Nonlinear Least Squares Method for the Testing of Pile Integrity
Zhang Canhui(1),Zhang Jianlin(1),Xie Jianhua(2)
(1 The Civil Engineering Department of Xiamen University, Xiamen, 361005, China)
(2 The Construction Safety and Quality Supervision Station of Xiamen, Xiamen, 361000, China)

Abstract: The reflected wave method is simple and audiovisual, which has come in to common use in the testing of pile integrity, but it is difficult to solve the stress wave attennation by the absorption and scattering of pile and soil. The reflected wave equation including the attennation factor of pile and soil and the reflecting factors of discontinuity interface, is transformed into the nonline ar least square description, the trust region method is suggested to deal with. The Gauss-Newton direction is used to define the two-dimensional subspace of the trust region to accelerate the convergence. The example for real pile verifys the effectiveness of this method.
Keyword: testing of pile integrity, nonlinear least square problem, trust region method.