Pile Negative Friction Calculated

This article describe different methods of determining single piles negative friction. The advantage and disadvantage of these methods are discussed. So it is necessary for us to research simple model to determine negative friction.The factors that cause negative friction are discussed. The mechanism of negative friction and the methods decreasing it are also studied. The neutral point and negative friction are determined according technical code for building pile foundation. Load transferring concept, the author puts up with a new method which uses double broken line model to calculate negative friction. The author utilizes double broken line model to show relation between friction and displacement around the pile. The article establishes equation about friction and displacement according to elastic or plastic condition that soil around or in the tip of the pile lies in.If the soil around the pile includes several layers, we suppose each layer is well distributed. And we build equation for each layer. Then we get all equation together. Using continuous and border conditions of each layer, the negative friction will be attained. The character of soil which is around and in the tip of the pile varied greatly. We must select different hardening or soft model.Combined with the two actual projects, the author tests the precision of the method. The example prove that it is accepted, so this way can be tried to use in the actual project.