深大水库高陡土质库岸塌岸预测图解模型研究

Study of Graphical Model for predicting Collapse of High-steep Soil Bank in Deep Reservoir

茨哈峡超高坝的库区土质岸坡,以松散-弱胶结的Q_3砂砾石为主,多呈台阶型近直立状,坡高300 m以上,且部分库段构成水下岸坡的主体。对该类高陡砂砾石库岸进行塌岸预测,目前尚无可借鉴的工程实例,且常用的预测方法大多适用性较差。在塌岸机理研究结论的基础上,从"两段法"塌岸预测图解法的基本思路出发,结合实际地质条件、水库运行方式和"库岸结构法"适用性,对两段法图解模型的预测起始点、水位波动带进行修正,对水上、水下稳定坡角进行选择研究,提出了较适于茨哈峡水库高陡土质岸坡的"三段法"塌岸预测图解模型。

The soil bank slope at the reservoir area of the Cihaxia super-high dam is mainly composed of loose-wet cemented Q 3 sand gravel, which is mostly stepped and nearly vertical, with a slope height of more than 300 m, and some reservoir sections constitute the underwater bank. For the collapse prediction of this kind of high-steep sand gravel bank, no engineering project is available for reference, and the ordinary prediction methods are mostly poorly applicable. On the basis of the conclusion of the research on the mechanism of bank collapse, starting with the basic idea of the "Two-section Method" bank collapse prediction graphic method, combined with the actual geological conditions, the operating mode of the reservoir and the applicability of the "Reservoir Bank Structure Method", the prediction starting point and the water level fluctuation zone of the graphical model of the Two-section Method are corrected, and the selection of the stable slope angle above the water level and underwater is studied, thus proposed the graphical model of the "Three-section Method" collapse prediction applicable for the high-steep soil bank slope of the Cihaxia Reservoir.