贴砾过滤器贴砾层渗透性试验研究

Experimental study on permeability of the pre-packed layer in pre-packed screen pipe

摘要:

贴砾过滤器、砾石充填在地热开采、水文观测等工程中得到了广泛应用。他们的主要工作部位为贴砾层、充填层，研究最常用的贴砾材料石英砂的渗透性能。通过调节砂样的粒径、细颗粒含量，测试砂样固结前后在饱和状态下的渗透性，分析粒径、级配对砂样固结前后渗透性的影响，通过试验数据整理，分析相同条件的砂样固结前后的渗透性能差异。试验表明，固结前后的砂样的渗透系数随粒径的减小而减小，在中砂范围内变化最大，在细砂范围变化较小；固结前后砂样的渗透系数都随着细颗粒含量的增多而减小，复配砂的最小渗透系数小于构成其细颗粒组砂的渗透系数；相同条件下，粗砂范围内，石英砂的渗透性能要优于固结后的石英砂，中细砂范围内，固结后的石英砂的渗透性能要优于石英砂。

Abstract:

Pre-packed screen pipes and gravel packing are widely used in geothermal exploitation， hydrological observation and other projects. The main working parts are gravel layer and pre-packed layer. In this paper， the permeability of quartz sand was researched which is commonly used as the pre-packed material. Through adjusting the particle size and fine particle content of the sand samples， the permeability of quartz sand before and after consolidated in saturated state is tested， the effects of the particle size and gradation on the permeability of quartz sand before and after consolidated are analyzed， and the permeability difference in the same conditions is also analyzed by sorting the tested data. The results show that the permeability coefficient of sand samples decreases with the particle size. Changes in medium sands is the biggest and smaller in fine sand. The permeability coefficient of sand samples decreases as the fine particle content increases. The minimum permeability coefficient of composite sand is smaller than that of the sand that constitutes its fine particle group. Under the same conditions， the permeability of loose coarse quartz sand is better than that of the consolidated quarts sand， and the permeability of the medium and fine consolidated quartz sand is better than that of loose quartz sand.