| A heavy geologic hazard of landslide happened in Darong Village of Siyang, Cenggong County, Guizhou Province on29th of June,2012. In this landslide,9wooden houses are destroyed, and over300farmers’life and agriculture production are directly afflicted by the disaster. Slip mass stops the Mapo creek which is below the slope and forms avalanche lake. Over one thousand people’s life and property safety are threatened. After the disaster of slope falling and barrier lakes’s reflowing, people care much about whether the slope loses balance again. And salability after landslide influences land’s re-cultivation and decision of project measures. Based on the scientific research project A Study of Early Warning System and Decision Support Terrace of Geologic Hazard in Guizhou Province, the author takes part in the field survey of the landslide. In addition, the author collects relative data and analyzes the characteristics and mechanism originesis of landslide. Besides it, the author also studies and chooses proper monitoring technology method and instrument, formulates and implements rational automated monitoring project. Based on the monitoring result, the author evaluates deformation characteristics and estimation of stability of landslide. By the numerical simulation, the author inspects and verifies the influence of secondary slide surface to slope deformation. Then the author uses strength reduction method and ultimate balance theory to evaluate stability of landslide. The main findings are listed as follows:Firstly, based on the analysis of landslide morphological character, slip mass structure and characteristics of motorial accumulation body, the slope can be divided into four regions. Heaping in the starting zone of landslide breaks the seepage piping systems of gravel-like soil. When it rains, rain into the seepage piping systems is so difficult to be drained that it will raise the groundwater level, lowering the stability of slope. Thus, the author considers that surcharge and rainfall are main and direct factors which cause the landslide. Secondly, because of the heavy rain in the middle July in2012, obviously big displacement deformation happens to the surface displacement monitoring point which is set on the land in the area that suffers terrible instability and serious deformation after landslide. But some other monitoring points are not obvious in displacement deformation despite the raining in later period. Therefore, the slope is influenced more heavily by the first raining after landslide.Thirdly, sliding inclinometer monitoring data reflect that the rock on the original slippery slope section takes on the signs of backward deformation, and the deformation is obviously influenced by layer lithology and fracture in the slant hole area. The numerical simulation study verifies that the backward deformation happens because of secondary sliding surface and gravity of rock mass in the crack. Fixed inclinometer monitoring data reflect that continuous rainfall on landslide area will get "the lower part"deformation to increase, because after the rainfall there will be a slight back; in the arid climate,"the lower part" deformation decreases. This suggests that the displacement of deep rock mass is closely related to the groundwater activity caused by rainfall.Fourthly, the outcome of computational stability shows that landslide in Darong Village is in a steady state in the native state. However, the entirety is in a stable state and the part is in a stable or unstable state in rainstorm state. The landslide deformation is sensitive to the response of c、 φ values. In addition, the ramollescence of rainfall has an obvious influence to landslide stability. |
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