三峡库区三门洞滑坡潜在涌浪风险研究

三峡库区三门洞滑坡总体积为548万m^3,属大型滑坡,一旦滑移破坏,所产生的涌浪将威胁青干河航运安全。在现场调查及长期监测数据的基础上,对滑坡的变形破坏机理进行了分析;通过工程类比法、质点能量法及公式法得到了滑坡的失稳运动特征,采用基于水波动力理论的FAST数值模拟软件对三门洞滑坡的涌浪风险进行了计算分析。结果表明,滑坡目前处于等速变形阶段,属于欠稳定状态,在降雨或水库周期性蓄水等诱发因素的影响下,滑坡存在大规模滑移的可能性。计算可知,滑坡的最大滑动速度可达4.51m/s,产生的最大涌浪高度为21.0m,对岸最大爬高为25m。此外,借鉴海啸预警划分方法,对滑坡区域进行了危险预警区域的划分。

Potential Surge Risk of Sanmendong Landslide in Three Gorges Reservoir Area

The total volume of the Sanmendong landslide in the Three Gorges reservoir area is 5.48 million m^3, which is a large-scale landslide. Once the landslide is destroyed, the surge will threaten the navigation safety of Qinggan River.Based on the field investigation and long-term monitoring data, the deformation and failure mechanism of the landslide is analyzed. The instability characteristics of the landslide are obtained by the engineering analogy method, the particle energy method and the formula method. Then the FAST software based on the water-wave dynamic theory is adopted to calculate and analyze the impulsive wave risk of the Sanmendong landslide. The results show that the landslide is in the state of constant velocity deformation, which is in an unstable state. With the induced factors such as rainfall or periodic water level rise and fall, the landslide would be likely to large-scale slip. The calculation shows that the maximum sliding speed of the landslide can reach 4.51 m/s, the maximum wave height can reach 21.0 m, and the maximum climb height can reach 25 m. In addition, referring to the early warning division method of tsunami, the dangerous warning area can be obtained.