江坪河水电站坝址深层风化岩体对坝型选择的影响研究

Influence Analysis of Deep Weathered Rock Mass on Dam Type Selection of Jiangpinghe Hydropower Station

江坪河水电站坝址河谷呈"V"形,宽高比约1. 8,具备修筑高拱坝的地形条件,但坝址两岸尤其是右岸谷坡在进入弱风化下限或微风化岩体后,出现范围较大的深层风化岩体。通过分析深层风化岩体对拱坝和面板堆石坝2种坝型坝基变形、坝肩及边坡稳定的不同影响表明,坝址区地质条件对修建拱坝的适宜性较差,工程处理费用高,可实施性及实施效果有待论证;面板堆石坝虽然施工条件较差,但对地基要求低,对地质条件适宜性较好,工程处理难度较小,为可选坝型。

The river valley at the dam site of Jiangpinghe Hydropower Station is V-shaped with a width-height ratio of about 1. 8. It has the topographical conditions for building a high arch dam. However, when the valley slopes on both sides of the dam site, especially on the right bank, enters into the lower limit of weak weathering or slightly weathered rock mass, a large range of deep weathered rock mass appears. The influences of deep weathered rock mass on dam foundation deformation and dam abutment and slope stability of arch dam and face rockfill dam are analyzed respectively. The results show that,( a) the geological conditions in dam site area are not suitable for the construction of arch dam, the engineering treatment cost is higher,and the feasibility and the implementation effect need to be further demonstrated;and( b) although the construction conditions of face rockfill dam are poor, the requirements of face rockfill dam for the foundation are low, the suitability for the geological conditions is better, and the engineering treatment is less difficult, so the face rockfill dam is an option.