内陆寒旱区粗粒盐渍土赋存特征与成生模式研究

Occurrence characteristics and formation models of coarse saline soil in inland cold and arid regions

我国西北内陆寒旱区盐渍土分布广泛,公路路基病害突出,给公路建设、运营及养护带来了很大困难。通过在甘肃河西地区多个公路项目沿线开展工程地质调绘、地基挖探及岩土测试等研究,揭示了内陆寒旱区粗粒盐渍土的赋存特征和成生模式。研究表明,内陆寒旱区粗粒盐渍土中盐分主要以带状晶簇、连片状晶簇、块状结晶、不连续状盐华等形态赋存于土体中,内陆寒旱区粗粒盐渍土的分布总体表现为距山前越远而埋深越小、氯硫比越大,随埋深增大含盐量逐渐减小,具有平面分布的不均匀性和垂向分布的差异性,其成生模式可归结为由地层成因和地形地貌控制、受气候条件影响的典型冲洪积盐渍土。

Saline soil is distributed widely in inland cold and arid region of Northwest China.Serious roadbed diseases caused by saline soil may bring many difficulties to highway construction,operation and maintenance.Geological mapping,trial pit excavation and geotechnical testing were carried out along several highway projects in Hexi region of Gansu Province,the occurrence characteristics and formation models of coarse-grained saline soil in inland cold and arid regions are revealed.The research shows that the salt content of coarse-grained saline soil in inland cold and arid regions is mainly in the form of banded crystal clusters,continuous flake crystal clusters,massive crystals and discontinuous salt blooms.The distribution of coarse-grained saline soil is generally shown as the farther away from the mountain,the smaller the buried depth and the larger the chlorine-sulfur ratio,and the salt content decreases gradually with the increase of burial depth.The inhomogeneity of plane distribution and the difference of vertical distribution are the main occurrence characteristics of coarse-grained saline soil in inland cold and arid regions.The formation models are controlled by stratigraphic genesis and topography which are the typical alluvial and diluvial saline soils affected by the climatic conditions.