考虑坝体-地基接触效应的特高心墙堆石坝结构安全性研究

Study on safety of a high earth-core rockfill dam considering contact effect between dam and foundation

传统的土石坝结构计算分析中通常忽略坝体与基岩之间的摩擦滑动变形,这与实际情况不符,坝体地基接触摩擦效应对于修建在狭窄陡峻河谷区的特高坝表现尤为明显。采用三维有限元方法对修建在狭窄河谷区特高心墙堆石坝结构安全性进行了研究,研究中考虑了坝体地基摩擦接触效应,模拟了水库蓄水、坝料湿化、流变等多因素共同作用下坝体结构力学行为以及坝体地基接触位移演化过程。基于倾度法对坝体运行过程中可能的裂缝扩展区域进行了预测。研究得出:对于狭窄河谷上特高土石坝,坝体与地基的相对滑移较大,计算中应予以考虑。研究结论可为峡谷区特高心墙堆石坝设计提供技术依据。

With a traditional method to calculate the stress and deformation of earth-rock dam,the contact effect between the dam and the bedrock is neglected,which is not consistent with the actual condition.The contact friction has a significant effect on the high dams located in the narrow and steep valleys.In this research,a high earth-core rockfill dam to be built in a narrow valley area is studied,the friction contact effect between the dam and the bedrock,water storage,wetting and rheology effect are all considered to simulate the dam body behaviors.Based on the deformation gradient method,the area where cracks may occur during the operation of the dam is predicted.Calculation results are used to evaluate the safety of the earth-core rockfill dam.It is found that the relative slip displacement between dam body and foundation is large for high earth-rock dams in narrow river valleies and should be considered.The conclusion of the study can provide technical basis for the design and construction of high earth-core rockfill dams located in canyon areas.