Analysis Of Pile Driving For Pile Foundation Of Offshore Platform

As a result of large diameter super long steel pipe piles and poor construction environment, pile installation is very difficult in the offshore platforms. Prediction of pile drivability is an essential link before pile construction. In actual projects, wave equation method is often used to analyze pile drivability. As it is difficult to accurately determine the soil resistance to driving, there are often some differences between the result of pile drivability prediction and actual pile driving record. To solve this problem, finite element method and wave equation method were used to study the process of pile driving.Firstly, the basic theories of dynamic finite element method were briefly introduced. Finite element method was used to simulate pile driving process in sand and clay. The influence of impact force and soil parameters was analyzed. The variation of displacement field, stress field and extra pore water pressure around the pile were studied during continuous pile driving. The influence of consolidation in sand is discussed. The mechanism of reduction in clay undrained strength and influence factors during pile driving were analyzed.Secondly, the basic principles and numerical solution of wave equation method were expounded. The GRLWEAP program was briefly described, and selection methods of the main parameters were summarized.Finally, pile driving records of 36 steel pipe piles in offshore engineerings in the Bohai Sea Aeras were collected and analyzed, and variation features of soil resistance in different soil stratus were summarized. Based on actual pile driving records, soil resistances were determined in sand and clay by wave equation back analysis method, and were compared with the soil resistance calculated by existing method. Then the determination method of soil resistance to driving was improved, and the improved method was validated by project cases.