Discussion On The Method Of Stability Reliability Of Embankment Slope

Due to many factors affecting the stability of soil slope, and there are always uncertainties in these factors (physical uncertainty, statistical uncertainty, model uncertainty), the traditional deterministic analysis cannot express the safety degree of slope truly. Based on mathematical statistics and probability theory, the stability reliability theory of slope is a kind of analysis method with stochastic process and stochastic variables as research object, the biggest difference from deterministic analysis can be that considering a variety of uncertainties of slope engineering, and by controlling the more probability visual results (such as the failure probability and reliability index) to ensure the safety degree of engineering.Around analysising the stability reliability of soil embankment slope, combined with the Monte-Carlo simulation method, using SLOPE/W to compare the strategy of searching the critical slip surface, to analysis geotechnical parameters as influencing factors and to analysis factor of safety based on the variability of parameters and the target reliability, the main contents are as follows:(1) The development of the analysis method of slope stability was introduced; the method of deterministic analysis and the method of uncertainty analysis were distinguished, put forward the importance and necessity of the stability reliability analysis of slope. And the basic principles and methods of the method of reliability analysis were introduced briefly.(2) For the condition of Fs=1.25in deterministic analysis, combined with the Monte-Carlo simulation method, using SLOPE/W to analysis the stability reliability of homogeneous embankment slope. With soil parameters were under different level of variation, the difference between the results of different strategies of searching critical slip surface was discussed, and the feasibility of using SLOPE/W to analysis the stability reliability of slope was verified.(3) According to the field investigation data of railway, the stability reliability of homogeneous slope was analysised. By using method of orthogonal design, when three geotechnical parameters (density, cohesion, inner friction angel) were in level of small, middle and large variation, the influence orders to the reliability index of slope and the factor of safety was researched, got the result as c> φ> γ. With the condition of certain factor of safety, the inverse relationship of reliability index of slope and variability of paramaters was discussed.(4) Based on the definitized analysis model of slope and the definitized method of calculating factor of safety, under the condition of fixed target reliability index, the stability reliability of homogeneous slope was analysised when geotechnical parameters (cohesion and internal friction angle) were at different level of variability, got the regulation of the factor of safety with the change of target reliability index and variability of parameters. Found two kinds of factor of safety (the average factor of safety and the definite factor of safety) was proportional to the target reliability index of slope and the variability of geotechnical parameters. And in the case of certain target reliability index, with the increasing of the variability of parameters the increaseing value of average factor of safety was larger than certain factor of safety.