路堤下高强度桩复合地基失稳破坏模式判别方法

A Failure Mode Identification Method for High-strength Pile-reinforced Composition Foundation Under Embankment Loading

明确桩体复合地基破坏模式是合理评估路堤地基稳定性的基础和关键。针对路堤下高强度桩复合地基破坏模式影响因素较多且破坏模式判别方法缺失的问题,根据地基条件、桩身材料抗弯能力、滑面下锚固深度等因素对复合地基稳定性影响机制,实现高强度桩复合地基桩端滑移破坏、桩体倾斜破坏和桩体弯折破坏三种典型破坏模式的划分;基于滑动面上桩身材料抗弯能力与滑动面下桩前土体抗滑力矩间的大小关系,建立路堤下高强度桩复合地基桩端滑移、桩体倾斜和桩体弯折破坏模式的判别准则和控制条件;通过典型工程案例验证了建立的高强度桩复合地基破坏模式判别方法的合理性,可为路堤下高强度桩复合地基稳定设计提供依据。

A reasonable failure pattern of pile composite ground is a key to correctly evaluate the stability of the embankment.This article is aimed at the problems that the failure mode of high-strength pile-reinforced composition foundation under embankment loading is affected by many factors and the identifying method of failure pattern is missing.According to the influence mechanism of ground conditions,bending resistance capacity of pile materials,anchorage depth under sliding surface on the stability of composite ground,three typical failure patterns of high-strength pile-reinforced composition foundation such as pile tip sliding failure,pile shaft collapse failure and pile shaft bending failure are divided.Based on the relationship between the bending resistance of pile material upper section of sliding surface and the resisting moment of soil in front of the pile below sliding surface,the identifying criteria and control conditions of pile tip sliding failure,pile shaft collapse failure and pile shaft bending failure patterns of high-strength pile composite ground under the embankment are established.The applicability of the proposed method is verified by a typical engineering case.The proposed method can provide a basis for the stability design of the high-strength pile composite ground under the embankment.