A Study of the Occurrence Mechanism, the Prediction and Prevention Works of Landslides by the Groundwater Flow Analysis

(1)由于潜水潜势最大的地下水通过孔壁入渗并垂直扩散，形成了具有屏蔽断面的观测孔内水质的垂向分布。通过数值分析和砂土模型试验，得到了如下结论：在滑坡坡面这样的倾斜地下水流中，沿其全长具有遮挡断面的观测孔的水位与地下水原始自由面以下的水位不一致。(3)提出了一种分析具有自由面的稳定地下水流的简单有限元方法。该方法适用于非饱和带内的所有区域，在非饱和带内渗透系数不变的情况下，无需网格迭代。该方法可以很容易地应用于涉及复杂边界和任意程度非均质性的各种问题。在稳定性分析中，地下水压力的垂向分布不能假定为具有倾斜的无压渗流、具有多个不同渗透率的S、丘陵等不同透水性的滑坡。

(1) The vertical distribution of water quality in the observation borehole with a screened section along all its length is generated as the results that the groundwater having the highest potential infiltrates into the borehole through its wall and diffuses vertically. And therefore the distribution of water quality in the borehole disagrees with one of groundwater being adjacent to the borehole.(2) We obtained the following findings from the numerical analysis and the sand model experiments : In such inclined groundflow as one in landslide slopes the water level in the observation borehole having a screened section along all its length disagrees with but appears below the original free surface of groundwater.(3) A simple finite elements method analyzing steady groundwater flow with a free surface is proposed. This method is applied to all the region involving the unsaturated zone without mesh iteration under the condition of which the hydraulic conductivity is constant in the unsaturated zone. The method can be applied with ease to a wide variety of problems involving complex boundaries and arbitrary degrees of heterogenity. Owing to this method it will be very easier to obtain the pore water pressure along the slip surface which is necessary to the stability analysis of landslide slopes.(4) In the stability analysis the vertical distribution of the ground water pressure should not be assumed static in the landslide slopes which have inclined unconfined groundwater flow and which have -the multi-s, Lratums with different permeabilities.