Deducing Pile Responses from Inclinometer Data of a Lateral Load Test
Date Issued
2007
Date
2007
Author(s)
Chen, Yu-Chun
DOI
zh-TW
Abstract
Abstract
In a laterally loaded pile test, the pile deflection is usually measured by using a buried slope inclinometer. The deflection of the pile can be obtained by integrating the data of measured slopes. To deduce the internal forces of the pile and associated soil reactions on the pile, the elastic beam theory is usually applied in engineering practices. The procedure firstly adopts a smooth curve function to fit the slope or deflection data of the test pile. Then, on the basis of the fitted function, the bending moments, shear forces, and soil reactions along the pile can theoretically be deduced from the beam theory by successive differentiations.
Since many differentiations may amplify measurement errors and when a pile moves into nonlinear response the pile internal forces and soil reactions obtained by differentiating the slope or deflection of the pile are incorrect, the above procedure sometimes leads poor results. To solve this problem, Chiou and Chen (2000) developed a model that can effectively reduce orders of differentiation and consider the nonlinear behavior of the pile by using a composite moment function to do regression analysis with inclinometer slope data, instead of directly using a slope function to fit the inclinometer slope data. The composite function consists of upper and lower parts: the upper part of the pile where the response exhibits large variations is modeled by a seventh-degree polynomial and the lower part of the pile where response is small is modeled by the characteristic function of an elastic solution of a semi-infinite pile
In order to increase effectiveness of Chiou and Chen’s model, this study further simplifies their model by using a fifth-degree polynomial to model the moment distribution of the upper part of the pile. For verification, both the solution of finite element analyses and the results of in-situ load tests have been adopted and the results of regressive analyses can satisfactorily obtain the pile responses. In addition, on the basis of curves of pile deflection and soil reaction deduced from the results of the pile test, a set of site-specific p-y curves can thus be established. Finally, a sensitivity study has shown that accurate estimate of moment-curvature relationship of a pile is essential to the accuracy of the deduced pile internal forces, soil reactions, and p-y curves.
Key Words: lateral pile, lateral pile test, inclinometer data, p-y curve, regressive model.
Subjects
側向樁
基樁側向載重試驗
傾度管資料
p-y曲線
回歸分析模式
lateral pile
lateral pile test
inclinometer data
p-y curve
regressive model
Type
thesis
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