The Application Of Genetic Algorithm In The Assessment Of Slope Stability

A large scale of highway construction is booming in our whole country. During the course of design and construction of highway, for the purpose of length, turning radius and longitudinal gradient, we have to construct a lot of high slope engineerings. So the slip of roadbed's slope often happen. Roadbed is the foundation of road surface, together with road surface roadbed endures the loads, thus the roadbed's intensity, stability, etc. affect the using capability of road. The question of slope's stability of roadbed has stirred people's attention.The technology of the protection for roadbed is very poor so far. Before the middle of 1980s our country's highway construction focused on low-end highway, so the safety engineering is not very important. Just from 1990s, our country has been focuseing on the construction of top grade highway, because of scarcity for safety research, so only used the technology for low-end highway's reinforce and referenced technology for other vocation. So there are a lot of hidden troubles.The stability design for the slope of roadbed is very important. Whether fit or not of design for slope determines the slope's stability. During the course of design, it must be based on highway's rate, rain's intensity, groundwater, landform, soil, materials, etc. So adjusting measures to local conditions for the technology selection is very important for the safety of vehicles. This paper reviewed the history of slope stability analysis, compared all the methods used for slope stability analysis, and analyzed the shortcomings of the methods used for searching the failure surface, for reasons of a lot of uncertainties, for example random uncertainty and fuzzy uncertainty, are existed in the slope engineering. Traditional methods can't resolve complex questions. So the new design and methodology are suggested in terms of GA's principle, these are just this paper's object. The main achievements are as followings.1. A unified optimization model of slope stability analysis is obtained, and the model's structure and the form of limit state equation do not vary with the analysis methods of slope stability.2. For circle failure surface, this paper uses GA's theory to search the center of a circle and the radius of it separately, and based on simple Bishop method to compute the safety factor ( F ), and compiled program successfully. This method can be used for all kind of slope with regardless of slope's shape, boundary condition, and etc. This method can be used for slope stability analysis and the design of slope.3. Based on the assumption of general slip surface, a general formula of safety factor of slope is presented in which the forces exerted on the slices exactly satisfy theequilibrium condition. Using the method the chapters introduced to search critical slip surface, and proved by examples, this method is more reliable, and can search , simulate the critical slip curve. Compared with traditional methods this method demands less condition. If data file can be setup correctly it can search the critical slip curve successfully. As the method in chapter 4, this method also can be used for slope stability analysis and the design of slope.