波浪荷载作用下填土对筒基式大圆筒结构稳定性的影响

摘要：筒基式大圆筒结构是一种新型港口与海岸工程结构, 依靠下部筒型基础沉入土中维持结构稳定。为了研究波浪荷载作用下填土对筒基式大圆筒结构稳定性的影响，建立了两种筒基式大圆筒结构的非线性数值分析模型。通过对比分析波浪荷载作用下填土对筒基式大圆筒结构的筒壁土压力分布、筒体能承受的水平极限荷载以及筒顶水平位移等规律，为筒基式大圆筒结构的设计和施工提供理论依据。结果表明：当有填土作用时，结构的极限承载力远高于设计波浪荷载，安全系数有大幅提升，筒基式大圆筒结构处于稳定状态。

关键词：筒基式大圆筒结构；稳定性；有限元模型；土压力

Abstract: The large cylindrical structure is a new type of structure applied in port and coastal engineering, the stability of which is sustained by the bucket foundation penetrated in soft soil. In order to study the influences of filling on the stability of large cylindrical structure under the wave load, nonlinear numerical model of two types of large cylindrical structure is constructed. Through comparative analysis of the earth pressure distribution on the cylinder wall, the level ultimate load which the cylinder can withstand and the cylinder top horizontal displacement with filling under the wave load, it provides a theoretical basis for the design and construction of large cylindrical structures. The results showed that: With the filling behind the cylinder, the ultimate bearing capacity of the structure is much higher than the design wave load, and the factor of safety has increased dramatically. The large cylindrical structure is in a stable state.

Key word: large cylindrical structure; stability; finite element model; earth pressure

引言

随着我国海运业的蓬勃发展，港口工程的建港处大多软土层较厚，在淤泥质土中开挖难度较大，因此大量的新型水工结构应运而生，大圆筒结构就是其中之

一。筒基式大圆筒结构由沉入软土地基中的无底空心圆筒组成, 上部由单排空心圆筒形成挡浪墙[1,2]。目前国内外学者在理论经验公式推导[3,4]、试验研究[ 5,6]以及有限元分析[ 7,8]等方面取得了大量的研究成果，现有的国内研究中，对影响筒基式大圆筒结构稳定性的诸多因素进行了大量分析[9-13]，但在研究过程中较少考虑由筒后填土对大圆筒结构稳定性的影响。

为了深入研究填土对筒基式大圆筒结构稳定性的影响，本文拟采用有限元软件ABAQUS建立筒后无填土和筒后有填土的三维有限元模型，分别对比分析波浪荷载作用下填土对筒基式大圆筒结构的筒壁土压力分布、筒顶水平位移、以及