水库枢纽区抬升变形水文地质结构模式研究

水库蓄水引起枢纽区产生抬升变形的现象在国内外水利工程中比较少见。为了解岩体水文地质结构对抬升变形的影响,通过对国内外文献研究,提出了坝基及近坝库岸边坡产生抬升变形的水文地质结构模式:即坝址区存在倾向下游或两岸的相对隔水层,且相对隔水层下存在透水性较大的水文地质结构层。采用流固耦合数值分析方法研究了相对隔水层产状要素变化对抬升变形空间分布规律的影响。研究结果表明:相对隔水层在上游库区的出露区域至坝体距离越近,下游岸坡抬升变形范围越大,抬升变形量也越大;随着相对隔水层倾向下游倾角的增大,枢纽区最大抬升位移呈先增大后减小的变化规律;隔水层倾向角的变化将引起抬升变形空间分布位置的变化。

Modes of hydro-geological structure for uplift deformation near reservoir pivot

The uplift deformation phenomenon occurring in the dam due to reservoir impounding appears rarely. To explore the influences of the hydro-geological structure of the rock mass on the uplift deformation, the mode of the hydro-geological structure inducing the generation of uplift deformation near the dam area is put forward through the researches on the existing literatures. The relative impermeable layer inclination to the downstream under the dam foundation and the relative permeable layer lying beneath the impermeable layer are the necessary hydro-geological conditions for the generation of uplift deformation. A numerical method based on the hydro-mechanical coupling theory is employed to study the influences of the variation of attitude elements on the spatial distribution law of uplift deformation occurring near the dam. It is shown that the shorter the distance between the exposure site and the dam, the greater the uplift deformation value. With the increase of the dip angle of the impermeable layer, the maximum uplift deformation near the dam increases firstly and then decreases. It is also indicated that the spatial distribution position of the uplift deformation is directly determined by the variation of dip direction.