基于细观水土动力流固耦合的高聚物防渗墙与坝体相互作用研究

Polymer anti-seepage wall is a new technology for the reinforcement of dikes and dams. The technology has advantages of efficient, ultrathin, minimally invasive and economic properties, which has the prodigious value of popularization and application. Combined with seismic safety problems of earth-rock dams in reinforcement projects, aiming at the coordination mechanism of new anti-seepage wall and earth-rock dam in seismic area, the study on the interaction of polymer anti-seepage wall and earth-rock dam based on dynamic coupling of micro-scale soil skeleton and pore water has been planned to be researched. Dynamic mechanical thermal analysis is planned to be used in studying dynamic viscous-elastic mechanical properties of polymer materials and viscous-elastic constitutive model is established. Based on dynamic coupling of micro-scale soil skeleton and pore water, combined with viscous-elastic constitutive model of polymer materials, numerical model of earth-rock dam with polymer anti-seepage wall is established. The model is validated by previous dynamic centrifuge test results and used for seismic response analysis. Then the dynamic interaction of polymer anti-seepage wall and earth-rock dam is studied. Based on systematic study on the law of the interaction of polymer anti-seepage wall and earth-rock dam, the bearing capacity of anti-seepage wall and slope stability of the dam under different engineering condition are discussed. The expected achievements will offer scientific basis and fundamental basis for earth-rock dams with polymer anti-seepage walls under earthquake.

高聚物防渗墙是堤坝除险加固新技术，具有高效、超薄、微创、经济等优点，有广阔的推广应用前景。项目结合中小型水库除险加固工程抗震安全，对新型防渗技术在震区应用的墙-坝协调复杂机制问题，开展基于细观水土动力流固耦合的高聚物防渗墙与坝体相互作用研究。拟通过动态力学热分析试验研究高聚物材料动态黏弹性力学性能，建立高聚物黏弹性本构模型；基于细观尺度的坝内水土动力流固耦合，结合高聚物黏弹性本构模型，建立反映防渗墙工程特性及受力特点的土石坝动力流固耦合数值计算模型；基于前期动力离心试验结果对所建模型进行标定，并对地震响应进行分析，在系统研究防渗墙与土石坝动力相互作用规律基础上，探讨不同工程条件下防渗墙的承载性能及坝坡稳定性。预期成果可为提高地震作用下加固工程中高聚物防渗墙土石坝的安全性、可靠性提供理论基础和科学依据。

高聚物防渗墙作为一种新型防渗加固技术，具有造价低、施工快、环境友好等优点，已逐步应用于土石坝除险加固工程中。我国有大量土石坝位于震区，在地震作用下，土骨架和孔隙水会发生细观流固耦合作用，易引发坝坡动力失稳及防渗墙动水劈裂等一系列安全问题，且新型高聚物注浆材料在与土体黏结时的“根须状”接触状态亦使得墙-坝相互作用在大坝地震安全性评价中不容忽视。基于此，本项目系统性开展了基于细观水土动力流固耦合的高聚物防渗墙与坝体相互作用研究：进行了高聚物注浆材料热机械力学分析试验（DMA），研究了高聚物注浆材料的动态黏弹特性，并提出了基于广义Maxwell的动态黏弹性本构模型；从Biot动力固结理论出发，基于完全非线性法，联合高聚物防渗墙土石坝定解条件、动力边界条件与高聚物材料动态黏弹性本构模型，建立了高聚物防渗墙土石坝细观动力流固耦合模型，研究了不同水位、防渗墙密度及厚度下的高聚物防渗墙土石坝的地震响应特征及规律；自主设计了高聚物-土接触面试验模具，并采用SRS-150动环剪仪开展了高聚物-土接触面静动力环剪试验，探讨了高聚物-土接触面静动力特性及其影响因素，研究了粘结状态、高聚物密度、竖向应力和土质类别对高聚物-土接触面静力特性的影响规律，明晰了高聚物密度、剪切幅值以及竖向应力对高聚物-土接触面动力特性的影响规律；联合高聚物-土接触面特性，基于高聚物防渗墙土石坝细观动力流固耦合建立了地震作用下高聚物防渗墙土石坝相互作用模型，研究了地震作用下高聚物防渗墙和邻近土体的加速度以及位移协调性变化规律，探讨了防渗体类型、地震加速度以及高聚物密度对墙坝地震响应协调性影响规律，分析了高聚物防渗墙-土石坝结构体系模态，探讨了高聚物防渗墙土石坝的地震响应特征及地震稳定性。