黄土高原北部的黄土由于含砂量高, 广泛发育一种既不同于黄土滑坡、又不同于黄土崩塌的独立地质灾害类型——黄土滑塌。由于砂黄土的弱胶结性使得黄土滑塌呈现出某些不同于典型黄土滑坡的特点。从分布区域上看, 它位于黄土高原的I带, 即砂黄土带;从发育的典型地质环境看, 受制于当地特殊的土地资源和居住条件;从风险特征看, 有“坍窑不坍掌”的特点;从诱发因素看, 是降雨、冻融、冻胀、人工开挖等各种因素的综合作用。关于其变形破坏机制, 不同的学者提出了不同的见解, 有先塌后滑式、先滑后塌式、中部向两头延伸式和整体错落式, 最新的研究表明其符合下部剪切破坏上部拉张倒塌模式, 至于其微观机理方面的研究还很少。今后的研究应进一步查明诱发因素, 总结该类滑坡变形破坏特征, 综合运用数值和物理模拟手段, 建立不同诱发因素影响下的地质力学模型, 基于应力—应变关系, 定量分析黄土滑塌的变形破坏机制, 阐明其微观机理。

There has widely developed a specific kind of landslide-loess slump in the north of loess plateau in China, which is different from loess slide or loess fall because of the high sandy ingredient in loess. Due to the weak cement of sandy loess, the slump shows some other features than “typical” loess landslide. In distribution scopes, it often occurres in sandy loess belt, beyond that there are clay loess belt and silty clay loess belt. Due to the extreme shortage of land resources, the local people often choose the concave banks of valley as the cave dwellings sites whereas the convex banks are kept to develop agriculture. Generally, the concave banks have already been eroded much by rivers which makes the level stress of the slope release. However, the excavation for constructions reduces the level stress furthermore. Therefore, it causes the shear stress increase at the feet of the slope. The equilibrium state of the slope is destroyed, and then the failure occurres. The triggering factors of loess slump include rainfall, freeze thawing, freeze swelling, excavation, etc. In fact, these factors often comprehensively affect the slumps. In terms of their deformation and failure mechanism, scientists put forward different views, which include falling firstly and sliding secondly, sliding firstly and fall secondly, from middle parts rupture extending to top and bottom, and integrated sliding and falling. The nearest research implies that the failure mechanism be the bottom shearing failure and then the top tension failure. Referring to the failure mechanism at a micro level, few researches have been done to this kind of landslide. Future studies should investigate the triggering factors widely and deeply, summarize the characteristics of the deformation and failure, apply the numerical and physical simulation methods comprehensively, build up the geological-mechanic model, analyze and clarify the deformation and failure mechanisms quantitatively on the basis of strain and stress relationship, and study the failure mechanisms on a micro level.