引汉济渭工程三河口水库拱坝坝基岩体质量特征与建基面优化选择

Quality Characteristics and Optimization Selection of Arch Dam Foundation Rock Mass of Sanhekou Reservoir for Hanjiang-toWeihe River Water Diversion Project,China

研究坝基岩体质量有助于合理选择建基面,为工程设计、施工和安全运行提供科学依据。以引汉济渭工程三河口水库拱坝坝基岩体为研究对象,通过对坝基开挖揭露的岩体重新进行勘探试验,利用勘探孔进行孔内电视、纵波波速及变形模量等测试工作,对坝基岩体风化特征、结构特征、变形模量与纵波波速关系等问题进行综合分析研究,特别是对坝基局部的断层破碎带及碎裂岩体能否利用等问题进行了具体分析,并对坝基岩体质量进行了工程地质分类,选出了符合实际的建基面,使大坝建基面高程由原来的501.0m抬升至504.5m,优化了坝基开挖深度,减少了坝基处理难度与混凝土浇筑量,缩短了工期,节约了工程投资。

Study on the quality of dam foundation rock mass will help to reasonably select the foundation surface, and provide a scientific basis for engineering design, construction and safe operation. Taking the dam foundation rock mass of Sanhekou reservoir for Hanjiang-to-Weihe river water diversion project as the research object, the rock mass exposed by the dam foundation excavation was re-explored; meanwhile, the weathering characteristics, structural characteristics, relationship between longitudinal wave velocity and deformation modulus of dam foundation rock mass were elaborated comprehensively by using the test of the downhole television, longitudinal wave velocity, deformation modulus with prospecting holes; and the utilization of fault fracture zone and cataclastic rock of the dam foundation was analyzed emphatically, and a detailed engineering geological classification of dam foundation rock mass was discussed. Finally, the practical foundation surface is selected to raise elevation of the dam foundation plane from 501.0 m to 504.5 m, which optimizes the excavation depth of dam foundation, reduces the difficulty of dam foundation treatment and concrete pouring, and saves construction period and project investment.