| Southwest of our country is relatively concentrated area of earthquake, the rainfall is big. These factors are the reason why the geological disasters occur frequently in southwest China’s (such as landslide, collapse, debris flow). Most of scholars at home and abroad are only consider unilateral factor (rainfall or earthquake) in the research on the formation mechanism of landslide, while considering rainfall infiltration and earthquake dynamic effects of the related research is less. This article, based on an example of the Muer landslide, analysis rainfall infiltration, earthquake, the impact of both the combined effect on the Muer landslide. This has important theoretical and practical significance.This paper uses the field geological survey, qualitative analysis combining numerical calculation method to research. The main research works and achievements are as follows:1. Through investigation of landslide area, the geomorphological features of landslide belongs to the typical erosion tectonic geomorphology. Based cladding interface has a larger, this provides a terrain conditions for the occurrence of landslide. The abundance and long time of rainfall and seismic activity frequently within the landslide area provide a power condition for occurrence of the Muer landslide.2. It reveals the rain effects on the Muer Landslides flow field via studying different rainfall conditions.(1) This article study five different rainfall intensity (5 mm/d、20 mm/d、40 mm/d、 60 mm/d、85.4 mm/d). After the rain two days, the underground water table of landslide body is gradually rising with the increase of rainfall intensity and rainfall time. When the rainfall intensity exceeds a certain value, the uplifting of the underground water table is very slow.(2)The article studied a landslide body change law of underground water table in the process of rainfall. It have selected the local maximum rainfall 85.4mm as rainfall intensity.After rain stopped two days later, the underground water table is not immediately fall. The underground water table reached the highest water table and to fall after the rain stopped for a period of time.3. The paper assuming different rainfall conditions, analysis of rainfall intensity, rainfall duration, a rainfall process to study the effects on the stability of the Muer landslide.(1) Under the same rainfall duration and different rainfall intensity, stability safety factor of landslide intensity decrease with the increases of rainfall.(2) As the rainfall time continues, the slope stability safety coefficient changing with time of curves performance into nonlinear decreasing. On the whole, the landslide of stability is gradually reduce. This is because landslide sliding force are increase with the pore water pressure rises. Besides, the softening of rainfall also reduces the stability of the landslide. Stability safety factor of landslide will gradually decrease.(3) This paper used a maximum daily rainfall intensity to simulate the Muer landslide stability changing rules in the rainfall process. Landslide stability safety coefficient with rainfall duration reduce. Safety coefficient after rainfall has stopped will be a lag phenomenon, when the rain stopped for a period of time to reach the minimum safety coefficient, then began to rise.4. In 7,8,9 magnitude of three different earthquake intensity, this article considered the deformation characteristics and stability of Muer landslide. Summarized that:(1) With the increase of seismic intensity, the landslide displacement, maximum shear strain are increases.(2) The excess pore water pressure under the action of earthquake will rise sharply in a short time. Its value will decreased with the increase of elevation.(3) With the increase of seismic intensity, the stability is decreases and the less than the critical value is also more and more frequently.5. This article considered rainfall infiltration and earthquake force to analysis under different earthquake intensity and different rainfall intensity the deformation characteristics and stability of Muer landslide.(!) Under the same condition of seismic intensity, this paper study three kinds of rainfall intensity (20mm/d、40mm/d、60mm/d) to analysis of rainfall intensity affect on the deformation and stability of the landslide. With the increase of rainfall intensity, Landslide displacement, maximum shear strain, on the x, y direction are gradually increased. The landslide stability safety coefficient are decreases, less than the critical value number are increase.(2) Under the same rainfall intensity, this article have selected 7,8,9 of different earthquake magnitude to discuss seismic dynamic effect on the deformation and stability of Muer landslide.With the increaseing of earthquake magnitude, the displacement and maximum shear strain have a substantial increase, less than a threshold number are increase. |
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