The Reliability Study Of Soil Cutting Slope Based On The Modified Sarma Method

In the civil engineering, it is a very important issue to study the stability of soil cutting slope. Traditional evaluation method of slope stability is the safety factor method. However, the safety factor obtained by this method is not accurate, beacause this method neglects the uncertainty of the soil properties parameter. In view of this shortage, coupling algorithms of Monte Carlo method and Modified Sarma method was used in this article to calculate the slope stability and to analyze the sensibility of various impact factors on slope stability, in order to supply a foundation study for the stability analysis of soil cutting slope.By analyzing the methods of documentary data、theoretical and numerical calculation, this paper studies the stability of soil cutting slope based on the reliability. The main results of this paper are below:First, the article performed a comprehensive analysis of existing document literature at home and abroad, summarized several available evaluation methods of soil cutting slope stability and analyzed their advantages and disadvantages.Second, the various factors affecting the stability of soil cutting slope were studied. It’s mainly about the computing methods of ground water and water table’s mechanical effect. Comparing with the other limit equilibrium methods, Sarma method is more advanced,because it has less basic assumptions, more rigorous derivation process of mathematical models and its mechanical model is closer to actual.Third, the methods of slope reliability analysis were explored and their advantages and disadvantages were analyzed. The analysis showed that the reliability value of slope by Monte Carlo method has higher precision, and it is easily fulfilled in micro-computers. So, in this article Monte Carlo method was chosen as the reliability analysis of slope.Fourthly, Monte Carlo method and modified Sarma method were discussed in this part. The computer programs to calculate the stability coefficient by Modified Sarma method and to calculate the slope reliability by coupling algorithms of Monte Carlo method and Modified Sarma method were crafted. Finally, based on the actual example in the project, the computer programs of slope reliability crafted in this topic was used to analyse the sensitivity of impact factors on slope stability and the influence of variable coefficients on reliability indexes. Studies show that earthquake, drainage percent, cohesion of bottom sliding surface(c) and angle of internal friction(Φ) were sensitivity factors. The variability of shear strength value(c and Φ) of soil has a major impact on the slope reliability index.