Seepage And Stability Analysis Of Artificial Landscape Hill Slope Under The Condition Of Rainfall

With the development of urban construction, a large number of abandoned soil and solid waste produced from the demolition of urban transformation, river dredging and the project of mines. It is the hot spot of current research to discuss the way to deal with the abandoned soil and solid waste. In recent years, the project of artificial landscape hill, which is different from the natural mountain, solved this problem effectively. So it has the important significance to study the permeability and expansion of the soil-rock mixture used as the slope material, and the seepage field of the artificial landscape hill under the condition of rainfall. Xiashu soil in Nanjing area is used as the fine grained soil, then mixed with 0,15,30 and 45% breccia with irregular shapes respectively. A series of permeability and expansion tests are performed under controlled dry density conditions. In this study, a new type of instrument is designed to measure the permeability and expansion of soil-rock mixture. In the meantime, use the module of seepage analysis and slope stability analysis from the Geo-Studio to research the dynamic changes of the slope seepage field on the different condition of rainfall. And combined the seepage calculated result of finite element, the dynamic variation of slope stability under different conditions of rainfall is analyzed by limit equilibrium method.Several research results were made by the paper as follows:(1) This thesis presents a design and study of a new type of instrument to measure the permeability and expansion of soil-rock mixture quickly and conveniently in engineering site, which can also meet the requirements of sample size.(2)The results show that inclusion of rock in soils can significantly increase the permeability of soil-rock mixture, which increases exponentially with increasing rock content (k=k0enp). The expansion of mixture decreases linearly with increasing rock content. The permeation rate of soil-rock mixture decreases with increasing density, and the expansion increases with increasing density. There is an obvious linear relationship between the expansion and the moisture content. Compared with the results of saturated permeability by flexible wall permeameter, it can be found that the permeability of mixture measured by two instruments have the same rules. However, there is nearly an order of magnitude between them.(3) The transient saturated zone within a certain range will be formed in the slope of artificial landscape hill surface during the rainfall process. The formation and development process of the transient saturated zone and the volumetric water content in the slope are closely related to rainfall time and rainfall intensity.(4) The calculating results show that the soil on the surface of slope is mainly affected under rainfall. The pore water pressure of the surface soil will increase with the rainfall duration increased until it reaches zero. In the process of the rainfall, the negative pore water pressure at the foot of the slope will go to zero first, which have an important impact on the slope stability. So we should pay more attention in the design and management.(5) The safety factor of artificial landscape hill will decline in different degrees as the increase of intensity and duration of rainfall. And the minimum safety factor will not be appeared at the instant of rain stopped, but there is a certain lag.