考虑土体冲刷应力历史的单桩承载性状分析

目前分析冲刷对桥梁桩基承载力的影响通常采用将冲刷土体直接移除的方法,近似认为冲刷使得桩基埋深减少,桩头出露高度增加。这种方法忽略了冲刷后土体应力历史变化对桩基承载性能的影响。笔者提出了一种能够考虑土体应力历史的简化方法,该方法适用于ABAQUS内置的Mohr-Coulomb模型,应用ABAQUS软件对竖向受荷单桩进行了数值模拟,与模型试验结果的对比,验证了该方法的可行性。通过参数分析,进一步考察了冲刷深度对桩基竖向承载力的影响。研究表明,冲刷将极大地降低摩擦桩的竖向承载能力,其极限承载力损失量随冲刷深度的增加呈线性增加趋势。因此,实际工程中必须重视冲刷对摩擦型桩基竖向承载力的影响。

Numerical Simulation of Bearing Behaviors of Single Pile under Scouring Conditions Considering Soil Stress History

A common way to analyze the vertical bearing behaviors of bridge scoured piles is to remove the scoured soil while just considering decrease of embedded depth and increase of exposing height.This approach ignores the fact that the remaining soil experiences different stress histories before and after scouring,which can be expected to affect vertical bearing behavior of piles.In this paper,a simplified method applicable to numerical analysis with ABAQUS which can consider stress history of soil after scouring is proposed and verified by comparing results of numerical calculation and model tests.Moreover,the influence of scouring depths on vertical bearing behavior of piles is investigated by numerical analysis.The results show that scour results in significant reduce of vertical bearing capacity of friction piles.The vertical bearing capacity decreases with increase of scouring depth linearly.Thus great attention should be paid to the effect of scouring on vertical bearing capacity of friction piles in engineering practice.