A Study On Working Mechanism Of Bucket Foundation Under Cyclic Loads

With the increasing depletion of land resources, people will develop and utilize marine resources on a large scale, and a lot of thick weak and soft ground is inevitably encountered when we explore the marine resources process. In this conditions, people need urgently a new and economical foundation to apply to the soft ground. As a new type foundation, bucket foundation is being researched and applied in recent years. The bucket foundation covered some defects of the traditional pile foundation and gravity-type foundation, such as high engineering costs, structural complexity, inconvenient transport and the inability to recycle. Based on such advantages, the bucket foundation has been widely used around the world since then. In the past few years, the bucket foundation has been also widely used in breakwater engineering. Because of its short period of application to engineering practices, the theoretical decision on the rotation centre and horizontal bearing capacity of the bucket foundation has yet to be agreed. In this paper, the studies are emphasized on limit analysis method and finite element method of evaluating the horizontal bearing capacity and the rotation point of bucket foundation in soft ground. The main research contents are as follows:1. Based on the numerical analysis and limit analysis methods, a rotation centre formula is provided in this paper. This formula indicates the bucket slides horizontally when the embedded depth of the bucket foundation is small, and the rotation centre is located at infinity; the rotation centre is located below the mud surface at a depth of (2/3)H when the embedded depth of the foundation is close to infinity (assuming the bucket foundation does not generate shear failure). The formula suggested in this paper has considered both shallow foundations and deep foundations.The results are compared with numerical simulation and pile foundation specification. This method can satisfactorily consider the engineering conditions and the result is accurate in determining the rotation centre.2. Improving the limit analysis method, a horizontal bearing capacity formula is set up. In the derivation of formula process, we suppose the soil pressure meet the winkler hypothesis. The result shows that the horizontal bearing capacity is feasible and applicable in comparison to other theoretical results and test results.3. Through the analysis of a series of numerical models, the result shows the bucket foundation’s failure due to the bucket foundation rotation and a little horizontal sliding. Moreover, the stability of the bucket foundation with compartment is better than the no compartment, and this reason makes the horizontal bearing capacity of the former is obviously larger than the latter. With the increasing number of cyclic loading on the bucket foundation whatever it has compartment or no, the horizontal bearing capacity of the bucket foundation is gradually reduced. At the same time,...