含盐石英砂的毛细上升特性及其影响因素研究

Research on the Capillary Rising Characteristics and Influencing Factors of Salt-containing Quartz Sand

研究目的:地下水通过毛细作用不断侵入路基,严重时会导致路基冻胀、盐胀等病害,而密实度、初始含水率、含盐类型及含盐量都会影响毛细上升高度。本文通过对纯石英砂掺入不同类型和含量盐分,开展毛细水上升高度试验研究,对比分析在不同粒径级配、初始含水率条件下的毛细试验结果,并拟合出上升高度预测方程。研究结论:(1)毛细上升稳定高度随粒径减小而增大;在良好级配的条件下,细粒径含量的改变对毛细上升速度影响显著;(2)在4 000 min内,石英砂中掺入NaCl和Na_(2)SO_(4)会使毛细上升速度增大;(3)分别掺入两种盐分都会减小最终毛细上升高度,但NaCl的影响较小;(4)本研究成果可为控制毛细上升,处理盐胀、冻胀等病害提供借鉴和参考。

Research purposes:Groundwater continuously invades the roadbed under the capillary action,which will lead to frost heave,salt heave and other diseases of the roadbed in severe cases,and the capillary rise height will be affected by soil density,initial moisture content,salt type and salt content.By mixing pure quartz sand with different types and contents of salt,the capillary water rise height test is carried out in this research.The capillary test results under different particle size gradations and initial moisture content are compared and analyzed,and the prediction equation of rising height is fitted.Research conclusions:(1) The stable height of capillary rise increases with the decrease of particle size.Under the condition of good gradation,the change of fine particle size content has a significant effect on the rate of capillary rise.(2) Within 4 000 min,the capillary rising speed will increase when NaCl and Na_(2)SO_(4) are added into quartz sand.(3) The addition of two salts will reduce the final capillary rise height,but NaCl has little effect.(4) The research result can provide support for controlling capillary rise and dealing with salt heave,frost heave and other diseases.