不同干湿循环路径下盐渍化黄土侧限变形特性研究

Confined Compression Characteristics of Saline Loess under Different Drying-wetting Cycle Paths

针对干湿循环作用下盐渍化黄土侧限变形问题,系统开展了侧限压缩试验及溶陷试验,研究了氯盐盐渍化黄土在不同干湿循环路径、不同干湿循环次数及不同初始干密度下的一维固结压缩特性和溶陷变形特性。结果表明:压实盐渍化黄土的压缩变形随初始干密度的降低而增大,随干湿循环次数和增湿饱和度的增加而增大;土样e-lgp(e为孔隙比,p垂直压力)曲线变化幅度及压缩系数随初始干密度的减小和干湿循环次数的增多而增大;不同干湿循环路径下土样的e-lgp曲线在干湿循环次数低于5次时差异较大,在干湿循环次数达到10次时趋于一致;盐渍化黄土溶陷特性对各类条件的敏感程度依次为增湿饱和度、干湿循环次数、初始干密度。针对不同条件下盐渍化黄土溶陷系数曲线的不同表现形式,建立简易3参数模型,并与试验数据对比,表明该模型能够表征初始干密度及干湿循环次数对溶陷系数的影响规律。研究成果可为盐渍化黄土的干湿循环效应认知提供参考。

Aiming at the problem of confined deformation of salinized loess under the action of drying-wetting cycles,consolidation compression tests and melt-sinking tests were carried out systematically.The one-dimensional consolidation compression characteristics and settlement deformation characteristics of chloride saline loess under different dry wet cycle paths,different dry wet cycle times,and different initial dry densities were studied.Results indicate that the compressive deformation of compacted saline loess increases with the decrease of the initial dry density,and increases significantly with the increase of the number of drying-wetting cycles and the increase of humidification saturation.The e-lgp(e is void ratio,p is vertical pressure)curves under different drying-wetting cycle paths are quite different when the number of drying-wetting cycles is less than 5,and tend to be consistent when the number of drying-wetting cycles is 10.The sensitivity of salinized loess subsidence characteristics to various conditions is humidification saturation,number of drying and wetting cycles,and initial dry density.A simple 3-parameter model was proposed for the different manifestations of the meltsinking coefficient curves of salinized loess under different conditions,which can better characterize the change of the melt-sinking coefficient with different initial dry densities and different drying-wetting cycles.The research results can provide a useful reference for the cognition of the dry-wet cycle effect of salinized loess.