Mechanical Mechanism For Deformation Of Steep Rock Slopes With Anti Dip And Early Identification Methods

Over the vast areas surrounding Qinghai-Tibet Plateau of China, deep valley develops, the slope of topography is steep, Complex regional geological tectonic develops and the earthquake is frequent; High and steep slope and Engineering Slope are the main area which generate Large geological disasters and massive damage of Engineering Slope, On the regions where sedimentary rocks or layered rocks are widely distributed, especially, problems of damage of bank slope toppling rock mass and disaster’s inoculation、formation are more serious, such as slope of Huangdeng hydropower station, slope of Miaowei hydropower station. In recent years, The great importance is attracted to the research of dumping body at home and abroad, but little systematic research is formed for damage to dump slope. In this paper, based on the national key basic research development plan (973) project of the western mountains of large landslide hazard-formative factors identification, precursor method of access to information and early warning research, To toppling deformation damage formation mechanism and its early recognition as the research subject, On the basis of the domestic and foreign research status and extensive collection predecessors’ research data, it is analyzed the toppling of the formation and breeding conditions of deformation and failure. At the same time, taking several typical slope as an example, it has carried on the system induction and summary bout the deformation of the geological characteristics, the types of slope body structure and buckling failure mode and so on. On the basis of a large number of instances, toppling deformation damage mechanics model is established, and from the point of view of mechanics, toppling of deformation and failure process are analyzed. Meanwhile, combining with a large number of typical slope as an example, taking the engineering geology, mathematical statistics, numerical simulation and so on many kinds of theories and methods, the index system of early identification of toppling slope deformation and destruction is established, and it is come to implement the early identification of dumping of the slooe deformation. Finallv, this paper puts into use of the fuzzv mathematics comprehensive evaluation to the stability of the slope deformation and destruction. The research made the following achievements:(1) According to analyzing the geological survey and the deformation and failure characteristics of typical example, cause and control conditions of the slope toppling deformation failure that are summed up have the following features:① High and steep slope, average slope:> 40 degrees,② slope body is made by a thin-thick bedded slate, carbonaceous slate, phyllite, sericite schist, or by the thin-thick sandstone layers, specially, by plate cracking granite or block crack of igneous rock, etc.③The layer rock has steep dip Angle, generally greater than 50-65°. ④The slope has a weak base. Under the combination of the geological structure, the falling of slope deformation mainly has four kinds of Failure modes-the block toppling, the compressed toppling, the shallow toppling, the deep toppling.(2) The toppling of the deformation of slope geological generalized model is established, meanwhile, the toppling of deformation produced by the driving force and the deformation and failure process are analyzed. In this paper, it is put forward the concept of produce toppled slope deformation which needs critical height. Combining with modern mechanics, the critical height of toppling slope deformation is deduced this formula: Critical height H1=cos(α+β-θ)/h1sinαsin(β-θ); Critical height H2-cos(α+β-θ)/(h1+h2)sinαsin(β-θ) Critical height H3=cos(α+β-θ)/(h1+h2+h3)sinαsin(β-θ);(3) In combination with a large number of typical examples and mechanics analysis, the toppling slope deformation is established early recognition system. This system selects the main control factors (thickness of strata, dip Angle strata, slope height, slope Angle, lithologic combination, structure of rock mass) and appeared factors (slope crack, the slope berm, fracture surface), in total of eight identification index. And for the main control factors, UDEC numerical simulation is adopted to analyze quantitative index of the state value. In combination the statistics theory with the theoretical analysis, the influence degree of the qualitative index to toppling deformation is discussed in this paper, and early recognition quantization table of toppling deformation slope stability is obtained.(4) Based on the concept that the slope deformation and failure mode always depend on the combination of the geological structure characteristics, in this paper, the fuzzy mathematics comprehensive evaluation method is introduced. In view of the main control factors, the membership function of evaluation factors are established, and the weight of each evaluation index values are got, A={0.3184,0.2465,0.3758, 0.2355,0.4320,0.6740}.