The Study Of Expansive Soil Landslides And The Risk Assessment Methods Of Expansive Soil Landslides

Mianxian County is located in the southeast of Shannxi Province with Hanzhong Basin in its south and QingLing in its north. Vary geological disasters would hit the place with landslide beening the seriouset one. There are 112 landslides in Mianxian County among which are 23 expansive soil landslides. Because of the large population density and the frequently human activities of this area, the disasters would cause great damage. So make research of the special soil landslides'characteristics and its risk assessment methods will provides support for the early warning and the prevention.In this thesis, the author sums up the flat surface form, the section form and the types of the landslides of the expansive soil landslides in Mianxian County through imformation collection, outdoor survey and the locale measurement, then analyses the reason of why they are of small size, shallow slide face and manly scattered along Hanjiang River. Firstly Mapgis is used to analyses the distribution characteristics of the disaster sites; secondly, scanning electron microscope, X-ray diffraction experiment and other experiments have been employed to research the expansive soil's structure, the mineral components and the contents & physical property of the slide soil. The expansive soil is of weak or medium expansibility and it has apparently relationship with the mineral components and the mineral contents; thirdly, the risk assessment methods have been selected according to the traits and the formation factors. Meanwhile, quantitative and qualitative evaluations has been given to the landslides. At the end, the mini pile prevention method is suggested to be used in Mianxian County.