筒型基础防波堤稳定性简化计算方法

筒型基础防波堤是一种新型港口与海岸工程结构，依靠下部筒体沉入土中维持结构稳定。结合实际工程，建立了筒型基础防波堤稳定性分析的三维弹塑性有限元模型，得出了其失稳模式为绕基础筒底以下某点发生转动失稳。通过对结构进行极限状态受力分析，建立了基于实际转动点的结构稳定性计算方法，对稳定性计算模型和土体作用力计算公式等进行了检验。在此基础上，将转动点移至基础筒底部距结构中心线水平距离为h′的位置，以此作为结构倾覆破坏时的假想支撑点，建立了基于重力式结构稳定性验算模式的筒型基础防波堤稳定性分析的简化方法。通过不同基础尺度下计算结果的分析比较，建议了h′的取值。与有限元计算结果的比较表明，建立的简化计算方法具有较高的精度，可供实际工程参用。

A simplified calculation method for stability of bucket foundation breakwater

The bucket foundation breakwater is a new type of structure applied to port and coastal engineering; of which the stability is sustained by the bucket foundation penetrated in soft soil. In terms of a practical project, a 3D elasticplastic finite element model is established for stability analysis of the bucket foundation breakwater; and it is shown that the instability mode is rotation of the bucket foundation breakwater around a point below foundation base. Through analysis of forces on the structure in limit state, a stability calculation method based on the actual rotation point is set up. The stability calculation model and calculation formulas for soil forces, etc., in the model are tested by comparing with the results calculated by finite element method. On this basis, a simplified calculation method for the bucket foundation breakwater founded on the stability checking mode of gravity structure is established by moving the rotation point to the foundation base as the imaginary supporting point when the structure is overturning. And the horizontal distance between the imaginary supporting point and the central line of the structure is expressed as h′, the value of which is suggested by analyzing the results calculated in different foundation scales. In comparison to finite element method, the results indicate that the simplified method has high accuracy and could be a reference for practical projects.