鲸鱼沟黄土水库塌岸、淤积调查与预测分析

Investigation and prediction analysis of bank collapse and siltation in whale ditch loess reservoir

为了预测黄土水库改造再利用后的塌岸量与淤积量,对鲸鱼沟现有水库的塌岸和淤积情况进行了地质调查,并据调查结果提出了黄土库区塌岸与淤积预测方法。研究结果表明:现有水库两岸只出现了几处小型滑塌且已基本稳定,统计出黄土岸坡水下磨蚀角在14°~26°之间,残坡积层岸坡水上磨蚀角在20°~31°之间,黄土的水上坡脚坡度为70°左右;库区淤积物横断面十分平坦,淤积主要考虑来自塌岸物质,揭露了现有水库淤积模式,计算得到其淤积厚度为10.3~12.6 m和淤积量为193.5×10^(4)m^(3);结合现有塌岸调查结果,提出了水库塌岸预测原则,采用卡丘金法与岸坡结构法相结合的方法预测了拟建水库的总塌岸量为567×10^(4)m^(3)和入库量为230×10^(4)m^(3);结合现有淤积调查结果,提出了淤积预测方法,即将塌岸量分段淤积于水库底部,预测了拟建水库的淤积厚度为0~22 m之间,大部分地段为10~20 m,淤积量为562.8×10^(4)m^(3),约占总库容的15.2%。本文预测结果为鲸鱼沟黄土水库改造工程提供可行性资料,也为相关黄土水库建设提供参考作用。

In order to predict the amount of bank collapse and deposition after the reconstruction and reuse of the loess reservoir,the bank collapse and deposition of the existing reservoirs in the whale ditch were investigated,and the prediction method of bank collapse and deposition in the loess reservoir was proposed according to the survey results.The results show that there are only a few small landslides on both sides of the existing reservoir and they are basically stable.The underwater erosion angle of the loess bank slope is between 14°and 26°,the water erosion angle of the residual slope is between 20°and 31°,and the slope gradient of the loess is about 70°.The cross section of sediment in the reservoir area is very flat,and the deposition is mainly considered from bank collapse.The existing reservoir deposition model is revealed,and the deposition thickness is 10.3~12.6 m and the deposition amount is 193.5×10^(4)m^(3).Combined with the existing investigation results of bank collapse,the prediction principle of reservoir bank collapse is put forward,and the total bank collapse of the proposed reservoir is predicted to be 567×10^(4)m^(3)and the inflow is 230×10^(4)m^(3)by using the combination method of Kachujin method and bank slope structure method.Combined with the existing sedimentation survey results,a sedimentation prediction method is proposed,that is,the bank collapse is sub-deposited at the bottom of the reservoir,and the sedimentation thickness of the proposed reservoir is predicted to be 0~22 m,most of the sections are 10~20 m,and the sedimentation volume is 562.8×10^(4)m^(3),accounting for about 15.2%of the total storage capacity.The prediction results of this paper provide feasible data for the reconstruction project of Whale Ditch Reservoir in Hanjiang-to-Weihe River valley Water Diversion Project,and also provide reference for the construction of related loess reservoirs.