| 摘要: |
| 作为新型基础，负压桶基础具有较好的技术经济性。针对负压桶施工关键控制指标土塞隆起率的控制，通过开展粉质黏土中的模型试验，研究了不同负压加载模式对施工效率及土塞隆起率的影响。试验结果表明不同负压加载模式下的负压荷载均位于DNV规范方法获得的所需负压和临界负压之间，且达到相同贯入深度负压消散模式负压大于负压保持试验。较大单级荷载下的负压消散模式对土塞隆起率控制效果最优，并保持了一定的施工效率。理论分析表明，负压桶内压力随深度变化率越大桶体内侧摩阻力越大，土塞越难以形成，并从超孔隙水压力结果解释了负压消散模式下的土塞隆起率降低机理。土压力结果表明负压消散模式下桶内土体对桶壁的有效应力高于负压保持加载模式下结果，前者的侧摩阻力也更大。 |
| 关键词: 负压桶 土塞 土应力 超孔隙水压力 |
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| Experiment and analysis on penetration of suction bucket foundation |
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FU Kun, LIU Zhan-guo, YIN Liao-yuan, LISEN
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Technology Center of CCCC Third Harbor Engineering Co., Ltd.
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| Abstract: |
| As a new type of foundation, the suction bucket foundation has good technical and economic performances compared with traditional foundations. The key construction parameter, soil plug, and construction efficiency are analyzed through model tests of a suction bucket foundation in silty clay with different suction pressure applied. Tests reveal that suction pressure in different suction pressure applying patterns are between the required value and critical value calculated by the DNV standard. In addition, the suction pressure in suction releasing pattern is larger than that in suction maintaining pattern for suction bucket to reach the same depth. The least soil plug degree is obtained in the suction releasing pattern with a large suction pressure increment provided penetration efficiency is assured. Theoretical analysis shows that the inside friction resistance increases with the gradient of inside pressure along depth and large friction resistance restricts the formation of soil plug. The mechanism of reduced soil plug in suction releasing pattern is explained by the excess pore water pressure results. The earth pressure results show that the normal effective stress mobilized on the bucket wall in the suction releasing pattern is larger than it in the suction maintaining pattern. Accordingly, the side friction mobilized of the former is also larger. |
| Key words: suction bucket foundation soil plug soil stress excess pore water pressure |
