Nonlinear Analysis of Flexible Pile near Undrained Clay Slope under Lateral Loading

In this paper, a method is developed for nonlinear analysis of laterally loaded long-flexible pile near undrained clay slope. The ideal elastic-plastic p-y curve model is used as the basic calculation model to study the pile-soil interaction system. To consider the slope effect on the soil resistance along with pile length, related reduction function expressions of soil resistance are selected by assessing the existing methods. A finite difference iteration scheme is proposed to solve the pile’s deflection curve equations to obtain nonlinear response of pile. The developed method is validated by comparing its results with the existing method, which shows a good agreement. A number of parameters analyses are carried out, and effects of different influence factors on laterally loaded pile are further discussed.

Nonlinear Stress Analysis of Flexible Pile Composite Foundation by Energy Method

To calculate the stress of cement-soil pile (flexible pile) in composite foundation accurately and overcome the defective preposition that the pile and the soil are elastic, the nonlinear analysis and calculation of pile-soil stress by adopting the energy method are performed. First, on the basis of the universally adopted load transfer method, it is assumed that the friction and the relative displacement of the pile shaft conform with the elastic-plastic relationship. Then, the modified Cam-clay model is introduced to calculate the compressive amount of soil around the pile. Further, the stress and strain characteristics curve of the flexible pile is used to calculate the compression of the pile, deducing the energy equation of the pile and soil around the pile, establishing the total potential energy expression of the flexible pile composite foundation, and the load sharing value and the corresponding stress value of the pile-soil are obtained based on the minimum potential energy principle. Finally, this method is verified by indoor laboratory model test and the reported case. The results show that the calculated solutions are in agreement with the measurements; therefore, the calculation method is reasonable.

MODEL TESTING OF PILED CLUSTERS AND LARGE MONO-PILES OF IMPROVED DESIGN

When constructing piled clusters and structures supported by large mono-piles, piles designed are used to take up significant lateral and pressing-in loads. New effective and less resource-demanding design of piled cluster was considered before. At this paper some results of its model testing in laboratory conditions are analyzed and discussed. To increase energy-absorbing capacity of mooring/fender dolphins it was worked out and researched a new design of combined tubular mono-pile structure, incorporating internal flexible pile and damping element placed at the zone of pile head. This design has been tested by laboratory experiments using small scale model. Obtained results confirm its effectiveness and practicability.