广东沿海软基堤坝破坏机制及工程对策

广东沿海堤坝较多位于软基上,其破坏特征与软土变形有关。据此,系统分析软基上海堤失稳原因和破坏机制;同时,阐述在软基上修筑堤坝并提高其防御能力可从提高地基承载力、消减波浪能量、优化断面型式及采用轻质堤坝等多方面考虑。基于优化设计理论和堤基堤身整体分析模型,通过一个简单算例计算上下游坡比、填筑材料自重和地基加固区域等对软基上海堤稳定性的影响。优化分析结果表明,采用下游较上游缓的坡比对堤坝的整体稳定有利,且采用轻质材料填筑堤坝能有效克服软基的诸多不利因素;另外,软基加固更应针对堤下浅层地基。

FAILURE MECHANISM AND ENGINEERING COUNTERMEASURE OF COASTAL LEVEE ON SOFT SOIL FOUNDATION OF GUANGDONG PROVINCE

More coastal levees are located on soft soil foundation in Guangdong Province,and the failure mechanism is related to the deformation of soft soil.The failure reason and mechanism of dikes on soft soil foundation are analyzed.In order to improve the stability of levee,the measures,such as improving foundation bearing capacity,removing wave energy,optimizing section pattern,adopting lightweight fill material,are effective for constructing dike on soft soil foundation.Based on optimized design theory and integration analytical model of levee structure and its foundation,a case study of the influence of design factors on levee stability is analyzedi,ncluding the slopes of upstream and downstream,material self-weight of pave dike,zone of foundation improvement.The optimized results show,using the section where downstream is slower than upstream is avail for overall stability of dike,and that using lightweight fill material can overcome some disadvantages of soft basement.In addition,soft soil treatment should be focused on shallow foundation under levee.