Controlling Effects Of Loess Fissure On The Slope Deformation And Failure

Loess is not homogeneous soil, fissure is widely developed in the interior of loess mass. As a good water channel and structure surface, fracture surface has a great influence on slope deformation and destruction, especially when the fracture surface cut-through or fracture surface combined with the bedrock or the weathered zone, it will cause a directly affect on the soil stability. In this paper, the types and features of crevices in loess is studied in detail based on the past research results, and with the aid of numerical analysis software to simulate the crack growth process, on this basis, we explore the deformation and failure patterns and character of slope under the control of different types of crack. The research results can be used for prediction of slope failure under the control of different types of fractures, so as to better service for the engineering construction.The main research results are as follows:(1) There is many source of the fractures in the mass, we could classify fractures according to different standards. Crack can be divided into new crack and derivative crack based on whether the crack development is under the control of the joint. The formation of the former is not affected by joints, and it also could be divide into newborn arc crack and newborn line crack. The results give a new thought to research the evolution of slope, on the same time, provide practical examples and theoretical basis for the slope deformation and destruction.(2) This paper studies the cause of the loess fissure In-depth, and make a simulation for the growth process of loess fractures by means of numerical analysing. On this way, we have a deeply study on dynamic evolution of the fracture mechanism of evolution, and point out that the fracture evolution process of loess slope is degeneration of damage evolution process, which also shows the important role of fissure on the slope evolution.(3) Crack growth direction is not invariable, it is restricted by opening conditions, the fracture has a prone to turn when it developed to a certain depth in the vertical, the fracture surface has a relatively small angle after it turn, but it’s extent directly affects the size of the slip length. After the turn to the length of the crack is small, when the length of crevice is short after turn, collapse failure is easily happens, while the length of crevice is long, landslide is easy to occur. The evolution of the loess slope and the existence of the loess fracture are closely linked. To some extent, the secondary of slope deformation and destruction is just caused by characteristics of fracture development, which also constitutes a motivation for the slope evolution; Slope deformation and failure occurred before will constitute the loess crack growth factors and motivation. Loess crack growth is always accompanied by slope deformation and failure, the end of the slope deformation and failure also means that the disappearance of the loess fissure, in other words, the crack growth process is the process of slope deformation and failure, which show a dynamic loop.