北坑水库大坝坝型比选及坝基处理方案研究

Study on dam type comparison and dam foundation treatment scheme of Beikeng Reservoir Dam

摘要

北坑水库坝址为不对称宽谷地形，岩性为凝灰岩，岩石较坚硬，左岸覆盖层较为深厚。与重力坝相比，当地材料坝对地形地质条件适应性强，料源条件更好，且投资更省；考虑风化料心墙堆石坝施工工期较长，且与紧邻布置的溢洪道有一定干扰，推荐坝型为面板堆石坝。针对坝基深厚覆盖层问题，考虑“保留部分覆盖层+振冲碎石桩”方案大坝面板变形开裂风险相对较大，施工难度大，施工工期长，工程投资多，因此大坝坝基采用“全部挖除覆盖层”的处理方案。

Abstract

The dam site of Beikeng Reservoir is asymmetric wide valley terrain, the lithology is tuff, the rock is hard, and the overburden on the left bank is relatively deep. Compared with the gravity dam, the local material dam has strong adaptability to topographic and geological conditions, better material source conditions and less investment. Considering that the construction period of the weathered material core wall rockfill dam is long, and it has certain interference with the adjacent spillway, the recommended dam type is the face rockfill dam. Aiming at the problem of deep overburden layer of dam foundation, considering the scheme of ‘retaining part of the overburden layer + vibroflotation gravel pile', the risk of deformation and cracking of the dam panel is relatively large, the construction is difficult, the construction period is long, and the project investment is large. Therefore, the dam foundation adopts the treatment scheme of ‘all excavation of the overburden layer'.

关键词

坝型比选 / 面板堆石坝 / 风化料心墙堆石坝 / 振冲碎石桩 / 挖除覆盖层

Key words

dam type selection / face rockfill dam / weathered material core wall rockfill dam / vibroflotation gravel pile / excavate the covering layer