考虑中溶盐作用下的结构性黄土强度准则

以西安地区Q₂^eol黄土为研究对象,采用室内试验和理论研究的方法探究以CaSO₄为代表的中溶盐含量对原状黄土结构性强度的影响。通过对4种不同含量(0、0.476、0.952、1.904 g/L)的CaSO₄溶液饱和下的黄土试样进行不同围压(50、100、200、400 kPa)的三轴固结不排水剪切试验,测定并分析结构性黄土试样强度的变化规律。结果表明,该土样的应力-应变关系曲线均呈硬化型,且在同一围压作用下,黄土强度随中溶盐含量的增大呈先快增再缓增的趋势。基于岩土体的二元介质模型,对结构性土体的强度准则进行修正,得到与中溶盐含量相关的剪切抗力分担率参数,建立了适用于西安地区考虑中溶盐含量的结构性黄土强度准则,为具有该特性的黄土区域建设提供参考。

Modification of Structural Loess Strength Criterion Considering the Effect of Moderately-soluble Salt Content

With the Q₂^eol loess in Xi’an as research object, the influence of the content of moderately-soluble salt represented by CaSO₄ on the structural strength of undisturbed loess was explored by means of laboratory test and model establishment. Triaxial consolidated undrained shear test was conducted on loess specimens saturated with CaSO₄ solutions of different concentrations(0,0.476,0.952,1.904 g/L) under varying confining pressures(50, 100,200, 400 kPa). The change rules of structural strength of loess were measured and analyzed. Results suggest that the stress-strain curves of the soil specimens displayed hardening features. Under the same confining pressure, the loess strength augmented rapidly and then slowed down along with the increase of soluble salt content. In addition, based on the binary medium model of rock and soil mass,the strength criterion of structural soil mass was modified to obtain the shear resistance sharing rate related to the content of moderately-soluble salt,and the strength criterion of structural loess in consideration of moderately-soluble salt content suitable for Xi’an was established.