库水位等速下降中均质库岸塌岸现象试验研究

Experiment Study on Homogeneous Bank Caving of Reservoir with Water Level Evenly Lowering

为研究库水位等速下降过程中均质水库岸坡的塌岸现象及岸坡内浸润线的变化特点,以取自三峡库区的含黏粒粉砂为主要试验土料,对建立的4个不同结构的均质岸坡模型进行了7种不同速率的水位下降试验。试验结果表明,库水位下降速率越大,均质水库岸坡的塌岸现象越易发生,但库水位下降速率的大小并不与塌岸现象的严重程度成正相关关系;试验测得浸润线与理论计算结果的比较分析表明,当水位下降速率较小时,浸润线的理论计算结果与试验结果基本一致,但是当水位下降速率较大时,理论计算结果可能会低估浸润线的位置。

In order to investigate the homogeneous bank fall of reservoir and the changing features of the phreatic line when the water level of reservoir is evenly lowering,four homogeneous bank models with different structures are built with the sand containing little clay excavated from Three Gorges Reservoir Area of China,and seven tests with different water level lowering rates are done for each model respectively.The testing results of model indicate that the larger the water level lowering velocity,the more possible the bank falling.But the positive correlation between the severity of the bank caving and the water level lowering velocity isn＇t always right.The typical phreatic lines in the model slope obtained from the experiment are compared with those obtained from a published analytic solution.The comparison indicates that the published analytic solution may be reasonable while the water level lowering velocity is small,but it may undervalue the location of the phreatic line while the water level lowering velocity is large.