黄土滑坡不同发育阶段滑带土微结构变化研究

Aiming at solving the problems of microstructure features of loess slip zone in different developmental stages of loess landslides, Heifangtai Landslides in Gansu Province of China has been chosen as the research region. Being typical irrigation triggered landslides, the landslides receive much concern and are seen as natural validation site for landslide study. Firstly, based on engineering geology survey, digging exploratory wells, we will collect undisturbed slide zone samples in different developmental stages of loess landslides. Secondly, 2D and 3D images of loess slide zone are to be gained by a series of advanced testing technology such as SEM, Micro-CT and LSCM. Digital image processing techniques will be used to analyze micro-porous structure which includes image enhancement, image segmentation and feature extraction and so on. Characteristics of the pore distribution and spatial distribution of granular soils at different levels will be analyzed. Finally, this research attempts to measure the microstructure including the size and shape, spatial arrangement and distribution, contacting and concatenating way, then tries to find out developmental stages of loess landslides among them. The research's greatest characteristic lies in that we are going to study the loess microstructure in three-dimensional space and some new surface morphology parameters will be used to study slip surface.The research on this topic that has theoretical value and practical significance not only helps develop our insight into loess landslide mechanism, but also helps study landslide stability evaluation and landslide prediction further.

针对不同发育阶段黄土滑坡滑带土的微结构变化规律这一科学问题，以黑方台黄土滑坡群为研究对象,在不同发育阶段（未动、蠕动及滑动阶段）的黄土滑坡上采集滑带黄土样品，采用显微CT、激光扫描共焦显微镜技术获取滑带土及同层位原状黄土的三维图像，定性、定量地分析孔隙、颗粒在三维空间的分布状态，以这些图像为基础结合扫描电镜照片研究不同发育阶段黄土滑坡滑带土孔隙大小、分布以及土颗粒集合体的空间分布与联结的变化规律，探索微结构参数与滑坡发育阶段的关系。本申请思路与前人研究成果相比，其最大的特点在于：在三维空间研究黄土孔隙、颗粒分布，用表面粗糙度、纹理指数等综合指标描述滑面表面形态，在此基础上分析不同发育阶段滑带土的微结构特征。本研究对黄土滑坡机理研究、稳定性评价、监测预报以及防治具有重要的理论意义和应用价值。

以黑方台黄土滑坡群为研究对象，利用GPS、全站仪、小型无人机等现代化测绘手段，对黑台周边进行了详细的工程地质测绘，得到了台塬边缘高精度的DEM和正射影像，建立了滑坡的三维结构模型，分析了不同发育阶段滑坡的形态特征，结合工程地质调查、勘察资料，对滑坡结构进行了深入剖析；利用探坑及探井，对滑带土以及同层位原状黄土进行详细描述和取样，在黄土滑坡上采集了滑带黄土样品，对滑带土样品进行了系统的物理力学试验，研究了滑带土的土水特性、水敏性及不同应力路径下的力学性质，得到了滑带土的物理力学参数，系统分析了滑带土强度变化规律；采用光学显微镜、SEM、显微CT等微结构测试技术获取了滑带土及同层位原状黄土的图像，从颗粒分布、骨架连接方式、孔隙大小等方面，定性、定量地分析了孔隙、颗粒分布状态；对显微CT图像进行三维重建得到了不同土体的三维模型，计算了不同土体的颗粒、孔隙的大小和分布，统计得到了各级孔径、颗粒的数量及体积分布，进而对比了不同黄土微结构的差异；在此基础上，系统的研究了影响滑坡稳定性的因素及其作用方式，微观和宏观相结合，探讨了滑坡的发育机制。本研究对黄土滑坡机理研究、稳定性评价、监测预报以及防治具有重要的理论意义和应用价值。