Evaluation of three dimensional vertical and lateral bearing capacities of pile foundations using X-ray CT

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The objective of this research is to evaluate both vertical and lateral bearing capacities of pile foundations using X-ray CT scanner. The contents of these two topics are summarized separately as follows :(1)Vertical bearing capacityThere are several types of failure patterns such as those proposed by Terzaghi, Meyerhof and Vesic. But those have been proposed for the purpose of design calculation and are not based on close observation of real behavior. The objective of this research is to visualize and to characterize the failure patterns of the ground under vertically loaded pile foundation using X-ray CT scanner. Here, a series of model loading tests with different conditions such as shape of pile tip, effect of loading process, soil density and loading speed were conducted and the model ground was scanned in each case. Finally, the bearing capacity mechanism due to vertically loaded pile was visualized and evaluated in three dimensions without any destruction for the first time and … More it is convinced that X-ray CT is one of powerful tool in geotechnical engineering.(2)Lateral bearing capacityThe objective of this research is to investigate three dimensional(3-D) failure patterns in sand due to laterally loaded pile using X-ray CT. Here, a new apparatus of model loading test especially for X-ray CT was developed and a series of model loading tests were conducted using this apparatus. Then, CT scanning was done for the model ground at several levels of loadings which were applied at the pile head. Not only cross sectional images for the ground but also those in 3-D were reconstructed. Here, a proper image processing analysis was conducted in order to obtain effective CT images. And, the failure patterns of the ground under laterally loaded pile were visualized without any destruction in three dimensions. Quantitative discussion was also examined. Finally, it is convinced that three dimensional failure patterns of the ground due to laterally loaded pile were visualized for the first time using X-ray CT. Less