荆江河段崩岸机理及多尺度模拟方法

发布时间：2018-09-15 19:55

【摘要】：三峡工程运用后,进入荆江河段的水沙条件大幅度改变,导致近期崩岸频繁发生,影响局部河段的河势稳定及河道防洪安全。荆江段河岸组成一般为上层黏性土、下层沙土的二元结构,在近岸水流冲刷及河道水位涨落过程中受多种因素作用而发生崩塌。以往崩岸模拟考虑因素少,且相关参数难以量化确定。将河流动力学与土力学结合,提出了荆江段河岸土体物理特性与抗剪、抗冲及抗拉强度三大力学特性的量化指标,建立了上、下荆江二元结构河岸稳定性的计算方法,揭示了坡脚冲刷、潜水位变化等因素对岸坡稳定性的影响;提出了河岸崩退过程的多尺度模拟方法,将崩岸力学模型与水沙数学模型耦合,不仅能模拟河道内水沙输移及床面冲淤过程,而且还能模拟不同二元结构河岸的崩退过程。将建立的模型应用于荆江河段典型断面、长河段及局部河段的崩岸过程模拟,计算结果与实测值总体符合较好。提出的多尺度模拟方法为荆江崩岸预测提供了理论与技术基础。
[Abstract]:After the operation of the three Gorges Project, the conditions of water and sediment entering the Jingjiang reach changed greatly, which resulted in frequent bank collapse in the near future, which affected the stability of the river regime and the flood control safety of the local reach. The river bank of Jingjiang section is generally composed of upper clay soil and the dualistic structure of lower sandy soil, which collapses in the process of inshore water scouring and river water level fluctuation by many factors. In the past, few factors were considered in the bank collapse simulation, and the related parameters were difficult to determine quantitatively. Based on the combination of river dynamics and soil mechanics, the quantitative indexes of soil physical properties and shear, impact and tensile strength of riverbank in Jingjiang reach are put forward, and the calculation method of riverbank stability of upper and lower Jingjiang binary structure is established. The effects of slope foot scour and diving level change on slope stability are revealed, and a multi-scale simulation method is proposed to simulate the collapse process of riverbank, which is coupled with the mathematical model of water and sediment. It can not only simulate the process of water and sediment transport and bed surface scouring and deposition, but also simulate the collapse process of different binary structure riverbanks. The model is applied to simulate the bank collapse process of typical section, long river and local reach of Jingjiang River, and the calculated results are in good agreement with the measured values. The multi-scale simulation method provides a theoretical and technical basis for the prediction of Jingjiang river bank collapse.
【作者单位】：武汉大学水资源与水电工程科学国家重点实验室;
【基金】：国家重点研发计划课题(2016YFC0402303) 国家自然科学基金资助项目(51579186) 三峡后续规划研究课题三(CKSG2016874/HL)
【分类号】：TV85

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