Analysis of Tip Resistance and Load-Displacement Relationship for Drilled Shafts

• Main Authors: Jie-Cing Lin, 林杰慶
• Other Authors: YIT-JIN CHEN
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/dzh57y

碩士 === 中原大學 === 土木工程研究所 === 103 === A large number of drilled shaft load test data are applied to evaluate the load-displacement relationship and tip resistance, and these data are divided into drained and undrained soils. To analyze the ultimate bearing capacity, all collected load test data have both large displacement and load distribution curve along shaft. By statistical analysis, the typical load-displacement curve is established. Because the mobilization of tip resistance is affected by the shaft depth and soil strength, these load tests are further divided into two sub-groups for the analysis of load-displacement curve based on the shaft depth/diameter, SPT-N value, and ratio of tip resistance. With such classifications, more representative load-displacement curve can be reached. Comparing measured and predicted tip resistances of drilled shafts, it is found that the predicted tip resistance in drained soils is much larger than measured results. Therefore, the analysis coefficients used in drained soils are modified to make a consistent result for measured and predicted tip resistances. In the improvement of tip resistance, the methodology of optimization was used and the aspects of critical depth and no critical depth are considered in this study. Finally, this study suggested a new analysis equation that can better evaluate the tip resistance and be reliably applied in engineering practice.