摘要
砂砾石料细颗粒含量多、易于压实,在重型碾压机具作用下,压实后砂砾石料的孔隙结构和渗透特性可能发生改变,将影响高混凝土面板砂砾石坝坝体渗流安全。开展压实后砂砾石料渗透试验,分析砂砾石料特征粒径与等效孔隙直径的关系,以及不同孔隙率对砂砾石料渗透特性的影响,并对常用的渗透系数经验计算式进行验证。研究表明:砂砾石料孔隙率的减小对其渗透特性影响较大,由于砂砾石料细颗粒含量较多,压实后颗粒填充紧密,渗透试验得出的渗透系数比常规经验公式计算值小1~2个数量级,出现较大偏差;随着孔隙率减小到一定程度,砂砾石料表现出黏性特性,内部无效孔隙增加、渗透系数大幅降低。基于中国水科院公式引入有效孔隙折减系数对公式进行修正,修正后公式计算得到的结果更加准确。研究成果可为高混凝土面板砂砾石坝坝体排水设计提供依据。
The sand gravel has more fine particles and is easy to be compacted.Especially under the action of heavy roller,the pore structure and permeability characteristics of the sand gravel may change after compaction,which will affect the seepage safety of the high concrete face gravel dam.In this research,the permeability test of sand gravel after compaction was carried out to analyze the relationship between the characteristic particle size and the equivalent pore diameter of sand gravel,as well as the influence of different porosities on the permeability of sand gravel,and verify the commonly used empirical calculation formula of permeability coefficient.The research shows that the reduction of the porosity of the sand gravel has a great impact on its permeability characteristics.Due to the large content of fine particles in the sand gravel,and to the fact that the particles are tightly packed after compaction,the permeability coefficient of the sand gravel obtained from the permeability test is 1~2 orders of magnitude smaller than the calculated value of the conventional empirical formula,resulting in a large deviation.As the porosity decreases to a certain extent,the sand gravel shows certain viscous characteristics,the internal void increases,and the permeability coefficient decreases significantly.Based on the formula of China Institute of Water Resources and Hydropower Research,the effective pore reduction coefficient is introduced to modify the formula,and the results calculated from the modified formula are more accurate.This study can provide a basis for the drainage design of high concrete face gravel dams.
作者
邓成进
周恒
党发宁
苗喆
DENG Chengjin;ZHOU Heng;DANG Faning;MIAO Zhe(Northwest Engineering Corporation Limited,Xi’an 710065,China;Institute of Geotechnical Engineering,Xi’an University of Technology,Xi’an 710048,China)
出处
《水利水运工程学报》
CSCD
北大核心
2023年第3期121-129,共9页
Hydro-Science and Engineering
基金
国家自然科学基金联合项目(U1965107)。
关键词
砂砾石料
渗透特性
孔隙率
有效孔隙折减系数
sand gravel
permeability characteristics
porosity
effective pore reduction coefficient
