Study on Cyclic Bearing Behavior of Pile in Sand (Ii)(2/2)

This study is a three-year project. Its purpose is to investigate and quantify the effects of cyclic loads on the lateral and axial bearing behavior of a pile using model pile load tests. The non-linear analysis models of single pile and pile group will be established based the test results. Using the above models, non-linear pushover analysis will be performed on two real cases to explore the influences of cyclic loads on the design solution of piled foundation. The proposed analysis model and procedure for cyclic loads will be a useful guide to the practices of earthquake and ocean engineering. The first year project (under execution currently) is to design and assembly a set of equipments for performing model pile load tests under cyclic lateral loads. The equipments include loading and reaction system, instrumented model pile, control and measuring system, and model ground preparing device. This study will use Chunan sand to prepare the model ground by a mobile pluviator. Three sets of static ultimate lateral pile load tests will be carried out first in the model grounds with three kinds of relative densities. Then, nine sets of one-way cyclic lateral pile load tests will be performed by considering different density and stress level of cyclic load. Finally, on the same conditions of density and stress level, nine sets of two-way cyclic lateral pile load tests are going to be finished. The p-y curves of Chunan sand will then be deduced from the test results for static and cyclic loads. In the second year (application in this year), the pile load test equipment will be modified into a pile load test equipment for performing cyclic axial loads by changing the loading and reaction system. Three sets of static ultimate axial pile load tests will be carried out first in the model grounds with three kinds of relative densities. Then, nine sets of one-way cyclic axial pile load tests will be performed by considering different density and stress level of cyclic load. Finally, on the same conditions of density and stress level, nine sets of two-way cyclic axial pile load tests are going to be finished. The t-z and q-z curves of Chunan sand will be deduced from the test results for static and cyclic loads. In the last year (application in this year), the p-y, t-z, and q-z curves from international standards and this study, as well as the curves of plastic hinges of different piles will be coded into an analysis module using EXCEL software. Non-linear models (both pile and ground are non-linear) of single pile and pile group will be established using SAP2000 software by integrating the results of EXCEL module into the input interface of SAP2000. The pushover analysis of the nonlinear models will be performed on two real cases to evaluate the effects of cyclic loads on the design solution of piled foundation. Finally a nonlinear analysis model and procedure for piled foundation under cyclic loads will be proposed for the use in the engineering practice.