基于H-KS模型的层状深厚覆盖层流变对面板堆石坝结构性能的影响

深厚覆盖层中各层岩土体的流变对大坝及渗控体系有一定的影响,需要深入剖析。本文探索了新的流变元件模型H-KS以模拟层状覆盖层,借助Comsol建立流变与流固耦合模型,按时间顺序计算了河口村面板坝各阶段的力学指标,分析了坝基流变对大坝及防渗体系的影响。结果表明,对于各向异性明显的层状坝基,采用H-KS流变模型能较好反应大坝各阶段的应力、变形和渗流实际情况,误差均在5%以内；计算结果相比不考虑流变的Duncan E-B模型,应力和变形均增大11.8%以上,部分增量对大坝结构的安全稳定造成影响；填筑期的沉降和应力总量占比达70%以上,但单位时间增量却较小,如沉降增量仅为0.015m/月；蓄水期的岩土体流变及流固耦合作用对大坝各部位强度和刚度影响最大,应力及沉降单位时间增长率分别为0.02mpa/月、0.038m/月；运行期的各指标增长率逐渐趋缓,最终趋于稳定,但变形和应力增量可能会导致主要结构失稳或破坏。混凝土面板-趾板-防渗墙是完整有效的渗流控制体系,坝基流变导致防渗墙上部水平位移增大,整体强度降低；趾板和面板在中部有受弯破坏的趋势。层状岩土体流变是具有时效性的,该层状坝基的流变在蓄水后2~3年间基本完成,相应指标也趋于稳定。研究结果对层状覆盖层上的面板坝安全稳定体系的建立提供了理论支持。

Influence of rheology of layered deep overburden layer on structural performance of concrete faced rockfill dam based on H-KS model

The rheology of each layer of rock and soil in the deep overburden has a certain impact on the dam and seepage control system, which requires in-depth analysis. This paper explores a new rheological element model H-KS to simulate the layered overburden, establishes a rheological and fluid-solid coupling model with the help of Comsol, calculates the mechanical indicators of each stage of the Hekou Village concrete face dam in chronological order, and analyzes the rheology of the dam foundation Impact on dams and anti-seepage systems. The results show that for the layered dam foundation with obvious anisotropy, the H-KS rheological model can better reflect the actual stress, deformation and seepage conditions of the dam at each stage, and the error is within 5%; Compared with the Duncan E-B model that does not consider rheology, the calculation result is that the stress and deformation are both increased by more than 11.8%, and some of the increase will affect the safety and stability of the dam structure; the total settlement and stress during the filling period account for more than 70%, but the unit time increases However, the amount is small, such as the settlement increment is only 0.015m/month; the rheology and fluid-solid coupling of the dam rock and soil during the impoundment period have the greatest impact on the strength and stiffness of each part of the dam, and the stress and settlement unit time growth rates are respectively It is 0.02mpa/month, 0.038m/month; the growth rate of each index during the operation period gradually slows down and eventually stabilizes, but the deformation and stress increase may cause the main structure to instability or damage. Concrete panel-plinth-impervious wall is a complete and effective seepage control system. The rheology of the dam foundation increases the horizontal displacement of the upper part of the impervious wall and reduces the overall strength; the plinth and the panel tend to be damaged by bending in the middle. The rheology of layered rock and soil is time-sensitive. The rheology of the layered dam foundation is basically completed within 2 to 3 years after water storage, and the corresponding indicators also tend to be stable. The research results provide theoretical support for the establishment of the safety and stability system of the face dam on the layered overburden.