考虑渗流作用的深覆盖层高面板堆石坝流变机理研究

Creep deformation is one of the main cause of long-term deformation of concrete face rockfill dam and failure of the anti-seepage body. This project intends to research the creep mechanism of high face rockfill dam built on deep alluvium foundation considering seepage effect. Large-scale triaxial creep tests considering seepage effect would be conducted to reveal the effect of seepage on the creep mechanism of rockfill and river gravel material. A rockfill-gravel creep model considering the seepage effect would be established on the basis of the test results. Based on the implicit integral iteration method and the Kozeny-Carman model, the unified numerical integration algorithm for the granular material, rigid impervious body, and the interface between them would be studied. Then this project would construct a creep calculation platform for high concrete face rockfill dam built on deep alluvium foundation considering the seepage effect. Based on partial least squares regression and support vector machine algorithm, This project would excavate the nonlinear relationship between long-term deformation and influencing factors , and reveal the long-term creep mechanism of high concrete face rockfill dam built on deep alluvium foundation. Combining with creep test, numerical simulation and data mining results, the creep mechanism of high concrete face rockfill dam built on deep alluvium foundation considering the seepage effect would be revealed, which provides theoretical basis and technical support for the construction of high concrete face rockfill dam on deep alluvium foundation.

流变变形是造成高面板堆石坝长期变形和防渗体失效的主要原因之一。本项目拟以修建在深覆盖层上的高面板堆石坝流变机理为研究主线，考虑渗流对坝体堆石料和地基砂砾石料的作用，开展大型三轴流变试验，揭示渗流作用对堆石料和砂砾石料流变的影响规律，建立考虑渗流作用的坝体-地基流变模型；基于隐式积分迭代方法和Kozeny-Carman模型，研究散粒体、刚性防渗体和两者之间界面的本构数值积分统一算法，开发考虑渗流作用的深覆盖层高面板堆石坝流变计算平台；基于偏最小二乘回归和支持向量机算法，构建深覆盖层高面板堆石坝长期变形与影响因素之间的非线性关系，挖掘深覆盖层高面板堆石坝流变规律；综合分析本项目的试验、数值仿真及数据挖掘结果，揭示渗流作用下深覆盖层高面板堆石坝流变机理，为深覆盖层高面板堆石坝的建设提供理论依据和技术支撑。

以西部地区修建在深覆盖层上的高面板堆石坝为研究对象，开展了渗流-应力耦合作用下深覆盖层高面板堆石坝流变机理研究工作。采用微机伺服粗粒土动静三轴仪，对覆盖层地基砂砾石开展了大型三轴力学特性及流变试验研究。阐明了不同细颗粒含量、材料级配、淤泥含量等因素下材料的力学特性，揭示了复杂条件及不同因素对材料力学特性的影响规律。采用经验本构关系方法和数理统计理论，阐明了E-B本构模型和双曲线模型的适应性。依托苗家坝实际工程，建立了考虑堆石和地基流变及水力耦合效应的覆盖层上面板堆石坝参数反演分析模型，揭示了覆盖层对面板堆石坝力学特性的影响机制。基于实测资料和数值分析对覆盖层上面板堆石坝和基岩上面板堆石坝力学特性差异进行了深入对比分析，揭示了覆盖层上面板堆石坝的应力变形特性及其关键影响因素。建立了包含87个面板堆石坝工程实例实测数据的变形特性数据库。基于多元线性回归理论阐明大坝3个典型变形指标与6个影响因素之间的相互关系，揭示影响面板堆石坝变形的主要因素。采用门限回归理论按照坝高对实例变形数据进行区间聚类划分，在此基础上，构造一种自适应混合核函数，采用粒子群智能优化算法确定支持向量机主要参数，在不同坝高聚类区间内建立改进支持向量机预测模型，挖掘了面板堆石坝长期变形规律。研究成果可以为西部地区深覆盖层高面板堆石坝的建设提供理论依据和技术支撑。本项目发表论文17篇，其中SCI检索11篇，EI检索6篇；申请发明专利8项，授权发明专利1项；登记软件著作权4项；培养硕士生2名；项目成果获得相关协会/学会科技奖2项。