Abstract: The major dam shell of Xiaolangdi water conservancy project is filled with rockfill materials containing siltstone, clay rock and other soft rocks. After years of operation, the soft rocks on dam surface have weathered into fragments, and part of soft rocks have been eroded into rockfill voids, which will have a certain impact on the physical and mechanical properties of rockfill materials in the dam shell, such as the permeability coefficient and shear strength, and may also affect the stability of upstream and downstream dam slopes. At the same time, Xiaolangdi dam has large dam height, complex and deep overburden, many kinds of dam materials and complex operating conditions, so it is necessary to study the properties of rockfill materials in dam shell. Through in-situ excavation and sampling, relevant tests of the grading, compactness and permeability of rockfill materials and original rock character and strength are carried out to conduct the experimental study on properties of rockfill materials in the major dam shell. The results show that the main character parameters of rockfill materials in the major dam shell slightly changed, and the weathering degree and compressive strength of rockfill materials have limited influence.

Key words: rockfill material in dam shell, weathering degree, experimental study on properties

摘要： 小浪底水利枢纽主坝坝壳采用含粉砂岩、黏土岩等软岩的堆石料填筑，经过多年运用，坝体表面软岩部分 已风化呈碎块状，部分软岩已冲蚀入堆石空隙，对坝壳堆石料的渗透系数、抗剪强度等物理力学性质产生一定影 响，也可能影响大坝上、下游坝坡的稳定。同时，小浪底大坝坝高较高，覆盖层结构复杂且深度大，筑坝材料种类 多，运行条件复杂，因此对坝壳堆石料性状开展研究非常必要。通过现场挖坑取样，进行堆石料级配、密实度、渗 透性及原岩岩性、岩石强度等相关试验，开展主坝坝壳堆石料性状试验研究，结果显示主坝坝壳堆石料的主要性 状参数略有变化，坝壳堆石料的风化程度、抗压强度影响有限。

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