开展砂土中筒型基础吸力沉贯的系列模型试验,测试筒型基础下沉过程中吸力的发挥过程,并通过反分析得出筒内外土体渗透系数比的变化规律。结果表明：当筒内土体出现管涌现象时,筒内负压会瞬间降低;随着沉贯深度的增加,临界吸力值也逐渐增大;此外,筒内外土体的渗透系数比呈指数函数型增长;假设在沉贯过程中土体的渗透系数不变,则临界吸力的预测结果均小于实测值。根据试验结果改进砂土中筒型基础沉贯过程临界吸力的计算公式,并进行工程案例验证。
Abstract
Critical suction is a crucial controlling factor for the penetration of bucket foundations into sand. Most of the existing methods predict the critical suction based on pure seepage numerical analysis, but they cannot reflect the changes in soil permeability coefficients inside and outside the bucket during foundation installation process, also lack of actual data to rerify the theortetical method. A series of model tests were conducted on the suction of the bucket foundation in sand, including testing the suction process during foundation penetration and obtaining the permeability coefficient ratio change law through reverse analysis. The results show that when the soil in the bucket Produces piping phenomenon, the negative pressure in the bucket is instantly reduced. As immersion depth increases, so does the critical suction value. Additionally, the ratio of permeability coefficients between soil inside and outside of the bucket increases as a power function. Assuming that soil permeability coefficient remains constant during penetration, prediction results for critical suction are obtained. According to the test results, the calculation formula of critical suction during bucket foundation penetration in sand is improved and an engineering case study is conducted.
关键词
海上风电 /
筒型基础 /
吸力沉贯 /
临界吸力 /
渗流减阻
Key words
offshore wind power /
bucket foundation /
suction penetration /
critical suction /
seepage drag reduction
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基金
国家杰出青年科学基金（51825904）; 天津市研究生科研创新项目（2021YJSB132）
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