中文摘要：

根据已有研究将黄土高原按地貌及土的性质分为8个区,在各区现场识别出极限状态边坡,共测得510个极限状态黄土边坡断面,分区建立坡高与坡宽的拟合方程。取极限状态边坡的稳定系数Fs=1.0,基于拟合方程给出的坡高和坡度,用Morgenstern-Price法逐级反演获得各区20~120 m坡高的综合c、φ值。结果表明,随着边坡高度增加,c值线性增高,φ值非线性减小,并基于三轴试验结果揭示了该现象的本质是强度参数随应力变化的体现。不同高度边坡的反演结果都表明,黄土高原自西向东,自北而南,c值增大,φ值减小,这一变化规律与其成分及物理性质反映的特点一致。

英文摘要：

The Chinese Loess Plateau is divides into 8 zones according to the topographies and soil properties. The natural critical loess slopes are recognized and the profile of the slopes is surveyed at sites. Total 510 critical slope profiles are achieved in the 8 zones and the correlation equation between slope height H and width B is figured out for each zone, respectively. The critical slopes are supposed to be uniform simple slopes and have the factor of safety of 1.0. The shear strength parameters c and （ for the slopes with the height between 20 and 120 m are reversely calculated with the Morgenstern-Price method for the 8 zones, respectively. The results show that c increases linearly and （ decreases nonlinearly with the increasing slope height. The results of the tri-axial tests suggest that the changes in the strength parameters with slope heights are virtually caused by those with the increasing stress level. The higher the stress on the potential sliding surface, the higher the c value and the lower the （ value. The reversed c and （ with different heights of the slopes totally suggest that c increases and （ decreases from west to east and also from north to south, which are in accordance with the spatial variation of the particle size and physical properties of the loess on the Chinese Loess Plateau.