乌东德水电站特高拱坝施工期坝基岩体质量工程地质评价

Geological Study of Rock Mass Quality of Wudongde High Arc Dam Foundation Under Construction Period

特高型拱坝坝拱座岩体承受的荷载巨大,坝基岩体质量是拱座稳定的关键,在施工期如何准确评价坝基岩体质量,是拱坝建基岩体工程地质研究的重要问题。本文以工程地质条件研究为基础,从岩性、岩体结构分布着手,研究建基岩体工程地质特征;以现场、室内试验、声波测试为依据,建立坝基岩体质量评价标准。对乌东德拱坝施工期揭露的建基面岩体进行质量划分,研究发现:乌东德拱坝建基岩体质量优良,以Ⅱ级岩体占绝大多数,少量Ⅲ1级岩体,极少量Ⅲ2级岩体,与可研成果高度吻合;建基岩体满足岩体质量与声波验收要求,岩体质量空间分布较连续,且相对均匀,有利于承受拱坝推力。

The most load of the arc dam is transmitted to the abutment rock mass of both sides through the arch dam foundation.How to accurately evaluate the quality of dam foundation rock mass during construction period is important for engineering geology research of arch dam foundation rock mass.Based on the engineering geological conditions,the authors studied the engineering geological characteristics of foundation rock mass,such as lithology and rock mass structure etc.,and built the rock mass quality classification standard,combining with the field and laboratory tests and the sonic test of rock mass.According to the rock mass quality classification during excavation,most of the rock mass is of gradeⅡ,a small amount of gradeⅢ1,and very small amount ofⅢ2,which are agreed with the result of the feasibility study stage.The quality of rock mass meets the requirement of dam construction.The distribution of rock mass is continuous and beneficial to the arch dam.