裂隙岩溶介质渗透性变异规律的尺度效应

Scale effect of permeability variation pattern of fracture-karst media

裂隙岩溶介质渗透系数尺度效应的研究为岩溶地下水渗流模拟中渗透系数的选取以及工程实际问题的解决提供参考。为探讨裂隙岩溶介质渗透系数的尺度效应及产生机理,将示踪试验、抽水试验和室内渗流实验相结合,从微观和宏观两方面进行定量化研究。结果表明:因裂隙岩溶介质的非均质性和发育规模的多级次性,随着试验尺度从微米级增大到10^(3)m,水平渗透系数从10^(-1)m/d增大到10m/d,且试验尺度突破一定范围时,其与渗透系数之间关系由对数关系转为线性关系,最终渗透系数趋于稳定;受岩体和地层的自重应力作用,随着埋深的增加,岩溶发育程度降低,垂向渗透系数逐渐减小。该研究成果有助于进一步阐明地下水运动规律,为地下水环境保护提供可靠依据。

The study on the scale effect of hydraulic conductivity of fracture-karst media provides reference for the selection of hydraulic conductivity in simulation of karst groundwater seepage field and solution of practical engineering problems.In order to explore the scale effect and generation mechanism of hydraulic conductivity of fracture-karst media,a quantitative study was carried out from both micro and macro aspects by combining tracer test,pumping test and indoor seepage test.The results show that:due to the heterogeneity of fracture-karst media and the multi-level development scale,the horizontal hydraulic conductivity increases from 10^(-1)m/d to 10m/d as the test scale increases from micron scale to 10^(3)m.When the test scale breaks through a certain range,the relationship between it and hydraulic conductivity changes from logarithmic relationship to linear relationship,and finally the hydraulic conductivity tends to be stable.Under the action of the self-weight stress of rock mass and stratum,the degree of karst development decreases and the vertical hydraulic conductivity decreases with the increase of buried depth.The research results are helpful to further clarify the law of groundwater movement and provide a reliable basis for groundwater environmental protection.