金沙江虎跳峡河段上江坝址若干关键工程地质问题研究

上江坝址是虎跳峡高坝替代方案的比选坝址，是虎跳峡河段重点研究的开发方案之一，该坝址区域构造背景复杂、河床覆盖层深厚、两岸坝肩发育特大型滑坡等，工程地质问题突出。基于野外大量的工程地质勘察工作，表明：工程区域断裂构造发育，地震活动较频繁，但坝址避开了区域主干断裂和活动断层，位于地质构造相对稳定的地块，适宜建坝；在深厚的河床覆盖层上建高土石坝存在的关键技术问题为沉降变形和防渗处理问题，筑坝技术达到世界先进水平；左右坝肩分布的滑坡整体稳定性较好，对大坝存在的影响主要为沉降变形、渗漏、高边坡稳定性等，筑坝技术难度较大。结果为上江坝址筑坝技术研究和本河段水电开发方案坝址选择提供依据，对类似水电工程地质研究具有较好的参考意义。

Study on Some Key Engineering Geological Problems of Shangjiang Dam Site on Tiger Leaping Gorge Reach of Jinsha River

The Shangjiang dam site, located on Tiger Leaping reach, is an important plan for study, and also an alternative plan to the high dam one. The engineering geological problems are obvious, such as complicated areal structure background, thick overburden in river bed, occurring of large-scale landslides on both dam abutments, and so on. By an abundance of geological investigation work on site, we conclude that: (1)the faults are developed, the earthquakes are active, but the dam site is far away from the major fault and the active earthquake and on a relatively stable area suitable for the construction; (2)the key problems are the controlling of the settlement deformation, the seepage-proofing and the construction level; (3)the stability of the landslides distributed on both dam abutments is fine, and the major problems for the dam are only the settlement deformation, leakage, stability for high slopes, and so on, which will be a challenge for the construction. The study result may be useful for the work of Shangjiang Dam, the site selecting in the development plan on this reach, and the geology study for other similar projects.