A Study On Jointed Rock Slope Stability Analysis Using Meshless Method

This paper uses the meshless methods and fracture mechanics to analyze the rockslope stability and studies on the how the existence and arrangements of static facturesand joints influence the overall slope stability. Firstly, a study is made on the theory andalgorithm of meshless methods and fracture mechanics. Secondly, the slope stabilityappraisal method based on meshless analysis is presented. The author uses C++ languageto realize the above content and uses the program to calculate some examples. Theseexamples comprises the basic quantitive verification of the program and some rockslopes with different combination of joints varying in number and cut-through ratio. Theinfluence of cut-through ration, position and combination form of joints on slope failuremode is discussed.The meshless analysis provides the sliding zone of rock slope in form ofdisplacement and stress field. However, the safety factor which is widely accepted infield of engineering is not gained. To address this problem, the author used the circularmethod, polygon method and graph theory to search the sliding surface and calculate thesafety factor. The sliding surface searched can serve as a proof of the validity of themethod and program analyzing the rock slope, i.e. to judge if the searched sliding surfaceconforms with that given by displacement and stress field. Engineers commonly computesafety factors by empirically selecting one structural plane or several controllingstructural planes in combination to get the sliding surface and this method is generallyeffective in simple structural plane case. However, in case of complicated jointscombination, we could hardly give direct judgement on which combination is thecontrolling one. The circular method, polygon method and graph theory could search thesliding surface of joint combination with minimum resisting forces.Finally, the paper puts up some key topics in rock slope stability analysis usingmeshless methods and some problems in applying fracture mechanics in rock massanalysis. Further research based on this paper and problems met in this study arepresented.In conclusion, the author's work can be reduced to the following:1. A systematic introduction and comparison are made on current rock slopestability analysis theories and methods from tow parts, namely, the analytical method andnumerical methods. The analytical method includes the limit equilibrium method andplastic limit analysis and the numerical methods are mainly composed tow categories, namely, continuum and non continuum methods. The advantages and drawbacks of thesemethods are compared and the connection of the upper and lower limit of them arediscussed.2. The advances on current jointed rock mass analysis method are introduced mainlyon computation methods of FEM and meshless methods in joints analyzing, fracturemechanics simulation of joints and fractures and the closing and frictional rules of joints3. The rock slope stability analysis and realization techniques are described. Thenode arrangements along joints and tip nodes enriching algorithm, the shape functioncalculation using visibility criterion, the calculation of SIF K_â… and K_â…¡using contourintegral method are presented. The circular method, polygonal method and graph theoryare introduces into rock slope stability analysis to get the overall safety factor. Thegraphing constructing method utilizing the nodes of meshless analysis is discussed.4. Some rock slopes with different combination of joints varying in number andcut-through ratio, The influence of cut-through ration, position and combination form ofjoints on slope failure mode is discussed.5. The meshless rock slope stability analysis is realized using C++. And the keytechniques are in the following:(1) The algorithm and program of intensified node arrangement near crack tip andalong crack line(2) The shape function calculation of point near crack based on visibility criteria(3) The contour integral method for calculation of stress intensify factor K_â… K_â…¡(4) The rock slope appraisal method using circular method, polygonal method orgraph theory method depending on the slope joints combination...