Research On Selection Theory And Method Of Sliding Plane Mechanics Parameters Of Rock Slope

The variation rules and selection method of mechanics parameters of rock slope are important in the stability analysis and slope design. The current selection of mechanics parameters of slope only presents the testing data or results of counter-analysis, often ignoring the geological state and failure model of slope. Thus the mechanic parameters of slope must be selected on the basis of deformation and failure characters of each sliding plane in order to obtain the actual state of slope and to direct the stability analysis and design of slope. The main aims and conclusions of this thesis are as follows:(1) State the research subject, focus and significance of selection theory and methods of sliding plane mechanics parameters of slope; review briefly the classification of sliding plane, strength selection of structural plane, selection method by testing and counter analysis of strength in the literature; and introduce the main parts of this thesis, relating to the problems of existing research.(2) Analyze the failure models of rock slope, and then classify the sliding plane, the sliding plane can be divided into self-born sliding plane, appendiculate sliding plane and mixed sliding plane, furtherly summarize the selection method of mechanics parameters to each types. Based on the classification, the author establishes the mechanics model of each sliding plane. Discuss the influence of water and weathering and sedimentation conditions on rock slope, and then specify the geological cause of rock bedding slope, counter-tilt rock slope and cracked rock slope.(3) Introduce the cohesion-friction model of rock strength theory, and extend the model to select the strength of sliding plane, discuss the variation rules of peak strength and residual strength under different normal stress, and then present the selection model of shearing strength. After the result of cohesion-friction model is compared with Coulomb Criterion, it is found that when the results of shearing strength are many and adjacent the strength parameters can not be regressed by least square method, instead the results should be divided into some beelines at that time according to the cohesion-friction model.(4) Discuss the characters of hard structural plane and weak structural plane: The adhesive friction theory is applied to research the changing course of shear area of hard structural plane and its influence on shear stress. The shearing failure of structural plane is considered to be corresponding to the maximum of real contact area, a criterion is given to distinguish the shearing failure of structural plane and a new select method of shear strength is brought forward subsequently; Examine the influence of geometrical features and thickness of weak intercalation on the integrative strength of weak structural plane based on the composing of basic strengths, formative mechanism of shearing plane and failure pattern; and present the quantitative relation between the strength and thickness.(5) Discuss the counter-analysis method of strength of sliding plane; point out some problems of imbalance thrust force method; introduce the elements and operation of slice-stability method; and present the selection gist of strength in counter analysis by slice-stability method. The strength of slopes along the Hurong Highway in Hubei province are respectively obtained by imbalance thrust force method and slice-stability method, with the result showing that the mechanics conception of slice-stability method is clearer and much easier to operate.(6) Discuss the forming conditions, evolution process and the method to obtain strength of toppling-sliding plane. Based on the forming course the fore-toppling state and post-toppling state are selected, and the factor of safety and its corresponding strength of the two states are presented, then the two variables equations about the parameter of sliding plane are established by Sarma's method, and the parameter of slip plane c andφcan be obtained by solving the equations.