance between pile and slope can ensure the stability of slope and the safety of pile foundation construction. Aiming at the slope stability of precipitous cliff, the nonlinear finite element model was established by ABAQUS, and the strength reduction method was used to analyze the influence of different slope distances on slope stability, soil displacement and pile-soil contact state, taking the distance from pile body to the slope in front of pile as the parameter. The research results show that the high-steep slope belongs to the natural disadvantageous section, the slope safety coefficient is less than 1, and the potential sliding surface is steeper and located at the foot of the slope. With the increase of the distance between adjacent slopes of pile foundation, the overall displacement of the slope and the separation range of the soil in front of the pile in the limit state decrease first and then tend to be constant. Considering the influence of slope distance on the slope stability, displacement and pile-soil contact state, it is suggested that the distance of pile foundation on the top of steep slope should not be less than 10 m.

Key words: bridge engineering, precipitous cliff, pile-soil interaction, distance between pile and slope, slope safety factor, strength reduction

摘要： 标准装配化的中小跨径山区公路梁式桥周期短、地形适应性强、经济效应显著，在我国山区应用广泛，但由于路线的固定、上部结构的装配标准化和山区地形的沟壑纵横，导致诸多桥梁桩址不可避免立于陡崖等不良地形之上，桩-土作用复杂、边坡稳定性问题敏感，合理的桩身临坡距离能够保证边坡稳定性和桩基施工工程中的安全性。针对陡崖坡段边坡稳定性问题，笔者利用ABAQUS建立非线性有限元模型，采用强度折减法以桩身至桩前临坡距离为参数进行了不同临坡距对边坡稳定性、土体位移和桩土接触状态的影响特征分析。研究结果表明：高陡边坡属于天然不利地段，边坡安全系数小于1，潜在滑动面形状较陡且位置在坡脚之上；随着桩基临坡距的增大，极限状态下边坡土体的整体位移和桩前土体的脱开范围先变小后趋于不变，考虑临坡距对边坡稳定性、位移和桩土接触状态的影响，建议陡坡坡顶桩基临坡距离应不小于10 m。

关键词: 桥梁工程, 陡崖, 桩-土作用, 临坡距, 边坡安全系数, 强度折减