基于有限元软件单元生死功能模拟局部冲刷坑的形成,并联合使用Swipe加载法和固定位移比法,研究局部冲刷后桶型基础在竖向荷载V、水平荷载H及弯矩M复合加载下的承载能力变化。结果表明：局部冲刷作用对桶型基础水平和弯矩极限承载力削弱程度明显;V-H和V-M这2种复合加载模式下,增大竖向荷载V会提高桶基水平和弯矩极限承载力;局部冲刷后V-H和V-M破坏包络线具有相似曲线形状,据此提出数学表达式;H-M复合加载下桶基在第一象限内的破坏包络线呈单调递减趋势,且随着冲刷深度增加其承载能力呈抛物线趋势下降。通过单调及二维复合加载明确了冲刷作用后桶型基础承载力变化,进一步绘制出冲刷深度Sd=0.2D工况下V-H-M三维破坏包络面,可为实际工程中冲刷作用后桶型基础受复合荷载时的承载状况提供参考。
Abstract
Based on the finite element software, the formation of local scour hole was simulated by model change function. Swipe and probe method were combined to study the bearing capacity of bucket foundation under the combined loading of vertical load V, horizontal load H and bending moment M after local scour. The results show that both the horizontal ultimate bearing capacity and bending moment ultimate bearing capacity are both weakened deeply by local scour. Under the combined loading of V-H and V-M, horizontal and bending moment ultimate bearing capacity of bucket foundation can be increased by appropriate increasing vertical load V. The failure envelope lines of V-H and V-M after local scour have similar curve shapes, furthermore, a mathematical expression is proposed to approximate the failure envelopes of V-H and V-M. The H-M failure envelope lines of bucket foundation in the first quadrant shows a monotonically decreasing trend, which is obviously affected by local scour. With increasement of scour depth, the bearing capacity of bucket foundation decreases in a parabolic trend. Through monotonic and two-dimensional combined loading, the bearing capacity change of bucket foundation after local scour is clarified. Finally, the V-H-M three-dimensional failure enveloping surface under Sd=0.2D is drawn, which plays a reference role for the bearing condition of bucket foundations in actual engineering after local scour action.
关键词
海上风电 /
基础 /
冲刷 /
复合加载 /
极限承载力 /
破坏包络面
Key words
offshore wind turbines /
foundation /
scour /
combined loading /
ultimate bearing capacity /
failure envelopes
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基金
国家自然科学基金优秀青年科学基金（51822904）; 国家自然科学基金山东联合基金（U1906234; U1706223）
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