الفهرس 
Dynamic pile load testing
NUMERICAL MODELING AND METHODOLOGYOnly 14 pages are availabe for public view
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Abstract
The use of Osterberg cell (O-cell) in axial pile load testing has been increased around the world due to the increase in construction of large diameter piles. O-cell is a sacrificial hydraulic jack(s) typically buried within the lower part of an instrumented pile to measure skin and bearing stresses.
Three case studies of full scale O-cell pile load test that have been carried out on rock socketed bored piles with diameters ranged from 1.0m to 2.50m were presented in this research. These piles were socketed in rocks with different degrees of weathering ranged from highly decomposed rock to competent rock. The related geotechnical data are described in detail in terms of: geological conditions, pile configuration, construction records, and testing procedure. The factual field data of these cases were back analyzed to interpret the skin friction, end bearing and pile load-movement behavior.
In this study, an axisymmetric finite element numerical model (FEM) was used to simulate and analyze the pile-rock interaction problem of O-cell pile load test using PLAXIS 2D finite element code.
The measured load-movement curves, unit skin friction, unit end bearing and load-transfer curves along the piles were compared with FEM simulation results revealing reasonable agreement. Afterwards, the verified numerical models were used to simulate the conventional head-down pile load test and the resulted equivalent top-down load-settlement performance curves were compared against the conventional analytical procedure to generated load-settlement curves using O-cell raw data.
A sensitivity analysis was performed using FEM to study the model sensitivity to strength parameters and to refine interpretation of rock strength parameters.
Finally, the pile load-movement behavior and the ultimate capacity components (skin friction and end bearing) derived from the verified FEM model were compared with the available national and international used norms and standards, to study the accuracy of prediction of these methods (i.e. pile behavior and ultimate capacity).