| 青海西宁大通县韩家山泥岩质多级旋转型滑坡形成机制研究 |
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| 关键词:landslide mud stone multi rotation lateral erosion of river formation mechanism progressive failure |
| 基金项目:国家自然科学基金项目(编号: 41402281);“十二五”国家科技支撑项目(编号: 2012BAK10B02)和中国调查局地质调查项目“青海湟水河流域地质灾害详细调查及大坡滑坡防治技术研究”(编号: 1212011220144) |
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| 全文下载次数: 1999 |
| 摘要: |
| The Formation Mechanism of Multilevel Rotational Mudstone Landslides in Hanjiashan of Datong County, Qinghai Province |
| There are 31 large-scale landslides in Xining Basin of Qinghai Province, and the Hanjiashan landslide in Datong County is one of the most dangerous. To analyze the deformation mechanism of that landslide, this paper described geometric and kinematic characteristics of the landslide and reconstructed the structure based on high-precision topographic data and continuous coring boreholes data. The authors conducted physical and chemical tests of the material composition, water-physical property and stress-strain property of the shear zone, described the process of mechanical property of shear zone on the basis of these quantitative tests, and then discussed the formation mechanism of multilevel rotational shear planes. Some conclusions have been reached: (1) there is no soft strata in slide mass; instead, the strata seem to be homogeneous formation. The slide mass is composed of red mudstone intercalated with gypsum horizon of Neogene, and both the gypsum and red mudstone are not in stratification and have no particles whose diameter is over 0.25 mm. The clay mineral content of the mudstone is 29.7%~46.3%, and the CaCO3 content is 9.84%~11.58%. The concretion of gypsum in the rock mass with different forms and dimensions may not have been formed by salt lake sediments; (2) the mudstone has high clay content, strong water sensitivity and viscosity. The lowest dry saturated water absorption is 26.31% and the highest is 42.12%. In ring shear test, the mudstone became strain softening, and the strength rapidly decreased when the moisture content increased. When the mudstone was in fast slide, the unsaturated slide zone could have strong suction due to the influence of sticky substances and porosity; (3) the mudstone of the slide mass was mainly in rotational deformation and the multilevel slide zone might have resulted from progressive damage of rock and earth mass and was probably influenced by lateral erosion of the river. Under the influence of lateral erosion of the river, the stress changed and concentrated at the foot of the slope, and the side stress of the adjacent rock mass which changed and concentrated by the fist slide would tend to cause the large-scale slide and progressive failure. |
| XIN Peng,WANG Tao,WU Shu-ren.2015.The Formation Mechanism of Multilevel Rotational Mudstone Landslides in Hanjiashan of Datong County, Qinghai Province[J].Acta Geoscientica Sinica,36(6):771-780. |
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