马世茂,于怀昌,孙统领,张俊然,王闯,王子睿

• 1:中国南水北调集团中线有限公司渠首分公司
• 2:华北水利水电大学

摘要(Abstract)：

非饱和膨胀土的径向劈裂强度与裂隙扩展之间存在密切联系，分析不同含水率下非饱和膨胀土的裂隙演化机制，对南水北调中线工程膨胀土渠段的工程灾害防治具有重要的理论意义和工程实用价值。联合运用WP4C仪、压力板和PIV(Particle image velocimetry, PIV)劈裂试验系统，对南水北调中线工程邓州段某高填方渠堤非饱和膨胀土进行了一系列的持水特性试验和劈裂试验，结合持水特征曲线，揭示了不同含水率膨胀土的劈裂强度、裂隙演化过程、位移矢量场的变化规律及其内在机理。试验表明：(1)膨胀土的含水率和饱和度均随吸力的增大而减小。在低吸力范围内膨胀土试样含水率和饱和度随吸力的增加而减小趋势缓慢；在高吸力范围内，含水率和饱和度与吸力基本呈线性关系，随吸力的增加，试样的含水率和饱和度显著减小。(2)含水率对膨胀土的劈裂强度具有显著影响。随含水率的增加，试样的劈裂峰值荷载呈先增加后减小的变化规律，劈裂峰值荷载在含水率为3%～12%范围内持续增加，而在12%～24%范围内持续减小；上述试验现象与不同含水率膨胀土试样具有不同的颗粒间液桥作用有密切的内在联系。(3)不同含水率下膨胀土劈裂试验荷载-位移曲线均可分为荷载接触阶段、荷载线性增加阶段、张拉破坏阶段和残余阶段。膨胀土劈裂试验不同阶段的裂隙、位移矢量场的变化规律与荷载-位移曲线变化之间存在着一一对应关系。

关键词(KeyWords)： PIV技术;膨胀土;劈裂;含水率;持水特性;位移矢量场

Abstract:

Keywords:

基金项目(Foundation):

作者(Author): 马世茂,于怀昌,孙统领,张俊然,王闯,王子睿

DOI: 10.13928/j.cnki.wrahe.2024.S1.059

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