黄土崩塌是指在自重及外荷载的作用下，高陡边坡上的黄土体突然从母体崩落的现象，是黄土地区常见的地质灾害，危害极大。为了合理地分析和计算黄土崩塌的破坏过程，有效地指导崩塌灾害的防灾减灾工作，构建一种崩塌稳定性计算模型是目前迫切需要解决的重点课题。 黄土崩塌的形成因素主要包括边坡的几何形态、岩土性质、地质结构面等。论文基于滑移式黄土崩塌的变形破坏特点，采用DEM对崩塌块体进行力学分析，计算其运动过程，并结合计算机图形显示技术对其可视化。主要包含三方面的研究内容：黄土边坡离散元模型的构建、块体单元的应力-位移计算以及崩塌过程的可视化。其中，块体划分是离散元模型构建的一个重要环节，划分结果的合理性与否将直接影响崩塌过程模拟的准确性。针对传统DEM采用相同大小的单元划分块体而忽略崩塌体的实际破坏特征，本文引入对数螺旋滑裂面模型对其进行优化，以保证划分结果的合理性。 选取宝鸡市陈仓区坪头镇码头村黄土崩塌作为工程实例，对滑移式黄土崩塌的形成过程进行数值模拟与分析。研究给出该崩塌变形破坏过程的四个阶段：垂直节理张开—坡体变形失稳—崩塌块体运动—崩塌体堆积。通过分析码头村黄土边坡前缘9个特征点的位移变化趋势，可以看出：较边坡前缘的中、后部而言，前部崩塌块体的位移较大，且竖直位移的变化趋势与其高程正相关，这与崩塌体的实际破坏规律是比较符合的。实例计算表明，论文给出的黄土崩塌稳定性计算模型，能够为崩塌灾害的防治和预警提供科学的理论指导，具有一定的理论价值和现实意义。

Loess collapse is a kind of geological phenomenon, which refers that the loess mass collapses and separates from the matrix of the high and steep slope in the action of gravity and external force, and is more common in loess area as a harmful disaster. In order to analysis and calculate the failure process of loess collapse reasonably, and provide the basis for guiding the disaster prevention and reduction work effectively, building a collapse stability calculation model is now a needed urgently core topic. The formation factors of loess collapse mainly include the slope geometry, soil properties, geological structure plane, etc. According to the characteristics of sliding loess collapse and failing model, this paper used the DEM(Distinct Element Method) to make a mechanical analysis for collapse mass, and calculated its motor process, also combined with the computer graphics technology for visualization. It mainly includes three aspects of the research content: the construction of discrete element model for the loess slope, the force-displacement calculation of blocks and visualization for all units. Among them, block division is an important link of the construction of discrete element model, and the rationality of the division results will affect the accuracy of collapse process simulation. In view of traditional DEM, considering dividing blocks in same size may neglect the actual failure characteristic of collapse, this article used the model of sliding surface in logarithmic spiral shape to optimize the segmentation process, which made its result more reasonable. This paper took a loess collapse case for example, which located in Matou village, Pingtou town, Chencang district of Baoji city, Shaanxi province, then made a numerical simulation and analysis of its failure process. Based on the simulation results, the deformation and failure process of the collapse can be summarized to four stages: split of vertical joints—slope deformation and instability—the movement of collapse block—the accumulation of collapse body. By analyzing the displacement change trends of nine feature points in loess slope, it can be seen that the displacements of front collapse blocks are larger than the hind blocks’. Meanwhile, the vertical displacement change trend is interrelated to slope’s altitude positively, which is more consistent with the actual failure law of collapse. The instance calculation shows that, the calculation model above can provide theoretical guidance for the prevention and warning of collapse disasters, and has vital theoretical and practical significance.