黄土结构屈服损伤与其土水特征的关系

Study on Relationship between Loess Structure Yield Damage and Soil-water Characteristics

通过非饱和土固结仪对原状黄土进行土水特征、压缩变形特性的试验研究,系统分析了原状黄土结构屈服损伤特性与其土水特征之间的关系。试验结果表明,原状黄土基质吸力随着竖向净压力的增大呈先增大后减小的变化趋势。定义基质吸力临界压力,发现基质吸力临界压力随着含水量的增大而减小。通过原状黄土及相应的饱和正常固结黄土的压缩曲线特征提出一种确定原状黄土结构屈服压力的新方法,该方法具有受压缩曲线形状影响较小、精度较高且作图简便等特点。统计得到原状黄土基质吸力临界压力与其结构屈服压力近似相等,进一步分析原状黄土结构屈服损伤破坏机理。

The characteristics of soil-water and compression deformation of intact loess were studied by unsaturated soil consolidating instrument and also the relationship between yield damage characteristics and soil-water characteristics of intact loess was systematically analyzed.The test results show that the matrix suction of intact loess increases and then decreases with the increase of vertical net pressure.The critical pressure of matrix suction is defined and it is found that the critical pressure of matrix suction decreases with the increase of water content.A new method for determining yield stress of intact loess is proposed by analyzing the characteristics of compression curve of intact loess and corresponding saturated normal consolidation loess.The method is less affected by the shape of compression curve and also has the advantages of high accuracy and simple drawing.Statistics shows that the critical pressure of matrix suction is approximately the same as the structure yield pressure.The failure mechanism of intact loess structure is further analyzed.