为了研究结构性原状黄土在加载条件下的破坏特性，采用试验的方法对Q2原状黄土进行了非饱和土三轴剪切试验研究。基于试验成果，定义了可以考虑球应力、偏应力和基质吸力等因素的土的结构性变量参数m。利用通过试验提出的m的计算方法，找出抗剪强度参数c、 值与m之间的关系，推导出m与c、 值的曲线方程，分别将曲线方程代入到Drucker-Prager（D-P）准则方程中对其进行修正，建立了结构性Q2原状黄土的修正屈服准则，该准则可以考虑Q2原状黄土的结构性影响，符合黄土的结构性特性，绘制出可反应结构性参数影响的屈服面，并验证了其合理性。

To investigate the destruction characteristics of intact structural loess under loading conditions, triaxial shear tests are conducted on Q2 intact loess. Based on the experimental results, a structural variable parameter m of soil is defined, which can consider the spherical stress, deviatoric stress, matric suction and other factors. By means of method for calculating the structural parameter m based on the experiment, the relationships among shear strength parameters c, and structural parameter m are found out, the curve equations of m with c, are deduced, respectively. By introducing the curve equations into Drucker-Prager (D-P) criterion, a modified yield criterion applicable to Q2 intact loess is established. The modified yield criterion can consider the structural effect of intact Q2 loess and describe the structural characteristics of loess very well. Besides, the yield surface reflecting the impact of structural parameters is drawn. The rationality of the modified yield criterion is verified by comparing the results of the modified yield criterion with those obtained from the triaxial tests.