Print Email Facebook Twitter Calculation of dynamic pile bearing capacity based on the displacement during driving Title Calculation of dynamic pile bearing capacity based on the displacement during driving Author Christophe, J.J.B. Contributor van Tol, A.F. (mentor) Everts, H.J. (mentor) Holscher, P. (mentor) Van Koten, H. (mentor) Vijlbrief, M. (mentor) Faculty Civil Engineering and Geosciences Department Geoscience & Engineering Programme Geo-engineering Date 2014-01-09 Abstract The static bearing capacity of most driven piles in The Netherlands is derived using a preinstallation method based on soil parameters. As a result of recent research the reliability of this method decreases; As a result different calculations might become attractive. A method widely used abroad is a Dynamic Load Test(DLT) to calculate the dynamic resistance during driving, and to convert this to static resistance. Literature study reveals little research is available concerning the conversion from dynamic resistance during driving to final static bearing resistance. In this research the COLOMET (COntactLess Optical MEasurement Technique) is investigated to determine the dynamic resistance during driving based on displacement during driving. In order to measure the displacement a laser is suspended on a beam and measures the displacement of a angular profile attached to the pile. Due to the length of the beam and the application of an accelerometer the disturbance of the sensor can be eliminated. The measurement technique is proven to be successful, however the attachment of the angular profile to the pile requires improvement. A Linear Elastic Perfectly Plastic(LEPP) soil model is used; All force exceeding the ultimate soil resistance Fy will result in plastic deformation. Since no more soil resistance is present after exceeding Fy a ’free rod’ model can be used. Force can be converted to velocity when dividing by the impedance Z, a material constant.If the velocity corresponding with the ultimate soil resistance, vy, is subtracted from the total velocity and integrated over the time plastic deformation occurs this will result in half of plastic displacement. With only Fy as unknown this value can iteratively be changed until the calculated plastic displacement converges with the measured plastic displacement. A validation is performed with another ’established’ method, the DLT. However due to physical differences encountered during driving in combination with the different calculation methods it is concluded the performed measurements are not suitable for comparison. The assumed LEPP model is also a simplification of reality and should be investigated when the method is applied. The time-intervals for integration are dependent of the value of vy and are not 1D-wave-equation related. The COLOMET applies a combined resistance at the toe. This only is valid if no shaft resistance is present since superposition of shaft resistance is not possible. Further research is advised concerning the possible separation of toe and shaft resistance. In order to do this experiments are advised with multiple strain-gauges. A FEM model should be constructed to verify the model, this however requires a physical test to be validated. The assumed force equilibrium at the toe and the corresponding ’free rod’ model requires further investigation since the validity of this assumption is insufficiently proven. Subject soil dynamicsdriven pilesbearing capacity prediction To reference this document use: http://resolver.tudelft.nl/uuid:b7fbcefc-d9be-4383-bca4-28e2a310dd0a Part of collection Student theses Document type master thesis Rights (c) 2014 Christophe, J.J.B. Files PDF Jeroen_Christophe_FINAL_V ... riving.pdf 20.64 MB Close viewer /islandora/object/uuid:b7fbcefc-d9be-4383-bca4-28e2a310dd0a/datastream/OBJ/view