摘要
在坝址区开展裂隙水文地质研究具有重要的理论意义和实用价值。采用表征岩体渗透性的单位吸水量为参数,有效地分析了砂泥岩裂隙岩体中自重应力和岩性对渗透性空间分布规律的控制作用。研究区内,渗透性表现出显著的随机性特征。研究发现,单位吸水量随绝对深度呈分型关系减小的变化规律可以较好地反映自重应力对裂隙岩体渗透性的控制;将自重应引起对单位吸水量减小的趋势剔除以后,再将残差项在不同相对深度上取均值,可以较好地反映岩性对渗透性的控制作用。此外,研究还发现,即使压水试验段本身不含软岩,泥岩出现概率高的相对深度对应的渗透性还是会偏小。这些规律为裂隙岩体的渗流计算和模拟奠定了基础。
Conducting research on fractured media hydrogeology in dam site has both theoretical and practical significance. In this paper, the spatial variation of permeability with geostress and lithology in a formation of fractured Sandstone-Mudstone media is analyzed. The permeability value is represented by unit absorption w in each five-meter test section obtained from packer permeability test. The variability of permeability in sandstone is so significant that the value of w span 3 to 4 orders of magnitude at different depths, including absolute depths and relative depths. We found that the variation of permeability with absolute depth obey the fractal law, which is caused by geostress; After subtracting the trend of w with absolute depth, the residual value of log w in each 5m are discretized into 1m and then average value are taken at each relative depth, the mean of residual value at each relative depth can be well correlated with distribution of mudstones. In addition, an interesting phenomenon is found, although no mudrock is shown in the test sections analyzed, the distribution of mudrock still influence the overall distribution of permeability.
出处
《工程勘察》
CSCD
北大核心
2008年第S1期210-216,共7页
Geotechnical Investigation & Surveying
关键词
裂隙岩体
渗透性
自重应力
软岩分布
相对深度
fractured media
permeability
geostress
distribution of mudstone
relative depth
