降雨作用下路堤边坡的冲刷-渗透耦合分析

SCOURING-PENETRATION COUPLING ANALYSIS OF EMBANKMENT SLOPE UNDER RAINFALL ACTION

为揭示降雨作用下雨水冲刷-渗透过程对非饱和碎石土路堤边坡的作用机制,通过现场资料调查分析,基于坡面冲刷剪切理论推导坡面冲刷深度概化公式,并通过物理模型试验验证该理论推导结果的合理性和适用性,反映坡面上各点的冲刷深度与冲刷时间及所处位置密切相关。模型试验现象真实再现了路堤边坡冲刷-渗透破坏的物理本质,结合试验结果,分析明确了降雨作用下碎石土路堤边坡侵蚀破坏的力学机制。研究结果表明,一定持续时间的强降雨是碎石土路堤边坡失稳的主要诱发因素;雨水冲刷和渗透过程是相互影响且相互促进的,采用物理模型试验方法更好地揭示路堤边坡在冲刷-渗透耦合作用下侵蚀破坏发展过程,可以为类似路堤边坡的稳定性评价及采取工程防治措施提供参考。

In order to reveal the action mechanism of unsaturated debris embankment slope under rainfall action, based on the diagnoses of locale data and theory of scouring shearing stress of slope surface, generalized equation of eroding depth of slope surface is derived. Then, physical model test results are used to verify the rationality and applicability of the theoretical derivation, which reflects that the eroding depths of various points are closely related to scouring time and location on slope surface. Model test actually reproduces physical essence of embankment slopes under scouring-penetrative destruction. Combining with the model test results, mechanism of debris embankment slope caused by rainfall action is analyzed clearly. The research result is shown as follows： Firstly, intensive rainfall with long duration is the main inducing factor of instability and failure of debris embankment slope. Secondly, the scouring and infiltration penetration processes of rainwater influence and facilitate each other. Finally, the destruction development process of embankment slopes by scouring-penetration coupling can be well revealed by adopting physical model test; and the model test can provide the references for stability evaluation and taking protective measures upon similar embankment slopes.