| Northwest China since the Quaternary climate change, a lot of loess deposited on the surface, forming a unique topography. Mainly in the area of Loess hilly landform, different provinces due to the different mechanical properties of loess are not the same climatic conditions, due to the loess with large pores, reduce water intensity and other characteristics of the Loess Plateau often landslides, mudslides and other natural occurrence disasters, geological disasters is one of the areas of domestic and even the world’s most-prone. Landslide as a common geological disasters, whether natural formation of landslides, or in construction projects due to the instability caused by the excavation slope engineering, slope stability issue has been one of the issues of most concern engineering geology. Many scholars have done a lot of loess slope problem-depth research, analysis from mechanics, loess microstructure consisting slip angle with soil characteristics studied loess slope instability reasons, but as a special loess soil, water mechanical strength resulting in reduced properties compared to other rock body more sensitive to water. Loess - mudstone slope due to the contact layer impermeable shale constitute such impermeable layer is formed at the junction of rock and soil, resulting in loess mechanical index near the contact face serious decline, easy to form a slope failure. Lin Ping Station is the slope after slope railway construction excavation cause instability example of loess - mudstone contact slope, loess and mudstone belong to two since the mechanical properties of the dielectric body varied widely, the slope is a non-material composition homogeneous body and by the weak level control, the commonly used two-dimensional stability analysis and finite element analysis is difficult to consider the impact of the strength of the contact surface on slope stability, characteristic for this type of slope, paper selects three-dimensional limit equilibrium method, the the method can be imparted to the slide surface strength parameters to calculate stability, thereby taking into account the effect of the contact surface of the weak interlayer stability in the calculation, you can get more accurate results.Now the main use of slope stability calculation is based on Moore - dimensional limit equilibrium slope stability criteria and static Coulomb force balance principle under analysis calculation, calculation program in this area has a lot, a lot of applied engineering practice. However, slope stability as a special issue of having a three-dimensional space, a simple question slope consider a two-dimensional planar computing problems, ignoring the lateral stress, resulting in large and medium slope calculation, due to the formation complexity and change undulating terrain, often lateral stress is not simply ignored. Predecessors also took note of this, so many scholars have proposed different methods to calculate the three-dimensional analysis of slope stability. More mature three-dimensional finite element method and finite difference method, there are many commercial software has support, but this is not a continuous medium slope calculations, these two methods are difficult to obtain accurate results, as the loess-mudstone contacts type surface slope, should be the main object of study the mechanical properties of the contact surface, the experiment is difficult to achieve in the face of strength parameters, the algorithm also meet anti-computing needs. Three-dimensional limit equilibrium method predecessors have achieved a lot, there are three main theories mature Bishop method, three-dimensional Janbu method, three-dimensional Fellenious method, three-dimensional Spencer method. However, due to the complexity of the program it has not been compiled into a three-dimensional computer program commercial software, so I’m Ping according to the characteristics required slope, self dimensional stability calculation program to calculate the stability of the slope, made a very good results. |
