Numerical Analysis Of Bearing Properties Of Bucket Foundation Deepwater Breakwater Under Horizontal Load

In order to meet competition of the international shipping market after joining the WTO, the harbor and coastal engineering in China had been an unprecedented development. In recent years, with the increasing of depth of the ship’s draft, the breakwater and no cover dock buildings began to expand in deep water, but in China the most active coastal regions about economy, such as Yangtze Estuary, the Pearl River estuary and Tianjin Bohai Bay,were widely distributed in soft soil. Because traditional breakwaters which needed higher foundation conditions, could not meet the condition of soft soil. So building deepwater breakwater structure under the unfavorable natural conditions of big waves, urgent flow, depth and soft soil had become a serious problem for each coastal engineering research, design and construction units.Bucket foundation deepwater breakwater which applied to the coast conditions of deeper waters and soft soil was a new port and coastal engineering structure which was used in recent years. Meanwhile, the new structure had advantages of the less field work, simple construction and the less construction period,so bucket foundation deepwater breakwater was a new breakwater structure which had broad application prospect and a lot of advantages. However, due to the short time of appearance, the relevant theory of the new structure which was complex was not perfect. In particular, the state of ultimate bearing capacity of bucket foundation deepwater breakwater structure presented characteristics at the time of structural damage, field trial was seldom able to achieve this load. Due to high speed,centrifuge test could not be conducted careful study of the earth pressure on the foundation bucket and the process when bucket foundation deepwater breakwater reached the ultimate bearing capacity, and the finite element model made up for these deficiencies. This article would use the finite element software ABAQUS to research foundation bucket soil pressure and bearing capacity of bucket foundation deepwater breakwater under horizontal load, it included the following aspects:1. Through analyzing the process of bearing horizontal load until the destruction about bucket deepwater breakwater, it attained that when bucket foundation deepwater breakwater reached the ultimate bearing capacity,the soil which was in the lower and the outer of foundation bucket of back-wave side had big displacement and became larger wedge failure zone; Plastic strain area of foundation soil in back-wave side increased with horizontal load increasing,when foundation destroyed,plastic strain areas join together; So to improve strength of soil which was outer of foundation bucket of back-wave side counld effectively improve the bearing capacity of bucket foundation deepwater breakwater.This paper deemed that the failure mode of the ultimate bearing capacity was that the meeting-wave side of breakwater had upward displacement and the back-wave side of breakwater had downward displacement, and the whole breakwater had rotation around certain point below foundation bucket,when foundation soil of back-wave side appeared complete plastic zone, breakwater appeared rotation instability with large displacement or large angle.2. Through comparing calculation of changing parameters, it attained the influence of bearing capacity of bucket foundation deepwater breakwater in different soil, heavy pressure and ratios of length and radius. With the increase of the deformation modulus and shear strength of soil, the bearing capacity and the ultimate bearing capacity of the breakwater increased, but when the deformation modulus increased to a certain value, the influence on the ultimate bearing capacity of the breakwater was not significant. The heavy pressure in bucket foundation deepwater breakwater was in a certain range,it was helpful to improve the ultimate bearing capacity of bucket foundation deepwater breakwater, when heavy pressure exceeded the scope, its ultimate bearing capacity decreased; When the load was small, the influence of ratios of length and radius of foundation bucket on bearing capacity was small, when the load exceeded a certain value, the bearing capacity increased with the increase of ratios of length and radius.This paper deemed that improving ratios of length and radius of foundation bucket and shear modulus of soil, it might significantly increased the ultimate bearing capacity.The conclusions would provide theoretical basis for design and construction personnel in port engineering3. By analysing the characteristics of earth pressure on the internal and external of foundation bucket and the changes at the bottom of the foundation bucket wall and the foundation bucket under different horizonal loads. it concluded that with the increase of the horizontal load, the earth pressure on foundation bucket of meeting-wave side decreased continuously, the earth pressure on foundation bucket of back-wave side increased, the active earth pressure appeared on foundation bucket of meeting-wave side, the passive earth pressure appeared on foundation bucket of back-wave side. When reaching a certain load, it had a tendency to separate between soil and the upper of foundation bucket of meeting-wave side.The change of earth pressure in foundation bucket was not obvious, so in the actual engineering calculation on the stability it was suggested to simplify into static earth pressure for simplicity; Bucket foundation deepwater breakwater relyed mainly on earth pressure and frictional resistance of foundation bucket wall to maintain stability.