Field Lateral Load Tests And Analysis Method Of Flexible Large-Diameter Rock-Socketed Pile

In order to fully understand the properties of pile-soil interaction of lateral loaded pile under large deflection and to improve the theoretical design methods for lateral loaded pile, a field test on two lateral loaded large-diameter rock-socketed steel pipe piles, which are part of a coal wharf structure, is presented in this paper. Base on this test, various theoretical approaches, such as "m" method, composite stiffness principle with biparameter method, "NL" method, are used to analyze the behavior of piles subjected to lateral load. Furthermore, the determination of soil parameters of various approaches under large deflection is demonstrated particularly in this paper. Thus some valuable results about the properties of lateral loaded large-diameter pile can be obtained. Base on the former research, the main works of this paper are mainly showed below:1. Field test on two flexible large-diameter rock-socketed steel pipe piles under lateral load is introduced. And the test results is arranged and analyzed for further research.2. On the basis of field test, the "m" method is used to analyze the behavior of pile-soil interaction of two test piles under lateral load, which can reach a conclusion that the "m" values suggested in specification can not be used in the case of large deflection. At the same time, the sensitivity analysis of parameter "m" is presented. Then, a new nonlinear "m" method based on model test is introduced, in which the popular constant "m" value is related with pile head deflection by power function, and this relationship is described by two factors: b_m and k. Furthermore, this new method is modified by the author to make it suit to the calculation of full-scale test piles under large deflection.3. Recently developed methods, such as composite stiffness principle with biparameter method and "NL" method, are used to analyze the field test results of the two large-diameter piles. Thus, the pile-soil parameters are accumulated for these methods. At the same time, in order to determinate the horizontal coefficient of subsoil reaction k_N values in sandy soil, the regularity of k_N is presented. These regulations include the relation between k_N and horizontal force H, as well as the relation between Bk_N and measured stiffness of pile top K.4. By comparing the three methods mentioned above, the applicability of these methods is discussed. And even how to determinate the design soil parameters for large-diameter pile under large deflection is demonstrated.