盐分及含水率对甘肃黑方台黄土强度的影响研究

文章以甘肃黑方台灌区黄土滑坡区黄土为研究对象，开展了滑坡区盐分调查及水土化学特征分析，进行了不同易溶盐含量及不同含水率条件下的重塑黄土三轴固结不排水剪切试验，探讨盐分及含水率对黄土强度的影响。结果表明：滑坡区土样中易溶盐含量范围为0.15%～4.55%,易溶盐主要是以Na₂SO₄和NaCl为主；水化学分析显示灌溉水入渗及溶滤台塬黄土中的可溶盐，经优势通道在坡脚以泉点渗出等方式排泄并富集；试样抗剪强度随易溶盐含量的增加而提高，随含水率的增加而降低；不同易溶盐及含水率条件下，抗剪强度参数黏聚力变化范围为4.2～57.1 kPa,内摩擦角变化范围为23.1°～33.5°,黏聚力对易溶盐及含水率的变化更敏感。

Effects of salinity and moisture content on the strengthof loess in Heifangtai, Gansu Province

The loess in the landslide area of the Heifangtai irrigation district in Gansu Province was taken as the research object in this study. The salt content and the chemical characteristics of the soil and water in the landslide area were investigated. A series of triaxial consolidation undrained shear tests was conducted on remolded loess with different soluble salt contents and moisture contents to explore the effects of the salinity and moisture content on the shear strength of the loess in this region. The results showed that (1) The soluble salt contents in the samples ranged from 0.15% to 4.55%, and the main components were Na₂SO₄ and NaCl. (2) The hydrochemical analysis showed that the irrigation water infiltrated and dissolved the soluble salt in the plateau loess, which was discharged and enriched at the slope foot in the form of spring point seepage. (3) The shear strength of the samples increased with the increase in the soluble salt content and decreased with the increase in the water content. (4) Under the conditions of different soluble salts and water contents, the cohesion varied from 4.2 kPa to 57.1 kPa, and the internal friction angle varied from 23.1° to 33.5°. The cohesion was more sensitive to changes in the soluble salt and moisture contents.