伊朗德伊高铁沿线高中溶盐粗颗粒盐渍土的渗透特性

Permeability Characteristic of Coarse Grained Salty Soil with the High Medium Soluble Salt Along Iran's Teheran-Isfahan High-speed Railway

为了探究高含量中溶盐粗颗粒盐渍土的渗透特性,依托伊朗德黑兰至伊斯法罕高速铁路项目,通过沿线盐渍土地基的现场浸水载荷试验与原位渗透试验,结合室内重塑盐渍土试验结果,对高含量中溶盐粗颗粒盐渍土的渗透特性进行研究分析。试验结果表明:中溶盐的含量对盐渍土渗透特性起着显著的影响,高含量中溶盐粗颗粒盐渍土的渗透溶滤变形主要由渗流场作用下石膏结晶颗粒遇水软化崩塌造成,与级配相似且中溶盐含量较低的盐渍土相比渗透系数均有大幅度降低;中溶盐含量越高,在荷载作用下渗透系数减小越明显;盐渍土粗颗粒所起的骨架作用越强烈,浸水过程中中溶盐含量对地基土的渗透特性的影响作用越不明显;对于不同颗粒粒径的盐渍土,在1%、3%、5%等不同中溶盐含量的范围内随着其含量的变化,渗透系数变化规律也不同;中溶盐含量超过一定范围时,呈现出中溶盐对盐渍土渗透性具有抑制作用的特征;中溶盐含量越低,易溶盐含量对其渗透性影响越显著。可见盐渍土颗粒粒径、中溶盐含量以及易溶盐含量对其渗透特性影响显著。

In order to explore the permeability characteristics of coarse grained salty soil with the high medium soluble salt,relying on Iran’s Tehran to Isfahan high-speed rail projects,based on field immersion load test and original position penetration test of saline soil foundation along the line,and combined with laboratory test results of remolding saline soil,permeability characteristics of coarse grained salty soil with the high medium soluble salt were studied and analzed.The results show that:the content of soluble salt has a significant effect on the permeability of saline soil.Percolation deformation of coarse salt-soluble soil with high content is mainly caused by the softening and collapse of gypsum crystalline particles under the action of seepage field.Compared with saline soils with similar gradation and lower medium soluble salt content,the permeability coefficient decreases greatly.The higher medium soluble salt content,the more obvious the permeability coefficient decreases under load.The stronger the skeleton effect of coarse grains of saline soil is,the less obvious the effect of soluble salt content on the permeability of foundation soil during immersion is.For saline soils with different particle sizes,the variation of permeability coefficient varies with the content of medium soluble salt in the range of 1%,3%,5%and so on.When the content of medium-soluble salt exceeds a certain range,it shows that medium-soluble salt can inhibit the permeability of saline soil.The lower the medium soluble salt content is,the more significant the permeability is affected by the soluble salt content.It is concluded that particle size,soluble salt content and soluble salt content of saline soil have significant effects on its permeability characteristics.