三峡库区黑石板滑坡的变形特征和涌浪预测

The deformation characteristics and surge wave prediction of the Heishiban landslide in the Three Gorges Reservoir area

三峡库区水位波动易于导致库岸滑坡失稳进而形成涌浪灾害。以三峡库区黑石板滑坡为研究对象,基于近5年的监测数据分析:三峡库区黑石板滑坡为动水压力型滑坡,降雨只在库水位下降时和低水位波动期对滑坡的变形有一定的助推作用,其他时间对滑坡变形影响并不大。通过分析累积位移曲线中的6次阶跃变形,确定了库水位下降至165 m时为滑坡阶跃变形的启动阈值,并以此作为滑坡最危险情况下所对应的库水位高度,将其设置为数值模拟的初始水位高度。运用FLOW-3D软件进行了涌浪计算及预测:在165 m水位时,滑坡入水的最大速度为19.4 m/s,涌浪产生的最大波高为24.9 m,最大爬高为42.21 m。预测结果表明,黑石板滑坡破坏后引发的涌浪将会淹没水田坝乡沿岸部分区域,毁坏入乡主干道,这将严重影响后续对水田坝乡的救援工作。该研究为三峡库区库岸滑坡涌浪的风险管理提供科学依据,具有一定的工程实践意义。

The fluctuation of water levels in the Three Gorges Reservoir can cause instability in reservoir banks,resulting in the formation of landslides and surging wave disasters.In this paper,the Heishiban landslide in the Three Gorges Reservoir area is selected as the research object based on the analysis of monitoring data spanning over a decade,which is observed as a hydrodynamic pressure-triggered landslide.Rainfall has a certain boosting effect on the deformation of the landslide only during the periods of reservoir water level decline and low water level fluctuations,while it has little impact on the landslide deformation at other times.By analyzing the six-step deformation in the cumulative displacement curve,the threshold for triggering landslide step deformation was determined when the reservoir water level drops to 165 m.This level was set as the initial water level height for numerical simulation,corresponding to the most dangerous situation of the landslide.Surge wave calculation and prediction were conducted using FLOW-3D software.At a water level of 165 m,the maximum velocity of landslide entry into the water was 19.4 m/s,the maximum wave height generated by the surge wave was 24.9 m,and the maximum run-up reached 42.21 m.According to the prediction results,the surge waves generated after the destruction of the Heishiban landslide will inundate parts of the areas of Shuitianba town and destroy the main roads into the town,significantly affecting rescue efforts in Shuitianba town.This study provides a scientific basis for the risk management of reservoir bank landslide surge waves in the Three Gorges Reservoir area and has certain engineering practical significance.