Research On Lower Bound Method Of Plastic Limit Analysis For Rock Slope And Rock Bridge

Slope stability analysis is an important branch of the geotechnical engineering. With the rapid development of economy in our country, more and more transportation Engineering、water conservancy and Hydropower Engineering、energy engineering and other important projects are carried out in the mid-south and southwest. It is certain to have a large number of rock slope engineering problems in the process of the construction of these projects, which not only seriously affects the process of the project, but also the people’s lives and property and the development of the national economy. So it is very important to study the stability of the slope. The reasecher is supported by the National Natural Science Foundation, which name is:Reseach on The Plastic Limit Analysis Method for Toppling Failure of Layered Rock Slopes (51564026). The main research contents of this paper are:(1) The reseach significance of stability of rock slope with rock bridge is clarified. The analysis methods of slope stability are detailed summarized. And the development and research status of plastic limit analysis at home and abroad are introduced. The present research situation of the rock bridge damage is also introduced in this paper.(2) This paper introduces the basic theory of plastic limit analysis method and limit state, the proof and inference of theorem of the upper or lower bound method of the plastic limit analysis is also introduced.(3)Put forward a new kind of Slice method to calculate the Slope stability. The nonlinear mathematical programming model of slope stability analysis is established through combining with the bottom of the market principle, the balance equation of sliding surface yield condition, the yield condition of contact area between constraints and so on, which uses slider as the research object and takes safety factor of slope stability as the objective function. Then this method is used to calculate the security coefficient of selected soil slope example and three multi-slider rock slope examples. The calculating results are compared with those worked out by the rigid limit equilibrium method (GeoStudio) and the finite difference method (FLAC3D).(4) A plastic limit analysis method of rock bridge failure analysis in rock slope is proposed. The mechanical property and the failure mechanism of rock bridges are also introduced. The rock slope with rock bridges is simulation by composite element method. The rock block is simulation by block element method. The rock bridge is distracted by triangular finite element method. And a mathematical programming model based on the lower bound method is established by combining the lower bound method of plastic limit analysis, block element discreteness technique, finite element discreteness technique and nonlinear mathematical programming. Then analyzing two examples of rock slopes, the comparisons among other results are made.(5) To summarize the main content of this paper and make the prospect.