金沙江虎跳峡水电站上江坝址若干关键工程地质问题研究

摘要

The Shangjiang dam site, for Tiger Leaping Hydropower Project is one of the options of the high dam sites. The engineering geological problems of this dam site are very complication, such as compli- cated areal structure background, thick overburden in river bed, occurring of large-scale landslides on both dam abutments, etc. Based on geological investigation some conclusions were attained： （1） the faults are developed, the earthquakes are active, but the dam site is far away from the major fault and located at a relatively stable area, which is suitable for the construction. （2） the key problems for ensuring the safety of the dame are the controlling of settlement deformation, the seepage-proofing and the construction technology. （3） the stability of the landslides on both dam abutments is fine.%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，工程地质问题突出。对大量野外工程地质勘察资料的分析表明：工程区域虽然断裂构造发育，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面临的关键技术问题为沉降变形和防渗处理，需采用尖端的筑坝技术；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。研究结果为上江坝址筑坝技术研究和该河段水电开发方案坝址选择提供了依据，对类似水电工程地质研究具有较好的参考意义。