| In China, the distribution of karst is quite extensive. In the construction of national economy, with the rapid development of transportation construction, the distribution of karst brings a great deal of influence on design and construction of bridge pile foundation in karst areas. Therefore, a systematic study on the construction of the bridge pile foundation in karst areas has very important practical significance.In this thesis, the author makes an analysis on stability of bridge pile foundation in karst areas by adopting Elasticity theory. Also, there is a study on stability covering the surface of karst through the use of limit equilibrium theory. Accordingly, this thesis summarizes several common factors restricting the stability of the pile, and concludes the safety factor formula of the free face covering the karst under the influence of foundation piles. At the same time, through the research of engineering examples, this thesis analyzes recurring problems, causes, prevention measures and processing methods etc. in the process of constructing bridge pile foundation in karst areas, and obtains suitable approaches to construct bridge pile foundation in karst areas, namely hand-dug pile, drill hole filling pile and the impact into hole filling pile etc. And there are specific measures such as artificial digging pile, steel casing bearing close impermeable layer, throwing clay blocks and stone tablets, drill properly installed, the increment of guide frame and reasonable penetration control. Based on analysis of selection constraints of bridge foundation drawn into hole in karst region, this thesis concludes selection of constructing pile into the hole in face of various karst forms.The research results of this thesis provide a beneficial reference for selection of methods in constructing bridge pile foundation, quality control and formulation of the construction procedures in karst areas. |
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