Loess Fill Slope Stability Study

The stability of stuffing loess high slope in Phoenix Mountain shift base was studied based on its qualitative analysis, on the limiting equilibrium method and on numerical simulation. According to the study result, the control measures for this slope were suggested.Firstly, the deformation and destruction mechanism of stuffing loess high slope in Phoenix Mountain shift base were analyzed completely and deeply in qualitative analysis based on its deformation and destruction feature. The result shows that the deformation in this slope is remarkable. The fissures in the upper slope terrace and slope mass are well-development, part of this slope can see faulted phenomenon, the maximum height difference of which over 1m; the upper fissures are near the voltage transformer, and the development of them have made the pull-apparition of voltage transformer and the handrail. The deformation forms of the slope are: slope wash, collapse (slumping), mudflow, creep slide- pull apparition and collapsibility, etc. the main influence factors of deformation are: the structures and properties of filling soil, water, topography and morphology and the people's unreasonable pole up, etc. the pill soil and the water soften among of which take the leading function.Then, the stability of stuffing loess high slope in Phoenix Mountain shift base was computed by circular arc method, crack method and improved crack method, the most dangerous face was searched for by improved crack method which was optimized by composite optimal method, so, the computed time was reduced greatly, and the computed speed was increased in a great condition. The computation results was showed that: on the natural condition , this high slope is steady in whole and is limited equilibrium in the part from slope top to the slope middle; on the saturation condition, this slope is limited equilibrium in whole and destruction in the part from slope top to the slope middle.Then, the stuffing loess high slope in Phoenix Mountain shift base was numerical simulated by two-dimension limited unit and three-dimension limited difference. The result indicates that the stress field shows the features of dead-weight in total. The horizontal stress of this slope mass is press stress mainly, the shear stress is concentrated in the place of the range of 20-25 meter under the top slope. Toward the vertical stress, there have not obvious change in size and distribution, and mainly is press stress, and the greater the deeper, the smaller the backer of the slope mass. The change of vertical strain has obvious regular patterns, it is see that with the deeper of the slope mass, the vertical strain reduce firstly, the increase. It is the difference of lithology that leads to the difference character in different part. These results prove the result of limited equilibrium.Lastly, the control measures was suggested base on the qualitative analysis, quantitative analysis and numerical simulation analysis, and the study base was established reliability and theoretically.