桩及桩板墙加固路基边坡的对比室内模型试验研究

COMPARATIVE MODEL TEST ON SUBGRADE SLOPE REINFORCED WITH PILE AND SHEET-PILE WALL

设计了尺寸相似比为1︰25的室内试验模型,对两组不同支护方式下预设滑面的边坡模型进行逐级水平推移式加载,对比分析了在横向荷载作用下抗滑桩及桩板式挡墙(后置式挡土板)两种支护结构的受力及变形特点(考虑深层滑坡)。研究发现:边坡-支护结构系统的破坏明显分为3个阶段,即滑体土压密阶段、支护结构主要变形阶段及支护结构失效阶段;距桩顶14cm的同一水平位置桩后土压力传递效率较低,与距加载板位置远近成反比,呈指数变化规律;抗滑桩仍是两种支护结构的主要受力构件,挡土板延长了模型破坏的主要变形阶段,加固效果显著;桩板支护结构较抗滑桩支护多承受一级荷载(0.5k N),承载力提高了14.29%;挡土板优化了桩后土压力的分布形式,使作用在整个桩背侧土压力合力的作用点更靠近锚固端,有利于抵抗桩身的挠曲变形。本研究可为这两种边坡支护结构形式的选择提供参考。

An indoor slope model is designed and constructed for experimental test. A sliding surface is pre-installed in the slope model. The slope is reinforced with pile and sheet pile wall respectively. The geometry dimensional similarity ratio of the indoor slope model to the actual slope size is 1^25. The model is horizontally loaded step by step. Comparative analysis on the force and deformation characteristics of the two different supporting structures under horizontal load is conducted. The results show that the failure process of the slope-support structure system is divided into three stages. They are the sliding soil compaction stage, the main deformation stage ofsupporting structure, and the failure stage of supporting structure stage respectively. Transfer efficiency of soil pressure behind the piles is relatively low at the same horizontal position of pile 14c m below the pile top, which is inversely proportional to the position of the loading plate and in exponential variation law. Anti-slide pile is the main bearing component of the two supporting structures, and the retaining plank extends the main deformation stage of model damage. The reinforcement effect is obvious. Compared with the anti-slide pile supporting structure, the ultimate load of pile supporting structure is 0. 5k N more than that of anti-slide pile, and the bearing capacity of pile supporting structure increases by 14. 29%. Distribution form of soil pressure behind the piles is optimized by adopting retaining plank, which makes the soil pressure closer to the end of the anchor and is propitious to resist the flexure deformation of the pile body. This research can provide references for selecting the two different slope supporting structures.